Using Semantic Policies to Reason over User Availability

According to the IETF definition, "presence conveys the ability and willingness of a user to communicate across a set of devices". In this paper we use semantic techniques to ask and reason about this ability and willingness on the basis of local context, instead of conveying raw context data. We describe the architecture of a policy engine, using the N3 language, give policy examples and discuss the applicability of the techniques in small, mobile terminals.