Modeling and Evaluation of Composite Web Services Based on Generalized Stochastic Petri Net
Zhenhua Duan · Xi'an Jiaotong Daxue xuebao · 2008
To ensure the correctness of composite Web services described by semantic Web services markup language(OWL-S),and to guarantee the high performance of the composite Web services,a generalized stochastic Petri net based method is proposed for modeling,verification and evaluation of the OWL-S process models.The transforming rules from OWL-S process models to generalized stochastic Petri net(GSPN) are given.The analysis of S-invariant,T-invariant and reachability of the Petri net are used to verify the soundness of the process models.Moreover,Markov chains of the models are constructed.Performances of the processes are analyzed in terms of steady state probability distribution of generalized stochastic Petri net.It is verified mathematically that the models are correct and reliable.Also the bottlenecks of composite Web services is found.It is believed that the method will support to the reconstruction,optimization and decision-making of the composite Web services.