Research On Trust Evaluation Model Of Web Service

In recent years, with the development of computer network technology and application, the technology of Web services also developed greatly. With the advantages of easy design, open system, flexible structure and independent of operating system, Web services are used to many websites. As the progress of Web services technology, many Web service examples with the same function have appeared on the Internet, but that can not guarantee each Web service instance is credible. It requires the evaluation of Web services technology to measure the trust of Web services for service users to select high-quality Web services and eliminate low-quality Web services.The main work of the thesis is focused on how to evaluate the trust of Web services. Because of subjectivity, fuzziness and dynamic, the trust of different subject is difficult to be described and tested. So it is necessary to seek new solutions. Being aimed at the features of Web services in the thesis, the trust evaluating models of Web service were studied. The main research contents are listed as follows:Firstly, in order to solve the subjectivity and fuzziness of the trust, the management model of trust and the evaluating model of fuzziness synthesis both based on fuzzy theory were built. The problems of the fuzzy theory modeling for trust and trust evaluating of different subject were solved.Secondly, in order to avoid malicious recommending between different subject, recommendation factor is used. According to two trust vector's matching degree, recommendation factor is updated, which causes the recommendation factor of malicious subject becoming smaller, but the recommendation factor of good intention subject becoming bigger.Lastly, according to some characteristics of Web services, one new trust evaluation model of Web service which is dependent on fuzzy theory is presented. The UDDI is extended and an evaluating module is added in this model. At the same time, the problems of evaluating datum collection and storage are considered in this model, and then the trust of web service was evaluated based on fuzzy theory.