Web服务组合中基于服务质量的服务选择算法

Service Selection Algorithm Based on Quality of Service and Its Implementation for Web Services Composition

为了提供满足客户服务质量(QoS)需求的组合Web服务,提出了一种支持QoS属性描述的Web服务描述模型.通过在原有的Web服务描述语言的tport元素中添加operationInst属性来描述QoS属性,从而获得了一种可扩展的Web服务描述语言.在此基础上给出了基于多目标决策理论和分形理论的服务选择算法,该算法考虑了QoS属性之间的不可公度性和独立性,同时给出了QoS驱动的服务组合框架(E-WsFrames)和具体实现方法.实验结果分析表明,E-WsFrame可以综合考虑服务组合的功能和QoS的要求,并可根据服务请求自动地实现组合服务.

In order to provide composite Web services according to the quatity of service（QoS） requirements of clients, a Web service description model was proposed to support the QoS descriptions. In addition, the attribute of QoS was described by adding the operationInst attribute to the tport element of the original Web service description language （WSDL）, a services selection algorithm was provided in terms thereby obtaining an extendable WSDL, upon which of the multiple attribute decision-making and fractal theory. The incommensurability and independence among QoS attributes were considered in the algorithm, meanwhile the composite workframe E-WsFrame of QoS driven service and its complementation were given The experiments and analysis results demonstrate that E-WsFrame can synthetically ensure both of the composite service functions and QoS requirements, and carry out composite service automatically according to requests.