Description
Web services and Service-Oriented Computing is being widely adopted. In order to effectively reuse existing services, we need an infrastructure that allows users and applications to discover, deploy, compose, and synthesize services automatically. This automation can take place only if a formal description of the Web services is available. In this article we present an infrastructure using USDL (Universal Service-Semantics Description Language), a language for formally describing the semantics of Web services. USDL is based on the Web Ontology Language (OWL) and employs WordNet as a common basis for understanding the meaning of services. USDL can be regarded as formal service documentation that will allow sophisticated conceptual modeling and searching of available Web services, automated service composition, and other forms of automated service integration. A theory of service substitution using USDL is presented. The rationale behind the design of USDL along with its formal specification in OWL is presented with examples. We also compare USDL with other approaches like OWL-S, WSDL-S, and WSML and show that USDL is complementary to these approaches.