| Nowadays, many enterprises transfer their core businesses to the Web deployed as Web services. Under such circumstances, how to compose Web services automatically to accomplish complicated functionalities attracts more and more researchers' attentions. In this paper, we focus on the automatic Web Services composition problem based on OWL-S, a Semantic Web Service specification, finding a way enables software Agent to automatically compose existing services to finish user's tasks collaboratively according to user's requirements.We first introduce the state of the art of Web Services Composition, and then analyze the relation between Web Service Composition and related theoretical backgrounds. Concerning the two key technologies, service composition method and service composition system, we demonstrate our work.1. Based on semantic Web Service and OWL-S specification, a first-order logic Situation Calculus planning method for services composition is introduced. The desirable axiom is adopted in Situation Calculus, and the order constructor is adopted in Golog. We discuss the method of translating OWL-S into Situation Calculus axioms, service request profile into goal, and preference rules described by SWRL into desirable axioms. Meanwhile, in the process of services composition planning, we concern the matching problem considering the hidden semantic subsumption relation among the service interface parameters in order to offer more flexibility.2. We put forward a distributed Multi-Agent system for services compostion based on AGORA, which has a good scalability and flexibility and eradicates the problems of low scalability and performance in centrally-controlled services repository. In the system, the service provider and requester can be also searched mutually.In the finality, the problems requiring further studies are discussed. |
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