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Publikationen VS: Bibliographie BibTeX

 
@inproceedings {INPROC-2017-58,
   author = {Mohamed Abdelaal and Frank Duerr and Kurt Rothermel and Susanne Becker and Dieter Fritsch},
   title = {{GraMap: QoS-Aware Indoor Mapping Through Crowd-Sensing Point Clouds with Grammar Support}},
   booktitle = {Proceedings of the 14th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous'17). Melbourne, VIC, Australia, November 7-10, 2017},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2017},
   isbn = {https://doi.org/10.1145/3144457.314443},
   keywords = {Indoor Mapping; 3D Point Clouds; Energy Efficiency; Formal Grammars},
   language = {Englisch},
   cr-category = {C.3 Special-Purpose and Application-Based Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-58/INPROC-2017-58.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-58&engl=0}
}
@inproceedings {INPROC-2017-55,
   author = {Thomas Kohler and Christian B{\"a}umlisberger and Frank D{\"u}rr and Kurt Rothermel},
   title = {{InFEP - Lightweight Virtualization of Distributed Control on White-box Networking Hardware}},
   booktitle = {2017 International Workshop on Management of SDN and NFV Systems (ManSDNNFV2017)},
   editor = {IFIP/IEEE},
   address = {Tokyo, Japan},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2017},
   keywords = {Software-defined Networking; Control Plane Distribution; Virtualization},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-55/INPROC-2017-55.pdf},
   contact = {thomas.kohler@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-55&engl=0}
}
@inproceedings {INPROC-2017-52,
   author = {David Richard Sch{\"a}fer and Kurt Rothermel and Muhammad Adnan Tariq},
   title = {{Exploring the Search Space between Active and Passive Workflow Replication}},
   booktitle = {Proceedings of the 10th IEEE International Conference on Service-Oriented Computing and Applications (SOCA), Kanazawa, Japan, November 22-25, 2017},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2017},
   keywords = {SOA; availability; workflows; replication},
   language = {Deutsch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-52/INPROC-2017-52.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-52&engl=0}
}
@inproceedings {INPROC-2017-51,
   author = {Thomas Bach and Muhammad Adnan Tariq and Ruben Mayer and Kurt Rothermel},
   title = {{Knowledge is at the Edge! How to Search in Distributed Machine Learning Models}},
   booktitle = {OTM 2017 Conferences},
   publisher = {Springer International Publishing},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--19},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2017},
   doi = {10.1007/978-3-319-69462-7_27},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-51/INPROC-2017-51.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-51&engl=0}
}
@inproceedings {INPROC-2017-50,
   author = {Naresh Ganesh Nayak and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Routing Algorithms for IEEE802.1Qbv Networks}},
   booktitle = {In the 15th International Workshop on Real-Time Networks, RTN-2017},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2017},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-50/INPROC-2017-50.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-50&engl=0}
}
@inproceedings {INPROC-2017-46,
   author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Understanding Vulnerabilities of Location Privacy Mechanisms against Mobility Prediction Attacks}},
   booktitle = {Proceedings of the 14th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services, Melbourne, VIC, Australia, November 7–10, 2017 (MobiQuitous’17)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2017},
   isbn = {ACM ISBN: 978-1-4503-5368-7/17/11, DOI:10.1145/3144457.314450544505},
   keywords = {location privacy; attack algorithms; semantic location information; mobility prediction; hidden Markov models},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     D.2 Software Engineering,     K.4.1 Computers and Society Public Policy Issues,     G.3 Probability and Statistics},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-46/INPROC-2017-46.pdf},
   contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-46&engl=0}
}
@inproceedings {INPROC-2017-43,
   author = {Ruben Mayer and Ahmad Slo and Muhammad Adnan Tariq and Kurt Rothermel and Manuel Gr{\"a}ber and Umakishore Ramachandran},
   title = {{SPECTRE: Supporting Consumption Policies in Window-Based Parallel Complex Event Processing}},
   booktitle = {Proceedings of Middleware ’17, Las Vegas, NV, USA, December 11–15, 2017},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--13},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2017},
   doi = {10.1145/3135974.3135983},
   language = {Deutsch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-43/INPROC-2017-43.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Distributed Complex Event Processing (DCEP) is a paradigm to infer the occurrence of complex situations in the surrounding world from basic events like sensor readings. In doing so, DCEP operators detect event patterns on their incoming event streams. To yield high operator throughput, data parallelization frameworks divide the incoming event streams of an operator into overlapping windows that are processed in parallel by a number of operator instances. In doing so, the basic assumption is that the different windows can be processed independently from each other. However, consumption policies enforce that events can only be part of one pattern instance; then, they are consumed, i.e., removed from further pattern detection. That implies that the constituent events of a pattern instance detected in one window are excluded from all other windows as well, which breaks the data parallelism between different windows. In this paper, we tackle this problem by means of speculation: Based on the likelihood of an event's consumption in a window, subsequent windows may speculatively suppress that event. We propose the SPECTRE framework for speculative processing of multiple dependent windows in parallel. Our evaluations show an up to linear scalability of SPECTRE with the number of CPU cores.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-43&engl=0}
}
@inproceedings {INPROC-2017-36,
   author = {Christian Mayer and Ruben Mayer and Majd Abdo},
   title = {{StreamLearner: Distributed Incremental Machine Learning on Event Streams: Grand Challenge}},
   booktitle = {Proceedings of the 11th ACM International Conference on Distributed and Event-based Systems},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {298--303},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2017},
   doi = {10.1145/3093742.3095103},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-36/INPROC-2017-36.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-36&engl=0}
}
@inproceedings {INPROC-2017-33,
   author = {Ruben Mayer and Muhammad Adnan Tariq and Kurt Rothermel},
   title = {{Minimizing Communication Overhead in Window-Based Parallel Complex Event Processing}},
   booktitle = {Proceedings of the 11th ACM International Conference on Distributed and Event-based Systems},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {54--65},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2017},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-33/INPROC-2017-33.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-33&engl=0}
}
@inproceedings {INPROC-2017-32,
   author = {Christoph Stach and Frank D{\"u}rr and Kai Mindermann and Saravana Murthy Palanisamy and Muhammad Adnan Tariq and Bernhard Mitschang and Stefan Wagner},
   title = {{PATRON - Datenschutz in Datenstromverarbeitungssystemen}},
   booktitle = {Informatik 2017: Digitale Kulturen, Tagungsband der 47. Jahrestagung der Gesellschaft f{\"u}r Informatik e.V. (GI), 25.09. - 29.09.2017, Technische Universit{\"a}t Chemnitz},
   publisher = {Gesellschaft f{\"u}r Informatik e.V. (GI)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {LNI},
   pages = {1--12},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2017},
   keywords = {Datenschutz; Zugriffskontrolle; Datenstr{\"o}me; Internet der Dinge; Privatheit; Sensoren},
   language = {Deutsch},
   cr-category = {K.4.1 Computers and Society Public Policy Issues,     D.4.6 Operating Systems Security and Protection},
   contact = {Senden Sie eine E-Mail an Christoph.Stach@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Softwaretechnologie, Software Engineering;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Angetrieben durch die stetig voranschreitende Digitalisierung gewinnt das Internet der Dinge (engl. IoT) immer mehr an Bedeutung. Im IoT werden technische Ger{\"a}te mit unterschiedlichen Sensoren ausgestattet und miteinander vernetzt. Dadurch werden neuartige Anwendungen beispielsweise im Bereich E-Health erm{\"o}glicht, in denen Sensordaten miteinander kombiniert und so in h{\"o}herwertige Informationen umgewandelt werden. Die von diesen Anwendungen abgeleiteten Informationen verraten viel {\"u}ber den Nutzer und m{\"u}ssen daher besonders gesch{\"u}tzt werden. H{\"a}ufig hat der Nutzer allerdings keine Kontrolle {\"u}ber die Verarbeitung seiner Daten, ganz davon zu schweigen, dass er das Ausma{\ss} und die Art der daraus ableitbaren Informationen nicht ermessen kann. In diesem Artikel stellen wir daher einen neuartigen Kontrollmechanismus vor, der private Informationen im IoT sch{\"u}tzt. Anstelle von abstrakten Datenschutzregeln f{\"u}r einzelne Sensoren definiert der Nutzer Muster, die es zu sch{\"u}tzen gilt. Ein Muster kann beispielsweise eine Kombination aus Messwerten sein, die auf eine bestimmte Krankheit schlie{\ss}en lassen. Der Nutzer definiert die zu verheimlichenden Informationen nat{\"u}rlichsprachlich, und ein Dom{\"a}nenexperte setzt diese in formale Regeln um. Sind diese Regeln zu restriktiv, so kann die Anwendung ihre angedachte Funktionalit{\"a}t nicht erbringen. Daher muss bez{\"u}glich der Servicequalit{\"a}t ein Kompromiss zwischen gew{\"u}nschter Privatheit und ben{\"o}tigter Funktionalit{\"a}t gefunden werden.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-32&engl=0}
}
@inproceedings {INPROC-2017-30,
   author = {Sukanya Bhowmik and Muhammad Adnan Tariq and Alexander Balogh and Kurt Rothermel},
   title = {{Addressing TCAM Limitations of Software-Defined Networks for Content-Based Routing}},
   booktitle = {Proceedings of Distributed and Event- Based Systems, Barcelona, Spain, June 19-23, 2017 (DEBS ’17)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2017},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-30/INPROC-2017-30.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-30&engl=0}
}
@inproceedings {INPROC-2017-22,
   author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
   title = {{ZeroSDN: A Highly Flexible and Modular Architecture for Full-range Network Control Distribution}},
   booktitle = {Proceedings of the 13th ACM/IEEE Symposium on Architectures for Networking and Communications Systems: ANCS'17, May 18-19, 2017, Beijing, China},
   editor = {ACM/IEEE},
   publisher = {Association for Computing Machinery (ACM) / Institute of Electrical and Electronics Engineers (IEEE)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--13},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2017},
   keywords = {Software-defined Networking; OpenFlow; Control Plane Distribution; Publish/Subscribe; White-box Networking},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-22/INPROC-2017-22.pdf},
   contact = {thomas.kohler@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-22&engl=0}
}
@inproceedings {INPROC-2017-09,
   author = {Ben William Carabelli and Rainer Blind and Frank D{\"u}rr and Kurt Rothermel},
   title = {{State-dependent Priority Scheduling for Networked Control Systems}},
   booktitle = {Proceedings of the 2017 American Control Conference (ACC)},
   address = {Seattle, WA, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1003--1010},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2017},
   doi = {10.23919/ACC.2017.7963084},
   keywords = {cyber-physical systems; networked control systems; optimization; scheduling},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     G.1.6 Numerical Analysis Optimization},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-09/INPROC-2017-09.pdf,     http://ieeexplore.ieee.org/document/7963084/,     https://arxiv.org/abs/1703.08311},
   contact = {ben.carabelli@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Networked control systems (NCS) have attracted considerable attention in recent years. While the stabilizability and optimal control of NCS for a given communication system has already been studied extensively, the design of the communication system for NCS has recently seen an increase in more thorough investigation. In this paper, we address an optimal scheduling problem for a set of NCS sharing a dedicated communication channel, providing performance bounds and asymptotic stability. We derive a suboptimal scheduling policy with dynamic state-based priorities calculated at the sensors, which are then used for stateless priority queuing in the network, making it both scalable and efficient to implement on routers or multi-layer switches. These properties are beneficial towards leveraging existing IP networks for control, which will be a crucial factor for the proliferation of wide-area NCS applications. By allowing for an arbitrary number of concurrent transmissions, we are able to investigate the relationship between available bandwidth, transmission rate, and delay. To demonstrate the feasibility of our approach, we provide a proof-of-concept implementation of the priority scheduler using real networking hardware.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-09&engl=0}
}
@inproceedings {INPROC-2017-07,
   author = {Ruben Mayer and Harshit Gupta and Enrique Saurez and Umakishore Ramachandran},
   title = {{The Fog Makes Sense: Enabling Social Sensing Services With Limited Internet Connectivity}},
   booktitle = {Proceedings of the 2nd International Workshop on Social Sensing},
   publisher = {Association for Computing Machinery (ACM)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {SocialSens '17},
   pages = {1--6},
   type = {Workshop-Beitrag},
   month = {April},
   year = {2017},
   doi = {http://dx.doi.org/10.1145/3055601.3055614},
   keywords = {Social Sensing; Fog Computing; Situation Awareness},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-07/INPROC-2017-07.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Social sensing services use humans as sensor carriers, sensor operators and sensors themselves in order to provide situation-awareness to applications. This promises to provide a multitude of benefits to the users, for example in the management of natural disasters or in community empowerment. However, current social sensing services depend on Internet connectivity since the services are deployed on central Cloud platforms. In many circumstances, Internet connectivity is constrained, for instance when a natural disaster causes Internet outages or when people do not have Internet access due to economical reasons. In this paper, we propose the emerging Fog Computing infrastructure to become a key-enabler of social sensing services in situations of constrained Internet connectivity. To this end, we develop a generic architecture and API of Fog-enabled social sensing services. We exemplify the usage of the proposed social sensing architecture on a number of concrete use cases from two different scenarios.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-07&engl=0}
}
@inproceedings {INPROC-2017-03,
   author = {Christoph Dibak and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Demo: Server-Assisted Interactive Mobile Simulations for Pervasive Applications}},
   booktitle = {Proceedings of the 15th IEEE International Conference on Pervasive Computing and Communications (PerCom Demos)},
   address = {Kona, Hawaii, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--3},
   type = {Demonstration},
   month = {M{\"a}rz},
   year = {2017},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     G.1 Numerical Analysis},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-03/INPROC-2017-03.pdf},
   contact = {Christoph Dibak christoph.dibak@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Emerging augmented reality devices allow for visualizing results of numerical simulations ubiquitously. This enables decision makers and engineers in the field to make better decisions. However, computation of resource-intensive simulation models on resource-poor and battery-powered mobile devices requires to drastically reduce the quality of the simulation. We therefore proposed approaches utilizing a remote server and the Reduced Basis Method (RBM) to generate a reduced model of the simulation. In our demo, we demonstrate the effectiveness of our approaches for mobile simulations. Our demo consists of two devices, a mobile device and a server. Both devices are connected via wireless network. The mobile device visualizes the result of a complex computation. Parameters of the simulation are effected by sensors of the mobile device. The user can choose between computing on the mobile device, computing solely on the server, or computing using our approach.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-03&engl=0}
}
@inproceedings {INPROC-2017-02,
   author = {Christoph Dibak and Andreas Schmidt and Frank D{\"u}rr and Bernard Haasdonk and Kurt Rothermel},
   title = {{Server-Assisted Interactive Mobile Simulations for Pervasive Applications}},
   booktitle = {Proceedings of the 15th IEEE International Conference on Pervasive Computing and Communications (PerCom)},
   address = {Kona, Hawaii, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2017},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     G.1 Numerical Analysis},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2017-02/INPROC-2017-02.pdf},
   contact = {Christoph Dibak christoph.dibak@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Currently, various hardware and software companies are developing augmented reality devices, most prominently Microsoft with its Hololens. Besides gaming, such devices can be used for serious pervasive applications, like interactive mobile simulations to support engineers in the field. Interactive simulations have high demands on resources, which the mobile device alone is unable to satisfy. Therefore, we propose a framework to support mobile simulations by distributing the computation between mobile device and a remote server. For the computation of parameter-dependent solutions of the simulation, we use the reduced basis method, which allows to drastically reduce the computation time and energy consumption. We present three approaches for the distributed execution of the reduced basis method between mobile device and server. Evaluations show that we can speed-up the numerical computation to over 131 times while using 73 times less energy compared to offloading everything to a server.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2017-02&engl=0}
}
@inproceedings {INPROC-2016-41,
   author = {Stephan Schnitzer and Simon Gansel and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Real-time scheduling for 3D GPU rendering}},
   booktitle = {11th IEEE International Symposium on Industrial Embedded Systems (SIES)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2016},
   doi = {10.1109/SIES.2016.7509411},
   keywords = {automobiles; graphical user interfaces; graphics processing units; rendering (computer graphics); 3D GPU rendering; GPU sharing; real-time GPU scheduling framework; real-time scheduling; automotive HMI; embedded systems},
   language = {Englisch},
   cr-category = {H.5.2 Information Interfaces and Presentation User Interfaces,     I.3.m Computer Graphics Miscellaneous},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-41/INPROC-2016-41.pdf,     http://dx.doi.org/10.1109/SIES.2016.7509411},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {3D graphical functions in cars enjoy growing popularity. For instance, analog instruments of the instrument cluster are replaced by digital 3D displays as shown by Mercedes-Benz in the F125 prototype car. The trend to use 3D applications expands into two directions: towards more safety-relevant applications such as the speedometer and towards third-party applications, e.g., from an app store. In order to save cost, energy, and installation space, all these applications should share a single GPU. GPU sharing brings up the problem of providing real-time guarantees for rendering content of time-sensitive applications like the speedometer. To solve this problem, we present a real-time GPU scheduling framework which provides strong guarantees for critical applications while still giving as much GPU resources to less important applications as possible, thus ensuring a high GPU utilization. Since current GPUs are not preemptible, we use the estimated execution time of each GPU rendering job to make the scheduling decisions. Our evaluations show that our scheduler guarantees given real-time constraints, while achieving a high GPU utilization of 97\%. Moreover, scheduling is performed highly efficient in real-time with less than 10 us latency.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-41&engl=0}
}
@inproceedings {INPROC-2016-34,
   author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Increasing the Efficiency of Code Offloading in n-tier Environments with Code Bubbling}},
   booktitle = {Proceedings of the 13th Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2016},
   isbn = {978-1-4503-4750-1/16/11},
   doi = {dx.doi.org/10.1145/2994374.2994375},
   keywords = {Mobile Cloud Computing; Multi-tier Code Offloading; Cyber Foraging; Code Bubbling; n-tier environment},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   contact = {Florian.Berg@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Code offloading strives for increasing the energy efficiency and execution speed of mobile applications on resource-constrained mobile devices. First approaches considered only a code offloading between two (or three) tiers, executing code either locally on the mobile device or remotely on a powerful server in the vicinity or in a distant cloud. However, new execution environments comprise multiple tiers, containing highly distributed heterogeneous resources. We present in this paper our Code Bubbling Offload System (CoBOS). CoBOS targets n-tier environments containing highly distributed heterogeneous resources with different performance characteristics and cost implications. In such n-tier environments, it is very costly for a resource-constrained mobile device to gather a global view on available resources. As a result, we propose the novel concept of code bubbling. Code bubbling moves code dynamically and adaptively towards more powerful and more distant tiers, enabling an efficient and scalable code offloading in n-tier environments. Each tier makes autonomous decisions to execute code in the tier or forward it further to the next tier. To support such a recursive escalation of code along autonomous tiers, CoBOS offloads self-contained offload requests that possess all of the required information for the processing. Our real-world evaluation shows that CoBOS decreases the energy consumption by 77\% and the execution time by 83\% for code offloading in n-tier environments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-34&engl=0}
}
@inproceedings {INPROC-2016-32,
   author = {Frank D{\"u}rr and Naresh Ganesh Nayak},
   title = {{No-wait Packet Scheduling for IEEE Time-sensitive Networks (TSN)}},
   booktitle = {24th International Conference on Real-Time Networks and Systems, RTNS-2016},
   address = {Brest, France},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2016},
   keywords = {Time-sensitive network, TSN, Real-time communication, Job shop scheduling problem, Tabu search, IEEE 802.1Qbv},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-32/INPROC-2016-32.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The IEEE Time-sensitive Networking (TSN) Task Group has recently standardized enhancements for IEEE 802.3 networks for enabling it to transport time-triggered traffic (aka scheduled traffic) providing them with stringent bounds on network delay and jitter while also transporting best-effort traffic. These enhancements primarily include dedicating one queue per port of the switch for scheduled traffic along with a programmable gating mechanism that dictates which of the queues are to be considered for transmission. While the IEEE 802.1Qbv standards define these mechanisms to handle scheduled traffic, it stops short of specifying algorithms to compute fine-grained link schedules for the streams of scheduled traffic. Further, the mechanisms in TSN require creation of so-called guard bands to isolate scheduled traffic from the best-effort traffic. These guard bands may potentially result in bandwidth wastage, and hence schedules with lower number of guard bands are preferred. In this paper, we introduce the No-wait Packet Scheduling Problem (NWPSP) for modelling the scheduling in IEEE Time-sensitive Networks and map it to the No-wait Job-shop Scheduling Problem (NW-JSP), a well-known problem from the field of operational research. In particular, we present a Tabu search algorithm for efficient computing of schedules and a schedule compression technique to reduce number of guard bands in schedule. Our evaluations show that our Tabu search algorithm can compute near-optimal schedules for over 1500 flows and the subsequent schedule compression reduces the number of guard bands on an average by 24\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-32&engl=0}
}
@inproceedings {INPROC-2016-31,
   author = {Naresh Ganesh Nayak and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Time-sensitive Software-defined Network (TSSDN) for Real-time Applications}},
   booktitle = {Proceedings of the 24th International Conference on Real-Time Networks and Systems, RTNS 2016},
   address = {Brest, France},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2016},
   language = {Deutsch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-31/INPROC-2016-31.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Cyber-physical systems (CPS), like the ones used in industrial automation systems, are highly time-sensitive applications demanding zero packet losses along with stringent real-time guarantees like bounded latency and jitter from the underlying network for communication. With the proliferation of IEEE 802.3 and IP networks, there is a desire to use these networks instead of the currently used fieldbuses for time-sensitive applications. However, these networking technologies, which originally were designed to provide best effort communication services, lack mechanisms for providing real-time guarantees. In this paper, we present Time-Sensitive Software-Defined Networks (TSSDN), which provide real-time guarantees for the time-triggered traffic in time-sensitive systems while also transporting non-time-sensitive traffic. TSSDN provides these guarantees by bounding the non-deterministic queuing delays for time-sensitive traffic. To this end, it exploits the logical centralization paradigm of software-defined networking to compute a transmission schedule for time-sensitive traffic initiated by the end systems based on a global view. In particular, we present various Integer Linear Program (ILP) formulations that solve the combined problem of routing and scheduling time-triggered traffic. Moreover, we show that end systems can comply with a given schedule with high precision using user-space packet processing frameworks. Our evaluations show that TSSDN has deterministic end-to-end delays ($<$= 14 us on our benchmark topology) with low and bounded jitter ($<$= 7 us).},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-31&engl=0}
}
@inproceedings {INPROC-2016-18,
   author = {Sukanya Bhowmik and Muhammad Adnan Tariq and Jonas Grunert and Kurt Rothermel},
   title = {{Bandwidth-Efficient Content-Based Routing on Software-Defined Networks}},
   booktitle = {Proceedings of the ACM International Conference on Distributed and Event-based Systems (DEBS 2016); Irvine, California, US, June 20-24, 2016},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2016},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-18/INPROC-2016-18.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the vision of Internet of Things gaining popularity at a global level, efficient publish/subscribe middleware for communication within and across datacenters is extremely desirable. In this respect, the very popular Software-defined Networking (SDN), which enables publish/subscribe middleware to perform line-rate filtering of events directly on hardware, can prove to be very useful. While deploying content filters directly on switches of a software-defined network allows optimized paths, high throughput rates, and low end-to-end latency, it suffers from certain inherent limitations w.r.t. no. of bits available on hardware switches to represent these filters. Such a limitation affects expressiveness of filters, resulting in unnecessary traffic in the network. In this paper, we explore various techniques to represent content filters expressively while being limited by hardware. We implement and evaluate techniques that i) use workload, in terms of events and subscriptions, to represent content, and ii) efficiently select attributes to reduce redundancy in content. Moreover, these techniques complement each other and can be combined together to further enhance performance. Our detailed performance evaluations show the potential of these techniques in reducing unnecessary traffic when subjected to different workloads.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-18&engl=0}
}
@inproceedings {INPROC-2016-17,
   author = {Ruben Mayer and Christian Mayer and Muhammad Adnan Tariq and Kurt Rothermel},
   title = {{GraphCEP - Real-time Data Analytics Using Parallel Complex Event and Graph Processing}},
   booktitle = {Proceedings of the 10th ACM International Conference on Distributed Event-Based Systems, DEBS'16},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2016},
   doi = {10.1145/2933267.2933509},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-17/INPROC-2016-17.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In recent years, the proliferation of highly dynamic graph-structured data streams fueled the demand for real-time data analytics. For instance, detecting recent trends in social networks enables new applications in areas such as disaster detection, business analytics or health-care. Parallel Complex Event Processing has evolved as the paradigm of choice to analyze data streams in a timely manner, where the incoming data streams are split and processed independently by parallel operator instances. However, the degree of parallelism is limited by the feasibility of splitting the data streams into independent parts such that correctness of event processing is still ensured. In this paper, we overcome this limitation for graph-structured data by further parallelizing individual operator instances using modern graph processing systems. These systems partition the graph data and execute graph algorithms in a highly parallel fashion, for instance using cloud resources. To this end, we propose a novel graph-based Complex Event Processing system GraphCEP and evaluate its performance in the setting of two case studies from the DEBS Grand Challenge 2016.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-17&engl=0}
}
@inproceedings {INPROC-2016-16,
   author = {Sukanya Bhowmik and Muhammad Adnan Tariq and Lobna Hegazy and Kurt Rothermel},
   title = {{Hybrid Content-based Routing Using Network and Application Layer Filtering}},
   booktitle = {Proceedings of the 36th IEEE International Conference on Distributed Computing Systems (ICDCS 2016), Nara, Japan, June 27-30, 2016},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2016},
   keywords = {Content-based Routing; Publish/Subscribe; Software-defined Networking; Network Virtualization; Hybrid Routing},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-16/INPROC-2016-16.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Over the past few decades, content-based publish/subscribe has been primarily implemented as an overlay network of software brokers. Even though such systems provide the possibility of bandwidth efficient expressive filtering in software, they cannot match up to the performance (in terms of end-to-end latency and throughput) of communication protocols implemented on the network layer. To exploit network layer performance benefits, recently, content-based publish/subscribe was realized using the capabilities of Software-defined Networking (SDN). While SDN allows line-rate forwarding of events by content filters directly installed on switches, it suffers from inherent hardware limitations (w.r.t. flow table size, limited availability of bits in header fields) that adversely impact expressiveness of these filters, resulting in unnecessary network traffic. In this paper, we strike a balance between purely application-layer-based and purely network-layer-based publish/subscribe implementations by realizing the first hybrid content-based middleware that enables filtering of events in both layers. Moreover, we provide different selection algorithms with varying degrees of complexity to determine the events to be filtered at each layer such that unnecessary network traffic can be minimized while also considering delay requirements of the middleware. Our hybrid middleware offers full flexibility to configure it according to the performance requirements of the system. We provide a detailed performance evaluation of the proposed selection algorithms to determine their impact on the performance of the designed hybrid middleware which we further compare to state-of-the art solutions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-16&engl=0}
}
@inproceedings {INPROC-2016-15,
   author = {David Richard Sch{\"a}fer and Andreas Wei{\ss} and Muhammad Adnan Tariq and Vasilios Andrikopoulos and Santiago G{\'o}mez S{\'a}ez and Lukas Krawczyk and Kurt Rothermel},
   title = {{HAWKS: A System for Highly Available Executions of Workflows}},
   booktitle = {Proceedings of the 13th IEEE International Conference on Services Computing: SCC'16; San Francisco, California, USA, June 27-July 2, 2016},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {130--137},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2016},
   doi = {10.1109/SCC.2016.24},
   keywords = {SOA; workflows; availability; replication; performance},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-15/INPROC-2016-15.pdf,     http://dx.doi.org/10.1109/SCC.2016.24},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The workflow technology is the de facto standard for managing business processes. Today, workflows are even used for automating interactions and collaborations between business partners, e.g., for enabling just-in-time production. Every workflow that is part of such a collaboration needs to be highly available. Otherwise, the business operations, e.g., the production, might be hindered or even stopped. Since today's business partners are scattered across the globe, the workflows are executed in a highly distributed and heterogeneous environment. Those environments are, however, failure-prone and, thus, providing availability is not trivial. In this work, we improve availability by replicating workflow executions, while ensuring that the outcome is the same as in a non-replicated execution. For making workflow replication easily usable with current workflow technology, we derive the requirements for modeling a workflow replication system. Then, we propose the HAWKS system, which adheres to the previously specified requirements and is compatible with current technology. We implement a proof-of-concept in the open-source workflow execution engine Apache ODE for demonstrating this compatibility. Finally, we extensively evaluate the impact of using HAWKS in terms of performance and availability in the presence of failures.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-15&engl=0}
}
@inproceedings {INPROC-2016-13,
   author = {Christian Mayer and Muhammad Adnan Tariq and Chen Li and Kurt Rothermel},
   title = {{GrapH: Heterogeneity-Aware Graph Computation with Adaptive Partitioning}},
   booktitle = {Proceedings of the 2016 IEEE 36th International Conference on Distributed Computing Systems (ICDCS)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {118--128},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2016},
   doi = {10.1109/ICDCS.2016.92},
   issn = {1063-6927},
   keywords = {cloud computing; data analysis; GrapH; GraphX; PowerGraph; Pregel; adaptive edge migration strategy; adaptive partitioning; data access locality; data analytics; diverse vertex traffic; expensive network links; graph vertices; graph-structured data; heterogeneity-aware graph computation; heterogeneous network; specialized graph partitioning algorithms; suboptimal partitioning decisions; vertex-centric graph processing; vertex-cut graph partitioning; Automata; Computational modeling; Data analysis; Distributed databases; Heuristic algorithms; Mirrors; Partitioning algorithms},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-13/INPROC-2016-13.pdf,     http://dx.doi.org/10.1109/ICDCS.2016.92},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Vertex-centric graph processing systems such as Pregel, PowerGraph, or GraphX recently gained popularity due to their superior performance of data analytics on graph-structured data. These systems exploit the graph structure to improve data access locality during computation, making use of specialized graph partitioning algorithms. Recent partitioning techniques assume a uniform and constant amount of data exchanged between graph vertices (i.e., uniform vertex traffic) and homogeneous underlying network costs. However, in real-world scenarios vertex traffic and network costs are heterogeneous. This leads to suboptimal partitioning decisions and inefficient graph processing. To this end, we designed GrapH, the first graph processing system using vertex-cut graph partitioning that considers both, diverse vertex traffic and heterogeneous network, to minimize overall communication costs. The main idea is to avoid frequent communication over expensive network links using an adaptive edge migration strategy. Our evaluations show an improvement of 60\% in communication costs compared to state-of-the-art partitioning approaches.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-13&engl=0}
}
@inproceedings {INPROC-2016-11,
   author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
   title = {{On the Privacy of Frequently Visited User Locations}},
   booktitle = {Proceedings of the Seventeenth International Conference on Mobile Data Management: MDM'16; Porto, Portugal, June 13-16, 2016},
   address = {Porto, Portugal},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2016},
   keywords = {Location Privacy, Location-based Applications, Semantic Locations, Visit-Frequency, Frequent locations, Geo-social networking, Location Servers, Non-trusted systems},
   language = {Englisch},
   cr-category = {K.4.1 Computers and Society Public Policy Issues,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2016-11/INPROC-2016-11.pdf},
   contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the fast adoption of location-enabled devices, Location-based Applications (LBAs) have become widely popular. While LBAs enable highly useful concepts such as geo-social networking, their use also raises serious privacy concerns as it involves sharing of location data with non-trusted third parties. In this respect, we propose an approach that protects the frequently visited locations of users, e.g., a bar, against inferences from longterm monitoring of their location data. Such inferences equate a privacy leak as they reveal a user{\^a}€™s personal behavior and interests to possibly malicious non-trusted parties. To this end, we first present a study of a dataset of location check-ins to show the existence of this threat among users of LBAs. We then propose our approach to protect visit-frequency of the users to different locations by distributing their location data among multiple third-party Location Servers. This distribution not only serves to avoid a single point of failure for privacy in our system, it also allows the users to control which LBA accesses what information about them. We also describe a number of possible attacks against our privacy approach and evaluate them on real-data from the check-ins dataset. Our results show that our approach can effectively hide the frequent locations while supporting good quality-of-service for the LBAs.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-11&engl=0}
}
@inproceedings {INPROC-2015-59,
   author = {Simon Gansel and Stephan Schnitzer and Ahmad Gilbeau-Hammoud and Viktor Friesen and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer and Ulrich Kr{\"a}mer},
   title = {{Context-aware Access Control in Novel Automotive HMI Systems}},
   booktitle = {Proceedings of 11th International Conference on Information Systems Security, ICISS 2015, Kolkata, India},
   editor = {Sushil Jajodia and Chandan Mazumdar},
   publisher = {Springer International Publishing},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {118--138},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2015},
   isbn = {10.1007/978-3-319-26961-0_8},
   language = {Englisch},
   cr-category = {D.4.6 Operating Systems Security and Protection},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-59/INPROC-2015-59.pdf,     http://link.springer.com/chapter/10.1007%2F978-3-319-26961-0_8},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The growing relevance of vehicular applications like media player, navigation system, or speedometer using graphical presentation has lead to an increasing number of displays in modern cars. This effectuates the desire for flexible sharing of all the available displays between several applications. However, automotive requirements include many regulations to avoid driver distraction to ensure safety. To allow for safe sharing of the available screen surface between the many safety-critical and non-safety-critical applications, adequate access control systems are required. We use the notion of $\backslash$emph{contexts} to dynamically determine, which application is allowed to access which display area. A context can be derived from vehicle sensors (e.g., the current speed), or be an application-specific state (e.g., which menu item is selected). We propose an access control model that is inherently aware of the context of the car and the applications. It provides delegation of access rights to display areas by applications. We implemented a proof-of-concept implementation that demonstrates the feasibility of our concept and evaluated the latency introduced by access control. Our results show that the delay reacting on dynamic context changes is small enough for automotive scenarios.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-59&engl=0}
}
@inproceedings {INPROC-2015-54,
   author = {Simon Gansel and Stephan Schnitzer and Riccardo Cecolin and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer},
   title = {{Efficient Compositing Strategies for Automotive HMI Systems}},
   booktitle = {10th IEEE International Symposium on Industrial Embedded Systems (SIES), Siegen, Germany, 2015},
   address = {Siegen},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2015},
   doi = {10.1109/SIES.2015.7185036},
   keywords = {CPU execution time; automotive HMI systems; automotive embedded platforms; cache-hybrid compositing; graphical functions; off-screen buffers; power consumption; vehicular applications},
   language = {Englisch},
   cr-category = {D.4.9 Systems Programs and Utilities,     H.5.2 Information Interfaces and Presentation User Interfaces,     I.3.6 Computer Graphics Methodology and Techniques},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-54/INPROC-2015-54.pdf,     http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7185036&isnumber=7185026},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The relevance of graphical functions in vehicular applications has increased significantly during the last years. Modern cars are equipped with multiple displays used by different applications such as speedometer, navigation system, or media players. The rendered output of the applications is stored in so-called off-screen buffers and then bitblitted to the screen buffer at the respective window sizes and positions. To guarantee the visibility of the potentially overlapping windows, the compositing has to match the z-order of the windows. To this end, two common compositing strategies Tile compositing and Full compositing are used, each having performance issues depending on how windows overlap. Since automotive embedded platforms are restricted in power consumption, installation space, and hardware cost, their performance is limited which effectuates the need for highly efficient bitblitting. In order to increase the performance in compositing the windows, we propose Hybrid Compositing which predicts the required bitblitting time and chooses the most efficient strategy for each pair of overlapping windows. Using various scenarios we show that our approach is faster than the other strategies. In addition, we propose CacheHybrid Compositing which reduces the CPU execution time of our approach by up to 66 \%. In case of an automotive scenario we show that our optimized approach saves up to 51 \% bitblitting time compared to existing approaches.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-54&engl=0}
}
@inproceedings {INPROC-2015-49,
   author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Update Consistency in Software-defined Networking based Multicast Networks}},
   booktitle = {Proceedings of the 2015 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN), San Francisco, USA, November 18-21, 2015},
   address = {San Francisco, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {177--183},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2015},
   doi = {10.1109/NFV-SDN.2015.7387424},
   keywords = {Software-defined Networking; Multicast communication; Computer network management; Concurrency Control},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.3 Network Operations,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-49/INPROC-2015-49.pdf,     http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7387424},
   contact = {thomas.kohler@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {When applying updates on distributed network elements with SDN, intra-update states may violate desired network properties, such as drop- and loop-freeness. Current stateless approaches cannot guarantee the constancy of arbitrary network invariants (correctness) in general, yet update procedures guaranteeing certain invariants do exist. In this paper, we investigate on update consistency for the case of multicast routing and show that there is no correct update procedure w.r.t. both drop- and duplicate-freeness. We show that certain updates of multicast routes inherently raise a concurrency issue, which necessarily results in the occurrence of either drops or duplicates. Furthermore, we present a generic update procedure for multicast routing updates that identifies concurrency-relevant update steps. This procedure allows for the selection of an update strategy, such that either drops or duplicates are avoided. These effects can severely degrade network performance or quality of experience. To investigate the implications of drops and duplicates, we evaluate their frequencies and impact for wide-area network scenarios both, analytically and empirically, through direct measurement in the data plane under update.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-49&engl=0}
}
@inproceedings {INPROC-2015-48,
   author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Increasing the Efficiency of Code Offloading through Remote-side Caching}},
   booktitle = {Proceedings of the IEEE 11th International Conference on Wireless and Mobile Computing, Networking and Communications: WiMob'15; Abu-Dhabi, United Arab Emirates (UAE), October 19-21, 2015},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {573--580},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2015},
   doi = {10.1109/WiMOB.2015.7348013},
   keywords = {Mobile Cloud Computing; Code Offloading; Distributed Execution; Data Replication; Function Caching},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {http://dx.doi.org/10.1109/WiMOB.2015.7348013},
   contact = {Florian.Berg@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {End users execute today on their smart phones different kinds of mobile applications like calendar apps or high-end mobile games, differing in local resource usage. Utilizing local resources of a smart phone heavily, like playing high-end mobile games, drains its limited energy resource in few hours. To prevent the limited energy resource from a quick exhaustion, smart phones benefit from executing resource-intensive application parts on a remote server in the cloud (code offloading). During the remote execution on the remote server, a smart phone waits in idle mode until it receives a result. However, code offloading introduces computation and communication overhead, which decreases the energy efficiency and induces monetary cost. For instance, sending or receiving execution state information to or from a remote server consumes energy. Moreover, executing code on a remote server instance in a commercial cloud causes monetary cost. To keep consumed energy and monetary cost low, we present in this paper the concept of remote-side caching for code offloading, which increases the efficiency of code offloading. The remote-side cache serves as a collective storage of results for already executed application parts on remote servers, avoiding the repeated execution of previously run application parts. The smart phone queries the remote-side cache for corresponding results of resource-intensive application parts. In case of a cache hit, the smart phone gets immediately a result and continues the application execution. Otherwise, it migrates the application part and waits for a result of the remote execution. We show in our evaluation that the use of a remote-side cache decreases energy consumption and monetary cost for mobile applications by up to 97\% and 99\%, respectively.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-48&engl=0}
}
@inproceedings {INPROC-2015-42,
   author = {Thomas Bach and Muhammad Adnan Tariq and Christian Mayer and Kurt Rothermel},
   title = {{Utilizing the Hive Mind - How to Manage Knowledge in Fully Distributed Environments}},
   booktitle = {OTM 2015 Conferences},
   address = {Rhodos},
   publisher = {Springer Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--18},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2015},
   keywords = {Knowledge retrieval; Distributed knowledge; Confidence-based indexing; Indexing; Query routing; Knowledge},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-42/INPROC-2015-42.pdf},
   contact = {thomas.bach@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {By 2020, the Internet of Things will consist of 26 Billion connected devices. All these devices will be collecting an innumerable amount of raw observations, for example, GPS positions or communication patterns. In order to benefit from this enormous amount of information, machine learning algorithms are used to derive knowledge from the gathered observations. This benefit can be increased further, if the devices are enabled to collaborate by sharing gathered knowledge. In a massively distributed environment, this is not an easy task, as the knowledge on each device can be very heterogeneous and based on a different amount of observations in diverse contexts. In this paper, we propose two strategies to route a query for specific knowledge to a device that can answer it with high confidence. To that end, we developed a confidence metric that takes the number and variance of the observations of a device into account. Our routing strategies are based on local routing tables that can either be learned from previous queries over time or actively maintained by interchanging knowledge models. We evaluated both routing strategies on real world and synthetic data. Our evaluations show that the knowledge retrieved by the presented approaches is up to 96.7 \% as accurate as the global optimum.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-42&engl=0}
}
@inproceedings {INPROC-2015-41,
   author = {Naresh Ganesh Nayak and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Software-defined Environment for Reconfigurable Manufacturing Systems}},
   booktitle = {Proceedings of the 5th International Conference on Internet of Things (IoT 2015)},
   address = {Seoul, South Korea},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2015},
   keywords = {Time-sensitive networks; Industry 4.0; Quality of service; Genetic Algorithm; Software-defined networks},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-41/INPROC-2015-41.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Conventional manufacturing systems like assembly lines cannot handle the constantly changing requirements of a modern-day manufacturer, which are driven by volatile market demands. In a bid to satisfy such requirements, modern manufacturing systems, comprising innumerable cyber-physical systems (CPS), aim to be reconfigurable. CPS implement production processes through an ICT infrastructure networked with sensors and actuators embedded in the shop floor. Reconfigurability, in context of manufacturing systems, must include the entire system of networked components and hence requires a flexible ICT infrastructure. Providing flexible ICT infrastructures, often, comes at the cost of diluted quality of service (QoS) guarantees. This, however, is not an option for manufacturing systems, most of which require strict QoS guarantees to function correctly. To overcome this obstacle, we propose a new software-defined environment (SDE) for reconfigurable manufacturing systems with real-time properties in this paper. Software-defined environment is an emerging technology that provides flexible ICT infrastructures modifiable using software. Our contributions include an SDE-based system architecture for dynamically configuring the underlying infrastructure for a manufacturing system. In particular, we focus on configuring the network for the time-sensitive communication flows essential for realising CPS. Moreover, we propose a pair of routing algorithms to calculate routes for these flows while configuring the network.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-41&engl=0}
}
@inproceedings {INPROC-2015-36,
   author = {Christoph Dibak and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Numerical Analysis of Complex Physical Systems on Networked Mobile Devices}},
   booktitle = {Proceedings of the 12th IEEE International Conference on Mobile Ad hoc and Sensor Systems (MASS 2015); Dallas, USA, October 19-22 2015},
   address = {Dallas},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--9},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2015},
   keywords = {mobile cloud computing; numerical applications; mobile cyber-physical systems; augmented reality},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems,     G.1.0 Numerical Analysis General},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-36/INPROC-2015-36.pdf},
   contact = {Christoph Dibak christoph.dibak@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Recently, a new class of mobile applications has appeared that takes into account the behavior of physical phenomenon. Prominent examples of such applications include augmented reality applications visualizing physical processes on a mobile device or mobile cyber-physical systems like autonomous vehicles or robots. Typically, these applications need to solve partial differential equations (PDE) to simulate the behavior of a physical system. There are two basic strategies to numerically solve these PDEs: (1) offload all computations to a remote server; (2) solve the PDE on the resource-constrained mobile device. However, both strategies have severe drawbacks. Offloading will fail if the mobile device is disconnected, and resource constraints require to reduce the quality of the solution. Therefore, we propose a new approach for mobile simulations using a hybrid strategy that is robust to communication failures and can still benefit from powerful server resources. The basic idea of this approach is to dynamically decide on the placement of the PDE solver based on a prediction of the wireless link availability using Markov Chains. Our tests based on measurement in real cellular networks and real mobile devices show that this approach is able to keep deadline constraints in more than 61 \% of the cases compared to a pure offloading approach, while saving up to 74 \% of energy compared to a simplified approach.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-36&engl=0}
}
@inproceedings {INPROC-2015-22,
   author = {Sukanya Bhowmik and Muhammad Adnan Tariq and Boris Koldehofe and Andre Kutzleb and Kurt Rothermel},
   title = {{Distributed Control Plane for Software-defined Networks: A Case Study Using Event-based Middleware}},
   booktitle = {Proceedings of the 9th International Conference on Distributed Event-based Systems, Oslo, Norway, June 29 - July 3, 2015},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2015},
   isbn = {http://doi.acm.org/10.1145/2675743.2771835},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-22/INPROC-2015-22.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Realizing a communication middleware in a software-defined network can leverage significant performance gains in terms of latency, throughput and bandwidth efficiency. For example, filtering operations in an event-based middleware can be performed highly efficiently in the TCAM memory of switches enabling line-rate forwarding of events. A key challenge in a software-defined network, however, is to ensure high responsiveness of the control plane to dynamically changing communication interactions. In this paper, we propose a methodology for both vertical and horizontal scaling of the distributed control plane that is capable of improving the responsiveness by enabling concurrent network updates in the presence of high dynamics while ensuring consistent changes to the data plane of a communication middleware. In contrast to existing scaling approaches that aim for a general-purpose distributed control plane, our approach uses knowledge of the application semantics that is already available in the design of the data plane of a communication middleware, e.g. subscriptions and advertisements in an event-based middleware. By proposing a methodology for an application-aware control distribution, we show, in the context of PLEROMA, an event-based middleware, that application-awareness is significantly beneficial in avoiding the synchronization bottlenecks for ensuring consistency in the presence of concurrent network updates and thus greatly improves the responsiveness of the control plane.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-22&engl=0}
}
@inproceedings {INPROC-2015-06,
   author = {Zohaib Riaz and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Optimized Location Update Protocols for Secure and Efficient Position Sharing}},
   booktitle = {Proceedings of the 2nd International Conference on Networked Systems: NetSys 2015; Cottbus, Germany, March 9-13, 2015},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2015},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     K.4.1 Computers and Society Public Policy Issues},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-06/INPROC-2015-06.pdf},
   contact = {zohaib.riaz@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Abstract{\^a}€”Although location-based applications have seen fast growth in the last decade due to pervasive adoption of GPS enabled mobile devices, their use raises privacy concerns. To mitigate these concerns, a number of approaches have been proposed in literature, many of which rely on a trusted party to regulate user privacy. However, trusted parties are known to be prone to data breaches [1]. Consequently, a novel solution, called Position Sharing, was proposed in [2] to secure location privacy in fully non-trusted systems. In Position Sharing, obfuscated position shares of the actual user location are distributed among several location servers, each from a different provider, such that there is no single point of failure if the servers get breached. While Position Sharing can exhibit useful properties such as graceful degradation of privacy, it incurs significant communication overhead as position shares are sent to several location servers instead of one. To this end, we propose a set of location update protocols to minimize the communication overhead of Position Sharing while maintaining the privacy guarantees that it originally provided. As we consider the scenario of frequent location updates, i.e., movement trajectories, our protocols additionally add protection against an attack based on spatio-temporal correlation in published locations. By evaluating on a set of real-world GPS traces, we show that our protocols can reduce the communication overhead by 75\% while significantly improving the security guarantees of the original Position Sharing algorithm.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-06&engl=0}
}
@inproceedings {INPROC-2015-05,
   author = {Thomas Bach and Muhammad Adnan Tariq and Boris Koldehofe and Kurt Rothermel},
   title = {{A Cost Efficient Scheduling Strategy to Guarantee Probabilistic Workflow Deadlines}},
   booktitle = {Proceedings of the International Conference on Networked Systems},
   address = {Cottbus, Germany},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2015},
   keywords = {robust workflow execution; parallel service execution; service execution},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2015-05/INPROC-2015-05.pdf},
   contact = {thomas.bach@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Today, workflows are widely used to model business processes. A recent trend is to use them to model applications in heterogeneous, large-scale distributed systems. In such systems, many, possibly mobile, providers offer independent and interchangeable services that can be used to satisfy the different activities of a workflow. Due to varying server loads, failures, and changing network characteristics, the response time of these services is highly volatile. Thus, it is hard to ensure the timely and reliable execution of workflows depending on such services. A common approach is to invoke several services in parallel to increase the probability of success. This, however, can easily lead to overprovisioning and high cost when needlessly invoked services have to be compensated. In this paper, we investigate the search space between parallel and sequential invocation of services. We propose to invoke independent services staggered over time to ensure timely workflow execution at minimal cost. Evaluations show that our approach reduces the execution cost by up to 85 \% while it guarantees to fulfill activity deadlines with 99.9 \% probability.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-05&engl=0}
}
@inproceedings {INPROC-2014-95,
   author = {Simon Gansel and Stephan Schnitzer and Ahmad Gilbeau-Hammoud and Viktor Friesen and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer},
   title = {{An access control concept for novel automotive HMI systems}},
   booktitle = {Proceedings of the 19th ACM symposium on Access control models and technologies, 2014, London, Ontario, Canada.},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {17--28},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2014},
   isbn = {978-1-4503-2939-2},
   doi = {10.1145/2613087.2613104},
   keywords = {Access Control; State-based Model; Automotive; Windows},
   language = {Englisch},
   cr-category = {D.4.6 Operating Systems Security and Protection,     H.5.2 Information Interfaces and Presentation User Interfaces},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-95/INPROC-2014-95.pdf,     http://dl.acm.org/citation.cfm?id=2613104},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The relevance of graphical functions in vehicular applications has increased significantly during the few last years. Modern cars are equipped with multiple displays used by different applications such as speedometer or navigation system. However, so far applications are restricted to using dedicated displays. In order to increase flexibility, the requirement of sharing displays between applications has emerged. Sharing displays leads to safety and security concerns since safety-critical applications as the dashboard warning lights share the same displays with uncritical or untrusted applications like the navigation system or third-party applications. To guarantee the safe and secure sharing of displays, we present a formal model for defining and controlling the access to display areas in this paper. We prove the validity of this model, and present a proof-of-concept implementation to demonstrate the feasibility of our concept.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-95&engl=0}
}
@inproceedings {INPROC-2014-94,
   author = {Stephan Schnitzer and Simon Gansel and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Concepts for execution time prediction of 3D GPU rendering}},
   booktitle = {9th IEEE International Symposium on Industrial Embedded Systems (SIES), 2014, pp.160-169, 18-20 June 2014},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {160--169},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2014},
   isbn = {10.1109/SIES.2014.6871200},
   keywords = {3D-rendering; GPU-scheduling; embedded systems; execution time prediction; real-time},
   language = {Englisch},
   cr-category = {H.5.2 Information Interfaces and Presentation User Interfaces,     I.3.m Computer Graphics Miscellaneous},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-94/INPROC-2014-94.pdf,     http://dx.doi.org/10.1109/SIES.2014.6871200},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The relevance of graphical functions in vehicular applications has increased significantly during the last years. Modern cars are equipped with multiple displays used by different applications such as speedometer, navigation system, or media players. The recent trend towards hardware consolidation to reduce hardware cost, installation space, and energy consumption, causes graphical 3D applications of different safety-criticality to share a single GPU. This requires effective real-time GPU scheduling concepts to ensure safety and isolation for 3D rendering. Since current GPUs are not preemptible, a deadline-based scheduler must know the GPU execution time of GPU commands in advance. In this work, we present a novel framework to measure and predict the execution time of GPU commands using OpenGL ES 2.0. We present prediction models for the main GPU commands relevant for 3D rendering, namely, FLUSH, CLEAR, and DRAW. For the DRAW command we propose to use the 3D bounding box of the rendered model and apply the vertex shader projection to heuristically estimate the number of fragments rendered. We finally present the implementation and evaluation of our framework, which demonstrates its feasibility and shows that good prediction accuracy can be achieved. In our evaluation using realistic scenarios the absolute prediction error of the DRAW command did not exceed 260 µs.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-94&engl=0}
}
@inproceedings {INPROC-2014-78,
   author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Optimal Predictive Code Offloading}},
   booktitle = {Proceedings of the 11th International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2014},
   doi = {10.4108/icst.mobiquitous.2014.258023},
   keywords = {Code Offloading; Markov chain; Link quality},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {http://dl.acm.org/citation.cfm?id=2692985},
   contact = {Florian.Berg@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Modern mobile devices like smart phones and tablets are equipped with powerful processing and memory resources, enabling resource-intensive mobile applications such as high-end mobile games. The main limitation, however, remains the energy resource. To improve the energy efficiency, code offloading has been proposed, which offloads code to remote servers and transfers the results back to the mobile device. Although several approaches have shown that code offloading improves energy efficiency significantly in general, they largely neglect the adverse effects of network disconnections. Therefore, we have proposed the concept of preemptive code offloading to improve energy efficiency also under link failures. It transmits so-called safe-points between server and mobile device during remote execution, enabling the re-use of partial remote results after link failures. In this paper, we improve our basic preemptive code offloading approach by optimizing the time when to generate and transmit safe-points to minimize the communication overhead and maximize energy efficiency. To find the optimal safe-point schedule, we use a predictive approach that predicts the mobile link quality in order to send safe-points before network disconnections. Moreover, we consider additional deadline constraints for code execution to ensure a minimal responsiveness of offloaded applications despite link failures. Our evaluation results show that energy efficiency can be improved significantly using our predictive offloading approach.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-78&engl=0}
}
@inproceedings {INPROC-2014-74,
   author = {Ruben Mayer and Boris Koldehofe and Kurt Rothermel},
   title = {{Meeting Predictable Buffer Limits in the Parallel Execution of Event Processing Operators}},
   booktitle = {Proceedings of the 2014 IEEE International Conference on Big Data, BigData '14},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {402--411},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2014},
   keywords = {Complex Event Processing, Stream Processing, Data Parallelization, Self-Adaptation, Quality of Service},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-74/INPROC-2014-74.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Complex Event Processing (CEP) systems enable applications to react to live-situations by detecting event patterns (complex events) in data streams. With the increasing number of data sources and the increasing volume at which data is produced, parallelization of event detection is becoming of tremendous importance to limit the time events need to be buffered before they actually can be processed by an event detector—named event processing operator. In this paper, we propose a pattern-sensitive partitioning model for data streams that is capable of achieving a high degree of parallelism for event patterns which formerly could only be consistently detected in a sequential manner or at a low parallelization degree. Moreover, we propose methods to dynamically adapt the parallelization degree to limit the buffering imposed on event detection in the presence of dynamic changes to the workload. Extensive evaluations of the system behavior show that the proposed partitioning model allows for a high degree of parallelism and that the proposed adaptation methods are able to meet the buffering level for event detection under high and dynamic workloads.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-74&engl=0}
}
@inproceedings {INPROC-2014-67,
   author = {Muhammad Adnan Tariq and Boris Koldehofe and Sukanya Bhowmik and Kurt Rothermel},
   title = {{PLEROMA: A SDN-based High Performance Publish/Subscribe Middleware}},
   booktitle = {To appear in Proceedings of the ACM/IFIP/USENIX Middleware Conference},
   publisher = {ACM press.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2014},
   doi = {10.1145/2663165.2663338},
   keywords = {Content-based Routing, Publish/Subscribe, Software-defined Networking, Network Virtualization},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-67/INPROC-2014-67.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the increasing popularity of Software-defined networks (SDN), TCAM memory of switches can be directly accessed by a publish/subscribe middleware to perform filtering operations at low latency. This way two important requirements for a publish/subscribe middleware can be fulfilled: namely bandwidth efficiency and line-rate performance in forwarding messages between producers and consumers. Nevertheless, it is challenging to sustain line-rate performance in the presence of dynamic changes in the interest of producers and consumers. In this paper, we propose and evaluate the PLEROMA middleware to realize publish/subscribe at line-rate and bandwidth efficiently in SDN. PLEROMA offers methods to efficiently reconfigure a deployed topology in the presence of dynamic subscriptions and advertisements. Furthermore, PLEROMA ensures interoperability and independent reconfiguration of multiple controlled SDN networks.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-67&engl=0}
}
@inproceedings {INPROC-2014-57,
   author = {David Richard Sch{\"a}fer and Santiago G{\'o}mez S{\'a}ez and Thomas Bach and Vasilios Andrikopoulos and Muhammad Adnan Tariq},
   title = {{Towards Ensuring High Availability in Collective Adaptive Systems}},
   booktitle = {Proceedings of the First International Workshop of Business Processes in Collective Adaptive Systems: BPCAS'14; Eindhoven, Netherlands, September 8, 2014},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2014},
   keywords = {workflows; high availability; service discovery; process fragment injection},
   language = {Englisch},
   cr-category = {D.2.0 Software Engineering General,     D.2.11 Software Engineering Software Architectures,     D.2.12 Software Engineering Interoperability,     C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-57/INPROC-2014-57.pdf},
   contact = {david.schaefer@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Collective Adaptive Systems support the interaction and adaptation of virtual and physical entities towards achieving common objectives. For these systems, several challenges at the modeling, provisioning, and execution phases arise. In this position paper, we define the necessary underpinning concepts and identify requirements towards ensuring high availability in such systems. More specifically, based on a scenario from the EU Project ALLOW Ensembles, we identify the necessary requirements and derive an architectural approach that aims at ensuring high availability by combining active workflow replication, service selection, and dynamic compensation techniques.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-57&engl=0}
}
@inproceedings {INPROC-2014-55,
   author = {Thomas Kohler and Jan-Philipp Stegh{\"o}fer and D{\'\i}dac Busquets and Jeremy Pitt},
   title = {{The Value of Fairness: Trade-offs in Repeated Dynamic Resource Allocation}},
   booktitle = {Proceedings of the 2014 IEEE Eighth International Conference on Self-Adaptive and Self-Organizing Systems (SASO 2014), London, UK},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2014},
   doi = {10.1109/SASO.2014.12},
   isbn = {978-1-4799-5367-7},
   keywords = {artificial intelligence; distributive justice; electronic institution; fairness; multi-agent system; allocation},
   language = {Englisch},
   cr-category = {I.2.11 Distributed Artificial Intelligence},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-55/INPROC-2014-55.pdf,     http://dx.doi.org/10.1109/SASO.2014.12},
   contact = {thomas.kohler@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Resource allocation problems are an important part of many distributed autonomous systems. In sensor networks, they determine which nodes get to use the communication links, in SmartGrid applications they decree which electric vehicle batteries are loaded, and in autonomous power management they select which generators produce the power required to satisfy the overall load. These cases have been considered in the literature before under the aspect of demand satisfaction: how well can distributed algorithms with local knowledge approximate the best allocation. A factor that has been ignored, however, is fairness: how fair is the resource allocation and - in extension - the distribution of revenue, wear, or recovery time. In this paper, we bring together previously disjoint approaches on dynamic distributed resource allocation and on fairness in electronic institutions. We show that fair allocations based on Ostrom's principles and on Rescher's canons of distributive justice create value in repeated resource allocations. We apply the scheme to solve the multi-objective problem of distributing load to generators fairly based on demands made by the individual generators. Our evaluation shows that a fair distribution increases satisfaction of the individual agents while reducing the hazard of optimising the problem in the short-term at the cost of long-term robustness and stability.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-55&engl=0}
}
@inproceedings {INPROC-2014-54,
   author = {Christoph Dibak and Boris Koldehofe},
   title = {{Towards Quality-aware Simulations on Mobile Devices}},
   booktitle = {Proceedings of the 44. Jahrestagung der Gesellschaft f{\"u}r Informatik e.V. (GI) (Informatik 2014)},
   publisher = {Gesellschaft f{\"u}r Informatik (GI)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Informatics (LNI)},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2014},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     G.1.8 Partial Differential Equations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-54/INPROC-2014-54.pdf,     http://www.gi.de/service/publikationen/lni},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Numerical simulations are import for analyzing Big Data and realizing applications in the Internet of Things. Running numerical simulations on mobile devices makes analyzing and reasoning about Big Data ubiquitous. However, mobile devices are limited in energy and compute resources, and connectivity to a dedicated infrastructure like a cloud cannot always be assured. Therefore, we propose to run the simulation on a distributed environment consisting of a mobile device and the cloud. This environment has a number of constraints for compute and network resources that need to be considered for providing simulation results in time and with high quality. In this paper we propose an architecture for mobile simulations and list challenges for realizing them.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-54&engl=0}
}
@inproceedings {INPROC-2014-32,
   author = {Florian Berg and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Increasing the Efficiency and Responsiveness of Mobile Applications with Preemptable Code Offloading}},
   booktitle = {Proceedings of the 3rd IEEE International Conference on Mobile Services: MS'14; Anchorage, Alaska, USA, June 27 - July 2, 2014},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {76--83},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2014},
   doi = {10.1109/MobServ.2014.20},
   keywords = {Distributed Systems, Code Offloading, Safe-points, Mobile Cloud Computing, Efficiency, Responsiveness},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-32/INPROC-2014-32.pdf,     http://dx.doi.org/10.1109/MobServ.2014.20},
   contact = {Florian.Berg@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobile applications are getting more and more sophisticated and demanding. Although the processing, memory, and storage resources of mobile devices are constantly increasing to enable such resource-demanding mobile applications, battery capacity is still the main limiting factor. To solve this problem, mobile code offloading approaches can be used to offload parts of a mobile application to remote servers and utilize the resources of cloud services. In this paper, we propose a novel code offloading approach that makes code offloading robust against communication link failures, which are still a major problem of mobile systems. To this end, we propose preemptable code offloading. It allows for interrupting the offloading process and continuing the remote execution locally after a link failure, without abandoning the complete result calculated remotely so far. The basic idea of our approach is to create safe-points of the remote execution and transmit these intermediate results back to the mobile device. After a link failure, the mobile device can now continue execution from the last transmitted safe-point. Although safe-points induce communication and energy overhead, our evaluations show that using an optimized safe-point schedule this overhead quickly pays off under link failures. Besides reducing the overall energy consumption significantly, responsiveness also benefits from safe-points by meeting given execution deadlines after link failures.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-32&engl=0}
}
@inproceedings {INPROC-2014-31,
   author = {Beate Ottenw{\"a}lder and Boris Koldehofe and Kurt Rothermel and Kirak Hong and Umakishore Ramachandran},
   title = {{RECEP: Selection-based Reuse for Distributed Complex Event Processing}},
   booktitle = {Proceedings of the 8th ACM International Conference on Distributed Event-Based Systems (DEBS 2014)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {59--70},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2014},
   doi = {10.1145/2611286.2611297},
   keywords = {mobility; complex event processing; query optimization},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-31/INPROC-2014-31.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {An appealing use case of complex event processing (CEP) systems is for mobile users to react in real-time to events in their environment, e.g., to the occurrence of a dangerous situation such as an accident. Maintaining mobile CEP systems is highly resource intensive since in many cases events need to be detected in a consumer-centric manner to ensure low latency event detection and high quality of results. In this paper we propose the RECEP system to increase the scalability of mobile CEP systems. In the presence of mobile users with partially overlapping interest, the RECEP system offers methods to efficiently reuse computations and this way reduces the resource requirements of mobile CEP. Since reuse of computations happens with respect to well defined quality metrics, RECEP can be easily tailored to specific mobile applications and maximize the resource savings for their desired quality in terms of precision and recall of the processed events from the user's environment.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-31&engl=0}
}
@inproceedings {INPROC-2014-29,
   author = {David Richard Sch{\"a}fer and Thomas Bach and Muhammad Adnan Tariq and Kurt Rothermel},
   title = {{Increasing Availability of Workflows Executing in a Pervasive Environment}},
   booktitle = {Proceedings of the 2014 IEEE International Conference on Services Computing},
   address = {Anchorage, AK, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {717--724},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2014},
   doi = {10.1109/SCC.2014.98},
   isbn = {978-1-4799-5066-9/14},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-29/INPROC-2014-29.pdf,     http://dx.doi.org/10.1109/SCC.2014.98},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Workflows have gained enormous importance to organize and manage business processes. With the recent advent of smartphones and mobile applications, traditional business process management is shifting. Now, long-running business processes (workflows) have to be executed in large-scale distributed and pervasive environments. Due to the heterogeneity and high dynamicity of such environments, they are vulnerable to frequent communication and device failures and, thus, impose new requirements on the execution of workflows. To increase the availability, we concurrently executed restructured replicas of workflows on multiple nodes. We developed techniques to generate differently structured replicas and propose a metric that identifies the set of replicas that ensures the highest availability during execution. Finally, we presented a distributed algorithm to coordinate and synchronize the concurrent execution of the identified replicas while maintaining the original workflow semantics. Our methods approximately double the availability during execution, while our generation techniques produce almost optimal replicas over a hundred times faster.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-29&engl=0}
}
@inproceedings {INPROC-2014-26,
   author = {Andreas Benzing and Boris Koldehofe and Kurt Rothermel},
   title = {{Bandwidth-Minimized Distribution of Measurements in Global Sensor Networks}},
   booktitle = {In Proceedings of the 14th IFIP International Conference on Distributed Applications and Interoperable Systems (DAIS 2014)},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {8460},
   pages = {156--170},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2014},
   doi = {10.1007/978-3-662-43352-2_13},
