Petri Net Structure Research Articles

ペトリネット構造と有向グラフの関係に関する考察

ペトリネット構造と有向グラフの関係に関する考察

A Design Method of the Conflict-Free Petri Net Models for the Manufacturing Systems Control

A certain class of Petri nets interpreted for control, shortly CTRL - Petri nets, are introduced and defined in the paper. Three basic elementary CTRL - Petri net structures are described reflecting three main control situations with respect to conflict decision problem in the flexible manufacturing systems (FMS). Two main sources of the conflicts in the FMS are analyzed and specified. Then a method for removal of the conflicts in the FMS modelling CTRL - Petri net is presented. The method is illustrated on a practical example.

Petri Nets for Simulation and Modeling of Construction Systems

Simulation and modeling of construction systems have been actively researched over the past 20 years. This paper demonstrates how Petri nets, a powerful modeling tool previously used for modeling computer networks and automated manufacturing systems, can be used effectively for modeling construction systems. This paper describes the Petri net approach to modeling and shows how models of construction systems can be developed. Several common Petri net structures and features useful in construction system modeling are described. Time and color Petri nets and their application in modeling specific characteristics of construction systems are discussed. Two illustrative examples are presented and the advantages and disadvantages of Petri nets as tools for the modeling and simulation of construction operations are detailed.

Validation and Verification of Decision Making Rules

A methodology for the validation and verification (V&V) of decision making rules is proposed. The methodology addresses the general problem of detecting problematic cases in a set of rules. The rules are expressed as statements in formal logic. The definition of decision rules in formal logic makes the problem general in terms of application domains, and also provides an analytical base for defining errors. The approach is based on viewing a rule base as an organization of information that flows from one process (rule) to another. Since Petri Nets provide a powerful modeling and analysis tool for information flow structures, the methodology transforms a set of decision rules into an equivalent Petri Net representation. The static and dynamic properties of the graph are shown to reveal patterns of Petri Net structures that correspond to the problematic cases. The tools and techniques presented in this paper are based on theory and are supported by software tools.

Synchronization models for multimedia presentation with user participation

This paper addresses the key issue of providingflexible multimedia presentation with user participation and suggests synchronization models that can specify the user participation during the presentation. We study models like the Petrinet-based hypertext model and the object composition Petri nets (OCPN). We suggest adynamic timed Petri nets structure that can model pre-emptions and modifications to the temporal characteristics of the net. This structure can be adopted by the OCPN to facilitate modeling of multimedia synchronization characteristics with dynamic user participation. We show that the suggested enhancements for the dynamic timed Petri nets satisfy all the properties of the Petri net theory. We use the suggested enhancements to model typical scenarios in a multimedia presentation with user inputs.

Un outil de modélisation pour les systèmes physiques complexes

An examination of a particular Petri Net structure has been carried out. The characteristics of this Petri Network are in good agreement with classical tools used in simulation. A few notions like attractors, attractor bassin or disturbance of a system are introduced here for Petri Nets. It appears that the Petri Net can be a good tool for physicists and automaticians

ペトリネットの構造解析と計数プレースの付加法

ペトリネットの構造解析と計数プレースの付加法

Petri net based node structures for distributed problem solving in FMS control

A Distributed Problem Solving (DPS) architecture (SCOPE) for the control of Flexible Manufacturing Systems is presented. The controller kernel is intended to be easily adapted for different manufacturing systems, and we propose this as a basis for the standardization of control architectures from the point of view of control system designers. Our concern is the dynamic (rapid) generation of flexible solutions to a control problem with several discrete decision variables. Each node consists of the object class (or classes) that it deals with, its local model (which describes the dynamics of the node), and a set of problem solving agents (knowledge sources), that could be invoked by this node. An object class is represented by a Petri net with an object orientated interpretation (PNO), and acts as a structured local database or a local hypothesis register. The local model indicates the conditions under which this problem solving node could invoke any of its agents, and also when a node demands the services of another node, this demand is formulated through the local model. A node calling for the treatment of its local hypothesis modification does not know the node which will respond. Inside a node its KSs are also disconnected (uncoupled), and react in an opportunistic manner. This control structure permits parallel activation of KSs. The protocols for activation, running, termination (normal and abnormal) and resumption of the different KS types are specified with generic Petri net structures. A detailed description of the problem solving mechanism in SCOPE is given for the activities involving the Batching node.

Partial order behaviour and structure of Petri nets

Abstract This paper argues that partial order semantics can be used profitably in the proofs of some nontrivial results in Petri net theory. We show that most of Commoner's and Hack's structure theory of free choice nets can be phrased and proved in terms of partial order behaviour. The new proofs are considerably shorter (and, arguably, more lucid) than the old ones; they also generalise the results from (safe) free choice nets to (bounded) extended free choice nets.

A method to determine the number of firings by classification of petri net structure and addition of counter place.

A method to determine the number of firings by classification of petri net structure and addition of counter place.

Petri net as a modeling tool

Over the last decade, Petri nets have emerged as a most suitable, powerful and widely acceptable modeling tool for representing and studying the asynchronous concurrent hardware (or software) systems/processes. Petri nets can be viewed as formal automata or as an automation which can generate the formal languages or a model to analyse and synthesize various kinds of systems. The structure of Petri nets, their markings, extensions and subclasses are briefly discussed. Several examples of Petri net models of computer hardware and software are presented. Various applications of reachability concepts are also given.

Petri net approach to the analysis of a structured program

The analysis problem of complexity and execution time of a structured program has been tackled using the concept of Petri net (PN). This type of representation is useful due to its graphical and precise nature of representation scheme and also the established relationship between certain net structure and dynamic behaviour of PN can be used as a tool for analysing the behavior of the system. A PN representation of various nested blocks of the structured program is given. The firing characteristic of the transitions in a PN has been used to give an interpretation to each of the blocks and it is shown how each of the blocks can be simplified with a view to calculating the total execution time of a program. It is simple as it gives a straightforward procedure for analysing the program.