Research On The Instant Task-Solve-Oriented Composition Of Semantic Web Services

Web services composition produces value added services satisfying the higher request of users by reusing services of simple structure and function. Semantic web technology makes web service to be an understanded entity of computer. So it makes automatic matching and automatic composition become true. The instant task-solve-oriented composition of web services can compose web services instantly and automatically based on the requirements given by users temporarily.User requirements include functional requirements and non-functional requirements. So, Semantic information of service, quality of composite service, efficiency and success rate of composition are key problems in the procedure of composing.For the functional requirements, this work presents a composition method based on service and parameter relation graph. It matches the parameters based on semantic similarity between concepts. Firstly, from the input request of user, it constructs an directed acyclic hierarchical service and parameter relation graph with the shortest time-step. And then defines a satisfaction control the efficiency and quality of composition.It searches for a solution to meet the satisfaction and requirements from back to front in the relation graph. This method improves the success rate of composition.For the non-functional requirements, a service selection method based on user QoS requirements is presented. This method firstly generates a local optimum initial instance which meet the local constraints. And then adjusts the initial instance according to user expectations. This method takes into account user preferences, user local demands and global demands for composite service. It has high efficiency.This paper focuses on the research of the instant task-solve-oriented composition of web services, including the generation of the composite service based on graph and service 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.