摘要：Web service based applications have been widely applied in various kinds of domains with the development of service-oriented architecture. However, service selection and composition under user’s QoS constraints still remains to be a challenging issue because of the changing of user’s requirements. In this work, we present a QoS-oriented web service framework and its implementation, which is aiming to optimize the performance of service-based application with constraints to user’s QoS requirements. In this framework, the optimum mapping between abstract web services and application’s processes is implemented through mixed programming technique. In addition, an embedded QoS negotiation mechanism is also implemented in this framework for refining the execution of service-based application at runtime. Massive experiments based on real workloads are performed to evaluate the effectiveness of the proposed framework in both static environment and dynamical environment. The results indicate that the proposed framework and its service selection/composition algorithm can significantly improve the user’s QoS satisfaction in terms of five most-mentioned QoS parameters.
关键词：service selection;mixed programming;workflow;heterogeneous systems
