A web services selection and ranking model with QoS constraints

UDDI (Universal description, discovery and integration) specification plays an important role in SOA (Service oriented architecture), but it does not take service selection and rank problem into account, thus can not guarantee the real-time validity of web services responded to service requester. A QoS-guaranteed and distributed mechanism of Web service discovery was proposed, which supports Web service discovery with QoS constraints and is compatible with the UDDI specification. A novel three-dimensional QoS model of Web services was introduced which includes the QoS metrics of the hosting site of Web services, Web services, and method of Web services, and a Web service selection algorithm was designed. The concept and measure method of Web service effectiveness were proposed, then a Web service ranking algorithm based on the effectiveness of Web service was designed. Furthermore, a prototype was implemented and used by the national geology grid project. The comprehensive experiment shows the new model possesses high precision, high response rate and better influence on the load balance of Web service.