On the Semantics of Functional Descriptions of Web Services

摘要

Functional descriptions are a central pillar of Semantic Web services. Disregarding details on how to invoke and consume the service, they shall provide a black box description for determining the usability of a Web service for some request or usage scenario with respect to the provided functionality. The creation of sophisticated semantic matchmaking techniques as well as exposition of their correctness requires clear and unambiguous semantics of functional descriptions. As existing description frameworks like OWL-S and WSMO lack in this respect, this paper presents so-called Abstract State Spaces as a rich and language independent model of Web services and the world they act in. This allows giving a precise mathematical definition of the concept of Web Service and the semantics of functional descriptions. Finally, we demonstrate the benefit of applying such a model by means of a concrete use case: the semantic analysis of functional descriptions which allows to detect certain (un)desired semantic properties of functional descriptions. As a side effect, semantic analysis based on our formal model allows us to gain a formal understanding and insight in matching of functional descriptions during Web service discovery.