Response time optimization of composite web services from the perspective of users

Web services technology enables integration of heterogeneous software by encapsulating them into Web services, and building new applications through this way. In addition to the necessary functions, the composite Web services should provide the quality of service (QoS) needed by the users. Response time is one of the important attributes of QoS. The response time of composite Web services is hard to compute because of the loop, conditional selection and concurrent structures in its execution processes. Aiming at composite Web services response time, an optimization method by selecting and invoking appropriate component Web services is proposed in this paper. From user's perspectives, this optimization method considers all the tasks' response time to be executed in one user-waiting-period as a whole when selecting Web services; and according to the different user-sensitivity-levels in the execution process of a composite service, this optimization method adopts different Web services selection schemes to reduce the risk of overtime for critical points in the process. Experiment results show this method effectively optimizes the response time of composite Web services, improves users' satisfaction and services' QoS.EI071179-11882