   keywords = {Data Streams; Global Sensor Networks; Optimization},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-26/INPROC-2014-26.pdf,     http://link.springer.com/chapter/10.1007/978-3-662-43352-2_13},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Global sensor networks (GSN) allow applications to integrate huge amounts of data using real-time streams from virtually anywhere. Queries to a GSN offer many degrees of freedom, e.g. the resolution and the geographic origin of data, and scaling optimization of data streams to many applications is highly challenging. Existing solutions hence either limit the flexibility with additional constraints or ignore the characteristics of sensor streams where data points are produced synchronously. In this paper, we present a new approach to bandwidth-minimized distribution of real-time sensor streams in a GSN. Using a distributed index structure, we partition queries for bandwidth management and quickly identify overlapping queries. Based on this information, our relay strategy determines an optimized distribution structure which minimizes traffic while being adaptive to changing conditions. Simulations show that total traffic and user perceived delay can be reduced by more than 50\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-26&engl=0}
}
@inproceedings {INPROC-2014-03,
   author = {Damian Philipp and Patrick Baier and Christoph Dibak and Frank D{\"u}rr and Kurt Rothermel and Susanne Becker and Michael Peter and Dieter Fritsch},
   title = {{MapGENIE: Grammar-enhanced Indoor Map Construction from Crowd-sourced Data}},
   booktitle = {Proceedings of the 12th IEEE International Conference on Pervasive Computing and Communications (PerCom 2014)},
   address = {Budapest, Hungary},
   publisher = {IEEE Computer Society Conference Publishing Services},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {139--147},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2014},
   doi = {10.1109/PerCom.2014.6813954},
   keywords = {Public Sensing; Opportunistic Sensing; Indoor Mapping; Map Reconstruction; IMU; Grammar},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2014-03/INPROC-2014-03.pdf,     http://dx.doi.org/10.1109/PerCom.2014.6813954},
   contact = {damian.philipp@ipvs.uni-stuttgart.de patrick.baier@ipvs.uni-stuttgart.de christoph.dibak@ipvs.uni-stuttgart.de frank.duerr@ipvs.uni-stuttgart.de susanne.becker@ifp.uni-stuttgart.de michael.peter@ifp.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {While location-based services are already well established in outdoor scenarios, they are still not available in indoor environments. The reason for this can be found in two open problems: First, there is still no off-the-shelf indoor positioning system for mobile devices and, second, indoor maps are not publicly available for most buildings. While there is an extensive body of work on the first problem, the efficient creation of indoor maps remains an open challenge. We tackle the indoor mapping challenge in our MapGENIE approach that automatically derives indoor maps from traces collected by pedestrians moving around in a building. Since the trace data is collected in the background from the pedestrians' mobile devices, MapGENIE avoids the labor-intensive task of traditional indoor map creation and increases the efficiency of indoor mapping. To enhance the map building process, MapGENIE leverages exterior information about the building and uses grammars to encode structural information about the building. Hence, in contrast to existing work, our approach works without any user interaction and only needs a small amount of traces to derive the indoor map of a building. To demonstrate the performance of MapGENIE, we implemented our system using Android and a foot-mounted IMU to collect traces from volunteers. We show that using our grammar approach, compared to a purely trace-based approach we can identify up to four times as many rooms in a building while at the same time achieving a consistently lower error in the size of detected rooms.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2014-03&engl=0}
}
@inproceedings {INPROC-2013-67,
   author = {Simon Gansel and Stephan Schnitzer and Frank D{\"u}rr and Kurt Rothermel and Christian Maih{\"o}fer},
   title = {{Towards Virtualization Concepts for Novel Automotive HMI Systems}},
   booktitle = {Proceedings of 4th IFIP TC 10 International Embedded Systems Symposium, IESS 2013, Paderborn, Germany, June 17-19, 2013.},
   publisher = {Springer Berlin Heidelberg},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Embedded Systems: Design, Analysis and Verification},
   volume = {403},
   pages = {193--204},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   isbn = {978-3-642-38853-8},
   isbn = {10.1007/978-3-642-38853-8_18},
   keywords = {Virtualization; Automotive HMI},
   language = {Englisch},
   cr-category = {H.5.2 Information Interfaces and Presentation User Interfaces,     J.7 Computers in Other Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-67/INPROC-2013-67.pdf,     http://link.springer.com/chapter/10.1007%2F978-3-642-38853-8_18},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many innovations in the automotive industry are based on electronics and software, which has led to a steady increase of electronic control units (ECU) in cars. This brought up serious scalability and complexity issues in terms of cost, installation space, and energy consumption. In order to tackle these problems, there is a strong interest to consolidate ECUs using virtualization technologies. However, current efforts largely neglect legal constraints and certification issues and the resulting technical requirements. In this paper, we focus on the consolidation of graphics hardware through virtualization, which received a lot of interest in the car industry due to the growing relevance of HMI systems such as head unit and instrument cluster in modern cars. First, we investigate relevant ISO standards and legal requirements and derive seven technical requirements for a virtualized automotive HMI system. Based on these requirements, we present the concept for a Virtualized Automotive Graphics System (VAGS) that allows for the consolidation of mixed-criticality graphics ECUs.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-67&engl=0}
}
@inproceedings {INPROC-2013-62,
   author = {Kirak Hong and Beate Ottenw{\"a}lder and Umakishore Ramachandran},
   title = {{Scalable Spatio-temporal Analysis on Distributed Camera Networks}},
   booktitle = {Proceedings of the 7th International Symposium on Intelligent Distributed Computing (IDC 2013)},
   publisher = {Springer International Publishing},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Studies in Computational Intelligence},
   volume = {511},
   pages = {131--140},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2013},
   doi = {10.1007/978-3-319-01571-2_16},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-62/INPROC-2013-62.pdf,     http://link.springer.com/chapter/10.1007/978-3-319-01571-2_16},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Technological advances and the low cost of sensors enable the deployment of large-scale camera networks in airports and metropolises. A well-known technique, called spatio-temporal analysis, enables detecting anomalies such as an individual entering into a restricted area without permission. Spatio-temporal analysis requires a large amount of system resources to infer locations of occupants in real-time. In particular, state update becomes a bottleneck due to computation and communication overhead to update possibly large application state. In this paper we propose a system design and mechanisms for scalable spatio-temporal analysis. We present a distributed system architecture including smart cameras and distributed worker nodes in the cloud to enable real-time spatio-temporal analysis on large-scale camera networks. Furthermore we propose and implement a couple of selective update mechanisms to further improve scalability of our system by reducing the communication cost for state update.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-62&engl=0}
}
@inproceedings {INPROC-2013-59,
   author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Protecting Movement Trajectories through Fragmentation}},
   booktitle = {Proceedings of the Tenth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous '13)},
   address = {Tokyo, Japan},
   publisher = {ICST},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2013},
   keywords = {Location based applications; position sharing; privacy},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-59/INPROC-2013-59.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Location-based applications (LBAs) like geo-social networks, points of interest finders, and real-time traffic monitoring applications have entered people's daily life. Advanced LBAs rely on location services (LSs) managing movement trajectories of multiple users in a scalable fashion. However, exposing trajectory information raises user privacy concerns, in particular if LSs are non-trusted. For instance, an attacker compromising an LS can use the retrieved user trajectory for stalking, mugging, or to trace user movement. To limit the misuse of trajectory data, we present a new approach for the secure management of trajectories on non-trusted servers. Instead of providing the complete trajectory of a user to a single LS, we split up the trajectory into a set of fragments and distribute the fragments among LSs of different providers. By distributing fragments, we avoid a single point of failure in case of compromised LSs, while different LBAs can still reconstruct the trajectory based on user-defined access rights. In our evaluation, we show the effectiveness of our approach by using real world trajectories and realistic attackers using map knowledge and statistical information to predict and reconstruct the user's movement. Location management, fragmentation, trajectories, privacy},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-59&engl=0}
}
@inproceedings {INPROC-2013-57,
   author = {Susanne Becker and Michael Peter and Dieter Fritsch and Damian Philipp and Patrick Baier and Christoph Dibak},
   title = {{Combined grammar for the modeling of building interiors}},
   booktitle = {ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences},
   address = {Kapstadt, S{\"u}dafrika},
   publisher = {International Society for Photogrammetry and Remote Sensing},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {ISPRS Acquisition and Modelling of Indoor and Enclosed Environments},
   volume = {II-4/W1},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2013},
   keywords = {Public Sensing; Opportunistic Sensing; Smartphone; Indoor; Mapping},
   language = {Deutsch},
   cr-category = {J.5 Arts and Humanities,     C.2.4 Distributed Systems},
   contact = {Susanne Becker susanne.becker@ifp.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {As spatial grammars have proven successful and efficient to deliver LoD3 models, the next challenge is their extension to indoor applications, leading to LoD4 models. Therefore, a combined indoor grammar for the automatic generation of indoor models from erroneous and incomplete observation data is presented. In building interiors where inaccurate observation data is available, the grammar can be used to make the reconstruction process robust, and verify the reconstructed geometries. In unobserved building interiors, the grammar can generate hypotheses about possible indoor geometries matching the style of the rest of the building. The grammar combines concepts from L-systems and split grammars. It is designed in such way that it can be derived from observation data fully automatically. Thus, manual predefinitions of the grammar rules usually required to tune the grammar to a specific building style, become obsolete. The potential benefit of using our grammar as support for indoor modeling is evaluated based on an example where the grammar has been applied to automatically generate an indoor model from erroneous and incomplete traces gathered by foot-mounted MEMS/IMU positioning systems.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-57&engl=0}
}
@inproceedings {INPROC-2013-52,
   author = {Damian Philipp and Jaroslaw Stachowiak and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Model-Driven Public Sensing in Sparse Networks}},
   booktitle = {Proceedings of the 10th International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {LNCS},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2013},
   keywords = {model-driven; energy optimization; public sensing; opportunistic sensing; adaptive algorithm; mobility},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-52/INPROC-2013-52.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Public Sensing (PS) is a recent trend for building large-scale sensor data acquisition systems using commodity smartphones. Limiting the energy drain on participating devices is a major challenge for PS, as otherwise people will stop sharing their resources with the PS system. Existing solutions for limiting the energy drain through model-driven optimizations are limited to dense networks where there is a high probability for every point of interest to be covered by a smartphone. In this work, we present an adaptive model-driven PS system that deals with both dense and sparse networks. Our evaluations show that this approach improves data quality by up to 41 percentage points while enabling the system to run with a greatly reduced number of participating smartphones. Furthermore, we can save up to 81\% of energy for communication and sensing while providing data matching an error bound of 1°C up to 96\% of the time.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-52&engl=0}
}
@inproceedings {INPROC-2013-51,
   author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Speed Protection Algorithms for Privacy-aware Location Management}},
   booktitle = {Proceedings of the IEEE 9th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2013).},
   address = {Lyon, France},
   publisher = {IEEE Xplore},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {355--362},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2013},
   keywords = {Location-based applications; location-based services; speed protection; movement trajectory; location management; location privacy},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-51/INPROC-2013-51.pdf,     www.ieeexplore.ieee.org,     www.PriLoc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Nowadays, millions of users share their complete movement trajectory online when using real-time traffic monitoring applications, pay-as-you-drive insurances, or when sharing their last road trip with friends. However, many users still hesitate to use location-based applications as they are not willing to reveal, for instance, their driving behavior or the occurrence of a speeding violation. Therefore, we present novel speed protection algorithms protecting users from revealing a violation of given speed limits when using location-based applications. Our algorithms support time-based and distance-based position updates. To protect positions indicating a speeding violation, we either adjust temporal information by delaying position updates or adjust their spatial information. We evaluate our algorithms by using real world traces and show that the protected movement trajectory of the user is of high quality even after removing speeding violations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-51&engl=0}
}
@inproceedings {INPROC-2013-35,
   author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Efficient Distribution of Sensing Queries in Public Sensing Systems}},
   booktitle = {Proceedings of the 10th IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS 2013)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--9},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2013},
   language = {Deutsch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-35/INPROC-2013-35.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The advent of mobile phones paved the way for a new paradigm for gathering sensor data termed Public Sensing (PS). PS uses built-in sensors of mobile devices to opportunistically gather sensor data. For instance, the microphones of a crowd of mobile phones can be used to capture sound samples, which can be used to construct a city noise map. A great challenge of PS is to reduce the energy consumption of mobile devices since otherwise users might not be willing to participate. One crucial part in the overall power consumption is the energy required for the communication between the mobile devices and the infrastructure. In particular, the communication required for sending sensing queries to mobile devices has been largely neglected in the related work so far. Therefore, in this paper, we address the problem of minimizing communication costs for the distribution of sensing queries. While existing systems simply broadcast sensing queries to all devices, we use a selective strategy by addressing only a subset of devices. In order not to negatively affect the quality of sensing w.r.t. completeness, this subset is carefully chosen based on a probabilistic sensing model that defines the probability of mobile devices to successfully perform a given sensing query. Our evaluations show that with our optimized sensing query distribution, the energy consumption can be reduced by more than 70\% without significantly reducing the quality of sensing.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-35&engl=0}
}
@inproceedings {INPROC-2013-33,
   author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Opportunistic Position Update Protocols for Mobile Devices}},
   booktitle = {Proceedings of the International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp 2013)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--9},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2013},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-33/INPROC-2013-33.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many location-based applications such as geo-social networks rely on location services storing mobile object positions. To update positions on location servers, position update protocols are used. On the one hand, these protocols decide when an update has to be sent to ensure a certain quality of position information. On the other hand, they try to minimize the energy consumption of the mobile device by reducing communication to a minimum. In this paper, we show how to improve the energy efficiency of different update protocols by taking the energy characteristics of the mobile network interface into account. In particular, we show that the energy consumption can be reduced on average by 70\% using an opportunistic update strategy sending position updates together with messages of other applications. We present a Markov model to predict the arrival of messages and an online optimization algorithm calculating an optimized schedule to send position updates.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-33&engl=0}
}
@inproceedings {INPROC-2013-31,
   author = {Kirak Hong and David Lillethun and Umakishore Ramachandran and Beate Ottenw{\"a}lder and Boris Koldehofe},
   title = {{Mobile Fog: A Programming Model for Large-Scale Applications on the Internet of Things}},
   booktitle = {Proceedings of the 2nd MCC Workshop on Mobile Cloud Computing},
   address = {Hong Kong, China},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {15--20},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2013},
   doi = {10.1145/2491266.2491270},
   keywords = {fog computing; cloud computing; programming model; Internet of Things; future Internet applications; situation awareness applications},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-31/INPROC-2013-31.pdf,     http://doi.acm.org/10.1145/2491266.2491270},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The ubiquitous deployment of mobile and sensor devices is creating a new environment, namely the Internet of Things(IoT), that enables a wide range of future Internet applications. In this work, we present Mobile Fog, a high level programming model for future Internet applications that are geospatially distributed, large-scale, and latency-sensitive. We analyze use cases for the programming model with camera network and connected vehicle applications to show the efficacy of Mobile Fog We also evaluate application performance through simulation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-31&engl=0}
}
@inproceedings {INPROC-2013-29,
   author = {Kirak Hong and David Lillethun and Umakishore Ramachandran and Beate Ottenw{\"a}lder and Boris Koldehofe},
   title = {{Opportunistic Spatio-temporal Event Processing for Mobile Situation Awareness}},
   booktitle = {Proceedings of the 7th ACM International Conference on Distributed Event-Based Systems (DEBS)},
   address = {Arlington, Texas, USA},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {195--206},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   doi = {10.1145/2488222.2488266},
   keywords = {mobility; complex event processing; situation awareness},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-29/INPROC-2013-29.pdf,     http://doi.acm.org/10.1145/2488222.2488266},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the proliferation of mobile devices and sensors, mobile situation awareness is becoming an important class of applications. The key requirement of this class of applications is low-latency processing of events stemming from sensordata in order to provide timely situational information to mobile users.To satisfy the latency requirement, we propose a spatio-temporal event processing system that uses prediction-based continuous query handling. Our system predicts future query regions for moving consumers and starts processing events early so that the live situational information is available when the consumer reaches the future location. In contrast to existing systems, our system provides timely information about a consumer's current position by hiding computation latency for processing recent events. To evaluate our system, we measure the quality of results and timeliness of live situational information with various query parameters. Our evaluation shows that we can achieve highly meaningful query results with near-zero latency in most cases.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-29&engl=0}
}
@inproceedings {INPROC-2013-28,
   author = {Beate Ottenw{\"a}lder and Boris Koldehofe and Kurt Rothermel and Umakishore Ramachandran},
   title = {{MigCEP: Operator Migration for Mobility Driven Distributed Complex Event Processing}},
   booktitle = {Proceedings of the 7th ACM International Conference on Distributed Event-Based Systems (DEBS)},
   address = {Arlington, Texas, USA},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {183--194},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   doi = {10.1145/2488222.2488265},
   keywords = {complex event processing; migration; mobility},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     E.1 Data Structures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-28/INPROC-2013-28.pdf,     http://doi.acm.org/10.1145/2488222.2488265},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {A recent trend in communication networks --- sometimes referred to as fog computing --- offers to execute computational tasks close to the access points of the networks. This enables real-time applications, like mobile Complex Event Processing (CEP), to significantly reduce end-to-end latencies and bandwidth usage. Most work studying the placement of operators in such an environment completely disregards the migration costs. However, the mobility of users requires frequent migration of operators, together with possibly large state information, to meet latency restrictions and save bandwidth in the infrastructure. This paper presents a placement and migration method for providers of infrastructures that incorporate cloud and fog resources. It ensures application-defined end-to-end latency restrictions and reduces the network utilization by planning the migration ahead of time. Furthermore, we present how the application knowledge of the CEP system can be used to improve current live migration techniques for Virtual Machines to reduce the required bandwidth during the migration. Our evaluations show that we safe up to 49\% of the network utilization with perfect knowledge about a users mobility pattern and up to 27\% of the network utilization when considering the uncertainty of those patterns.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-28&engl=0}
}
@inproceedings {INPROC-2013-27,
   author = {Boris Koldehofe and Frank D{\"u}rr and Muhammad Adnan Tariq},
   title = {{Event-based Systems Meet Software-defined Networking}},
   booktitle = {Proceedings of the 7th ACM International Conference on Distributed Event-Based Systems (DEBS)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {271--280},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   doi = {10.1145/2488222.2488270},
   keywords = {Software-defined Networking, Event-based Systems, Content-based Routing, Publish/Subscribe, Network Virtualization},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-27/INPROC-2013-27.pdf,     http://dx.doi.org/10.1145/2488222.2488270},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Software-defined networking (SDN) is a recent development in the area of communication networks with tremendous support by key players building the next generation of computer hardware and software. This development will have significant impact on how communication middleware---in particular, future distributed event-based systems---can be designed. While currently the communication middleware has no possibility to directly influence the properties of its underlying communication channels on the network layer, SDN enables communication middleware to control and flexibly adapt the forwarding of communication flows in the underlying network. In addition to the immediate implication to local area networks such as data center networks, campus networks, or company networks, novel trends like network virtualization may even support Internet-wide distributed applications to benefit from SDN in the future. This paper gives an introduction on how to utilize SDN-concepts for improving the performance of event-based middleware and to test their behavior.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-27&engl=0}
}
@inproceedings {INPROC-2013-26,
   author = {Boris Koldehofe and Ruben Mayer and Umakishore Ramachandran and Kurt Rothermel and Marco V{\"o}lz},
   title = {{Rollback-Recovery without Checkpoints in Distributed Event Processing Systems}},
   booktitle = {Proceedings of the 7th ACM International Conference on Distributed Event-Based Systems (DEBS)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {27--38},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   doi = {10.1145/2488222.2488259},
   keywords = {Reliability; Recovery; Complex Event Processing},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-26/INPROC-2013-26.pdf,     http://dx.doi.org/10.1145/2488222.2488259},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Reliability is of critical importance to many applications involving distributed event processing systems. Especially the use of stateful operators makes it challenging to provide efficient recovery from failures and to ensure consistent event streams. Even during failure-free execution, state-of-the-art methods for achieving reliability incur significant overhead at run-time concerning computational resources, event traffic, and event detection time. This paper proposes a novel method for rollback-recovery that allows for recovery from multiple simultaneous operator failures, but eliminates the need for persistent checkpoints. Thereby, the operator state is preserved in savepoints at points in time when its execution solely depends on the state of incoming event streams which are reproducible by predecessor operators. We propose an expressive event processing model to determine savepoints and algorithms for their coordination in a distributed operator network. Evaluations show that very low overhead at failure-free execution in comparison to other approaches is achieved.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-26&engl=0}
}
@inproceedings {INPROC-2013-23,
   author = {Muhammad Adnan Tariq and Boris Koldehofe and Kurt Rothermel},
   title = {{Efficient content-based routing with network topology inference}},
   booktitle = {Proceedings of the 7th ACM International Conference on Distributed Event-Based Systems (DEBS)},
   address = {Arlington, Texas, USA},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {51--62},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   doi = {10.1145/2488222.2488262},
   keywords = {QoS; quality of service; network inference; underlay awareness; delay; bandwidth; content-based; publish/subscribe; event-based},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-23/INPROC-2013-23.pdf,     http://doi.acm.org/10.1145/2488222.2488262},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Content-based publish/subscribe has gained high popularity for large-scale dissemination of dynamic content. Yet it is highly challenging to enable communication-efficient dissemination of content in such systems, especially in the absence of a broker infrastructure. This paper presents a novel approach that exploits the knowledge of event traffic, user subscriptions and topology of the underlying physical network to perform efficient routing in a publish/subscribe system. In particular, mechanisms are developed to discover the underlay topology among subscribers and publishers in a distributed manner. The information of the topology and the proximity between the subscribers to receive similar events is then used to construct a routing overlay with low communication cost. Our evaluations show that for internet-like topologies the proposed inference mechanisms are capable of modeling an underlay in an efficient and accurate manner. Furthermore, the approach yields a significant reduction in routing cost in comparison to the state of the art.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-23&engl=0}
}
@inproceedings {INPROC-2013-22,
   author = {Frank D{\"u}rr},
   title = {{Improving the Efficiency of Cloud Infrastructures with Elastic Tandem Machines}},
   booktitle = {Proceedings of the 6th International Conference on Cloud Computing (Cloud 2013)},
   address = {Santa Clara, CA, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2013},
   keywords = {cloud computing; infrastructure as a service; efficiency; energy, elasticity; scaling; system on a chip; software-defined networking; green computing},
   language = {Englisch},
   cr-category = {C.2.3 Network Operations,     C.2.4 Distributed Systems,     C.2.1 Network Architecture and Design,     C.4 Performance of Systems,     C.5 Computer System Implementation,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-22/INPROC-2013-22.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we propose a concept for improving the energy efficiency and resource utilization of cloud infrastructures by combining the benefits of heterogeneous machine instances. The basic idea is to integrate low-power system on a chip (SoC) machines and high-power virtual machine instances into so-called Elastic Tandem Machine Instances (ETMI). The low-power machine serves low load and is always running to ensure the availability of the ETMI. When load rises, the ETMI scales up automatically by starting the high-power instance and handing over traffic to it. For the non-disruptive transition from low-power to high-power machines and vice versa, we present a handover mechanism based on software-defined networking technologies. Our evaluations show the applicability of low-power SoC machines to serve low load efficiently as well as the desired scalability properties of ETMIs.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-22&engl=0}
}
@inproceedings {INPROC-2013-04,
   author = {Damian Philipp and Jaroslaw Stachowiak and Patrick Alt and Frank D{\"u}rr and Kurt Rothermel},
   title = {{DrOPS: Model-Driven Optimization for Public Sensing Systems}},
   booktitle = {2013 IEEE International Conference on Pervasive Computing and Communications (PerCom 2013)},
   address = {San Diego, CA, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {185--192},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2013},
   doi = {10.1109/PerCom.2013.6526731},
   keywords = {Data acquisition; Distributed computing; Wireless sensor networks; Public Sensing; Opportunistic Sensing; Smartphone; Model-Driven Data Acquisition; Quality aware; Adaptive, autonomic and context-aware computing; Energy-efficient and green pervasive computing; Innovative pervasive computing applications; Pervasive opportunistic communications and applications; Participatory, opportunistic and social sensing; Sensors and RFID in pervasive systems; Smart devices and intelligent environments},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-04/INPROC-2013-04.pdf,     http://www.comnsense.de,     http://dx.doi.org/10.1109/PerCom.2013.6526731},
   contact = {Damian Philipp damian.philipp@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The proliferation of modern smartphones has given rise to Public Sensing, a new paradigm for data acquisition systems utilizing smartphones of mobile participants. In this paper, we present DrOPS, a system for improving the efficiency of data acquisition in Public Sensing systems. DrOPS utilizes a model-driven approach, where the number of required readings from mobile smartphones is reduced by inferring readings from the model. Furthermore, the model can be used to infer readings for positions where no sensor is available. The model is directly constructed from the observed phenomenon in an online fashion. Using such models together with a client-specified quality bound, we can significantly reduce the effort for data acquisition while still reporting data of required quality to the client. To this effect, we develop a set of online learning and control algorithms to create and validate the model of the observed phenomenon and present a sensing task execution system utilizing our algorithms in this paper. Our evaluations show that we obtain models in a matter of just hours or even minutes. Using the model-driven approach for optimizing the data acquisition, we can save up to 80\% of energy for communication and provide inferred temperature readings for uncovered positions matching an error-bound of 1°C up to 100\% of the time.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-04&engl=0}
}
@inproceedings {INPROC-2013-01,
   author = {Bj{\"o}rn Schilling and Boris Koldehofe and Kurt Rothermel and Umakishore Ramachandran},
   title = {{Access Policy Consolidation for Complex Event Processing}},
   booktitle = {IEEE Conference on Networked Systems (NetSys)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {92--101},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2013},
   doi = {10.1109/NetSys.2013.18},
   keywords = {Event processing; Complex event processing; CEP; Security; Access Control; Bayesian network},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2013-01/INPROC-2013-01.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In distributed complex event processing, event streams are processed over a chain of subsequent operators. For large-scale applications like a logistic chain these operators may be hosted by different entities and thus are spread over different security domains. Current approaches for complex event processing cannot preserve the privacy of an operator’s incoming event streams. An adversary may infer the original input stream from its legally received event streams. In this paper we present a fine-grained access management for complex event processing. We show how to enforce privacy of events throughout the chain of dependent operators by specifying appropriate access policies and proposing an algorithm for policy consolidation. Furthermore, we introduce the calculation of obfuscation achieved in a correlation step. This allows us to ignore access requirements once a sufficient obfuscation level has been achieved, the proposed algorithms is capable to reduce the required overhead in the enforcement of access policies. We prove correctness and evaluate the cost in establishing policy consolidation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2013-01&engl=0}
}
@inproceedings {INPROC-2012-49,
   author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Efficient Position Sharing for Location Privacy using Binary Space Partitioning}},
   booktitle = {Proceedings of the Ninth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous '12)},
   address = {Beijing, People's Republic of China},
   publisher = {ICST},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2012},
   keywords = {Position Sharing; Location Privacy; Location Based Applications; Privacy},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-49/INPROC-2012-49.pdf,     http://www.priloc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Millions of users use location-based applications (LBAs) to share their positions with friends, request information from points of interest finders, or get notifications from event finders, etc. Such LBAs are typically based on location servers (LSs) managing mobile object positions in a scalable fashion. However, storing precise user positions on LSs raises privacy concerns, in particular, if LS providers are non-trusted. To solve this problem, we present PShare-BSP, a novel approach for the secure management of private user positions on non-trusted LSs. PShare-BSP splits up precise user positions into position shares and distributes them to different LSs of different providers. Thus, a compromised provider only reveals user positions with degraded precision. Nevertheless, LBAs can combine several shares from different LSs to increase their precision. PShare-BSP improves on our previous position sharing approaches: It uses a deterministic share generation approach based on binary space partitioning to avoid probabilistic attacks based, for instance, on Monte Carlo simulations. Moreover, it significantly decreases the computational complexity and increases the efficiency by reducing the update costs for succeeding position updates.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-49&engl=0}
}
@inproceedings {INPROC-2012-41,
   author = {Boris Koldehofe and Frank D{\"u}rr and Muhammad Adnan Tariq and Kurt Rothermel},
   title = {{The Power of Software-defined Networking: Line-rate Content-based Routing Using OpenFlow}},
   booktitle = {Proceedings of the 7th MW4NG Workshop of the 13th International Middleware Conference},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Workshop-Beitrag},
   month = {Dezember},
   year = {2012},
   doi = {10.1145/2405178.2405181},
   keywords = {Content-Based Routing; Publish/Subscribe; Software Defined Networking; SDN; Network Virtualization},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-41/INPROC-2012-41.pdf,     http://doi.acm.org/10.1145/2405178.2405181},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {A lot of research effort has been invested to support efficient content-based routing. Nevertheless, practitioners often fall back to far less expressive communication paradigms like multicast groups. The benefits of content-based routing in minimizing bandwidth consumption are often rendered useless by simpler communication paradigms that rely on line-rate processing of data packets at the switches of the network providers. Contrary content-based routing protocols face the inherent overhead in matching the content of events against subscriptions leading to far lower throughput rates and higher end-to-end delays. However, recent trends in networking such as software defined networking in combination with network virtualization have tremendous potential to change the picture. In our opinion this will significantly increase acceptance of sophisticated middleware like content-based routing in the future. To support our claims we outline in this paper a reference architecture that may be used to build middleware for Future Internet applications. Furthermore, we provide a solution for realizing content-based routing at line-rate relying on this reference architecture and illustrate research problems that need to be addressed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-41&engl=0}
}
@inproceedings {INPROC-2012-40,
   author = {Stephan Schnitzer and Hugo Miranda and Boris Koldehofe},
   title = {{Content Routing Algorithms to Support Publish/Subscribe in Mobile Ad Hoc Networks}},
   booktitle = {Proceedings of the 5th IEEE Workshop on Architectures, Services and Applications for the Next Generation Internet},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Workshop-Beitrag},
   month = {Oktober},
   year = {2012},
   keywords = {MANET; TPSR; Ad Hoc; Wireless Routing},
   language = {Deutsch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software,     C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-40/INPROC-2012-40.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobile Ad Hoc Networks (MANETs) allow communication between moving nodes without using infrastructure like access points, stationary routers or GPS. This offers new communication opportunities, especially in challenging environments. To communicate in MANETs we often need routing functionality, which usually provides unicast-based best effort packet delivery. Publish/Subscribe (Pub/Sub) is a well known and powerful paradigm that provides higher expressiveness than unicast routing. It decouples senders from receivers and allows information exchange between network nodes that offer certain data (called publishers) and nodes that declare their interest in data of some pattern (called subscribers). Especially in MANET applications, Pub/Sub provides useful functionality to support realistic scenarios and novel applications. This paper proposes a new algorithm called TPSR, tailored to efficiently support Pub/Sub in MANETs. It is based mainly on two principles: i) it uses the dissemination of subscriptions to create source routes; and ii) it uses the signal strength messages are received with, to optimize routes in terms of striking a good balance between long routes and fragile routes. Simulations based on ns-2 demonstrate its performance, in comparison with flooding and unicast-based solutions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-40&engl=0}
}
@inproceedings {INPROC-2012-34,
   author = {Klaus Herrmann and Daniel Fischer and Damian Philipp},
   title = {{Resource Management for Public Sensing}},
   booktitle = {Activity Context Representation: Techniques and Languages},
   editor = {Workshop Chair Lokendra Shastri},
   address = {Toronto, Canada},
   publisher = {Online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {32--39},
   type = {Workshop-Beitrag},
   month = {Juli},
   year = {2012},
   keywords = {Resource Management; Public Sensing; Ad-Hoc Routing},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-34/INPROC-2012-34.pdf,     http://activitycontext.org/wp-content/uploads/2012/07/AAAI12_W12-05_TechnicalReport_ActivityContextRepresentation.pdf},
   contact = {klaus.herrmann@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Public sensing is a new research area in the fields of wireless sensor networks and mobile computing. It leverages the mobile sensors and system resources readily available in mobile phones to execute sensing tasks. In order to plan, execute and adapt large-scale sensing tasks, applications need to query for the available resources, e.g. the density of certain sensors. We investigate how such information can be provided, and we propose a resource manager for public sensing. Our primary goal is to minimize the energy consumed by the mobile devices to make public sensing feasible without disturbing users. We propose a cluster-based protocol for collecting local views of the resource state using local ad-hoc communication since this is much more energy-efficient than long-range (e.g. cellular) communication. We compare our solution to a standard approach where mobile devices communicate their resource states using the cellular phone network. We show that 65\% of the energy is saved and the communication load on the infrastructure is reduced by 90\% while an average delivery ratio of 93\% is retained.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-34&engl=0}
}
@inproceedings {INPROC-2012-30,
   author = {Ben W. Carabelli and Andreas Benzing and Georg Seyboth and Rainer Blind and Mathias B{\"u}rger and Frank D{\"u}rr and Boris Koldehofe and Kurt Rothermel and Frank Allg{\"o}wer},
   title = {{Exact Convex Formulations of Network-Oriented Optimal Operator Placement}},
   booktitle = {Proceedings of the 51st IEEE Conference on Decision and Control (CDC2012)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {3777--3782},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2012},
   doi = {10.1109/CDC.2012.6426790},
   keywords = {Optimization; Computer networks; Sensor networks},
   language = {Englisch},
   cr-category = {G.1.6 Numerical Analysis Optimization},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-30/INPROC-2012-30.pdf,     http://dx.doi.org/10.1109/CDC.2012.6426790},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Data processing tasks are increasingly spread across the internet to account for the spatially distributed nature of many data sources. In order to use network resources efficiently, subtasks need to be distributed in the network so data can be filtered close to the data sources. Previous approaches to this operator placement problem relied on various heuristics to constrain the complexity of the problem. In this paper, we propose two generic integer constrained problem formulations: a topology aware version which provides a placement including the specific network links as well as an end-to-end delay aware version which relies on the routing capabilities of the network. A linear programming relaxation for both versions is provided which allows exact and efficient solution using common solvers.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-30&engl=0}
}
@inproceedings {INPROC-2012-26,
   author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
   title = {{TOMP: Opportunistic Traffic Offloading Using Movement Predictions}},
   booktitle = {Proceedings of the 37th IEEE Conference on Local Computer Networks (LCN)},
   address = {Clearwater},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2012},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-26/INPROC-2012-26.pdf,     http://www.comnsense.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Recent forecasts predict that the amount of cellular data traffic will significantly increase within the next few years. The reason for this trend is on the one hand the high growth rate of mobile Internet users and on the other hand the growing popularity of high bandwidth streaming applications. Given the fact that cellular networks (e.g. UMTS) have only limited capacity, the existing network infrastructure will soon reach its limits. As a result, the concept of traffic offloading attracts more and more attention in research since it aims at the reduction of cellular traffic by shifting it to local-area networks like Wifi. Within the last few years, some first approaches for automatically offloading cellular traffic were proposed. These approaches either assume the wide availability of publicly accessible Wifi networks or knowledge about social relations of mobile users. However, these assumptions are usually not fulfilled. To face this issue, we developed the TOMP system. TOMP implements a system to distribute data from the infrastructure to a set of mobile devices by partly shifting traffic from the cellular network to the level of inter-device communication. In contrast to the prevailing approaches, TOMP does not rely on open Wifi networks and only uses information about the position and speed of mobile device. By using predictions about the future movement of mobile users, TOMP determines devices that are most suitable targets for traffic offloading. In this paper we show by simulation that TOMP can save up to 40\% of cellular messages in comparison to a typical cellular network.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-26&engl=0}
}
@inproceedings {INPROC-2012-20,
   author = {Boris Koldehofe and Beate Ottenw{\"a}lder and Kurt Rothermel and Umakishore Ramachandran},
   title = {{Moving Range Queries in Distributed Complex Event Processing}},
   booktitle = {Proceedings of the 6th ACM International Conference on Distributed Event-Based Systems (DEBS).},
   address = {Berlin},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {201--212},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2012},
   doi = {10.1145/2335484.2335507},
   keywords = {Complex Event Processing; Event-based systems; Moving range queries},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-20/INPROC-2012-20.pdf,     http://doi.acm.org/10.1145/2335484.2335507},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Up to now correlations in complex event processing (CEP) systems are detected by a well defined set of operators whose configuration is determined ahead of deployment time. Although CEP operators involve location specific attributes, state of the art systems are heavily constraint in detecting situations where the interest in a situation changes dependent on the consumer's location, e.g., with the movement of mobile devices. This paper adopts the concept of range queries to CEP systems. We propose a mobility-aware event delivery semantic and present a corresponding execution model that accounts for mobility driven selection of primary event streams to the CEP system. By utilizing the properties of this execution model we derive an algorithm that establishes low cost and coordinated reconfiguration of CEP operators in a distributed system. The algorithm minimizes the amount of information that needs to be streamed between operators and avoids additional delays as a result of a reconfiguration of CEP operators. We present an analysis of the algorithm's properties and evaluate the efficiency of the proposed reconfiguration algorithm.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-20&engl=0}
}
@inproceedings {INPROC-2012-17,
   author = {Muhammad Adnan Tariq and Boris Koldehofe and Gerald. G Koch and Kurt Rothermel},
   title = {{Distributed spectral cluster management: A method for building dynamic publish/subscribe systems}},
   booktitle = {Proceedings of the 6th ACM International Conference on Distributed Event-Based Systems (DEBS)},
   address = {Berlin, Germany},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {213--224},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2012},
   doi = {10.1145/2335484.2335508},
   keywords = {Content-based; Publish/Subscribe; Broker-less; Spectral clustering; P2P; Event-based},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-17/INPROC-2012-17.pdf,     http://doi.acm.org/10.1145/2335484.2335508},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In recent years peer-to-peer (P2P) networking has gained high popularity for large-scale content distribution. Prominent systems expect a large user base with rather diversified demands. Yet it is highly challenging to achieve scalability without sacrificing the expressiveness of queries in such systems. This paper proposes distributed spectral cluster management, an approach which adapts the techniques from spectral graph theory to work in distributed settings. The proposed approach is applied to content-based publish/subscribe to i) significantly reduce the cost for event dissemination by clustering subscribers exploiting the similarity of events, ii) preserve the expressiveness of the subscription language, and iii) perform robustly in the presence of workload variations. The evaluations analyze the accuracy of the proposed distributed spectral mechanisms and show their effectiveness to significantly reduce the efforts to disseminate events under many practical workloads.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-17&engl=0}
}
@inproceedings {INPROC-2012-13,
   author = {Stefan F{\"o}ll and Florian Berg and Klaus Herrmann and Kurt Rothermel},
   title = {{A Predictive Protocol for Mobile Context Updates with Hard Energy Constraints}},
   booktitle = {Proceedings of the 13th International Conference on Mobile Data Management (MDM 2012)},
   address = {Bengaluru, India},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {125--130},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2012},
   doi = {10.1109/MDM.2012.11},
   keywords = {mobile users; update protocols; discrete context; energy efficiency; context accuracy; contrained optimization problem, Markov decision process},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {http://dx.doi.org/10.1109/MDM.2012.11},
   contact = {stefan.foell@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {As mobile devices have become powerful sensor platforms, new applications have emerged which continuously stream mobile user context (location, activities, etc.). However, energy is a limited resource on battery-equipped mobile devices. Especially frequent transmissions of context updates over energy-expensive wireless channels drain the battery of mobile devices in an uncontrolled manner. It is a fundamental algorithmic challenge to design protocols such that users can control the energy consumption on mobile devices while, at the same time, optimizing the quality of mobile applications. To address this trade-off in the area of context update protocols, we propose a novel protocol that maximizes the context accuracy perceived by a remote consumer while guaranteeing that the consumed energy stays under a given limit. Our update protocol exploits predictions about a user's future behaviour to give priority to the most effective context updates. In our evaluation, we apply our predictive update protocol to a real-world trace of user context and show that the context accuracy is significantly increased compared to an update protocol which operates without predictions under the same energy budget.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-13&engl=0}
}
@inproceedings {INPROC-2012-07,
   author = {Pavel Skvortsov and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Map-aware Position Sharing for Location Privacy in Non-trusted Systems}},
   booktitle = {Proceedings of the 10th International Conference on Pervasive Computing (Pervasive 2012)},
   editor = {Lecture Notes in Computer Science},
   address = {Newcastle, UK},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {388--405},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2012},
   keywords = {location-based service; privacy; obfuscation; sharing; map-awareness},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-07/INPROC-2012-07.pdf,     http://www.springerlink.com/content/w682352838637308/,     http://www.priloc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many current location-based applications (LBA) such as friend finder services use information about the positions of mobile users. So-called location services (LSs) have been proposed to manage these mobile user positions efficiently. However, managing user positions raises privacy issues, in particular, if the providers of LSs are only partially trusted. Therefore, the concept of private position sharing for partially trusted systems was proposed in the literature. The basic idea of position sharing is to split the precise user position into a set of position shares of well-defined limited precision and distribute these shares among LSs of different providers. The main contributions of this paper are two extended position sharing approaches that improve the basic position sharing approach in two ways: Firstly, we reduce the predictability of share generation that allows an attacker to gain further information from a sub-set of shares to further increase the position precision. Secondly, we present a position sharing algorithm for constrained movement scenarios whereas the existing approach was tailored to open space environments. However, open space approaches are vulnerable to map-based attacks. Therefore, we present a share generation algorithm that takes map knowledge into account.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-07&engl=0}
}
@inproceedings {INPROC-2012-06,
   author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
   title = {{PShare: Position Sharing for Location Privacy based on Multi-Secret Sharing}},
   booktitle = {Proceedings of the 10th IEEE International Conference on Pervasive Computing and Communications (PerCom 2012)},
   address = {Lugano, Switzerland},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {153--161},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2012},
   keywords = {Location-based applications; privacy; position sharing; location management},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-06/INPROC-2012-06.pdf,     http://www.priloc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Location-based applications such as Facebook Places, Foursquare, or Loopt attract millions of users by implementing point of interest finders, friend finders, geosocial networking, etc. Typically, these applications act as clients to a location service such as Google Latitude or Yahoo Fire Eagle, which manage mobile object positions and ensure the scalability to provide various clients with mobile object positions. However, exposing precise user positions raises user privacy concerns, especially if location service providers are not fully trusted, and private position information could be lost, leaked, stolen, etc. To enable the secure management of private user positions on non-trusted location servers (LSs), we present novel position sharing approaches based on the concept of multi-secret sharing. Our approaches split up a precise user position into position shares, which are distributed to different LSs of different providers such that a compromised provider only reveals user positions with degraded precision. On the other hand, clients can combine several shares queried from different LSs to increase their provided precision without the need to store precise information at a single LS. We propose two position sharing approaches: PShare-SLM is the first position sharing approach presented so far for symbolic location models. For geometric location models, we present PShare-GLM, which improves existing geometric position sharing approaches[DSR11] by considering continuous position updates and by increasing the robustness against various attacks.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-06&engl=0}
}
@inproceedings {INPROC-2012-03,
   author = {Stefan F{\"o}ll and Klaus Herrmann and Kurt Rothermel},
   title = {{Energy-efficient Update Protocols for Mobile User Context}},
   booktitle = {Proceedings of the 26th IEEE International Conference on Advanced Information Networking and Applications (AINA-2012)},
   address = {Fukoka, Japan},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2012},
   keywords = {mobile users; update protocols; discrete context; energy efficiency; context accuracy},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     C.2.4 Distributed Systems},
   contact = {stefan.foell@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Nowadays, rich information about the context of mobile users is directly captured on the users' mobile phones in real-time. Especially, discrete context (e.g., the user's activity) has become highly interesting for many applications since it provides an intuitive and human-understandable description of the user's current state. However, while sensing is executed locally on the mobile device, changes of user context need to be distributed from the device to a large number of interested consumers, e.g., the friends in an online social network. This produces a large overhead for the continuous transmission of context updates and represents a serious challenge for the limited energy budget of battery-equipped mobile devices. In this paper, we propose different strategies for energy-efficient context updates. We present a number of update protocols that are characterized by an inherent trade-off between quality of context and message overhead. To this end, we investigate update criteria that allow consumers of context information to express their tolerance towards the inaccurateness of received context, and we propose update protocols that exploit this tolerance to save updates and, thus, energy. In our evaluation we analyse our update protocols based on a real-world trace of user activities and show that applications can save more than 80\% of the messages when tolerating a minor degradation of the context quality only.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-03&engl=0}
}
@inproceedings {INPROC-2012-01,
   author = {Patrick Baier and Frank D{\"u}rr and Kurt Rothermel},
   title = {{PSense: Reducing Energy Consumption in Public Sensing Systems}},
   booktitle = {Proceedings of the 26th IEEE International Conference on Advanced Information Networking and Applications (AINA-2012)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {136--143},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2012},
   doi = {10.1109/AINA.2012.33},
   keywords = {ad-hoc; mobile; public sensing},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2012-01/INPROC-2012-01.pdf,     http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6184863&isnumber=6184848,     http://www.comnsense.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Utilizing peoples' mobile devices for gathering sensor data has attracted a lot of attention within the last few years. As a result, a great variety of systems for sensing environmental phenomena like temperature or noise have been proposed. However, most of these systems do not take into account that mobile devices have only limited energy resources. For instance, an often assumed prerequisite is that mobile devices are always aware of their position. Given the fact that a position fix is a very energy consuming operation, continuous positioning would quickly drain a device's battery. Since the owners of the mobile devices will not tolerate a significant reduction of the devices' battery lifetime, such an approach is not suitable. To address this issue we present PSense, a flexible system for efficiently gathering sensor data with mobile devices. By avoiding unnecessary position fixes, PSense reduces the energy consumption of mobile devices by up to 70\% compared to existing mobile sensing approaches. This is achieved by introducing an adaptive positioning mechanism and by utilizing energy efficient short-range communication to exchange position related information.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2012-01&engl=0}
}
@inproceedings {INPROC-2011-84,
   author = {Stamatia Rizou and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Fulfilling End-to-End Latency Constraints in Large-scale Streaming Environments}},
   booktitle = {Proceedings of the 30th IEEE International Performance Computing and Communications Conference: IPCCC'11},
   publisher = {IEEE Xplore},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2011},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.2.2 Network Protocols,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-84/INPROC-2011-84.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The on-line processing of high volume data streams is a prerequisite for many modern applications relying on real-time data such as global sensor networks or multimedia streaming. In order to achieve efficient data processing and scalability w.r.t. the number of distributed data sources and applications, in-network processing of data streams in an overlay network of data processing operators has been proposed. For such stream processing overlay networks, the placement of operators onto physical hosts plays an important role for the resulting quality of service—in particular, the endto- end latency—and network load. To this end, we present an enhanced placement algorithm that minimizes the network load put onto the system by a stream processing task under userdefined delay constraints in this paper. Our algorithm finds first the optimal solution in terms of network load and then degrades this solution to find a constrained optimum. In order to reduce the overhead of the placement algorithm, we included mechanisms to reduce the search space in terms of hosts that are considered during operator placement. Our evaluations show that this approach leads to an operator placement of high quality solution while inducing communication overhead proportional only to a small percentage of the total hosts.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-84&engl=0}
}
@inproceedings {INPROC-2011-76,
   author = {Hannes Wolf and Klaus Herrmann and Kurt Rothermel},
   title = {{FlexCon – Robust Context Handling in Human-Oriented Pervasive Flows}},
   booktitle = {On the Move to Meaningful Internet Systems: OTM 2011 Confederated International Conferences: CoopIS, DOA-SVI, and ODBASE 2011, Hersonissos, Crete, Greece, October 17-21, 2011, Proceedings, Part I},
   editor = {Robert Meersman and Tharam Dillon and Pilar Herrero and Akhil Kumar and Manfred Reichert and Li Qing and Beng-Chin Ooi and Ernesto Damiani and Douglas C. Schmidt and Jules White White and Manfred Hauswirth and Pascal Hitzler and Mukesh Mohania},
   address = {Berlin/Heidelberg},
   publisher = {Springer Berlin Heidelberg},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {7044},
   pages = {236--255},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2011},
   issn = {1611-3349},
   doi = {10.1007/978-3-642-25109-2_16},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     G.3 Probability and Statistics},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-76/INPROC-2011-76.pdf,     http://www.springerlink.com/content/2245482r612336ln/},
   contact = {wolfhs@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Workflows are increasingly becoming a universal means for driving and coordinating complex processes, not only in the business world but also in areas like pervasive computing. Pervasive flows run in parallel with the user{\^a}€™s real-world actions and are synchronized using automatically collected context information about her current activities (context events). Respective workflows cannot be rigidly defined since the user needs to retain her flexibility and must not be obstructed by the workflow. However, if the order of activities is not defined until the activities are actually executed, correctly assigning the uncertain context events becomes a major challenge. We propose FlexCon {\^a}€“ a novel event assignment approach for such human-oriented workflows that is based on hybrid workflow models and Dynamic Bayesian Networks. FlexCon exploits the dependency between context events to provide more accurate information as to which events need to be consumed by which workflow activities. Our evaluations show that FlexCon improves the event accuracy on average by 54\% and the number of successful completed flows on average by 88\%. Thus, FlexCon represents a major step towards unobtrusive pervasive applications.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-76&engl=0}
}
@inproceedings {INPROC-2011-74,
   author = {Patrick Baier and Harald Weinschrott and Frank D{\"u}rr},
   title = {{Effiziente automatisierte Erstellung von Stra{\ss}enkarten}},
   booktitle = {7.GI/ITG KuVS-Fachgespr{\"a}ch. Ortsbezogene Anwendungen und Dienste.},
   editor = {Roth J{\"o}rg K{\"u}pper Axel},
   address = {Berlin},
   publisher = {Logos Verlag Berlin GmbH},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {85--92},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2011},
   isbn = {978-3-8325-2935-2},
   language = {Deutsch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.2.3 Network Operations,     C.2.4 Distributed Systems,     E.1 Data Structures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-74/INPROC-2011-74.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Das relativ junge Paradigma des Urban Sensing erm{\"o}glicht die kosteng{\"u}nstige Bereitstellung von Sensordaten, welche in diesem Umfang bisher nicht zug{\"a}nglich waren. Ein potentieller Verwendungszweck dieser Daten liegt im Bereich der Kartografie, indem von Mobilger{\"a}ten erfasste GPS-Daten genutzt werden, um Stra{\ss}enkarten automatisch zu erstellen. Dadurch kann eine Ersparnis hinsichtlich Aufwand und Kosten, im Vergleich zu konventionellen Methoden der Kartenerstellung, erzielt werden. Diese Arbeit stellt einen solchen Ansatz zur effizienten, automatisierten Erstellung von Stra{\ss}enkarten mithilfe von GPS-Sensordaten vor. Diese Daten werden dabei automatisch von Personen gesammelt, die ihre Mobilger{\"a}te wie gewohnt mit sich f{\"u}hren, zus{\"a}tzlich aber auf ihren allt{\"a}glichen Wegen GPS-Positionsinformationen erfassen, welche sie einem zentralen System zur Verf{\"u}gung stellen. Dies geschieht automatisch, ohne dass eine Interaktion dieser Personen n{\"o}tig ist. Im Gegenzug soll der Ressourcenverbrauch der teilnehmenden Mobilger{\"a}te m{\"o}glichst minimiert werden. Daher koordiniert der in dieser Arbeit vorgestellte Ansatz die Erfassung der GPS-Daten so, dass die Mobilger{\"a}te diese m{\"o}glichst nur dann erfassen, wenn sie sich in einem Gebiet befinden, welches bis zu diesem Zeitpunkt noch nicht ausreichend kartografisch erfasst wurde. Um diese gezielte Koordination der Mobilger{\"a}te zu erm{\"o}glichen, werden im Rahmen dieser Arbeit Qualit{\"a}tsmetriken f{\"u}r Geodaten vorgestellt, welche den erfassten Stra{\ss}en quantitative Gr{\"o}{\ss}en zuordnen, um so einen Vergleich dieser Daten zu erm{\"o}glichen.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-74&engl=0}
}
@inproceedings {INPROC-2011-73,
   author = {Damian Philipp and Frank D{\"u}rr and Kurt Rothermel},
   title = {{A Sensor Network Abstraction for Flexible Public Sensing Systems}},
   booktitle = {Proceedings of the 8th IEEE International Conference on Mobile Ad-Hoc and Sensor Systems: MASS'11; Valencia, Spain, October 17-22, 2011},
   editor = {IEEE Computer Society Conference Publishing Services},
   address = {Valencia},
   publisher = {IEEE Computer Society Conference Publishing Services},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {IEEE Computer Society Order Number},
   volume = {E4469},
   pages = {460--469},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2011},
   doi = {10.1109/MASS.2011.52},
   isbn = {978-0-7695-4469-4/11},
   keywords = {Public Sensing; Sensor Networks; Smartphone},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems,     C.2.5 Local and Wide-Area Networks,     C.5.3 Microcomputers},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-73/INPROC-2011-73.pdf,     http://dx.doi.org/10.1109/MASS.2011.52,     http://www.comnsense.de},
   contact = {damian.philipp@ipvs.uni-stuttgart.de, frank.duerr@ipvs.uni-stuttgart.de, kurt.rothermel@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Public Sensing is a new paradigm for developing large-scale sensor networks at low cost by utilizing mobile phones that are already surrounding us in our everyday lives. In this paper we present a sensor network abstraction layer for creating flexible public sensing systems that can execute arbitrary queries. To this effect we develop several algorithms to select mobile nodes for executing a query. These algorithms allow a user to define a trade-off between quality and efficiency of query execution by choosing an appropriate algorithm. Our evaluations show that we can achieve a 99$\backslash$\% increase in efficiency with the most efficient approaches and only about 10$\backslash$\% decrease in result quality under worst conditions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-73&engl=0}
}
@inproceedings {INPROC-2011-70,
   author = {Hannes Wolf and Jonas Palauro and Klaus Herrmann},
   title = {{Fuzzy Event Assignment for Robust Context-Aware Workflows}},
   booktitle = {Proceedings of The Fourth International Conference on Dependability (DEPEND 2011)},
   editor = {IARIA},
   address = {Nice/Saint Laurent du Var, France},
   publisher = {IARIA},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {37--42},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2011},
   isbn = {978-1-61208-149-6},
   keywords = {context-aware workflows, dependable event assignment, fuzzy logic},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     I.2.3 Deduction and Theorem Proving},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-70/INPROC-2011-70.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The dependability of any kind of context-aware pervasive system inherently relies on the ability to detect and recognize context events robustly. However, due to the inaccuracy of real-world sensors the accurate recognition and handling of context information is a fundamental problem leading to ambiguities and inconsistent behavior of applications. Adaptable Pervasive Flows (APF) are a novel workflow-based programming paradigm for pervasive applications. An APF encodes the temporal dependencies of a user’s tasks. We propose a Fuzzy Event Assignment (FEvA) algorithm that exploits this flow-knowledge to significantly improve the robustness of context-aware pervasive applications by resolving the ambiguities inherent to the context data. Our experiments show that FEvA reaches an event assignment accuracy of 78\% to 97\% and improves the performance of dealing with false positive, out-of-order events, and missed context information.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-70&engl=0}
}
@inproceedings {INPROC-2011-61,
   author = {Lars Geiger and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Adaptive Routing in a Contextcast Overlay Network}},
   booktitle = {Proceedings of the IEEE 7th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2011)},
   publisher = {IEEE Xplore},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2011},
   doi = {10.1109/WiMOB.2011.6085340},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.2.4 Distributed Systems,     C.2.6 Internetworking},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-61/INPROC-2011-61.pdf,     http://dx.doi.org/10.1109/WiMOB.2011.6085340},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Context-based communication allows for the dissemination of messages to mobile users with a specified context, i.e., at a location and with certain attribute values. This enables, e.g., a message to students on campus attending a certain class, with information about a study group for an upcoming exam. An overlay network of context-aware routers efficiently disseminate the messages to all matching receivers. Directed forwarding of such messages requires that the routers maintain knowledge about the contexts of connected users. Global knowledge, i.e., each router knowing about every user, scales poorly, though, because of the necessary updates. To overcome this challenge, a router can selectively propagate context information that actually allows its neighbors to prune a message distribution tree. In this paper, we present an approach to adaptively propagate only those user contexts that offer a reduction in overall system load. The algorithm automatically and locally adapts to the observed messages and user contexts on each node. Our solution significantly improves the scalability of the system by reducing the overall load by almost 50\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-61&engl=0}
}
@inproceedings {INPROC-2011-59,
   author = {Bilal Hameed and Jorge Minguez and Michael W{\"o}rner and Philip Hollstein and Sema Zor and Stefan Silcher and Frank D{\"u}rr and Kurt Rothermel},
   title = {{The Smart Real-Time Factory as a Product Service System}},
   booktitle = {3rd CIRP International Conference on Industrial Product Service Systems},
   address = {Braunschweig, Germany},
   publisher = {IRP},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2011},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In modern manufacturing landscape, companies are increasingly relying on product service systems i.e. bundling of products and services together in order to gain a competitive edge. In this article we present the Smart Real-Time Factory, a smart digital manufacturing environment that can transform the process of production into an informational service for the customers. The different components of the smart factory are discussed at length along with a discussion of the different services that can be offered by the smart factory.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-59&engl=0}
}
@inproceedings {INPROC-2011-51,
   author = {Patrick Baier and Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
   title = {{MapCorrect: Automatic Correction and Validation of Road Maps Using Public Sensing}},
   booktitle = {36th Annual IEEE Conference on Local Computer Networks (LCN 2011)},
   address = {Bonn, Germany},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2011},
   keywords = {ad-hoc; mobile; public sensing},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-51/INPROC-2011-51.pdf,     http://www.comnsense.de},
   contact = {patrick.baier@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the increasing proliferation of small and cheap GPS receivers, a new way of generating road maps could be witnessed over the last few years. Participatory mapping approaches like OpenStreetMap, for instance, introduced a way to generate road maps collaboratively from scratch. Nevertheless, one of the main problems of these maps is their unknown quality in terms of accuracy. To address this issue, we propose MapCorrect: An automatic map correction and validation system. MapCorrect automatically collects GPS traces from people's mobile devices to correct a given road map and validate it. Since the collection of GPS data raises concerns about the energy consumption of the participating mobile devices, we tackle this issue by introducing a selective sensing mechanism. Furthermore, we show by simulation that using this approach up to 50\% of energy on the mobile phones can be saved while not impairing the map correction and validation process at all.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-51&engl=0}
}
@inproceedings {INPROC-2011-49,
   author = {Stefan F{\"o}ll and Klaus Herrmann and Kurt Rothermel},
   title = {{PreCon - Expressive Context Prediction using Stochastic Model Checking}},
   booktitle = {Proceedings of the 8th International Conference on Ubiquitous Intelligence and Computing (UIC 2011)},
   address = {Banff, Canada},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   pages = {1--15},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2011},
   keywords = {Context Prediction, Semi-Markov Model, Stochastic Model Checking, Temporal Logic},
   language = {Deutsch},
   cr-category = {G.3 Probability and Statistics,     I.2.6 Artificial Intelligence Learning,     I.6.4 Model Validation and Analysis},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-49/INPROC-2011-49.pdf,     http://www.springerlink.com/content/xv8821301mh22473/},
   contact = {stefan.foell@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Ubiquitous systems need to determine the context of humans to deliver the right services at the right time. As the needs of humans are often coupled to their future context, the ability to predict relevant changes in a user's context is a key factor for providing intelligence and proactivity. Current context prediction systems only allow applications to query for the next user context (e.g. the user's next location). This severely limits the benefit of context prediction since these approaches cannot answer more expressive time-dependent queries (e.g. will the user enter location X within the next 10 minutes?). Neither can they handle predictions of multi-dimensional context (e.g. activity and location). We propose PreCon, a new approach to predicting multi-dimensional context. PreCon improves query expressiveness, providing clear formal semantics by applying stochastic model checking methods. PreCon is composed of three major parts: a stochastic model to represent context changes, an expressive temporal-logic query language, and stochastic algorithms for predicting context. In our evaluations, we apply PreCon to real context traces from the domain of healthcare and analyse the performance using well-known metrics from information retrieval. We show that PreCon reaches an F-score (combined precision and recall) of about 0.9 which indicates a very good performance.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-49&engl=0}
}
@inproceedings {INPROC-2011-44,
   author = {Marco V{\"o}lz and Boris Koldehofe and Kurt Rothermel},
   title = {{Supporting Strong Reliability for Distributed Complex Event Processing Systems}},
   booktitle = {Proceedings of 13th IEEE International Conference on High Performance Computing and Communications (HPCC-2011)},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {477--486},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2011},
   doi = {10.1109/HPCC.2011.69},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-44/INPROC-2011-44.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many application classes such as monitoring applications, involve processing a massive amount of data from a possibly huge number of data sources. Complex Event Processing (CEP) has evolved as the paradigm of choice to determine meaningful situations (complex events) by performing stepwise correlation over event streams. To keep up with the high scalability demands of growing input streams, recent approaches distribute event correlation over several correlation nodes. However, the distribution of event correlation severely limits the reliability of a CEP system. Already a failure of a single correlation node impacts the correctness of the final correlation result. Increasing the availability by a naive application of established replication principles introduces new problems in the context of CEP. In particular, ensuring the lossless delivery of events and the detection of duplicate events before processing them is a challenging task. In this paper, we illustrate the importance of a strong reliability semantics for CEP in the context of a monitoring application in a distributed production environment. Strong reliability ensures each complex event is detected and delivered exactly once to each application entity. We present a replication scheme which ensures strong reliability in an asynchronous system model and can be applied to an arbitrary distributed CEP system. The algorithm tolerates f simultaneous failures by introducing f additional replicas for each correlation node. We prove correctness as well as evaluate the overhead introduced by the algorithm. Results show, that the overhead scales linearly with the number of deployed replicas and the node failure rate.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-44&engl=0}
}
@inproceedings {INPROC-2011-43,
   author = {Bj{\"o}rn Schilling and Boris Koldehofe and Kurt Rothermel},
   title = {{Efficient and Distributed Rule Placement in Heavy Constraint-Driven Event Systems}},
   booktitle = {Proceedings of the 13th IEEE International Conference on High Performance Computing and Communications (HPCC-2011)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {355--364},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2011},
   doi = {10.1109/HPCC.2011.53},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-43/INPROC-2011-43.pdf,     http://dx.doi.org/10.1109/HPCC.2011.53},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Complex Event Processing (CEP) is of increasing importance in many industrial applications to integrate a huge number of events in a scalable manner. A core challenge towards scalable CEP is to efficiently distribute the rules which define how correlations between events can be detected within an event processing network. Furthermore, migration of rules is essential to adapt to changing conditions. While recently significant effort has been spent on optimizing CEP with respect to dedicated optimization goals, such as minimizing latency and bandwidth usage, there remains a fundamental gap in supporting requirements that emerge from deploying CEP over heterogeneous and independent processing environments. Heterogeneity typically imposes many constraints on the placement of rules, which increases the complexity of the underlying optimization problem and cannot be handled efficiently by existing solutions. In this paper we examine the distributed placement, migration and optimization of rules in the context of the constraint optimization problem to minimize network usage. We propose and evaluate a placement algorithm that efficiently finds valid solutions in scenarios where the solution space is heavily restricted by constraints. The algorithm operates in a decentralized way and is adaptive to dynamic changes of processing nodes, rules, and load characteristics of the event processing network. The optimization algorithm adopts techniques from simulated annealing to avoid local minima. Furthermore, the proposed rule migration policies resolve invalid placements quickly and therefore ensure high availability. The evaluations show that the proposed algorithm is able to efficiently find near optimum solutions within heavy constraint-driven network conditions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-43&engl=0}
