Research On Modeling And Reasoning About Web Services Based On Description Logics

Web services are software-powered resources or self-contained functional components whose capabilities can be accessed over the Internet. Service composition is a means of creating value added web services for SOA.Web services interoperate among different software applications, running on a variety of platforms and frameworks. How to model services for services discovery, composition and checking, is becoming one of the key issues.Our work includes the following aspects: (1) unified domain ontologies are established by ontology matching; (2) a semantic model is proposed to describe both the static and the dynamic aspects using description logic (DL). The static aspect describes the service competence for service discovery; while the dynamic aspect provides the pre- and post-states of the service for behavior checking. (3) The composite services are built over atomic services. Our work is based on a description logics system RacerPro. It uses a decidable fragment of description logic, which is expressive enough for our work.The major contributions can be summarized as follows.(1) A description logics-based ontology matching approach is proposed. Two ontologies are loaded into the DL knowledge base, and the correspondences between elements of them can be produced by reasoning. The data sets FOAM are used to evaluate the performance experiments.(2) A services description semantic model is used to describe the multiple aspects, including IOPEs, Qos etc. of the web services. An algorithm is proposed for service matching by reducing it to match of concepts.(3) A semantic web services modeling approach based on dynamic description logic is represented, which describes the dynamic aspects such as the states of the world and the changes of the world state the services cause. The dynamic aspects are expressed in ABox of knowledge base. The check algorithm for the web services realization is also proposed by using DL reasoning.(4) A semantic model of composite services is built over the model of atomic services, including both static and dynamic aspects, according to the semantic model of atomic services above. The model is presented in knowledge base, which provides the reasoning about the service discovery and behavior checking.