A Stochastic Performance Model Supporting Time and Non-time QoS Matrices for Web Service Composition

In recently years, Web service composition becomes a new approach to overcome many difficult problems confronted by B2B e-commerce, inter-organization workflow management, enterprise application integration etc. Due to the uncertainty of the Internet and various Web services, the performance of the composed Web service can not be ensured. How to model and predict the performance of the composed Web service is a difficult problem in the Web service composition. A novel simulation model that can model and simulate time and non-time performance characters, called STPM⁺, is presented in this paper. Based on Petri net, the STPM⁺ model can simulate and predict multiple performance characters, such as the cost, the reliability and the reputation of the composed Web service etc. To examine the validation of the STMP⁺ model, a visual performance evaluation tool, called VisualWSCPE, has been implemented. Besides, some simulation experiments have been fulfilled based on VisualWSCPE. The experiment results demonstrate the feasibility and efficiency of the STPM⁺ model.