Context-aware systems behave differently according to the current environment (context) of its users. This context-dependent behaviour is managed by implicit or explicit internal rules. The system observes events in its environment and acts according to its rules. Context-aware systems are thus closely related to event-based systems. Service collaboration is essential for many applications; for example, when using mobile services on hand-held devices. Example services are museums guide systems, navigation systems, and environmental warning systems. A wide variety of context-based and event-based systems are being developed. None of them are explicitely designed to collaborate with other, similar, systems. This talk discusses two approaches to service collaboration, a theoretical and a practical one. First, we introduce an event pattern algebra to compare and combine languages for event-based systems that follow differing semantics. Second, we propose an event-based Service-Oriented Architecture (SOA) for the collaboration of services in the context of a mobile tourist information system.

Bio:Annika Hinze is a Senior Lecturer at the Department of Computer Science, University of Waikato, New Zealand. She is head of the ISDB research group on information systems and databases. Her main research areas are context-aware mobile systems and event-based systems. She is currently visiting Bilkent University.