Using Event B to Specify Context Awareness for Service Discovery in Pervasive Environments

The environments of pervasive computing are open and dynamic. In order to ensure the dynamic discovery of services evolving in a heterogeneous and dynamic environment, specific extensions to WSDL, known as A-WSDL are suggested. These extensions permit to a service provider to define the context of service use and the behavior associated to each change of context. To verify and prove the expected behavior of the suggested discovery protocol in the design phase, the Event-B formalism is adopted. One of the advantages of the Event B formalism is the application of the refining techniques which permit to express complex features by means of mathematical proofs and moves from an abstract specification to a concrete specification by using the Rodin tool which offers a support for the refining and the proofs.