Generalized Conditions for Liveness Enforcement and Deadlock Prevention in Petri Nets (original) (raw)

On the Equivalence Between Liveness and Deadlock-Freeness in Petri Nets

Lecture Notes in Computer Science, 2005

This volume contains the proceedings of the 26th International Conference on Application and Theory of Petri Nets and Other Models of Concurrency (ICATPN 2005). The Petri net conferences serve to discuss yearly progress in the field of Petri nets and related models of concurrency, and to foster new advances in the application and theory of Petri nets. The conferences typically have 100-150 participants, one third from industry and the others from universities and research institutions, and they always take place in the last week of June. Successive editions of the conference are coordinated by the Steering Committee, whose members are listed on the next page, which also supervises several other activities-see the Petri Nets World at the URL www.daimi.au.dk/PetriNets.

T-Liveness Enforcement in Petri Nets Based on Structural Net Properties

2001

We introduce a semidecidable procedure which, given a Petri net structure and a set T of transitions, synthesizes a supervisor enforcing the transitions in T to be live. We call this liveness property T -liveness. When T equals the total set of Petri net transitions, T -liveness corresponds to liveness. Enforcing only a subset of transitions to be live is useful when some Petri net transitions model undesired events such as failures, and/or when the Petri net structure does not allow enforcing all transitions to be live. Our procedure is based on structural net properties, and so the synthesized supervisors are independent of the initial marking. The supervisors are least restrictive for a wide class of Petri nets. No assumptions are made on the Petri net structure: the Petri nets may be unbounded and have integer weights. In this paper we restrict our attention to fully controllable and observable Petri nets. However we note that the procedure is rather easily extendable to Petri n...

Tscr;liveness enforcement in Petri nets based on structural net properties

2001

We introduce a semi-decidable procedure which, given a Petri net structure and a set 𝒯 of transitions, synthesizes a supervisor enforcing the transitions in 𝒯 to be live. We call this liveness property 𝒯-liveness. When 𝒯 equals the total set of Petri net transitions, 𝒯-liveness corresponds to liveness. Enforcing only a subset of transitions to be live is useful when some Petri net transitions model undesired events such as failures, and/or when the Petri net structure does not allow enforcing all transitions to be live. The supervisors generated by our procedure are often least restrictive, and their synthesis is independent of the initial marking. No assumptions are made on the Petri net structure: the Petri nets may be unbounded and have integer weights. We have extended the procedure to Petri nets having uncontrollable and unobservable transitions, however, in this paper we restrict our attention to fully controllable and observable Petri nets

Optimal liveness-enforcing control for a class of Petri nets arising in multithreaded software

2013

Abstract We investigate the synthesis of optimal livenessenforcing control policies for Gadara nets, a special class of Petri nets that arises in the modeling of the execution of multithreaded computer programs for the purpose of deadlock avoidance. We consider maximal permissiveness as the notion of optimality. Deadlock-freeness of a multithreaded program corresponds to liveness of its Gadara net model.

On Liveness and a Class of Generalized Petri Nets

IEEE 2017 8th Annual Industrial Automation and Electromechanical Engineering Conference (IEMECON), Bangkok, Thailand, 2017

Petri nets prepare an effective method of computing minimal siphons and elementary siphons based on the concept of initial resource assignment on liveness for the class of generalized Petri nets, namely S 4 PR. At the point when consideration concentrates on the utilization of framework assets flexible manufacturing systems (FMS) can be viewed as an exceptional class of simultaneous resource allocation systems (RΑЅ). A siphon is specified with the liveness properties of Petri net (PN) models of FMS. These connections are solid and strong in the case of (RASs). Structured and formalized modeling methods of the siphon computation problem with an S 4 PR net are a typical class of PN. The exceptional linguistic limitations of a few classes of RASs can help in creating particular calculations to process guides in a more effective manner. A Petri net is a tool for deadlock problems specifying and analyzing concurrent systems in which control minimal siphons appeared in the main parameter for the model and control of FMS. An enumeration method is given for analyzing the structural Petri net's behavior. This new method, which allows for formal verifying siphons-based systems, is simulated as an illustrative example of the specification and verification of a simple manufactured.

On Liveness Enforcement of Distributed Petri Net Systems

ArXiv, 2020

This paper considers the liveness enforcement problem in a class of Petri nets (PNs) modeling distributed systems called Synchronized Sequential Processes (SSP). This class of PNs is defined as a set of mono-marked state machines (sequential machines, called also agents) cooperating in a distributed way through buffers. These buffers could model intermediate products in a production system or information channel in a healthcare system but they should be destination private to an agent. The designed controller for liveness enforcement should preserve this important property characteristic to the distributed systems. The approach in this paper is based on the construction of a control PN that is an abstraction of the relations of the T-semiflows and buffers. The control PN will evolve in parallel with the system, avoiding the firing of transitions that may lead the system to livelock. An algorithm to compute this control PN is presented. Moreover, in order to ensure the liveness of co...

Deadlock analysis and control based on Petri nets: A siphon approach review

Advances in Mechanical Engineering, 2017

Deadlocks should be eliminated in highly automated manufacturing systems since their occurrence implies the stoppage of the whole or partial system operation. Over the past decades, Petri nets are increasingly becoming one of the most popular and full-fledged mathematical tools to deal with deadlock problems due to their inherent characteristics. In a Petri net formalism, liveness is an important property of system safeness, which implies the absence of global and local deadlock situations in an automated manufacturing system. The liveness assessment can be performed by verifying the satisfiability of certain predicates on siphons, a well-known structural object in Petri nets. Therefore, siphons have received much attention to analyze and control systems modeled with Petri nets. Particularly, elementary siphon theory plays a key role in the development of structurally simple liveness-enforcing Petri net supervisors, leading to a variety of deadlock control approaches. This survey studies on the state-of-the-art elementary siphon theory of Petri nets including refined concepts of elementary siphons and their extended version, computation methods of siphons and elementary ones, controllability conditions, and their application to deadlock control. As a reference, this work attempts to provide a comprehensive and updated research survey on siphons, elementary siphons, and their applications to the deadlock resolution in Petri nets.

A Structure Causality Relation for Liveness Characterisation in Petri Nets

Journal of Universal Computer Science - J.UCS, 2005

Characterising liveness using a structure based approach is a key issue in theory of Petri nets. In this paper, we introduce a structure causality relation from which a topological characterisation of liveness in Petri nets is defined. This characterisation relies on a controllability property of siphons and allows to determine the borders of the largest abstract class of Petri nets for which equivalence between liveness and deadlock-freeness holds. Hence, interesting subclasses of P/T systems, for which membership can be easily determined, are presented. Moreover, this paper resumes, from a new point of view, similar results related to this issue and, provides a unified interpretation of the causes of the non-equivalence between liveness and deadlock-freeness. Place/Transition (P/T) nets (Reisig 91) are well-known models for the representation and analysis of concurrent systems. The use of structural methods for the behavioural analysis of such systems presents two major advantages...