Delta-reasoner: a semantic web reasoner for an intelligent mobile platform.

To make mobile device applications more intelligent, one can combine the information obtained via device sensors with background knowledge in order to deduce the user's current context, and then use this context to adapt the application's behaviour to the user's needs. In this paper we describe Delta-Reasoner, a key component of the Intelligent Mobile Platform (IMP), which was designed to support context-aware applications running on mobile devices. Context-aware applications and the mobile platform impose unusual requirements on the reasoner, which we have met by incorporating advanced features such as incremental reasoning and continuous query evaluation into our reasoner. Although we have so far been able to conduct only a very preliminary performance evaluation, our results are very encouraging: our reasoner exhibits sub-second response time on ontologies whose size significantly exceeds the size of the ontologies used in the IMP.