}
@inproceedings {INPROC-2011-31,
   author = {Daniel Fischer and Stefan F{\"o}ll and Klaus Herrmann and Kurt Rothermel},
   title = {{Energy-efficient Workflow Distribution}},
   booktitle = {Proceedings of the Fifth International Conference on Communication System Software and Middleware(COMSWARE 2011)},
   address = {Verona, Italy},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2011},
   keywords = {Workflow distribution; Energy efficiency; Minimum Cut},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.4 Information Systems Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-31/INPROC-2011-31.pdf,     http://doi.acm.org/10.1145/2016551.2016553},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive computing and business process modeling are joining forces, as mobile human users shall be seamlessly integrated into business processes. This current trend gains momentum. In respective scenarios, humans use mobile devices and wireless communication technology to interact with electronic workflows that are entirely running in some powerful back-end infrastructure. However, the high degree of interaction between humans and their workflows causes a high communication overhead, which consumes a significant amount of energy on the mobile devices. This incurs a negative impact on the usability and on the efficiency of the overall business process due to rapidly drained batteries and the resulting short life-times of the devices and applications. We present an approach based on the well-known minimum-cut algorithm for reducing the costly data transmissions during workflow execution by distributing parts of a workflow to the users' devices. Our main motivation is to reduce the energy consumption on the mobile devices and, thus, avoid situations in which batteries are drained in the field, rendering the usage of mobile devices more efficient. We prove that our algorithm finds the optimal solution for a given network and a workflow. Our evaluations show that our approach decreases the energy consumed on mobile devices by 32-37\% compared to an approach where the entire workflow is executed in a central infrastructure. Thus, if mobile devices are primarily used for executing workflows (as seen in application domains like logistics and health care), one third of the energy can be saved. This either means that devices have to be charged less frequently, leading to less distraction in the business process, or that mobile device specifications can be lowered. Significant cost reductions result in both cases.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-31&engl=0}
}
@inproceedings {INPROC-2011-30,
   author = {Andreas Benzing and Boris Koldehofe and Kurt Rothermel},
   title = {{Efficient Support for Multi-Resolution Queries in Global Sensor Networks}},
   booktitle = {Proceedings of the Fifth International Conference on COMmunication System softWAre and middlewaRE: COMSWARE 2011},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2011},
   doi = {10.1145/2016551.2016562},
   keywords = {DSPS, global sensor network, indexing, query processing},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-30/INPROC-2011-30.pdf,     http://dl.acm.org/authorize?6553117},
   contact = {andreas.benzing@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Stream processing has evolved as a paradigm for efficiently sharing and integrating a massive amount of data into applications. However, the integration of globally dispersed sensor data imposes challenges in the effective utilization of the IT infrastructure that forms the global sensor network. Especially, simulations require the integration of sensor streams at widely differing spatial and temporal resolutions. For current stream processing solutions it is necessary to generate a separate data stream for each requested resolution. Therefore, these systems will suffer from high redundancy in data streams, wasting a significant amount of bandwidth and limiting their scalability. This paper presents a new approach to scalable distributed stream processing of data which stems from globally dispersed sensor networks. The approach supports applications in establishing continuous queries for sensor data at different resolutions and ensures efficient bandwidth usage of the data distribution network. Unlike existing work in the context of video stream processing which provides multiple resolutions by establishing separate channels for each resolution, this paper presents a stream processing system that can efficiently split/combine data streams in order to decrease/increase their resolution without loss in data precision. In addition the system provides mechanisms for load balancing of sensor data streams that allow efficient utilization of the bandwidth of the global sensor network.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-30&engl=0}
}
@inproceedings {INPROC-2011-22,
   author = {Andreas Grau and Klaus Herrmann and Kurt Rothermel},
   title = {{NETbalance: Reducing the Runtime of Network Emulation using Live Migration}},
   booktitle = {Proceedings of the 20th International Conference on Computer Communication Networks (ICCCN'11)},
   address = {Maui, HI, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2011},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-22/INPROC-2011-22.pdf,     http://dx.doi.org/10.1109/ICCCN.2011.6005793},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Network emulation is an efficient method for evaluating distributed applications and communication protocols by combining the benefits of real world experiments and network simulation. The process of network emulation involves the execution of connected instances of the software under test (called virtual nodes) in a controlled environment. In previous work, we introduced an approach to minimize the runtime of network emulation experiments based on prior known average resource requirements of virtual nodes. In this paper, we introduce NETbalance, a novel approach to runtime reduction for experiments with unknown or varying resource requirements. NETbalance migrates virtual nodes during an experiment to distribute the load evenly across the physical nodes, avoiding overloaded nodes and exploiting the idle resources on underloaded nodes for speeding up the experiment execution. We make the following contributions: First, we present an emulation architecture for efficiently supporting live migration of virtual nodes. Second, we propose a cost model for determining the runtime reduction achieved through the migration. Third, we introduce an algorithm for calculating placements that minimize the experiment runtime. Our evaluations of the NETbalance prototype show, that it is able to reduce the experiment runtime by up to 70\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-22&engl=0}
}
@inproceedings {INPROC-2011-19,
   author = {Christian Hiesinger and Daniel Fischer and Stefan F{\"o}ll and Herrmann Klaus and Kurt Rothermel},
   title = {{Minimizing Human Interaction Time in Workflows}},
   booktitle = {Proceedings of the Sixth International Conference on Internet and Web Applications and Services (ICIW 2011)},
   address = {St. Maarten, the Netherlands Antilles},
   publisher = {IARIA},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {22--28},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2011},
   keywords = {Workflow distribution; human interaction; pervasive workflows},
   language = {Englisch},
   cr-category = {D.2.4 Software Engineering Software/Program Verification,     H.4 Information Systems Applications},
   contact = {christian.hiesinger@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many business scenarios require humans to interact with workflows. To support humans as unobtrusively as possible in the execution of their activities, it is important to keep the interaction time experienced by humans as low as possible. The time required for such interactions is influenced by two factors: First, by the runtime of the services that are used by a workflow during an interaction. Second, by the time required to transfer data between workflow servers and services that may be distributed in a global network. We propose an algorithm that computes a suitable distribution of a workflow in such a network. The goal of our algorithm is to minimize the time required for interactions between a human and a workflow. Current approaches in the domain of workflow optimization pay little attention towards optimizing a workflow to increase the usability for humans. We show the feasibility of our approach by comparing our algorithm with two non-distributed approaches and a distributed approach which is based on a greedy algorithm and show that our algorithm outperforms these approaches.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-19&engl=0}
}
@inproceedings {INPROC-2011-11,
   author = {Frank D{\"u}rr and Pavel Skvortsov and Kurt Rothermel},
   title = {{Position Sharing for Location Privacy in Non-trusted Systems}},
   booktitle = {Proceedings of the 9th IEEE International Conference on Pervasive Computing and Communications (PerCom 2011)},
   address = {Seattle, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {189--196},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2011},
   doi = {10.1109/PERCOM.2011.5767584},
   keywords = {location-based service; privacy; obfuscation; sharing; location management},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-11/INPROC-2011-11.pdf,     http://dx.doi.org/10.1109/PERCOM.2011.5767584,     http://www.priloc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many novel location-based services (LBS) such as a friend finder service require knowledge about the positions of mobile users. Usually, location services are used to manage these positions, and for providing basic functionality like spatial range queries or spatial events to the LBS. Managing and using the positions of mobile users raises privacy issues, in particular, if the providers of LBS and location services are only partially trusted. Many different approaches for preserving a user's privacy have been proposed in the literature, e.g. location obfuscation and the k-anonymity concept. However, most of them are not suitable if both LBS and location service providers are non-trusted. In contrast to these approaches, we present a novel approach for the secure management of private position information in partially trusted system environments. The main contribution in this paper is a position sharing concept which allows for the distribution of position information (shares) of strictly limited accuracy onto several location servers of different providers. With this approach, a compromised server will only reveal information of limited accuracy. Moreover, we will show how position shares of coarse granularity from multiple location servers can be fused into information of higher precision to satisfy the accuracy requirements of different LBS.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-11&engl=0}
}
@inproceedings {INPROC-2011-10,
   author = {Harald Weinschrott and Julian Weisser and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Participatory Sensing Algorithms for Mobile Object Discovery in Urban Areas}},
   booktitle = {Proceedings of the 9th Annual IEEE International Conference on Pervasive Computing and Communications},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {128--135},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2011},
   doi = {10.1109/PERCOM.2011.5767577},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-10/INPROC-2011-10.pdf,     http://dx.doi.org/10.1109/PERCOM.2011.5767577,     http://www.comnsense.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {This paper introduces mechanisms for the automated detection of mobile objects in urban areas. Widely available devices such as mobile phones with integrated proximity sensors such as RFID readers or Bluetooth cooperatively perform sensing operations to discover mobile objects. In this paper, we propose a coverage metric for assessing the completeness of sensing that considers spatial and temporal aspects. To maximize coverage while minimizing energy consumption of mobile nodes, we propose both a centralized and a distributed coordination algorithm for selecting nodes that need to sense. Moreover, we present strategies that allow selected nodes to perform efficient sense operations. By extensive simulations, we show that distributed coordination achieves drastic energy savings of up to 63\%, while limiting the coverage loss to 13\%. Moreover, we show that the centralized algorithm loses less than 1\% coverage compared to the maximum possible coverage.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-10&engl=0}
}
@inproceedings {INPROC-2011-09,
   author = {Umakishore Ramachandran and Liviu Iftode and Rajnish Kumar and Santosh Pande and Kurt Rothermel and Boris Koldehofe},
   title = {{Large-scale Situational Awareness with Camera Networks and Multimodal Sensing}},
   booktitle = {NSF Workshop on Pervasive Computing at Scale (PeCS)},
   publisher = {online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--2},
   type = {Workshop-Beitrag},
   month = {Januar},
   year = {2011},
   keywords = {Distributed Systems},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {This white paper raises the challenges and solution approaches for dealing with large-scale media-rich infrastructures for addressing the needs of large-scale sensor-based applications, often classified as situation awareness applications, using smart surveillance as a canonical example.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-09&engl=0}
}
@inproceedings {INPROC-2011-08,
   author = {Gerald G. Koch and Andreas Benzing and Christoph P. Mayer},
   title = {{An Approach for Urban Sensing with Quality-Aware Situation Detection and Efficient Communication}},
   booktitle = {Proceedings of the Workshops der wissenschaftlichen Konferenz Kommunikation in verteilten Systemen 2011 (WowKiVS 2011); Kiel, Germany, March 11th, 2011},
   editor = {Horst Hellbr{\"u}ck and Norbert Luttenberger and Volker Turau},
   publisher = {EASST},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Electronic Communications of the EASST},
   pages = {1--10},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2011},
   issn = {1863-2122},
   keywords = {Urban sensing; Internet of Things; Complex Event Processing; CEP; Delay Tolerant Network; DTN; Distributed Diagnostic Simulation},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     C.2.4 Distributed Systems,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2011-08/INPROC-2011-08.pdf},
   contact = {gerald.koch@ipvs.uni-stuttgart.de andreas.benzing@ipvs.uni-stuttgart.de mayer@kit.edu},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Urban Sensing employs physical-world mining to create a digital model of the physical world using a large number of sensors. Handling the large amount of data generated by sensors is costly and requires energy-saving measures for sensing and sensor data transmission. Such schemes often affect data quality and message delay. However, the detection of real-world situations using Complex Event Processing on sensor data has to be dependable and timely and requires precise data. In this position paper, we propose an approach to integrate the contradicting optimization goals of energy-efficient wireless sensor networks and dependable situation detection. It separates the system into the following tiers: First, to support energy-efficiency and allow sparse, unconnected sensor networks, we exploit the mobility of people through Delay Tolerant Networking for collecting sensor data. This frees sensor nodes from energy-expensive routing. Second, we employ Diagnostic Simulation which provides data that is complete, precise and in time and therefore supports quality-aware situation detection.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2011-08&engl=0}
}
@inproceedings {INPROC-2010-81,
   author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Indexing Source Descriptions based on Defined Classes}},
   booktitle = {Proceedings of the 14th International Database Engineering and Applications Symposium (IDEAS '10). Montreal, QC, Canada. August 2010},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {245--256},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2010},
   keywords = {heterogeneous information systems; source descriptions; indexing of source descriptions; defined classes; tree-based index structure},
   language = {Englisch},
   cr-category = {H.2.5 Heterogeneous Databases,     H.3.3 Information Search and Retrieval},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-81/INPROC-2010-81.pdf,     http://doi.acm.org/10.1145/1866480.1866514},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Scaling heterogeneous information systems (HIS) to thousands of sources poses particular challenges to source discovery. It requires a powerful formalism for describing the contents of the sources in a concise manner and for formulating compatible queries as well as a suitable structure for indexing and retrieving the source descriptions efficiently. We propose an extended logic-based description formalism for large-scale HIS with structured sources and a shared ontology. The formalism refines existing approaches that describe the sources by constraints on the attribute value ranges in several ways: It allows for complex, nested descriptions based on defined classes. It supports alternative descriptions to express that a source may be discovered by different combinations of constraints. Finally, it allows to adjust between positive matching, similar to keyword-based discovery, and negative matching, as used in existing logic-based approaches. We further propose the SDC-Tree for indexing such source descriptions. To allow for efficient discovery, the SDC-Tree features multidimensional indexing capabilities for the different attributes and the IS-A hierarchy of the shared ontology, but also incorporates the existence or absence of constraints. For this purpose, it supports three different types of node split operations which exploit the expressiveness of the description formalism. Therefore, we also propose a generic split algorithm which can be used with arbitrary ontologies.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-81&engl=0}
}
@inproceedings {INPROC-2010-80,
   author = {Hannes Wolf and Klaus Herrmann and Kurt Rothermel},
   title = {{Robustness in Context-Aware Mobile Computing}},
   booktitle = {IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob'2010)},
   address = {Niagara Falls, Canada},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {46--53},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2010},
   doi = {10.1109/WIMOB.2010.5645026},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     I.5.1 Pattern Recognition Models},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-80/INPROC-2010-80.pdf,     http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5645026},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {High level context recognition and situation detection are an enabling technologies for unobtrusive mobile computing systems. Significant progress has been made in processing and managing context information, leading to sophisticated frameworks, middlewares, and algorithms. Despite great improvements, context aware systems still require a significantly increased recognition accuracy for high-level context information on uncertain sensor data to enable the robust execution of context-aware applications. Recently Adaptable Pervasive Workflows (APF)s have been presented as innovative programming paradigm for mobile context-aware applications. We propose a novel Flow Context System (FlowCon) that builds upon APFs. FlowCon uses structural information from the APF to increase accuracy of uncertain high-level context information up to 49$\backslash$\%. This way we make an important step to enable robust execution of mobile context-aware applications.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-80&engl=0}
}
@inproceedings {INPROC-2010-78,
   author = {A. Bucchiarone and A. Marconi and M. Pistore and S. F{\"o}ll and K. Herrmann and C. Hiesinger and S. Marinovic},
   title = {{An Overall Process for Self-Adaptive Pervasive Systems}},
   booktitle = {Proceedings of the Second International Conference on Adaptive and Self-adaptive Systems and Applications : ADAPTIVE 2010 ; Lisbon, Portugal, November 21-26, 2010},
   publisher = {Elsevier},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2010},
   language = {Deutsch},
   cr-category = {D.2.9 Software Engineering Management,     D.2.11 Software Engineering Software Architectures},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Self-adaptive pervasive systems often implement adaptation in a centralised manner, where one component holds all the necessary knowledge to identify when and how the system needs to adapt. In self-adaptive pervasive systems, composed of autonomous components with different authorities (such as security, distribution, etc.), this approach cannot be implemented as composing a centralised knowledge is not feasible and it also obstructs the system's ability to dynamically change its components. A simple alternative would be to allow each component to adapt independently but this can quickly give rise to conflicts, race conditions and oscillations between multiple independent adaptations. To avoid these problems, we propose to coordinate individual adaptations so that each component's adaptation goals are satisfied. Each component proposes an adaptation which is reviewed by other components who may propose their own adaptations that they may need to do. This continues until a complete adaptation plan is agreed upon. In cases where certain individual adaptations conflict with some components' goals, components are instructed to seek alternative proposals. The Adaptation Manager component is in charge of the negotiation process and it also has the authority to resolve certain conflicts between adaptations. Our approach is evaluated in the context of pervasive workflow systems where the failure probability and execution times are assessed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-78&engl=0}
}
@inproceedings {INPROC-2010-71,
   author = {Bilal Hameed and Imran Ahmed Khan and Frank D{\"u}rr and Kurt Rothermel},
   title = {{An RFID Based Consistency Management Framework for Production Monitoring In a Smart Real-Time Factory}},
   booktitle = {Proceedings of 2010 Internet of Things Conference (To Appear).},
   address = {Tokyo, Japan},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks,     C.2.1 Network Architecture and Design},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The use of RFID devices for real-time production monitoring in modern factories is impeded by the inherent unreliability of RFID devices. In this paper we present a consistency stack that conceptually divides the different consistency issues in production monitoring into separate layers. In addition to this we have built a consistency management framework to ensure consistent real-time production monitoring, using unreliable RFID devices. In detail, we deal with the problem of detecting object sequences by a set of unreliable RFID readers that are installed along production lines. We propose a probabilistic sequence detection algorithm that assigns probabilities to objects detected by RFID devices and provides probabilistic guarantees regarding the real-time sequences of objects on the production lines.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-71&engl=0}
}
@inproceedings {INPROC-2010-69,
   author = {Andreas Benzing and Boris Koldehofe and Marco V{\"o}lz and Kurt Rothermel},
   title = {{Multilevel Predictions for the Aggregation of Data in Global Sensor Networks}},
   booktitle = {Proceedings of the 14th IEEE/ACM International Symposium on Distributed Simulation and Real Time Applications},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {169--178},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2010},
   keywords = {Global Sensor Networks; Distributed Stream Processing; Predictors},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-69/INPROC-2010-69.pdf,     http://ieeexplore.ieee.org/search/srchabstract.jsp?tp=&arnumber=5636734},
   contact = {andreas.benzing@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Real-time simulations are one challenging application domain that is expected to introduce high requirements to global sensor applications. Besides having hard constraints on latency bounds at which data needs to be processed, simulation applications will impose high requirements with respect to available bandwidth. Predictors, originally introduced in the domain of wireless sensor networks for energy saving, are one appealing solution to provide real-time estimates and at the same time significantly reduce the data rates. While in the setting of wireless sensor networks many prediction models have been analyzed, their behavior and use is unclear when applied to distributed data streams where aggregation results are typically processed over multilevel hierarchies. In the context of weather simulations, we propose a distributed R-Tree-based aggregation algorithm that allows for efficient reuse of aggregate queries. In the setting of real temperature readings taken from weather stations during one month, we study the trade-off between updates of the prediction model and the precision of the predicted values. Our evaluations indicate that even in situations where complex prediction models are expected to perform best, simple prediction models give higher benefits with respect to saving bandwidth while providing similar data accuracy.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-69&engl=0}
}
@inproceedings {INPROC-2010-65,
   author = {Daniel Fischer and Klaus Herrmann and Kurt Rothermel},
   title = {{GeSoMo - A General Social Mobility Model for Delay Tolerant Networks}},
   booktitle = {Proceedings of the 7th IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS '10)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--9},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2010},
   language = {Deutsch},
   cr-category = {C.2.1 Network Architecture and Design,     C.4 Performance of Systems,     I.6.0 Simulation and Modeling General},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Simulation is a fundamental means for evaluating mobile applications based on ad-hoc networks. This has led to the design of a large number of mobility models for simulating realistic user movement under physical constraints (obstacles, acceleration, inertia etc.). In recent years, the new breed of social mobility models (SMMs) has risen. These SMMs model the $\backslash$emph{social aspects of human mobility}, i.e. which users meet, when and how often. Such information is indispensable for the simulation of a wide range of socially-aware communication protocols mostly based on delay-tolerant networks, including opportunistic ad-hoc routing and data dissemination systems. Each SMM needs a model of the relations between a set of relevant people (called social network model -- SNM) in order to simulate their mobility. Existing SMMs lack flexibility since each of them is implicitly restricted to a specific, simplifying SNM. We present GeSoMo, a new SMM that separates the core mobility model from the structural description of the social network underlying the simulation. This simple and elegant design principle gives GeSoMo generalizing power: Arbitrary existing and future SNMs can be used without changing GeSoMo itself. Our evaluation results show that GeSoMo produces simulations that are coherent with a broad range of empirical data describing real-world human social behavior and mobility.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-65&engl=0}
}
@inproceedings {INPROC-2010-63,
   author = {Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
   title = {{StreamShaper: Coordination Algorithms for Participatory Mobile Urban Sensing}},
   booktitle = {Proceedings of the 7th IEEE International Conference on Mobile Ad-hoc and Sensor Systems (MASS'10)},
   address = {San Francisco, CA, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-63/INPROC-2010-63.pdf,     http://www.comnsense.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we introduce mechanisms for automated mapping of urban areas that provide a virtual sensor abstraction to the applications. We envision a participatory system that exploits widely available devices as mobile phones to cooperatively read environmental conditions as air quality or noise pollution, and map these measurements to stationary virtual sensors. We propose spatial and temporal coverage metrics for measuring the quality of acquired sensor data that reflect the conditions of urban areas and the uncontrolled movement of nodes. To achieve quality requirements and efficiency in terms of energy consumption, this paper presents two algorithms for coordinating sensing. The first is based on a central control instance, which assigns sensing tasks to mobile nodes based on movement predictions. The second algorithm is based on coordination of mobile nodes in an ad-hoc network. By extensive simulations, we show that these algorithms achieve a high quality of readings, which is about 95\% of the maximum possible. Moreover, the algorithms achieve a very high energy efficiency allowing for drastic savings compared to uncoordinated sensing.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-63&engl=0}
}
@inproceedings {INPROC-2010-60,
   author = {Faraz Memon and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Index Recommendation Tool for Optimized Information Discovery Over Distributed Hash Tables}},
   booktitle = {Proceedings of the 35th International Conference on Local Computer Networks (LCN '10)},
   address = {Dever, CO, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     E.1 Data Structures,     E.2 Data Storage Representations,     H.3.1 Content Analysis and Indexing},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-60/INPROC-2010-60.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Peer-to-peer (P2P) networks allow for efficient information discovery in large-scale distributed systems. Although point queries are well supported by current P2P systems -- in particular systems based on distributed hash tables (DHTs) --, providing efficient support for more complex queries remains a challenge. Our research focuses on the efficient support for multi-attribute range (MAR) queries over DHT-based information discovery systems. Traditionally, the support for MAR queries over DHTs has been provided either by creating an individual index for each data attribute or by creating a single index using the combination of all data attributes. In contrast to these approaches, we propose to create a set of indices over selected attribute combinations. In order to limit the overhead induced by index maintenance, the total number of created indices has to be limited. Thus, the resulting problem is to create a limited number of indices such that the overall system performance is optimal for MAR queries. In this paper, we propose an index recommendation tool that implements heuristic solutions to this NP-hard problem. Our evaluations show that these heuristics lead to a close-to-optimal system performance for MAR queries.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-60&engl=0}
}
@inproceedings {INPROC-2010-57,
   author = {Stamatia Rizou and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Providing QoS Guarantees for Large-Scale Operator Networks}},
   booktitle = {Proceedings of the 12th IEEE International Conference on High Performance Computing and Communications},
   address = {Melbourne, VIC, Australia},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {337--345},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2010},
   doi = {10.1109/HPCC.2010.53},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-57/INPROC-2010-57.pdf,     http://dx.doi.org/10.1109/HPCC.2010.53},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Application areas like global sensor networks and data stream processing involve the on-line processing of large amounts of data in an overlay network of operators on top of the Internet infrastructure. Trying to fulfill QoS guarantees in such networks is a challenging task that should be realized under the requirement for optimal usage of common resources in the network. Therefore in this paper, we formalize a constrained optimization problem for the placement of operators in an overlay network which strives for satisfying user QoS constraints subject to latency, while minimizing the network load induced by the deployment of the operators in the network. Since the initial problem is NP-hard, we solve at a first step the problem in an intermediate continuous latency space and then we map the continuous solution to its discrete variant. Our evaluations provide an analysis about the inherent interdepedence between the two metrics, network usage and latency, subject to this paper and furthermore shows that our algorithm achieves a good balance between the user requirements and the usage of the network resources.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-57&engl=0}
}
@inproceedings {INPROC-2010-56,
   author = {Stamatia Rizou and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Solving the Multi-operator Placement Problem in Large-Scale Operator Networks}},
   booktitle = {Proceedings of the 19th International Conference on Computer Communication Networks},
   address = {Zurich, Switzerland},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2010},
   doi = {10.1109/ICCCN.2010.5560127},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-56/INPROC-2010-56.pdf,     http://dx.doi.org/10.1109/ICCCN.2010.5560127},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Processing streams of data in an overlay network of operators distributed over a wide-area network is a common idea shared by different applications such as distributed event correlation systems and large-scale sensor networks. In order to utilize network resources efficiently and allow for the parallel deployment of a large number of large-scale operator networks, suitable placement algorithms are vital that place operators on physical nodes. In this paper, we present a distributed placement algorithm that minimizes the bandwidth-delay product of data streams between operators of the network in order to reduce the induced network load. Since the fundamental optimization problem is NP-hard, we propose a heuristic solution. First, we calculate an optimal solution in an intermediate continuous search space, called latency space. Subsequently the continuous solution is mapped to the physical network. Our evaluations show that this algorithm reduces the resulting network load significantly compared to state of the art algorithms and achieves results close to the optimum.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-56&engl=0}
}
@inproceedings {INPROC-2010-46,
   author = {Stefan F{\"o}ll and Klaus Herrmann and Christian Hiesinger},
   title = {{Flow-Based Context Prediction}},
   booktitle = {Proceedings of the 7th International Conference on Pervasive Services (ICPS 2010), Berlin, Germany, July 13-15, 2010},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--1},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2010},
   keywords = {Context prediction, Markov model, workflows, context awareness, probabilistic user behaviour},
   language = {Englisch},
   cr-category = {G.3 Probability and Statistics,     I.2.6 Artificial Intelligence Learning},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-46/INPROC-2010-46.pdf},
   contact = {stefan.foell@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Context prediction has been recognized as an enabler for proactive pervasive services that anticipate future situations already ahead of time. Traditional context predictors are limited by their agnostic view on the targeted application domain when analysing context histories of past user behaviour. Awareness about the processes in which an entity is involved can provide rich information to foresee future context changes more accurately. We present an approach for context prediction in pervasive environments that are characterized by context-aware workflows. In order to benefit from the explicit knowledge about human behaviour in these environments, we devise a context predictor that learns the relationship of context changes with the flow of activities performed by humans. This relationship is encoded as a probabilistic state transition system that can be explored to determine the most likely paths of future context occurrences. Our evaluation shows that our enhanced predictor is able to extract patterns from context histories that are inaccessible to history-only predictors and significantly improves the prediction accuracy.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-46&engl=0}
}
@inproceedings {INPROC-2010-43,
   author = {Stamatia Rizou and Kai H{\"a}ussermann and Frank D{\"u}rr and Nazario Cipriani and Kurt Rothermel},
   title = {{A system for distributed context reasoning.}},
   booktitle = {Proceedings of ICAS’10: International Conference on Autonomous and Autonomic Systems},
   publisher = {IEEE Computer Society Conference Publishing Services},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {84--89},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2010},
   isbn = {978-0-7695-3970-6},
   doi = {10.1109/ICAS.2010.21},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-43/INPROC-2010-43.pdf,     http://dx.doi.org/10.1109/ICAS.2010.21},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {Context aware systems use context information to adapt their behaviour accordingly. In order to derive high level context information from low level context, such as sensor values, context reasoning methods that correlate observable context information, are necessary. Several context reasoning mechanisms have been proposed in the literature. Usually these mechanisms are centralized, leading to suboptimal utilization of network resources and poor system performance in case of large-scale scenarios. Therefore to increase the scalability of context reasoning systems the development of methods that distribute the reasoning process is necessary. Existing distributed approaches are method specific and do not provide a generic formalization for distributed reasoning. In this paper we introduce a novel system which enables distributed context reasoning in a generic way that is independent of the reasoning algorithm.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-43&engl=0}
}
@inproceedings {INPROC-2010-38,
   author = {Gerald G. Koch and M. Adnan Tariq and Boris Koldehofe and Kurt Rothermel},
   title = {{Event processing for large-scale distributed games}},
   booktitle = {Proceedings of the 4th International Conference on Distributed Event-Based Systems (DEBS'10)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {103--104},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2010},
   doi = {http://doi.acm.org/10.1145/1827418.1827440},
   isbn = {978-1-60558-927-5},
   keywords = {Cordies; SpoVNet; CEP},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-38/INPROC-2010-38.pdf,     http://doi.acm.org/10.1145/1827418.1827440},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Novel peer-to-peer-based multiplayer online games are instantiated in an ad-hoc manner without the support of dedicated infrastructure and maintain their state in a distributed manner. Although their employed communication paradigms provide efficient access to sections of distributed state, such communication fails if the participants need to access large subsets of the application state in order to detect high-level situations. We propose a demonstration that shows how multiplayer online games can benefit from using publish/subscribe communication and complex event processing alongside their traditional communication paradigm.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-38&engl=0}
}
@inproceedings {INPROC-2010-32,
   author = {Lars Geiger and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Aggregation of User Contexts in Context-based Communication}},
   booktitle = {Proceedings of the 6th Euro-NF Conference on Next Generation Internet (NGI 2010)},
   address = {Paris},
   publisher = {IEEE Xplore},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.2.4 Distributed Systems,     C.2.6 Internetworking},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-32/INPROC-2010-32.pdf,     http://dx.doi.org/10.1109/NGI.2010.5534466},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {A context-based communication system enables the indirect addressing and routing of messages according to the users' contexts. This provides, for example, the means to send a message to all students on campus who attend a certain class, with information about an upcoming exam. However, for a targeted forwarding of messages towards users, the routers need information about the context of connected users. Global knowledge, i.e., each router knowing about every user, is not scalable, though, because of the necessary update messages to keep this information up-to-date. To address this challenge, a router can aggregate similar contexts and only provide such an aggregated view to neighboring routers. In this paper, we present an approach to aggregate similar contexts, based on a similarity measure for user contexts. The algorithm can be adjusted according to the observed messages and user contexts in the system by specifying a similarity threshold to determine when contexts are aggregated. The aggregation of user contexts improves the scalability of our approach by significantly reducing the load of context updates by up to 30\%, depending on the usage of the system. This improvement comes at the cost of a negligible increase in false positive messages due to the loss of information used for forwarding messages.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-32&engl=0}
}
@inproceedings {INPROC-2010-31,
   author = {Muhammad Adnan Tariq and Gerald Georg Koch and Boris Koldehofe and Imran Khan and Kurt Rothermel},
   title = {{Dynamic publish/subscribe to meet subscriber-defined delay and bandwidth constraints}},
   booktitle = {The Sixteenth International Conference on Parallel Computing (Euro-Par 2010)},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {458--470},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2010},
   keywords = {Content-based; P2P; Event-based; Bandwidth; End-to-end Delay; Spatial indexing; QoS},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-31/INPROC-2010-31.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Current distributed publish/subscribe systems assume that all participants have similar QoS requirements and equally contribute to the system’s resources. However, in many real-world applications, the message delay tolerance of individual peers may differ widely. Disseminating messages according to individual delay requirements not only allows for the satisfaction of user-specific needs but also significantly improves the utilization of the resources in a publish/subscribe system. In this paper, we propose a peer-to-peer-based approach to satisfy the individual delay requirements of subscribers in the presence of bandwidth constraints. Our approach allows subscribers to dynamically adjust the granularity of their subscriptions according to their bandwidth constraints and delay requirements. Subscribers maintain the publish/subscribe overlay in a decentralized manner by establishing connections to peers that provide messages meeting exactly their subscription granularity and complying to their delay requirements. Evaluations show that for practical workloads, the proposed system scales up to a large number of subscribers and performs robustly in a very dynamic setting.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-31&engl=0}
}
@inproceedings {INPROC-2010-30,
   author = {Andreas Grau and Klaus Herrmann and Kurt Rothermel},
   title = {{NETplace: Efficient Runtime Minimization of Network Emulation Experiments}},
   booktitle = {Proceeding of the International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS'10) [Best Paper Award]},
   address = {Ottawa, Canada},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {265--272},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-30/INPROC-2010-30.pdf,     http://www.ipvs.uni-stuttgart.de/abteilungen/vs/abteilung/mitarbeiter/andreas.grau_infos/spects10bestpaper.jpg,     http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5589304},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Network emulation is an efficient method for evaluating distributed applications and communication protocols by combining the benefits of real world experiments and network simulation. The process of network emulation involves execution of thousands of connected virtual nodes running the software under test in a controlled environment. Along with the quality of the experiment results, the runtime of network experiments strongly influences the convenience of users and operators of emulation testbeds. The goal of this paper is, therefore, to minimize the experiment runtime of network emulations. In order to achieve this goal, we make the following contributions in this paper: First, we present a highly scalable emulation architecture to efficiently support network emulation testbeds with multicore CPUs. Second, we propose a detailed and generic cost model for the communication costs of emulation testbeds. Third, we present an efficient placement strategy (NETplace) to assign virtual nodes to physical nodes of the testbed while minimizing the runtime of network experiments. Therefore, we combine graph partitioning and greedy approaches. Our evaluations show that our placement strategy outperforms existing methods by reducing the experiment runtime up to 64\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-30&engl=0}
}
@inproceedings {INPROC-2010-24,
   author = {Muhammad Adnan Tariq and Boris Koldehofe and Ala Altaweel and Kurt Rothermel},
   title = {{Providing basic security mechanisms in broker-less publish/subscribe systems}},
   booktitle = {Proceedings of the 4th International Conference on Distributed Event-Based Systems (DEBS'10), 2010},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {38--49},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2010},
   keywords = {Content-based; P2P; Broker-less; Security; Identity-based encryption; IBE; Attribute-based encryption; Clustering},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-24/INPROC-2010-24.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The provisioning of basic security mechanisms such as authentication and confidentiality is highly challenging in a content-based publish/subscribe system. Authentication of publishers and subscribers is difficult to achieve due to the loose coupling of publishers and subscribers. Similarly, confidentiality of events and subscriptions conflicts with contentbased routing. In particular, content-based approaches in broker-less environments do not address confidentiality at all. This paper presents a novel approach to provide confidentiality and authentication in a broker-less content-based publish-subscribe system. By adapting the pairing-based cryptography mechanisms to the needs of publish/subscribe authentication of publisher and subscriber as well as confidentiality of events is ensured. Furthermore, an algorithm to cluster subscribers according to their subscriptions preserves a weak notion of subscription confidentiality. Our approach provides fine grained key management and the cost for encryption, decryption and routing is in the order of subscribed attributes. Moreover, the simulation results verify that supporting security is affordable with respect to the cost for overlay construction and event dissemination latencies, thus preserving scalability of the system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-24&engl=0}
}
@inproceedings {INPROC-2010-22,
   author = {Bj{\"o}rn Schilling and Boris Koldehofe and Udo Pletat and Kurt Rothermel},
   title = {{Distributed Heterogeneous Event Processing: Enhancing Scalability and Interoperability of CEP in an Industrial Context}},
   booktitle = {Proceedings of the 4th ACM International Conference on Distributed Event-Based Systems (DEBS); Cambridge, United Kingdom, July 12-15, 2010},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {150--159},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2010},
   isbn = {1827418.1827453},
   language = {Deutsch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-22/INPROC-2010-22.pdf,     http://portal.acm.org/citation.cfm?doid=1827418.1827453},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Although a significant amount of research has investigated the benefits of distributed CEP in terms of scalability and extensibility, there is an ongoing reluctance in deploying distributed CEP in an industrial context. In this paper we present the DHEP system developed together with the IBM laboratory in B{\"o}blingen. It addresses some of the key problems in increasing the acceptance of distributed CEP, for example supporting interoperability between heterogeneous event processing systems. We present the concepts behind the DHEP system and show how those concepts help to achieve scalable and extensible event processing in an industrial context. Moreover, we verify in an evaluation study that the additional cost imposed by the DHEP system is moderate and 'affordable' for the benefits provided.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-22&engl=0}
}
@inproceedings {INPROC-2010-21,
   author = {Gerald Georg Koch and Boris Koldehofe and Kurt Rothermel},
   title = {{Cordies: Expressive event correlation in distributed systems}},
   booktitle = {Proceedings of the 4th International Conference on Distributed Event-Based Systems (DEBS'10)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {26--37},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2010},
   isbn = {978-1-60558-927-5},
   doi = {10.1145/1827418.1827424},
   keywords = {Cordies; distributed complex event processing; restriction graph; correlation description},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-21/INPROC-2010-21.pdf,     http://doi.acm.org/10.1145/1827418.1827424},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Complex Event Processing (CEP) is the method of choice for the observation of system states and situations by means of events. A number of systems have been introduced that provide CEP in selected environments. Some are restricted to centralised systems, or to system with synchronous communication, or to a limited space of event relations that are defined in advance. Many modern systems, though, are inherently distributed and asynchronous, and require a more powerful CEP. We present Cordies, a distributed system for the detection of correlated events that is designed for the operation in large-scale, heterogeneous networks and adapts dynamically to changing network conditions. With its expressive language to describe event relations, it is suitable for environments where neither the event space nor the situations of interest are predefined but are constantly adapted.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-21&engl=0}
}
@inproceedings {INPROC-2010-18,
   author = {Andreas Benzing and Boris Koldehofe and Kurt Rothermel},
   title = {{Distributed Diagnostic Simulations for the Smart Grid}},
   booktitle = {Accepted Poster at the 1st International Conference on Energy-Efficient Computing and Networking: E-Energy 2010},
   publisher = {Online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--3},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2010},
   keywords = {Diagnostic Simulation; Global Sensor Grid},
   language = {Deutsch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-18/INPROC-2010-18.pdf},
   contact = {andreas.benzing@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Energy efficiency is usually achieved by reducing the energy consumption as far as possible. With the growing amount of renewable energy sources, energy efficient usage also has to consider what kind of and when power is consumed. By matching the availability of electrical power with the current demands, the amount of unused energy and therefore overall energy production can be reduced. The so called smart grid aims to provide this matching with a broad deployment of smart meters to acquire the current demand. However, current approaches to the smart grid cannot handle the huge amount of sensors and energy sources involved in a scalable way. Most data acquisition systems focus on the lookup and reading of single sensors and therefore do not fit the requirements of a large scale power grid simulation. We propose a Global Sensor Grid (GSG) which provides consumers with data preprocessed to their needs instead of delivering raw sensor data. With this decoupling from the actual sensors, multiple consumers can benefit from improvements in data acquisition and avoidance of the redundant processing of data by each consumer. By integrating so-called diagnostic simulations into the GSG, gaps in sensor coverage can be filled with higher precision than normal interpolation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-18&engl=0}
}
@inproceedings {INPROC-2010-17,
   author = {Frank D{\"u}rr and Harald Weinschrott and Kurt Rothermel},
   title = {{Geocast Routing of Symbolically Addressed Messages in Wireless Mesh Networks}},
   booktitle = {Proceedings of the 8th IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops '10)},
   address = {Mannheim, Germany},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {552--557},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-17/INPROC-2010-17.pdf,     http://dx.doi.org/10.1109/PERCOMW.2010.5470499},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Geocast protocols can be used to send messages to all receivers in a geographic target area. In this paper we present geocast routing algorithms for Wireless Mesh Networks that are tailored to symbolic addressing using symbolic location names like floor or room numbers. Since in particular indoors no geometric information is available, our algorithms use symbolic location models to derive directional information for routing. Moreover, we show how to integrate geometric and symbolic geographic routing algorithms into a hybrid routing approach which is applicable to larger areas consisting of symbolically and geometrically defined locations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-17&engl=0}
}
@inproceedings {INPROC-2010-16,
   author = {Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Symbolic Routing for Location-based Services in Wireless Mesh Networks}},
   booktitle = {Proceedings of the IEEE 24nd International Conference on Advanced Information Networking and Applications},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-16/INPROC-2010-16.pdf,     http://dx.doi.org/10.1109/AINA.2010.71},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Wireless Mesh Networks are cost-efficient medium-scale networks that have the potential to serve as an infrastructure for advanced location-based services. As a basis for these services we present a routing algorithm that allows to address intuitive symbolic coordinates. This algorithm is based on a proactively maintained geographic routing structure that mimics the structure of a symbolic location model. Message forwarding is done greedily along short paths defined by a symbolic location model and if this fails, through an hierarchical overlay network built by selected mesh routers. We show how a geocast communication mechanism that allows to send messages to all hosts within a specific location can be implemented with this routing algorithm. In extensive evaluations we show that a low proactive routing overhead allows to achieve high message delivery rates even in case of mobility. Moreover, we show that the paths achieved are only 25\% longer than the theoretic optimal paths for a wide range of simulation settings.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-16&engl=0}
}
@inproceedings {INPROC-2010-15,
   author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Efficient Tracking of Moving Objects using Generic Remote Trajectory Simplification (Demo Paper)}},
   booktitle = {Proceedings of the 8th IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops '10). Mannheim, Germany. March 2010},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {829--831},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2010},
   keywords = {Remote trajectory simplification; tracking; dead reckoning; moving objects database; MOD; line simplification},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-15/INPROC-2010-15.pdf,     http://dx.doi.org/10.1109/PERCOMW.2010.5470553},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Position information of moving objects plays a vital role in many pervasive applications. Therefore, moving objects databases (MODs), which can manage trajectory data of a number objects, are used in many pervasive systems. A crucial problem with MODs is how to efficiently track a remote object's trajectory in real-time, i.e. how to continuously report the sensed trajectory data to the MOD with minimal effort. For this purpose, we present a prototypical implementation of the Generic Remote Trajectory Simplification (GRTS) protocol, which optimizes storage consumption, processing, and communication costs. Our prototypical system includes a fully functional MOD as well as map-based mobile applications for subnotebooks and smartphones to illustrate the functioning of GRTS.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-15&engl=0}
}
@inproceedings {INPROC-2010-118,
   author = {Frank D{\"u}rr and Marius Wernke and Pavel Skvortsov and Kurt Rothermel},
   title = {{Towards a Position Sharing Approach for Location-based Services}},
   booktitle = {Proceedings of the W3C Workshop on Privacy for Advanced Web APIs},
   publisher = {Online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--3},
   type = {Workshop-Beitrag},
   month = {Juli},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-118/INPROC-2010-118.pdf,     http://www.w3.org/2010/api-privacy-ws/papers/privacy-ws-16.pdf,     http://www.priloc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In partially-trusted system environments like the WWW, the management of private user positions is a great challenge. On the one hand, location-based services of different partially-trusted providers have to be provided with position information. On the other hand, location servers, which are responsible for the management of user positions, might as well be operated by only partially-trusted providers. Therefore, in order to protect his privacy, a user might only want to store position information of limited precision on location servers, and also provide location-based services with position information of limited precision. In this position paper, we sketch a novel position sharing approach that enables the user to tightly control the precision of position information stored on servers and provided to location-based services. This approach is based on the idea of distributing position information among a set of servers of different providers such that a compromised server only reveals information of strictly limited precision.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-118&engl=0}
}
@inproceedings {INPROC-2010-116,
   author = {Faraz Memon and Daniel Tiebler and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Optimized Information Discovery using Self-adapting Indices over Distributed Hash Tables}},
   booktitle = {Proceedings of 29th International Performance Computing and Communications Conference (IPCCC'10)},
   address = {Albuquerque, New Mexico, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--9},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2010},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     E.1 Data Structures,     E.2 Data Storage Representations,     H.3.1 Content Analysis and Indexing},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-116/INPROC-2010-116.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Distributed Hash Table (DHT)-based peer-to-peer information discovery systems have emerged as highly scalable systems for information storage and discovery in massively distributed networks. Originally DHTs supported only point queries. However, recently they have been extended to support more complex queries, such as multi-attribute range (MAR) queries. Generally, the support for MAR queries over DHTs has been provided either by creating an individual index for each data attribute or by creating a single index using the combination of all data attributes. In contrast to these approaches, we propose to create and modify indices using the attribute combinations that dynamically appear in MAR queries in the system. In this paper, we present an adaptive information discovery system that adapts the set of indices according to the dynamic set of MAR queries in the system. The main contribution of this paper is a four-phase scalable index adaptation process. Our evaluations show that the adaptive information discovery system continuously optimizes the overall system performance for MAR queries. Moreover, compared to a non-adaptive system, the adaptive information discovery system shows several orders of magnitude improved performance.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-116&engl=0}
}
@inproceedings {INPROC-2010-06,
   author = {Stephan Schuhmann and Klaus Herrmann and Kurt Rothermel},
   title = {{Efficient Resource-Aware Hybrid Configuration of Distributed Pervasive Applications}},
   booktitle = {Proceedings of the 8th International Conference on Pervasive Computing (Pervasive 2010); Helsinki, Finland, May 17-20, 2010},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {6030},
   pages = {373--390},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2010},
   keywords = {Adaptivity; Components; Distributed Application Configuration; Heterogeneous Environments; Middleware; Pervasive Applications},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2010-06/INPROC-2010-06.pdf,     http://www.springerlink.com/content/x6607vl0w9753683/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {As the size and complexity of Pervasive Computing environments increases, configuration and adaptation of distributed applications gains importance. These tasks require automated system support, since users must not be distracted by the (re-)composition of applications. In homogeneous ad hoc scenarios, relying on decentralized configuration schemes is obviously mandatory, while centralized approaches may help to reduce latencies in weakly heterogeneous infrastructure-based environments. However, in case of strongly heterogeneous pervasive environments including several resource-rich and resource-weak devices, both approaches may lead to suboptimal results concerning configuration latencies: While the resource-weak devices represent bottlenecks for decentralized configuration, the centralized approach faces the problem of not utilizing parallelism. Instead, a hybrid approach that involves only the subset of resource-rich devices is capable of rendering configuration and adaptation processes more efficiently. In this paper, we present such a resource-aware hybrid scheme that effectively reduces the time required for configuration processes. This is accomplished by a balanced-load clustering scheme that exploits the computational power of resource-rich devices, while avoiding bottlenecks in (re-)configurations. We present real-world evaluations which confirm that our approach reduces configuration latencies in heterogeneous environments by more than 30 \% compared to totally centralized and totally decentralized approaches. This is an important step towards seamless application configuration.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-06&engl=0}
}
@inproceedings {INPROC-2009-86,
   author = {Matthias Grossmann and Nicola H{\"o}nle and Carlos L{\"u}bbe and Harald Weinschrott},
   title = {{An Abstract Processing Model for the Quality of Context Data}},
   booktitle = {Proceedings of the 1st International Workshop on Quality of Context},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {132--143},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2009},
   keywords = {uncertainty; inconsistency; trust; processing model},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-86/INPROC-2009-86.pdf,     http://dx.doi.org/10.1007/978-3-642-04559-2_12},
   contact = {Matthias.Grossmann@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {Data quality can be relevant to many applications. Especially applications coping with sensor data cannot take a single sensor value for granted. Because of technical and physical restrictions each sensor reading is associated with an uncertainty. To improve quality, an application can combine data values from different sensors or, more generally, data providers. But as different data providers may have diverse opinions about a certain real world phenomenon, another issue arises: inconsistency. When handling data from different data providers, the application needs to consider their trustworthiness. This naturally introduces a third aspect of quality: trust. In this paper we propose a novel processing model integrating the three aspects of quality: uncertainty, inconsistency and trust.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-86&engl=0}
}
@inproceedings {INPROC-2009-79,
   author = {Hannes Wolf and Klaus Herrmann and Kurt Rothermel},
   title = {{Modeling Dynamic Context Awareness for Situated Workflows}},
   booktitle = {OTM 2009 Workshops},
   editor = {R Meersman and P Herrero and T Dillon},
   address = {Berlin, Heidelberg},
   publisher = {Springer Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {5872},
   pages = {98--107},
   type = {Workshop-Beitrag},
   month = {November},
   year = {2009},
   language = {Deutsch},
   cr-category = {H.4.1 Office Automation,     H.3.3 Information Search and Retrieval},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-79/INPROC-2009-79.pdf,     http://www.springerlink.com/content/r6783472331327u4},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {A major challenge for pervasive computing is to support continuous adaptation of applications to the behavior of the user. Recent research has adopted classical workflows as alternative programming paradigm for pervasive applications and approaches for context aware workflow models have been presented. However the current approaches suffer from the low flexibility of classical workflow models. We present a solution that allows attaching workflows to real-world objects and defining relevant context dynamically in relation to those objects. The benefits are a dynamic, yet simple modeling of context constraints and events in pervasive workflows and a greatly reduced amount of context information that must be provided to the workflow.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-79&engl=0}
}
@inproceedings {INPROC-2009-71,
   author = {Davide Frey and Rachid Guerraoui and Anne-Marie Kermarrec and Boris Koldehofe and Martin Mogensen and Maxime Monod and Vivien Qu{\'e}ma},
   title = {{Heterogeneous Gossip}},
   booktitle = {Proceedings of the 10th ACM/IFIP/USENIX International Conference on Middleware},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {42--61},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2009},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {http://delivery.acm.org/10.1145/1660000/1656984/a3-frey.pdf?key1=1656984&key2=2295269621&coll=GUIDE&dl=ACM&CFID=83635975&CFTOKEN=34871073},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Gossip-based information dissemination protocols are considered easy to deploy, scalable and resilient to network dynamics. Load-balancing is inherent in these protocols as the dissemination work is evenly spread among all nodes. Yet, large-scale distributed systems are usually heterogeneous with respect to network capabilities such as bandwidth. In practice, a blind load-balancing strategy might significantly hamper the performance of the gossip dissemination. This paper presents HEAP, HEterogeneity-Aware gossip Protocol, where nodes dynamically adapt their contribution to the gossip dissemination according to their bandwidth capabilities. Using a continuous, itself gossip-based, approximation of relative bandwidth capabilities, HEAP dynamically leverages the most capable nodes by increasing their fanout, while decreasing by the same proportion that of less capable nodes. HEAP preserves the simple and proactive (churn adaptation) nature of gossip, while significantly improving its effectiveness. We extensively evaluate HEAP in the context of a video streaming application on a testbed of 270 PlanetLab nodes. Our results show that HEAP significantly improves the quality of the streaming over standard homogeneous gossip protocols, especially when the stream rate is close to the average available bandwidth.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-71&engl=0}
}
@inproceedings {INPROC-2009-66,
   author = {Lars Geiger and Ronald Schertle and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Temporal Addressing for Mobile Context-Aware Communication}},
   booktitle = {Proceedings of the Sixth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous '09), Toronto, ON, Canada, July 13-16, 2009},
   publisher = {ICST},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2009},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.2.4 Distributed Systems,     C.2.6 Internetworking},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-66/INPROC-2009-66.pdf,     http://www.ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5326393},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobile clients in context-aware systems benefit from the indirect addressing of users via their context (contextcast), such as addressing messages to all users in downtown Toronto whose age is below 35. There is, however, almost no support for a temporal decoupling in such a contextcast system, i.e., the addressing of users that were or will be in a certain context in the past or future, respectively. This could for instance be used to distribute the minutes of a meeting to all people who attended the meeting in room 1.138, 3 days ago, between 1 and 3 pm. To enable a context-aware communication system to address messages with temporal relations, especially those contexts in the past, the system needs to manage information about user context histories. This poses the risk that the system can be abused to profile users, which would most probably hinder acceptance. Therefore, privacy aspects need to be considered in the core design of such a system. We present an extension to our earlier work, which allows a temporal decoupling of messages and users and requires very little additional overhead to manage historic context information. The solution includes mechanisms to efficiently disseminate messages to both users with past and future contexts, while effectively preventing user profiling through the use of virtual identities.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-66&engl=0}
}
@inproceedings {INPROC-2009-51,
   author = {Ralph Lange and Harald Weinschrott and Lars Geiger and Andre Blessing and Frank D{\"u}rr and Kurt Rothermel and Hinrich Sch{\"u}tze},
   title = {{On a Generic Uncertainty Model for Position Information}},
   booktitle = {Proceedings of the 1st International Workshop on Quality of Context},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--12},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2009},
   keywords = {data uncertainty; position information; position accuracy; spatial queries},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-51/INPROC-2009-51.pdf,     http://www.springerlink.com/content/85450711831008k0/},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Maschinelle Sprachverarbeitung;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Position information of moving as well as stationary objects is generally subject to uncertainties due to inherent measuring errors of positioning technologies, explicit tolerances of position update protocols, and approximations by interpolation algorithms. There exist a variety of approaches for specifying these uncertainties by mathematical uncertainty models such as tolerance regions or the Dilution of Precision (DOP) values of GPS. In this paper we propose a principled generic uncertainty model that integrates the different approaches and derive a comprehensive query interface for processing spatial queries on uncertain position information of different sources based on this model. Finally, we show how to implement our approach with prevalent existing uncertainty models.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-51&engl=0}
}
@inproceedings {INPROC-2009-48,
   author = {Hanna Eberle and Stefan F{\"o}ll and Klaus Herrmann and Frank Leymann and Annapaola Marconi and Tobias Unger and Hannes Wolf},
   title = {{Enforcement from the Inside: Improving Quality of Business in Process Management}},
   booktitle = {2009 IEEE International Conference on Web Services (ICWS 2009)},
   address = {Los Alamitos, CA, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {405--412},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2009},
   doi = {10.1109/ICWS.2009.82},
   isbn = {978-0-7695-3709-2},
   keywords = {Business Process Management; BPM; BPEL; Enforcement},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-48/INPROC-2009-48.pdf,     http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=5175850,     http://www2.computer.org/portal/web/csdl/doi/10.1109/ICWS.2009.82},
   contact = {unger@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we introduce a new modeling tool for constraint handling in the area of workflow technology. The constraint handlers can be used to improve the quality of business processes but without changing already existing business logic. Todays workflow languages provide no possibility to model constraints and the actions in case the constraints get violated explicitly. Fault and event handling mechanisms to react to events not expected in normal executions are only provided by the BPEL language. Using BPEL as workflow language we integrate the constraint handling extension without changing any existing semantics in a smart way. In our approach we use this fault and event handling mechanisms to extend the BPEL language with a constraint handling mechanism. By integrating this constraint handling tool into the BPEL language we provide an approach for quality driven process modeling with the BPEL language.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-48&engl=0}
}
@inproceedings {INPROC-2009-44,
   author = {Andreas Grau and Klaus Herrmann and Kurt Rothermel},
   title = {{Efficient and Scalable Network Emulation using Adaptive Virtual Time}},
   booktitle = {Proceedings of the 18th International Conference on Computer Communications and Networks (ICCCN 2009)},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2009},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-44/INPROC-2009-44.pdf,     http://dx.doi.org/10.1109/ICCCN.2009.5235306},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Performance analysis and functionality testing are major parts of developing distributed software systems. Since the number of communicating software instances heavily influences the behavior of distributed applications and communication protocols, evaluation scenarios have to consider a large number of nodes. Network emulation provides an infrastructure for running these experiments using real prototype implementations in a controllable and realistic environment. Large-scale experiments, however, have a high resource consumption which often exceeds available physical testbed resources. Time dilation allows for reducing the resource demands of a scenario at the expense of the experiment's runtime. However, current approaches only consider a constant time dilation factor, which wastes a lot of resources in case of scenarios with varying load. We propose a framework for adaptive time virtualization that significantly reduces the runtime of experiments by improving resource utilization in network emulation testbeds. In this framework, resource demands are monitored and the time dilation factor is dynamically adapted to the required level. Our evaluation shows that adaptive virtual time in combination with our lightweight node virtualization architecture allows us to increase the possible scenario sizes by more than an order of magnitude and, at the same time, ensure unbiased emulation results. This represents an important contribution to making network emulation systems highly scalable.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-44&engl=0}
}
@inproceedings {INPROC-2009-42,
   author = {Faraz Memon and Daniel Tiebler and Frank D{\"u}rr and Kurt Rothermel and Marco Tomsu and Peter Domschitz},
   title = {{Scalable Spatial Information Discovery over Distributed Hash Tables}},
   booktitle = {Procs. of 4th International Conference on COMmunication System softWAre and middlewaRE (COMSWARE'09), Dublin, Ireland, June 2009. ACM.},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2009},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     H.3.3 Information Search and Retrieval},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-42/INPROC-2009-42.pdf,     http://doi.acm.org/10.1145/1621890.1621892},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we present a Peer-to-Peer (P2P) spatial information discovery system that enables spatial range queries over Distributed Hash Tables (DHTs). Our system utilizes a less-distorting octahedral map projection in contrast to the quadrilateral projections used by majority of the previously proposed systems, to represent the spatial information. We also introduce a Space-Filling Curve (SFC)-based data placement strategy that reduces the probability of data hot-spots in the network. Moreover, we show that our system achieves scalable resolution of location-based range queries by utilizing a tree-based query optimization algorithm. Compared to the basic query resolution algorithm, the query optimization algorithm reduces the average number of parallel messages used to resolve a query, by a factor of 96\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-42&engl=0}
}
@inproceedings {INPROC-2009-36,
   author = {S{\'e}rgio Alves and Boris Koldehofe and Hugo Miranda and Francois Taiani},
   title = {{Design of a Backup Network for Catastrophe Scenarios}},
   booktitle = {Proceedings of the ACM International Workshop on Advanced Topics in Mobile Computing for Emergency Management: Communication and Computing Platforms (MCEM)},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {613--617},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2009},
   doi = {10.1145/1582379.1582512},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Communication networks play a fundamental role in the response to a massive catastrophe, like an earthquake or a large-scale terrorist attack to a major urban area. In such situations, command centres must be able to rely on a fully operational communication network, for example to learn about on-going situations and allocate and guide the rescue teams. Communication is bidirectional: once in the field, these teams will feed the command centre with a more accurate view of the situation, contributing to the efficient allocation of the resources. Failures in this network, even if localised to some of the regions affected by the catastrophe, can have costs both monetary and in human lives. In this position paper, we propose the creation of a redundant, best-effort, emergency communication network that could serve to mitigate localised failures using off-the-shelf widespread technology. We give an overview of an architecture for a backup network, highlight the possible advantage of such an architecture to disaster management and discuss challenges that need to be overcome in realizing it.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-36&engl=0}
}
@inproceedings {INPROC-2009-32,
   author = {Lars Geiger and Frank D{\"u}rr and Kurt Rothermel},
   title = {{On Contextcast: A Context-aware Communication Mechanism}},
   booktitle = {IEEE International Conference on Communications, 2009. ICC '09.},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2009},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.2.4 Distributed Systems,     C.2.6 Internetworking},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-32/INPROC-2009-32.pdf,     http://dx.doi.org/10.1109/ICC.2009.5199239},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The dissemination of messages according to clients' contexts (i.e., location and other attributes) opens up new possibilities in context-aware systems. While geocast or content-based publish/subscribe forward messages according to client location or attributes, respectively, neither uses a combination of the two. In this paper, we present this new communication paradigm and the challenges it poses. We also extend concepts from publish/subscribe networks to efficiently deal with highly dynamic user location to lower update rates by approximating the user's location. This reduces update rates by between 25\% and 90\%, depending on the granularity of the approximation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-32&engl=0}
}
@inproceedings {INPROC-2009-24,
   author = {Harald Weinschrott and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Efficient Capturing of Environmental Data with Mobile RFID Readers}},
   booktitle = {Proceedings of the 10th International Conference on Mobile Data Management (MDM'09); Taipei, Taiwan, Mai 18-20, 2009},
   address = {Taipei, Taiwan},
   publisher = {IEEE Computer Society Conference Publishing Services},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2009},
   keywords = {ad-hoc; mobile; RFID-sensor; urban sensing},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-24/INPROC-2009-24.pdf,     http://doi.ieeecomputersociety.org/10.1109/MDM.2009.15,     http://www.comnsense.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we introduce a novel scenario for environmental sensing based on the combination of simple and cheap RFID-based sensors and mobile devices like mobile phones with integrated RFID readers. We envision a system, where the mobile nodes cooperatively read sensors installed in the environment as they pass by and transmit the data to a server infrastructure. To achieve quality requirements on the one hand, and on the other hand efficiency in terms of communication cost and energy consumption, this paper presents several algorithms for coordinating update operations. Mobile nodes form an ad-hoc network for the cooperative management of requested update times to meet the desired update interval and to avoid redundant sensor reading and collisions during read operations. Besides this decentralized coordination algorithm, we also show a complementary algorithm that exploits infrastructure based coordination. By extensive simulations we show that our algorithms achieve a high quality of sensor updates where nearly 100\% of the possible updates are performed. Moreover, the algorithms achieve a very high energy efficiency allowing for several hundred hours of operation assuming a typical battery of a mobile phone.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-24&engl=0}
}
@inproceedings {INPROC-2009-141,
   author = {Andreas Grau and Klaus Herrmann and Kurt Rothermel},
   title = {{Exploiting Emulation Testbeds for Security Experiments}},
   booktitle = {Proceedings of the Workshop on Experimental platforms for Internet resilience, security and stability research (invited paper)},
   address = {Br{\"u}ssel},
   publisher = {JRC European Commission},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--2},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2009},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-141/INPROC-2009-141.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Security, resilience and stability test are an important step to protect the information and communication-based digital society. Experimental platforms allow researchers to evaluate todays and tomorrows internet architectures, protocols and applications. However, selecting the most adequate platform is difficult. In this paper we first present a common used approach based on real world testbeds. We identify a couple of problem coming around with this approach and show how emulation-based testbeds can avoids them. Finally we present an hybrid approach to combine the benefits of both systems to provide a scalable, repeatable, controllable, flexible and secure experimental platform.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-141&engl=0}
}
@inproceedings {INPROC-2009-07,
   author = {Ralph Lange and Nazario Cipriani and Lars Geiger and Matthias Gro{\ss}mann and Harald Weinschrott and Andreas Brodt and Matthias Wieland and Stamatia Rizou and Kurt Rothermel},
   title = {{Making the World Wide Space Happen: New Challenges for the Nexus Context Platform}},
