Institut für Parallele und Verteilte Systeme (IPVS)

Publikationen

Eine Übersicht der Publikationen des Instituts für Parallele und Verteilte Systeme

Publikationen VS: Bibliographie 2005 BibTeX

 
@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}
}
@article {ART-2005-19,
   author = {Christian Becker and Frank D{\"u}rr},
   title = {{On Location Models for Ubiquitous Computing}},
   journal = {Personal and Ubiquitous Computing},
   publisher = {Springer-Verlag},
   volume = {9},
   number = {1},
   pages = {20--31},
   type = {Artikel in Zeitschrift},
   month = {Januar},
   year = {2005},
   keywords = {Location Model; Umgebungsmodell, Ubiquitous Computing; Context-aware Computing; Location-based Services},
   language = {Englisch},
   cr-category = {H.0 Information Systems General},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2005-19/ART-2005-19.pdf,     http://www.springerlink.com/content/7qjyl3g9hly15ky2/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {Common queries regarding information processing in ubiquitous computing are based on the location of physical objects. No matter if the next printer, next restaurant, or friend is searched for, a notion of distances between objects is required. A search for all objects in a certain geographic area requires the possibility to define spatial ranges and spatial inclusion of locations. In this paper we discuss general properties of symbolic and geometric coordinates. Based on that, we present an overview of existing location models allowing for position, range, and nearest neighbor queries. The location models are classified according to their suitability with respect to the query processing and the involved modeling effort along with other requirements. Besides an overview of existing location models and approaches the classification of location models with respect to application requirements can assist developers in their design decisions.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-19&engl=0}
}
@article {ART-2005-08,
   author = {Marcus Handte and Christian Becker and Kurt Rothermel},
   title = {{Peer-based Automatic Configuration of Pervasive Applications}},
   journal = {Journal of Pervasive Computing and Communications},
   publisher = {Troubadour Publishing},
   volume = {1},
   number = {4},
   pages = {251--264},
   type = {Artikel in Zeitschrift},
   month = {Dezember},
   year = {2005},
   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 = {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 their ever-changing execution environments without user intervention. To ease the development of adaptive applications, Becker et al. [3] have proposed the peer-based component system PCOM. This system provides fundamental mechanisms to support the automated composition of applications at runtime. In this article, we discuss the requirements on algorithms that enable automatic configuration of pervasive applications. Furthermore, we show how finding a configuration can be interpreted as Distributed Constraint Satisfaction Problem. Based on this, we present an algorithm that is capable of finding an application configuration in the presence of strictly limited resources. To show the feasibility of this algorithm, we present an evaluation based on simulations and real-world measurements and we compare the results with a simple greedy approximation.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-08&engl=0}
}
@article {ART-2005-06,
   author = {Pedro Jos{\'e} Marr{\'o}n and Andreas Lachenmann and Daniel Minder and Matthias Gauger and Olga Saukh and Kurt Rothermel},
   title = {{Management and configuration issues for sensor networks}},
   journal = {International Journal of Network Management},
   publisher = {John Wiley \& Sons, Inc.},
   volume = {15},
   number = {4},
   pages = {235--253},
   type = {Artikel in Zeitschrift},
   month = {Juli},
   year = {2005},
   isbn = {1099-1190},
   keywords = {wireless sensor network; self-organization; code distribution},
   language = {Englisch},
   cr-category = {C.2.3 Network Operations,     C.2.1 Network Architecture and Design},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2005-06/ART-2005-06.pdf,     http://www.interscience.wiley.com},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we define three of the key issues that need to be solved in order to provide efficient management and configuration of applications and system software in sensor networks: the distribution and management of roles within the network, efficient code distribution algorithms, and efficient on-the-fly code update algorithms for sensor networks. The first issue is motivated by the increasing heterogeneity of sensor network applications and their need for more complex (nonhomogeneous) network topologies and structures. The second one is motivated by the intrinsic energy constraint issues and, in general, the resource limitation of sensor networks. Finally, the third one is needed due to the nature of monitoring applications and optimization needs from applications that should be able to efficiently incorporate code updates so that the network can adapt to its surroundings on the fly. In this paper we present related work and some results for each of these issues as we have dealt with them within the TinyCubus project.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-06&engl=0}
