Optimal reliability allocation with minimum cost for Web service composition

By allocating the reliability constraint of the Web service composition to each of component services in the design phase, a service composition with high reliability and low cost could be provided. For this purpose, we first analysis structure patterns of service composition and corresponding failure modes of these patterns are given. Then, a method is proposed to map these failure modes to fault tree. With fault tree analysis method, we obtain the failure function of the service composition. Based on the relationship between the failure rate and the cost of the component services, we design a nonlinear programming model to allocate reliability constraint to component services reasonably. The proposed optimization model can satisfy the reliability constraint of the service composition with minimum cost. We test the effectiveness, practicality and efficiency of the proposed method by extensive experiments.