   booktitle = {Proceedings of the 7th Annual IEEE International Conference on Pervasive Computing and Communications (PerCom '09). Galveston, TX, USA. March 2009},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--4},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   keywords = {Nexus; context; mobile context-aware applications; context-awareness; context management; World Wide Space; stream-processing; situation recognition; reasoning; workflows; quality of context},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications,     H.3.4 Information Storage and Retrieval Systems and Software,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-07/INPROC-2009-07.pdf,     http://www.nexus.uni-stuttgart.de/,     http://dx.doi.org/10.1109/PERCOM.2009.4912782},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {Context-aware applications rely on models of the physical world. Within the Nexus project, we envision a World Wide Space which provides the conceptual and technological framework for integrating and sharing such context models in an open, global platform of context providers. In our ongoing research we tackle important challenges in such a platform including distributed processing of streamed context data, situation recognition by distributed reasoning, efficient management of context data histories, and quality of context information. In this paper we discuss our approach to cope with these challenges and present an extended Nexus architecture.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-07&engl=0}
}
@inproceedings {INPROC-2009-06,
   author = {Ralph Lange and Tobias Farrell and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Remote Real-Time Trajectory Simplification}},
   booktitle = {Proceedings of the 7th Annual IEEE International Conference on Pervasive Computing and Communications (PerCom '09). Galveston, TX, USA. March 2009},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   keywords = {Remote trajectory simplification; tracking; dead reckoning; moving objects database; MOD; line simplification},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-06/INPROC-2009-06.pdf,     http://dx.doi.org/10.1109/PERCOM.2009.4912767},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Moving objects databases (MODs) have been proposed for managing trajectory data, an important kind of information for pervasive applications. To save storage capacity, a MOD generally stores simplified trajectories only. A simplified trajectory approximates the actual trajectory of the mobile object according to a certain accuracy bound. In order to minimize the costs of communicating position information between mobile object and MOD, the trajectory simplification should be performed by the mobile object. To assure that the MOD always has a valid simplified trajectory of the remote object, we propose the generic remote trajectory simplification protocol (GRTS) allowing for computing and managing a simplified trajectory in such a system in real-time. We show how to combine GRTS with existing line simplification algorithms for computing the simplified trajectory and analyze trade-offs between the different algorithms. Our evaluations show that GRTS outperforms the two existing approaches by a factor of two and more in terms of reduction efficiency. Moreover, on average, the reduction efficiency of GRTS is only 12\% worse compared to optimal offline simplification.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-06&engl=0}
}
@inproceedings {INPROC-2009-04,
   author = {Andreas Benzing and Klaus Herrmann and Boris Koldehofe and Kurt Rothermel},
   title = {{Identifying the Challenges in Reducing Latency in GSN using Predictors}},
   booktitle = {Workshops der Wissenschaftlichen Konferenz Kommunikation in Verteilten Systemen 2009 (WowKiVS 2009)},
   editor = {Tiziana Margaria and Julia Padberg and Gabriele Taentzer},
   address = {Kassel},
   publisher = {EASST},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Electronic Communications of the EASST},
   volume = {17},
   pages = {1--6},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   issn = {1863-2122},
   keywords = {Global Sensor Networks, Wireless Sensor Networks, Predictors},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-04/INPROC-2009-04.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Simulations based on real-time data continuously gathered from sensor networks all over the world have received growing attention due to the increasing availability of measured data. Furthermore, predictive techniques have been employed in the realm of such networks to reduce communication for energy-efficiency. However, research has focused on the high amounts of data transferred rather than latency requirements posed by the applications. We propose using predictors to supply data with low latency as required for accurate simulations. This paper investigates requirements for a successful combination of these concepts and discusses challenges that arise.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-04&engl=0}
}
@inproceedings {INPROC-2009-03,
   author = {Adnan Tariq and Boris Koldehofe and Gerald Koch and Kurt Rothermel},
   title = {{Providing Probabilistic Latency Bounds for Dynamic Publish/Subscribe Systems}},
   booktitle = {Proceedings of the 16th ITG/GI Conference on Kommunikation in Verteilten Systemen 2009 (KiVS 2009)},
   address = {Kassel, Germany},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2009},
   doi = {10.1007/978-3-540-92666-5_13},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-03/INPROC-2009-03.pdf,     http://dx.doi.org/10.1007/978-3-540-92666-5_13},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In the context of large decentralized many-to-many communication systems it is impractical to provide realistic and hard bounds for certain QoS metrics including latency bounds. Nevertheless, many applications can yield better performance if such bounds hold with a given probability. In this paper we show how probabilistic latency bounds can be applied in the context of publish/subscribe. We present an algorithm for maintaining individual probabilistic latency bounds in a highly dynamic environment for a large number of subscribers. The algorithm consists of an adaptive dissemination algorithm as well as a cluster partitioning scheme. Together they ensure i) adaptation to the individual latency requirements of subscribers under dynamically changing system properties, and ii) scalability by determining appropriate clusters according to available publishers in the system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-03&engl=0}
}
@inproceedings {INPROC-2008-98,
   author = {Jos{\'e} Mocito and Briones-Garc{\'\i}a J. Alfonso and Boris Koldehofe and Hugo Miranda and Lu{\'\i}s Rodrigues},
   title = {{Geographical distribution of subscriptions for Content-based Publish/Subscribe in MANETs}},
   booktitle = {Proceedings of the Middleware'08 Companion},
   address = {Leuven, Belgium},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2008},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Establishing content-based publish/subscribe in the resource constrained and failure prone environment of Mobile Ad-Hoc Networks (MANETs) is a highly challenging task. Movement of nodes and network partitioning can require frequent and possibly expensive reorganizations of the publish/subscribe system. Many approaches towards publish/subscribe in MANETs either rely explicitly on location information, or are characterized by a high subscription and publication overhead. In this paper we present preliminary research on how geographical distribution of subscriptions may help to overcome some shortcomings of both approaches.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-98&engl=0}
}
@inproceedings {INPROC-2008-90,
   author = {Stephan Schuhmann and Lars V{\"o}lker},
   title = {{Combining Passive Autoconfiguration and Anomaly-based Intrusion Detection in Ad-hoc Networks}},
   booktitle = {Proceedings of the 8th International Workshop on Applications and Services in Wireless Networks (ASWN 2008); Kassel, Germany, October 9-10, 2008},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {87--95},
   type = {Workshop-Beitrag},
   month = {Oktober},
   year = {2008},
   keywords = {MANET; Intrusion Detection; Anomalies; OLSR},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-90/INPROC-2008-90.pdf,     http://dx.doi.org/10.1109/ASWN.2008.14},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Two essential services of Ad-hoc networks are IP address autoconfiguration and intrusion detection systems. Since both autoconfiguration and intrusion detection may base their decisions on routing protocol anomalies, their interdependencies can cause problems. In this paper, we present our approach to efficiently combine autoconfiguration and intrusion detection, and present our enhancements in attack detection for an autoconfiguration system. We have identified anomalies indicating specific attacks, implemented suitable anomaly detectors, and evaluated our system. The results show that it is possible to detect both the attacks and IP address conflicts in an efficient way.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-90&engl=0}
}
@inproceedings {INPROC-2008-84,
   author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Scalable Processing of Trajectory-Based Queries in Space-Partitioned Moving Objects Databases}},
   booktitle = {Proceedings of the 16th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM GIS 2008)},
   address = {Irvine, CA, USA},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2008},
   keywords = {spatio-temporal indexing; moving objects database; MOD; trajectory-based query; distributed query processing},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-84/INPROC-2008-84.pdf,     http://doi.acm.org/10.1145/1463434.1463474},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Space-partitioned Moving Objects Databases (SP-MODs) allow for the scalable, distributed management of large sets of mobile objects' trajectories by partitioning the trajectory data to a network of database servers. Processing a spatio-temporal query q therefore requires efficiently routing q to the servers storing the affected trajectory segments. With a coordinate-based query - like a spatio-temporal range query - the relevant servers are directly determined by the queried range. However, with trajectory-based queries - like retrieving the distance covered by a certain object during a given time interval - the relevant servers depend on actual movement of the queried object. Therefore, efficient routing mechanisms for trajectory-based queries are an important challenge in SP-MODs. In this paper, we present the Distributed Trajectory Index (DTI) that allows for such efficient query routing by creating an overlay network for each trajectory. We further present an enhanced index called DTI+S. It accelerates the processing of queries on aggregates of dynamic attributes, like the maximum speed during a time interval, by augmenting DTI with summaries of trajectory segments. Our simulations with a network of 1000 database servers show that DTI+S can reduce the overall processing time by more than 98\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-84&engl=0}
}
@inproceedings {INPROC-2008-83,
   author = {Faraz Memon and Daniel Tiebler and Frank D{\"u}rr and Kurt Rothermel and Marco Tomsu and Peter Domschitz},
   title = {{OID: Optimized Information Discovery using Space Filling Curves in P2P Overlay Networks}},
   booktitle = {Proceedings of 14th International Conference on Parallel and Distributed Systems (ICPADS'08)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {311--319},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2008},
   isbn = {978-0-7695-3434-3},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     C.2.3 Network Operations,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-83/INPROC-2008-83.pdf,     http://dx.doi.org/10.1109/ICPADS.2008.57},
   contact = {faraz.memon@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we present the system design and evaluation of a Space-Filling Curve (SFC)-based P2P information discovery system OID. The OID system uses multiple SFCs to significantly optimize the performance of multi-attribute range queries, particularly for applications with a large number of data attributes where a single big SFC-based index is inefficient. The basic idea is to have multiple SFCbased indices and select the best one to perform a query. We also introduce two tree-based query optimizations that increase the scalability of the system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-83&engl=0}
}
@inproceedings {INPROC-2008-70,
   author = {Stephan Schuhmann and Klaus Herrmann and Kurt Rothermel},
   title = {{A Framework for Adapting the Distribution of Automatic Application Configuration}},
   booktitle = {Proceedings of the 2008 ACM International Conference on Pervasive Services (ICPS 2008), Sorrento, Italy, July 6-10, 2008},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {163--172},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2008},
   keywords = {Adaptivity; Components; Middleware; Pervasive Computing; Application Configuration},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-70/INPROC-2008-70.pdf,     http://doi.acm.org/10.1145/1387269.1387297},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Numerous current research projects deal with the issue of automatic application configuration in pervasive computing scenarios. While completely distributed configuration is inevitable in infrastructure-less ad hoc scenarios, many realistic pervasive application scenarios are located in heterogeneous environments where additional computation power of resource-rich devices can be utilized. However, most of the current projects either focus solely on smart environments which rely on additional infrastructure devices, or they address ad hoc environments and treat all involved devices as equal. This leads to suboptimal results in case of present resource-rich devices, as their additional computation power is not exploited. In this paper, we present a framework that is based on clustering and allows the efficient and flexible support of automatic application configuration both in infrastructure-based and ad hoc environments. This is realized by a new concept called Virtual Container that enables the local emulation of remote devices’ functionalities and resources. In our evaluation results, we prove that this concept considerably reduces configuration delays noticeable by the user.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-70&engl=0}
}
@inproceedings {INPROC-2008-69,
   author = {Stephan Schuhmann and Klaus Herrmann and Kurt Rothermel and Jan Blumenthal and Dirk Timmermann},
   title = {{Improved Weighted Centroid Localization in Smart Ubiquitous Environments}},
   booktitle = {Proceedings of the Fifth International Conference on Ubiquitous Intelligence and Computing (UIC 2008), Oslo, Norway, June 23-25, 2008},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {5061},
   pages = {20--34},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2008},
   keywords = {Weighted Centroid Localization; WLAN; Ubiquitous Computing},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-69/INPROC-2008-69.pdf,     http://www.springerlink.com/content/l3l121u67r12445u},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Location-awareness is highly relevant subject in ubiquitous computing, as many applications exploit location information to provide adequate services or adapt to a changing physical environment. While GPS provides reliable outdoor localization, indoor positioning systems present a bigger challenge. Many indoor localization systems have been proposed. However, most of them rely on customized hardware or presume some dedicated infrastructure. In this paper, we focus on WLAN-based localization in smart ubiquitous environments. We propose an improved scheme of the Weighted Centroid Localization (WCL) algorithm that is robust and provides higher location accuracy than the original WCL algorithm. The improvements are based on the use of dynamic weighting factors that are solely dependent on the correlation of the Received Signal Strength Indicators of the received beacon signals. Compared to the original WCL scheme, our approach does not increase requirements to the environment. Real-world experiments in a typical environment that we report on in this paper confirm that the increased location accuracy determined in previous calculations is reproducible in a realistic noisy environment. This provides a simple, cost-efficient, and battery-conserving, but yet adequate technique for getting the accurate location information of mobile devices.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-69&engl=0}
}
@inproceedings {INPROC-2008-68,
   author = {Saukh Olga and Robert Sauter and Matthias Gauger and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{On Boundary Recognition without Location Information in Wireless Sensor Networks}},
   booktitle = {Proceedings of the 2008 International Conference on Information Processing in Sensor Networks (IPSN 2008)},
   address = {Washington, DC, USA},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {207--218},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2008},
   isbn = {978-0-7695-3157-1},
   doi = {http://dx.doi.org/10.1109/IPSN.2008.11},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-68&engl=0}
}
@inproceedings {INPROC-2008-67,
   author = {Matthias Gauger and Olga Saukh and Marcus Handte and Pedro Jos{$\backslash$'e} Marr{$\backslash$'o}n and Andreas Heydlauff and Kurt Rothermel},
   title = {{Sensor-based Clustering for Indoor Applications}},
   booktitle = {Proceedings of the 5th IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2008)},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2008},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   contact = {gauger@cs.uni-bonn.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-67&engl=0}
}
@inproceedings {INPROC-2008-39,
   author = {Jorge A. Briones and Boris Koldehofe and Kurt Rothermel},
   title = {{SPINE: Publish/Subscribe for Wireless Mesh Networks through Self-Managed Intersecting Paths}},
   booktitle = {Proceedings of the 8th International Conference on Innovative Internet Community Systems (I2CS 2008); Schoelcher, Martinique, June 16-18, 2008},
   address = {Schoelcher, Martinique},
   publisher = {online proceedings},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2008},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-39/INPROC-2008-39.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Application deployment on Wireless Mesh Networks (WMNs) is a challenging issue. First it requires communication abstractions that allow for interoperation with Internet applications and second the offered solution should be sensitive to the available resources in the underlying network. Loosely coupled communication abstractions, like publish/subscribe, promote interoperability, but unfortunately are typically implemented at the application layer without considering the available resources at the underlay imposing a significant degradation of application performance in the setting of Wireless Mesh Networks. In this paper we present SPINE, a content-based publish/subscribe system,   which considers the particular challenges of deploying application-level services in Wireless Mesh Networks. SPINE is designed to reduce the overhead which stems from both publications and reconfigurations, to cope with the inherent capacity limitations on communication links as well as with mobility of the wireless mesh-clients. We demonstrate the effectiveness of SPINE by comparison with traditional approaches in implementing content-based publish/subscribe.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-39&engl=0}
}
@inproceedings {INPROC-2008-37,
   author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Online Trajectory Data Reduction using Connection-preserving Dead Reckoning}},
   booktitle = {Proceedings of the Fifth Annual International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services: MobiQuitous '08; Dublin, Ireland, July 21-25, 2008},
   publisher = {ICST},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2008},
   isbn = {978-963-9799-21-9},
   keywords = {Online trajectory reduction; dead reckoning; MOD},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-37/INPROC-2008-37.pdf,     http://portal.acm.org/citation.cfm?id=1595044},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Moving objects databases (MODs) store objects’ trajectories by spatiotemporal polylines that approximate the actual movements given by sequences of sensed positions. Determining such a polyline with as few vertices as possible under the constraint that it does not deviate by more than a certain accuracy bound epsilon from the sensed positions is an algorithmic problem known as trajectory reduction. A specific challenge is online trajectory reduction, i.e. continuous reduction with position sensing in realtime. This particularly is required for moving objects with embedded position sensors whose movements are tracked and stored by a remote MOD. In this paper, we present Connection-preserving Dead Reckoning (CDR), a new approach for online trajectory reduction. It outperforms the existing approaches by 30 to 50\%. CDR requires the moving objects to temporally store some of the previously sensed positions. Although the storage consumption of CDR generally is small, it is not bounded. We therefore further present CDRM whose storage allocation and execution time per position fix can be adjusted and limited. Even with very limited storage allocations of less than 1 kB CDRM outperforms the existing approach by 20 to 40\%.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-37&engl=0}
}
@inproceedings {INPROC-2008-28,
   author = {Paolo Costa and Daniela Gavidia and Boris Koldehofe and Hugo Miranda and Mirco Musolesi and Orian Riva},
   title = {{When Cars Start Gossiping}},
   booktitle = {Proceedings of the ACM EuroSys 2008 Affilated Workshops},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--4},
   type = {Workshop-Beitrag},
   month = {April},
   year = {2008},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-28&engl=0}
}
@inproceedings {INPROC-2008-15,
   author = {Dominique Dudkowski and Harald Weinschrott and Pedro Jos{\'e} Marr{\'o}n},
   title = {{Design and Implementation of a Reference Model for Context Management in Mobile Ad-Hoc Networks}},
   booktitle = {Proceedings of the International Workshop on Data Management for Wireless and Pervasive Communications (DMWPC2008); Gino-wan, Okinawa, Japan, March, 2008},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {832--837},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2008},
   keywords = {context; data management; MANET; reference model; hybrid system},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-15/INPROC-2008-15.pdf,     http://www.computer.org/portal/web/csdl/doi/10.1109/WAINA.2008.72},
   contact = {harald.weinschrott@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The fundamental paradigm of context-aware computing has lead to a diversity of conceivable context-based applications. In order to support these applications, efficient and scalable context management platforms have become utterly important. In this paper we propose a layered reference model that encapsulates suitable abstractions to tackle the complexity of context management in mobile ad-hoc networks. For each layer, we outline strategies and mechanisms we have developed to manage context information efficiently so that it can readily be used by context-based services and applications in these networks. In addition, we discuss refinements of the current model that we currently investigate, which are related to data semantics such as context quality and expressive location models, performance enhancement by adaptation, and aspects regarding the integration of ad-hoc context management with infrastructure-based systems leading to a hybrid system structure.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-15&engl=0}
}
@inproceedings {INPROC-2008-145,
   author = {Matthias Gauger and Pedro Jos{\'e} Marr{\'o}n and Marcus Handte and Olga Saukh and Daniel Minder and Andreas Lachenmann and Kurt Rothermel},
   title = {{Integrating Sensor Networks in Pervasive Computing Environments Using Symbolic Coordinates}},
   booktitle = {Proceedings of the Third International Conference on Communication System Software and Middleware (COMSWARE 2008)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2008},
   keywords = {wireless sensor network; pervasive computing; routing; symbolic coordinates},
   language = {Englisch},
   cr-category = {C.3 Special-Purpose and Application-Based Systems,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-145/INPROC-2008-145.pdf,     http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4554476},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Wireless sensor networks can monitor different types of physical phenomena and are able to provide a diverse set of context data to interested clients. Allowing mobile pervasive computing devices to access such data requires solutions for routing messages between mobile devices and the static sensor network. This paper presents a novel approach that addresses this problem with the help of symbolic coordinates. It requires only a small amount of topology information distributed in the network and allows mobile devices to send messages to arbitrary areas. The routing task is split among the client nodes, which specify a symbolic source route, and the sensor nodes that handle node-to-node routing. The paper describes the algorithm, specific challenges associated with its design and gives an extensive evaluation of the approach and its properties, showing that the use of symbolic coordinates in these environments is a viable alternative to more traditional types of routing.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-145&engl=0}
}
@inproceedings {INPROC-2008-14,
   author = {Matthias Gauger and Daniel Minder and Pedro Jos{\'e} Marr{\'o}n and Arno Wacker and Andreas Lachenmann},
   title = {{Prototyping Sensor-Actuator Networks for Home Automation}},
   booktitle = {Proceedings of the 3rd Workshop on Real-World Wireless Sensor Networks (REALWSN 2008)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2008},
   keywords = {sensor-actuator networks; home automation; prototyping},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     B.4.1 Data Communications Devices},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Integrating actuators into sensor networks is often considered to be the next logical step in the evolution of wireless sensor networks. However, few practical examples of such sensor and actuator networks have been demonstrated so far. In this paper, we present a prototype system that supports the easy prototyping of such applications in the area of home automation. We demonstrate the utility of this system with a simple light control application built on top of it. We also report first experiences and insights gained with the help of real-world experiments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-14&engl=0}
}
@inproceedings {INPROC-2008-123,
   author = {Matthias Gauger and Olga Saukh and Marcus Handte and Pedro Jos{\'e} Marr{\'o}n and Andreas Heydlauff and Kurt Rothermel},
   title = {{Sensor-based Clustering for Indoor Applications}},
   booktitle = {Proceedings of the European Conference on Wireless Sensor Networks (EWSN 2008), Poster/Demo session},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2008},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The lifetime requirements on wireless sensor networks often require the redundant deployment of sensor nodes with appropriate management mechanisms based on node clustering. Yet, existing clustering approaches do not take the primary task of sensor networks into account: performing relevant measurements. They usually form 'arbitrary' clusters, e.g., using connectivity information, and thus, the resulting measurements are often of only limited use to the applications. This problem can be avoided by considering application-specific semantics. For indoor applications, the notion of a room provides a natural unit of clustering since walls are constructed deliberately to ensure locality. This paper shows that it is feasible to automatically create clusters that reflect boundaries between rooms by analyzing the measurements of inexpensive, broadly available sensors. The paper first analyzes the applicability of statistical clustering methods and based on this analysis, it proposes and evaluates a lightweight approach to determine clusters in real deployments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-123&engl=0}
}
@inproceedings {INPROC-2008-122,
   author = {Matthias Gauger and Olga Saukh and Marcus Handte and Pedro Jos{\'e} Marr{\'o}n and Andreas Heydlauff and Kurt Rothermel},
   title = {{Sensor-based Clustering for Indoor Applications}},
   booktitle = {Proceedings of the 5th IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2008)},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {478--486},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2008},
   isbn = {978-1-4244-1777-3},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-122/INPROC-2008-122.pdf,     http://ieeexplore.ieee.org/search/srchabstract.jsp?arnumber=4557787},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The lifetime requirements on wireless sensor networks often require the redundant deployment of sensor nodes with appropriate management mechanisms based on node clustering. Yet, existing clustering approaches do not take the primary task of sensor networks into account: performing relevant measurements. They usually form 'arbitrary' clusters, e.g., using connectivity information, and thus, the resulting measurements are often of only limited use to the applications. This problem can be avoided by considering application-specific semantics. For indoor applications, the notion of a room provides a natural unit of clustering since walls are constructed deliberately to ensure locality. This paper shows that it is feasible to automatically create clusters that reflect boundaries between rooms by analyzing the measurements of inexpensive, broadly available sensors. The paper first analyzes the applicability of statistical clustering methods and based on this analysis, it proposes and evaluates a lightweight approach to determine clusters in real deployments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-122&engl=0}
}
@inproceedings {INPROC-2008-113,
   author = {Frank D{\"u}rr and Kurt Rothermel},
   title = {{Kommunikationsprotokolle zur Vermittlung kontextbezogener Informationen auf Basis r{\"a}umlicher Umgebungsmodelle}},
   booktitle = {Proceedings of VDE-Kongress 2008 -- Zukunftstechnologien: Innovationen - M{\"a}rkte - Nachwuchs},
   address = {Munich, Germany},
   publisher = {VDE Verlag GmbH},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2008},
   isbn = {978-3-8007-3126-8},
   keywords = {contextcast; geocast; Protokoll; protocol; kommunikation; communication; location-based; context-aware; ortsbezogen; kontextbezogen; Ort; Kontext; lokationsbasiert; service; Dienst},
   language = {Deutsch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-113/INPROC-2008-113.pdf,     http://www.vde-verlag.de/proceedings-en/453126101.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In diesem Artikel stellen wir ein neuartiges kontextbezogenes Kommunikationsparadigma namens Contextcast vor. Contextcast erm{\"o}glicht das selektive Senden von Nachrichten an Teilnehmer mit einem bestimmten Kontext, wobei der Kontext eines Teilnehmers beispielsweise durch seinen Aufenthaltsort, seine Interessen oder seine Situation bestimmt ist. Typische Anwendungen f{\"u}r Contextcast sind die gezielte Verteilung von Warnmeldungen, Touristeninformationen oder Veranstaltungshinweise. Wir pr{\"a}sentieren zun{\"a}chst Konzepte zur effizienten Vermittlung von ortsbezogenen Informationen (Geocast) und diskutieren anschlie{\ss}end notwendige Erweiterungen f{\"u}r die effiziente Realisierung der Contextcast-Kommunikation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-113&engl=0}
}
@inproceedings {INPROC-2008-110,
   author = {Frank D{\"u}rr and Jonas Palauro and Lars Geiger and Ralph Lange and Kurt Rothermel},
   title = {{Ein kontextbezogener Instant-Messaging-Dienst auf Basis des XMPP-Protokolls}},
   booktitle = {5. GI/ITG KuVS Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste. N{\"u}rnberg. September 2008},
   address = {N{\"u}rnberg},
   publisher = {Georg-Simon-Ohm-Hochschule N{\"u}rnberg},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Sonderdruck Schriftenreihe der Georg-Simon-Ohm-Hochschule N{\"u}rnberg},
   volume = {42},
   pages = {23--28},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2008},
   issn = {1867-5433},
   keywords = {Nexus; Instant-Messaging; Kontextbezug; context-awareness; Contextcast; XMPP},
   language = {Deutsch},
   cr-category = {H.4.3 Information Systems Applications Communications Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-110/INPROC-2008-110.pdf,     http://www.nexus.uni-stuttgart.de/,     http://www.wireless-earth.de/fg_lbs/meeting_5/meeting_5.html},
   contact = {frank.duerr@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Dieser Beitrag beschreibt die Verteilung kontextbezogener Informationen mittels eines erweiterten Instant-Messaging-Dienstes. Dieser Dienst erm{\"o}glicht das Senden von Nachrichten an alle Teilnehmer, die einen bestimmten Kontext besitzen und sich z.B. an einem bestimmten Ort aufhalten oder bestimmte Interessen besitzen. Als Basis dient das Extensible Messaging and Presence Protokoll (XMPP) sowie ein XMPP-basierter Instant-Messaging-Dienst. Wir beschreiben Protokoll- und Architekturerweiterungen f{\"u}r die Integration von Kontextinformationen in das XMPP-Protokoll und die Server-Infrastruktur. Der erweiterte Dienst unterst{\"u}tzt insbesondere die Server-seitige Filterung von Nachrichten aufgrund von Kontextinformationen und erm{\"o}glicht dadurch die effiziente Nachrichtenverteilung.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-110&engl=0}
}
@inproceedings {INPROC-2008-103,
   author = {Manuel Gonzalo and Klaus Herrmann and Kurt Rothermel},
   title = {{Self-Adaptive Load Balancing for Many-To-Many Communication in Wireless Sensor Networks}},
   booktitle = {Proceedings of the 7th GI/ITG KuVS Fachgespr{\"a}ch ``Drahtlose Sensornetze''},
   address = {Berlin},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {64--67},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2008},
   keywords = {WSN; multisink; routing; many to many; load balancing},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design},
   contact = {manuel.gonzalo@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {New scenarios in wireless sensor networks, where several independent sinks can ask for different kinds of data, are currently emerging. Former algorithms that route data to a centralized sink, are not appropriate for these scenarios. First solutions for these multi-source to multi-sink scenarios simply create independent trees for each source. As a result, some nodes become hot-spots, since they are included in several trees, whereas nodes around them remain unused. In this paper, we propose a new algorithm that balances the load evenly in the network, extending the network lifetime, while still providing a small delay in packet delivery. Based on the information of one-hop neighbors and the number of hops to the sinks, the algorithm attempts to reduce both the delay and the power consumption. We present the cost function used to select the next hop(s) towards the sinks. The evaluation of the protocol demonstrates its ability to fulfill its target.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-103&engl=0}
}
@inproceedings {INPROC-2008-102,
   author = {Klaus Herrmann and Kurt Rothermel},
   title = {{Developing user-responsive mobile applications}},
   booktitle = {PerAda Magazine},
   publisher = {Online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Workshop-Beitrag},
   month = {Oktober},
   year = {2008},
   isbn = {http://www.perada-magazine.eu/view.php?article=1270-2008-09-19&category=Mobile+Applications},
   keywords = {ALLOW; pervasive adaptation; flow attachment; flow distribution; context-aware flows; horizontal adaptation; vertical adaptation},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-102/INPROC-2008-102.pdf,     http://www.perada-magazine.eu/view.php?article=1270-2008-09-19&category=%20Mobile+Applications},
   contact = {Klaus.Herrmann@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {A novel workflow-based approach may one day enable adaptive programs to unobtrusively assist people with everyday tasks.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-102&engl=0}
}
@inproceedings {INPROC-2008-101,
   author = {Klaus Herrmann and Kurt Rothermel and Gerd Kortuem and Dulay Naranker},
   title = {{Adaptable Pervasive Flows - An Emerging Technology for Pervasive Adaptation}},
   booktitle = {Proceedings of the Workshop on Pervasive Adaptation at the Second IEEE International Conference on Self-Adaptive and Self-Organizing Systems (SASO 2008)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Workshop-Beitrag},
   month = {Oktober},
   year = {2008},
   keywords = {ALLOW; pervasive computing; pervasive adaptation; flow distribution; flow attachment; context-aware flows; horizontal adaptation; vertical adaptation},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-101/INPROC-2008-101.pdf,     http://dx.doi.org/10.1109/SASOW.2008.25},
   contact = {Klaus.Herrmann@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The era of pervasive computing brings with it a grand challenge: Pervasive applications must adapt to the dynamics entailed in human behavior and constantly changing computing environments. In this paper, we propose Adaptable Pervasive Flows as a novel technology that goes far beyond existing approaches for adapting pervasive computing systems. APFs model applications in a fashion similar to classical workflows while being situated in the real world. The notable advantage of this is that applications as well as their environment can be adapted proactively based on knowledge about future tasks. We introduce the visions, concepts, and challenges of this emerging approach.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-101&engl=0}
}
@inproceedings {INPROC-2008-10,
   author = {Stephan Schuhmann and Klaus Herrmann and Kurt Rothermel},
   title = {{Direct Backtracking: An Advanced Adaptation Algorithm for Pervasive Applications}},
   booktitle = {Proceedings of the 21st International Conference on Architecture of Computing Systems (ARCS 2008); Dresden, Germany, February 25-28, 2008},
   editor = {Uwe et al. Brinkschulte},
   address = {Berlin Heidelberg},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {4934},
   pages = {53--67},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2008},
   isbn = {978-3-540-78152-3},
   keywords = {Pervasive Computing; Adaptation; Configuration; Backtracking; Pervasive Applications},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-10/INPROC-2008-10.pdf,     http://www.springerlink.com/content/167w160l00445832},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The adaptation of pervasive applications is in the focus of many current research projects. While decentralized adaptation is mandatory in infrastructureless ad hoc scenarios, most realistic pervasive application scenarios are situated in heterogeneous environments where additional computation power of resource-rich devices can be exploited. Therefore, we propose a hybrid approach to application configuration that applies centralized as well as decentralized configuration as appropriate in the given environment. In this paper we introduce the Direct Backtracking algorithm that represents an efficient way for centralized configuration and adaptation of pervasive applications in heterogeneous scenarios. In our evaluation, we show that compared with other centralized algorithms, our algorithm significantly reduces adaptation latency as it avoids unnecessary adaptations that arise in many other backtracking algorithms, without significantly increasing memory waste. This is achieved by introducing two mechanisms: 1. proactive backtracking avoidance and 2. intelligent backtracking.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-10&engl=0}
}
@inproceedings {INPROC-2008-07,
   author = {Andreas Grau and Steffen Maier and Klaus Herrmann and Kurt Rothermel},
   title = {{Time Jails: A Hybrid Approach to Scalable Network Emulation}},
   booktitle = {22nd ACM/IEEE/SCS Workshop on Principles of Advanced and Distributed Simulation (PADS 2008)},
   publisher = {IEEE Computer Society; ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {7--14},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2008},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-07/INPROC-2008-07.pdf,     http://dx.doi.org/10.1109/PADS.2008.19},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {It is essential to evaluate the performance of newly developed distributed software and network protocols. Network emulation enables reproducible evaluation of unmodified real implementations. Software built for distributed systems, such as a large scale peer-to-peer system, requires evaluation scenarios with thousands of communicating nodes. Two approaches for scaling network emulation to such scenario sizes have been proposed in the literature: node virtualization and time virtualization. Node virtualization allows maximizing the utilization of standard hardware used for emulation experiments. Time virtualization enables trading experiment duration for virtually increased resources of the hardware. It stands to reason that a combination of those two approaches may increase scalability even further. However, in existing combinations, either node virtualization implies relatively high overhead or time virtualization requires modifications of the test subject implementation. In this paper, we present a novel hybrid approach called Time Virtualized Emulation Environment (TVEE). It integrates node virtualization with low overhead and time virtualization, which is transparent to the execution of test subjects. We introduce virtual time based on epochs to enable better dynamic hardware utilization during long lasting experiments. Additionally, a mechanism similar to soft timers ensures an accurate reproduction of network properties in the time virtualized emulation. Our evaluations show the accuracy and scalability of time virtualized network emulation. Comparing TCP throughput, TVEE outperforms other approaches using an event based virtual time by an order of magnitude.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-07&engl=0}
}
@inproceedings {INPROC-2008-06,
   author = {Gerald G. Koch and Boris Koldehofe and Kurt Rothermel},
   title = {{Higher confidence in event correlation using uncertainty restrictions}},
   booktitle = {28th IEEE International Conference on Distributed Computing Systems Workshops (ICDCSW'08); 2008},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {417--422},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2008},
   issn = {1545-0678},
   doi = {http://dx.doi.org/10.1109/ICDCS.Workshops.2008.22},
   keywords = {event correlation, uncertainty restriction},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-06/INPROC-2008-06.pdf,     http://dx.doi.org/10.1109/ICDCS.Workshops.2008.22},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Distributed cooperative systems that use event notification for communication can benefit from event correlation within the notification network. In the presence of uncertain data, however, correlation results easily become unreliable. The handling of uncertainty is therefore an important challenge for event correlation in distributed event notification systems. In this paper, we present a generic correlation model that is aware of uncertainty. We propose uncertainty constraints that event correlation can take into account and show how they can lead to higher confidence in the correlation result. We demonstrate that the application of this model allows to obtain a qualitative description of event correlation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-06&engl=0}
}
@inproceedings {INPROC-2008-03,
   author = {Frank D{\"u}rr and Kurt Rothermel},
   title = {{An Adaptive Overlay Network for World-wide Geographic Messaging}},
   booktitle = {Proceedings of the 22nd IEEE International Conference on Advanced Information Networking and Applications (AINA 2008); Gino-wan, Okinawa, Japan, March 25-28, 2008},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {875--882},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2008},
   keywords = {geocast; overlay network; communication; protocol; location-based service; geographic communication; networking; context; context-aware systems},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-03/INPROC-2008-03.pdf,     http://dx.doi.org/10.1109/AINA.2008.67},
   contact = {frank.duerr@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we propose an overlay network supporting world-wide geographic messaging. Our approach is based on hierarchical symbolic coordinates like /usa/fl/miami/. Although hierarchical network topologies lend themselves to the implementation of such overlay networks, they may lead to bottlenecks at the root of the hierarchy, long message paths, and inefficient bandwidth utilization. To avoid these problems, we propose an overlay network that adapts its structure to the users' communication patterns by dynamically adding shortcut`` links to the hierarchy leading to a routing mesh. We present an algorithm that carefully selects shortcuts based on their utility to assure short message paths on the one hand and to reduce the induced overhead on the other hand. Through simulations we show that this approach decreases the average path length significantly and reduces network load to about 50\% compared to hierarchical routing.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-03&engl=0}
}
@inproceedings {INPROC-2007-84,
   author = {Dominique Dudkowski and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{Migration Policies for Location-Centric Data Storage in Mobile Ad-Hoc Networks}},
   booktitle = {Proceedings of the 3rd International Conference on Mobile Ad-hoc and Sensor Networks (MSN'07); Beijing, China, December, 2007},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {197--208},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2007},
   keywords = {location-centric; MANET; migration},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Location-centric data storage is a fundamental paradigm for data management in wireless ad-hoc networks. It guarantees that data is stored at network nodes near specific geometric reference locations in the region where the network is deployed. In mobile ad-hoc networks, maintaining spatial proximity between data and its associated location requires explicit migration mechanisms in order to ``keep the data in place''. In this paper we propose comprehensive policies for data migration that effectively maintain the spatial coherence of data given the particular characteristics of mobile ad-hoc networks. Using extensive simulations we show how the proposed policies outperform related migration approaches over a wide range of system parameter settings, in particular, node density, network dynamics, and migratable data size.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-84&engl=0}
}
@inproceedings {INPROC-2007-83,
   author = {J{\"o}rg H{\"a}hner and Dominique Dudkowski and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{Quantifying Network Partitioning in Mobile Ad Hoc Networks.}},
   booktitle = {Proceedings of the 8th International Conference on Mobile Data Management (MDM 2007), Mannheim, Germany, May 2007},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {174--181},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2007},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The performance of distributed algorithms in mobile ad hoc networks is strongly influenced by the connectivity of the network. In cases where the connectivity is low, network partitioning occurs. The mobility and the density of network nodes as well as the communication technology are fundamental properties that have a large impact on partitioning. A detailed characterization of this behavior helps to improve the performance of distributed algorithms. In this paper we introduce a set of metrics that characterize partitioning in mobile ad hoc networks. Based on an extensive simulation study we show the impact of node mobility, density and transmission range on the proposed metrics for a wide range of network scenarios.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-83&engl=0}
}
@inproceedings {INPROC-2007-73,
   author = {Sebastien Baehni and Rachid Guerraoui and Boris Koldehofe and Maxime Monod},
   title = {{Towards Fair Event Dissemination}},
   booktitle = {Proceedings of the 27th IEEE International Conference on Distributed Computing Systems Workshops (ICDCSW'07)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2007},
   doi = {10.1109/ICDCSW.2007.83},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-73/INPROC-2007-73.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Event dissemination in large scale dynamic systems is typically claimed to be best achieved using decentralized peer-to-peer architectures. The rationale is to have every participant in the system act both as a client (information consumer) and as a server (information dissemination enabler), thus, precluding specific brokers which would prevent scalability and fault-tolerance. We argue that, for such decentralized architectures to be really meaningful, participants should serve the system as much as they benefit from it. That is, the system should be fair in the sense that the extend to which a participant acts as a server should depend on the extend to which it has the opportunity to act as a client. This is particularly crucial in selective information dissemination schemes where clients are not all interested in the same information. In this position paper, we discuss what a notion of fairness could look like, explain why current architectures are not fair, and raise several challenges towards achieving fairness.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-73&engl=0}
}
@inproceedings {INPROC-2007-57,
   author = {The SpoVNet Consortium and Boris Koldehofe and Gerald Georg Koch},
   title = {{SpoVNet: An Architecture for Supporting Future Internet Applications}},
   booktitle = {Proc. 7th W{\"u}rzburg Workshop on IP: Joint EuroFGI and ITG Workshop on ``Visions of Future Generation Networks''},
   address = {W{\"u}rzburg, Germany},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Workshop-Beitrag},
   month = {Juli},
   year = {2007},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-57/INPROC-2007-57.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {This talk presents an approach for providing Spontaneous Virtual Networks (SpoVNets) that enable flexible, adaptive, and spontaneous provisioning of application-oriented and network-oriented services on top of heterogeneous networks. SpoVNets supply new and uniform communication abstractions for future Internet applications so applications can make use of advanced services not supported by today's Internet. We expect that many functions, which are currently provided by SpoVNet on the application layer will become an integral part of future networks. Thus, SpoVNet will transparently use advanced services from the underlying network infrastructure as they become available (e.g., QoS-support in access networks or multicast in certain ISPs), enabling a seamless transition from current to future genera-tion networks without modifying the applications.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-57&engl=0}
}
@inproceedings {INPROC-2007-55,
   author = {Klaus Herrmann},
   title = {{Group Anti-Entropy - Achieving Eventual Consistency in Mobile Service Environments}},
   booktitle = {Proceedings of the 8th IEEE International Conference on Mobile Data Management (MDM'07)},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2007},
   keywords = {mobility, ambient services, data consistency, optimistic replication},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.2 Database Management},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-55/INPROC-2007-55.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Data consistency protocols are vital ingredients of mobile data management systems. Notable research efforts have been spent to find adequate consistency models for allowing mobile and nomadic users to share mutable data. Recently, mobile Ambient Service infrastructures that pose somewhat different requirements have entered the focus of attention. Such services are not as loosely coupled as the afore-mentioned systems, but they still need flexible consistency protocols that may adapt to the current dynamics in the system. We propose an extension to the well-known anti-entropy protocol that makes use of the nature of Ambient Service environments to allow for a flexible consistency management among arbitrary groups of mobile service replicas. We will show that our protocol can exploit the concept of group updates to increase its efficiency in terms of bandwidth usage. Furthermore, we prove that it avoids costly state transfers by means of a simple rule that limits the divergence within the overall set of replicas. Finally, we introduce two simple tunable parameters, and we present experimental results that show how they may be used to shape the characteristics of the protocol.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-55&engl=0}
}
@inproceedings {INPROC-2007-54,
   author = {Gero M{\"u}hl and Matthias Werner and Michael A. Jaeger and Klaus Herrmann and Helge Parzyjegla},
   title = {{On the Definitions of Self-Managing and Self-Organizing Systems}},
   booktitle = {KiVS 2007 Workshop: Selbstorganisierende, Adaptive, Kontextsensitive verteilte Systeme (SAKS 2007)},
   address = {Bern, Switzerland},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Informatik aktuell},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2007},
   keywords = {self-organization, self-management, adaptivity, classification, formal model},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     F.1.1 Models of Computation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-54/INPROC-2007-54.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The management costs of software systems are becoming the dominating cost factor in running IT infrastructures. The main driving force behind this development is the ever-increasing system complexity which is becoming the limiting factor for further development. The fact that human administrators get more and more overstrained by management tasks has led to the idea of systems that manage themselves, i.e., self-managing systems. Another concept that is closely related to selfmanagement is self-organization. Self-organizing software systems often build on bio- and nature-inspired approaches. However, most publications on self-managing or self-organizing systems miss a clear definition of these terms. Even worse, although self-management and self-organization aim at similar goals, their relation still has not been defined properly. In this paper, we approach these problems by introducing a classification of systems that models self-organizing systems as a subclass of selfmanaging systems. The classification builds upon a definition of adaptive systems and introduces self-manageable, self-managing, and selforganizing systems. Our proposal serves as a starting point for further discussions, eventually leading to a better understanding of the terms self-organization and self-management and their interrelationship.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-54&engl=0}
}
@inproceedings {INPROC-2007-53,
   author = {Michael A. Jaeger and Helge Parzyjegla and Gero M{\"u}hl and Klaus Herrmann},
   title = {{Self-Organizing Broker Topologies for Publish/Subscribe Systems}},
   booktitle = {The 22nd Annual ACM Symposium on Applied Computing},
   address = {Seoul, Korea},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {543--550},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2007},
   keywords = {publish/subscribe, adaptable middleware, self-organization, overlay networks},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-53/INPROC-2007-53.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Distributed publish/subscribe systems are usually deployed on top of an overlay network that enables complex routing strategies implemented in the application layer. Up to now, only little effort has been spent on the design of the broker overlay network assuming that it is either static or manually administered. As publish/subscribe systems are increasingly targeted at dynamic environments where client behavior and network characteristics vary over time, static overlay networks lead to suboptimal performance. In this paper, we present a self-organizing broker overlay infrastructure that adapts dynamically to achieve a better efficiency on both, the application and the network layer. This is obtained by taking network metrics as well as notification traffic into account.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-53&engl=0}
}
@inproceedings {INPROC-2007-51,
   author = {Klaus Herrmann},
   title = {{Self-Organizing Replica Placement - A Case Study on Emergence}},
   booktitle = {Proceedings of the first IEEE International Conference on Self-Adaptive and Self-Organizing Systems},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {13--22},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2007},
   keywords = {self-organization, emergence, replica placement, case study},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-51/INPROC-2007-51.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The concept of self-organization is rapidly gaining importance in the area of distributed computing systems. However, we still lack the necessary means for engineering such system in a standardized way since their common properties are rather abstract, and the mechanisms from which self-organization emerges are too diverse. Therefore, it has become common practice to engineer computing systems by taking inspirations from well-known case studies of biological systems. However, the concepts found in such systems are in many cases only partially transferable to the domain of distributed computing systems since biological systems are subject to vastly different constraints compared to those in a computing system. Our contributions in this paper are the following: (i) We present a case study of a self-organizing software system that originates from the domain of distributed computing systems. Therefore, its concepts can be exploited in other distributed computing systems much more directly. (ii) We give a detailed analysis of the emergent properties of the system and the mechanisms by which they arise. (iii) We generalize the mechanisms by which self-organization emerges in this system and present a catalog of design questions that may help engineers in creating arbitrary self-organizing systems.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-51&engl=0}
}
@inproceedings {INPROC-2007-50,
   author = {Klaus Herrmann},
   title = {{Self-Organizing Infrastructures for Ambient Services}},
   booktitle = {Kommunikation in Verteilten Systemen (KiVS), 15. ITG/GI Fachtagung Kommunikation in Verteilten Systemen (KiVS 2007)},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Informatik aktuell},
   pages = {299--306},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2007},
   isbn = {3-540-69961-9},
   keywords = {self-organization, middleware, data consistency, lookup service, mobile ad hoc networks, replica placement, wireless mesh networks},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-50/INPROC-2007-50.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The vision of Ambient Intelligence (AmI) as a new paradigm for supporting the mobile user in his daily activities is currently entering the focus of European research efforts. A high degree of autonomy on the part of the supporting software system is inherent to this vision of omnipresent and continuously running services. However, adequate concepts for creating respective infrastructures that may operate autonomously and in a self-organized fashion are still largely unexplored. We propose the Ad hoc Service Grid (ASG) as a dedicated AmI infrastructure that may be deployed in an ad hoc fashion at arbitrary medium-sized locations (shopping malls, construction sites, trade fairs, etc.). In this paper, we give an overview over our results thus far. We focus on the problems of service placement, discovery and lookup, and data consistency within an ASG environment and show how we have solved these problems with new self-organizing and adaptive algorithms. These vital functions are the basis for the realization of ASG systems and represent an essential contribution to AmI research in general.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-50&engl=0}
}
@inproceedings {INPROC-2007-48,
   author = {Marcus Handte and Klaus Herrmann and Gregor Schiele and Christian Becker and Kurt Rothermel},
   title = {{Automatic Reactive Adaptation of Pervasive Applications}},
   booktitle = {Proceedings of ICPS'07: IEEE International Conference on Pervasive Services},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {214--222},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2007},
   keywords = {adaptivity, components, mobility, optimization},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-48/INPROC-2007-48.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive Computing envisions seamless and distraction-free support for everyday tasks through distributedapplications that leverage the resources of the users' environment. Due to the mobility of users and devices, applications need to adapt continuously to their changing execution environment. Therefore, developers need a suitable framework in order to efficiently create adaptive applications. In this paper, we present and evaluate our approach to adapting a pervasive computing application to changes during its execution. This work is based on the minimal component system PCOM and on an algorithm to fully automate the initial configuration of a componentbased application which we have presented in earlier work. The contribution of this paper is threefold. First, we describe a number of modifications to the component model that are required to enable fully automatic adaptation. Secondly, we propose a simple yet powerful cost model to capture the complexity of specific adaptations. Thirdly, we describe an online optimization heuristic that extends our distributed configuration algorithm in order to choose to a low-cost configuration whenever the current configuration of a pervasive application requires adaptation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-48&engl=0}
}
@inproceedings {INPROC-2007-46,
   author = {Matthias Gauger and Pedro Jos{\'e} Marr{\'o}n and Daniel Kauker and Kurt Rothermel},
   title = {{Low Overhead Assignment of Symbolic Coordinates in Sensor Networks}},
   booktitle = {Proceedings of the IFIP First International Conference on Wireless Sensor and Actor Networks, WSAN'07},
   editor = {Luis Orozco-Barbosa and Teresa Olivares and Rafael Casado and Aurelio Berm{\'u}dez},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {181--192},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2007},
   isbn = {978-0-387-74898-6},
   language = {Englisch},
   cr-category = {C.3 Special-Purpose and Application-Based Systems},
   contact = {gauger@cs.uni-bonn.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Approximate information on the location of nodes in a sensor network is essential to many types of sensor network applications and algorithms. In many cases, using symbolic coordinates is an attractive alternative to the use of geographic coordinates due to lower costs and lower requirements on the available location information during coordinate assignment. In this paper, we investigate different possible methods of assigning symbolic coordinates to sensor nodes. We present a method based on broadcasting coordinate messaging and filtering using sensor events. We show in the evaluation that this method allows a reliable assignment of symbolic coordinates while only generating a low overhead.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-46&engl=0}
}
@inproceedings {INPROC-2007-45,
   author = {Daniel Minder and Pedro Jos{\'e} Marr{\'o}n and Andreas Lachenmann and Kurt Rothermel},
   title = {{Coordinated group adaptation in sensor networks}},
   booktitle = {6. Fachgespr{\"a}ch Sensornetzwerke},
   publisher = {RWTH Aachen},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Technischer Bericht},
   volume = {AIB 2007-11},
   pages = {43--46},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2007},
   issn = {0935-3232},
   keywords = {wireless sensor network; group adaptation; coordination},
   language = {Englisch},
   cr-category = {D.4.7 Operating Systems Organization and Design,     C.2.1 Network Architecture and Design,     C.2.3 Network Operations},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-45/INPROC-2007-45.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In Wireless Sensor Networks, several algorithms are used to perform different functionality, e.g. routing or clock synchronization. Each algorithm is intended for specific network characteristics and user requirements. But the acutal characteristics and requirements may change during system runtime. TinyCubus and particularly its Tiny Data Managment Framework use adaptation to solve this problem. In this paper, we first explain the centralized adaptation process. Then, we examine how this can be done localized in the network. Since coordination between local adaptation decisions is found to be necessary, metrics for this coordination and their dependencies are shown.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-45&engl=0}
}
@inproceedings {INPROC-2007-38,
   author = {Lars Geiger and Frank D{\"u}rr},
   title = {{Kontextbezogene Kommunikation}},
   booktitle = {4. GI/ITG KuVS Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste},
   editor = {J{\"o}rg Roth and Axel K{\"u}pper and Claudia Linnhoff-Popien},
   address = {M{\"u}nchen},
   publisher = {Verlag Dr. Hut},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {22--26},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2007},
   isbn = {978-3-89963-591-1},
   keywords = {Kontext; Kommunikation; Multicast; Nexus},
   language = {Deutsch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.2.4 Distributed Systems,     C.2.6 Internetworking},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-38/INPROC-2007-38.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Verbindet man die Position eines Benutzers mit weiteren Attributen wie beispielsweise Typ, Alter oder Status zu seinem Kontext, so ergeben sich daraus interessante neue Anwendungsm{\"o}glichkeiten. In diesem Artikel soll ein Verfahren vorgestellt werden, wie ein solcher Kontext benutzt werden kann, um Nachrichten an bestimmte Gruppen von Benutzern --- bestimmt durch ihren Kontext --- zu versenden. Ein solcher Kommunikationsmechanismus k{\"o}nnte beispielsweise eingesetzt werden, um Verkehrsnachrichten gezielt an alle Fahrzeuge innerhalb eines bestimmten Gebietes und mit einer bestimmten Fahrtrichtung zu {\"u}bermitteln.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-38&engl=0}
}
@inproceedings {INPROC-2007-35,
   author = {Tobias Farrell and Reynold Cheng and Kurt Rothermel},
   title = {{Energy-Efficient Monitoring of Mobile Objects with Uncertainty-Aware Tolerances}},
   booktitle = {Proceedings of the 11th International Database Engineering and Applications Symposium (IDEAS 2007); Banff, Canada, September 6-8, 2007},
   editor = {Bipin C. Desai and Ken Barker},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {129--140},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2007},
   isbn = {0-7695-2947-X},
   doi = {10.1109/IDEAS.2007.4318097},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4318075&arnumber=4318097},
   contact = {Tobias.Farrell@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In location-based services, continuous queries are often employed to monitor the locations of mobile ob-jects that are determined by sensing devices like GPS receivers. Due to limited battery resources, it is impor-tant for these objects to acquire and report location data only if necessary. We study how these energy-consuming operations can be reduced with a con-trolled impact on query accuracy of continuous range queries (CRQs). Specifically, we develop uncertainty-aware tolerances, which are user-defined error bounds that provide correctness guarantees, with considera-tion of different sources of data uncertainty: sensing uncertainty, sampling uncertainty, and communication delay. Novel algorithms are developed to control carefully when an object should acquire and update a location, while satisfying these tolerances. Extensive simulations validate the effectiveness of our methods.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-35&engl=0}
}
@inproceedings {INPROC-2007-34,
   author = {Tobias Farrell and Ralph Lange and Kurt Rothermel},
   title = {{Energy-efficient Tracking of Mobile Objects with Early Distance-based Reporting}},
   booktitle = {Proceedings of the Fourth Annual International Conference on Mobile and Ubiquitous Systems: Networking and Services (MobiQuitous 2007); Philadelphia, PA, USA, August 6-10, 2007},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2007},
   isbn = {1-4244-1025-8},
   doi = {10.1109/MOBIQ.2007.4450984},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-34/INPROC-2007-34.pdf,     http://www.ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4450969&arnumber=4450984},
   contact = {Tobias.Farrell@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many location-based systems rely on fine-grained tracking of mobile objects that determine their own locations with sensing devices like GPS receivers. For these objects, energy is a very valuable and limited resource. A distance-based reporting protocol can be employed to reduce the energy they consume by sending position updates. However, the energy required for position sensing has not been considered in the past. In this paper, we study how the resulting energy consumption from both sensing and update operations can be reduced for distance-based reporting. We show that significant savings are achieved by sending position updates earlier than actually required. For uniform movement, we derive the minimal power consumption analytically. Subsequently, two novel online heuristics are proposed that control the sending of position updates at runtime. Their effectiveness is validated by extensive simulations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-34&engl=0}
}
@inproceedings {INPROC-2007-15,
   author = {Martin Saternus and Mirko Knoll and Frank D{\"u}rr and Torben Weis},
   title = {{Symstry: Ein P2P-System f{\"u}r Ortsbezogene Anwendungen}},
   booktitle = {Proceedings of 15. ITG/GI - Fachtagung (KiVS 2007)},
   publisher = {VDE-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {99--104},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2007},
   isbn = {ISBN 978-3-8007-2980-7},
   keywords = {peer-to-peer; context-aware system},
   language = {Deutsch},
   cr-category = {H.3.3 Information Search and Retrieval},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-15&engl=0}
}
@inproceedings {INPROC-2007-14,
   author = {Martin Saternus and Torben Weis and Mirko Knoll and Frank D{\"u}rr},
   title = {{A Middleware for Context-Aware Applications and Services Based on Messenger Protocols}},
   booktitle = {Proceedings of the Fifth Annual IEEE International Conference on Pervasive Computing and Communications Workshops (PerComW'07)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {467--471},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2007},
   keywords = {context-aware application; middleware; user interface; messenger},
   language = {Englisch},
   cr-category = {D.2.6 Software Engineering Programming Environments,     H.5.0 Information Interfaces and Presentation General},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Nowadays most context-aware applications are independent proprietary pieces of software. A general framework or middleware deployed in the field does not exist; therefore the implementation of context-aware applications and services assumes the development of the whole application stack for each application. Along these development issues, deployment and privacy problems are to be solved. This imposes the following challenges concerning a middleware for context-aware applications: (1) We need an architecture that allows to implement and deploy services easily on the network. (2) We need a user interface that is widespread, well known to users and allows to mange one’s privacy settings for every single service transparently. In this paper we describe our middleware’s architecture for context-aware applications, based on messenger protocols.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-14&engl=0}
}
@inproceedings {INPROC-2007-133,
   author = {Andreas Lachenmann and Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Kurt Rothermel},
   title = {{Meeting Lifetime Goals with Energy Levels}},
   booktitle = {Proceedings of the 5th ACM Conference on Embedded Networked Sensor Systems (SenSys 2007)},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {131--144},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2007},
   doi = {10.1145/1322263.1322277},
   keywords = {wireless sensor network; energy; lifetime goal; programming abstraction},
   language = {Englisch},
   cr-category = {D.3.3 Programming Language Constructs and Features,     D.4.8 Operating Systems Performance},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-133/INPROC-2007-133.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we present Levels, a programming abstraction for energy-aware sensor network applications. Unlike most previous work it does not try to maximize network lifetime but rather helps to meet user-defined lifetime goals while maximizing application quality. Levels is targeted to applications where there is no redundancy and no node should fail early. With our programming abstraction the application developer defines so-called energy levels. These energy levels form a stack and can be deactivated from top to bottom if the lifetime goal cannot be met otherwise. Each code block within an energy level contains information about its energy consumption, which can be obtained from simulation tools without much effort. The runtime system then uses the data about the energy consumption of the different levels to compute an optimal level assignment for the time remaining. As we show in the evaluation, applications using Levels can accurately meet given lifetime goals and offer good application quality. In addition, the runtime overhead of our system is almost negligible.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-133&engl=0}
}
@inproceedings {INPROC-2007-132,
   author = {Daniel Minder and Andreas Grau and Pedro Jos{\'e} Marr{\'o}n},
   title = {{On Group Formation for Self-Adaptation in Pervasive Systems}},
   booktitle = {Proceedings of the First International Conference on Autonomic Computing and Communication Systems},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2007},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-132/INPROC-2007-132.pdf,     http://portal.acm.org/citation.cfm?doid=1365562.1365584},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Adaptation in Pervasive Computing normally focuses on services or on application behaviour, but the consideration of lower level algorithms in this process can lead to significant performance increase. To perform adaptation of algorithms the concept of context normally used in Pervasive Computing has to be extended. Based on the same context, group formation models are established to group devices with similar relevant context to optimise the adaptation process. In this paper, such group formation models are developed and evaluated. We also draw general conclusions for adaptation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-132&engl=0}
}
@inproceedings {INPROC-2007-13,
   author = {Marcus Handte and Klaus Herrmann and Gregor Schiele and Christian Becker},
   title = {{Supporting Pluggable Configuration Algorithms in PCOM}},
   booktitle = {Perware Workshop at 5th IEEE International Conference on Pervasive Computing and Communications (PerCom)},
   address = {New York, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {472--476},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2007},
   language = {Englisch},
   cr-category = {D.2.11 Software Engineering Software Architectures,     D.1.2 Automatic Programming},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-13/INPROC-2007-13.pdf,     http://dx.doi.org/10.1109/PERCOMW.2007.111},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive Computing envisions distributed applications that optimally leverage the resources present in their ever-changing execution environment. To ease the development of pervasive applications, we have created a pervasive component system (PCOM). PCOM automates the configuration and runtime adaptation of a component-based application using a builtin distributed configuration algorithm. In this paper, we present an architectural extension that allows switching between different algorithms. This enables PCOM to dynamically select an algorithm that suits the computational resources present in an environment. To validate the extended architecture, we compare the overheads of a distributed and a centralized configuration algorithm in two different environments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-13&engl=0}
}
@inproceedings {INPROC-2007-12,
   author = {Gregor Schiele and Marcus Handte and Christian Becker},
   title = {{Good Manners for Pervasive Computing - An Approach Based on the Ambient Calculus}},
   booktitle = {WIP Track at 5th IEEE International Conference on Pervasive Computing and Communications (PerCom)},
   address = {New York, USA},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {589--593},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2007},
   language = {Englisch},
   cr-category = {D.2.7 Software Engineering Distribution, Maintenance, and Enhancement},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {When people interact, they follow distinct rules that coordinate the order of speech, who opens doors, whom and how to greet, and many things more. Such a social codex depends on the milieu -- or ambience -- people are acting in. People breaking the codex are either considered badly educated or foreigners to the ambience -- sometimes even both. In Pervasive Computing a multitude of applications is expected to populate our environment and to follow objects and users throughout their daily journey. Consequently, we will need a new codex -- or manners -- for Pervasive Computing applications that controls the interaction between applications. Such a codex will have to incorporate our existing codices as well as technical aspects. In this work in progress paper we present an approach to extend our prior work on Pervasive Computing system support by specifying interdependencies of applications based on the ambient calculus. This allows specifying and technically enforcing ``manners'' for Pervasive Computing applications.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-12&engl=0}
}
@inproceedings {INPROC-2007-05,
   author = {Steffen Maier and Andreas Grau and Harald Weinschrott and Kurt Rothermel},
   title = {{Scalable Network Emulation: A Comparison of Virtual Routing and Virtual Machines}},
   booktitle = {Proceedings of the IEEE Symposium on Computers and Communications (ISCC'07), Aveiro, Portugal, July 1-4},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {395--402},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2007},
   keywords = {network emulation; performance measurement; virtual machine; virtual routing},
   language = {Englisch},
   cr-category = {C.4 Performance of Systems,     D.4.4 Operating Systems Communications Management,     D.4.8 Operating Systems Performance,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-05/INPROC-2007-05.pdf,     http://dx.doi.org/10.1109/ISCC.2007.4381529},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Performance analysis is a necessary step during the development of distributed applications and communication protocols. Network emulation testbeds provide synthetic, configurable environments for comparative performance measurements of real implementations. However, realistic scenarios require more communicating nodes than usual testbeds are able to provide. In order to enable scalable network emulation, various concepts for the virtualization of nodes have been proposed. The overhead of virtualization strongly impacts the total size of a scenario, that can be emulated on a given testbed. However, the overhead of different virtualization approaches in the context of network emulation has not been compared directly so far. In this paper, we present a comparison of different virtual machine implementations (Xen, User Mode Linux) and our own virtual routing approach (NET). We discuss qualitative evaluation criteria and present a quantitative evaluation showing the efficiency of each approach in a traditional wired infrastructure-based and in a wireless ad hoc network emulation scenario. Our results give insights on which virtualization approach is best suited for which kind of network emulation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-05&engl=0}
}
@inproceedings {INPROC-2007-02,
   author = {Andreas Lachenmann and Pedro Jos{\'e} Marr{\'o}n and Matthias Gauger and Daniel Minder and Olga Saukh and Kurt Rothermel},
   title = {{Removing the Memory Limitations of Sensor Networks with Flash-Based Virtual Memory}},
   booktitle = {Proceedings of the European Conference on Computer Systems (EuroSys 2007)},
   publisher = {EuroSys},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Also published in ACM SIGOPS Operating Systems Review, vol. 41(3), 2007},
   pages = {131--144},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2007},
   language = {Englisch},
   cr-category = {D.4.2 Storage Management,     D.3.4 Programming Languages Processors},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-02/INPROC-2007-02.pdf,     http://www.ipvs.uni-stuttgart.de/abteilungen/vs/forschung/projekte/tinycubus/start},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Virtual memory has been successfully used in different domains to extend the amount of memory available to applications. We have adapted this mechanism to sensor networks, where, traditionally, RAM is a severely constrained resource. In this paper we show that the overhead of virtual memory can be significantly reduced with compile-time optimizations to make it usable in practice, even with the resource limitations present in sensor networks. Our approach, ViMem, creates an efficient memory layout based on variable access traces obtained from simulation tools. This layout is optimized to the memory access patterns of the application and to the specific properties of the sensor network hardware. Our implementation is based on TinyOS. It includes a pre-compiler for nesC code that translates virtual memory accesses into calls of ViMem’s runtime component. ViMem uses flash memory as secondary storage. In order to evaluate our system we have modified nontrivial existing applications to make use of virtual memory. We show that its runtime overhead is small even for large data sizes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-02&engl=0}
}
@inproceedings {INPROC-2007-01,
   author = {Andreas Lachenmann and Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Olga Saukh and Matthias Gauger and Kurt Rothermel},
   title = {{Versatile Support for Efficient Neighborhood Data Sharing}},
   booktitle = {Proceedings of the 4th European Conference on Wireless Sensor Networks (EWSN 2007)},
   editor = {Koen Langendoen and Thiemo Voigt},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {4373},
   pages = {1--16},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2007},
   keywords = {wireless sensor networks; neighborhood data sharing; polite gossiping},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     C.3 Special-Purpose and Application-Based Systems,     D.3.3 Programming Language Constructs and Features},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-01/INPROC-2007-01.pdf,     http://www.ipvs.uni-stuttgart.de/abteilungen/vs/forschung/projekte/tinycubus/start,     http://dx.doi.org/10.1007/978-3-540-69830-2_1},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Many applications in wireless sensor networks rely on data from neighboring nodes. However, the effort for developing efficient solutions for sharing data in the neighborhood is often substantial. Therefore, we present a general-purpose algorithm for this task that makes use of the broadcast nature of radio transmission to reduce the number of packets. We have integrated this algorithm into TinyXXL, a programming language extension for data exchange. This combined system offers seamless support both for data exchange among the components of a single node and for efficient neighborhood data sharing. We show that compared to existing solutions, such as Hood, our approach further reduces the work of the application developer and provides greater efficiency.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-01&engl=0}
