Résumé en anglais

In order to check formulas with rewards on multidimensional Continuous Time Markov Chains (CTMC) for composite Web service model, we propose an algorithm based on stochastic comparison. The considered model has heterogeneous servers and the number of elementary Web services can be very large. Thus, the computation of the rewards on the exact model is almost impossible because of the well known problem of the state space explosion. We propose to apply our proposed model checking algorithm on our proposed bounding models in order to perform the verification on the bounds values instead of the exact one. These bounding models provide upper and lower bounds on response times of composite Web service model.