A dynamic web services selection based on decomposition of global QoS constraints

The objective of web services selection is to maximize an application-specific utility function under the end-to-end QoS constraints. Existing methods can be divided into two types: local selection method and global selection method. The local selection method is simple and efficient, but can not meet the end-to-end QoS constraints. The global selection method can satisfy the global QoS constraints, but at the price of higher computational time, and it is not suitable for the dynamic environment. To address this issue, this paper proposes an algorithm to combine global QoS constraints with local selection, which first splits the global QoS constraints into local constraints using heuristic method, and then uses local selection to find the optimal solution under the local constraints. The experimental results show that our approach improves the performance by reducing the computation time greatly while achieving close-to-optimal results.