Generalized semantics-based service composition

Abstract. Web services and Service-oriented computing is being widely used and accepted. In order to effectively reuse existing services, we need to automat-ically compose Web services. The automatic composition techniques need to be semantics-based rather than syntax-based, since only semantics can accurately capture the task a service performs. In this paper we present general semantics-based techniques for automatic service composition for Web services. Our gen-eral method takes as input (i) a repository, R, of semantic descriptions of Web ser-vices, (ii) a semantic description, Q, of the service that is desired, and produces a composite service consisting of services taken from R that realizes Q. The com-posite service may combine services linearly as a chain or as a directed acyclic graph, where in the most general case the combination may be conditional. The composite service generated by our automatic composition method can be coded as an OWL-S document. We present details of our initial implementation along with performance results.