}
@inproceedings {INPROC-2006-73,
   author = {Stephan Urbanski and Marcus Handte and Gregor Schiele and Kurt Rothermel},
   title = {{Experience using Processes for Pervasive Computing}},
   booktitle = {Pervasive University Workshop at Informatik 2006},
   editor = {GI},
   publisher = {GI},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--5},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2006},
   language = {Englisch},
   cr-category = {D.2.11 Software Engineering Software Architectures},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive Computing envisions seamless computing support for users while performing their everyday tasks. Many of these tasks are hard to capture by the notion of a single application as their requirements on computing support vary over time. To ease the development of applications for such tasks, we have designed an application model for process-oriented pervasive applications, called Sentient Processes, and a supporting middleware system implementing the flow control for processes. In this paper, we show the capabilities of the Sentient Process model to capture everyday user tasks by the example of a process supporting a student in managing his classes during a term.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-73&engl=0}
}
@inproceedings {INPROC-2006-72,
   author = {Stephan Urbanski and Christian Becker and Kurt Rothermel},
   title = {{Sentient Processes - Process-based Applications in Pervasive Computing}},
   booktitle = {WIP Track at 4th IEEE Conference on Pervasive Computing and Communications (PerCom)},
   editor = {IEEE},
   address = {Pisa, Italy},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--4},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2006},
   language = {Englisch},
   cr-category = {D.2.3 Software Engineering Coding Tools and Techniques,     D.2.11 Software Engineering Software Architectures},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Users' tasks are typically a sequence of steps. Today, the goal of pervasive computing applications - to support users in their tasks by using context information - is only partially met as applications supported by current infrastructures focus on individual steps instead of supporting the coordination of the whole sequence. In this paper, we present an approach for supporting multi-step user tasks by using a process-based application model, called sentient processes. Along with the model, the paper introduces the design of an execution engine for such processes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-72&engl=0}
}
@inproceedings {INPROC-2006-62,
   author = {Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Andreas Lachenmann and Olga Saukh and Matthias Gauger and Robert Sauter and Manuel Gonzalo},
   title = {{Adaption and Cross-Layer Support for Sensor Networks}},
   booktitle = {4. GMM-Workshop Energieautarke Sensorik},
   publisher = {GMM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Fachbericht},
   volume = {51},
   pages = {63--72},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2006},
   isbn = {3-8007-2987-3},
   keywords = {wireless sensor networks; adaptation; cross-layer},
   language = {Englisch},
   cr-category = {D.4.7 Operating Systems Organization and Design,     C.2.1 Network Architecture and Design,     C.3 Special-Purpose and Application-Based Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {-},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-62&engl=0}
}
@inproceedings {INPROC-2006-61,
   author = {Pedro Jos{\'e} Marr{\'o}n and Robert Sauter and Olga Saukh and Matthias Gauger and Kurt Rothermel},
   title = {{Challenges of Complex Data Processing in Real World Sensor Network Deployments}},
   booktitle = {Proceedings of the ACM Workshop on Real-World Wireless Sensor Networks (REALWSN 2006)},
   address = {Uppsala, Sweden},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {43--47},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2006},
   keywords = {Sensor networks; data processing; challenges},
   language = {Englisch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software,     C.2.4 Distributed Systems,     C.3 Special-Purpose and Application-Based Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-61/INPROC-2006-61.pdf,     http://www.ipvs.uni-stuttgart.de/abteilungen/vs/forschung/projekte/tinycubus/start},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Long-term deployments of wireless sensor networks so far have been focused on the periodic gathering of simple sensor readings. However, technological advances allow working with more complex types of data that also create larger data volumes. In this paper we use a real world engineering application to identify a series of challenges related to complex data processing in sensor networks. We present a classification of these challenges and outline a set of preliminary solutions that we are currently in the process of developing for our motivating application.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-61&engl=0}
}
@inproceedings {INPROC-2006-60,
   author = {Matthias Gauger and Pedro Jos{\'e} Marr{\'o}n and Marcus Handte and Kurt Rothermel},
   title = {{Routing in Sensor Networks based on Symbolic Coordinates}},
   booktitle = {5. GI/ITG KuVS Fachgespr{\"a}ch ``Drahtlose Sensornetze''},
   editor = {Pedro Marr{\'o}n},
   address = {Stuttgart},
   publisher = {Universit{\"a}t Stuttgart},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Technischer Bericht},
   volume = {2006/07},
   pages = {81--86},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2006},
   language = {Englisch},
   cr-category = {C.2.3 Network Operations,     C.2.4 Distributed Systems,     C.3 Special-Purpose and Application-Based Systems},
   contact = {Matthias.Gauger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The routing of messages between mobile nodes and a sensor network is an important but challenging task. In this paper we present our approach for this problem that is based on the use of symbolic coordinates and that divides the task among client and sensor nodes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-60&engl=0}
}
@inproceedings {INPROC-2006-55,
   author = {Andreas Lachenmann and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{Efficient Flash-based Virtual Memory for Sensor Networks}},
   booktitle = {5. GI/ITG KuVS Fachgespr{\"a}ch ``Drahtlose Sensornetze''},
   editor = {Pedro Jos{\'e} Marr{\'o}n},
   publisher = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Technical Report},
   volume = {2006/07},
   pages = {27--31},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2006},
   keywords = {Virtual Memory; Wireless Sensor Networks; Flash Memory; Memory Layout},
   language = {Englisch},
   cr-category = {D.4.4 Operating Systems Communications Management,     D.3.4 Programming Languages Processors},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-55/INPROC-2006-55.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we present a virtual memory system for sensor networks that uses flash-memory to extend the amount of RAM available on each node. By analyzing access traces from simulation tools it creates an efficient memory layout that makes virtual memory viable despite the resource constraints typical for sensor networks.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-55&engl=0}
}
@inproceedings {INPROC-2006-51,
   author = {Frank D{\"u}rr and Kurt Rothermel},
   title = {{An Overlay Network for Forwarding Symbolically Addressed Geocast Messages}},
   booktitle = {Proceedings of the 15th International Conference on Computer Communications and Networks (ICCCN '06); Arlington, VA, October 9-11, 2006},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {427--434},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2006},
   isbn = {0-4244-0572-6},
   keywords = {network protocols; communication protocols; geocast; location-based services},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-51/INPROC-2006-51.pdf,     http://dx.doi.org/10.1109/ICCCN.2006.286314},
   contact = {frank.duerr@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Geocast, which allows for forwarding messages to hosts residing at specified geographic areas, is a promising communication paradigm with a wide range of applications. Geocast target areas can be specified either by geometric figures or symbolic addresses, such as /usa/fl/miami/market-street. In this paper, we present a novel geocast routing protocol for symbolically addressed messages. Compared to geocast protocols based on geometric information, our protocol can operate on simple symbolic location models, and message forwarding does not require costly geometric operations. The proposed protocol is based on an overlay network that is mapped to an IP-based network infrastructure. The overlay network is structured in a hierarchical fashion, to ensure a scalable global geocast service supporting also large target areas. Although our protocol does not rely on a layer 3 multicast protocol, we also show how to improve the performance of message forwarding by integrating a light-weight layer 3 multicast protocol. Our evaluations of the protocol underline the scalability of our approach and show good routing quality leading to short message paths.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-51&engl=0}
}
@inproceedings {INPROC-2006-50,
   author = {Andreas Lachenmann and Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Matthias Gauger and Olga Saukh and Kurt Rothermel},
   title = {{TinyXXL: Language and Runtime Support for Cross-Layer Interactions}},
   booktitle = {Proceedings of the Third Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2006)},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {178--187},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2006},
   isbn = {1-4244-0626-9},
   keywords = {wireless sensor networks; cross-layer interactions; TinyXXL; data exchange; data sharing; parametrization},
   language = {Englisch},
   cr-category = {D.3.3 Programming Language Constructs and Features,     D.2.11 Software Engineering Software Architectures,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-50/INPROC-2006-50.pdf,     http://www.ipvs.uni-stuttgart.de/abteilungen/vs/forschung/projekte/tinycubus/start},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In the area of wireless sensor networks, cross-layer interactions are often preferred to strictly layered architectures. However, architectural properties such as modularity and the reusability of components suffer from such optimizations. In this paper we present TinyXXL that provides programming abstractions for data exchange, a form of cross-layer interaction with a large potential for optimizations. Our approach decouples components providing and using data, and it allows for automatic optimizations of applications composed of reusable components. Its runtime representation is efficient regarding memory consumption and processing overhead.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-50&engl=0}
}
@inproceedings {INPROC-2006-46,
   author = {Susanne B{\"u}rklen and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel and Timo Pfahl},
   title = {{Hoarding Location-Based Data Using Clustering}},
   booktitle = {Proceedings of the 4-th ACM International Workshop on Mobility Management and Wireless Access Protocols (MobiWAC 2006); Torremolinos, Spain, Oct. 2, 2006},
   publisher = {Sheridan Printing},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--1},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2006},
   language = {Englisch},
   cr-category = {H.3 Information Storage and Retrieval},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The proliferation of mobile devices and the fact that high-bandwidth and continuous connectivity is not available everywhere, has led to the creation of hoarding algorithms that attempt to mitigate the problems related with disconnected operation and with the operation in areas where bandwidth is either scarce or expensive. In this paper, we present a hoarding scheme for location-based data in semi-structured information spaces, such as the World Wide Web, which relies on clustering of semantically related data items. We show by means of experimental evaluation that our clustering-based approach outperforms existing hoarding techniques that do not make use of clustering by a factor of more than 2 in terms of hoard cache hit ratio.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-46&engl=0}
}
@inproceedings {INPROC-2006-43,
   author = {J{\"o}rg H{\"a}hner and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{Maintaining Update-Linearizability for Replicated Information in MANETs}},
   booktitle = {Proceedings of the First International Conference on Communication System Software and Middleware (COMSWARE 2006); New Delhi, India, January 2006},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2006},
   keywords = {update consistency; MANET; dissemination; replication},
   language = {Deutsch},
   cr-category = {H.2 Database Management,     C.2 Computer-Communication Networks,     E.1 Data Structures},
   contact = {joerg.haehner@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In the process of observing changes in our surroundings, the chronological ordering of these observations plays a crucial role. The same holds for many applications that employ sensors to gather information about their physical environment in order to adapt to changes. In this paper, we present a data replication algorithm for mobile ad hoc and sensor networks that guarantees chronological ordering of update operations for information objects. Information objects reflect the state of physical world objects and are updated by devices equipped with appropriate sensors. Our algorithm allows for multiple independent devices to update the same object and does not require synchronized clocks. We describe the underlying consistency model called update-linearizability and the design of the algorithm, and present simulations that show its feasibility in practice.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-43&engl=0}
}
@inproceedings {INPROC-2006-42,
   author = {Abdelmajid Khelil and Pedro Jos{\'e} Marr{\'o}n and Christian Becker and Kurt Rothermel},
   title = {{Hypergossiping: A Generalized Broadcast Strategy for MANETs}},
   booktitle = {Elsevier Ad Hoc Networks Journal},
   publisher = {Elsevier},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2006},
   keywords = {mobile ad hoc network (MANET); adaptive broadcast; network partitioning},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Broadcasting is a commonly used communication primitive needed by many applications and protocols in mobile ad hoc networks (MANET). Unfortunately, most broadcast solutions are tailored to one class of MANETs with respect to node density and node mobility and are unlikely to operate well in other classes. In this paper, we introduce hypergossiping, a novel adaptive broadcast algorithm that combines two strategies. Hypergossiping uses adaptive gossiping to efficiently distribute messages within single network partitions and implements an efficient heuristic to distribute them across partitions. Simulation results in ns-2 show that hypergossiping operates well for a broad range of MANETs with respect to node densities, mobility levels and network loads.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-42&engl=0}
}
@inproceedings {INPROC-2006-34,
   author = {Abdelmajid Khelil},
   title = {{Mobility-Aware Buffering for Delay-Tolerant Broadcasting in MANETs}},
   booktitle = {to appear in Proceedings of The International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS'06), Calgary, Canada, July, 2006},
   address = {Calgary, Canada},
   publisher = {n/a},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {0--1},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2006},
   keywords = {MANET, Delay-Tolerant Ad Hoc Networking, Broadcasting, Network Partitioning, Hypergossiping},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     I.6.5 Model Development},
   contact = {khelil.informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobility plays a major role in mobile ad hoc networks (MANETs), since it stresses networking tasks such as routing on the one hand, but aids to increase the network capacity and to overcome network partitioning on the other hand. To benefit from node mobility, a new class of MANET protocols and applications are designed to be delay-tolerant and mobility-aided. The main communication paradigm here is store-and-forward. For delay-tolerant mobility-aided networking, mobility on a large time-scale is a key feature. So far however, a few work is done to adapt store-and-forward concepts to the large time-scale mobility. Our first step that simplifies the adaptation to node mobility, is a set of novel mobility metrics. These metrics quantify the mobility on a large time-scale and are based on the pair-wise contacts between mobile nodes. In this paper, we show how to exploit these mobility metrics to design an efficient buffering strategy for hypergossiping, a delay-tolerant mobility-aided MANET broadcasting protocol. The novel buffering strategy detects relevant mobility patterns at run-time, using contact-based mobility metrics, and adapts the buffering decision to the detected mobility pattern.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-34&engl=0}
}
@inproceedings {INPROC-2006-29,
   author = {Illya Stepanov and Kurt Rothermel},
   title = {{Simulating Mobile Ad-Hoc Networks in City Scenarios}},
   booktitle = {Proceedings of the 4th International Conference on Wired/Wireless Internet Communications (WWIC 2006), Bern, Switzerland, May 2006},
   editor = {T. Braun and G. Carle and S. Fahmy and Y. Koucheryavy (Eds.)},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--12},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2006},
   isbn = {3-540-34023-8},
   keywords = {Communication systems; mobile communication; modeling; simulation},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.4 Performance of Systems,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-29/INPROC-2006-29.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Simulation tools are frequently used for performance evaluations of mobile ad-hoc networks. Currently the tools poorly support urban scenarios, since they do not take a spatial environment into account. In this paper, we describe a platform for the modeling of city scenarios. We extend ns-2 with corresponding mobility and wireless transmission models. By using its emulation facility, we integrate unmodified applications and real implementations of network protocols. We demonstrate the usefulness of the platform for performance evaluations by modeling a mobile application in a simulated environment of Stuttgart downtown. We show that it helps identifying application problems before deployment.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-29&engl=0}
}
@inproceedings {INPROC-2006-27,
   author = {Florian Bitzer and Dominique Dudkowski and Norbert Haala},
   title = {{Investigation of Empirical Pedestrian Traces for Calibrating Microscopic Mobility Models}},
   booktitle = {Proceedings of the International Symposium Networks for Mobility 2006, Stuttgart, Germany},
   editor = {Wolfgang M{\"o}hlenbrink and Frank Englmann and Markus Friedrich and Ullrich Martin and Ulrich Hangleiter},
   address = {Stuttgart},
   publisher = {Eigenverlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2006},
   keywords = {pedestrian; microscopic; simulation; empirical data},
   language = {Deutsch},
   cr-category = {I.6.0 Simulation and Modeling General},
   contact = {florian.bitzer@isv.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Photogrammetrie (ifp);     Universit{\"a}t Stuttgart, Institut f{\"u}r Stra{\ss}en- und Verkehrswesen, Abteilung Stra{\ss}enplanung und Stra{\ss}enbau (ISV/SuS)},
   abstract = {In the research field of microscopic simulation models for pedestrian mobility substantial pro-gress was achieved in recent years. The ongoing strong growth of computational power to-gether with new approaches founding on cellular automata allows the microscopic simulation of large-scale scenarios like the evacuation of whole soccer stadiums, as self-organization can be initiated by using a relatively simple rule set. Recent developments at the Institute for Road and Transportation Science will now ease the simulation of everyday situations with multiple source-destination relations as they occur e.g. in city centers, airport terminals and public transport interchange points. Regardless of its level of detail, each mobility simulation model is in need of comprehensive empirical data for validation and calibration purposes. Thereby macroscopic mobility models, e.g. traffic assignment models, only need cross sectional data like “vehicles per time seg-ment” for instance. Concerning pedestrian mobility on the large scale, only macroscopic sur-veys like cordon counting in a public transport system or traveler flow counting in an airport terminal have been carried out up to now. However, the empirical data resulting from these surveys is not suitable for calibrating and validating microscopic simulation models for pedes-trian traffic, because they only deliver aggregated traffic flow data. Therefore it was neces-sary to develop a new survey method which allows the noninvasive recording and analysis of pedestrian traces. In collaboration with the Institute of Transport Research of the German Aerospace Center (DLR) a two-day video survey at the Campus Vaihingen of Universit{\"a}t Stuttgart was carried out. By a network of four wide-angle cameras placed at strategic viewpoints, a central area of the campus of about 20,000 sqm incorporating the commuter railway station and the sur-rounding buildings was recorded at a rate of five frames per second with a spatial resolution of 1024x786 pixels of each camera. In order to analyze the collected imagery of some giga-bytes of raw data, solutions for several challenges had to be found. First, suitable tie and control points for georeferencing of the respective cameras had to be identified. This is re-quired to transform the pedestrians’ trajectories from the respective images to a common reference system. Second, methods for deriving pedestrian trajectories from consecutive frames as well as the distinction between pedestrians’ movements and the movement of all other objects had to be improved. Third, unique tags had to be assigned to the observed pe-destrians to trace them over the whole monitored area while they are tracked by the different cameras. The resulting new and unique data set not only consists of pedestrian traces with decided timestamps at each waypoint, it also includes the resulting source-destination matrix on which the timestamp for each pedestrian allows many kinds of statistical operations, e.g. the computation of the average walking time and standard deviation on different source-destination relations. The availability of these real traces will finally enable extensive and high-quality calibration and validation operations for microscopic simulation models. The dataset may even serve as input information for simulation in the research field of communi-cation networks, in particular, in mobile ad hoc networks. In the near future, the detailed ex-amination of many other problems, such as counter flow, crossing behavior, and path build-ing phenomena based on real microscopic mobility data will become possible.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-27&engl=0}
}
@inproceedings {INPROC-2006-25,
   author = {Susanne B{\"u}rklen and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{Proactive Hoarding in Location-Based Systems}},
   booktitle = {Proceedings of the Second Workshop on Context Awareness for Proactive Systems (CAPS 2006)},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--11},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2006},
   keywords = {Hoarding; location-based systems},
   language = {Englisch},
   cr-category = {H.3 Information Storage and Retrieval},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The proliferation of mobile devices and the fact that high-bandwidth connectivity is not available everywhere, has led to the development of hoarding algorithms. The aim of these algorithms is to select and prefetch data, mobile users might access when they are weakly connected in the future. The data is selected based on context information of users, such as their location. In this paper, we present a hoarding approach for semi-structured information items and introduce our Bounded Path Search algorithm (BPS) for the computation of the hoard list. We show by means of experimental evaluation that BPS outperforms existing hoarding techniques that use standard graph search algorithms by a factor of 2.7 in terms of hoard cache hit ratio.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-25&engl=0}
}
@inproceedings {INPROC-2006-13,
   author = {Tobias Drosdol and Dominique Dudkowski and Christian Becker and Kurt Rothermel},
   title = {{Efficient Indexing of Symbolic Location Information}},
   booktitle = {Proceedings of the Second Workshop on Context Awareness for Proactive Systems (CAPS 2006)},
   address = {Kassel, Germany},
   publisher = {---},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2006},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     E.2 Data Storage Representations,     H.3 Information Storage and Retrieval},
   contact = {Tobias.Drosdol@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Providing context-awareness in future applications demands for accurate information about the positions of a potentially large number of mobile objects. This requires location management systems that are capable of coping with a huge amount of such highly dynamic data. To efficiently retrieve relevant information, e.g., all objects located inside a given area, these systems must utilize adequate index structures. In the past, suitable indexes have been explored for geometric representations of location information only. The contribution of this paper is a generic index structure for the efficient management of symbolic location information. Based on different index variants an adaptive approach is derived that can be adjusted to accommodate different ratios of update and retrieval load. Our experimental results show how this can significantly increase the overall performance of a location management system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-13&engl=0}
}
@inproceedings {INPROC-2006-08,
   author = {Torben Weis and Marcus Handte and Mirko Knoll and Christian Becker},
   title = {{Customizable Pervasive Applications}},
   booktitle = {Proceedings of 4th IEEE International Conference on Pervasive Computing and Communications},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--6},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2006},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks,     D.2 Software Engineering,     D.3 Programming Languages},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Human behavior and housing resist every stan-dardization effort. Many aspects such as different technical equipment, furniture, and usage patterns make our surroundings as individual as ourselves. Thus, the personalization of pervasive applications is a fundamental requirement. To enable the development of custom pervasive applications, we propose a soft-ware development process. This process is based on the successful process for modern desktop applica-tions. There, developers create extensible applications and components. Customizers use the resulting arti-facts to develop custom applications. Finally, users configure applications to their individual needs by adjusting predefined settings. To adopt this process for Pervasive Computing, we present a component system for developers, a graphical toolkit for customizers, and self-configuration algorithms to ease the deployment.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-08&engl=0}
}
@inproceedings {INPROC-2006-06,
   author = {Matthias Wieland and Frank Leymann and Lamine Jendoubi and Daniela Nicklas and Frank D{\"u}rr},
   title = {{Task-orientierte Anwendungen in einer Smart Factory}},
   booktitle = {Mobile Informationssysteme - Potentiale, Hindernisse, Einsatz. Proceedings MMS´06},
   editor = {Thomas Kirste and Birgitta K{\"o}nig-Ries and Key Pousttchi and Klaus Turowski},
   address = {Bonn},
   publisher = {Gesellschaft f{\"u}r Informatik},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Lecture Notes in Informatics (LNI)},
   volume = {P-76},
   pages = {139--143},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2006},
   isbn = {3-88579-170-6},
   keywords = {Kontextbezogene Applikationen; Smart Factory; kontextbezogene Workflows},
   language = {Deutsch},
   cr-category = {H.4.2 Information Systems Applications Types of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-06/INPROC-2006-06.pdf,     http://www.nexus.uni-stuttgart.de/},
   contact = {Matthias Wieland wieland@informatik.uni-stuttgart.de, Daniela Nicklas nicklas@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Industrielle Fertigung und Fabrikbetrieb (IFF);     Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In diesem Beitrag wird aufgezeigt, welche M{\"o}glichkeiten sich durch den Einsatz task-orientierter, explorativer Anwendungen im Umfeld einer Smart Factory ergeben. Nach einer kurzen Charakterisierung dieser Anwendungsklasse wird ein Szenario geschildert, das Wartungsaufgaben in einer Fabrik mit diesen Konzepten l{\"o}st. Daraus ergibt sich die Vision einer Smart Factory, in der die Gesch{\"a}ftsprozesse {\"u}ber ein Kontextmodell mit den technischen Prozessen der Produktionsstra{\ss}e gekoppelt werden.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-06&engl=0}
}
@inproceedings {INPROC-2006-05,
   author = {Dominique Dudkowski and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{An Efficient Resilience Mechanism for Data Centric Storage in Mobile Ad Hoc Networks}},
   booktitle = {Proceedings of the 7th International Conference on Mobile Data Management (MDM '06); Nara, Japan, May 2006.},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2006},
   keywords = {Mobile Ad Hoc Networks; mobile Ad-hoc-Netze; Data Centric Storage; DCS; datenzentrische Speicherung; infrastrukturlose Systeme; MANETs; MANET},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-05/INPROC-2006-05.pdf},
   contact = {dominique.dudkowski@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Data Centric Storage (DCS) is a powerful storage paradigm for wireless ad hoc networks. In mobile ad hoc networks (MANETs), however, the mobility and varying density of nodes may significantly impact the efficiency of data access and the level of data consistency for existing DCS mechanisms. In this paper, we propose an efficient resilience mechanism for data centric storage that supports DCS in mobile environments. We introduce a novel indirection strategy that enables us to distinguish the storage of data at dedicated server nodes from the storage of additional information to locate these servers. Our approach places server location information dynamically in strategic parts of the network based on its current topology. Combining our server location advertisement with any geographic routing protocol, we provide a robust data update and query processing technique for data centric storage in MANETs. We show analytically and by means of experimental evaluations that, despite the additional indirection during packet forwarding, our approach provides superior storage and retrieval performance than the original DCS algorithm even for large amounts of dynamic data.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-05&engl=0}
}
@inproceedings {INPROC-2006-04,
   author = {Dominique Dudkowski and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{Efficient Algorithms for Probabilistic Spatial Queries in Mobile Ad Hoc Networks.}},
   booktitle = {Proceedings of the First International Conference on Communication System Software and Middleware (COMSWARE 2006); New Delhi, India, January 2006.},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2006},
   keywords = {Mobile Ad Hoc Networks; Mobile Ad-hoc-Netze; infrastrukturlose Systeme; probabilistische Anfragen; r{\"a}umliche Anfragen; spatial queries; probabilistic queries; Anfrageverarbeitung; query processing; data management; MANET},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-04/INPROC-2006-04.pdf},
   contact = {dominique.dudkowski@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the proliferation of wireless communication and sensor technology, the importance of location-based applications has tremendously increased. In order to support these applications, services that implement algorithms for the efficient processing of spatial queries, such as range and k-nearest neighbor queries, are definitely beneficial. In this paper, we propose definitions of probabilistic range and k-nearest neighbor query semantics that take into account the inaccurate position information acquired from positioning systems. We introduce efficient algorithms for distributed storage of the dynamic information captured by positioning sensors on mobile network nodes, and for processing the aforementioned queries in mobile ad hoc networks. We show by evaluation that the studied algorithms incur small communication costs, and that the query algorithms return accurate results in a timely manner.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-04&engl=0}
}
@inproceedings {INPROC-2006-02,
   author = {Olga Saukh and Pedro Jos{\'e} Marr{\'o}n and Andreas Lachenmann and Matthias Gauger and Daniel Minder and Kurt Rothermel},
   title = {{Generic Routing Metric and Policies for WSNs}},
   booktitle = {Wireless Sensor Networks: Third European Workshop, EWSN 2006, Zurich, Switzerland, February 13-15, 2006. Proceedings},
   editor = {Kay R{\"o}mer and Holger Karl and Friedemann Mattern},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {3868},
   pages = {99--114},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2006},
   isbn = {3-540-32158-6},
   keywords = {Wireless Sensor Network},
   language = {Englisch},
   cr-category = {C.3 Special-Purpose and Application-Based Systems,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-02/INPROC-2006-02.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Energy-aware algorithms have proven to be a crucial part of sensor network applications, especially if they are required to operate for extended periods of time. Among these, efficient routing algorithms are of utter importance since their effect can be experienced by all other layers. Thus, the optimization and accurate prediction of the lifetime of the system can only be performed in the presence of accurate execution models that take energy consumption into account. In this paper, we propose a generic routing metric and associated policies that encompass most other existing metrics in the literature and use this model for the optimal construction of a routing tree to the sink. We also provide experimental results that show the benefits of using our novel metric.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-02&engl=0}
}
@inproceedings {INPROC-2006-01,
   author = {Pedro Jos{\'e} Marr{\'o}n and Matthias Gauger and Andreas Lachenmann and Daniel Minder and Olga Saukh and Kurt Rothermel},
   title = {{FlexCup: A Flexible and Efficient Code Update Mechanism for Sensor Networks}},
   booktitle = {Wireless Sensor Networks: Third European Workshop, EWSN 2006, Zurich, Switzerland, February 13-15, 2006. Proceedings},
   editor = {Kay R{\"o}mer and Holger Karl and Friedemann Mattern},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {3868},
   pages = {212--227},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2006},
   isbn = {3-540-32158-6},
   language = {Englisch},
   cr-category = {C.3 Special-Purpose and Application-Based Systems,     D.3.4 Programming Languages Processors,     D.4.9 Systems Programs and Utilities},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-01/INPROC-2006-01.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The ability to update the program code installed on wireless sensor nodes plays an import role in the highly dynamic environments sensor networks are often deployed in. Such ode update mechanisms should support flexible reconfiguration and adaptation of the sensor nodes but should also operate in an energy and time efficient manner. In this paper, we present FlexCup, a flexible code update mechanism that minimizes the energy consumed on each sensor node for the installation of arbitrary code changes. We describe two different versions of FlexCup and show, using a precise hardware emulator, that our mechanism is able to perform updates up to 8 times faster than related code update algorithms found in the literature, while consuming only an eighth of the energy.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-01&engl=0}
}
@inproceedings {INPROC-2005-98,
   author = {Abdelmajid Khelil and Jos{\'e} Pedro Marr{\'o}n and Kurt Rothermel},
   title = {{Contact-Based Mobility Metrics for Delay-Tolerant Ad Hoc Networking}},
   booktitle = {Proceedings of the 13th IEEE International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems: MASCOTS'05; Atlanta, Georgia, September, 2005},
   address = {Los Alamitos, California},
   publisher = {IEEE Conference Publishing Services},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {IEEE Computer Society Order Number},
   volume = {P2458},
   pages = {435--444},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2005},
   isbn = {0-7695-2458-3},
   keywords = {MANET; Contact; encounter; delay-tolerant; mobility metrics},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     I.6.5 Model Development},
   contact = {Universit{\"a}t Stuttgart / IPVS, Universit{\"a}tsstr. 38 70569 Stuttgart, Germany, {khelil, marron, rothermel}@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobility plays a major role in mobile ad hoc networks (MANETs) since it stresses networking tasks such as routing on one hand but aids to increase the network capacity and to overcome network partitioning on the other hand. To benefit from node mobility, a new class of MANET protocols and applications are designed to be delay-tolerant and mobility-aided. For delay-tolerant mobility-aided networking mobility on a large time-scale is a key feature. So far, in MANETs, the mobility is investigated on a short time-scale. That is why we present novel mobility metrics that quantify a large time-scale mobility. Our approach is based on the pair-wise contacts between mobile nodes. We present a detailed statistical study of our novel metrics using the widely used random waypoint mobility model as an example. For the random waypoint model we introduce an analytical model, which allows protocol developers to analytically compute some of the designed metrics. In order to provide an easy access to these metrics in a network simulator, we provide a framework for ns-2.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-98&engl=0}
}
@inproceedings {INPROC-2005-97,
   author = {Abdelmajid Khelil and Jos{\'e} Pedro Marr{\'o}n and R{\"u}diger Dietrich and Kurt Rothermel},
   title = {{Evaluation of Partition-Aware MANET Protocols and Applications with ns-2}},
   booktitle = {Proceedings of the 2005 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS ’05), Philadelphia, PA, July 24–28, 2005},
   address = {Cherry Hill, NJ, USA},
   publisher = {Simulation Councils, Inc.},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {SIM Series},
   volume = {37(3)},
   pages = {435--444},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2005},
   isbn = {1-56555-300-4},
   keywords = {MANET; Network Partitioning; Protocol Evaluation; ns-2; Hypergossiping},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   contact = {Universit{\"a}t Stuttgart / IPVS, Universit{\"a}tsstr. 38 70569 Stuttgart, Germany, {khelil, marron, rothermel}@informatik.uni-stuttgart.de, ruediger.dietrich@gmx.net},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobile Ad Hoc Networks (MANET) are composed of mobile devices equipped with short range radio capabilities. Commu­nication is possible between devices located in each other's transmission range. Especially in sparse MANETs, node mo­bility leads to frequent network partitioning, which makes typical networking tasks much more difficult. Although we observe an increasing need for partitioning information, the widely used network simulator ns­2 does not support proto­col developers to easily evaluate their protocols concerning network partitioning. To simplify the evaluation of MANET partition­aware pro­tocols and applications in ns­2, we extend the simulator to provide partitioning information at the simulation time. De­velopers might be interested in using this information to eval­uate their partition­aware protocols and applications and to compare their performance to the optimal case. Hypergossiping is a partition­aware broadcast protocol for MANETs. Nodes rebroadcast messages upon joining the par­titions that have not yet received these messages. Hypergos­siping uses a heuristic to detect partition joins. We show the feasibility of our approach and the applicability of the parti­tioning information we provide for ns­2 users to compare the performance of our approach to the optimal case.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-97&engl=0}
}
@inproceedings {INPROC-2005-96,
   author = {Abdelmajid Khelil and Jos{\'e} Pedro Marr{\'o}n and Christian Becker and Kurt Rothermel},
   title = {{Hypergossiping: A Generalized Broadcast Strategy for Mobile Ad Hoc Networks}},
   booktitle = {Proceedings of Kommunikation in Verteilten Systemen 2005 (KiVS'05); Kaiserslautern, Germany, 2005},
   address = {Kaiserslautern},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {0--1},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2005},
   keywords = {mobile ad hoc network (MANET); adaptive broadcast; network partitioning},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   contact = {Universit{\"a}t Stuttgart / IPVS / VS Universit{\"a}tsstrasse 38, 70569 Stuttgart, Germany +49 711 7816 {251, 357, 228, 434} {khelil, marron, becker, rothermel}@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Broadcasting is a commonly used communication primitive needed by many applications and protocols in mobile ad hoc networks (MANETs). Unfortunately, most broadcast solutions are tailored to one class of MANETs with respect to node density and node mobility and are unlikely to operate well in other classes. In this paper, we introduce hypergossiping, a novel adaptive broadcast algorithm that combines two strategies. Hypergossiping uses adaptive gossiping to efficiently distribute messages within single network partitions and implements an efficient heuristic to distribute them across partitions. Simulation results in ns-2 show that hypergossiping operates well for a broad range of MANETs with respect to node densities and mobility levels.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-96&engl=0}
}
@inproceedings {INPROC-2005-85,
   author = {Arno Wacker and Mirko Knoll and Timo Heiber and Kurt Rothermel},
   title = {{A New Approach for Establishing Pairwise Keys for Securing Wireless Sensor Networks}},
   booktitle = {Proceedings of the Third International Conference on Embedded Networked Sensor Systems: ACM SenSys'05; San Diego, California, November 2-4, 2005},
   address = {San Diego},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {27--38},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2005},
   isbn = {1-59593-054-X},
   keywords = {Wireless Sensor Network Security, Key Establishment},
   language = {Englisch},
   cr-category = {D.4.6 Operating Systems Security and Protection,     C.2.0 Computer-Communication Networks, General,     C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-85/INPROC-2005-85.pdf},
   contact = {Senden sie eine mail an arno.wacker@ipvs.uni-stuttgart.de oder arno@wacker-online.net},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Wireless sensor networks based on highly resource-constrained devices require symmetric cryptography in order to make them secure. Integral to this is the exchange of unique symmetric keys between two devices. In this paper, we propose a novel decentralized key exchange protocol that guarantees the confidentiality of a key exchange even if an attacker has compromised some of the devices in the network. A central objective of the protocol design was to minimize resource consumption on the individual devices. We evaluate the resource requirements of our protocol in terms of memory requirements, CPU usage and network traffic both through theoretical analysis and through simulations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-85&engl=0}
}
@inproceedings {INPROC-2005-73,
   author = {Marcus Handte and Christian Becker and Kurt Rothermel},
   title = {{Peer-based Automatic Configuration of Pervasive Applications}},
   booktitle = {Proceedings of the 2nd IEEE International Conference on Pervasive Services (ICPS 2005), Santorini, Greece, 11-14 July,2005},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {249--260},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2005},
   language = {Deutsch},
   cr-category = {D.2.7 Software Engineering Distribution, Maintenance, and Enhancement},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive computing envisions seamless support for user tasks through cooperating devices that are present in an environment. Fluctuating availability of devices, induced by mobility and failures, requires mechanisms and algorithms that allow applications to adapt to changing environmental conditions without user intervention. To ease the development of adaptive applications, we have proposed the peer-based component system PCOM. This system provides fundamental mechanisms to support the automated composition of applications at runtime. In this paper, we discuss the requirements on peer-based automatic configuration of pervasive applications and present an approach based on distributed constraint satisfaction. The resulting algorithm configures applications in the presence of strictly limited resources. To show the feasibility of the approach, we have integrated the algorithm into PCOM and provide an evaluation based on simulation and measurements.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-73&engl=0}
}
@inproceedings {INPROC-2005-72,
   author = {Marcus Handte and Gregor Schiele and Stephan Urbanski and Christian Becker},
   title = {{Adaptation Support for Stateful Components in PCOM}},
   booktitle = {Workshop on Software Architectures for Self-Organization: Beyond Ad-Hoc Networking at Pervasive 2005, M{\"u}nchen, Germany, 2005},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--5},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2005},
   keywords = {Adaptation, Stateful Services},
   language = {Deutsch},
   cr-category = {D.2.7 Software Engineering Distribution, Maintenance, and Enhancement},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In ever-changing environments as they are envisioned in Pervasive Computing, applications have to adapt to changes in their execution environment. Reselection of services is a common technique for stateless services. This paper presents an approach that allows reselection of stateful services by combining checkpointing techniques and client-side request histories. An implementation that allows transparent service reselection is outlined and parameters for the automatic creation of checkpoints are discussed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-72&engl=0}
}
@inproceedings {INPROC-2005-71,
   author = {Pedro Jos{\'e} Marr{\'o}n and Matthias Gauger and Andreas Lachenmann and Daniel Minder and Olga Saukh and Kurt Rothermel},
   title = {{Adaptive System Software Support for Cooperating Objects}},
   booktitle = {Proceedings of the Workshop on Smart Object Systems; Tokyo, Japan},
   publisher = {N/A},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2005},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     D.4.7 Operating Systems Organization and Design},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-71/INPROC-2005-71.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Efficient system software support is essential for cooperating object applications in order to cope with the complexity and heterogeneity of typical scenarios in this domain. In this paper, we argue that adaptation capabilities should be an integral part of such system software and present the TinyCubus framework as one possible solution that provides the features required of system software for cooperating objects.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-71&engl=0}
}
@inproceedings {INPROC-2005-70,
   author = {Daniel Minder and Pedro Jos{\'e} Marr{\'o}n and Andreas Lachenmann and Kurt Rothermel},
   title = {{Experimental construction of a meeting model for smart office environments}},
   booktitle = {Proceedings of the First REALWSN 2005 Workshop on Real-World Wireless Sensor Networks, SICS Technical Report T2005:09},
   publisher = {N/A},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2005},
   keywords = {Wireless Sensor Network},
   language = {Englisch},
   cr-category = {C.3 Special-Purpose and Application-Based Systems,     I.6.5 Model Development},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-70/INPROC-2005-70.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The simulation of mobile networks requires mobility models that reproduce the movement of nodes in a realistic way. Although many such models exist, they are not well suited for model office scenarios in which movements are mostly caused by people meeting in known locations to discuss some issues. We present first steps towards a meeting model for office environments which is based on the real world movement data gathered after performing a one-week sensor network deployment in our department. We describe details about the processing of the acquired data, the construction, and the execution of the movement model. Finally, we discuss some of the lessons learned throughout the experiment.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-70&engl=0}
}
@inproceedings {INPROC-2005-69,
   author = {Andreas Lachenmann and Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Kurt Rothermel},
   title = {{An Analysis of Cross-Layer Interactions in Sensor Network Applications}},
   booktitle = {Proceedings of the 2005 Intelligent Sensors, Sensor Networks \& Information Processing Conference},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {121--126},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2005},
   isbn = {0-7803-9400-3},
   keywords = {wireless sensor networks; cross-layer interactions; data sharing; TinyXXL},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     D.2.11 Software Engineering Software Architectures,     D.3.3 Programming Language Constructs and Features},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-69/INPROC-2005-69.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In the field of sensor networks cross-layer interactions are favored over strict layering of components and regarded as a way to provide the optimization capabilities required by sensor network applications. Despite their importance, developers tend to devise specific solutions for the application at hand, instead of designing more general primitives that can be used across applications. The contribution of this paper is twofold: We analyze several typical sensor network applications and provide a classification of the types of cross-layer interactions found in their code. Based on this classification, we propose TinyXXL, an extension to the nesC language that defines primitives for seamless cross-layer data exchange.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-69&engl=0}
}
@inproceedings {INPROC-2005-68,
   author = {Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Andreas Lachenmann and Olga Saukh and Kurt Rothermel},
   title = {{Generic Model and Architecture for Cooperating Objects in Sensor Network Environments}},
   booktitle = {Proceedings of the 12th International Conference on Telecommunications (ICT 2005)},
   publisher = {N/A},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2005},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-68/INPROC-2005-68.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The complexity and heterogeneity of cooperating object applications in ubiquitous environments or of applications in the sensor network domain require the use of generic models and architectures. These architectures should provide support for the following three key issues: flexible installation, management and reconfiguration of components in the system; optimization strategies whose implementation usually involves the proper management of cross-layer information; and proper adaptation techniques that allow for the self-configuration of nodes and components in the system with minimal human intervention. In this paper, we present one possible instance of such a generic model and architecture and show its applicability using Sustainable Bridges, a sensor network application that requires the analysis of complex sensor data to achieve its goal of effectively monitoring bridges for the detection of structural defects.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-68&engl=0}
}
@inproceedings {INPROC-2005-67,
   author = {Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Andreas Lachenmann and Kurt Rothermel},
   title = {{TinyCubus: A Flexible and Adaptive Cross-Layer Framework for Sensor Networks}},
   booktitle = {4. GI/ITG KuVS Fachgespr{\"a}ch ``Drahtlose Sensornetze'', Technical Report TR 481, Computer Science Department, ETH Zurich},
   publisher = {N/A},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {49--54},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2005},
   language = {Deutsch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-67/INPROC-2005-67.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the proliferation of sensor networks and sensor network applications during the last few years, the overall complexity of such systems is continuously increasing. Sensor networks are now heterogeneous in terms of their hardware characteristics and application requirements even within a single network. In addition, the requirements of current applications are expected to change over time. All of this makes developing, deploying, and optimizing sensor network applications an extremely difficult task. In the TinyCubus project we research a necessary infrastructure to support the complexity of such systems. TinyCubus consists of a data management framework, a cross-layer frame work, and a configuration engine. The data management framework allows the dynamic selection and adaptation of system and data management components. The cross-layer framework supports data sharing and other forms of interaction between components in order to achieve cross-layer optimizations. The configuration engine allows code to be distributed reliably and efficiently by taking into account the topology of sensors and their assigned functionality.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-67&engl=0}
}
@inproceedings {INPROC-2005-58,
   author = {Daniela Nicklas and Susanne B{\"u}rklen and Tobias Drosdol and Nicola H{\"o}nle},
   title = {{Benefits of Context Models in Smart Environments}},
   booktitle = {2. GI/ITG KuVS Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste},
   editor = {J{\"o}rg Roth},
   address = {Hagen},
   publisher = {Fernuniversit{\"a}t Hagen},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Informatik Bericht},
   volume = {324},
   pages = {12--15},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2005},
   keywords = {context models; smart environment; smart room; Nexus},
   language = {Englisch},
   cr-category = {H.4 Information Systems Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-58/INPROC-2005-58.pdf,     http://dreamteam.fernuni-hagen.de/fg_lbs/meeting_2/meeting_2.html,     http://www.nexus.uni-stuttgart.de},
   contact = {daniela.nicklas@informatik.uni-stuttgart.de susanne.buerklen@informatik.uni-stuttgart.de tobias.drosdol@informatik.uni-stuttgart.de nicola.hoenle@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Ongoing technologic advances drive the emergence of smart items, everyday objects with embedded microcomputers and communication capabilities. In a smart envi-ronment a multitude of such smart items exist to assist its users. In this paper, we will show how smart environments can benefit from the concepts of the Nexus platform, an open pervasive computing system that supports various kinds of context-aware applica-tions by providing a federated, potentially global context model.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-58&engl=0}
}
@inproceedings {INPROC-2005-37,
   author = {Illya Stepanov and Daniel Herrscher and Kurt Rothermel},
   title = {{On the Impact of Radio Propagation Models on MANET Simulation Results}},
   booktitle = {Proceedings of the 7th IFIP International Conference on Mobile and Wireless Communication Networks (MWCN 2005), Marrakech, Morocco, September 2005},
   publisher = {N/A},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2005},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.4 Performance of Systems,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-37/INPROC-2005-37.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Network simulation tools are frequently used to analyze performance of MANET protocols and applications. They commonly offer only simple radio propagation models that neglect obstacles of a propagation environment. In this paper, we integrate a more accurate radio propagation model into a simulation tool. The model is based on ray tracing and considers geographic data of the simulation area. We prove that the usage of a more precise propagation model changes simulated connection topologies considerably. Consequently, we obtain different performance evaluation results. To our best knowledge, no other study of MANETs has been performed so far with such a detailed radio propagation model. Hence, this paper also gives new insights on the realistic performance of MANETs in outdoor environments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-37&engl=0}
}
@inproceedings {INPROC-2005-31,
   author = {Frank D{\"u}rr and Christian Becker and Kurt Rothermel},
   title = {{Efficient Forwarding of Symbolically Addressed Geocast Messages}},
   booktitle = {Proceedings of the 14th International Conference on Computer Communications an Networks (ICCCN 2005); San Diego, CA, October 2005},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {77--85},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2005},
   doi = {10.1109/ICCCN.2005.1523812},
   keywords = {Geocast, Multicast, Networking, Communication Network, Location-based Service},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-31/INPROC-2005-31.pdf,     http://dx.doi.org/10.1109/ICCCN.2005.1523812},
   contact = {frank.duerr@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Geocast is used to send messages to all hosts located in a geographic area. This target area can be defined either by geometric figures like polygons or by symbolic addresses like city names or room numbers. Geographic routing algorithms, which forward messages based on geographic information, can be used to forward geocast messages. If routing of symbolically addressed messages is based on geometric coordinates, complex mappings between symbolic addresses and their geometric extent as well as complex geometric operations are required. Therefore, we propose a routing algorithm for symbolically addressed geocast messages that operates directly on a symbolic location model. This approach does not require any geometric information for message forwarding, and forwarding decisions can be realized efficiently by comparably simple operations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-31&engl=0}
}
@inproceedings {INPROC-2005-26,
   author = {Steffen Maier and Daniel Herrscher and Kurt Rothermel},
   title = {{On Node Virtualization for Scalable Network Emulation}},
   booktitle = {Proceedings of the 2005 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS ’05), Philadelphia, PA, July 24–28, 2005},
   publisher = {Simulation Councils, Inc.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {917--928},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2005},
   keywords = {software performance evaluation; network emulation; mobile ad hoc networks; scalability; virtual routing},
   language = {Englisch},
   cr-category = {C.4 Performance of Systems,     D.4.4 Operating Systems Communications Management,     D.4.8 Operating Systems Performance,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-26/INPROC-2005-26.pdf,     http://net.informatik.uni-stuttgart.de/},
   contact = {e-mail to Steffen Maier maier@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {During the development of network protocols and distributed applications, their performance has to be analyzed in appropriate environments. Network emulation testbeds provide a synthetic, configurable network environment for comparative performance measurements of real implementations. Realistic scenarios have to consider hundreds of communicating nodes. Common network emulation approaches limit the number of nodes in a scenario to the number of computers in an emulation testbed. To overcome this limitation, we introduce a virtual node concept for network emulation. The key problem for node virtualization is a transparent, yet efficient separation of node resources. In this paper, we provide a brief survey of candidate node virtualization approaches to facilitate scalable network emulation. Based on the gathered insights, we propose a lightweight virtualization solution to achieve maximum scalability and discuss the main points regarding its implementation. We present extensive evaluations that show the scalability and transparency of our approach in both a traditional wired infrastructure-based, and in a wireless ad hoc network emulation scenario. The measurements indicate that our solution can push the upper limit of emulation scenario sizes by a factor of 20 to 30. Given our emulation testbed consisting of 64 computers, this translates to possible scenario sizes of up to 1920 nodes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-26&engl=0}
}
@inproceedings {INPROC-2005-21,
   author = {Martin Bauer and Kurt Rothermel},
   title = {{An Architecture for Observing PhysicalWorld Events}},
   booktitle = {Proceedings of the 11th International Conference on Parallel and Distributed Systems: ICPADS 2005; Fukuoka, Japan, July 20-22, 2005},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2005},
   keywords = {distributed systems; event service; event service architecture; event observation; real-world events; world model; distributed world model},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.3 Information Search and Retrieval,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://www.nexus.uni-stuttgart.de},
   contact = {Martin Bauer mabauer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we investigate the observation of physical world events, i.e. events that occur in the physical world, and are observed through model data, part of which is collected by sensors. The physical world events of interest here are those that are suitable for proactively supporting mobile users. This means that they have to be on the same highabstraction level as perceived by the user. In a large-scale system as we envision it, the model data needed for the observation of these high-level physical world events may be distributed over multiple servers. We first present a requirement analysis. Then we propose an event service architecture that fulfills the requirements. Finally, we show the scalability of the approach through an evaluation based on a prototype implementation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-21&engl=0}
}
@inproceedings {INPROC-2005-15,
   author = {Pedro Jos{\'e} Marr{\'o}n and Andreas Lachenmann and Daniel Minder and J{\"o}rg H{\"a}hner and Robert Sauter and Kurt Rothermel},
   title = {{TinyCubus: A Flexible and Adaptive Framework for Sensor Networks}},
   booktitle = {Proceedings of the Second European Workshop on Wireless Sensor Networks (EWSN 2005)},
   editor = {Erdal Cayirci and Sebnem Baydere and Paul Havinga},
   address = {Istanbul, Turkey},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {278--289},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2005},
   isbn = {0-7803-8801-1},
   keywords = {sensor network; system architecture; adaptation; framework; code distribution; cross-layer},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     D.4.7 Operating Systems Organization and Design},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-15/INPROC-2005-15.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the proliferation of sensor networks and sensor network applications, the overall complexity of such systems is continuously increasing. Sensor networks are now heterogeneous in terms of their hardware characteristics and application requirements even within a single network. In addition, the requirements of currently supported applications are expected to change over time. All of this makes developing, deploying, and optimizing sensor network applications an extremely difficult task. In this paper, we present the architecture of TinyCubus, a flexible and adaptive cross-layer framework for TinyOS based sensor networks that aims at providing the necessary infrastructure to cope with the complexity of such systems. TinyCubus consists of a data management framework that selects and adapts both system and data management components, a cross-layer framework that enables optimizations through cross-layer interactions, and a configuration engine that installs components dynamically. Furthermore, we show the feasibility of our architecture by describing and evaluating a code distribution algorithm that uses application knowledge about the sensor topology in order to optimize its behavior.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-15&engl=0}
}
@inproceedings {INPROC-2005-14,
   author = {Dominique Dudkowski and Tobias Drosdol and Pedro Jos{\'e} Marr{\'o}n},
   title = {{Towards Scalable and Efficient Processing of Probabilistic Spatial Queries in Mobile Ad Hoc and Sensor Networks}},
   booktitle = {Mobile Datenbanken: heute, morgen und in 20 Jahren. 8. Workshop des GI-Arbeitskreises ``Mobile Datenbanken und Informationssysteme''},
   editor = {Birgitta K{\"o}nig-Ries and Michael Klein},
   address = {Karlsruhe},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {75--84},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2005},
   keywords = {Mobile Ad Hoc Networks; MANETs; MANET; Sensor Networks; WSNs; WSN; Wireless Sensor Networks; Mobile Networks; Queries; Probabilistic Queries; Spatial Queries},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-14/INPROC-2005-14.pdf},
   contact = {Senden Sie eine E-Mail an dudkowski@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the proliferation of sensor technology and advances in wireless communication, gathering, processing, and querying context information in mobile ad hoc and sensor networks becomes attractive and feasible. To support context-aware applications in such networks, efficient processing techniques for frequently used functionality, such as query and event management, are highly beneficial. In this paper, we discuss the challenges in efficient processing of spatial queries in mobile ad hoc and sensor networks. These comprise advanced query semantics based on inaccurate position information, efficient protocols and algorithms for data storage and query resolution, scalability with respect to network size, and support for mobile network nodes. We outline our concepts for solving these issues and show how they can be implemented in a suitable software architecture. Using current evaluation results, we show that our prototype implementation fulfills the stated challenges.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-14&engl=0}
}
@inproceedings {INPROC-2005-12,
   author = {Timo Heiber and Pedro Jose Marron},
   title = {{Exploring the Relationship between Context and Privacy}},
   booktitle = {Privacy, Security and Trust within the Context of Pervasive Computing},
   editor = {Philip Robinson and Harald Vogt and Waleed Wagealla},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {The Kluwer International Series in Engineering and Computer Science},
   volume = {780},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2005},
   isbn = {0-387-23461-6},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications,     K.6.5 Security and Protection},
   contact = {timo.heiber@informatik.uni-stuttgart.de pedro.marron@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Privacy is universally regarded as an important consideration for pervasive computing environments. This is especially true when considering context-aware systems, because of the fact that context often contains personal information. Moreover, an adversary who takes the semantics of the context information into account can potentially infer knowledge beyond the information represented in the actual context data. In this paper, we describe a generic framework to model privacy in context-aware systems and discuss possible inferences based on the context of ID, location and time.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-12&engl=0}
}
@inproceedings {INPROC-2005-11,
   author = {Michael Kinateder and Ernesto Baschny and Kurt Rothermel},
   title = {{Towards a Generic Trust Model}},
   booktitle = {Proceedings of the Third International Conference on Trust Management: iTrust'05; Rocquencourt, France, May 23-26, 2005},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {3477},
   pages = {177--192},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2005},
   isbn = {3-540-26042-0},
   keywords = {Vertrauen, Reputation, Vertrauensmodell, Vertrauensaktualisierung, trust, reputation, trust model, trust-update},
   language = {Englisch},
   cr-category = {I.6.5 Model Development,     I.2.6 Artificial Intelligence Learning,     J.4 Social and Behavioral Sciences,     K.4.4 Electronic Commerce},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-11/INPROC-2005-11.pdf,     http://unitec.informatik.uni-stuttgart.de},
   contact = {Michael Kinateder kinateder@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Research in the area of trust and reputation systems has put a lot of effort in developing various trust models and associated trust update algorithms that support users or their agents with different behavioral profiles. While each work on its own is particularly well suited for a certain user group, it is crucial for users employing different trust representations to have a common understanding about the meaning of a given trust statement. The contributions of this paper are three-fold: Firstly we present the UniTEC generic trust model that provides a common trust representation for the class of trust update algorithms based on experiences. Secondly, we show how several well-known representative trust-update algorithms can easily be plugged into the UniTEC system, how the mappings between the generic trust model and the algorithm-specific trust models are performed, and most importantly, how our abstraction from algorithm-specific details in the generic trust model enables users using different algorithms to interact with each other and to exchange trust statements. Thirdly we present the results of our comparative evaluation of various trust update algorithms under a selection of test scenarios.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-11&engl=0}
}
@inproceedings {INPROC-2005-08,
   author = {Illya Stepanov and Pedro Jose Marron and Kurt Rothermel},
   title = {{Mobility Modeling of Outdoor Scenarios for MANETs}},
   booktitle = {Proceedings of the 38th Annual Simulation Symposium (ANSS 38), San Diego, USA, April 2005},
   publisher = {N/A},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2005},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.4 Performance of Systems,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-08/INPROC-2005-08.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobility of users significantly impacts performance of a mobile ad-hoc network. Most existing simulation tools offer only a few random mobility models, which poorly reflect user movements in outdoor scenarios. For example, they do not consider restrictions of a spatial environment. In this paper, we describe a comprehensive and extensible approach to model mobility of users in outdoor scenarios. It reflects the main factors that influence user movement: spatial environments, user travel decisions, and user movement dynamics. We identify model parameters and show how to set them for concrete scenarios. We provide a simulation environment implementing our approach. For concrete scenarios, the environment supports automatic derivation of some parameters from user position traces.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-08&engl=0}
}
@inproceedings {INPROC-2005-07,
   author = {Susanne B{\"u}rklen and Pedro Jos{\'e} Marr{\'o}n and Serena Fritsch and Kurt Rothermel},
   title = {{User Centric Walk: An Integrated Approach for Modeling the Browsing Behavior of Users on the Web}},
   booktitle = {Proceedings of the 38th IEEE Annual Simulation Symposium (ANSS'05), San Diego, CA, USA},
   editor = {IEEE Computer Society Press},
   address = {San Diego, CA, USA},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2005},
   keywords = {Browsing behavior model; heavy tailed distribution},
   language = {Englisch},
   cr-category = {G.3 Probability and Statistics,     I.6 Simulation and Modeling,     H.1 Models and Principles},
   contact = {Contact: buerklen@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The performance evaluation of Web applications usually requires the utilization of sequences of user requests for determined Web pages. These sequences can be obtained, for example, by applying empirical methods (recording the real sequence of requests), or by applying a formal model for generating synthetic results. In this paper, we present our Web Browsing Model and the User Centric Walk algorithm as its implementation. By taking into account the hyperlink structure as well as the different user behavior on the Web, this algorithm allows us to generate accurate synthetic data that can be used instead of empirically obtained requests. As another contribution of this paper we have shown, based on empirical data, that the probability of choosing some hyperlink from a given page as well as the probability a user leaves a page without following a hyperlink is best characterized by a power-law. Moreover, we show the flexibility and applicability of our model by performing the required correlations to empirical data, which validate our approach.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-07&engl=0}
}
@inproceedings {INPROC-2005-05,
   author = {Uwe-Philipp K{\"a}ppeler and Georg Kindermann and Daniela Nicklas and Nicola H{\"o}nle and Dominique Dudkowski},
   title = {{Shared Dynamic Context Models: Benefits for Advanced Sensor Data Fusion for Autonomous Robots}},
   booktitle = {Proceedings of Artificial Intelligence and Applications 2005; Innsbruck, Austria, February, 14-16, 2005},
   publisher = {IASTED},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2005},
   keywords = {Autonomous; Robots; Sensor; Fusion; Nexus; Context; Sensorfusion},
   language = {Englisch},
   cr-category = {H.3.3 Information Search and Retrieval,     I.2.9 Robotics},
   contact = {kaeppeler@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Bildverstehen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {Information provided by a shared dynamic context model offers new possibilities in the realm of autonomous robots. The availability of external context information can be used by a robot to extend and to validate the locally acquired knowledge about its dynamic environment. A lot of helpful context information is already available in digital form and its quantity will increase rapidly, according to the vision of ubiquitous computing. In this paper we present the Nexus Platform capable of managing a global dynamic context model that can be addressed and accessed in an easy and uniform way by all kinds of context-aware applications (like robots). Advantages for an autonomous wheelchair robot using the Nexus Platform are depicted within an airport scenario. We further present a framework for a sensor fusion agent, able to perform multi-sensor data fusion with selective attention control, concerning the current situation of the environment.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-05&engl=0}
}
@inproceedings {INPROC-2005-03,
   author = {Matthias Grossmann and Martin Bauer and Nicola H{\"o}nle and Uwe-Philipp K{\"a}ppeler and Daniela Nicklas and Thomas Schwarz},
   title = {{Efficiently Managing Context Information for Large-scale Scenarios}},
   booktitle = {Proceedings of the 3rd IEEE Conference on Pervasive Computing and Communications: PerCom2005; Kauai Island, Hawaii, March 8-12, 2005},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2005},
   language = {Englisch},
   cr-category = {H.3.0 Information Storage and Retrieval General,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://www.nexus.uni-stuttgart.de},
   contact = {matthias.grossmann@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Bildverstehen;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we address the data management aspect of large-scale pervasive computing systems. We aim at building an infrastructure that simultaneously supports many kinds of context-aware applications, ranging from room level up to nation level. This allembracing approach gives rise to synergetic benefits like data reuse and sensor sharing. We identify major classes of context data and detail on their characteristics relevant for efficiently managing large amounts of it. Based on that, we argue that for large-scale systems it is beneficial to have special-purpose servers that are optimized for managing a certain class of context data. In the Nexus project we have implemented five servers for different classes of context data and a very flexible federation middleware integrating all these servers. For each of them, we highlight in which way the requirements of the targeted class of data are tackled and discuss our experiences.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-03&engl=0}
}
@inproceedings {INPROC-2005-01,
   author = {Michael Kinateder and Ralf Terdic and Kurt Rothermel},
   title = {{Strong Pseudonymous Communication for Peer-to-Peer Reputation Systems}},
   booktitle = {Proceedings of the 20th Annual ACM Symposium on Applied Computing: SAC'05; Santa Fe, New Mexico, March 13-17, 2005},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1570--1576},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2005},
   isbn = {1-58113-964-0},
   keywords = {privacy, anonymous communication, pseudonyms, extended destination routing, Chaum mixes, mix-cascade, onion routing, distributed hash table, Chord},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     E.3 Data Encryption,     K.4 Computers and Society},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2005-01/INPROC-2005-01.pdf,     http://unitec.informatik.uni-stuttgart.de/},
   contact = {Michael Kinateder kinateder@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper we present a unique approach to enable untraceable communication between pseudonyms. In contrast to the related work, our approach provides strong sender and recipient anonymity most notably by eliminating the need to know of each other's address. We use a variation of Chaum mixes to achieve unlinkability between sender and recipient and introduce a concept called extended destination routing (EDR) which relies on routing headers constructed in multiple layers of encryption and published in a distributed hash table (DHT). When a sender intends to communicate, it contacts the DHT and requests the recipient's routing header, which is then extended and used for routing the message via a mix cascade to this recipient. This work was performed in the context of the UniTEC reputation system and describes the functionality of its anonymous communication layer, which is completely independent of the other UniTEC layers. Although trust and reputation systems in general are typical application areas for our contribution, the presented concepts are easily applicable not only to other reputation systems but also other application areas. We have implemented a prototype of UniTEC and present the first results from an ongoing evaluation in our network emulation testbed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2005-01&engl=0}
}
@inproceedings {INPROC-2004-86,
   author = {Christian Becker and Marcus Handte and Gregor Schiele and Kurt Rothermel},
   title = {{PCOM - A Component System for Pervasive Computing}},
   booktitle = {Proceedings of the Second IEEE International Conference on Pervasive Computing and Communications},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {67--77},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2004},
   keywords = {pervasive computing; ubiquitous computing; system software; component system; 3PC},
   language = {Deutsch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Applications in the Pervasive Computing domain are challenged by the dynamism in which their execution environment changes, e.g. due to user mobility. As a result, applications have to adapt to changes regarding their required resources. In this paper we present PCOM, a component system for Pervasive Computing. PCOM offers application programmers a high-level programming abstraction which captures the dependencies between components using contracts. The resulting application architecture is a tree formed by components and their dependencies. PCOM supports automatic adaptation in cases where the execution environment changes to the better or to the worse. User supplied as well as system provided strategies take users out of the control loop while offering flexible adaptation control.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-86&engl=0}
}
@inproceedings {INPROC-2004-59,
   author = {J{\"o}rg H{\"a}hner and Christian Becker and Pedro Jos{\'e} Marr{\'o}n},
   title = {{Consistent Context Management in Mobile Ad Hoc Networks}},
   booktitle = {Informatik 2004 - Informatik verbindet. Vol. 1},
   editor = {Peter Dadam and Manfred Reichert},
   publisher = {Gesellschaft f{\"u}r Informatik},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Lecture Notes in Informatics},
   volume = {51},
   pages = {308--313},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2004},
   language = {Englisch},
   cr-category = {H.1 Models and Principles},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-59/INPROC-2004-59.pdf},
   contact = {J{\"o}rg H{\"a}hner joerg.haehner@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {John entered his office. John left his office. The order of these updates to a context-aware system is important to reflect the state in the real world. Context information obtained by sensor systems requires consistency concepts which reflect the chronological ordering in which context information has been captured. This paper introduces a consistency concept which allows to express the ordering of events which happened outside of a computer system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-59&engl=0}
}
@inproceedings {INPROC-2004-54,
   author = {Kay R{\"o}mer and Christian Frank and Pedro Marr{\'o}n and Christian Becker},
   title = {{Generic Role Assignment for Wireless Sensor Networks}},
   booktitle = {Proceedings of the 11th ACM SIGOPS European Workshop},
   address = {Leuven, Belgium},
   publisher = {self-publisher},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {7--12},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2004},
   keywords = {sensor network; self-configuration; role assignment},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     C.2.3 Network Operations,     D.3.2 Programming Language Classifications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-54/INPROC-2004-54.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Wireless ad hoc networks of sensor nodes are envisioned to be deployed in the physical environment to monitor a wide variety of real-world phenomena. Almost any sensor network application requires some form of selfconfiguration, where sensor nodes take on specific functions or roles in the network without manual intervention. These roles may be based on varying sensor node properties (e.g., available sensors, location, network neighbors) and may be used to support applications requiring heterogeneous node functionality (e.g., clustering, data aggregation). In this paper we argue that the assignment of user-defined roles is a fundamental part of a wide range of sensor network applications. Consequently, a framework for assignment of roles to sensor nodes in an application-specific manner could significantly ease sensor network programming. We outline the general structure of such a framework and present a first approach to its realization. We demonstrate its utility and feasibility using a number of concrete examples.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-54&engl=0}
