Institut für Parallele und Verteilte Systeme (IPVS)

Publikationen

Eine Übersicht der Publikationen des Instituts für Parallele und Verteilte Systeme

Publikationen VS: Bibliographie 2010 BibTeX

 
@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}
}
@article {ART-2010-03,
   author = {Sven Schulz and Wolfgang Blochinger and Mathias Poths},
   title = {{Orbweb - A Network Substrate for Peer-to-Peer Grid Computing Platforms based on Open Standards}},
   journal = {Journal of Grid Computing},
   address = {Heidelberg},
   publisher = {Springer-Verlag},
   volume = {8},
   number = {1},
   pages = {77--107},
   type = {Artikel in Zeitschrift},
   month = {Juni},
   year = {2010},
   doi = {10.1007/s10723-009-9121-8},
   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},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Verteilte Systeme},
   abstract = {In this paper, we propose to use the open industrial-strength eXtensible Messaging and Presence Protocol (XMPP) to build a network substrate for Peer-to-Peer Grid computing called Orbweb. We describe how to employ XMPP to tackle domain-specific challenges, including high scalability, support for volatility, NAT/Firewall traversal, and protocol efficiency. Where XMPP fails to meet these requirements, we contribute pertinent extensions. In particular, we boost the scalability of XMPP by taking load of the XMPP servers through dynamically negotiated direct Peer-to-Peer communication channels between XMPP peers. We pave the way for scalable group membership management by substituting the existing XMPP Multi-User Chat protocol for one that does not suffer from limitations imposed by a everyone knows everyone visibility model and allows for selecting a membership model that matches the requirements of a given application. As efficient multicasting is an essential prerequisite for many distributed algorithms and the centralized XMPP multicast is of limited scalability, we adapt the well-known Bimodal Multicast protocol to work in a highly volatile Peer-to-Peer Grid computing environment. Finally, we show how to improve the protocol efficiency of XMPP by leveraging a standardized binary encoding of the XML Information Set for XMPP packet transmission. To substantiate the applicability of our approach and the effectiveness of our extensions, we describe how some important higher-level services used in Peer-to-Peer Grid Computing can be implemented on top of Orbweb and provide a detailed experimental analysis.},
   url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2010-03&engl=0}
}
 
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