An Efficient Service Substitution Algorithm Based on Temporal Composite Behavior Graph

Web services can be composed together and interact with each other to carry out complex transactions or workflows. During the execution of an autonomic process, if one component service fails or becomes overloaded, a mechanism is needed to ensure that the running process is not interrupted and the failed service is quickly and efficiently replaced. This paper presents a novel Web services replacement pattern called composite behavior pattern with temporal. The existing model of substitution does not consider the life cycle of services and EQoS (executive QoS) value along with environmental changing. Consequently, some discovered candidate behavior patterns may be invalid while some useful behavior patterns may not be covered. To overcome this drawback, in this paper, we take into account the life cycle of Web services and temporal composite behavior pattern matching. We introduce an efficient Web service substitution algorithm, DESA (bi-direction extended search algorithm)which significantly reduces hybrid (forward extended after backward extended) search space and results in near optimal solutions. Our experimental results demonstrated the efficiency and effectiveness of the proposed algorithm.