Analyzing Reliability of Time Constrained Service Composition

As a way to compose independent services together to fulfill a function, service composition is an important means for flexible and rapid information integration of complex distribution application in open and heterogeneous environment. Because the participating services may be failure or unavailable, how to guarantee the quality of service composition has become a challenging problem. A service composition model based on Timed Petri net (SCTPN) is proposed in this paper, which is capable of accurately capturing transaction behaviors and time constraints of services. The basic relationships and failure processing strategies between services are also characterized by SCTPN model. Based on states of the constructed SCTPN model, we propose the concepts of greatest concurrent set and transfer matrix to analyze reliability related properties of SCTPN model. Two simplification schemas are established to reduce the complexity of computation. Finally, three specific experiments are conducted to explain the effectiveness of proposed method.