Research On QoS Model In Web Services

Web services is a new and emerging Internet technology, which supports cross-platform application, cross-language development and service oriented application integration. At present, Web services has already become a dominant framework design for distributed applications in government, finance, telecommunications, securities, education and service industry, and other fields. As a wide range of applications based on Web service technology is adopted, there are a large number of Web Services with the same or similar function appeared. Due to the lack of QoS (Quality of Service) support for current Web Service standards and technologies, how to select the most proper services with a better quality service level from the candidates has become an urgent issue.Building a Web services'QoS model is to use mathematical modeling method to describe and evaluate QoS level for Web service, analyze service request information and make prediction on the quality of unused services based on historical QoS data, thus providing quality of service support for searching and screening services in Web service network. Based on the existing Web service system structure, in order to overcome the insufficiency in data processing for traditional QoS model, we propose a trust Web service QoS evaluation model, which combines both the subjective and objective influence QoS factors to make a comprehensive and robust QoS evaluation.The main works of this paper are described as follows.1.QoS related technology and the analysis about the restriction factor of popularity for Web service is extensively introduced, full expression of Web service's QoS factors is made, quality of service evaluation model adapt for Web service is classified and studied.2.Based on the support of agent based Web service framework, a further improvement is made on Web service system structure, a flexible and efficient QoS information collection mechanism is proposed, the new structure can update the initial published QoS data dynamically according to the feedbacks from service consumer3. An original QoS model combining both subjective and objective QoS factors is made to realize support QoS in Web service network without making any changes on existing standards or implementation technology. The flexible and extensible Web service QoS evaluation algorithm has good safety and high efficiency, and effectively screen baleful evaluation feedback.