}
@article {ART-2005-05,
   author = {Pedro Jos{\'e} Marr{\'o}n and Daniel Minder and Andreas Lachenmann and Kurt Rothermel},
   title = {{TinyCubus: An Adaptive Cross-Layer Framework for Sensor Networks}},
   journal = {it - Information Technology},
   publisher = {Oldenbourg Verlag},
   volume = {47},
   number = {2},
   pages = {87--97},
   type = {Artikel in Zeitschrift},
   month = {April},
   year = {2005},
   isbn = {1611-2776},
   keywords = {wireless 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/ART-2005-05/ART-2005-05.pdf,     http://www.it-inftech.de},
   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 cross-layer framework that enables optimizations through cross-layer interactions, a configuration engine that distributes components efficiently by considering the roles of the sensor nodes and provides support to install components dynamically, and a data management framework that selects and adapts both system and data management components. Finally, relevant research challenges associated with the development of each framework are identified and discussed in the paper.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-05&engl=0}
}
@article {ART-2005-03,
   author = {Audun J{\o}sang and Elizabeth Gray and Michael Kinateder},
   title = {{Simplification and Analysis of Transitive Trust Networks}},
   journal = {Web Intelligence and Agent Systems: An International Journal},
   address = {Amsterdam, The Netherlands},
   publisher = {IOS Press},
   pages = {1--1},
   type = {Artikel in Zeitschrift},
   month = {September},
   year = {2005},
   issn = {1570-1263},
   keywords = {trust, reputation, transitive, transitivity, trust-graph, trust-chains},
   language = {Englisch},
   cr-category = {J.4 Social and Behavioral Sciences,     C.2.4 Distributed Systems,     H.3.5 Online Information Services},
   ee = {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 = {When transacting and interacting through open computer networks, traditional methods used in the physical world for establishing trust can no longer be used. Creating virtual network substitutes with which people, organisations and software agents can derive trust in other parties requires computerised analysis of the underlying trust networks. This article describes an approach to trust network analysis using subjective logic (TNA-SL), that consists of the three following elements. Firstly it uses a concise notation with which trust transitivity and parallel combination of trust paths can be expressed. Secondly it defnes a method for simplifying complex trust networks so that they can be expressed in this concise form. Finally it allows trust measures to be expressed as beliefs, so that derived trust can be automatically and securely computed with subjective logic. We compare our approach with trust derivation algorithms that are based on normalisation such as PageRank and EigenTrust. We also provide a numerical example to illustrates how TNA-SL can be applied.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-03&engl=0}
}
@article {ART-2005-02,
   author = {Michael Kinateder and Ralf Terdic and Kurt Rothermel},
   title = {{Trusting Pseudonyms – Anonymous Communication in Peer-to-Peer Reputation Systems}},
   journal = {International Journal for Infonomics},
   publisher = {e-Centre for Infonomics},
   pages = {1--1},
   type = {Artikel in Zeitschrift},
   month = {September},
   year = {2005},
   isbn = {ISSN 1742-4720},
   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 = {http://unitec.informatik.uni-stuttgart.de/,     http://www.i-journal.org.uk/Special-issues/Special-Issues.htm},
   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 novel approach to enable untraceable communication between pseudonyms. Our work provides strong sender and recipient anonymity 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). In order to communicate, a sender requests from the DHT the recipient’s routing header, which is 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 suitable for various other application areas as well. We have implemented a prototype of UniTEC and present results from an ongoing evaluation in our network emulation testbed.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2005-02&engl=0}
}
 
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