Multilayer Ontology-based Web Services Dynamic Synthesis

Web service composition enables the construction of complex composite services from simpler ones on the Internet according to certain business process logics, thus supporting more powerful and more complete business functions. By dynamically composing existing Web services, there's no necessity to write complex ones from the jump, adapting well to the constant evolution of the e-commerce environment.This paper proposes a complete and well-structured framework for Web service composition. The framework is built on three layers of Ontologies, namely, common sense Ontology, domain Ontology and Web service Ontology. It divides the process of service composition into three steps, which are the generation, specification and implementation of the business process logics, and indicates the importance of service description and discovery mechanisms involved in this process. Based on this framework, current research efforts can be classified into three levels, i.e., automatic composition, dynamic composition and static composition. This paper presents a comprehensive survey of current research work at each level.This paper distinguishes explicitly the concepts of abstract specification and concrete specification of business process logics, and suggests that many existing abstract specifications could be unified into the BPEL4WS language during their instantiation process. BPEL4WS could be considered as a typical concrete specification of business process logics. It has a very strong industry background. This idea makes sense not only to the whole theoretic framework for service composition but also to its practical application in the industry. As an experiment, this paper proposes a new abstract business process logic specification called GBPL, and discusses how to instantiate a GBPL process into a BPEL4WS process. GBPL language brings Ontology technology and executive language's grammar together, thus excelling other similar specifications in many aspects.