SFB 627: Nexus
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SFB 627: Nexus
Project B3:

Location Management and Information Diffusion

Deutsche Version
 
Prof. Dr. rer. nat. Dr. h. c. Kurt Rothermel

University of Stuttgart
Institute of Parallel and Distributed Systems
Universitätsstraße 38
70569 Stuttgart

Tel. +49 (0)711 7816 434
Fax +49 (0)711 7816 424
Kurt.Rothermel@informatik.uni-stuttgart.de


Dr. Christian Becker

University of Stuttgart
Institute of Parallel and Distributed Systems
Universitätsstraße 38
70569 Stuttgart

Tel. +49 (0)711 7816 357
Fax +49 (0)711 7816 424
Christian.Becker@informatik.uni-stuttgart.de


Overview


This project extends the location service concepts that have been developed by the Nexus research team before 2003. As a foundation for the second funding period new algorithms for the management of reduced world models and also for the management of location information in infrastructureless systems are analyzed.

Scalable management of mobile objects is supported by an existing location service, where the mobile objects can currently only be addressed by geographic coordinates. One area of this project deals with extending the location service and the federation service in a way that allows to address objects and regions also by means of symbolic coordinates. For this purpose, topological models are developed, which reflects hierarchical relationsships between areas and which supports addressing mobile objects by using hierarchical names. Region queries and nearest neighborhood queries are realized by the topological model and algorithms based on it. Queries pertaining to static as well as mobile object information are optimized by integrating static object information into the location service. This allows to apply filtering inside the location service already, which decreases management and communication overhead of the federation component significantly. Communication overhead between mobile units and the location service during position updates and queries is reduced by dead reckoning protocols, which yields to decrease in energy consumption of mobile units accordingly.

The second research field of this project focuses on analysing world models in infrastructureless systems. This serves as the basis for the integration of infrastructureless and infrastructure-based systems and as a consequence thereof to the management of hybrid world model structures in the second funding period of the center of excellence. Based on reduced world models it is analyzed which forms of world model management and which algorithms for updating dynamic model information are suitable for pure ad hoc systems. Reduced world models are designed with respect of the captured objects by observations. Based on consistency concepts which are in accordance with the reduced world models algorithms for updating world model information by using variants of the world model management are discussed. Further, information availability, latency and its spatial distribution are investigated. Results of these measurements will influence the design of the location service in mobile ad hoc systems. Important aspects that have to be considered for the management strategies used for location management in ad hoc systems are scalabilty as well as required functionality. As in the case of the infrastructure-based approach, in addition to position, range queries and nearest neighborhood queries need to be supported as well.

Institute


- Institute of Parallel and Distributed Systems    
  Distributed Systems Research Group    


People


- Project Heads    
 - Prof. Dr. rer. nat. Dr. h. c. Kurt Rothermel   
 - Dr. Christian Becker   
- Research Assistants    
 - Dipl.-Inf. Tobias Drosdol   
 - Dipl.-Inf. Dominique Dudkowski   
 - Dipl.-Inf. Ralph Lange