Verifying OWL-S Service Process Models

OWL-S is an ontology that provides the necessary vocabulary for describing various components of Web services so that automated discovery, composition and invocation of Web services can be made possible. The main component, the process model, describes the interaction protocol between a Web service and its clients. Such protocol includes not only the inputs, outputs, preconditions and results of the service, but also the control flow and data flow within the service. In this paper, we propose an approach to verify various properties of the process model of an OWL-S service. We define a set of mapping rules to translate a process model into a process algebra model and use a dedicated model checker to check the properties of the translated model. We handle not only the control flow of the process model, but also the binding-based data flow. Pre-conditions and results are also included in our approach. As a case study, we use a reasonably complex online book shopping Web service.