Design and evaluation of a hybrid physical space service for pervasive computing applications

In this paper we present the design and implementation of a space service that gives pervasive computing applications both a hierarchical and coordinate-based view of physical space. The space service supports both indoor and outdoor campus environments and, besides relational and coordinate space information, it also gives information on how spaces are connected and relevant properties of spaces. We also evaluate the effectiveness of our design using a set of diverse applications, including finding the best "walking" path between two locations, giving walking directions to people, WiFi-based localization, and drawing and annotating maps. We have found that all of our applications depend on both the hierarchical and coordinate views offered by the service, suggesting that the hybrid space model is a very powerful paradigm.