Research And Implementation Of Web Service Composition Scoring Method

Through standard Web protocols Web services to provide services with users, and convert Web applications’information interaction into service interaction in network, through interactive architecture among the service consumers, service providers and service registries to complete service search, publish and access. With the rapid development of Internet and e-commerce, the service process between users and the enterprises and between enterprises become increasingly complex. In order to complete the service demand which the user will and to get some new features need to combine a lot of service; therefore service providers can provide higher quality of service to users, so this is the concept of service composition in Web services. That new service is called the composite service, that combination construction of composite service is called component services.In order to obtain greater benefits, service providers tend to publish false information about service quality to that service user, because of information asymmetry, meanwhile, the user cannot get real information about service that accessed, to the extent that suffer great damage. Therefore the research about Web service reputation issues received attention related researchers in the Web service research, and because the feedback scores of Web service obtained from customer is the foundation of the Web service reputational measure, research the user feedback score is very important for Web service. In that the implementation detail of the Web service is transparent to the service user and the service user cannot distinguish a service which used is a composite service or a component service. The service user will give a service score to the service provider according the overall performance of service after service invocation, and if that service is a composite service that contains multiple component service, in order to determine the performance of each component service, so we need to distribute that feedback score to each component services. Therefore, study of composite service score distribution method about Web service is very important.Firstly, this article do a detailed description for the problem of the Web service composition score distribute, and then propose a definition of fair score distribution, and use that definition as the conditions to study score distribution method. In order to distribute the score of composite service obtained from customer to each component service based on actual and historical performance of component services, first of all the Web service process will be converted into structure tree process, analytic hierarchy process(AHP) was used to calculate the distribute weights of each component service, in addition the relationship between actual QoS of component services and its advertised utility interval of QoS were taken into consideration, and through that QoS to calculate each component service deviation function, meanwhile the influence on distribute score by history performance of each component services were considered, and comprehensive above value to calculate the score of component services. Experiment results showed that score distribute method of composite service about Web service in this paper has a good reasonableness and fairness, and good to meet the conditions of a fair distribution of this article mentioned. Finally, designed a prototype system to support Web service score distribute method, and this prototype system is use C/S structure, and using the Java language to develop. The system, firstly, requires the user to load the Web workflow process from the service library, and then convert the service process which loaded into the system to structure tree process, based on an analysis of information out of the structure tree, get the number of component service, and then load QoS values of each component to calculate, get the score of every component service which be distributed.