WebSPN: A Flexible Tool for the Analysis of Non-Markovian Stochastic Petri Nets

Abstract

This chapter describes WebSPN, a modeling tool for the analysis of non-Markovian stochastic Petri nets (NMSPNs). WebSPN is a flexible tool, providing different solution techniques to deal with the complexity of the stochastic process underlying a NMSPN. The first solution technique that was developed within WebSPN is based on a discrete-time approximation of the stochastic behavior of the marking process which enables the analysis of a broad class of NMSPN models with preemptive repeat different (prd), preemptive resume (prs), and preemptive repeat identical (pri) concurrently enabled generally distributed transitions. One of the main drawbacks of the discrete state space expansion approach is the state space explosion that limits the tractability of complex models. For such a reason, a new solution technique has been implemented in the WebSPN tool, which is based on the use of multiterminal multi-valued decision diagram (MTMDD) and Kronecker matrices to store the expanded process. Such a solution works in the continuous time domain and enables the analysis of much more complex NMSPNs with prd and prs concurrently enabled generally distributed transitions. Finally, WebSPN also implements a simulative solution, thus providing a complete and powerful tool for modeling and analysis of real complex systems.