}
@inproceedings {INPROC-2004-53,
   author = {Kurt Rothermel and Frank D{\"u}rr},
   title = {{Location-based Services: Auf dem Weg zu kontextbezogenen Informations- und Kommunikationssystemen}},
   booktitle = {Zukunft durch Informationstechnik - Schnell-Mobil-Intelligent -- Jubil{\"a}umsfachtagung 50 Jahre ITG},
   editor = {VDE},
   address = {Frankfurt, Germany},
   publisher = {VDE Verlag GmbH},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {121--128},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2004},
   isbn = {3-8007-2825-7},
   keywords = {Location-based Services; Geocast; Hoarding; Context-aware Systems; Context-aware Computing},
   language = {Deutsch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software,     C.2.2 Network Protocols,     H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-53/INPROC-2004-53.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Die rasant fortschreitende Entwicklung von drahtloser Kommunikation, Positionierungssystemen und Rechnertechnologie sowie deren Integration in multifunktionale Endger{\"a}te unterst{\"u}tzt die vielversprechende neue Anwendungsklasse der ortsbezogenen Systeme. Ortsinformation kann von solchen Anwendungen genutzt werden, um ihr Verhalten dem aktuellen Standort der Benutzer oder auch anderer Objekte anzupassen. Heute schon bieten Netzbetreiber so genannte ``Location-based Services'' an, die prim{\"a}r Navigationsfunktionen und eine ortsbezogene Selektion von Informationen unterst{\"u}tzen. Ortsinformation kann aber auch auf der Systemebene gewinnbringend verwendet werden, etwa zur Bereitstellung neuer ortsbezogener Kommunikationskonzepte oder zur Optimierung der Kommunikation. In diesem Beitrag wird der Begriff der ortsbezogene Anwendungen erl{\"a}utert und Anwendungen dieser Art am Beispiel existierender Systeme kurz skizziert. Au{\ss}erdem werden zwei Beispiele f{\"u}r die Nutzung von Ortsinformation auf Systemebene gegeben, die Geocast-Kommunikation und ein Hoarding-Verfahren.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-53&engl=0}
}
@inproceedings {INPROC-2004-52,
   author = {Pedro Marr{\'o}n and Andreas Lachenmann and Daniel Minder and J{\"o}rg H{\"a}hner and Kurt Rothermel and Christian Becker},
   title = {{Adaptation and Cross-Layer Issues in Sensor Networks}},
   booktitle = {Proceedings of the 2004 Intelligent Sensors, Sensor Networks and Information Processing Conference : ISSNIP '04 ; Melbourne, December 14-17, 2004},
   publisher = {self-publisher},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {623--628},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2004},
   isbn = {0-7803-8894-1},
   keywords = {sensor network; system architecture; adaptation; framework; code distribution; cross-layer},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     D.4.7 Operating Systems Organization and Design},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-52/INPROC-2004-52.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {An intrinsic characteristic of current projects in the area of sensor networks is the heterogeneity of hardware and application requirements. In addition, the requirements of current applications are expected to change over time. This makes developing, deploying, and optimizing sensor network applications an extremely difficult task. In this paper, we present the architecture of TinyCubus, a flexible and adaptive crosslayer framework for TinyOS-based sensor networks that aims at providing the necessary infrastructure to cope with the complexity of such systems. TinyCubus consists of three parts: a data management framework that selects and adapts both system and data management components, a cross-layer framework that enables optimizations through cross-layer interactions, and a configuration engine that installs components dynamically. We show the feasibility of our architecture by describing and evaluating a code distribution algorithm that optimizes its behavior by using application knowledge about the sensor topology.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-52&engl=0}
}
@inproceedings {INPROC-2004-38,
   author = {Christian Becker and Daniela Nicklas},
   title = {{Where do spatial context-models end and where do ontologies start? A proposal of a combined approach}},
   booktitle = {Proceedings of the First International Workshop on Advanced Context Modelling, Reasoning and Management in conjunction with UbiComp 2004},
   editor = {Jadwiga Indulska and David De Roure},
   address = {Nottingham, England},
   publisher = {University of Southhampton},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {48--53},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2004},
   isbn = {854328130},
   keywords = {Context-Models, Adaptation, Infrastructures for Context-Aware Computing, Ubiquitous Computing},
   language = {Deutsch},
   cr-category = {H.2.1 Database Management Logical Design},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-38/INPROC-2004-38.pdf},
   contact = {christian.becker@informatik.uni-stuttgart.de, daniela.nicklas@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {Context-aware applications adapt their behavior depending on the state of the physical world along with other information representing context. This requires context management, i.e., the efficient management of context information and feasible context representations in order to allow reasoning. This paper discusses two common approaches, spatial context models and contextual ontologies, and argues for a combined approach providing the efficiency of context management through context models combined with the semantic expressiveness of ontologies.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-38&engl=0}
}
@inproceedings {INPROC-2004-29,
   author = {Frank D{\"u}rr and Nicola H{\"o}nle and Daniela Nicklas and Christian Becker and Kurt Rothermel},
   title = {{Nexus--A Platform for Context-Aware Applications}},
   booktitle = {1. GI/ITG Fachgespr{\"a}ch Ortsbezogene Anwendungen und Dienste.},
   editor = {J{\"o}rg Roth},
   address = {Hagen},
   publisher = {FernUniversit{\"a}t in Hagen},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Informatik-Berichte der FernUniversit{\"a}t in Hagen},
   volume = {317},
   pages = {15--18},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2004},
   keywords = {Location-based Service; Context-aware System; Platform; Geocast},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.2.4 Database Management Systems,     H.2.8 Database Applications,     H.3.4 Information Storage and Retrieval Systems and Software,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-29/INPROC-2004-29.pdf},
   contact = {Senden Sie eine E-Mail an frank.duerr@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {In this paper we present the Nexus Platform for context-aware applications. This platform allows to share the effort of setting up a global and detailed context model between different providers by federating their partial models. Applications can query data directly, use push-based communication through an event service, or use value-added services like a navigation or map service for special tasks. Additional context-aware services like hoarding or geocast can be implemented on basis of the platform. For the latter we present different approaches for addressing and efficient message forwarding based on the Nexus Platform.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-29&engl=0}
}
@inproceedings {INPROC-2004-28,
   author = {J{\"o}rg H{\"a}hner and Kurt Rothermel and Christian Becker},
   title = {{Update-Linearizability: A Consistency Concept for the Chronological Ordering of Events in MANETs}},
   booktitle = {Proceedings of the First IEEE International Conference on Mobile Ad Hoc and Sensor Systems},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--10},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2004},
   language = {Englisch},
   cr-category = {H.2 Database Management,     C.2 Computer-Communication Networks},
   contact = {J{\"o}rg H{\"a}hner haehner@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobile ad hoc networks (MANETs) are used in situations where networks need to be deployed immediately but no network infrastructure is available. If MANET nodes have sensing capabilities, they can capture and communicate the state of their surroundings, including environmental conditions or objects in their proximity. If the sensed state information is propagated to a database to build a consistent model of the real world, a variety of promising context-aware applications becomes possible. In this paper, we introduce a novel consistency concept that preserves the chronological ordering of sensed state transition events. Based on this concept, we propose a data replication algorithm for MANETs that guarantees the consistency concept without relying on synchronized clocks and show its correctness. Our simulation experiments show that replicated copies are updated regularly even if the network load in the system is high.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-28&engl=0}
}
@inproceedings {INPROC-2004-27,
   author = {Gregor Schiele and Christian Becker and Kurt Rothermel},
   title = {{Energy-Efficient Cluster-based Service Discovery}},
   booktitle = {Proceedings of the 11th ACM SIGOPS European Workshop (SIGOPSEW04); Leuven, Belgium, September 20-22, 2004},
   publisher = {ACM SIGOPS},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {75--79},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2004},
   keywords = {SANDMAN; service discovery; energy-efficient; energy-aware},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   contact = {gregor.schiele@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Service discovery in Ubiquitous Computing is a task which has to be done frequently due to dynamically changing environments. The limited battery power of mobile devices requires us to optimize frequent and energy costly tasks, especially the ones incurring in communication activities. In this paper we present a novel service discovery algorithm based on node clustering. Nodes within a cluster may sleep to save energy when idle. A clusterhead node is always active and answers discovery requests on behalf of other nodes to achieve low discovery latencies. Simulation experiments show energy savings of up to 66\% compared to an approach where all nodes are permanently active while the discovery latencies were not increased.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-27&engl=0}
}
@inproceedings {INPROC-2004-26,
   author = {Daniel Herrscher and Steffen Maier and Jing Tian and Kurt Rothermel},
   title = {{A Novel Approach to Evaluating Implementations of Location-Based Software}},
   booktitle = {Proceedings of the 2004 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2004), San Jose, CA, USA, July 26-29, 2004.},
   publisher = {SCS},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {484--490},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2004},
   isbn = {1-56555-284-9},
   keywords = {performance analysis; network emulation; location-based software; positioning devices; mobile ad hoc networks},
   language = {Englisch},
   cr-category = {D.4.4 Operating Systems Communications Management,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-26/INPROC-2004-26.pdf,     http://net.informatik.uni-stuttgart.de/},
   contact = {herrscher@informatik.uni-stuttgart.de, maier@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {There are two main approaches to measuring the performance of location-based software for mobile ad hoc networks: live testing and measurements in an emulation testbed. The former is problematic because of high resource costs and low reproducibility. The latter offers the advantage of reproducible network conditions in the laboratory. In addition, location-based software has to be provided with appropriate location information. We develop virtual devices that mimic the interface and functionality of actual positioning devices, and integrate these into an existing network emulation testbed. The combination of mobile network emulation and positioning device emulation facilitates the evaluation of location-based software in different scenarios. We provide sample measurements using an existing location-based adhoc routing protocol implementation for inter-vehicle communication in a scenario with 50 emulated cars. The results are in good agreement with the available simulations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-26&engl=0}
}
@inproceedings {INPROC-2004-24,
   author = {Tobias Drosdol and Thomas Schwarz and Martin Bauer and Matthias Gro{\ss}mann and Nicola H{\"o}nle and Daniela Nicklas},
   title = {{Keeping Track of ``Flying Elephants'': Challenges in Large-Scale Management of Complex Mobile Objects}},
   booktitle = {Proceedings of INFORMATIK 2004 - the Thirty-Fourth Annual Conference of the Gesellschaft f{\"u}r Informatik e.V.(GI); Ulm, Germany, September 20-24, 2004. Vol. 1},
   editor = {Peter Dadam and Manfred Reichert},
   address = {Bonn},
   publisher = {K{\"o}llen Druck+Verlag GmbH},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Lecture Notes in Informatics},
   volume = {P-50},
   pages = {288--292},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2004},
   isbn = {3-88579-379-2},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.2.4 Database Management Systems,     H.2.8 Database Applications,     H.3.4 Information Storage and Retrieval Systems and Software},
   contact = {Tobias Drosdol Tobias.Drosdol@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The management of mobile objects like cars, persons, or workpieces in a factory is an important task in many context-aware environments. So far, most solutions can either cope with many small objects (few properties) or with a limited number of complex objects in a centralized way. In this paper, we face the challenge of managing a large number of bulky mobile objects (flying elephants). We state requirements, propose basic components, and discuss alternative architectures based on the main influencing factors like mobility and update rate.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-24&engl=0}
}
@inproceedings {INPROC-2004-18,
   author = {Martin Bauer and Lamine Jendoubi and Oliver Siemoneit},
   title = {{Smart Factory – Mobile Computing in Production Environments}},
   booktitle = {Proceedings of the MobiSys 2004 Workshop on Applications of Mobile Embedded Systems (WAMES 2004)},
   publisher = {WWW},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2004},
   keywords = {Smart Factory, Production Environment, Mobile Computing, Context-aware Applications},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.2.4 Database Management Systems,     H.3.3 Information Search and Retrieval,     J.1 Administration Data Processing},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-18/INPROC-2004-18.pdf,     http://lcawww.epfl.ch/luo/WAMES%202004.htm,     http://lcawww.epfl.ch/luo/WAMES%202004_files/Smart%20Factory.pdf},
   contact = {Martin Bauer Martin.Bauer@informatik.uni-stuttgart.de Lamine Jendoubi LAJ@iff.uni-stuttgart.de Oliver Siemoneit Oliver.Siemoneit@philo.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Philosophie, Abteilung f{\"u}r Wissenschaftstheorie und Technikphilosophie (IP/WTTP);     Universit{\"a}t Stuttgart, Institut f{\"u}r Industrielle Fertigung und Fabrikbetrieb (IFF)},
   abstract = {Companies want to provide their customers with highly individualized products so as to gain sustainable advantages over their competitors. The high degree of individualization has also deep effects on the production: it demands a vast amount of highly specialized tools for certain steps in the production process and a frequent changing of machinery settings and tools. As a result, the management of production resources and their coordination become quite dynamic and complex, so that existing resource management systems are too static to handle them. This paper shows how the use of pervasive and mobile computing can help companies to address the resulting problems. It derives the requirements and identifies resulting research challenges, especially pertaining to the mobility and dynamic state of the tools. Finally, the Nexus platform is presented and it is shown how some of the identified challenges are addressed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-18&engl=0}
}
@inproceedings {INPROC-2004-16,
   author = {Martin Bauer and Kurt Rothermel},
   title = {{How to Observe Real-World Events through a Distributed World Model}},
   booktitle = {Proceedings of the Tenth International Conference on Parallel and Distributed Systems 2004 (ICPADS 2004);Newport Beach, California, July 7-9, 2004},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {467--476},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2004},
   keywords = {distributed systems; event systems; event observation; real-world events; world model; distributed world model; occurrence probability},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.3 Information Search and Retrieval,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {www.nexus.uni-stuttgart.de},
   contact = {Martin Bauer Martin.Bauer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The observation of events is important in application areas where large amounts of dynamic data are created all the time and the user just wants to be notified when this data indicates that an event of interest has occurred. Typically, these are real-world events, but are observed through a model providing the relevant data about the state of the physical world. An example are spatial events, i.e. events that occur when a user enters a certain spatial relationship with other users or his environment. If the model consists of local models that together form a large, but distributed, global model, a number of issues have to be dealt with to allow the observation of events. To the best of our knowledge, this paper is the first to propose a uniform approach for observing real-world events through a distributed world model. The state of the world is only available with limited accuracy in both the value and time dimension, which is due to sensor inaccuracy and the properties of the distributed system. Therefore, it is not always possible to determine for certain, if an event has occurred. We propose a uniform approach to this problem based on calculating the probability with which an event has occurred. The event is considered to have occurred when the calculated probability is above a threshold probability specified by the user. To realize this approach, we show which system parameters influence the observation, how update protocols provide the data to the observer model, on which the event is actually observed, and how the probability that an event has occurred can be calculated based on this model.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-16&engl=0}
}
@inproceedings {INPROC-2004-07,
   author = {Michael Kinateder and Kurt Rothermel},
   title = {{Bringing Confidence to the Web - Combining the Power of SET and Reputation Systems}},
   booktitle = {Proceedings of the 2004 IEEE Consumer Communications \& Networking Conference: CCNC 2004; Las Vegas, Nevada, USA, January 5-8, 2004},
   address = {Las Vegas, Nevada, USA},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {545--550},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2004},
   isbn = {0-7803-8145-9},
   keywords = {trust; reputation; reputation system; recommendation; recommendation system; payment; payment system; SET; secure electronic transaction},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     C.2.4 Distributed Systems,     K.4.4 Electronic Commerce,     K.6.5 Security and Protection},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-07/INPROC-2004-07.pdf,     http://unitec.informatik.uni-stuttgart.de/,     http://www.ccnc2004.org},
   contact = {Michael Kinateder kinateder@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Reputation systems suffer from easy copying of recommendations and recommenders attaching themselves to trustworthy recommenders to benefit from their good reputation. Electronic commerce in general and electronic payment systems in particular suffer from the uncertainty of potential customers about the reputation of online merchants and the quality of the offered goods or services. In this paper we address these issues to a certain degree by creating an originality statement in the payment process that is included in recommendations to prove, that a particular recommendation is indeed linked to a real world transaction. We present the initial protocol and two variations and discuss their distinct features. Although the protocol is described working in conjunction with the SET payment scheme, it is easily applicable to other payment systems with the features outlined in this paper.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-07&engl=0}
}
@inproceedings {INPROC-2004-06,
   author = {J{\"o}rg H{\"a}hner and Dominique Dudkowski and Pedro Jos{\'e} Marr{\'o}n and Christian Becker},
   title = {{Partitioning in Mobile Ad Hoc Networks}},
   booktitle = {2. GI/ITG KuVS-Fachgespr{\"a}ch ``Drahtlose Sensornetzwerke''},
   address = {Karlsruhe, Germany},
   publisher = { },
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2004},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     D.2.8 Software Engineering Metrics},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The performance of distributed algorithms in mobile ad hoc networks is strongly influenced by the connectivity of the network. In cases where the connectivity is low, network partitioning occurs. The mobility and density of network nodes, i.e. the movement of nodes and the number of nodes per unit area, are fundamental properties that have a large impact on the partitioning behavior, so that a detailed characterization of this behavior may be applied to improve the performance of distributed algorithms. In this paper we introduce a set of metrics that describe characteristics regarding partitioning in mobile ad hoc networks. We have conducted an extensive set of simulation studies for a wide range of network scenarios to show the impact of node mobility and density on the proposed metrics. We present results for the number of partitions, their size over time, and the frequency of partition changes. From the perspective of individual nodes, we introduce metrics that describe the time periods in which pairs of nodes are located in different partitions, and the number of nodes that are in the partition of an individual node over time. The results obtained in this paper will allow distributed data management algorithm designers to characterize those types of network scenarios where partitioning must be explicitly considered. Especially algorithms in areas such as replication, data storage, and query processing, may be inspired by the results at hand. Finally, the optimization of strategies for replica placement, update frequency, spatial scoping of data, and even more advanced techniques for data exchange between nodes in frequently partitioned networks will also benefit from our results.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-06&engl=0}
}
@inproceedings {INPROC-2004-05,
   author = {J{\"o}rg H{\"a}hner and Dominique Dudkowski and Pedro Jos{\'e} Marr{\'o}n},
   title = {{A Quantitative Analysis of Partitioning in Mobile Ad Hoc Networks}},
   booktitle = {Accepted for Poster at the Joint International Conference on Measurement and Modeling of Computer Systems : Sigmetrics - Performance 2004},
   publisher = { ACM},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2004},
   keywords = {mobile ad hoc networks, network topology, partition metrics},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     D.2.8 Software Engineering Metrics},
   contact = {Please send an email to joerg.haehner@informatik.uni-stuttgart.de or dominique.dudkowski@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The performance of distributed algorithms in mobile ad hoc networks is strongly influenced by the connectivity of the network. In cases where the connectivity is low, network partitioning occurs. The mobility and density of network nodes, i.e. the movement of nodes and the number of nodes per unit area, are fundamental properties that have a large impact on the partitioning behavior, so that a detailed characterization of this behavior may be applied to improve the performance of distributed algorithms. In this paper we introduce a set of metrics that describe characteristics regarding partitioning in mobile ad hoc networks. We have conducted an extensive set of simulation studies for a wide range of network scenarios to show the impact of node mobility and density on the proposed metrics. We present results for the number of partitions, their size over time, and the frequency of partition changes. From the perspective of individual nodes, we introduce metrics that describe the time periods in which pairs of nodes are located in different partitions, and the number of nodes that are in the partition of an individual node over time. The results obtained in this paper will allow distributed data management algorithm designers to characterize those types of network scenarios where partitioning must be explicitly considered. Especially algorithms in areas such as replication, data storage, and query processing, may be inspired by the results at hand. Finally, the optimization of strategies for replica placement, update frequency, spatial scoping of data, and even more advanced techniques for data exchange between nodes in frequently partitioned networks will also benefit from our results.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-05&engl=0}
}
@inproceedings {INPROC-2004-04,
   author = {Arno Wacker and Timo Heiber and Holger Cermann and Pedro Marron},
   title = {{A fault-tolerant Key-Distribution Scheme for Securing Wireless Ad-Hoc Networks}},
   booktitle = {Proceedings of the Second International Conference on Pervasive Computing},
   address = {Vienna, Austria},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2004},
   keywords = {wireless, ad-hoc networks, security, key-distribution, fault tolerance},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.3 Special-Purpose and Application-Based Systems,     G.2.2 Discrete Mathematics Graph Theory},
   ee = {http://www.pervasive2004.org},
   contact = {Arno Wacker Arno.Wacker@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {We propose a novel solution for securing wireless ad-hoc networks. Our goal is to provide secure key exchange in the presence of device failures and denial-of-service attacks. The proposed solution relies solely on symmetric cryptography and therefore is applicable for highly resource-limited devices. In order to avoid a single point of trust, no master device or base station is used. We achieve this by enhancing our previously published approach with redundancy and algorithms for recovery on device failures.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-04&engl=0}
}
@inproceedings {INPROC-2004-03,
   author = {Arno Wacker and Timo Heiber and Holger Cermann},
   title = {{A Key-Distribution Scheme for Wireless Home Automation Networks}},
   booktitle = {Proceedings of the first IEEE Consumer Communications and Networking Conference: CCNC04; January 5-8, 2004},
   address = {Las Vegas, Nevada, USA},
   publisher = {IEEE Communications Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2004},
   isbn = {0-7803-8145-9},
   keywords = {wireless, ad-hoc networks, security, key-distribution},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     C.3 Special-Purpose and Application-Based Systems,     G.2.2 Discrete Mathematics Graph Theory},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2004-03/INPROC-2004-03.pdf,     http://www.ccnc2004.org},
   contact = {Arno Wacker Arno.Wacker@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Wireless home automation networks are one example of how wireless technologies may soon become part of our daily life, yet security in existing products is woefully inadequate. An important problem in this area is the question of secure key distribution. In this paper we present a key-distribution scheme geared towards home automation networks, but applicable to other networks with related properties as well. Our approach uses a decentralized scheme that is designed to work on resource-poor devices, allows easy addition and removal of devices and limits the workload on the end user while guaranteeing the secrecy of the exchanged keys even in the presence of subverted nodes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-03&engl=0}
}
@inproceedings {INPROC-2004-02,
   author = {Othmar Lehmann and Martin Bauer and Christian Becker and Daniela Nicklas},
   title = {{From Home to World - Supporting Context-aware Applications through World Models}},
   booktitle = {Proceedings of the Second IEEE International Conference on Pervasive Computing and Communications},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {297--306},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2004},
   keywords = {context; context-awareness; pervasive computing; ubiquitous computing; world model; Nexus},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.2.1 Database Management Logical Design,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://www.percom.org/,     http://www.nexus.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware},
   abstract = {In the vision of pervasive computing smart everyday objects communicate and cooperate to provide services and information to users. Interoperability between devices and applications not only requires common protocols but also common context management. In this paper we discuss requirements on the context management based on the Georgia Tech's Aware Home environment and the global context management perspective of the Nexus project. Our experiences with integrating the Aware Home Spatial Service into the Nexus platform show how federation concepts and a common context model can provide applications with uniform context information in different administrative and application domains.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-02&engl=0}
}
@inproceedings {INPROC-2004-01,
   author = {Susanne B{\"u}rklen and Pedro Jos{\'e} Marr{\'o}n and Kurt Rothermel},
   title = {{An Enhanced Hoarding Approach Based on Graph Analysis}},
   booktitle = {Proceedings of the 5th IEEE International Conference on Mobile Data Management (MDM 2004); Berkeley, California, USA; January 19-22, 2004},
   address = {Los Alamitos},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {358--369},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2004},
   language = {Englisch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software,     I.5.3 Pattern Recognition Clustering},
   ee = {http://www.nexus.uni-stuttgart.de/},
   contact = {buerklse@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The proliferation of mobile devices has led to the creation of hoarding algorithms that attempt to mitigate the problems related with disconnected operation or with the operation in areas where bandwidth is either scarce or very expensive. Traditional hoarding approaches use probability access tables to determine what information needs to be sent to the mobile device, but fail to take the structured nature of data into account. In this paper, we present an enhanced hoarding approach for semistructured information that relies on the analysis of graphs to determine the information that needs to be hoarded. We show by means of experimental evaluations on webpages that our approach outperforms other hoarding algorithms that treat information as the combination of unrelated items.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2004-01&engl=0}
}
@inproceedings {INPROC-2003-65,
   author = {Illya Stepanov and J{\"o}rg H{\"a}hner and Christian Becker and Jing Tian and Kurt Rothermel},
   title = {{A Meta-Model and Framework for User Mobility in Mobile Networks}},
   booktitle = {Proceedings of the 11th International Conference on Networking 2003 (ICON 2003), Sydney, Australia, September 28 - October 1, 2003},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {231--238},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2003},
   isbn = {0-7803-7788-5},
   keywords = {simulation; mobility modeling; user movement},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.4 Performance of Systems,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-65/INPROC-2003-65.pdf,     http://canu.informatik.uni-stuttgart.de/mobisim},
   contact = {illya.stepanov@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Mobility patterns play an important role for performance evaluations of mobile networks. To simulate user movement, existing simulation tools provide only a few simple mobility models (e.g., random movement) suitable for particular scenarios. To evaluate a new scenario, an appropriate model needs to be created, but this requires extra work that distracts the researcher from his/her main task. In general, three key elements determine the mobility of users: the spatial environment, the user trip sequences, and the user movement dynamics (e.g., speed). In this paper, we introduce a meta-model that integrates these three elements in an easy-to-use framework, allowing a flexible modeling of user mobility in custom scenarios. The framework is available for download as a stand-alone trace generator and may be used together with any simulation or emulation tool for mobile networks to evaluate a specific scenario.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-65&engl=0}
}
@inproceedings {INPROC-2003-36,
   author = {Jing Tian and Lu Han and Kurt Rothermel and Christian Cseh},
   title = {{Spatially Aware Packet Routing for Mobile Ad Hoc Inter-Vehicle Radio Networks}},
   booktitle = {Proceedings of the IEEE 6th International Conference on Intelligent Transportation Systems (ITSC). Vol. 2},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1546--1552},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2003},
   isbn = {0-7803-8125-4},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-36/INPROC-2003-36.pdf},
   contact = {jing.tian@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Inter-Vehicle Communication will become an important building block for ITS telematics applications like safety and warning functions. Mobile ad hoc networks (MANETs) can serve as a local wireless network for exchanging information between cars for cooperative driver assistance applications. For the routing of data packets in such large-scale MANETs consisting of vehicles on the road, geographic multi-hop packet forwarding is a promising approach. However, a main drawback is that it performs poorly in networks with many topology holes. In this paper, we propose a spatially aware packet routing approach to predict permanent topology holes caused by spatial constraints and avoid them aforehand. This approach is generic and can be used in combination with any existing geographic forwarding protocol as an extension. Our simulations demonstrate that spatial awareness can significantly improve geographic forwarding performance in situations with many permanent topology holes, like in dynamic vehicle networks.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-36&engl=0}
}
@inproceedings {INPROC-2003-26,
   author = {Marcus Handte and Christian Becker and Gregor Schiele},
   title = {{Experiences: Minimalism and Extensibility in BASE}},
   booktitle = {Proceedings of the System Support for Ubiquitous Computing Workshop (Ubisys03) at the Fifth Annual Conference on Ubiquitous Computing (Ubicomp03); Seattle, Washington, October 12, 2003},
   publisher = {online proceedings},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--8},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2003},
   keywords = {micro-broker; BASE; PCOM; 3PC; ubiquitous computing; pervasive computing; middleware},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures,     D.2.12 Software Engineering Interoperability,     D.4.4 Operating Systems Communications Management},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-26/INPROC-2003-26.pdf,     http://ciae.cs.uiuc.edu/ubisys/program.html,     http://ciae.cs.uiuc.edu/ubisys/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In the vision of Ubiquitous Computing everyday objects become smart. Technically, this requires some sort of processing and communication technology. We have designed and implemented a middleware for spontaneous networking in Ubiquitous Computing environments. The major objectives were minimalism and extensibility in order to deploy the middleware on a variety of devices ranging from sensor nodes to classical general purpose computers. In this paper we will assess the taken approach based on two follow-up projects: the port of BASE to a small embedded system and the design and implementation of a component system on top of BASE. While the fundamental concepts and design principles of BASE have proven to be solid, both projects provided insights that led to minor conceptual and major technical changes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-26&engl=0}
}
@inproceedings {INPROC-2003-24,
   author = {Frank D{\"u}rr and Kurt Rothermel},
   title = {{On a Location Model for Fine-Grained Geocast}},
   booktitle = {UbiComp 2003: Ubiquitous Computing (Proceedings of the Fifth International Conference on Ubiquitous Computing 2003); Seattle, WA, October 2003},
   editor = {Anind K. Dey and Albrecht Schmidt and Joseph F. McCarthy},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Lecture Notes in Computer Science},
   volume = {2864},
   pages = {18--35},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2003},
   isbn = {3-540-20301-X},
   keywords = {Ubiquitous Computing; Location Model; Geocast},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-24/INPROC-2003-24.pdf,     http://www.springerlink.com/content/e9apt8y1w5nmem89/},
   contact = {frank.duerr@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Geographic communication (geocast) is used to send messages to geographic areas, e.g. to distribute warning messages or other information within these areas. It is based on a location model which is used to determine a message's target area and the receivers' positions and therefore has strong influence on the achievable granularity of geographic addressing. A hybrid location model and and a fine-grained addressing scheme for geocast based on this model are presented in this paper which support two- and three-dimensional geometric locations as well as symbolic locations like room numbers, embedded local coordinate systems, and mobile target areas like trains.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-24&engl=0}
}
@inproceedings {INPROC-2003-21,
   author = {Martin Bauer and Lamine Jendoubi and Kurt Rothermel and Engelbert Westk{\"a}mper},
   title = {{Grundlagen ubiquit{\"a}rer Systeme und deren Anwendung in der ``Smart Factory''}},
   booktitle = {Industrie Management - Zeitschrift f{\"u}r industrielle Gesch{\"a}ftsprozesse},
   editor = {Norbert Gronau and Hermann Krallmann and Bernd Scholz-Reiter},
   address = {Berlin},
   publisher = {GITO mbH Verlag f{\"u}r Industrielle Organisation},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   volume = {19},
   number = {6},
   pages = {17--20},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2003},
   keywords = {Smart Factory; Ubiquitous Computing; R{\"a}umliche Umgebungsmodelle; kontext-bezogene Systeme; context-aware systems; spatial world models; Nexus},
   language = {Deutsch},
   cr-category = {C.2.4 Distributed Systems,     H.2.4 Database Management Systems,     H.2.8 Database Applications,     H.3.4 Information Storage and Retrieval Systems and Software,     J.1 Administration Data Processing,     J.7 Computers in Other Systems},
   ee = {http://www.nexus.uni-stuttgart.de,     http://www.industrie-management.de},
   contact = {Kurt.Rothermel@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Industrielle Fertigung und Fabrikbetrieb (IFF)},
   abstract = {Die rasch fortschreitende Entwicklung kleiner mobiler Ger{\"a}te sowie mit eingebetteter Sensorik und Aktorik versehener Alltagsgegenst{\"a}nde erm{\"o}glicht eine Vielzahl neuartiger Anwendungen. Die F{\"a}higkeit zur drahtlosen Kommunikation und zur Positionsbestimmung bereitet die Basis lokations- und kontextbezogener Systeme, die seit einigen Jahren im Projekt Nexus an der Universit{\"a}t Stuttgart untersucht werden. Der Einsatz dieser Technologien im produktionstechnischem Umfeld, z.B. der hier vorgestellten dezentralen Betriebsmittelverwaltung, er{\"o}ffnet dabei ein vollkommen neues Anwendungsgebiet.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-21&engl=0}
}
@inproceedings {INPROC-2003-20,
   author = {Kurt Rothermel and Dominique Dudkowski and Frank D{\"u}rr and Martin Bauer and Christian Becker},
   title = {{Ubiquitous Computing - More than Computing Anytime Anyplace?}},
   booktitle = {Proceedings of the 49. Photogrammetrische Woche},
   address = {Stuttgart},
   publisher = {ifp},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2003},
   keywords = {Kontext; kontextbezogene Systeme; Ubiquitous Computing; Nexus},
   language = {Deutsch},
   cr-category = {H.2.8 Database Applications,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-20/INPROC-2003-20.pdf,     http://www.nexus.uni-stuttgart.de},
   contact = {Kurt.Rothermel@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The rapid development of mobile communication networks and the availability of miniaturized and inexpensive sensor technology allow for the development of multifunctional mobile devices that are able to collect and communicate context information. We also currently see a clear trend towards the integration of embedded systems including sensors into {\ss}mart`` everyday things, which is also referred to as Ubiquitous Computing. The deployment of sensor technology allows for so-called context-aware applications, going far beyond of providing mobile access to information and computing resources. Context-aware applications exploit captured sensor information to adapt to the current situation of mobile users. For instance, the information offered to a user may depend on his current location, and the way how it is presented to him may depend on the speed he moves, whether he is on its own or with others, and so on. In this paper, we characterize context-aware applications and present the vision of a digital world model as the foundation for this class of applications. Further, the paper discusses the benefits and reseach challenges associated with digital world models, which allow applications to take into account the state of the real world and react to state changes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-20&engl=0}
}
@inproceedings {INPROC-2003-19,
   author = {Audun J{\o}sang and Elizabeth Gray and Michael Kinateder},
   title = {{Analysing Topologies of Transitive Trust}},
   booktitle = {Proceedings of the First International Workshop on Formal Aspects in Security \& Trust: FAST 2003; Pisa, Italy, September 2003},
   publisher = {IIT-CNR},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {9--22},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2003},
   keywords = {trust; transitive; reputation; recommendation},
   language = {Englisch},
   cr-category = {J.4 Social and Behavioral Sciences,     C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-19/INPROC-2003-19.pdf,     http://unitec.informatik.uni-stuttgart.de/},
   contact = {Michael Kinateder Kinateder@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Transacting and interacting through computer networks makes it difficult to use traditional methods for establishing trust between parties. Creating substitutes by which people, organisations and software agents can derive trust in others through computer networks requires computerised analysis of trust topologies. This paper describes diverse dimensions of trust that are needed for analysing trust topologies, and provides a notation with which to express trust relationships in terms of these dimensions. The result is a simple way of specifying topologies of trust from which derived trust relationships can be automatically and securely computed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-19&engl=0}
}
@inproceedings {INPROC-2003-18,
   author = {Michael Kinateder and Siani Pearson},
   title = {{A Privacy-Enhanced Peer-to-Peer Reputation System}},
   booktitle = {Proceedings of the 4th International Conference on Electronic Commerce and Web Technologies: EC-Web 2003; Prague, Czech Republic, September 2003},
   editor = {Kurt Bauknecht and A Min Tjoa and Gerald Quirchmayr},
   address = {Heidelberg},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {2738},
   pages = {206--215},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2003},
   isbn = {3-540-40808-8},
   keywords = {trust; reputation; recommendation; trusted platforms; trusted computing platform alliance; TCPA; trusted computing group; TCG; privacy; security},
   language = {Englisch},
   cr-category = {B.8 Performance and Reliability,     D.4.6 Operating Systems Security and Protection,     H.3.4 Information Storage and Retrieval Systems and Software,     H.3.5 Online Information Services,     H.4.2 Information Systems Applications Types of Systems,     K.4.1 Computers and Society Public Policy Issues,     K.4.4 Electronic Commerce,     K.6.5 Security and Protection},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-18/INPROC-2003-18.pdf,     http://unitec.informatik.uni-stuttgart.de/},
   contact = {Michael Kinateder kinateder@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, a method is described for providing a distributed reputation system with enhanced privacy and security as a design feature. This is achieved using a network of trusted agents on each client platform that exploit Trusted Computing Platform Alliance (TCPA) technology.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-18&engl=0}
}
@inproceedings {INPROC-2003-17,
   author = {Kurt Rothermel and Dieter Fritsch and Bernhard Mitschang and Paul J. K{\"u}hn and Martin Bauer and Christian Becker and Christian Hauser and Daniela Nicklas and Steffen Volz},
   title = {{SFB 627: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme}},
   booktitle = {Proceedings Informatik 2003},
   address = {Frankfurt},
   publisher = {Gesellschaft f{\"u}r Informatik},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2003},
   keywords = {Umgebungsmodelle; kontext-bezogene Systeme; Nexus; Spatial World Models; context-aware systems},
   language = {Deutsch},
   cr-category = {C.2.4 Distributed Systems,     H.2.4 Database Management Systems,     H.2.8 Database Applications,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://www.nexus.uni-stuttgart.de},
   contact = {Kurt.Rothermel@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Kommunikationsnetze und Rechnersysteme (IKR);     Universit{\"a}t Stuttgart, Institut f{\"u}r Photogrammetrie (ifp)},
   abstract = {Ziel des Sonderforschungsbereichs 627 ``Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme'' ist die Erforschung von Methoden und Verfahren f{\"u}r die Definition, die Verwaltung und die Nutzung von digitalen Umgebungsmodellen. Existierende Informationsr{\"a}ume werden mit komplexen Modellen der realen Welt verschr{\"a}nkt und erlauben so neuartige Anwendungen. Insbesondere die Klasse der ortsbezogenen Anwendungen und aktuelle Forschungsgebiete wie das Ubiquitous Computing k{\"o}nnen von solchen Umgebungsmodellen profitieren, oder werden durch sie erst erm{\"o}glicht.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-17&engl=0}
}
@inproceedings {INPROC-2003-13,
   author = {Christian Becker and Gregor Schiele and Holger Gubbels and Kurt Rothermel},
   title = {{BASE - A Micro-broker-based Middleware For Pervasive Computing}},
   booktitle = {Proceedings of the First IEEE International Conference on Pervasive Computing and Communication (PerCom), March 23-26, Fort Worth, USA},
   address = {Los Alamitos},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {443--451},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2003},
   isbn = {0-7695-1895},
   keywords = {Middleware, Ubiquitous Computing, Microbroker, Micro-broker, BASE},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-13/INPROC-2003-13.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive computing environments add a multitude of additional devices to our current computing landscapes. Specialized embedded systems provide sensor information about the real world or offer a distinct functionality, e.g. presentation on a “smart wall”. Spontaneous networking leads to constantly changing availability of services. This requires middleware support to ease application development. Additionally, we argue that an extensible middleware platform covering small embedded systems to full-fledged desktop computers is needed. Such a middleware should provide easy-to-use abstractions to access remote services and device-specific capabilities. We present a micro-broker- based approach which meets these requirements by allowing uniform access to device capabilities and services through proxies and the integration of different interoperability protocols. A minimum configuration of the middleware can be executed on embedded systems. Resource-rich execution environments are supported by the extensibility of the middleware.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-13&engl=0}
}
@inproceedings {INPROC-2003-12,
   author = {Daniel Herrscher and Steffen Maier and Kurt Rothermel},
   title = {{Distributed Emulation of Shared Media Networks}},
   booktitle = {Proceedings of the 2003 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2003), Montr{\'e}al, Quebec, Canada, July 20-24, 2003},
   publisher = {SCS},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {226--233},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2003},
   isbn = {1-56555-269-5},
   keywords = {network emulation; distributed emulation; performance analysis; shared media; CSMA/CD},
   language = {Englisch},
   cr-category = {C.2.5 Local and Wide-Area Networks,     D.4.4 Operating Systems Communications Management,     I.6.3 Simulation and Modeling Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-12/INPROC-2003-12.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-12/INPROC-2003-12.ps,     http://net.informatik.uni-stuttgart.de/},
   contact = {herrscher@informatik.uni-stuttgart.de, maier@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Comparative performance measurements of distributed applications and network protocols require the availability of appropriate network environments. Network emulation approaches offer a flexible way to mimic the properties of a variety of networks. While there are several centralized and distributed emulation tools available that can mimic the behavior of point-to-point links, shared media communication can only be emulated by totally centralized tools so far. To permit the emulation of large-scale mixed network scenarios, the emulation of shared media networks has to be performed in a distributed way also. In this paper, we introduce several strategies to emulate shared media networks in a distributed fashion. For one promising approach, the distributed emulation of carrier sensing, we present a prototype implementation. Measurements show the applicability and limitations of our solution.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-12&engl=0}
}
@inproceedings {INPROC-2003-11,
   author = {Christian Becker and Gregor Schiele},
   title = {{Middleware and Application Adaptation Requirements and their Support in Pervasive Computing}},
   booktitle = {Proceedings of the 23rd International Conference on Distributed Computing Systems Workshops (ICDCS 2003), 3rd International Workshop on Distributed Auto-adaptive and Reconfigurable Systems (DARES), Providence, USA, May 19-22},
   address = {Los Alamitos},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {98--103},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2003},
   isbn = {0-7695-1921-0},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-11/INPROC-2003-11.pdf},
   contact = {Email an christian.becker@informatik.uni-stuttgart.de oder gregor.schiele@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Pervasive computing environments are characterized by an additional heterogeneity compared to existing computing infrastructures. Devices ranging from small embedded systems to full-fledged computers are connected via spontaneously formed networks. In this paper we analyze requirements of applications and system software to cope with the dynamically changing execution environment. Based on our micro-broker-based middleware BASE a component framework for pervasive computing supporting application adaptation is proposed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-11&engl=0}
}
@inproceedings {INPROC-2003-10,
   author = {Michael Kinateder and Kurt Rothermel},
   title = {{Architecture and Algorithms for a Distributed Reputation System}},
   booktitle = {Proceedings of the First International Conference on Trust Management: iTrust'03; Heraklion, Crete, Greece, May 28-30, 2003},
   editor = {Paddy Nixon and Sotirios Terzis},
   address = {Heidelberg},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {2692},
   pages = {1--16},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2003},
   isbn = {3-540-40224-1},
   keywords = {trust; trust management; reputation; recommendation; distributed; peer-to-peer},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.3 Information Search and Retrieval,     H.3.4 Information Storage and Retrieval Systems and Software,     H.3.5 Online Information Services,     H.4.2 Information Systems Applications Types of Systems,     I.2.4 Knowledge Representation Formalisms and Methods,     I.2.11 Distributed Artificial Intelligence,     J.4 Social and Behavioral Sciences},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-10/INPROC-2003-10.pdf,     http://www.springerlink.com/link.asp?id=1e11b5pcvww3qvuf,     http://unitec.informatik.uni-stuttgart.de},
   contact = {Michael Kinateder kinateder@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Trust is an essential component of successful interactions in social life as well as in business relationships. In this paper we propose a system that closely reflects real-world trust building in an online environment. We describe the models used to represent trust in entities in various categories, algorithms to calculate and update trust based on experiences of entities with each other and the agent interactions necessary for finding and exchanging trust information.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-10&engl=0}
}
@inproceedings {INPROC-2003-09,
   author = {Martin Bauer and Christian Becker and J{\"o}rg H{\"a}hner and Gregor Schiele},
   title = {{ContextCube - Providing Context Information Ubiquitously}},
   booktitle = {Proceedings of the 23rd International Conference on Distributed Computing Systems Workshops (ICDCS 2003)},
   address = {Los Alamitos},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {308--313},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2003},
   isbn = {0-7695-1921-0},
   language = {Englisch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-09/INPROC-2003-09.pdf,     http://www.nexus.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Sensing the state of the environment is an important source for context-aware applications. Several approaches exist to provide sensor information to mobile application nodes. As the extreme cases we have pure infrastructures and pure ad hoc networks. In order to allow sensor platforms to serve both of these approaches, we have designed a universal sensor platform and integrated it into an infrastructure-based approach as well as into ad hoc networks. In this paper we discuss the requirements on such a platform, the design, and the experiences.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-09&engl=0}
}
@inproceedings {INPROC-2003-08,
   author = {Jing Tian and Luca Coletti},
   title = {{Routing approach in CarTALK 2000 project}},
   booktitle = {Proceedings of the IST Mobile \& Wireless Communications Summit 2003. Vol. 2},
   address = {Aveiro - Portugal},
   publisher = {Instituto de Telecomunica{\,c}{\~o}es (IT)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {473--477},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2003},
   keywords = {mobile ad hoc routing},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-08/INPROC-2003-08.pdf},
   contact = {jing.tian@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The CarTALK 2000 project aims at the development of new driver assistance systems that are based upon inter-vehicle communication. To this purpose, a mobile ad hoc network (MANET) consisting of vehicles will be developed as the communication platform to support co-operative driver assistance applications. Routing in such a vehicular MANET faces a number of new challenges, in particular due to the extremely dynamic network topology and a large variable number of mobile nodes. Therefore, an efficient and scalable ad hoc routing mechanism is crucial for the performance of the CarTALK 2000 communication system. After analyzing the system characteristics and requirements, this paper introduces a spatially aware routing protocol and a distributed location service. The key of Spatially Aware Routing is to improve position-based routing performance by integrating spatial environment information into routing, such as the underlying road topology.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-08&engl=0}
}
@inproceedings {INPROC-2003-07,
   author = {Kurt Rothermel and Martin Bauer and Christian Becker},
   title = {{Digitale Weltmodelle - Grundlage kontextbezogener Systeme}},
   booktitle = {Total vernetzt - Szenarien einer informatisierten Welt},
   editor = {Friedemann Mattern},
   address = {Berlin, Heiderlberg, New York},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Xpert.press},
   pages = {123--141},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2003},
   isbn = {3-540-0023-8},
   keywords = {Kontext; kontextbezogene Systeme; Ubiquitous Computing; Nexus},
   language = {Deutsch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://www.nexus.uni-stuttgart.de},
   contact = {E-Mail: Kurt.Rothermel@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Die rasant fortschreitende Entwicklung von Sensorsystemen und drahtloser Kommunikation f{\"u}hrt zu multifunktionalen mobilen Endger{\"a}ten, die in der Lage sind, Kontextinformation zu erfassen, zu verarbeiten und zu kommunizieren. Durch die extreme Miniaturisierung eingebetteter Systeme entstehen au{\ss}erdem ``intelligente'' Alltagsgegenst{\"a}nde, die in Netzwerke eingebunden sind und {\"u}ber sensorische F{\"a}higkeiten verf{\"u}gen. Vor dem Hintergrund dieser Entwicklungen ist es absehbar, dass in wenigen Jahren Milliarden von Sensoren existieren werden, die kontinuierlich den Zustand der Realwelt erfassen und kommunizieren. F{\"u}hrt man die sensorisch gewonnen Informationen in einem r{\"a}umlichen Modell zusammen, so entsteht ein digitales Abbild der Realwelt, also ein digitales Weltmodell, das analog zum heutigen Web einen globalen Informationsraum darstellt. Das digitale Weltmodell kann Grundlage sein f{\"u}r ein breites Spektrum kontextbezogener Anwendungen, deren Kontext prinzipiell keinen r{\"a}umlichen Beschr{\"a}nkungen unterworfen ist. In diesem Beitrag wird der Begriff der kontextbezogene Anwendungen erl{\"a}utert und Anwendungen dieser Art am Beispiel existierender Systeme beschrieben und klassifiziert. Au{\ss}erdem wird die Vision, Kontextinformationen in Form digitaler Weltmodelle zu verwalten, dargelegt und motiviert. Schlie{\ss}lich werden die sich aus dieser Vision ergebenden wissenschaftlichen Fragestellungen diskutiert.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-07&engl=0}
}
@inproceedings {INPROC-2003-06,
   author = {J{\"o}rg H{\"a}hner and Christian Becker and Kurt Rothermel},
   title = {{A Protocol for Data Dissemination in Frequently Partitioned Mobile Ad Hoc Networks}},
   booktitle = {Proceedings of the Eighth IEEE Symposium on Computers and Communications (ISCC 2003). Vol. I},
   editor = {Ahmed Tantawy and Kemal Inan},
   address = {Los Alamitos},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {633--640},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2003},
   isbn = {0-7695-1961-X},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2003-06/INPROC-2003-06.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Distribution of data in mobile ad hoc networks is challenged when the mobility of nodes leads to frequent topology changes. Existing approaches so far address either the network partitioning problem or are capable of handling large amounts of data, but not both at the same time. In this paper a novel approach is presented which is based on a negotiation scheme enhanced by an adaptive repetition strategy. Different strategies for the selection of repeated data are presented and evaluated. Simulation results show a reduction of data transfer volume compared to hyper-flooding by 30 to 40\% even in the presence of frequent network partitions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-06&engl=0}
}
@inproceedings {INPROC-2003-05,
   author = {Cora Burger and Matthias Papesch},
   title = {{Eine interaktive und kollaborative Selbstlernumgebung f{\"u}r den Bereich der Sicherheitsprotokolle}},
   booktitle = {Tagungsband der 1. e-Learning Fachtagung Informatik der Gesellschaft f{\"u}r Informatik e.V., DeLFI 2003},
   editor = {Sabine Rathmayer Arndt Bode},
   publisher = {GI Edition „Lecture Notes in Informatics“},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2003},
   keywords = {E-Learning; Security Protocols; Validation},
   language = {Deutsch},
   cr-category = {D.2.4 Software Engineering Software/Program Verification,     I.6.7 Simulation Support Systems,     K.3.1 Computer Uses in Education},
   ee = {http://www.informatik.uni-stuttgart.de/ipvr/vs/de/projects/index.html#ito,     http://www.delfi2003.de},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Im Bereich Verteilter Systeme und Rechnernetze spielen Sicherheitsprotokolle zum Schutz von Identit{\"a}t und anderweitigen Ressourcen einzelner Personen eine wichtige Rolle. Um die Verst{\"a}ndlichkeit dieser komplexen Materie in der Lehre zu erh{\"o}hen und f{\"u}r dieses Gebiet ein von Ort und Zeit unabh{\"a}ngiges Lernen zu erm{\"o}glichen, entstand eine speziell darauf ausgelegte Selbstlernumgebung. Sie verbindet vielf{\"a}ltige Funktionen f{\"u}r ein exploratives Vorgehen sowie automatisiert auswertbare Selbsttests zur Lernkontrolle mit der M{\"o}glichkeit der gemeinsamen Erarbeitung von Inhalten im Lernteam.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2003-05&engl=0}
}
@inproceedings {INPROC-2002-30,
   author = {Alexander Leonhardi and Kurt Rothermel},
   title = {{Architecture of a Large-scale Location Service}},
   booktitle = {Short Paper in Proceedings of the 22nd Conference on Distributed Computing Systems : ICDCS 2002; Vienna, Austria, July 2002},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {465--466},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2002},
   keywords = {Location Service; Nexus},
   language = {Englisch},
   cr-category = {H.0 Information Systems General,     C.2.4 Distributed Systems},
   ee = {http://csdl.computer.org/comp/proceedings/icdcs/2002/1585/00/15850465.pdf,     http://www.nexus.uni-stuttgart.de},
   contact = {Alexander.Leonhardi@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Location-aware services are a promising way of exploiting the special possibilities created by ubiquitous mobile devices and wireless communication. Advanced locationaware applications will require highly accurate information about the geographic location of mobile objects and functionality that goes beyond simply querying the user's position, for example determining all mobile objects inside a certain geographic area. In this paper, we propose a generic large-scale location service, which has been designed with the goal of managing the highly dynamic location information for a large number of mobile objects, thus providing a common infrastructure that can be employed by location-aware applications. We propose a hierarchical distributed architecture, which can efficiently process these queries in a scalable way. To be able to deal with the frequent updates and queries resulting from highly dynamic location information, we propose a data storage component, which makes use of a main memory database.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-30&engl=0}
}
@inproceedings {INPROC-2002-27,
   author = {Alexander Leonhardi and Christian Nicu and Kurt Rothermel},
   title = {{A Map-based Dead-reckoning Protocol for Updating Location Information}},
   booktitle = {Proceedings of the 2nd International Workshop on Parallel and Distributed Computing Issues in Wireless Networks and Mobile Computing (IPDPSWPIM 2002)},
   address = {Fort Lauderdale, FL, USA},
   publisher = {k.A.},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2002},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {www.nexus.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {k.A.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-27&engl=0}
}
@inproceedings {INPROC-2002-23,
   author = {Abdelmajid Khelil and Christian Becker and Jing Tian and Kurt Rothermel},
   title = {{An Epidemic Model for Information Diffusion in MANETs}},
   booktitle = {Proceedings of the 5th International Workshop on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM'02) at MobiCom 2002},
   editor = {Teresa Dahlberg and Michela Meo and Albert Zomaya},
   address = {Atlanta, Georgia, USA},
   publisher = {ACM PRESS},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {ACM MSWiM Proceedings},
   pages = {54--60},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2002},
   isbn = {1-58113-610-2},
   keywords = {Algorithms; Performance; Reliability; MANET; analytical modeling; adaptive information diffusion},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols,     I.6.5 Model Development},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-23/INPROC-2002-23.pdf,     http://canu.informatik.uni-stuttgart.de/},
   contact = {University of Stuttgart / IPVS Breitwiesenstr. 20-22 70565 Stuttgart, Germany +49 711 7816 {251, 357, 228, 434} {khelil, becker, tian, rothermel}@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Choosing appropriate information dissemination strategies is crucial in mobile ad hoc networks (MANET) due to the frequent topology changes. Flooding-based approaches like diffusion have a strong similarity with epidemic spreading of diseases. Applying epidemiological models to information diffusion allows the evaluation of such strategies depending on the MANET characteristics, e.g. the node density. In order to choose appropriate strategies at run time, the model should be easily evaluated. In this paper, an epidemic model is developed for a simple information diffusion algorithm based on simulation results. We analytically investigate the impact of node density on information diffusion. The analytical model allows the evaluation at runtime, even on devices with restricted resources, and thus enables mobile nodes to dynamically adapt their diffusion strategies depending on the local node density.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-23&engl=0}
}
@inproceedings {INPROC-2002-22,
   author = {Christian Becker and Martin Bauer and J{\"o}rg H{\"a}hner},
   title = {{Usenet-on-the-fly - Supporting Locality of Information in Spontaneous Networking Entironments}},
   booktitle = {Workshop on Ad Hoc Communications and Collaboration in Ubiquitous Computing Envirnments},
   editor = {Ramiro Liscano and Gerd Kortuem},
   publisher = {n/a},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--1},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2002},
   language = {Englisch},
   cr-category = {H.4.3 Information Systems Applications Communications Applications,     H.5.3 Group and Organization Interfaces},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-22/INPROC-2002-22.pdf},
   contact = {christian.becker@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {People on the move are typically interested in information with respect to their proximity. Location-based services in general supply users with information about their proximity typically relying on an infrastructure storing the information and tracking the mobile objects, i.e. users. In this paper we present an approach for spontaneous, i.e. ad hoc, networks inspired by the Usenet. Information is exchanged using a peer-to-peer synchronization mechanism. The information is made available through channels grouping related information. The information propagation is solely based on spontaneously connected devices not requiring any infrastructure. Our prototype implementation shows the technical feasibility of our approach, whereas simulation results show the applicability of information diffusion in outdoor scenarios with a realistic number of nodes, covering a city center.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-22&engl=0}
}
@inproceedings {INPROC-2002-21,
   author = {Daniel Herrscher and Kurt Rothermel},
   title = {{A Dynamic Network Scenario Emulation Tool}},
   booktitle = {Proceedings of the 11th International Conference on Computer Communications and Networks (ICCCN 2002), Miami (FL), Oct 14-16, 2002},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {262--267},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2002},
   isbn = {0-7803-7553-X},
   keywords = {Network Emulation; Network Scenario; Emulation Tool},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.2 Network Protocols},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-21/INPROC-2002-21.pdf},
   contact = {herrscher@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Comparative performance measurements of distributed applications and network protocols require the availability of appropriate network environments. Network emulation approaches offer a flexible way to mimic the properties of a variety of networks. Existing emulation tools work either with centralized real-time simulation components, limiting the scenario size and maximum traffic, or focus on the emulation of some network properties at a single point. We propose a tool for the realistic emulation of network links, and show how several emulated links can be combined to reproduce a comprehensive network model. In addition to that, the model can include changing network properties, e.g. emerging from mobile communication partners. This facilitates the distributed emulation of a comprehensive, dynamic network scenario to support repeatable performance measurements.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-21&engl=0}
}
@inproceedings {INPROC-2002-20,
   author = {Detlef Bosau and Cora Burger and Arno Wacker and Martin Pfletschinger},
   title = {{Context-Sensitive Interaction Support during Augmented Lectures}},
   booktitle = {Proceedings of the 7th Cabernet Radicals Workshop},
   editor = {Joe Finney and Mads Haahr and Alberto Montresor},
   address = {Bertinoro (Forly, Italy)},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2002},
   keywords = {e-learning; Application sharing; teaching; mobile computing},
   language = {Englisch},
   cr-category = {H.4.3 Information Systems Applications Communications Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-20/INPROC-2002-20.pdf,     http://www.newcastle.research.ec.org/cabernet/,     http://www.informatik.uni-stuttgart.de/ipvr/vs/en/projects/NUSS/},
   contact = {Send an E-Mail to Arno.Wacker@informatik.uni-stuttgart.de or phone +49-711-7816-236},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {With mobile devices and wireless networks, new possibilities evolve to improve the interaction between teacher and students in class. The paper introduces the idea of DONUT, a Distributed annOtation tool for Notebook University Teachware, which is going to be developed within the NUSS (Notebook University Stuttgart) project being funded by the German Ministry for Education and Research. DONUT is integrated into an existing framework for application sharing. It is based on defining and making use of semantic relationships between presented teaching material and contributions of students. Hence, automatic categorization of contributions becomes available in advance. This supports the teacher's decision, whether to integrate contributions into the lecture or postpone them. Especially, a lot of questions regarding the same topic can indicate problems in understanding on the side of students quite well.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-20&engl=0}
}
@inproceedings {INPROC-2002-19,
   author = {Martin Bauer and Kurt Rothermel},
   title = {{Towards the Observation of Spatial Events in Distributed Location-Aware Systems}},
   booktitle = {Proceedings of the 22nd International Conference on Distributed Computing Systems Workshops},
   editor = {Roland Wagner},
   address = {Los Alamitos, California},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {581--582},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2002},
   isbn = {0-7695-1588-6},
   keywords = {event; event observation; location awareness; Nexus},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {http://www.computer.org/proceedings/icdcsw/1588/15880581.pdf,     http://www.nexus.uni-stuttgart.de},
   contact = {Martin Bauer Martin.Bauer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In this paper, the event concept is applied to support the interaction between mobile users and distributed location-aware systems. Taking a number of examples, the components of an event specification language are derived that can be used beyond the domain of location-aware systems.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-19&engl=0}
}
@inproceedings {INPROC-2002-16,
   author = {Daniel Herrscher and Alexander Leonhardi and Kurt Rothermel},
   title = {{Modeling Computer Networks for Emulation}},
   booktitle = {Proceedings of the 2002 International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA'02), Las Vegas},
   publisher = {CSREA Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {1725--1731},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2002},
   keywords = {Network Emulation; Modeling Language; Network Topologies},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.5 Local and Wide-Area Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-16/INPROC-2002-16.pdf},
   contact = {herrscher@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {The Network Emulation Testbed project provides a configurable network environment for the performance analysis of distributed applications and protocols. An emulation scenario consists of a network topology, link parameters, and dynamic change models. In order to set up a scenario automatically, it has to be modeled in an appropriate description language. In this paper, we analyze the requirements for an emulation scenario description language and propose a possible solution.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-16&engl=0}
}
@inproceedings {INPROC-2002-15,
   author = {Xuejun Chen},
   title = {{Dynamic Reconfiguration of a Component-Based Software System for Vehicles}},
   booktitle = {Proceeding of the 15th IFAC World Congress on Automatic Control},
   address = {Oxford, UK},
   publisher = {Elsevier Science Ltd.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {1--1},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2002},
   keywords = {Mobile Application; Dynamic Reconfiguration; Distributed System; Update Strategy; Component Deployment Strategy},
   language = {Englisch},
   cr-category = {D.2 Software Engineering},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {The component system information and management architecture is a component architecture to build the application software which is used in modern vehicles. The components are distributed in the system: the individual components are mainly located in different computers in vehicles, while the rest runs on computers in the infrastructure. The components can be dynamically loaded to different places of the component system, executed, removed and updated at runtime. In this article, we describe dynamic reconfiguration of a software component system for vehicles. Furthermore, we propose update strategies for updating components and component deployment strategies for optimizing the distributed system. By the use of dynamic reconfiguration, the flexibility and adaptability of the component based distributed system in vehicles are enhanced. In addition, the dynamic reconfiguration can improve the performance of the component system and reduce the costs of communication between a vehicle and the infrastructure.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-15&engl=0}
}
@inproceedings {INPROC-2002-14,
   author = {Xuejun Chen and Martin Simons},
   title = {{A Component Framework for Dynamic Reconfiguration of Distributed Systems}},
   booktitle = {Proceeding of the First International IFIP/ACM Working Conference on Component Deployment (CD 2002)},
   publisher = {Springer Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Lecture Notes in Computer Science},
   pages = {1--1},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2002},
   language = {Englisch},
   cr-category = {D.2 Software Engineering},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {The growing popularity of wired and wireless Internet requires distributed systems to be more flexible, adaptive and easily extendable. Dynamic reconfiguration of distributed component-based systems is one possible solution to meet these demands. However, current component frameworks that support dynamic reconfiguration either place the burden of preparing a component for reconfiguration completely on the component's developer or impose strong restrictions on the component model and the communication mechanisms. We investigate a middle ground between these two extremes and propose a component framework that supports a framework guided reconfiguration and places minimal burden on the component's developer. This component framework offers mechanisms to analyze and treat the interactions between the target component and other components during a dynamic reconfiguration.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-14&engl=0}
}
@inproceedings {INPROC-2002-13,
   author = {Xuejun Chen},
   title = {{Extending RMI to Support Dynamic Reconfiguration of Distributed Systems}},
   booktitle = {Proceeding of the 22nd International Conference on Distributed Computing Systems (ICDCS 2002)},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {1--1},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2002},
   keywords = {Java RMI; Middleware; Dynamic Reconfiguration; Mobile Object; Distributed Systems},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks,     D.1 Programming Techniques},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {By the use of the ability of dynamic reconfiguration, the flexibility, adaptability, and extensibility of distributed systems are enhanced. How to treat interactions among components during a dynamic reconfiguration is still one of the most crucial problems in this research area. This challenge should be met by middleware design and development. However, the current standard middleware offers little support for dynamic reconfiguration of distributed systems. In this paper, we describe an extended Java RMI that supports efficiently dynamic reconfiguration of distributed systems. This extended Java RMI can automatically monitor and manipulate invocations between components during a dynamic reconfiguration. Moreover, the extended Java RMI can automatically switch invocations from remote to local and vice versa.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-13&engl=0}
}
@inproceedings {INPROC-2002-11,
   author = {Uwe Kubach and Kurt Rothermel},
   title = {{Estimating the Benefit of Location-Awareness for Mobile Data Management Mechanisms}},
   booktitle = {Proceedings of the International Conference on Pervasive Computing 2002},
   address = {Heidelberg},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {1--14},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2002},
   keywords = {location awareness; mobile data management; evaluation},
   language = {Englisch},
   cr-category = {H.2 Database Management},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-11/INPROC-2002-11.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {With the increasing popularity of mobile computing devices, the need to access information in mobile environments has also grown rapidly. In order to support such mobile information accesses, location-based services and mobile information systems often rely on location-aware data management mechanisms like location-aware caching, data dissemination or prefetching. As we explain in this paper, the location-awareness of such mechanisms is only useful, if the accessed information is location-dependent, i.e. if the probability with that a certain information object is accessed depends on the user’s location. Although the location-dependency of the accessed information is crucial for the efficiency of location-aware data management mechanisms and the benefit they can get out of their location-awareness, no metric to measure the location-dependency of information has been proposed so far. In this paper, we describe such a metric together with a second one for a further important characteristic of mobile information accesses, the so-called focus.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-11&engl=0}
}
@inproceedings {INPROC-2002-10,
   author = {Jing Tian and J{\"o}rg H{\"a}hner and Christian Becker and Illya Stepanov and Kurt Rothermel},
   title = {{Graph-Based Mobility Model for Mobile Ad Hoc Network Simulation}},
   booktitle = {Proceedings of the 35th Annual Simulation Symposium: San Diego, California, April 14-18, 2002},
   editor = {IEEE Computer Society Press},
   address = {Washington, Brussels, Tokyo},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {337--345},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2002},
   isbn = {0-7695-1552-5},
   keywords = {Mobility Model; Mobile Ad Hoc Network; Simulation; Spatial Model},
   language = {Englisch},
   cr-category = {I.6 Simulation and Modeling,     G.3 Probability and Statistics},
   contact = {canu@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Imagine a world where people constantly try to pass through walls and cars suddenly leave the roads and drive into rivers. Although this is unrealistic, most simulations for mobile ad hoc networks so far are based on the so called ``random walk'' of mobile objects, which are not constrained by their surrounding spatial environments. In this paper we propose a novel graph-based mobility model, which provides a more realistic movement than the random walk model by reflecting the spatial constraints in the real world. We analyzed three commonly used ad hoc network routing protocols, DSDV, DSR and AODV with both a random walk-based and our graph-based mobility model. Our simulation results show that the spatial constraints have a strong impact on the performance of ad hoc routing protocols.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-10&engl=0}
}
@inproceedings {INPROC-2002-09,
   author = {Joachim Jordan and Ulrich Kleinhans and Ottokar Kulendik and J{\"u}rgen Porscha and Alwin Pross and Reiner Siebert},
   title = {{Transparent and Flexible Cross-Organizational Workflows for Engineering Cooperations in Vehicle Development}},
   booktitle = {PDT Europe 2002},
   address = {Torino, Italy},
   publisher = {Quality Marketing Services, Sandhurst, UK},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {101--108},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2002},
   isbn = {1 901782 06 9},
   keywords = {cross-organizational workflow management; engineering},
   language = {Englisch},
   cr-category = {H.5.3 Group and Organization Interfaces,     C.2.4 Distributed Systems,     H.4.1 Office Automation,     J.1 Administration Data Processing,     J.2 Physical Sciences and Engineering},
   contact = {ottokar.kulendik@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Engineering cooperations for vehicle development have proven to be successful not just to extend capacities but to profit from each other's specific know-how. Workflow management bears the potential to reduce cooperation barriers and costs. Within a cooperation project between DaimlerChrysler AG and EDAG, application scenarios have been defined to identify goals and benefits, to analyse important requirements, and to develop an IT solution concept, together with the University of Stuttgart. Manufacturer and supplier both would profit from 1.) manageable automation of cross-organizational workflows, 2.) transparency of their partner's processes, 3.) flexibility of specifying own workflows autonomously, and 4.) integration of heterogeneous workflow management systems. For research, this field of application is challenging because existing approaches so far do not seem to be sufficient. We describe a relevant scenario from an engineering cooperation project in detail. The resulting requirements do not only occur across companies, but in general even inside a single company. An appropriate solution should be able to deal with multiple interactions and some more complex dependencies between different workflows. It should be possible to make relevant data visible but keep irrelevant information private, and to support a late evolution of partner's workflows. To address those requirements appropriately, our approach minimizes the specification agreed between the partners, therefore allowing to specify the associated partner's workflows in a decentralized, delayed manner. External workflow schemata can be used to give partners a view on each other's workflow. We use a peer-to-peer architecture in which complex dependencies between workflows are mapped onto simpler messages.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-09&engl=0}
