Scenario-based context-aware service design

Contextual information is becoming available with the increasing deployment of RFID tags, sensor network and mobile devices. The context information regarding user´s environment can be utilized to adapt the behavior of services automatically to user´s situation and need. This kind of adaptive services is called context-aware services. Despite of technological possibility, there is still lack of successful context-aware service. This paper focuses on the methodology of context-aware service design. We first define a formal model of context-aware service based on Petri net. The model is independent of sensor and implementation. Then we propose a methodology of service design including three steps: transforming scenario description into initial service model; constructing context hierarchies and knowledge base; refining model. A conference assistant is designed according to this method.