Abstract: In QoS-guaranteed composite Web service selection, it is difficult to obtain the accurate measurements of QoS. Meanwhile, users’ QoS requirements are hard to describe. To address these concerns, a novel method of Web services selection is proposed. It uses interval numbers to describe users’ QoS requirements and QoS parameters of Web services, and introduces user satisfaction degree to evaluate the composite services. Base on a Particle Swarm Optimization with Dynamic Boundary (DBPSO), the method tries to find appropriate composite service that meets the global QoS requirements of users. Simulation results have shown that the proposed method is both feasible and effective.

Key words: Web service selection, Uncertain information, Quality of service, Dynamic boundary, Particle Swarm Optimization