Abstract

Location is a primary cue in many context-aware computing systems, and is often represented as a global coordinate, room number, or a set of Euclidean distances to various landmarks. A user's concept of location, however, is often defined in terms of regions in which similar activities occur. We discuss the concept of such regions, which we call activity zones, and suggest that such zones can be used to trigger application actions, retrieve information based on previous context, and present information to users. We show how to semi-automatically partition a space into activity zones based on patterns of observed user location and motion. We describe our system and two implemented example applications whose behavior is controlled by users' entry, exit, and presence in the zones.