A Trustworthy Web Service Composition Approach Based On QoS

The rapid development of the Internet and computer technology also brings the rapid development and application of the Web services technology, which make the number and functions of the current Web services increase quickly. However, the function of a single atomic service is limited, and the needs of users are complex and changeable. Therefore, how to combine the existing services fast, accurately and efficiently to achieve the seamless integration between services, to improve the utilization of atomic service and to provide Web services with quality assurance to meet the growing needs of users becomes a serious problem.The occurrence of Web services and composite services with various functions brings a great convenience for people. As the increasing high demand for Web services, there are some urgent problems to be solved. For example, the high-quality atomic services cannot guarantee the quality of the composite services is high. Therefore, the researchers expected to explore a set of methods to ensure the quality of service composition through the study on the non-functional property of Web services such as QoS. However, since users'needs are vague and the environment of the service is dynamic, the simple and mechanical comparison of the sizes of QoS cannot guarantee the quality of services. For instance, in an open network environment, the service providers may also provide the unreal QoS service. Then, the high-quality QoS of service doesn't guarantee the service is trustworthy, which means the service cannot always be reliable. As for this situation, based on the research of QoS, this paper introduces the concept of trustworthy Web service to study the trustworthy problem of Web service composition.The work of this thesis mainly includes the following aspects:1. Present the Trust Web Service Composition Model-TWSCMBased on the existing research of QoS, this paper introduces the concept of trustworthy Web service to study the trustworthy problem of Web service composition. And the TWSCM is presented, that is, add QoS agent and the trust module on the original Web services architecture and guarantee the quality of composite services through the trust module.2. Propose the trustworthy assessment method of Web service compositionAccording to the proposed TWSCM, we assess the trustworthy of the service composition. Through the selection of the properties of the service quality QoS, and the discussion of the QoS measurement method of the atomic services and the composite services, the QoS trustworthy and its stability as well as the feedback of the users are introduced to assess the trustworthy of the composite services. Finally, apply the reinforcement learning of the trustworthy measurement to ensure the recommended composite services are trustworthy.3. Design the experiment taking the language service as an exampleOn the multi-cultural cooperation and exchanging platform-language grid, carry out the related experiments taking the language service as an example. Verify the feasibility and effectiveness of the proposed model and method through the experiment.