Based On The Dynamic Semantics Of Web Service Description

Currently the semantic web is combined with the web services technologies to describe services in an unambiguous and machine interpretable way. Thus, semantic reasoning techniques can be used to support automated Web service discovery, invocation and composition of web services.However, the current web service description languages proposed by academic and industrial researchers for specification of Web service all suffer from the lack of their ability to provide constructs and concepts that enable reasoning about service behavior and character temporal properties of web service. Complex Web services and their compositions are often long lived processes that extend beyond single step execution, they maintain an ongoing interaction with requestor or other Web services, continuously act according the intermediate state. When describing such systems the focus is not just on what is computed in term of given inputs but equally on how it is computed, i.e., in terms of interaction capabilities over periodic of time during which intermediate states could be critical decision making stages. Specification of services should include assertions that not only validate their initial state, but also their intermediate states.In order to ensure the success of various tasks involving web services such as discovery, composition, planning, a language is required for richer specification of web service so as to faithfully describe both static domain knowledge and dynamic aspect of function of web service ,such as state changes caused by web services,temporal properties that should be followed by web services. The language provides the semantic basis for Web service discovery and composition.In this paper, we propose a framework to support rich service description and reasoning.Firstly, to overcome the insufficiency we propose a Semantic Web service description language OWL—DS which are an extension of OWL-S .to describe dynamic semantic of web services behavior. The properties predicates pre, post in OWL-DS are used to describe state change caused by web services. These properties predicates are specified in a declarative form and integrated with process model of OWL-S. Three basic reasoning services are proposed: Executability, Projection, and Process Consistence. OWL—DS can describe both static and dynamic semantic of web services. Secondly, Based on OWL-DS, a new semantic matching technique is proposed and some degree of semantic matching are defined. The matching techniques provide the basis for Web service discovery and composition. Especially, technique reasoning task of semantic matching can be reduced to basic reasoning problem of traditional description logic, so it enables available efficiency description logic system to be exploited for reasoning about web servicesThirdly, Further, we augment OWL-S process model with temporal properties formally called Assumption and Commitment and get a new description language OWL—TDS. The properties predicates pre, post in OWL-TDS are used to describe state change caused by web services while Assumption, Commitment are used to describe ongoing aspects of web servicesWe investigate translation from OWL-TDS into logic programming, in which input, output, Preconditions, Assumption, Effects, Commitment all can be naturally expressed in the form of rules. there translation serve as a basis for the use of systems for computing answer set for reasoning in semantic web services domains. It enables available efficiency LP inference implementation such as SMODEL,DLV to be exploited for reasoning about web services. Thus , the formalism provides a powerful techniques for reasoning about services discovering and composition。...