Realms and States: A Framework for Context Aware Mobile Computing

Location and other spatio-temporal attributes are important in mobile and context aware computing. We propose a new model for location and new abstractions in support of location and context awareness. We present a unified model of raw location, and introduce the concepts of spatial realms and spatial states, which support higher level concepts of location. We show how key application requirements including naming, privacy, scalability and ease of administration are supported. The theory of realms and states, including some notions of distance, and necessary location service primitives are described. We then propose a generalized concept of realms and states, with the goal of providing unifying abstractions for spatio-temporal context. We claim that this enables richer applications to be written using the same set of abstractions.