A Framework for Semantic Web Service Discovery and Planning

With the expanse of Internet, Web programmers have wide choice of Web services available to them. A need arises for automatic discovery of required Web services and construction of an appropriate sequence of invocation thereof. In this paper, we present a framework for automation of this task based on currently emerging technologies such as ontological knowledge bases, OWL, OWL-S, WSDL, description logic (DL), etc. Background knowledge ontologies are created based on which semantic meanings of Web services can be given through OWL-S. An agent employs OWL-S API to extract Web service metadata, and applies a DL inference engine, called Racer, for reasoning with the metadata with respect to given background knowledge. Reasoning tasks performed by Racer include profile matchmaking, input/output subsumption testing, and preconditions/effects analysis, which are basic mechanisms for Web services discovery and invocation planning. A prototype system has been implemented