}
@inproceedings {INPROC-2002-08,
   author = {Peter Coschurba and Kurt Rothermel and Frank D{\"u}rr},
   title = {{A fine grained addressing concept for GeoCast}},
   booktitle = {Trends in Network and Pervasive Computing -- ARCS 2002 (Proceedings of the International Conference on Architecture of Computing Systems 2002)},
   editor = {Hartmut Schmeck and Theo Unger and Lars Wolf},
   address = {Karlsruhe, Germany},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Lecture Notes in Computer Science},
   volume = {2299},
   pages = {101--113},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2002},
   isbn = {3-540-43409-7},
   keywords = {routing; location-based services; geographic communication; GeoCast},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-08/INPROC-2002-08.pdf,     http://www.springerlink.com/content/8hcep0e11k61tx53/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {GeoCast provides the functionality of sending messages to everyone in a specific area. So far, only the addressing of larger two-dimensional areas was possible. For the use in an urban environment it is crucial that small and three-dimensional areas can be addressed. For example, GeoCast can then be used to send lecture notes to all in a classroom. In this paper we describe a fine-grained addressing concept for GeoCast that supports such areas. In addition we present an architecture that allows the use of that addressing concept together with the GeoRouting-approach developed by Navas and Imielinski. We also present some modifications necessary to enhance the scalability of GeoCast.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-08&engl=0}
}
@inproceedings {INPROC-2002-06,
   author = {Cora Burger and Stella Papakosta and Eric Bullinger and Thomas Wagner},
   title = {{Investigation of application sharing systems for teaching purposes in engineering disciplines}},
   booktitle = {4th International Conference on New Educational Environment 2002},
   publisher = {EduSwiss},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2002},
   keywords = {Application Sharing; Wireless Campus; Awareness},
   language = {Englisch},
   cr-category = {H.4.3 Information Systems Applications Communications Applications},
   ee = {http://www.informatik.uni-stuttgart.de/ipvr/vs/projekte/Festival/sascia.html,     http://www.eduswiss.ch/4th-conf/default.asp},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {With portable devices and wireless networks, a new potential is arising to improve teaching in collocated, remote and hybrid scenarios. This can be achieved by a suitable mixture of theoretical and practical elements, where students can try out applications by themselves during lectures. Existing systems for application sharing do not cope with the specific requirements of this environment. Hence, the system SASCIA (System architecture supporting cooperative and interactive applications) has been developed and tested successfully.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-06&engl=0}
}
@inproceedings {INPROC-2002-04,
   author = {Cora Burger and Stella Papakosta and Kurt Rothermel},
   title = {{Application sharing in teaching context with wireless networks}},
   booktitle = {Proc. World Congress NETWORKED LEARNING IN A GLOBAL ENVIRONMENT - Challenges and Solutions for Virtual Education},
   publisher = {NAISO (Natural and Artificial Intelligence Systems Organization) The Netherlands},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2002},
   keywords = {Application sharing; teaching},
   language = {Englisch},
   cr-category = {H.4.3 Information Systems Applications Communications Applications},
   ee = {http://www.icsc-naiso.org/conferences/nl2002/,     http://www.informatik.uni-stuttgart.de/ipvr/vs/projekte/Festival/sascia.engl.html},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {The success of teaching is depending on a couple of factors where collaboration among all participants, teachers and students are the most important ones. With mobile devices and wireless networks, new possibilities evolve for improvement. By promoting existing concepts of application sharing systems, the project SASCIA (System architecture supporting cooperative and interactive applications) aims at developing a framework for multiple applications to support teaching in collocated, remote and hybrid scenarios. It provides annotation and recording to support latecomers and further exceptions as well as subsequent replay. Moreover, configurable context awareness among participants as well as floor and consistency control cover a wide spectrum of applications and learning situations. According to first experiments, the prototype is performing well and was readily accepted by students.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-04&engl=0}
}
@inproceedings {INPROC-2002-02,
   author = {Cora Burger and Eric Bullinger and Stella Papakosta and Thomas Wagner},
   title = {{Context awareness for application sharing in teaching environment}},
   booktitle = {International Conference on Advances in Infrastructure for e-Business, e-Education, e-Science, and e-Medicine on the Internet},
   publisher = {Scuola Superiore G. Reiss Romoli},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {00--00},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2002},
   keywords = {Application sharing, context awareness, teaching},
   language = {Englisch},
   cr-category = {H.4.3 Information Systems Applications Communications Applications,     H.5.3 Group and Organization Interfaces,     J.1 Administration Data Processing},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2002-02/INPROC-2002-02.ps,     http://www.ssgrr.it/en/ssgrr2002w/index.htm,     http://www.informatik.uni-stuttgart.de/ipvr/vs/projekte/Festival/sascia.html},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Mobile and ubiquitous computing offer new possibilities to increase the awareness in class and support an active participation of students. To this end, context information is captured and distributed about sessions, participants and those applications that are used during a lecture or encounter among students (e. g. presentations, development and simulation environments, experiments in natural and engineering sciences). The framework of SASCIA (System Architecture Supporting Cooperative and Interactive Applications) cares for appropriate usage of this information to enable new ways of application sharing. First experiments have proofed the usefulness of the system and an acceptable performance.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2002-02&engl=0}
}
@inproceedings {INPROC-2001-50,
   author = {Darko Klinec and Alexander Leonhardi},
   title = {{Positioning and Location Services for Indoor Areas in Nexus}},
   booktitle = {Proceedings of the International Symposium on Indoor Navigation (INDOORNAV 2001)},
   address = {M{\"u}nchen},
   publisher = {k.A.},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2001},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {www.nexus.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Photogrammetrie (ifp)},
   abstract = {k.A.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-50&engl=0}
}
@inproceedings {INPROC-2001-49,
   author = {Xuejun Chen and Matthias St{\"u}mpfle},
   title = {{Dynamic Configuration Management of a Telematics System for Vehicles}},
   booktitle = {Proceeding of the 1st IFAC Conference on Telematics Applications in Automation and Robotics (TA 2001)},
   address = {Oxford, UK},
   publisher = {Elsevier Science Ltd},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {279--284},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   keywords = {Configuration Management; Software Component; Dynamic Reconfiguration; Telematics System},
   language = {Englisch},
   cr-category = {D.2 Software Engineering},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {The Component System Information and Management Architecture is a component architecture to build telematics systems which are used in modern vehicles. The components are distributed in the architecture: the individual components are mainly located in different computers in vehicles, while the rest runs on computers in the infrastructure. The components can be dynamically loaded to different places of a mobile component system, executed, removed and updated at runtime. The dynamic reconfiguration requires an efficient and robust configuration management. This article describes a configuration management which supports a dynamic reconfiguration at runtime for a component system of this kind. The dynamic reconfiguration can improve the performance of the component system and reduce the communication costs between a vehicle and the infrastructure.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-49&engl=0}
}
@inproceedings {INPROC-2001-48,
   author = {Kurt Rothermel and Alexander Leonhardi},
   title = {{Maintaining Worls Models for Context-aware Applications}},
   booktitle = {Proceedings of the 8th International Conference on Advances in Communication and Control (COMCON-8)},
   editor = {William R. Wells},
   address = {New York, Los Angeles},
   publisher = {Optimization Software Inc.},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {235--245},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2001},
   isbn = {0-911575-78-2},
   keywords = {NEXUS; context-aware; location-aware; location service},
   language = {Englisch},
   cr-category = {H.2 Database Management},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2001-48/INPROC-2001-48.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In this paper we describe the architecture and world model of the neXus platform for location- and context-aware applications. An important aspect of the neXus world model is that it also describes highly mobile objects, such as persons or vehicles. Therefore, we look in more detail at the management of location information in the neXus platform and the neXus Location Service, which provides for tracking the location of mobile objects with a high accuracy. In particular, we present a comparison of and simulation results for different protocols that are suitable for the frequent updating of highly accurate location information.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-48&engl=0}
}
@inproceedings {INPROC-2001-47,
   author = {Ottokar Kulendik and Kurt Rothermel and Reiner Siebert},
   title = {{Cross-organizational workflow management - General Approaches and their Suitability for Engineering Processes}},
   booktitle = {Proceedings of the First IFIP-Conference on E-Commerce, E-Business, E-Government : I3E 2001 ; Zuerich, Switzerland, October 3-5, 2001},
   editor = {Beat Schmid and Katarina Stanoevska-Slabeva and Volker Tschammer},
   address = {Zuerich, Switzerland},
   publisher = {Kluwer Academic Publishers},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {143--158},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2001},
   isbn = {0-7923-7529-7},
   keywords = {cross-organizational workflow management; engineering},
   language = {Englisch},
   cr-category = {H.5.3 Group and Organization Interfaces,     C.2.4 Distributed Systems,     H.4.1 Office Automation,     J.1 Administration Data Processing,     J.2 Physical Sciences and Engineering},
   contact = {ottokar.kulendik@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Cross-organizational workflow management deals with the need for transparent and controlled process automation across organizational boundaries. Cooperation between manufacturers and suppliers in the field of engineering requires coupling of parallel workflows of autonomous organization units. So far, several approaches with different architectures exist but they address this field of application differently. This paper presents some requirements of cross-organizational workflow management in the engineering domain by using an application scenario. Existing research approaches are classified distinguishing used specification schemata and expressiveness concerning cross-workflow dependencies. We describe a new approach in a class that matches the presented requirements.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-47&engl=0}
}
@inproceedings {INPROC-2001-46,
   author = {Christian Becker and Gregor Schiele},
   title = {{New mechanisms for routing in ad hoc networks}},
   booktitle = {Proceedings of the Fourth CaberNet Plenary Workshop; Pisa, Italy, October 9-11, 2001.},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2001},
   keywords = {mobile ad hoc routing; model based routing; user profiles},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols},
   contact = {gregor.schiele@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Routing in ad hoc networks is challenged by mobility and dynamics of mobile devices. Hence, classic routing algorithms hardly cope with partitions and constant topology changes in such networks. Existing routing algorithms are based on flooding to explore a location or known node locations. In this paper we present an approach based on additional information available in such networks that will help to reduce the network load without relying on known receiver locations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-46&engl=0}
}
@inproceedings {INPROC-2001-45,
   author = {Christian Maih{\"o}fer and Kurt Rothermel},
   title = {{A Delay Analysis of Tree-based Reliable Multicast Protocols}},
   booktitle = {Proceedings of the International Conference on Computer Communications and Networks (ICCCN 01)},
   editor = {IEEE},
   address = {Scottsdale, Arizona, USA},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {274--281},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2001},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2001-45/INPROC-2001-45.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {We present a comparative delay analysis of tree-based reliable multicast protocols and show the influence of varying sending rates, group sizes, packet loss probabilities and branching factors of the control tree. Besides the average delivery delay we consider the delay to reliably deliver all packets and the round trip delay. The former two examines the delay between generation of a packet at the sender and correct reception at a randomly chosen receiver or all receivers, respectively. The latter is the delay between generation of a packet at the sender and reception of all acknowledgement packets at the sender. Our numerical results show that all tree-based protocols provide low delays and good scalability. From the four considered protocol classes, NAK-based protocols achieve the best scalability but ACK-based protocols achieve the lowest delays.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-45&engl=0}
}
@inproceedings {INPROC-2001-36,
   author = {Martin Bauer and Christian Becker and Kurt Rothermel},
   title = {{Location Models from the Perspective of Context-Aware Applications and Mobile Ad Hoc Networks}},
   booktitle = {Workshop on Location Modeling for Ubiquitous Computing, UbiComp 2001},
   address = {Atlanta},
   publisher = {-},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2001},
   keywords = {location, location-aware, location model, modeling language, Nexus, Canu},
   language = {Englisch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2001-36/INPROC-2001-36.pdf},
   contact = {Martin.Bauer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Location models are crucial to location-aware applications. In this paper we present two approaches for modeling location information in an infrastructure-based and an ad hoc network based application scenario. From these approaches we deduce requirements for a general location modeling language for ubiquitous computing.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-36&engl=0}
}
@inproceedings {INPROC-2001-35,
   author = {S. Papakosta and C. Burger},
   title = {{Generating Interactive Protocol Simulations and Visualizations for Learning Environments}},
   booktitle = {CaberNet: 4th Plenary Workshop. Vol. 2001},
   publisher = {Not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2001},
   keywords = {SPIN; Promela; model checking; simulation; animation},
   language = {Englisch},
   cr-category = {C.2.2 Network Protocols,     I.6 Simulation and Modeling,     K.3 Computers and Education,     H.5.1 Multimedia Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2001-35/INPROC-2001-35.ps,     http://www.informatik.uni-stuttgart.de/ipvr/vs/projekte/HiSAP/hisap.html,     http://iasc88.ias.uni-stuttgart.de/ito/},
   contact = {papakosi@informatik.uni-stuttgart.de caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {This position paper introduces the idea and concept of generating interactive protocol simulations and visualizations for teaching environments in lectures as well as for learning environments over the internet. Since the realisation is based on the SPIN model checker, a short presentation of this verification tool and its language Promela is shortly been given before sketching the generation procedure itself. The architecture presented here is open to further extensions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-35&engl=0}
}
@inproceedings {INPROC-2001-28,
   author = {J{\"u}rgen Hauser and Kurt Rothermel},
   title = {{Specification and Implementation of an Extensible Multimedia System}},
   booktitle = {Tagungsband Kommunikation in Verteilten Systemen (KiVS) 2001},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {216--226},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2001},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {The research project MAVA (Multimedia Document Versatile Architecture) focuses on simplification of specification and dissemination of multimedia documents. The problems discussed and solved by the MAVA approach are observed by using existing authoring systems. Application specific multimedia systems provide fixed concepts for only one application area. Generic systems allow the specification of documents of arbitrary application areas. This leads to complex specifications and the requirement of programming skills for authors. Goal of the MAVA approach is to simplify authoring of multimedia documents in different application areas by an extensible specification language. This allows to add new language elements for particular application areas to simplify authoring. While the extension with new media types is addressed by several approaches the MAVA approach considers also the extension for new particular application areas. Document dissemination plays also an important role. For the presentation of a document basing on arbitrary language extensions also the presentation system itself has to be dynamically extended over the Internet.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-28&engl=0}
}
@inproceedings {INPROC-2001-20,
   author = {Rolf Mecklenburg and Cora Burger and Kurt Rothermel},
   title = {{Visualized Interactive Protocols: A Way to Teach and Test Rules of Computer Communication}},
   booktitle = {Fourth World Conference on Integrated Design \& Process Technology},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2001},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {By understanding protocols in computer communication, different cognition levels are involved. After a mere observation phase of predefined scenarios, interactively modifying parameters and rules to test the resulting behavior are best suited to become acquainted with a protocol. Because of the complexity of protocols, only a few consequences of such modifications can be seen directly. Therefore, support is needed to be able to estimate changes in protocol behavior caused by such modifications. We describe ``HISAP'' (Highly Interactive Simulation of Algorithms and Protocols), whose features enable such a way of training in computer protocols.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-20&engl=0}
}
@inproceedings {INPROC-2001-18,
   author = {Uwe Kubach and Mario Hegele and Kurt Rothermel},
   title = {{A Simulation Framework for Mobile, Location-Dependent Information Access}},
   booktitle = {Proceedings of the 6th IEEE Symposium on Computers and Communications (ISCC 2001)},
   address = {Hammamet, Tunesia},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {506--511},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {With the increasing pervasiveness of mobile computing devices, the need to access information in mobile environments has grown rapidly. Consequently, many mechanisms, e.g. broadcast dissemination, hoarding, or specialized caching mechanisms have been developed to overcome the disadvantages of wireless communication systems, which are usually used to access the information. To evaluate such mechanisms a simulation tool is needed that simulates both the users' mobility and their information access patterns. Since most existing user models either model only the mobility or the information access, we developed a new model that covers both aspects. Based on this model, we realized a flexible framework that allows to simulate all aspects of a mobile information access.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-18&engl=0}
}
@inproceedings {INPROC-2001-16,
   author = {Peter Coschurba},
   title = {{Ein {\"U}berblick {\"u}ber GeoCast}},
   booktitle = {Praxis der Informationsverarbeitung (PIK)},
   address = {M{\"u}nchen},
   publisher = {K.G. Saur Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   volume = {24},
   number = {2001},
   pages = {63--66},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2001},
   isbn = {3-598-01236-5},
   keywords = {GeoCast},
   language = {Deutsch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     C.2.2 Network Protocols},
   contact = {Peter.Coschurba@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Die vorhandenen Internetprotokolle erlauben das effiziente Versenden von Nachrichten an mehrere Empfaenger. Allerdings muessen die Empfaenger den Empfangswunsch explizit erkl{\"a}ren. F{\"u}r viele Anwendungen ist es w{\"u}nschenswert, eine Nachricht an alle Empf{\"a}nger in einem bestimmten geographischen Gebiet zu senden. Dieses wird durch GeoCast realisiert. Bei GeoCast spezifiziert der Sender ein Gebiet und alle potentiellen Empfaenger in diesem Gebiet erhalten diese Nachricht. In desem Artikel wird betrachtet, was m{\"o}gliche Anwendungen fuer diese Technik sind. Zudem wird der derzeitige Stand der Technik im Bereich GeoCast erlaeutert.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-16&engl=0}
}
@inproceedings {INPROC-2001-13,
   author = {U. Kubach and K. Rothermel},
   title = {{A Map-Based Hoarding Mechanism for Location-Dependent Information}},
   booktitle = {Proceedings of the 2nd International Conference on Mobile Data Management (MDM 2001)},
   address = {Hong Kong, China},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {145--157},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2001},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In mobile environments, information systems are often accessed through wireless WANs. Thus the users often have to cope with difficulties such as low bandwidth, high delay, and frequent disconnections. Hoarding is an efficient method to overcome these difficulties. The idea is to transfer information, which is probably needed by the user in the near future, in advance, so that it is already stored on the user's mobile device when it is actually accessed. In this paper, we present a location-aware hoarding mechanism that is based on the use of wireless LANs, so-called info-stations. Due to its flexibility, we claim that our mechanism can be applied in any location-dependent information system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-13&engl=0}
}
@inproceedings {INPROC-2001-12,
   author = {U. Kubach and K. Rothermel},
   title = {{Exploiting Location Information for Infostation-Based Hoarding}},
   booktitle = {Proceedings of the 7th ACM SIGMOBILE Annual International Conference on Mobile Computing and Networking (MobiCom 2001)},
   address = {Rome, Italy},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {15--27},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   keywords = {Mobile data management, mobile information access, infostations, hoarding, location-awareness},
   language = {Englisch},
   cr-category = {C.2.0 Computer-Communication Networks, General,     C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   contact = {Uwe.Kubach@informatik.uni-stuttgart.de Kurt.Rothermel@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {With the increasing popularity of mobile computing devices, the need to access information in mobile environments has grown rapidly. Since the information has to be accessed over wireless networks, mobile information systems often have to deal with problems like low bandwidth, high delay, and frequent disconnections. Information hoarding is a method that tries to overcome these problems by transferring information, which the user will probably need, in advance. The hoarding mechanism that we describe in this paper exploits the location dependence of the information access, which is often found in mobile information systems. Our simulation results show that it is beneficial to do so and that we achieve higher hit ratios than with a caching mechanism.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-12&engl=0}
}
@inproceedings {INPROC-2001-11,
   author = {J.-U. Kloecking and C. Maih{\"o}fer and K. Rothermel},
   title = {{Reducing Multicast Inter-Receiver Delay Jitter - A Server Based Approach}},
   booktitle = {Proceedings of the IEEE International Conference on Networking (ICN 2001)},
   address = {Colmar, France},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-11&engl=0}
}
@inproceedings {INPROC-2001-10,
   author = {J{\"u}rgen Klarmann},
   title = {{Using Conceptual Graphs for Organization Modelling in Workflow Management Systems}},
   booktitle = {Proceedings of the Conference Professionelles Wissensmanagement (WM 2001)},
   address = {Baden-Baden, Germany},
   publisher = {Shaker-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {19--23},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2001},
   isbn = {3-8265-8611-5},
   keywords = {Workflow Management, Conceptual Graphs, Organization Modeling, Flexibility},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   contact = {juergen.klarmann@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Workflow management systems reflect business structures in a separate organizational model and a process model because these models describe different aspects of business structures. The organizational model comprises members of an organization and organizational relationships (organizational structure) whereas the process model contains information about the tasks and their dependencies (process structure). Linking both of these models becomes more and more problematic because organizational models change much more nowadays than they have before and so lead to orphaned references in the process model. Moreover, organizational models should be unknown during process modeling, and equivalent process models should run with different organizational structures. For this, we introduce conceptual graphs for specifying organizational structures in the organizational model and for specifying potential task holders in the process model. We cover organizational knowledge and retrieve it at runtime exploiting the benefits of these knowledge representation technique. With this, it is possible to renounce name referencing and gain more degrees of freedom for the linking process},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-10&engl=0}
}
@inproceedings {INPROC-2001-09,
   author = {J{\"u}rgen Klarmann},
   title = {{A Comprehensive Support for Changes in Organizational Models of Workflow Management Systems}},
   booktitle = {Proceedings of the 4th International Conference on Information Systems Modeling (ISM '01)},
   address = {Hradec nad Moravici, Czech Republic},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {165--172},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {2001},
   keywords = {workflow, organization modeling},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In today's rapidly changing markets, organizations repeatedly change their structures. Existing workflow management systems reflect these structures in a separate organizational model and a process model (workflow model). However, these systems cannot cope with repetitive and frequent structural change of organizational and process structure and thus hamper continuous operation and quick reactions to turbulent markets. Change in the structure of the organizational model can cause orphaned references in the process model which leads to inconsistent workflow specifications. We describe the problem domain of structural change and classify it by eight categories. A powerful organizational meta model is introduced that allows to describe meta information about organizational structures. With this and with an underlying ontology, it enables workflow management systems to efficiently adapt to change. Finally, we show exemplarily how our approach is able to deal with the identified categories of structural change.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-09&engl=0}
}
@inproceedings {INPROC-2001-08,
   author = {Christian Maih{\"o}fer and Kurt Rothermel},
   title = {{Optimal Branching Factor for Tree-Based Reliable Multicast Protocols}},
   booktitle = {Proceedings of the 2001 International International Symposium on Performance Evaluation on computer and Telecommunication Systems (SPECTS)},
   editor = {SCS},
   address = {Orlando, USA},
   publisher = {SCS},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {10--21},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In recent years, a number of reliable multicast protocols on transport layer have been proposed. Previous analysis and simulation studies gave evidence for the superiority of tree-based approaches in terms of throughput and bandwidth requirements. In many tree-based protocols, the nodes of the tree are formed of multicast group members. In this case, the branching factor, i.e.$\backslash$ the maximum number of child nodes is adjustable. In this paper we analyze the influence of the branching factor on a protocol's throughput and bandwidth consumption. This knowledge is important to configure protocols for best performance and to optimize the tree creation process. Our results show that the optimal branching factor depends mainly on the probability for receiving messages from other local groups. If local groups are assigned to a separate multicast address, the optimal branching factor is 2. On the other hand, if TTL scoping is used and therefore the probability for receiving messages from other local groups is greater than zero, larger local groups provide better performance.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-08&engl=0}
}
@inproceedings {INPROC-2001-07,
   author = {Christian Maih{\"o}fer and Kurt Rothermel},
   title = {{A Delay Analysis of Generic Multicast Transport Protocols}},
   booktitle = {Proceedings of the 2001 IEEE International Conference on Multimedia and Expo (ICME2001)},
   editor = {IEEE},
   address = {Tokyo, Japan},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {We present a delay analysis of three generic classes of multicast transport protocols. The first class considered is an unreliable scheme that works without retransmission of messages. This class also includes forward error correction approaches. The second class uses a positive acknowledgment and retransmission scheme to guarantee reliability. Finally, the third class is a hierarchical approach to avoid the well-known ACK implosion problem for large receiver groups. Our results show that only the unreliable and the hierarchical protocol class provide scalability for large receiver groups. For delay sensitive applications we can conclude from the results that in case of low packet loss probabilities, reliable multicast protocols provide low average delays, which are only slightly increased compared to unreliable protocols. However, if we take the maximum delay, the delay is significantly increased.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-07&engl=0}
}
@inproceedings {INPROC-2001-06,
   author = {Christian Maih{\"o}fer and Kurt Rothermel},
   title = {{A Bandwidth Analysis of Tree-based Reliable Multicast Protocols}},
   booktitle = {Proceedings of the 2001 International Symposium on the Convergence of IT and Communications (ITCOM)},
   editor = {Spie},
   address = {Denver, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {354--368},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2001},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2001-06/INPROC-2001-06.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In this paper, an analytical bandwidth evaluation of generic tree-based reliable multicast protocols is presented. Our analysis is based on a realistic system model, including data packet and control packet loss, asynchronous local clocks and imperfect scope-limited local groups. Two of the four considered protocol classes use aggregated acknowledgments (AAKs). With AAKs they are able to provide reliability even in case of node failures. All tree-based protocols provide good scalability for large receiver groups. Relating to protocols with aggregated acknowledgments, the analysis shows only little additional bandwidth overhead and therefore high throughput rates. Finally, we have analyzed the influence of the branching factor on a protocol's performance. Our results show that the optimal branching factor depends mainly on the probability for receiving messages from other local groups. If local groups are assigned to a separate multicast address, the optimal branching factor is 2. On the other hand, if TTL scoping is used as in RMTP or TMTP and therefore the probability for receiving messages from other local groups is greater than zero, larger local groups provide better performance.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-06&engl=0}
}
@inproceedings {INPROC-2001-05,
   author = {Christian Maih{\"o}fer and Kurt Rothermel},
   title = {{A Delay Analysis of Reliable Multicast Protocols}},
   booktitle = {Proceedings of the 2001 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS)},
   editor = {SCS},
   address = {Orlando, USA},
   publisher = {SCS},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {1--9},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2001},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2001-05/INPROC-2001-05.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {We present a delay analysis of one sender- and two receiver-initiated classes of reliable multicast protocols. Besides the average delivery delay we consider the delay to reliably deliver all packets and the round trip delay. The former two examines the delay between generation of a packet at the sender and correct reception at a randomly chosen receiver or all receivers, respectively. The latter is the delay between generation of a packet at the sender and reception of all acknowledgement packets at the sender. Our numerical results show that receiver-initiated protocols provide significantly better scalability for large receiver groups and transmission rates compared to the sender-initiated protocol. However, the delays of the sender-initiated protocol within its scalability range is substantially lower compared to the receiver-initiated protocols. To assess the quality of our analytical model we have compared the analytical results with a SRM-like protocol simulation. We show that the analytical and simulation results are strongly correlated, which demonstrates the appropriateness of our analytical model.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-05&engl=0}
}
@inproceedings {INPROC-2001-04,
   author = {J{\"u}rgen Hauser},
   title = {{A Component-based Extensible Multimedia System}},
   booktitle = {Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA '2001)},
   editor = {H. R. Arabnia},
   address = {Las Vegas, NV, USA},
   publisher = {CSREA Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {1243--1249},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2001},
   isbn = {1-892512-69-6},
   language = {Englisch},
   cr-category = {H Information Systems},
   contact = {juergen.hauser@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-04&engl=0}
}
@inproceedings {INPROC-2001-03,
   author = {J{\"u}rgen Hauser and Kurt Rothermel},
   title = {{Document Specification and Dissemination with an Extensible Multimedia System}},
   booktitle = {Proceedings of the 12th Kommunikation in Verteilten Systemen (KiVS)},
   editor = {Ulrich Killat and Winfried Lamersdorf},
   address = {Hamburg, Germany},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {215--226},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {2001},
   isbn = {3-540-41645-5},
   language = {Englisch},
   cr-category = {H Information Systems},
   contact = {juergen.hauser@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2001-03&engl=0}
}
@inproceedings {INPROC-2000-16,
   author = {Alexander Leonhardi and Martin Bauer},
   title = {{The VIT-System: Experiences with Developing a Location-Aware System for the Internet}},
   booktitle = {Workshop on Infrastructure for Smart Devices, How to Make Ubiquity an Actuality, at the HUC2k, Bristol, Great Britain, 2000.},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {2000},
   language = {Deutsch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-16/INPROC-2000-16.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {A lot of information is interesting in a local context, e.g. the bus schedule of the local bus station or the location and opening hours of the closest supermarket. Therefore, location-aware access to information and services is an important feature of applications for mobile and ubiquitous devices. Most existing location-aware systems have been designed for certain applications, for example office information systems or tourist guides. At the University of Stuttgart we have developed a system for location-aware information access that serves as a platform for different kinds of information systems. Its main objectives were the seamless integration with existing Internet mechanisms and protocols and the intention to make publishing location-aware information as easy as setting up a page on the World Wide Web.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-16&engl=0}
}
@inproceedings {INPROC-2000-15,
   author = {P. Coschurba and U. Kubach and A. Leonhardi},
   title = {{Research Issues in Developing a Platform for Spatial-Aware Applications}},
   booktitle = {Proceedings of the 9th ACM SIGOPS European Workshop},
   address = {Kolding, Denmark},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {153--158},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2000},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-15&engl=0}
}
@inproceedings {INPROC-2000-14,
   author = {Cora Burger},
   title = {{Context Notification in Mobile Environments to find the Right Person in Time}},
   booktitle = {Trends in Distributed Systems: Towards a Universal Service Market - Third International IFIP/GI Working Conference, USM 2000},
   editor = {Claudia Linnhoff--Popien and Heinz--Gerd Hegering},
   address = {Munich, Germany},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {1890},
   pages = {278--283},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2000},
   keywords = {context awareness; trading},
   language = {Englisch},
   cr-category = {H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://Festival.informatik.uni-stuttgart.de/,     http://usm2000.informatik.uni-muenchen.de/index.shtml},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-14&engl=0}
}
@inproceedings {INPROC-2000-12,
   author = {Christian Maih{\"o}fer and Kurt Rothermel and Nicole Mantei},
   title = {{A Throughput Analysis of Reliable Multicast Transport Protocols}},
   booktitle = {Proceedings of the 9th International Conference on Computer Communciations and Networks (IEEE ICCCN 2000)},
   editor = {IEEE},
   address = {Las Vegas, USA},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {250--257},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2000},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-12/INPROC-2000-12.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-12/INPROC-2000-12.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Tree-based reliable multicast protocols are known to provide better scalability than the protocols based on pure sender- and receiver-initiated schemes. However, previous analytical work that has provided these results is based on a system model which assumes reliable control message delivery and synchronized local clocks. These assumptions are questionable simplifications, since they favor protocols using multicasted negative acknowledgments with NAK avoidance scheme. In this paper, we extend previous analysis by taking into account control data loss and asynchronous local clocks. We further analyze a new protocol class with particular importance, the tree-based approach with aggregated acknowledgments. In contrast to other approaches, this class provides reliability not only in case of message loss but also in case of node failures. Our results show that the additional overhead to cope with node failures is very low and therefore acceptable for reliable multicast implementations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-12&engl=0}
}
@inproceedings {INPROC-2000-11,
   author = {Christian Maih{\"o}fer},
   title = {{Improving Multicast ACK Tree Construction with the Token Repository Service}},
   booktitle = {Proceedings of the ICDCS 2000 Workshop on Group Communication},
   editor = {IEEE},
   address = {Taipei, Taiwan},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {57--64},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2000},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-11/INPROC-2000-11.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-11/INPROC-2000-11.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Many new applications like groupware systems, news and file distribution or audio/video systems are based on multicast as a prerequisite for scalability. Many of these applications need the multicast support to be reliable, which is realized in a scalable way by tree based multicast transport protocols, where the receivers are organized in a ACK tree. Tree based approaches raise the problem of setting up and maintaining the ACK tree, which is usually done by variations of the expanding ring search (ERS) approach. In this paper we present an alternative approach for creating ACK trees which is based on the concept of a distributed token repository service. Simulation results show that our approach leads to a lower message overhead than ERS and results in better shaped ACK trees.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-11&engl=0}
}
@inproceedings {INPROC-2000-10,
   author = {Christian Maih{\"o}fer},
   title = {{Scalable and Reliable Multicast ACK Tree Construction wit the Token Repository Service}},
   booktitle = {Proceedings of the 8th IEEE International Conference on Networks (ICON 2000)},
   editor = {IEEE},
   address = {Singapore},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {351--358},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2000},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-10/INPROC-2000-10.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-10/INPROC-2000-10.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Reliable multicast is realized in a scalable way by tree based approaches, where the receivers are organized in an ACK tree. Usually, expanding ring search (ERS) is used to create such ACK trees. However, ERS has some shortcomings like poor scalability, strong dependency on the multicast routing protocol and the need for bidirectional multicast capable networks, which makes it difficult to use ERS as the Internet standard mechanism. In this paper we propose the Token Repository Service (TRS), which is based on a token repository and a modification of ERS. The TRS stores tokens, which represents the right for a joining node to connect to a certain parent node in the ACK tree. Performance evaluations show that the TRS approach has several advantageous compared to ERS, like improved scalability and independence of the routing protocol.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-10&engl=0}
}
@inproceedings {INPROC-2000-09,
   author = {Christian Maih{\"o}fer},
   title = {{A Bandwidth Analysis of Reliable Multicast Transport Protocols}},
   booktitle = {Proceedings of the 2nd International Workshop on Networked Group Communication (NGC 2000)},
   address = {Palo Alto, USA},
   publisher = {ACM Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {15--26},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2000},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-09/INPROC-2000-09.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2000-09/INPROC-2000-09.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Multicast is an efficient communication technique to save bandwidth for group communication purposes. A number of protocols have been proposed in the past to provide a reliable multicast service. Briefly classified, they can be distinguished into sender-initiated, receiver-initiated and tree-based approaches. In this paper, an analytical bandwidth evaluation of generic reliable multicast protocols is presented. Of particular importance are new classes with aggregated acknowledgments. In contrast to other approaches, these classes provide reliability not only in case of message loss but also in case of node failures. Our analysis is based on a realistic system model, including data packet and control packet loss, asynchronous local clocks and imperfect scope-limited local groups. Our results show that hierarchical approaches are superior. They provide higher throughput as well as lower bandwidth consumption. Relating to protocols with aggregated acknowledgments, the analysis shows only little additional bandwidth overhead and therefore high throughput rates.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-09&engl=0}
}
@inproceedings {INPROC-2000-08,
   author = {J{\"u}rgen Hauser and Kurt Rothermel},
   title = {{Specification and Implementation of an Extensible Multimedia System}},
   booktitle = {Proceedings of the 7th International Workshop on Interactive Distributed Multimedia Systems and Telecommunication Services (IDMS 2000)},
   editor = {Hans Scholten and Marten J. van Sinderen},
   address = {Enschede, Netherlands},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {1905},
   pages = {241--253},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {2000},
   isbn = {3-540-41130-5},
   language = {Englisch},
   cr-category = {H Information Systems},
   contact = {juergen.hauser@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-08&engl=0}
}
@inproceedings {INPROC-2000-07,
   author = {J{\"u}rgen Hauser},
   title = {{Multimedia Authoring with MAVA}},
   booktitle = {Proceedings of the 8th International Conference on Digital Documents and Eletronic Publishing (DDEP'00)},
   address = {Munich, Germany},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2000},
   language = {Englisch},
   cr-category = {H Information Systems},
   contact = {juergen.hauser@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-07&engl=0}
}
@inproceedings {INPROC-2000-06,
   author = {W. Theilmann and K. Rothermel},
   title = {{Dynamic Maps of the Internet}},
   booktitle = {Proceedings of the 19th Annual Joint Conference of the IEEE Computer and Communications Societies (INFOCOM 2000)},
   address = {Tel Aviv, Israel},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2000},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-06&engl=0}
}
@inproceedings {INPROC-2000-04,
   author = {U. Kubach and K. Rothermel},
   title = {{An Adaptive Location-Aware Hoarding Mechanism}},
   booktitle = {Proceedings of the 5th IEEE Symposium on Computers and Communications (ISCC 2000)},
   address = {Antibes, France},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {615--620},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2000},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {When used in an outdoor environment mobile information systems often suffer from the disadvantages of wireless WANs. Hoarding is a method to overcome these disadvantages by transferring information which is probably needed by the user in advance. Existing hoarding mechanisms are either developed for a certain type of application or do not consider the user's location when selecting the information items to hoard. However, exploiting location information can be of great benefit with respect to the achievable hit-ratios. The hoarding mechanism suggested in this paper is both location-aware and universally applicable. Therefore, it can be used as a generic mechanism in a platform which supports different kinds of mobile information systems. In addition, it can be adapted to different degrees of knowledge about the user's movement.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-04&engl=0}
}
@inproceedings {INPROC-2000-03,
   author = {M. Strasser and K. Rothermel},
   title = {{System Mechanisms for Partial Rollback of Mobile Agent Execution}},
   booktitle = {Proceedings of the 20th International Conference on Distributed Computing Systems (ICDCS 2000)},
   address = {Taipei, Taiwan, Republic of China},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {20--28},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2000},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-03&engl=0}
}
@inproceedings {INPROC-2000-02,
   author = {Cora Burger},
   title = {{A Comparison of different platforms for a collaborative distributed document environment}},
   booktitle = {Proceedings of International ICSC Symposium on Multi-Agents and Mobile Agents in Virtual Organizations and E-Commerce (MAMA 2000)},
   editor = {ISA 2000},
   publisher = {ICSC},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {2000},
   keywords = {Joint editing; CORBA; Mobile Agent},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.4.1 Office Automation},
   ee = {http://Festival.informatik.uni-stuttgart.de/,     http://www.icsc-naiso.org/conferences/isa2000/},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In the context of joint working on documents by a team, awareness of each others actions and context as well as consistency of data are crucial aspects. We present two different alternatives to realize a distributed document environment for such purposes. One is based on a CORBA platform, the other one on mobile agents. These approaches are compared according to a number of essential criteria.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2000-02&engl=0}
}
@inproceedings {INPROC-1999-31,
   author = {Steffen Volz and Dieter Fritsch and Darko Klinec and Alexander Leonhardi and Johannes Sch{\"u}tzner},
   title = {{Nexus: Spatial Model Servers for location aware applications on the basis of ArcView}},
   booktitle = {Proceedings of hte 14th ESRI European User Conference},
   address = {M{\"u}nchen},
   publisher = {k.A.},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme;     Universit{\"a}t Stuttgart, Institut f{\"u}r Photogrammetrie (ifp)},
   abstract = {k.A.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-31&engl=0}
}
@inproceedings {INPROC-1999-29,
   author = {Joachim Baumann and Fritz Hohl and Kurt Rothermel and Markus Schwehm and Markus Stra{\ss}er},
   title = {{The Future of Mole}},
   booktitle = {Mobility, Mobile Agents and Process Migration - An Edited Collection},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1999},
   language = {Deutsch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {This short paper describes the future development of the mobile agent system MOLE and applications based on it.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-29&engl=0}
}
@inproceedings {INPROC-1999-23,
   author = {Stefan Wirag},
   title = {{Adaptive Scheduling of Multimedia Documents}},
   booktitle = {Proceedings of the GI/ITG-Fachtagung ``Kommunikation in Verteilten Systemen},
   address = {Darmstadt},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Multimedia documents are of importance in several application areas, such as education, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification resulting in a reduced presentation quality. To cope with those situations, documents can integrate presentation alternatives permitting to adapt the document presentation to different system configurations and load conditions. In this paper, we present an adaptive scheduling algorithm which allows to adapt documents conform to our document model Tiempo in environments with best-effort assignment of resources.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-23&engl=0}
}
@inproceedings {INPROC-1999-21,
   author = {Stefan Wirag},
   title = {{Adaptive Scheduling of Multimedia Documents}},
   booktitle = {Proceedings of the 11. ITG/VDE Fachtagung, Kommunikation in Verteilten Systemen (KiVS '99)},
   address = {Darmstadt},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   contact = {stefan.wirag@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Multimedia documents are of importance in several application areas, such as education, advertising and entertainment. Since multimedia documents may comprise continuous media, such as audio and video, the presentation of those documents may require a significant amount of processing and network resources. The amount of resources available during a presentation depends on the system configuration and the current system load. Hence, it can happen that there are not enough resources to render a multimedia document according to the specification resulting in a reduced presentation quality. To cope with those situations, documents can integrate presentation alternatives permitting to adapt the document presentation to different system configurations and load conditions. In this paper, we present an adaptive scheduling algorithm which allows to adapt documents conform to our document model Tiempo in environments with best-effort assignment of resources.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-21&engl=0}
}
@inproceedings {INPROC-1999-18,
   author = {Wolfgang Theilmann and Kurt Rothermel},
   title = {{Disseminating Mobile Agents for Distributed Information Filtering}},
   booktitle = {Proc. Joint Symposium ASA/MA'99 of 1st Int. Symp. on Agent Systems and Applications (ASA'99) and 3rd Int. Symp. on Mobile Agents (MA'99), Palm Springs (CA), USA, October 3-6, 1999, IEEE Press (to appear)},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {An often claimed benefit of mobile agent technology is the reduction of communication cost. Especially the area of information filtering has been proposed for the application of mobile filter agents. However, an effective coordination of agents, which takes into account the current network conditions, is difficult to achieve. This contribution analyses the situation that data distributed among various remote data servers has to be examined with mobile filter agents. We present an approach for coordinating the agents' employment, which minimizes communication costs. Validation studies on the possible cost savings for various constellations show that savings up to 90\% can be achieved in the face of actual Internet conditions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-18&engl=0}
}
@inproceedings {INPROC-1999-17,
   author = {Uwe Kubach and Kurt Rothermel},
   title = {{A Universal, Location-Aware Hoarding Mechanism}},
   booktitle = {Proceedings of the International Symposium on Handheld and Ubiquitous Computing (HUC '99)},
   address = {Karlsruhe, Germany},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {377--379},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Hoarding is an often used technique to overcome the disadvantages of wireless wide area communication. The basic idea of hoarding is to transfer information to a mobile device before it is actually accessed on the device. The main problem is to decide which information will be needed on the devices. We propose a hoarding mechanism which exploits the fact that the information a user accesses depends on his/her geographic location.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-17&engl=0}
}
@inproceedings {INPROC-1999-16,
   author = {Michael Becht and Thorsten Gurzki and J{\"u}rgen Klarmann and Matthias Muscholl},
   title = {{ROLE: Role Oriented Programming Environment for Multiagent Systems}},
   booktitle = {Proceedings of the Fourth International Conference on Cooperative Information Systems (CoopIS'99)},
   address = {Edinburgh, Scotland},
   publisher = {Los Alamitos, California},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {325--333},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1999},
   isbn = {0-7695-0384-5},
   keywords = {Cooperation Architecture, Multi Agent Framework},
   language = {Englisch},
   cr-category = {F.4 Mathematical Logic and Formal Languages},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {This paper introduces a programming environment and architecture for the development of agent based cooperative applications using a role based approach. We focus on the cooperative aspects by introducing cooperation processes (CP) as a concept of its own. CPs describe all and only the coordination and cooperation parts of an application. The explicit documentation of the coordination and cooperation mechanisms used in a MAS allows their evaluation and reuse. We are able to change existing and introduce new cooperation processes at runtime without modifying the existing agents. We specify the cooperative behaviour of an agent in a separate role description. The interconnection of these roles constitutes the CP. Describing cooperation independent from concrete agents allows to build heterogeneous, federative and transformable MAS. We show how agents decide what roles to accept and how the agent-role interaction works. Finally we present the ROPE framework and runtime environment.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-16&engl=0}
}
@inproceedings {INPROC-1999-15,
   author = {Michael Becht and J{\"u}rgen Klarmann and Ottokar Kulendik and Paul Levi and Matthias Muscholl},
   title = {{A Platform for Supporting Integrated Human and Agent Based Cooperation}},
   booktitle = {Proceedings of the 15th GI/ITG-Fachtagung Architektur von Rechensystemen (ARCS'99)},
   address = {Jena, Germany},
   publisher = {VDE-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {221--224},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1999},
   isbn = {3-8007-2482-0},
   language = {Englisch},
   cr-category = {H.1.0 Information Systems Models and Principles General},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Cooperation between humans is supported by means of workflow management systems and groupware tools, whereas support for agents mainly consists in standardising agent communication languages and developing co-operation protocols. Most of these mechanisms are designed for special situations. Thus, they do not take into account that characteristics of environment, work, persons and agents can change and that relations between dif-ferent cooperations exist. In the following, an innovative cooperation model and platform is introduced. An ex-tended concept of roles and structured communication cares for integration of humans and agents and increases flexibility. Our approach enables to change the organisational structure without the need to restructure the coop-eration protocols and vice versa.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-15&engl=0}
}
@inproceedings {INPROC-1999-14,
   author = {Cora Burger and Oliver Schramm},
   title = {{Co-authoring in dynamic teams with mobile inividuals}},
   booktitle = {Proceedings of the International Symposium on Handheld and Ubiquitous Computing (HUC 99)},
   editor = {Gellersen},
   address = {Karlsruhe, Germany},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {1707},
   pages = {374--376},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1999},
   keywords = {Handheld CSCW; joint editing; CORBA},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.4.1 Office Automation},
   ee = {http://Festival.informatik.uni-stuttgart.de/},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Current solutions to support co-authoring of documents focus on building new systems for participants who are assumed to be connected permanently by a network. We propose an alternate approach, that copes with heterogeneous editing systems and increasing usage of mobile/handheld devices. Each person is allowed to use its favorite editor for isolated as well as for cooperative work. This is achieved by using a global standardized document format and a suited platform. By choosing a wide spread platform, the flexibility to constitute arbitrary teams in spontaneous manner is increased. To treat the mobility problem, participants have representatives in a static part of the network. A prototypical implementation is presented connecting Emacs with LaTex mode to a distributed document environment based on SGML and CORBA.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-14&engl=0}
}
@inproceedings {INPROC-1999-13,
   author = {M. Strasser and J. Baumann and M. Schwehm},
   title = {{An Agent-Based Framework for the Transparent Distribution of Computations}},
   booktitle = {Proceedings of the International Conference on Parallel and Distrbuted Processing Techniques and Applications (PDPTA 1999)},
   address = {Las Vegas, Nevada, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-13&engl=0}
}
@inproceedings {INPROC-1999-12,
   author = {A. Leonhardi and U. Kubach},
   title = {{An Architecture for a Distributed Universal Location Service}},
   booktitle = {Proceedings of the European Wireless '99 Conference},
   address = {Munich, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {351--355},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-12&engl=0}
}
@inproceedings {INPROC-1999-11,
   author = {J{\"u}rgen Hauser},
   title = {{Realization of an Extensible Document Model}},
   booktitle = {Proceedings of the Eurographics Multimedia '99 Workshop},
   address = {Milan, Italy},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Eurographics},
   pages = {113--122},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1999},
   isbn = {3-211-83437-0},
   language = {Englisch},
   cr-category = {H Information Systems},
   contact = {juergen.hauser@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-11&engl=0}
}
@inproceedings {INPROC-1999-10,
   author = {J{\"u}rgen Hauser and Frank Scholze and Uwe Albrecht},
   title = {{MAVA - Entwicklung und Integration eines erweiterbaren multimedialen Dokumentationssystems}},
   booktitle = {Proceedings of the 89th Deutscher Bibliothekartag},
   editor = {Margit R{\"u}tzel-Banz},
   address = {Freiburg, Germany},
   publisher = {Vittorio KLostermann},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {57--69},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {1999},
   isbn = {3-465-02961-5},
   language = {Deutsch},
   cr-category = {H Information Systems},
   contact = {frank.scholze@ub.uni-stuttgart.de juergen.hauser@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-10&engl=0}
}
@inproceedings {INPROC-1999-09,
   author = {A. Leonhardi and U. Kubach and K. Rothermel and A. Fritz},
   title = {{Virtual Information Towers - A Metaphor for Intuitive, Location-Aware Information Access in a Mobile Environment}},
   booktitle = {Proceedings of the Third International Symposium on Wearable Computers (ISCW '99)},
   address = {San Francisco, CA, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {15--20},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-09&engl=0}
}
@inproceedings {INPROC-1999-08,
   author = {Kurt Rothermel and Christian Maih{\"o}fer},
   title = {{A Robust and Efficient Mechanism for Constructing Multicast Acknowledgement Trees}},
   booktitle = {Proceedings of the IEEE Eight International Conference on Computer Communications and Networks (IEEE ICCCN '99)},
   address = {Boston, MA, USA},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {139--147},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1999},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1999-08/INPROC-1999-08.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1999-08/INPROC-1999-08.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {A great variety of todays networked applications require a reliable multicast service. A number of the proposed reliable multicast protocols use a positive acknowledgment scheme, which returns ACKs to the sender to confirm correct delivery. To avoid the well-known implosion problem in the case of large receiver groups, often a tree-based approach is used, i.e., receivers are organized in a tree and ACK messages are passed along the edges of this so-called ACK tree. For building up this tree variations of the Expanding Ring Search (ERS) scheme have been proposed. However, our simulations show that ERS scales poorly. In this paper, we propose an alternative scheme for building up ACK trees. This scheme is based on a so-called token repository service, where a token represents the right to connect to a certain node in the corresponding ACK tree. Nodes that want to join a group just request a token for this group from the (distributed) token repository service. Our simulations show that our scheme causes a much lower message overhead than ERS. Moreover, the quality of the resulting ACK trees in terms of delay and reliability is in many cases higher if generated with our scheme.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-08&engl=0}
}
@inproceedings {INPROC-1999-06,
   author = {L. Feldmann and E. Gilles and A. Reuter and K. Rothermel and V. Sviatniyj and M. Zeitz and G. Hohmann},
   title = {{Frontiers in Simulation}},
   booktitle = {Tagungsband 13, ASIM Symposium Simuolationstechnik},
   address = {Weimar, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-06&engl=0}
}
@inproceedings {INPROC-1999-05,
   author = {F. Hohl and U. Kubach and A. Leonhardi and K. Rothermel and M. Schwehm},
   title = {{Next Century Challenges: Nexus - An Open Global Infrastructure for Spatial-Aware Applications}},
   booktitle = {Proceedings of the Fifth Annual International Conference on Mobile Computing and Networking (MobiCom '99)},
   address = {Seattle, WA, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   pages = {249--255},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Due to the lack of a generic platform for location- and spatial-aware systems, many basic services have to be reimplemented in each application that uses spatial-awareness. A cooperation among different applications is also difficult to achieve without a common platform. In this paper we present a platform that solves these problems. It provides an infrastructure that is based on computer models of regions of the physical world, which are augmented by virtual objects. We show how virtual objects make the integration of existing information systems and services in spatial-aware systems easier. Furthermore, our platform supports interactions between the computer models and the real world and integrates single models in a global ``Augmented World''.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-05&engl=0}
}
@inproceedings {INPROC-1999-04,
   author = {W. Theilmann and K. Rothermel},
   title = {{Maintaining Specialized Search Engines through Mobile Filter Agents}},
   booktitle = {Proceedings of the Third International Workshop on Cooperative Information Agents (CIA'99)},
   address = {Uppsala, Sweden},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Lecture Notes in Artificial Intelligence},
   volume = {1652},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-04&engl=0}
}
@inproceedings {INPROC-1999-03,
   author = {W. Theilmann and K. Rothermel},
   title = {{Efficient Dissemination of Mobile Agents}},
   booktitle = {Proceedings of the Workshop on Electronic Commerce and Web-based Applications at the 19th International Conference on Distributed Computing Systems (ICDCS-99)},
   address = {Austin, Texas, USA},
   publisher = {IEEE Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1999},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-03&engl=0}
}
@inproceedings {INPROC-1999-02,
   author = {Christian Maih{\"o}fer and Kurt Rothermel},
   title = {{Building Multicast Acknowledgement Trees}},
   booktitle = {Proceedings of GI Multicast Workshop},
   address = {Braunschweig, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {129--144},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {1999},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1999-02/INPROC-1999-02.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1999-02/INPROC-1999-02.ps},
   contact = {christian.maihoefer@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {To avoid the well-known implosion problem, the majority of reliable multicast protocols use hierarchical structures to pass acknowledgment messages back to the sender. In most cases, a technique called expanding ring search (ERS) is used to construct the acknowledgment tree. In this paper we analyse ERS by simulation studies. ERS is a simple and fault tolerant approach, but our simulation results show that it has disadvantages like great reliance on the multicast routing protocol and poor scalability. If the background load exceeds a critical level, the message overhead rises exponentially. In this paper, we will present an alternative approach based on a so-called token repository service. The token repository service stores a token for each successor, a node in an ACK tree can accept. To find a node to connect to, the searching node just retrieves a token from the token repository. We describe how such a service can be implemented in a way that it can handle a large number of multicast groups. Our simulation results show that the token repository service is scalable, independent of the multicast routing protocol and builds well-shaped ACK trees, causing message delays that are comparable to ERS or even lower.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1999-02&engl=0}
}
@inproceedings {INPROC-1998-17,
   author = {Joachim Baumann and Fritz Hohl and Kurt Rothermel and Markus Schwehm and Markus Stra{\ss}er},
   title = {{Mole 3.0: A Middleware for Java-Based Mobile Software Agents}},
   booktitle = {Proceedings Middleware'98, Springer Verlag London},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Mole is one of the first Java-based mobile agent systems. It runs on an unmodified Java virtual machine on PCs under Windows 95/NT and on Workstations under several UNIX dialects. Earlier versions of Mole have provided a basic infrastructure for communication and migration of mobile agents. Version of Mole has been strongly revised and several requests and proposals from users of the earlier ver sions of Mole were integrated into the new release. In particular Mole supports communication between agent groups and concept of sessions. The infrastructure of Mole includes a resource manager, a direc tory service and a global naming scheme for agents. In order to support the design of agents, a graphical agent monitor allows to visualize the system behaviour as a whole or of a single agent in particular. Mole further provides a thread management unit to overcome some shortcomings of the Java virtual machine. Mole provides a simple means for installation and configuration of the system. This paper describes the architecture and infrastructure provided by Version 3.0 of Mole.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-17&engl=0}
}
@inproceedings {INPROC-1998-15,
   author = {Cora Burger and Rolf Mecklenburg and Kurt Rothermel},
   title = {{Internetbasiertes Lernen - Interaktive Animation von Kommunikationsprotokollen auf generischem Wege}},
   booktitle = {Proceedings of the GI-Tagung ``Informatik und Ausbildung''},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {176--185},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {1998},
   keywords = {animation; communication protocol},
   language = {Deutsch},
   cr-category = {K.3 Computers and Education,     C.2.2 Network Protocols,     H.5.1 Multimedia Information Systems},
   ee = {http://www.informatik.uni-stuttgart.de/ipvr/vs/projekte/HiSAP/hisap.html},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Im Bereich der Lehre werden traditionell haupts{\"a}chlich Text und Bilder auf Folien oder Dias und im Skript zur Vermittlung von Lehrinhalten eingesetzt. Diese Lehrverfahren sto{\ss}en jedoch an Grenzen, wenn es darum geht, dynamische Prozesse wie z. B. Kommunikationsprotokolle in verteilten Systemen verst{\"a}ndlich zu machen. Da sich Dynamik mit unbewegten Bildern nur eingeschr{\"a}nkt darstellen l{\"a}{\ss}t, gewinnt rechnergest{\"u}tzte Animation in der Lehre an Bedeutung. Au{\ss}erdem sind Lehrvorg{\"a}nge dann am wirkungsvollsten, wenn der Lernende aktiv und gestaltend daran mitwirken kann. Um internetbasiertes und interaktives Erlernen von Protokollen aus dem Bereich der verteilten Systeme auf generischem Wege zu erm{\"o}glichen, und somit eine Verbesserung der Qualit{\"a}t der Lehre auf diesem Sektor zu erreichen, werden im Projekt «ProtoVis« am IPVR der Universit{\"a}t Stuttgart die Programmiersprache Java und das Konstrukt des Java Applets eingesetzt. Diese Applets entstehen durch Konvertierung aus einer formalen Spezifikation des darzustellenden Protokolls in der Beschreibungssprache SDL. Sie stellen die dynamischen Abl{\"a}ufe innerhalb eines Protokolls bildlich und animiert dar und k{\"o}nnen interaktiv gesteuert werden.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-15&engl=0}
}
@inproceedings {INPROC-1998-14,
   author = {Hartmut Benz and Steffen Fischer and Rolf Mecklenburg},
   title = {{A Framework for Integrating Custom Applications into Multimedia Annotations}},
   booktitle = {Proceedings of the European Multimedia, Microprocessor Systems andElectronic Commerce Conference (EMMSEC'98)},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In the ACTS-project DIANE (Design, Implementation and Operation of a Distributed Annotation Environment), a multimedia annotation system has been developed. One of it's greatest benefits over legacy multimedia authoring systems is it's simplicity. It enables users to create multimedia documents instantly without requiring great knowledge of programming languages or other details of the authoring system. Media can be integrated into annotations ranging from standard monomedia objects like audio, images, etc. to recorded application output from legacy applications. The client/server architecture has been implemented in a platform-neutral way using Java and it's extensions (e.g. Java Media Framework) and is running on either Internet/Intranet and broadband network technologies like ATM. This paper will present the architecture and the document model of DIANE with a focus on integrating custom user applications into multimedia annotations. A usage scenario will describe the system in general.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-14&engl=0}
}
@inproceedings {INPROC-1998-13,
   author = {Cora Burger},
   title = {{Fachvortr{\"a}ge {\"U}ber Rechnernetze und Internet}},
   booktitle = {K. Schneider (Hrsg.). Die Informatik AG - Telekooperation. B.G. Teubner Stuttgart, 1998},
   publisher = {Teubner-Stuttgart-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1998},
   language = {Deutsch},
   cr-category = {C Computer Systems Organization},
   ee = {http://medoc.informatik.uni-stuttgart.de/~medoc/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {none},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-13&engl=0}
}
@inproceedings {INPROC-1998-11,
   author = {H. Benz and S. Fischer and R. Mecklenburg},
   title = {{A Framework for Custom Applications into Multimedia Annotations}},
   booktitle = {Proceedings of the European Multimedai, Microprocessor Systems and Electronic Commerce Conference EMMSEC'98},
   address = {Bordeaux, France},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-11&engl=0}
}
@inproceedings {INPROC-1998-10,
   author = {Cora Burger and Kerstin Schneider},
   title = {{Informatik-AG fuer Schuelerinnen - Konzepte und Erfahrungen}},
   booktitle = {Proceedings of GI-Fachtagung ``Informatik und Ausbildung''},
   address = {Stuttgart, Germany},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {133--142},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1998},
   keywords = {Studieninformation; Frauenf{\"o}rderung; gender; computer science},
   language = {Deutsch},
   cr-category = {K.3 Computers and Education},
   ee = {http://www.informatik.uni-stuttgart.de/fakultaet/frauen/frauen.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Anwendersoftware (Prof. Reuter);     Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Einem wachsenden Interesse an weiblichen Absolventen der Informatik von seiten der Industrie steht eine seit einiger Zeit recht niedrige Zahl an Informatikstudentinnen gegen{\"u}ber. Diesem Mi{\ss}verh{\"a}ltnis kann durch vermehrte Information {\"u}ber das Studienfach begegnet werden. Aus diesem Grund wurde im ersten Halbjahr 1997 an der Universit{\"a}t Stuttgart eine Informatik-AG f{\"u}r Sch{\"u}lerinnen durchgef{\"u}hrt. Den Schwerpunkt dieser Veranstaltung bildeten Vortr{\"a}ge durch Mitarbeiterinnen sowie praktische aufgaben an den Rechnern. Im folgenden werden die zugrundeliegenden Konzepte und die unter anderen aus Frageb{\"o}gen gewonnenen Erfahrungen dieses Projektes geschildert.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-10&engl=0}
}
@inproceedings {INPROC-1998-09,
   author = {H. Benz and M.E. Lijding},
   title = {{Asynchronously Replicated Shared Workspaces for a Multi-Media Annotation Service over Internet}},
   booktitle = {Proceedings of the 5th International Workshop on Distributed Multimedia Systems and Telecommunication Services (IDMS 1998)},
   address = {Oslo, Norway},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-09&engl=0}
}
@inproceedings {INPROC-1998-08,
   author = {Cora Burger},
   title = {{Team Awareness with Mobile Agents in Mobile Environments}},
   booktitle = {Proceedings of the 7th International Conference on Computer Communications and Networks (IC3N'98)},
   address = {Lafayette, Louisianna, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {45--49},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1998},
   keywords = {CSCW; team awareness; notification; mobile agents; mobile computing},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.4 Information Storage and Retrieval Systems and Software},
   ee = {http://Festival.informatik.uni-stuttgart.de/},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {There are several aspects involved in supporting human cooperative work by computers. One of them concerns team awareness to avoid unnecessary effort or even chaos. Notification services provide suited information about other team members and team relevant events. Traditionally, such services are realized by a central or distributed approach but exhibit shortcomings with respect to filtering policies and mobility of notified participants. A third alternative consists in applying mobile software agents. In this case, each participant is represented by one immobile and a number of mobile agents. The immobile agent manages all events that are caused by its user. Mobile agents are responsible to observe events being caused by other team members. They communicate either remotely or locally with managers of their partners. Advantages and disadvantages of all possible mechanisms are discussed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-08&engl=0}
}
@inproceedings {INPROC-1998-07,
   author = {J{\"u}rgen Klarmann and Michael Becht and Matthias Muscholl},
   title = {{Modellierung flexibler Workflows mit teilausf{\"u}hrbaren Aktivit{\"a}ten}},
   booktitle = {Proceedings of the Workshop at the German Computer-Supported Cooperative Work Conference (D-CSCW'98)},
   address = {Dortmund, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {44--55},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   keywords = {Workflow Management, Process Modeling, Flexibility},
   language = {Deutsch},
   cr-category = {H.4.1 Office Automation},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Obwohl es allgemein anerkannt ist, da{\ss} Workflow-Management-Systeme flexibel sein m{\"u}ssen, gen{\"u}gen bestehende Mechanismen zur Flexibilisierung von Workflow-Management-Systemen nur in eingeschr{\"a}nkter Weise den Anforderungen des Anwendungsfeldes. Wir f{\"u}hren Modellierungskonzepte ein, mit denen zus{\"a}tzliche Flexibilit{\"a}t modellierbar ist. Wir pr{\"a}sentieren einen Ansatz, der insbesondere das Vor-, Nacharbeiten und {\"U}berspringen und damit das nebenl{\"a}ufige Ausf{\"u}hren von Teilen von Aktivit{\"a}ten sowie einen erweiterten Akteurswechsel unterst{\"u}tzt. Im Gegensatz zu der Methode des Vorformulierens mehrerer Alternativen, bei der die gewonnene Flexibilit{\"a}t durch einen wesentlich h{\"o}heren Modellierungsaufwand bezahlt wird, bleibt bei unserem Ansatz der Modellierungsaufwand ann{\"a}hernd gleich. Dies erfordert eine feingranulare Modellierung der Aktivit{\"a}ten sowie ein feingranulares Modell der Workflow-relevanten Dokumente.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-07&engl=0}
}
@inproceedings {INPROC-1998-06,
   author = {J. Baumann and K. Rothermel},
   title = {{The Shadow Approach: An Orphan Detection Protocol for Mobile Agents}},
   booktitle = {Proceedings of the 2nd International Workshop on Mobile Agents (MA'98)},
   address = {Stuttgart, Germany},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-06&engl=0}
}
@inproceedings {INPROC-1998-05,
   author = {J. Baumann and F. Hohl and K. Rothermel and M. Schwehm and M. Strasser},
   title = {{Mole 3.0: A Middleware for Java-Based Mobile Software Agents}},
   booktitle = {Proceedings of the IFIP International Conference on Distributed Systems, Platforms and Open Distributed Processing (Middleware'98)},
   address = {Lake District, United Kingdom},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-05&engl=0}
}
@inproceedings {INPROC-1998-04,
   author = {K. Rothermel and M. Strasser},
   title = {{A Fault-Tolerant Protocol for Providing the Exaclty-Once Property of Mobile Agents}},
   booktitle = {Proceedings of the 17th IEEE Symposium on Reliable Distributed Systems (SRDS'98)},
   address = {West Lafayette, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-04&engl=0}
}
@inproceedings {INPROC-1998-03,
   author = {C. Burger and R. Mecklenburg and K. Rothermel},
   title = {{Interactive Protocol Simulation Applets for Distance Education}},
   booktitle = {Proceedings of the 5th International Workshop on Interactive Distruted Multimedia Systems and Telecommunication Services (IDMS'98)},
   address = {Oslo, Norway},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-03&engl=0}
}
@inproceedings {INPROC-1998-02,
   author = {M. Strasser and K. Rothermel and C. Maihoefer},
   title = {{Providing Reliable Agents for Electronic Commerce}},
   booktitle = {Proceedings of Trends in Distrbuted Systems for Eletronic Commerce, International IFIP/GI Working Conference (TREC'98)},
   address = {Hamburg, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {241--253},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-02&engl=0}
}
@inproceedings {INPROC-1998-01,
   author = {Wolfgang Theilmann and Kurt Rothermel},
   title = {{Domain experts for Information Retrieval in the World Wide Web}},
   booktitle = {Proceedings of the 2nd International Workshop on cooperative Information Agents},
   address = {Paris, France},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {1998},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1998-01&engl=0}
}
@inproceedings {INPROC-1997-26,
   author = {Joachim Baumann},
   title = {{Neue Objekttechnologien}},
   booktitle = {Informatik und Lernen in der Informationsgesellschaft},
   editor = {W. Luther H.U. Hoppe},
   address = {Berlin, Heidelberg},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   isbn = {3-540-63432-0},
   language = {Deutsch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Objektorientierung und verteilte Objekttechnologien sind heutzutage in aller Munde. Hierbei findet viel Mystifizierung statt, die das Verst{\"a}ndnis erschwert. In diesem Text werden wir uns mit den Begriffen der Objektorientierung besch{\"a}ftigen, um dann verteilte Objekttechnologien wie Corba, ActiveX, OLE und andere beleuchten zu k{\"o}nnen. Wir werden sehen, inwieweit diese den an Objektorientierung gestellten Anspr{\"u}chen tats{\"a}chlich gerecht werden k{\"o}nnen.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-26&engl=0}
