Quality Driven Web Services Composition Based on an Extended Layered Graph

Service composition becomes the most interesting challenges in the Web services area. In this paper, the quality of service (QoS)-aware composition of Web services is discussed. In the existing work, heuristic or intelligent optimal algorithms are adopted directly upon the complex process model of a composite service, which means different flow constructs (e.g. sequence, selective, simultaneous, combination, and circle) have to be considered during composition, adding up to the complexity of the algorithm and decreasing the efficiency. Here, we present a lightweight extended layered graph based (LELGB) model to take the place of the complex process model. By using LELGB model, the problem can be reduced into a routing problem in a directed graph. Experiment results show that this model is feasible and effective.