@inproceedings {18, title = {Location-Detection Strategies in Pervasive Computing Environments}, booktitle = {Proc. of the IEEE Conference on Pervasive Computing (PERCOM)}, year = {2003}, month = {March}, publisher = {IEEE Press}, organization = {IEEE Press}, address = {Texas, USA}, abstract = {

Pervasive computing environments accommodate interconnected and communicating mobile devices. Mobility is a vital aspect of everyday life and technology must offer support for moving users, objects, and devices. Their growing number has strong implications on the bandwidth of wireless and wired networks. Network bandwidth becomes a scare resource and its efficient use is crucial for the quality of service in pervasive computing. In this article we study process models for detecting location changes of moving objects and their effect on the network bandwidth. We simulate a scenario of pow(10,4) moving objects for a period of pow(10,7) time cycles while monitoring the quality of service with respect to network bandwidth for different location detection strategies. The simulation shows that the class of strategies implementing a synchronous model offers better quality of service than the timed model. We conclude the article with a set of guidelines for the application of the strategies we have investigated.

}, keywords = {location-based systems, mobile shadow}, isbn = {0-7695-1893-1}, doi = {10.1109/PERCOM.2003.1192750}, url = {http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1192750}, author = {Fischmeister, Sebastian and Guido Menkhaus and Alexander Stumpfl} } @mastersthesis {15, title = {Location Context in Mobile and Pervasive Computing Systems: Technologies, Architectures \& Implementation}, year = {2002}, month = {11/2002}, pages = {146}, school = {University of Salzburg}, type = {mastersmastersphd}, address = {Salzburg}, abstract = {

Technological advances allow manufacturing of smaller and more portable, yet increasingly powerful computing devices, which are equipped with wireless communicating capabilities. The integration of information processing into wirelessly interconnected everyday objects is the primary goal of pervasive computing. A pragmatic variant of the pervasive computing paradigm has been described by IBM chairman Lou Gerstner: a billion people interacting with a million e-businesses through a trillion interconnected intelligent devices. Persons move around, and therefore it is important for such a scenario to operate so that e-businesses and the interconnected devices know where they are and what other objects are in their vicinity. Location information seems crucial information for e-businesses and services. The pervasive environment is strongly interconnected, and the participants profit from this fact by detecting their surroundings and offering proactive service to objects in their vicinity. This work examines the location context in mobile and pervasive computing systems. Thereby, it investigates the impact of mobile and pervasive computing on location-based systems, and especially concentrates on proactive services, i.e., services that act on behalf of the user. To begin, the thesis probes standard locating algorithms and determines their applicability for proactive services. Then, it proposes adaptations to these algorithms through a novel mapping between locations and objects (formalizing the difference between locating and location systems). Next, it presents the proof-of-concept implementation (called Mobile Shadow) in detail to support the claims made in the first part. It starts with presenting the computation and data model for Mobile Shadow. Then, it shows by simulation that the model is sound and that the adaptations are valid and improve the overall quality of service. Finally, it presents implementation details such as the location system and how to create a new service. After presenting the proof-of-concept implementation, this thesis evaluates in detail the software architectures of Mobile Shadow and two more architecture prototypes suitable for location-based systems. Based on this evaluation and the discussion, and the thesis concludes with presenting a set of guidelines for choosing between these three architecture prototypes for developing a location-based system.

}, keywords = {location-based systems, mobile shadow}, author = {Fischmeister, Sebastian} } @inproceedings {14, title = {Mobile Software Agents for Location-based Systems}, booktitle = {Agent Technologies, Infrastructures, Tools, and Applications for E-Services}, year = {2002}, publisher = {Springer-Verlag Heidelberg}, organization = {Springer-Verlag Heidelberg}, abstract = {

As mobile computing matures, location-awareness as part of context-awareness gains more attention - especially, location-aware services for mobile users. This paper concentrates on the software engineering issues of location-aware services and presents Mobile Shadow as an successful example of a design and an implementation of a scalable, fault tolerant, and component-based service infrastructure for location-aware services. The paper presents the basic concepts used in Mobile Shadow, the requirements, and the resulting component architecture.

}, keywords = {location-based systems, mobile computing, mobile shadow}, isbn = {3-540-00742-3}, url = {http://dl.acm.org/citation.cfm?id=1756350}, author = {Fischmeister, Sebastian}, editor = {R. Kowalczyk and J.P. M{\"u}ller and H. Tianfield and R. Unland} } @inproceedings {20, title = {MUSA-Shadow: Concepts, Implementation, and Sample Applications; A Location-Based Service Supporting Multiple Devices}, booktitle = {Proc. of the TOOLS Pacific}, year = {2002}, month = {February}, publisher = {Australian Computer Society Press}, organization = {Australian Computer Society Press}, address = {Sydney, Australia}, abstract = {

The proliferation of mobile devices has refocused interest on location-information exploiting applications. The most prominent problems are the support of devices with widely varying computing and user interface capabilities and a programming model, which promotes the development of location-based services. The article presents the concepts and implementation of MUSA-Shadow, which addresses both issues through a service infrastructure that provides high-level programming abstraction for the development of location-based applications. Furthermore the system introduces novel concepts for user/service interaction via adaptable event graphs and implicit location information via mobile agents.

}, keywords = {adaptive UI, location-based systems, mobile computing, mobile shadow}, isbn = {0-909925-88-7}, url = {http://dl.acm.org/citation.cfm?id=564103}, author = {Fischmeister, Sebastian and Guido Menkhaus and Wolfgang Pree} }