Extended Reachability Graph of Petri Net for Cost Estimation

Reachability graph is a fundamental tool for analysis of Petri Net models of discrete event dynamic systems. However, the applicability of reachability graph is limited to finding different states that are reachable from an initial state. This paper presents a new extended reachability graph that is much more useful: the extended reachability graph can be used for not only finding the states that are reachable from an initial state, but also how much these states will costs. In order to support the new extended reachability graph, this paper also proposes an extension to the timeless ordinary Petri Net, for incorporating firing times and firing costs of transition firings. In this paper, firstly, an extension to the ordinary Petri Net is proposed. Secondly, based on the extended Petri Net, an extended reachability graph is presented. Finally, an application example is also given on the cost estimation of a software development project.