Abstract:

In view of the extended Web service architecture, we formally modeled the Web service composition with probabilistic timed automata (PTA). The process of Web service composition was understood as a realtime system operation process. We then overcame the limitation of existing research approach of Web service quality which focused the service quality on a single Web service, by quantitatively analyze the quality of Web service composition on the basis of the model we built before. The stochastic and nondeterministic characteristics in the execution of Web service composition were fully taken into account in the whole analysis so as to make the result credible. Finally, an example was given to illustrate the feasibility of the modeling analysis method, proving that
 the corresponding service selection strategy can improve the success probability of Web service composition.

Key words: Web service composition, probabilistic timed automata, quantitative modeling analysis, quality of Web service