}
@inproceedings {INPROC-1997-25,
   author = {Klaus Villinger and Cora Burger},
   title = {{Generic mobile agents for electronic markets}},
   booktitle = {Proceedings of the 4th Conference of the International Society for Decision Support Systems ISDSS'97},
   editor = {Institut d'informatique et organisation},
   address = {Lausanne},
   publisher = {Ecole des HEC},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {205--218},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1997},
   keywords = {mobile agents; electronic market},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     D.1.m Programming Techniques Miscellaneous,     J.1.7 Marketing},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1997-25/INPROC-1997-25.html,     http://www.informatik.uni-stuttgart.de/ipvr/vs/projekte/Festival/festival.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Electronic markets are one important application of agent technology. A common approach consists in representing buyers and sellers of markets by agents. To cope with the whole spectrum of possible market mechanisms, we identified generic parts of such agents. From this, a general framework for generic buying and selling agents was derived. It allows to integrate arbitrary mechanisms for information filtering, for negotiation between agents and for electronic delivery and payment. Based on measurement, we discuss benefits of realizing electronic markets with agent technology.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-25&engl=0}
}
@inproceedings {INPROC-1997-24,
   author = {Thomas Kindler},
   title = {{Activity based security in intranet and internet workflows}},
   booktitle = {Proceedings of the Seventh Annual Workshop on Information Technologies \& Systems,},
   editor = {Arie Segev and Vijay K. Vaishnavi},
   address = {Atlanta, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1997-24/INPROC-1997-24.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {This paper deals with a model to support security requirements of intra-/ internet based workflows. The model is emerged from deficiencies of today's security models in the context of workflows. The basic idea is the consideration of time that extends subject-object based or role based access control models. Access control should be modeled in the context of workflows and their activities and is leading to activity based access control (ABAC). As a result access control will be defined in conjunction with workflows instead of defining them implicitly in enterprise policies.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-24&engl=0}
}
@inproceedings {INPROC-1997-22,
   author = {Joachim Baumann and Christian Tschudin and Jan Vitek},
   title = {{Mobile Object Systems: Workshop Summary}},
   booktitle = {Proc. 2nd ECOOP Workshop on Mobile Object Systems},
   publisher = {dpunkt-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {This workshop summary introduces the notion of Mobile Object Systems, discusses the essentials, generic architectures, and points out the workshop highlights.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-22&engl=0}
}
@inproceedings {INPROC-1997-21,
   author = {Joachim Baumann},
   title = {{Mobility in the Mobile-Agent-System Mole}},
   booktitle = {Proceeding of the 3rd CaberNet Plenary Workshop},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1997-21/INPROC-1997-21.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Mobile agent systems are the focus of many researchers in the area of distributed systems and operating systems since General Magic released their Telescript system in Mobile agent systems add to the well known distributed operating systems the notion of autonomous mobility of its participants, the agents. We will present our agent model and our agent system Mole, and show how mobility is implemented in it.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-21&engl=0}
}
@inproceedings {INPROC-1997-20,
   author = {Hartmut Benz and Sandford Bessler and Steffen Fischer and Hager Michael and Mecklenburg Rolf},
   title = {{DIANE: A Multimedia Annotation System}},
   booktitle = {Proceedings of the Second European Conference on Multimedia Applications, Services and Techniques},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {183--198},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In this paper we introduce a new application called multimedia annotation, which is currently developed in the EU-funded ACTS project DIANE. Starting from the annotation scenarios, we derive different system requirements, a multimedia document model, quality of service and in particular - synchronisation requirements. Abstractions, such as stream components and clocks are presented. The paper concludes with an annotation example, showing the involvement of previously described system components.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-20&engl=0}
}
@inproceedings {INPROC-1997-19,
   author = {Markus Stra{\ss}er and Markus Schwehm},
   title = {{A Performance Model for Mobile Agent Systems}},
   booktitle = {Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {1132--1140},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1997-19/INPROC-1997-19.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {A performance model for the interaction of agents in mobile agent systems is presented. Two interaction models, namely the remote procedure call and the agent migration are considered. Performance models for a single interaction are introduced, which are then used to derive a performance model for a sequence of interactions. This performance model can be used to evaluate the performance of any possible behaviour of an agent in a given scenario. The application of the performance model for a typical scenario in mobile computing shows that the optimal behaviour of an agent is achieved by a mixed sequence of remote procedure calls and agent migrations. The performance model is validated by measurements of interactions of real agents in the mobile agent system Mole.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-19&engl=0}
}
@inproceedings {INPROC-1997-18,
   author = {Joachim Baumann and Fritz Hohl and Nikolaos Radouniklis and Rothermel Kurt and Stra{\ss}er Markus},
   title = {{Communication Concepts for Mobile Agent Systems}},
   booktitle = {Mobile Agents, First International Workshop},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {123--135},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1997-18/INPROC-1997-18.pdf,     ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1997-18/INPROC-1997-18.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Driven by the question how to identify potential communication partners and the need for well-suited communication schemes in agent-based systems, we discuss two communication concepts: sessions and global event management. Sessions establish either actively or passively a context for inter-agent interactions. Communication partners are addressed by globally unique agent identifiers or via badges. Communication in sessions is based on RPC or message mechanisms. Global event management addresses the need for anonymous communication. Event managers are employed as a synchronization means within agent groups. Based on this approach, we introduce synchronization objects, - active components that offer various synchronization services. The presented model is finally mapped onto OMG event services.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-18&engl=0}
}
@inproceedings {INPROC-1997-16,
   author = {H. Benz and S. Fischer and R. Mecklenburg and A. Wenger},
   title = {{Application Output Recording for the Instant Authoring in a Distributed Multimedia Annotation Environment}},
   booktitle = {Proceedings of the 4th International Workshop on Interactive Distribtued Multimedia Systems and Telecommuncation Services (IDMS'97)},
   address = {Darmstadt, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {220--230},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-16&engl=0}
}
@inproceedings {INPROC-1997-14,
   author = {R. Siebert and T. Kindler and T. Soyez},
   title = {{Integrated Workflow Support for the German Government}},
   booktitle = {Proceedings of the 1997 ACM Symposium on Applied Computing},
   address = {Hyatt St. Claire, San Jose, California, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-14&engl=0}
}
@inproceedings {INPROC-1997-13,
   author = {H. Benz and S. Fischer and R. Mecklenburg and A. Wenger},
   title = {{Instant Authoring with Application Output Recording: Taxonomy and Usage in DIANE}},
   booktitle = {Proceedings of the IEEE Conference on Multimedia Computing and Systems (ICMCS'97)},
   address = {Ottawa, Ontario, Canada},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-13&engl=0}
}
@inproceedings {INPROC-1997-11,
   author = {J. Baumann},
   title = {{Mobile Agents and their Role in Future Distributed Systems}},
   booktitle = {Proceedings of the 4th CaberNet Radicals Workshop},
   address = {Rethinmon, Crete},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-11&engl=0}
}
@inproceedings {INPROC-1997-10,
   author = {T. Kindler},
   title = {{Activity Based Securtiy in Intranet and Internet Workflows}},
   booktitle = {Proceedings of the 7th Annual Workshop on Information Technologies and Systems (WITS'97)},
   address = {Atlanta, Georgia, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Dezember},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-10&engl=0}
}
@inproceedings {INPROC-1997-09,
   author = {H. Benz and S. Fischer and R. Mecklenburg and G. Dermler},
   title = {{DIANE: Hypermedia Documents in a Distributed Annotation Environment}},
   booktitle = {Proceedings of the Conference on Hypertext Information Retrieval Multimedia (HIM'97)},
   address = {Dortmund, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-09&engl=0}
}
@inproceedings {INPROC-1997-07,
   author = {H. Benz and S. Fischer and R. Mecklenburg},
   title = {{Technical Overview of an Annotation Service for Medical Training in a Heterogeneous Healthcare Envirionment}},
   booktitle = {Proceedings of the European Workshop on Multimedia Technology in Medical Traning (MTMT'97)},
   address = {Aachen, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-07&engl=0}
}
@inproceedings {INPROC-1997-06,
   author = {H. Benz and S. Fischer and R. Mecklenburg},
   title = {{Architecture and Implementation of a Distributed Multimedia Annotation Environment: Practical Experiences usingJava}},
   booktitle = {Proceedings of the IFIP WG 6.1 International Working Conference on Distributed Applications and Interoperable Systems (DAIS'97)},
   address = {Cottbus, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-06&engl=0}
}
@inproceedings {INPROC-1997-05,
   author = {J. Baumann and N. Radouniklis},
   title = {{Agent Groups in Mobile-Agent Systems}},
   booktitle = {Proceedings of the IFIP WG 6.1 International Workgin Conference on Distrbuted Applications and Interoperable Systems (DAIS'97)},
   address = {Cottbus, GermanyBau},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-05&engl=0}
}
@inproceedings {INPROC-1997-04,
   author = {K. Rothermel and F. Hohl and N. Radouniklis},
   title = {{Mobile Agent Systems: What is missing?}},
   booktitle = {Invited Paper to the IFIP WG 6.1 International Working Conference on Distributed Applications and Interoperable Systems (DAIS'97)},
   address = {Cottbus, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-04&engl=0}
}
@inproceedings {INPROC-1997-03,
   author = {J. Baumann and F. Hohl and N. Radouniklis and K. Rothermel and M. Strasser},
   title = {{Concepts for Mobile Agent Systems}},
   booktitle = {Proceedings of 1st Workshop on Mobile Agents},
   address = {Berlin},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-03&engl=0}
}
@inproceedings {INPROC-1997-02,
   author = {Stefan Wirag},
   title = {{Modeling of Adaptable Multimedia Documents}},
   booktitle = {Proceedings of the 4th International Workshop on Interactive Distributed Multimedia Systems and Telecommunication Services (IDMS'97)},
   address = {Darmstadt, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {220--230},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1997},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1997-02&engl=0}
}
@inproceedings {INPROC-1996-13,
   author = {J. Baumann and C. Tschudin and J. Vitek},
   title = {{Mobile Object Systems: Workshop Summary}},
   booktitle = {Workshop Proceedings of the 2nd ECOOP Workshop on Mobile Object Systems},
   publisher = {Linz, Austria},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-13&engl=0}
}
@inproceedings {INPROC-1996-12,
   author = {Markus Strasser and Joachim Baumann and Fritz Hohl},
   title = {{Mole - A Java Based Mobile Agent System}},
   booktitle = {Workshop Reader of the 10th European Conference on Object-Oriented Programming (ECOOP96)},
   address = {Linz, Austria},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-12&engl=0}
}
@inproceedings {INPROC-1996-11,
   author = {Arno Puder and Cora Burger},
   title = {{New Concepts for Qualitative Trader Cooperation}},
   booktitle = {Proceedings of the IFIP International Conference on Distributed Platforms (ICDP'96)},
   editor = {Schill},
   address = {Dresden, Germany},
   publisher = {IFIP},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {301--313},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1996},
   keywords = {Trading; cooperation; IDL-based types; AI-based types},
   language = {Englisch},
   cr-category = {H.2.4 Database Management Systems,     F.3.3 Studies of Program Constructs},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Traders serve as mediators between service providers and users. The trader returns to a service requester by delivering a set of suitable providers that satisfy the request. Because of the size and complexity of distributed systems, one trader manages a certain part of the whole set of providers only. To enlarge this restricted set of potential service providers, a lightweight form of cooperation (called interworking) between two or more traders was introduced. Therefore, the main purpose of such cooperations was concerned with quantitative aspects, neglecting the possibilities of more general concepts of cooperation. A need for qualitative trader cooperations arises. Traditional trader approaches focus upon the operational interface of providers as a basis for type descriptions. But in general, application users in an open electronic market require mediation at different levels of abstraction. Suitable traders are specialized in one of these levels. By combining these isolated solutions, a qualitative trader cooperation can be achieved. In the following, we take a closer look at type descriptions at different levels of abstraction. Similarities will be discovered that can be used to derive appropriate mappings. In particular we demonstrate that ODP--types based on an arbitrary interface definition language can be described in terms of conceptual graphs that are used in knowledge--based trading. From this relationship, a general type manager can be derived, coping with both type concepts. As a consequence, the trading of operational interfaces and the trading based on a knowledge representation scheme can be combined. Together they exhibit a more powerful trading service by offering different interfaces to different kinds of users.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-11&engl=0}
}
@inproceedings {INPROC-1996-10,
   author = {Tobias Helbig},
   title = {{Timing Control of Stream Handlers in a Distributed Multi-threaded Environment}},
   booktitle = {Proceedings of the 6th International Workshop on Network and Operation Systems Support for Digital Audio and Video (NOSSDAV'96)},
   address = {Zushi, Japan},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-10&engl=0}
}
@inproceedings {INPROC-1996-09,
   author = {Ingo Barth},
   title = {{Configuring Distributed Multimedia Applications Using CINEMA}},
   booktitle = {Proceedings of the IEEE Workshop on Multimedia Software Development (MMSD'96)},
   address = {Berlin},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-09&engl=0}
}
@inproceedings {INPROC-1996-08,
   author = {T. Kindler and T. Soyez},
   title = {{Modelling Security for Integrated Enterprise Workflow and Telecooperation Systems}},
   booktitle = {Proceedings of the IEEE 5th Workshop on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE'96)},
   address = {Stanford University, California, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-08&engl=0}
}
@inproceedings {INPROC-1996-07,
   author = {E. Kovacs},
   title = {{Advanced Trading Service Through Mobile Agents}},
   booktitle = {Proceedings of Trends in Distributed Systems: CORBA and Beyond, International Workshop (TreDS'96)},
   address = {Aachen, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-07&engl=0}
}
@inproceedings {INPROC-1996-06,
   author = {E. Kovacs},
   title = {{Trader Customization Using Mobile Agents}},
   booktitle = {Proceedings of the Seventh IFIP/IEEE International Workshop on Distributed Systems: Operations and Management (DSOM'96)},
   address = {L'Aquila, Italy},
   publisher = {IEEE},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Oktober},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-06&engl=0}
}
@inproceedings {INPROC-1996-05,
   author = {A. Hagin and K. Rothermel and G. Dermler},
   title = {{Issues of Mapping Distributed Multimedia Applications to Distributed Computersystems}},
   booktitle = {Proceedings of the International Conference on informational Networks and Systems (ICINAS-96)},
   address = {St. Petersburg, Russia},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-05&engl=0}
}
@inproceedings {INPROC-1996-04,
   author = {K. Rothermel and G. Dermler and W. Fiederer},
   title = {{A Communication Infrastructure for Multimedia Applications}},
   booktitle = {Proceedings of the European Conference on Networks Optical Communications (NOC'96)},
   address = {Heidelberg},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-04&engl=0}
}
@inproceedings {INPROC-1996-03,
   author = {G. Dermler and W. Fiederer and I. Barth and K. Rothermel},
   title = {{A Negotiation and Resource Reservation Protocol for Configurable Multimedia Applications}},
   booktitle = {Proceedings of the International Conference on Multimedia Computing and Systems (Multimedia 1996)},
   address = {Hiroshima, Japan},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-03&engl=0}
}
@inproceedings {INPROC-1996-02,
   author = {Tobias Helbig and Kurt Rothermel},
   title = {{An Architecture for a Distributed Stream Synchronization Service}},
   booktitle = {Proceeding s of the European Workshop on Interactive Distributd Multimedia Systems},
   address = {Berlin},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-02&engl=0}
}
@inproceedings {INPROC-1996-01,
   author = {T. Magedanz and K. Rothermel and S. Krause},
   title = {{Intelligent Agents: An Emerging Technology for Next Generation Telecommunications?}},
   booktitle = {Proceedings of the INFOCOM 96},
   address = {San Francisco, CA, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {1996},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1996-01&engl=0}
}
@inproceedings {INPROC-1995-09,
   author = {Joachim Baumann},
   title = {{A Triptychon of Problems}},
   booktitle = {Workshop at ECOOP '95: Objects \& Agents: Love at first sight or shotgun wedding?``},
   publisher = {N.N.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1995-09/INPROC-1995-09.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In this position paper three problems of mobile agent systems are discussed. The first is the conceptual problem of security in agent systems. The second, is the speed of the system, and where it is important. The third, following from it, is an implementation problem: how can the transfer size of agents be minimized?},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-09&engl=0}
}
@inproceedings {INPROC-1995-08,
   author = {Stefan Wirag and Kurt Rothermel and Thomas Wahl},
   title = {{Modelling Interaction with HyTime}},
   booktitle = {Kommunikation in Verteilten Systemen, GI/ITG-Fachtagung},
   editor = {K. Franke and U. H{\"u}bner and W. W. Kalfa},
   address = {Chemnitz, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {188--202},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Interactive multimedia presentations are an essential issue in many advanced multimedia application tools. Before presenting multimedia data, media items, interaction types and synchronization constraints have to be specified in a multimedia document. This paper identifies and classifies the temporal interaction types in multimedia systems, and shows their impact on the specification process and the supporting system. Then, we describe how to specify the interaction types by using the standardized multimedia document language HyTime. The HyTime mechanisms are demonstrated by examples followed by a discussion of the advantages and limits of each technique.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-08&engl=0}
}
@inproceedings {INPROC-1995-07,
   author = {Thomas Wahl and Stefan Wirag and Kurt Rothermel},
   title = {{Temporal Modeling and Authoring of Interactive Multimedia}},
   booktitle = {Proceedings of the 2nd. Intl. Conference on Multimedia Computing and Systems},
   address = {Washington D.C., USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {274--277},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Future multimedia titles will provide many ways to interact with the presented information. When creating an interactive multimedia title, the author has to specify the temporal layout and the interaction elements. However, this part of the authoring process is not trivial as the temporal layout and the interaction forms are not independent because some interaction forms affect the presentation schedule of the title. This paper identifies various temporal interaction forms and their temporal dependencies, an integrated model for time and interaction is proposed, and we show how this model is applied to ease rapid authoring of multimedia titles.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-07&engl=0}
}
@inproceedings {INPROC-1995-06,
   author = {Kurt Rothermel and Tobias Helbig},
   title = {{An Adaptive Stream Synchronization Protocol}},
   booktitle = {Proceedings of the 5th International Workshop on Network and Operating System Support for Digital Audio and Video},
   address = {Durham, New Hampshire, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1995-06/INPROC-1995-06.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Protocols for synchronizing data streams should be highly adaptive with regard to both changing network conditions as well as to individual user needs. The Adaptive Synchronization Protocol we are going to describe in this paper supports any type of distribution of the stream group to be synchronized. It incorporates buffer level control mechanisms allowing an immediate reaction on overflow or underflow situations. Moreover, the proposed mechanism is flexible enough to support a variety of synchronization policies and allows to switch them dynamically during presentation. Since control messages are only exchanged when the network conditions actually change, the message overhead of the protocol is very low.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-06&engl=0}
}
@inproceedings {INPROC-1995-05,
   author = {Tobias Helbig and Soufiane Noureddine and Kurt Rothermel},
   title = {{Activation Set: An abstraction for accessing periodic data streams}},
   booktitle = {IS\&T/SPIE Proceedings Vol.2417, Multimedia Computing and Networking'95},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1995-05/INPROC-1995-05.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In distributed multimedia applications time-dependent data streams are conveyed and processed under real-time conditions. The timely accurate activation of the stream handlers processing the data units of streams requires deriving their scheduling times from the temporal properties of the data streams and the amount of data that is processed in each activation. In this paper, we propose the activation set concept as a data access abstraction to consume sets of data units from a group of time-dependent data streams having synchronization relationships among each other. The concept supports the consumption of multiple periodic data streams of different rates as well as the integration of aperiodic streams. It is shown how scheduling times of activations are derived from the streams' temporal properties and the requested amount of data. When a stream handler is activated, data units of the streams are selected for consumption according to synchronization relationships and tolerated skew bounds. The effects of the approach on delays are discussed in the context of a rate-monotonic scheduling algorithm. The concept provides a configurable interface to groups of time-dependent data streams which, for example, is required when mixing streams. It is widely applicable in multimedia system architectures that allow for configuration of distributed multimedia applications based on interconnected stream handling components.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-05&engl=0}
}
@inproceedings {INPROC-1995-04,
   author = {Cora Burger},
   title = {{Cooperation policies for traders}},
   booktitle = {Proceedings IFIP International Conference on Open Distributed Processing ICODP '95},
   editor = {Kerry Raymond and Liz Armstrong},
   publisher = {Chapman and Hall},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {208--218},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1995},
   keywords = {ODP; trading; cooperation},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   contact = {caburger@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {In ODP a general mechanism has been constructed, how cooperation between trader entities can be performed. But little has been said about when and in which cases such a cooperation should be initiated. Furthermore, the above mentioned cooperation mechanism requires an enormous amount of computer and communication resources, counteracting the profit of cooperation, e.g., by degrading the mean response time of traders. As a consequence, policies are needed to resolve such conflicts. In the following, a general cooperation model is introduced and applied to traders. From this general model cooperation policies for traders are derived. One of these policies can be adapted to optimize the quality of trader service by observing the dynamic behaviour of traders, their clients and servers.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-04&engl=0}
}
@inproceedings {INPROC-1995-03,
   author = {Benz Hartmut},
   title = {{KGB; A Customizable Graph Browser}},
   booktitle = {Graph Drawing: Symposium on Graph Drawing, GD '95 Passau, Germany, September 20-22, 1995 Proceedings},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {20--23},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1995-03/INPROC-1995-03.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {This paper presents the architecture of a generic, customizable graph browser KGB. The KGB has been designed to handle very large and dynamically changing graphs which are frequently used as repository management graphs in large applications. Special emphasis has been put on the flexible presentation of the information encoded in the graph and the reduction of the user's workload when adapting the presentation to his or her special needs. The KGB was built as a debugging and visualization tool for document hierarchies of the CASE tool KOGGE currently under development at the Institute for Softwaretechnik, University of Koblenz.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-03&engl=0}
}
@inproceedings {INPROC-1995-02,
   author = {Ingo Barth and Gabriel Dermler and Walter Fiederer},
   title = {{Levels of Quality of Service in CINEMA}},
   booktitle = {GI-SI Jahrestagung, September 18-20, 1995, Z{\"u}rich, Switzerland.},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1995-02/INPROC-1995-02.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Distributed multimedia systems require quality of service at various abstraction levels. At the application level, QoS describes communication in terms of application specific processing units, e.g. frames. At the transport level QoS is used to describe the communication load for the transport system. An architecture integrating the various levels is presented. The architecture provides the framework for performing negotiation of QoS and resource reservation. It includes the specification of a programmer interface and a flowspec carrying QoS information between communication nodes.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-02&engl=0}
}
@inproceedings {INPROC-1995-01,
   author = {Ingo Barth and Tobias Helbig and Kurt Rothermel},
   title = {{Implementierung multimedialer Systemdienste in CINEMA}},
   booktitle = {GI/ITG-Fachtagung ``Kommunikation in Verteilten Systemen''},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1995},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1995-01/INPROC-1995-01.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Die Erstellung verteilter Multimedia-Anwendungen setzt leistungsf{\"a}hige Entwicklungsplattformen voraus, innerhalb deren Probleme wie die {\"U}bertragung multimedialer Daten, die Gew{\"a}hrleistung der Dienstg{\"u}te durch Reservierung von Ressourcen und die Synchronisation von Datenstr{\"o}men gel{\"o}st werden. CINEMA (Configurable INtEgrated Multimedia Architecture) bietet als eine solche Entwicklungsplattform Abstraktionen zur Nutzung multimedialer Systemdienste an, womit funktionale Bearbeitungseinheiten erstellt, komplexe Verarbeitungstopologien in verteilten Systemen aufgebaut und unter Einhaltung von Synchronisations- und Dienstg{\"u}te-Spezifikationen gesteuert werden k{\"o}nnen. In diesem Papier werden nach einem kurzen {\"U}berblick {\"u}ber die Abstraktionen der CINEMA-Dienstschnittstelle die internen Strukturen und Abl{\"a}ufe vorgestellt, mit denen die Multimedia- Dienste in verteilten Systemen erbracht werden.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1995-01&engl=0}
}
@inproceedings {INPROC-1994-08,
   author = {Ern{\"o} Kovacs},
   title = {{Trading und Management verteilter Anwendungen: zentrale Aufgaben f{\"u}r zuk{\"u}nftige verteilte System}},
   booktitle = {1. Aachener Arbeitstreffen ``Neue Konzepte f{\"u}rur die Offene Verteilte Verarbeitung''},
   publisher = {Verlag der Augustinus Buchhandlung},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   series = {Aachener Beitrt{\"a}ge zur Informatik},
   volume = {7},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1994},
   isbn = {3-86073-143-2},
   language = {Deutsch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1994-08/INPROC-1994-08.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-08&engl=0}
}
@inproceedings {INPROC-1994-06,
   author = {Ern{\"o} Kovacs and Stefan Wirag},
   title = {{Trading and Distributed Application Managment:An Integrated Approach}},
   booktitle = {Proceedings of the Fifth IFIP/IEEE International Workshop on Distributed Systems: Operations \& Management (DSOM'94)},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1994},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Trading and distributed application management are two research areas that are strongly related. Trading is a supporting service for distributed systems that utilizes configuration data and current state information to mediate services. Distributed application management collects this information and controls the operation of the system. An integrated approach has to focus on the collaboration of both sides. This paper explores some of the arising problems. The use of configuration information, the notification of events, and access to dynamic state information requires carefully designed interaction interfaces to minimize the effects of communication and distribution on the mediation process. In the other direction, application management can steer the operation and performance of the distributed system through influencing the trading process. We describe our implementation for both approaches and present some exemplary performance measures.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-06&engl=0}
}
@inproceedings {INPROC-1994-05,
   author = {Tobias Helbig and Kurt Rothermel},
   title = {{Programming Abstractions for Handling Multimedia Data in CINEMA}},
   booktitle = {Proceedings of the 2nd CaberNet Plenary Workshop},
   address = {Dublin, Ireland},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {1994},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1994-05/INPROC-1994-05.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-05&engl=0}
}
@inproceedings {INPROC-1994-04,
   author = {Tobias Helbig},
   title = {{Development and Control of Distributed Multimedia Applications}},
   booktitle = {Proceedings of the 4th Open Workshop on High-Speed Networks},
   editor = {Paul K{\"u}hn},
   address = {Brest, France},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {208--213},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1994},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1994-04/INPROC-1994-04.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Distributed multimedia applications make use of high-speed networks to transmit data units. Processing of multimedia data is done at end-systems. Appropriate support is required to provide for integrated processing and communicating of multimedia data streams and for efficient development of distributed multimedia applications. It is given by a middleware layer which uses services of operating systems and networks and enriches them by protocols and mechanisms to offer multimedia system services including multimedia communication, resource reservation, synchronization and configuration management. By that, the gap between system services of general purpose operating systems and the requirements of developing distributed multimedia applications is closed. The CINEMA (Configurable INtEgrated Multimedia Architecture) system is such a middleware layer which offers abstractions to develop arbitrarily structured multimedia applications and provides protocols and mechanisms to control them. Its multimedia system services are accessible via easy-to-use interfaces.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-04&engl=0}
}
@inproceedings {INPROC-1994-03,
   author = {Gabriel Dermler},
   title = {{Ein Konzept zur Integration von Netzwerk-Filtern in verteilte Multimedi-Systemen}},
   booktitle = {Tagungsband der GI-Fachtagung ``Innovationen bei Rechen- und Kommunikationssystemen},
   address = {Hamburg, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1994},
   language = {Deutsch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1994-03/INPROC-1994-03.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Multicast-Uebertragungen mit heterogenen Empfaengern koennen mit Hilfe von Filtern im Netzwerk optimiert werden. Dieser Artikel beschreibt die Einbettung des Filter-Konzepts in eine Architektur, die die Realisierung verteilter Multimedia-Systeme erlaubt. Die Schichtung der Architektur entspricht einer Trennung in Anwendungs- und Systemsicht. Die Rolle des Systems bei der Konfiguration multimedialer Kommunikation sowie der Reservierung von Ressourcen wird beschrieben im Hinblick Teilstrom- und Filterbildung. Die Verzahnung der Ressourcenreservierung und der Propagierung der Filter durchs Netzwerk wird erlaeutert.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-03&engl=0}
}
@inproceedings {INPROC-1994-02,
   author = {Gabriel Dermler and Thomas Gutekunst and Edgar Ostrowski and Frank Ruge},
   title = {{Sharing Audio/Video Applications among Heterogeneous Platforms}},
   booktitle = {Proceedings of the 5th IEEE COMSOC Workshop Multimedia `94},
   address = {Kyoto, Japan},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Mai},
   year = {1994},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {JVTOS (Joint Viewing and Tele-Operation Service), which is being implemented within CEC/RACE II project CIO (R2060), is a new teleservice for high-speed networks enabling distributed users to work in a collaborative fashion with multimedia. Core functionality of JVTOS is provided by an application sharing service that allows multimedia applications to be displayed and interacted with on multiple users' workstations simultaneously. The focus of this paper is on the audio/video elements of shared applications. We discuss the problems of sharing multimedia applications and describe our conception that supports interoperability between heterogeneous platforms.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-02&engl=0}
}
@inproceedings {INPROC-1994-01,
   author = {Gabriel Dermler and Thomas Gutekunst and Edgar Ostrowski and Nelson Pires and Thomas Schmidt and Michael Weber and Heiner Wolf},
   title = {{JVTOS - Multimedia Telecooperation Interconnecting Heterogeneous Platforms}},
   booktitle = {Proceedings of Broadband Islands '94: Connecting with the End-User.},
   editor = {W. Bauerfeld and O. Spaniol and F. Williams},
   address = {Kyoto, Japan},
   publisher = {Elsevier Science B.V.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {463--478},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1994},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1994-01/INPROC-1994-01.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {JVTOS, the ``Joint Viewing and Tele-Operation Service'', is an advanced teleservice allowing distributed users to work in a collaborative fashion with multimedia. JVTOS offers services for multimedia collaboration across high-speed networks and is primarily aimed at running in heterogeneous workstation environments comprising different hardware platforms and also different operating and window systems. JVTOS comprises facilities for session management, floor control, multimedia application sharing, telepointing, and audio/video communication. This paper describes the desgin and implmentation of JVTOS on different platforms. ~},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1994-01&engl=0}
}
@inproceedings {INPROC-1993-06,
   author = {Gabriel Dermler and Thomas Gutekunst and Bernhard Plattner and Edgar Ostrowski and Frank Ruge and Michael Weber},
   title = {{Constructing a Distributed Multimedia Joint Viewing and Tele-Operation Service for Heterogeneous Workstation Environments}},
   booktitle = {Proceedings of the Fourth Workshop on Future Trends in Distributed Systems},
   address = {Lissabon, Portugal},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {8--15},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {1993},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1993-06/INPROC-1993-06.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {JVTOS (Joint Viewing and Tele-Operation Service) is an advanced teleservice to support cooperative work over distance which allows distributed users to work in a collaborative fashion with multimedia. JVTOS comprises facilities for session management, floor control, multimedia application sharing, telepointing and audio/video communication. JVTOS offers services for multimedia collaboration across high-speed networks and is primarily aimed at running in heterogeneous environments comprising different hardware platforms and also different operating and window systems. This paper describes the design of JVTOS as well as its implemeentation on different platforms which is currently under development.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1993-06&engl=0}
}
@inproceedings {INPROC-1993-05,
   author = {Ern{\"o} Kovacs},
   title = {{The MELODY Management System for Distributed Applications}},
   booktitle = {Proceedings of the GI/ITG Workshop ``Development and Management of Distributed Applications},
   address = {Frankfurt, Germany},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1993},
   language = {Deutsch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1993-05/INPROC-1993-05.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Distributed applications contain an inherent complexity which in praxis become apparent through high costs for installation, maintenance and problem determination. This complexity must be reduced by appropriate management tools. The MELODY management system supports the integration of management functions into distributed applications. It realizes an object oriented information model which is directly integrated into the component of a distributed application. The realized object services hides the necessary communication procedures from the application. The supporting management platform enables a location transparent, efficient access with respect to preset actuality requirements. Management applications are supported through functions to monitor and control the system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1993-05&engl=0}
}
@inproceedings {INPROC-1993-04,
   author = {Ern{\"o} Kovacs},
   title = {{Automatic Selection of an Update Strategy for Management Data}},
   booktitle = {Proceedings of the IEEE First International Workshop on System s Management (IWSM'93)},
   address = {Los Angeles, USA},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1993},
   language = {Englisch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1993-04/INPROC-1993-04.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1993-04&engl=0}
}
@inproceedings {INPROC-1993-03,
   author = {Ingo Barth and Gabriel Dermler and Tobias Helbig and Kurt Rothermel and Frank Sembach and Thomas Wahl},
   title = {{CINEMA: Eine konfigurierbare integrierte Multimedia-Architektur}},
   booktitle = {Verteilte Multimedia Systeme, Tagungsband GI/ITG-Arbeitstreffen},
   editor = {Wolfgang Effelsberg and Kurt Rothermel},
   address = {Stuttgart, Germany},
   publisher = {Saur-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {33--47},
   type = {Konferenz-Beitrag},
   month = {Februar},
   year = {1993},
   language = {Deutsch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1993-03/INPROC-1993-03.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Anwendungen ben{\"o}tigen Unterst{\"u}tzung bei der Manipulation multimedialer Daten, um die besonderen Probleme bez{\"u}glich zeitlicher Anforderungen und Ressourcenverwaltung zu bew{\"a}ltigen. Diese zu erbringen, ist die Zielsetzung des CINEMA-Projekts. Hierbei wird eine Systemplattform entwickelt, durch die die Trennung der Funktionen zur Bearbeitung multimedialer Daten von Problemen der Ressourcenverwaltung, der Transportmechanismenvon Problemen der Ressourcenverwaltung, der Transportmechanismen und von zeitlichen Aspekten erm{\"o}glicht wird. Zus{\"a}tzlich bietet die Architektur Abstraktionen zur Modellierung multimedialer Anwendungen bez{\"u}glich der Funktionalit{\"a}t und der Dienstg{\"u}te.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1993-03&engl=0}
}
@inproceedings {INPROC-1993-02,
   author = {Ern{\"o} Kovacs},
   title = {{Abstractions and Hierarchies in a Distributed Management System}},
   booktitle = {Proceedings of the GI/ITG Workshop ``Development and Management of Distributed Applications},
   address = {Dortmund},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1993},
   language = {Deutsch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {(not available)},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1993-02&engl=0}
}
@inproceedings {INPROC-1993-01,
   author = {Ern{\"o} Kovacs},
   title = {{Abstractions and Hierarchies in a Distributed Management System (in German)}},
   booktitle = {Proceedings of the GI/ITG Workshop ``Development and Management of Distributed Applications''},
   publisher = {(not available)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1993},
   language = {Deutsch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {We present a delay analysis of one sender- and two receiver-initiated classes of reliable multicast protocols. Besides the average delivery delay we consider the delay to reliably deliver all packets and the round trip delay. The former two examines the delay between generation of a packet at the sender and correct reception at a randomly chosen receiver or all receivers, respectively. The latter is the delay between generation of a packet at the sender and reception of all acknowledgment packets at the sender. Our numerical results show that receiver-initiated protocols provide significantly better scalability for large receiver groups and transmission rates compared to the sender-initiated protocol. However, the delay of the sender-initiated protocol within its scalability range is substantially lower compared to the receiver-initiated protocols. To assess the quality of our analytical model we have compared the analytical results with a SRM-like protocol simulation. We show that the analytical and simulation results are strongly correlated, which demonstrates the appropriateness of our analytical model.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1993-01&engl=0}
}
@inproceedings {INPROC-1992-02,
   author = {Gabriel Dermler and Konrad Froitzheim},
   title = {{JVTOS - A Reference Model for a New Multimedia Service}},
   booktitle = {Proceedings of the Fourth IFIP Conf. on High Performance Networking},
   address = {Liege, Belgium},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1992},
   keywords = {Distributed Systems; Communications Managment; Multimedia Systems},
   language = {Englisch},
   cr-category = {H Information Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Multimedia Joint Viewing and Teleoperation is a new service for highspeed networks. It allows physically separated users to work in a collaborative fashion with documents and applications. It is however not a cooperative application but a system level service exporting the functionality of applications to many workstations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1992-02&engl=0}
}
@inproceedings {INPROC-1992-01,
   author = {Kurt Rothermel and Gabriel Dermler},
   title = {{Synchronization in Joint-Viewing Environments}},
   booktitle = {Proceedings of the Third Intl. Workshop on Network and Operating System Support for Digital Audio and Video.},
   publisher = {not available},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Germany},
   pages = {97--109},
   type = {Konferenz-Beitrag},
   month = {Januar},
   year = {1992},
   language = {Deutsch},
   cr-category = {H Information Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1992-01/INPROC-1992-01.ps},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte H{\"o}chstleistungsrechner, Verteilte Systeme},
   abstract = {Recent technology advances have made computer-based multimedia cooperation among distributed users feasible. Joint-Viewing (JV) is one such proposed cooperation concept. Correct interaction in it requires synchronization at various levels. In this paper we focus on synchronization aspects on the data stream level. We present several JV scenarios and state for each of these requirements concerning interstream synchronization. Then we introduce basic abstractions of a synchronisazion scheme which is powerful enough to model a variety of JV configurations with their various synchronization needs. The presented scheme is based on the notion of a referencing system which consists of a set of logical clocks each defining a different time zone in the referencing system. Logical clocks provide timing information for input and output devices which are used to produce and consume data in a synchronized fashion.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1992-01&engl=0}
}
@inproceedings {INPROC-1989-02,
   author = {Kurt Rothermel and C. Mohan},
   title = {{ARIES/NT: a Recovery Method Based on Write-ahead Logging for Nested Transactions}},
   booktitle = {Proceedings of the 15th International Conference on Very Large Data Bases (VLDB'89); Amsterdam, The Netherlands},
   address = {San Francisco, CA, USA},
   publisher = {Morgan Kaufmann Publishers Inc.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {337--346},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {1989},
   isbn = {1-55860-101-5},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.2.4 Database Management Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-1989-02/INPROC-1989-02.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {A simple and efficient recovery method for nested transactions, called ARIES/NT (Algorithm for Recovery and Isolation Exploiting Semantics for Nested Transactions), that uses write-ahead logging and supports semantically-rich modes of locking and operation logging is presented. This method applies to a very general model of nested transactions, which includes parlial rollbacks of subtransactions, upward and downward inheritance of locks, and concurrent execution of ancestor and descendent subtransactions. The adopted system architecture encompasses aspects of distributed data base management also. ARIES/NT is an extension of the ARIES recovery and concurrency control method developed recently for the single-level transaction model by Mohan. et. al. in the IBM Research Report RJ6649.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-1989-02&engl=0}
}
@article {ART-2016-24,
   author = {Sukanya Bhowmik and Muhammad Adnan Tariq and Boris Koldehofe and Frank D{\"u}rr and Thomas Kohler and Kurt Rothermel},
   title = {{High Performance Publish/Subscribe Middleware in Software-Defined Networks}},
   journal = {IEEE/ACM Transactions on Networking},
   publisher = {IEEE},
   volume = {25},
   number = {3},
   pages = {1--16},
   type = {Artikel in Zeitschrift},
   month = {Dezember},
   year = {2016},
   isbn = {10.1109/TNET.2016.2632970},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2016-24/ART-2016-24.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2016-24&engl=0}
}
@article {ART-2016-07,
   author = {Thomas Kohler and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Consistent Network Management for Software-defined Networking based Multicast}},
   journal = {IEEE Transactions on Network and Service Management},
   editor = {Rolf Stadler},
   publisher = {IEEE Communications Society},
   pages = {1--1},
   type = {Artikel in Zeitschrift},
   month = {September},
   year = {2016},
   isbn = {10.1109/TNSM.2016.2585672},
   keywords = {Software-defined networking, configuration management, update consistency, quality-of-service management, multicast communication},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.3 Network Operations,     C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2016-07/ART-2016-07.pdf,     http://dx.doi.org/10.1109/TNSM.2016.2585672},
   contact = {thomas.kohler@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Updating a network is an essential and continual task in the management of today{\^a}€™s softwarized networks. When applying updates on distributed network elements, desired network properties, such as drop- and loop-freeness, might be transiently violated. Although being crucial, update consistency has yet been less considered in network management. In this article, we argue for incorporating the particularities of update consistency into the reconfiguration process of continuous network management. We present a generic management architecture allowing for an appropriate selection of an update mechanism and its parameters based on expected inconsistency effects. We investigate update consistency for the case of multicast routing and show in an extensive analysis why simultaneous drop- and duplicate-freeness is not possible. We present an update procedure for multicast routing updates that identifies critical update steps, which are fed back into the reconfiguration process, along with a lightweight approach that allows for the selection of an update strategy, preventing either drops or duplicates. Furthermore, we present an optimization of an existing powerful, but resource-intensive update approach as well as an approach for in-network filtering of duplicates.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2016-07&engl=0}
}
@article {ART-2015-02,
   author = {Ruben Mayer and Boris Koldehofe and Kurt Rothermel},
   title = {{Predictable Low-Latency Event Detection with Parallel Complex Event Processing}},
   journal = {IEEE Internet of Things Journal},
   publisher = {IEEE},
   pages = {1--13},
   type = {Artikel in Zeitschrift},
   month = {Januar},
   year = {2015},
   keywords = {Complex Event Processing, Stream Processing, Data Parallelization, Self-Adaptation, Quality of Service},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     C.4 Performance of Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2015-02/ART-2015-02.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The tremendous number of sensors and smart objects being deployed in the Internet of Things pose the potential for IT systems to detect and react to live-situations. For using this hidden potential, Complex Event Processing (CEP) systems offer means to efficiently detect event patterns (complex events) in the sensor streams and therefore help in realizing a “distributed intelligence” in the Internet of Things. With the increasing number of data sources and the increasing volume at which data is produced, parallelization of event detection is crucial to limit the time events need to be buffered before they actually can be processed. In this article, we propose a pattern-sensitive partitioning model for data streams that is capable of achieving a high degree of parallelism in detecting event patterns which formerly could only be consistently detected in a sequential manner or at a low parallelization degree. Moreover, we propose methods to dynamically adapt the parallelization degree to limit the buffering imposed on event detection in the presence of dynamic changes to the workload. Extensive evaluations of the system behavior show that the proposed partitioning model allows for a high degree of parallelism and that the proposed adaptation methods are able to meet a buffering limit for event detection under high and dynamic workloads.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2015-02&engl=0}
}
@article {ART-2015-01,
   author = {Pericle Perazzo and Pavel Skvortsov and Gianluca Dini},
   title = {{On Designing Resilient Location-Privacy Obfuscators}},
   journal = {The Computer Journal},
   publisher = {Oxford University Press},
   type = {Artikel in Zeitschrift},
   month = {Februar},
   year = {2015},
   doi = {10.1093/comjnl/bxv009},
   keywords = {location-based service; privacy; obfuscation; sharing},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {http://comjnl.oxfordjournals.org/content/early/2015/02/11/comjnl.bxv009.abstract},
   contact = {Pericle Perazzo pericle.perazzo@iet.unipi.it, Pavel Skvortsov skvortsov@hlrs.de, Gianluca Dini gianluca.dini@iet.unipi.it},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The success of location-based services is growing together with the diffusion of GPS-equipped smart devices. As a consequence, privacy concerns are raising year by year. Location privacy is becoming a major interest in research and industry world, and many solutions have been proposed for it. One of the simplest and most flexible approaches is obfuscation, in which the precision of location data is artificially degraded before disclosing it. In this paper, we present an obfuscation approach capable of dealing with measurement imprecision, multiple levels of privacy, untrusted servers, and adversarial knowledge of the map. We estimate its resistance against statistical-based deobfuscation attacks, and we improve it by means of three techniques, namely extreme vectors, enlarge-and-scale, and hybrid vectors.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2015-01&engl=0}
}
@article {ART-2014-07,
   author = {Beate Ottenw{\"a}lder and Boris Koldehofe and Kurt Rothermel and Kirak Hong and David Lillethun and Umakishore Ramachandran},
   title = {{MCEP: A Mobility-Aware Complex Event Processing System}},
   journal = {ACM Transactions Internet Technology},
   editor = {Munindar P. Singh},
   publisher = {ACM},
   volume = {14},
   number = {1},
   pages = {1--24},
   type = {Artikel in Zeitschrift},
   month = {August},
   year = {2014},
   issn = {1533-5399 EISSN:1557-6051},
   keywords = {Mobility, complex event processing, migration, moving range queries},
   language = {Englisch},
   cr-category = {C.2.1 Network Architecture and Design,     C.2.4 Distributed Systems},
   ee = {http://doi.acm.org/10.1145/2633688},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {With the proliferation of mobile devices and sensors, complex event processing (CEP) is becoming increasingly important to scalably detect situations in real time. Current CEP systems are not capable of dealing efficiently with highly dynamic mobile consumers whose interests change with their location. We introduce the distributed mobile CEP (MCEP) system which automatically adapts the processing of events according to a consumer's location. MCEP significantly reduces latency, network utilization, and processing overhead by providing on-demand and opportunistic adaptation algorithms to dynamically assign event streams and computing resources to operators of the MCEP system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2014-07&engl=0}
}
@article {ART-2014-03,
   author = {Marius Wernke and Pavel Skvortsov and Frank D{\"u}rr and Kurt Rothermel},
   title = {{A Classification of Location Privacy Attacks and Approaches}},
   journal = {Personal and Ubiquitous Computing (Special Issue on Security and Trust in Context-Aware Systems)},
   publisher = {Springer London},
   volume = {18},
   number = {1},
   pages = {163--175},
   type = {Artikel in Zeitschrift},
   month = {Januar},
   year = {2014},
   issn = {1617-4909},
   doi = {10.1007/s00779-012-0633-z},
   keywords = {location-based services; location privacy; adversary; attack; classification; location privacy approaches},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2014-03/ART-2014-03.pdf,     http://link.springer.com/article/10.1007%2Fs00779-012-0633-z,     http://www.priloc.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In recent years, location-based services have become very popular, mainly driven by the availability of modern mobile devices with integrated position sensors. Prominent examples are points of interest finders or geo-social networks like Facebook Places, Qype, Loopt. Because these services access private position information, location privacy concepts become mandatory in order to ensure that users accept these services. Many different concepts and approaches for the protection of location privacy have been described in the literature. These approaches differ with respect to the protected information and their effectiveness against different attacks. The goal of this paper is to assess the applicability and effectiveness of location privacy approaches systematically. We first identify different protection goals, namely, personal information (user identity), spatial information (user position), and temporal information (identity/position + time). Secondly, we give an overview of basic principles and existing approaches to protect these privacy goals. In a third step, we classify possible attacks. Finally, we analyzed existing approaches with respect to their protection goals and their ability to resists the introduced attacks.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2014-03&engl=0}
}
@article {ART-2014-01,
   author = {Muhammad Adnan Tariq and Boris Koldehofe and Kurt Rothermel},
   title = {{Securing Broker-Less Publish/Subscribe Systems using Identity-Based Encryption}},
   journal = {IEEE Transactions on Parallel and Distributed Systems},
   address = {Los Alamitos, CA, USA},
   publisher = {IEEE Computer Society},
   volume = {25},
   number = {2},
   pages = {518--528},
   type = {Artikel in Zeitschrift},
   month = {Februar},
   year = {2014},
   doi = {10.1109/TPDS.2013.256},
   issn = {1045-9219},
   keywords = {Identity-based encryption; Routing; Servers; Subscriptions; Distributed Systems; Security and Privacy Protection},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {http://dx.doi.org/10.1109/TPDS.2013.256,     http://doi.ieeecomputersociety.org/10.1109/TPDS.2013.256,     http://www.computer.org/cms/Computer.org/dl/trans/td/2014/02/extras/ttd2014020518s.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The provisioning of basic security mechanisms such as authentication and confidentiality is highly challenging in a content-based publish/subscribe system. Authentication of publishers and subscribers is difficult to achieve due to the loose coupling of publishers and subscribers. Likewise, confidentiality of events and subscriptions conflicts with content-based routing. This article presents a novel approach to provide confidentiality and authentication in a broker-less content-based publish-subscribe system. The authentication of publishers and subscribers as well as confidentiality of events is ensured, by adapting the pairing-based cryptography mechanisms, to the needs of a publish/subscribe system. Furthermore, an algorithm to cluster subscribers according to their subscriptions preserves a weak notion of subscription confidentiality. In addition to our previous work, this article contributes i) use of searchable encryption to enable efficient routing of encrypted events, ii) Multi-credential routing a new event dissemination strategy to strengthen the weak subscription confidentiality, and iii) thorough analysis of different attacks on subscription confidentiality. The overall approach provides fine grained key management and the cost for encryption, decryption and routing is in the order of subscribed attributes. Moreover, the evaluations show that providing security is affordable w.r.t. i) throughput of the proposed cryptographic primitives, and ii) delays incurred during the construction of the publish/subscribe overlay and the event dissemination.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2014-01&engl=0}
}
@article {ART-2013-13,
   author = {Hannes Wolf and Klaus Herrmann and Kurt Rothermel},
   title = {{Dealing with uncertainty: Robust workflow navigation in the healthcare domain}},
   journal = {ACM Transactions on Intelligent Systems and Technology (TIST)},
   address = {New York, NY, USA},
   publisher = {ACM},
   volume = {4},
   number = {4},
   type = {Artikel in Zeitschrift},
   month = {September},
   year = {2013},
   doi = {10.1145/2508037.2508046},
   issn = {2157-6904},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.4.1 Office Automation},
   ee = {http://doi.acm.org/10.1145/2508037.2508046},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Processes in the healthcare domain are characterized by coarsely predefined recurring procedures that are flexibly adapted by the personnel to suite-specific situations. In this setting, a workflow management system that gives guidance and documents the personnel's actions can lead to a higher quality of care, fewer mistakes, and higher efficiency. However, most existing workflow management systems enforce rigid inflexible workflows and rely on direct manual input. Both are inadequate for healthcare processes. In particular, direct manual input is not possible in most cases since (1) it would distract the personnel even in critical situations and (2) it would violate fundamental hygiene principles by requiring disinfected doctors and nurses to touch input devices. The solution could be activity recognition systems that use sensor data (e.g., audio and acceleration data) to infer the current activities by the personnel and provide input to a workflow (e.g., informing it that a certain activity is finished now). However, state-of-the-art activity recognition technologies have difficulties in providing reliable information. We describe a comprehensive framework tailored for flexible human-centric healthcare processes that improves the reliability of activity recognition data. We present a set of mechanisms that exploit the application knowledge encoded in workflows in order to reduce the uncertainty of this data, thus enabling unobtrusive robust healthcare workflows. We evaluate our work based on a real-world case study and show that the robustness of unobtrusive healthcare workflows can be increased to an absolute value of up to 91\% (compared to only 12\% with a classical workflow system). This is a major breakthrough that paves the way towards future IT-enabled healthcare systems.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2013-13&engl=0}
}
@article {ART-2013-04,
   author = {Anders Gidenstam and Boris Koldehofe and Marina Papatriantafilou and Philippas Tsigas},
   title = {{Scalable group communication supporting configurable levels of consistency}},
   journal = {Concurrency and Computation: Practice and Experience},
   publisher = {John Wiley \& Sons, Ltd.},
   volume = {25},
   number = {5},
   pages = {649--671},
   type = {Artikel in Zeitschrift},
   month = {Januar},
   year = {2013},
   doi = {10.1002/cpe.1801},
   keywords = {Distributed Systems, Group Communication, Consistency},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Group communication is deployed in many evolving Internet-scale cooperative applications such as multiplayer online games and virtual worlds to efficiently support interaction on information relevant to a potentially very large number of users or objects. Especially peer-to-peer based group communication protocols have evolved as a promising approach to allow intercommunication between many distributed peers. Yet, the delivery semantics of robust and scalable protocols such as gossiping is not sufficient to support consistency semantics beyond eventual consistency because no relationship on the order of events is enforced. On the other hand, traditional consistency models provided by reliable group communication providing causal or even total order are restricted to support only small groups. This article proposes the cluster consistency model which bridges the gap between traditional and current approaches in supporting both scalability and ordered event delivery. We introduce a dynamic and fault tolerant cluster management method that can coordinate concurrent access to resources in a peer-to-peer system and can be used to establish fault-tolerant configurable cluster consistency with predictable reliability, running on top of decentralised probabilistic protocols supporting scalable group communication. This is achieved by a general two-layered architecture that can be applied on top of the standard Internet communication layers and offers a modular, layered set of services to the applications that need them. Further, we present a fault-tolerant method implementing causal cluster consistency with predictable reliability, running on top of decentralised probabilistic protocols supporting group communication. This paper provides analytical and experimental evaluation of the properties regarding the fault tolerance of the approach. Furthermore, our experimental study, conducted by implementing and evaluating the two-layered architecture on top of standard Internet transport services, shows that the approach scales well, imposes an even load on the system, and provides high-probability reliability guarantees.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2013-04&engl=0}
}
@article {ART-2013-02,
   author = {Marius Wernke and Frank D{\"u}rr and Kurt Rothermel},
   title = {{PShare: Ensuring location privacy in non-trusted systems through multi-secret sharing}},
   journal = {Pervasive and Mobile Computing},
   publisher = {Elsevier},
   pages = {1--17},
   type = {Artikel in Zeitschrift},
   month = {Februar},
   year = {2013},
   doi = {10.1016/j.pmcj.2013.01.001},
   keywords = {Location-based applications; Privacy; Position sharing; Location management},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2013-02/ART-2013-02.pdf,     http://www.priloc.de,     http://dx.doi.org/10.1016/j.pmcj.2013.01.001},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Location-based applications such as Facebook Places, Foursquare, or Loopt typically use location services to manage mobile object positions. However, exposing precise user positions raises user privacy concerns, especially if location service providers are not fully trusted. To enable the secure management of private user positions in non-trusted systems, we present two novel position sharing approaches based on the concept of multi-secret sharing. We improve existing geometric position sharing approaches [1, 2] by considering continuous position updates and by increasing the robustness against various attacks. Furthermore, we present the first position sharing approach for symbolic location models.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2013-02&engl=0}
}
@article {ART-2013-01,
   author = {Stephan Schuhmann and Klaus Herrmann and Kurt Rothermel and Yazan Boshmaf},
   title = {{Adaptive Composition of Distributed Pervasive Applications in Heterogeneous Environments}},
   journal = {ACM Transactions on Autonomous and Adaptive Systems},
   publisher = {ACM},
   volume = {8},
   number = {2},
   pages = {1--21},
   type = {Artikel in Zeitschrift},
   month = {Juli},
   year = {2013},
   doi = {10.1145/2491465.2491469},
   issn = {1556-4665},
   keywords = {Adaptivity; Algorithms; Automation; Components; Design; Heterogeneity; Hybrid Configuration; Management; Measurement; Middleware; Partial Configurations; Pervasive Applications; Service Composition},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     D.2.11 Software Engineering Software Architectures},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2013-01/ART-2013-01.pdf,     http://doi.acm.org/10.1145/2491465.2491469},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Complex pervasive applications need to be distributed for two main reasons: due to the typical resource restrictions of mobile devices, and to use local services to interact with the immediate environment. To set up such an application, the distributed components require spontaneous composition. Since dynamics in the environment and device failures may imply the unavailability of components and devices at any time, finding, maintaining, and adapting such a composition is a nontrivial task. Moreover, the speed of such a configuration process directly influences the user since in the event of a configuration, the user has to wait. In this article, we introduce configuration algorithms for homogeneous and heterogeneous environments. We discuss a comprehensive approach to pervasive application configuration that adapts to the characteristics of the environment: It chooses the most efficient configuration method for the given environment to minimize the configuration latency. Moreover, we propose a new scheme for caching and reusing partial application configurations. This scheme reduces the configuration latency even further such that a configuration can be executed without noticeable disturbance of the user.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2013-01&engl=0}
}
@article {ART-2012-21,
   author = {Ralph Lange},
   title = {{Scalable Management of Trajectories and Context Model Descriptions}},
   journal = {PIK -- Praxis der Informationsverarbeitung und Kommunikation},
   publisher = {De Gruyter},
   volume = {35},
   number = {4},
   pages = {281--287},
   type = {Artikel in Zeitschrift},
   month = {November},
   year = {2012},
   doi = {10.1515/pik-2012-0041},
   isbn = {ISSN 1865-8342},
   keywords = {moving objects database; trajectory tracking; spatio-temporal indexing; heterogeneous information systems; defined classes},
   language = {Englisch},
   cr-category = {H.2.5 Heterogeneous Databases,     H.2.8 Database Applications,     H.3.3 Information Search and Retrieval},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2012-21/ART-2012-21.pdf},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The ongoing proliferation of sensing technologies constitutes a huge potential for context-aware computing. It allows selecting relevant information about our physical environment from different sources and providers all over the globe. A fundamental challenge is how to provide efficient access to these immense amounts of distributed dynamic context information - particularly due to the mobility of devices and other entities. To enable such access to current and past position information about moving objects, we propose a family of protocols (CDR, GRTS) for efficiently tracking a moving object's trajectory at some remote database in real-time as well as a distributed indexing scheme (DTI) for optimized access to trajectory data that is partitioned in space to multiple database servers. For discovering context information that is relevant for the situation of an application, we propose a powerful formalism for describing context models in a concise manner and a tailored multidimensional data structure (SDC-Tree) for retrieving relevant context models out of potentially millions of descriptions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2012-21&engl=0}
}
@article {ART-2012-18,
   author = {Kurt Rothermel and Stephan Schnitzer and Ralph Lange and Frank D{\"u}rr and Tobias Farrell},
   title = {{Context-aware and quality-aware algorithms for efficient mobile object management}},
   journal = {Pervasive and Mobile Computing},
   publisher = {Elsevier},
   volume = {8},
   number = {1},
   pages = {131--146},
   type = {Artikel in Zeitschrift},
   month = {Februar},
   year = {2012},
   doi = {10.1016/j.pmcj.2011.04.009},
   issn = {1574-1192},
   keywords = {context-awareness; location management; mobile object tracking; range queries; efficiency},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks,     H.2.8 Database Applications},
   ee = {http://dx.doi.org/10.1016/j.pmcj.2011.04.009},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {The management of positions of mobile objects is an essential prerequisite for many context-aware systems such as advanced traffic management systems or personal assistance systems. In this paper, we present two approaches for the scalable tracking of mobile object trajectories and the efficient processing of continuous spatial range queries, respectively. We show in detail how both approaches utilize the basic concepts of accuracy relaxation and utilization of context information, such as movement predictions, to minimize the number of position updates, the size of trajectory data, and the number of energy-consuming position sensing operations.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2012-18&engl=0}
}
@article {ART-2012-17,
   author = {Umakishore Ramachandran and Kirak Hong and Liviu Iftode and Ramesh Jain and Rajnish Kumar and Kurt Rothermel and Junsuk Shin and Raghupathy Sivakumar},
   title = {{Large-Scale Situation Awareness With Camera Networks and Multimodal Sensing}},
   journal = {Proceedings of the IEEE},
   publisher = {IEEE},
   volume = {100},
   number = {4},
   pages = {878--892},
   type = {Artikel in Zeitschrift},
   month = {April},
   year = {2012},
   issn = {0018-9219},
   doi = {10.1109/JPROC.2011.2182093},
   keywords = {Cameras; Computer vision; Intelligent sensors; Large-scale systems; Real time systems; Resource management; Surveillance; Target tracking; Video recording; cameras; image sensors; multimedia communication; ubiquitous computing; video surveillance; Moore law; data-intensive nature; disaster recovery; emergency response; functional situation awareness system; health care; ill-defined research area; large-scale camera network deployment; large-scale reliable system; large-scale situation awareness; media-rich sensor-based application; multimedia algorithm; multimodal sensing; real-time analysis; resource requirement; sensing data; Large-scale distributed systems; programing model; resource management; scalability; situation awareness; video-based surveillance},
   language = {Deutsch},
   cr-category = {C.2 Computer-Communication Networks,     I.4 Image Processing and Computer Vision,     D.1 Programming Techniques},
   ee = {http://dx.doi.org/10.1109/JPROC.2011.2182093},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Sensors of various modalities and capabilities, especially cameras, have become ubiquitous in our environment. Their intended use is wide ranging and encompasses surveillance, transportation, entertainment, education, healthcare, emergency response, disaster recovery, and the like. Technological advances and the low cost of such sensors enable deployment of large-scale camera networks in large metropolises such as London and New York. Multimedia algorithms for analyzing and drawing inferences from video and audio have also matured tremendously in recent times. Despite all these advances, large-scale reliable systems for media-rich sensor-based applications, often classified as situation-awareness applications, are yet to become commonplace. Why is that? There are several forces at work here. First, the system abstractions are just not at the right level for quickly prototyping such applications on a large scale. Second, while Moore's law has held true for predicting the growth of processing power, the volume of data that applications are called upon to handle is growing similarly, if not faster. Enormous amount of sensing data is continually generated for real-time analysis in such applications. Further, due to the very nature of the application domain, there are dynamic and demanding resource requirements for such analyses. The lack of right set of abstractions for programing such applications coupled with their data-intensive nature have hitherto made realizing reliable large-scale situation-awareness applications difficult. Incidentally, situation awareness is a very popular but ill-defined research area that has attracted researchers from many different fields. In this paper, we adopt a strong systems perspective and consider the components that are essential in realizing a fully functional situation-awareness system.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2012-17&engl=0}
}
@article {ART-2012-04,
   author = {Andreas Grau and Klaus Herrmann and Kurt Rothermel},
   title = {{Scalable Network Emulation - The NET Approach}},
   journal = {Journal of Communications - Special Issue: Advances in Communications and Networking - II},
   publisher = {Academy Publisher},
   volume = {7},
   number = {1},
   pages = {3--16},
   type = {Artikel in Zeitschrift},
   month = {Januar},
   year = {2012},
   issn = {1796-2021},
   doi = {10.4304/jcm.7.1.3-16},
   keywords = {Scalable Network Emulation; Placement; Migration; Node Virtualization; Virtual Time},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Network emulation is an efficient method for evaluating distributed applications and communication protocols bycombining the benefits of real world experiments and networksimulation. The process of network emulation involves the executionof connected virtual nodes running the software under test ina controlled environment. Our Network Emulation Testbed (NET) achieves high scalability by combining efficient node virtualization and adaptive virtual time. In this paper, we provide an overview of our system. First, we introduce our efficient emulation architecture. Second, we present our approaches (NETplace and NETbalance) to minimize the runtime of the network experiments. The idea of NETplace is to minimize the load of the testbed by calculating an initial placement of virtual nodes onto the testbed nodes. During the runtime of the experiment NETbalance adapts this placement to changed resource requirements of the software under test. Finally, we introduce NETcaptain, a graphical user interface to setup, control and visualize network experiments.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2012-04&engl=0}
}
@article {ART-2011-21,
   author = {Tobias Farrell and Kurt Rothermel and Reynold Cheng},
   title = {{Processing Continuous Range Queries with Spatiotemporal Tolerance}},
   journal = {IEEE Journal Transactions on Mobile Computing (TCM)},
   publisher = {IEEE Computer Society},
   volume = {10},
   number = {3},
   pages = {320--334},
   type = {Artikel in Zeitschrift},
   month = {M{\"a}rz},
   year = {2011},
   doi = {10.1109/TMC.2010.159},
   issn = {1536-1233},
   keywords = {accuracy; delay; energy consumption; sensors; uncertainty; query; spatial; temporal; spatiotemporal},
   language = {Englisch},
   cr-category = {C.2 Computer-Communication Networks},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Continuous queries are often employed to monitor the locations of mobile objects (MOs), which are determined by sensing devices like GPS receivers. In this paper, we tackle two challenges in processing continuous range queries (CRQs): coping with data uncertainty inherently associated with location data, and reducing the energy consumption of battery-powered MOs. We propose the concept of spatiotemporal tolerance for CRQ to relax a query's accuracy requirements in terms of a maximal acceptable error. Unlike previous works, our definition considers tolerance in both the spatial and temporal dimensions, which offers applications more flexibility in specifying their individual accuracy requirements. As we will show, these tolerance bounds can provide well-defined query semantics in spite of different sources of data uncertainty. In addition, we present efficient algorithms that carefully control when an MO should sense or report a location, while satisfying these tolerances. Thereby, we particularly reduce the number of position sensing operations substantially, which constitute a considerable source of energy consumption. Extensive simulations confirm that the proposed algorithms result in large energy savings compared to nontolerant query processing.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2011-21&engl=0}
}
@article {ART-2011-11,
   author = {Ralph Lange and Frank D{\"u}rr and Kurt Rothermel},
   title = {{Efficient real-time trajectory tracking}},
   journal = {The VLDB Journal},
   publisher = {Springer Berlin Heidelberg},
   volume = {20},
   number = {5},
   pages = {671--694},
   type = {Artikel in Zeitschrift},
   month = {Oktober},
   year = {2011},
   doi = {10.1007/s00778-011-0237-7},
   issn = {1066-8888},
   keywords = {moving objects database; MOD; trajectory tracking; dead reckoning; line simplification},
   language = {Englisch},
   cr-category = {H.2.8 Database Applications},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2011-11/ART-2011-11.pdf,     http://dx.doi.org/10.1007/s00778-011-0237-7},
   contact = {ralph.lange@ipvs.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Moving objects databases (MOD) manage trajectory information of vehicles, animals, and other mobile objects. A crucial problem is how to efficiently track an object's trajectory in real-time, in particular if the trajectory data is sensed at the mobile object and thus has to be communicated over a wireless network. We propose a family of tracking protocols that allow trading the communication cost and the amount of trajectory data stored at a MOD off against the spatial accuracy. With each of these protocols, the MOD manages a simplified trajectory that does not deviate by more than a certain accuracy bound from the actual movement. Moreover, the different protocols enable several trade-offs between computational costs, communication cost, and the reduction in the trajectory data: Connection-Preserving Dead Reckoning minimizes the communication cost using dead reckoning, a technique originally designed for tracking an object's current position. Generic Remote Trajectory Simplification (GRTS) further separates between tracking of the current position and simplification of the past trajectory and can be realized with different line simplification algorithms. For both protocols, we discuss how to bound the space consumption and computing time at the moving object and thereby present an effective compression technique to optimize the reduction performance of real-time line simplification in general. Our evaluations with hundreds of real GPS traces show that a realization of GRTS with a simple simplification heuristic reaches 85-90\% of the best possible reduction rate, given by retrospective offline simplification. A realization with the optimal line simplification algorithm by Imai and Iri even reaches more than 97\% of the best possible reduction rate.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2011-11&engl=0}
}
@article {ART-2011-01,
   author = {Muhammad Adnan Tariq and Boris Koldehofe and Gerald G. Koch and Imran Khan and Kurt Rothermel},
   title = {{Meeting subscriber-defined QoS constraints in publish/subscribe systems}},
   journal = {Concurrency and Computation: Practice and Experience},
   publisher = {John Wiley \& Sons, Ltd.},
   volume = {23},
   number = {17},
   pages = {2140--2153},
   type = {Artikel in Zeitschrift},
   month = {Mai},
   year = {2011},
   doi = {10.1002/cpe.1751},
   keywords = {Content-based; P2P; Event-based; Bandwidth; End-to-end Delay; Spatial indexing; QoS},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2011-01/ART-2011-01.pdf,     http://dx.doi.org/10.1002/cpe.1751},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Current distributed publish/subscribe systems assume that all participants have similar QoS requirements and equally contribute to the system's resources. However, in many real-world applications, the message delay tolerance of individual peers may differ widely. Disseminating messages according to individual delay requirements not only allows for the satisfaction of user-specific needs but als