Abstract

In mobile systems, the requirements on composite event detection are fundamentally different to those in distributed systems. Composite event detection must be driven not just by the time of occurrence of an event, but also by its location of occurrence. Hence, the theory of composite event detection, as applied in traditional distributed event-based systems, needs to be reassessed. In this talk, I motivate the need for spatio-temporal reasoning with composite events in mobile systems and introduce SpaTeC, a composite event language that enables simultaneous reasoning over event occurrences in space and time. Composite event operators provide for coarse spatio-temporal reasoning. Spatial and temporal restrictions constrain composite event detection in space and time and provide a basis for event filtering and spatio-temporal routing. Time and location stamps use a guaranteed bounds model for location estimation and time synchronisation. The semantics of SpaTeC event operators is defined accordingly.