(1999) Kubach, Uwe; Leonhardi, Alexander; Rothermel, Kurt; Schwehm, Markus
New applications in the area of mobile computing make heavy use of knowledge about the application's run-time environment. Applications running on mobile devices in particular exploit knowledge about their current geographical position or query for the location of other interesting objects. To manage such queries some applications provide a location service specifically tailored for their needs. The efficient and application-independent handling of such queries calls for a global and universal location service. Considering a large number of users and queries to be handled, a distributed implementation of a location service is necessary. This paper analyses three schemes for the partitioning of location information and derives a performance model for these partitioning schemes. Finally, an example for the application of the analysis' results is presented for a universal location service within the Nexus system, an infrastructure for location aware mobile computing.
Due to the lack of a generic platform for location- and spatial-aware systems, many basic services have to be reimplemented in each application that uses spatial-awareness. A cooperation among different applications is also difficult to achieve without a common platform. In this paper we present a platform that solves these problems. It provides an infrastructure that is based on computer models of regions of the physical world, which are augmented by virtual objects. We show how virtual objects make the integration of existing information systems and services in spatial-aware systems easier. Furthermore, our platform supports interactions between the computer models and the real world and integrates single models in a global 'Augmented World'.
