Extracting Petri Modules From Large and Legacy Petri Net Models

Abstract

Petri nets, even though very useful for modeling of discrete event systems, suffer from some weaknesses such as huge size, huge state space, and slow in simulation. Due to the huge state space, model checking a Petri net is difficult. Also, due to the slowness in simulation, discrete-timed Petri nets cannot be used for real-time applications. Thus, modular Petri nets are suggested as a way of overcoming these difficulties. In modular Petri nets, modules are designed, developed, and run independently, and the modules communicate with each other via inter-modular connectors. This approach is suggested for developing newer Petri net models. However, there exists a large number of Petri net models of real-life systems, and these legacy models are enormous and non-modular. And, these models cannot be discarded as large amounts of time and money were spent to develop these models. This paper presents a unique algorithm for extracting modules from large and legacy Petri net models. The algorithm extracts modules (known as "Petri modules") that are well-defined for inter-modular collaboration. Also, the extraction method preserves the structural properties. The goal of the paper is to introduce a methodology by which Petri nets can be moved to a new level in which a modular Petri net model can be made of Petri modules. The Petri modules are independent and can be hosted on different computers. These modules communicate via inter-modular components such as TCP/IP sockets. Since Petri modules are compact, also run faster, thus become suitable for supervisory control of real-time systems.

Understanding the Importance of Efficient Visitor Flow Within Tokyo Skytree

“…GPenSIM supports modular model building, which is inevitable for modeling large real-life discrete-event systems [16], [17]. GPenSIM proposes the use of "Petri Modules" for developing large Petri Net models [16] [17].…”

A reliability evaluation method for complex systems based on the editable GSPN and adaptive Monte Carlo simulation

“…Ref. 9 proposed a method for extracting modules from large and legacy PN models, but inter‐dependence between subsystems complicates the extracting process.…”

Optimal Supervisory Control for Flexible Manufacturing Systems Model With Petri Nets: A Place-Transition Control

“…Control places are used in the works of [1]- [17], [35], [36] to enforce certain constraints that satisfied a specified set of VOLUME 4, 2016 instructions, to restrict the firing of transitions that lead the systems to deadlock zone. Ghaffari developed the theory of regions in [19] for optimal supervisors using control places to realize the desired behavior.…”

“…The method provides the liveness of the PNM when all the control places are added but cannot ensure the optimal solution of the controlled PNM. In all the methods review [1]- [4], [15]- [17], [19]- [22] have used the control places in the supervisor, which characterized with high restriction on reachable states of the PNM. This implies that too much use of control places in the supervisor may lose concurrent systems properties for FMSs.…”