Research On The User Requirement-Driven Composition Of Semantic Web Services

Web services composition is a hot issue in the research domain of service-oriented computing. It produces value added and more complex services, by reusing those existing lightweight services. So it can satisfy the higher application request. User requirement-driven composition of Web services can compose Web services dynamically based on the requirements given by users temporarily. There are mainly two kinds of user requirement: functional requirement and non-functional requirement. Correspondingly, semantic information and QoS are two key problems in the procedure of composing.Firstly, user requirements and Web services are described formally. Then, based on the initialization conditions and goal outputs given by user, a semantic-based strategy is used to select the proper component services. The important thing is that the result can satisfy user's functional requirements. This work presents a composition method based on weighted dependency graph. This method improves the success rate and the correctness of the composition result. For the non-functional requirement, a component service selection strategy based on QoS is presented. This strategy combines the Local Optimum strategy and the Critical Path Method. Firstly, it generates the initial solution, then, checks the validity of the solution by CPM. If the solution is not valid, then adjust the solution properly. This strategy takes fully into account the QoS requirement of user and the efficiency of the selection. At last, a user requirement-driven web service composition system framework is designed. After obtaining the description of requirements, it uses the proposed method to produce the composition plan instantly.This paper focuses on the research of the user requirement-driven composition of semantic Web services, including the generation of the composite service process and component services selection method based on QoS constraints. This paper makes an effective solution and a contribution to the theory research on the technology of Web services composition.