Use Of Petri Nets Research Articles

Modelling intelligent agents for autonomic computing in the PNagent framework

Petri nets have proven to be a valuable tool for modelling concurrent systems. As such, they should be suitable for modelling agent and multi-agent systems, as these are inherently concurrent. Nevertheless, there are not many systems that allow the modelling of the whole multi-agent system in Petri nets. The use of Petri nets is usually limited to subproblems such as the verification of interaction protocols. This paper describes the main concepts of PNagent – a tool for modelling Believe-Desire-Intention (BDI) agents using the formalism of Object-Oriented Petri Nets (OOPN). PNagent allows for developing, testing and running software agents in a consistent graphical environment. The framework is suitable for prototyping and experiments with both multi-agent applications and the particular agent architecture itself. At the same time, thanks to the formal nature of its underlying paradigm, it provides the means to verify an agent's properties. Thanks to its consistent environment and the high-level nature of the used formalism, the framework is also suitable for incorporating the ideas of autonomic computing.

Validation by Petri net of a new approach for the one machine problem with temporal functions of polynomial type

Abstract This paper deals with the use of Petri nets in a specific class of scheduling issues. Indeed, in a specific type of one machine problems, the job processing time is not any more constant but depend on time. When the temporal functions representing the evolution of the processing time of the tasks are polynomial functions, the problems are difficult to resolve in certain cases. We propose an algorithm which is validated by a Petri net model to give a feasible solution.

PENTRAL: Pattern Based Logic Language

INTRODUCTION The increase of Motor vehicles in recent years has been phenomenal and importance of road traffic in supporting the social and economic activities every increase; as the result, road congestion, accident, air pollution is becoming serious year after year. In urban area, it has been difficult to implement a drastic plan like a new road construction as a resolution for traffic congestion (Asgekar, 2003; Wray, Markham, & Mathieu, 2003; Daribari, Medhavi, & Srivastava, 2007; Daribari, Medhavi, & Srivastava, 2008). So we are forced to find out other practicable solutions based on individual conditions of actual road configuration and available technologies. It is beneficial to develop some representation format which could support dynamic graphical representation. The Microscopic graphical representation could contribute to this requisite as a competent tool to explain details of relationships between traffic flows and proposed alternatives both from logical and experimental points of view. Most of previous studies worked on architectural analysis but there is little being done on development of Language development of Workflow system with special emphasis on urban Traffic systems (Darbari & Bhaskar, 2008; Dvorak & Novak, 2003; Georgakopoulos, Homick, & Sheth, 1995; Panagos & Rabinovich, 1996; Knybel, 2005). We have shown the traffic flow by the help of Petri-net graphs Wang, 1998; Kepuska, Grubuz, rodriguez, Fiore, Carsten, converse, & Metcalf, 2008; Zhang, Lin, & Hsieh, 2008). The use of Petri-nets have been criticized for the use in modeling complex business processes, specially when dealing with multilayer graphical representation but Petri-net Transportation Language (PENTRAL) provides an extension to Petri-net theory providing a set of techniques to describe complex traffic management process. It could offer a technique with perfect verification capabilities and comprehensible models. The purpose of this paper is to show how Petri-net language can provide pattern interactions. PENTRAL will provide an easy representation of objects like route section and link in which represent a part of the layered tree structure. The control flow aspects of urban Traffic system will define the alphabet of a labeled Petri-net as the set of activities of the process, the Petri-net generate a language over the task of the processes: LITERATURE REVIEW Urban TNs (Transport Networks) exhibit high degree of concurrency and are characterized by resource sharing and conflicts. Hence, appropriate models of these systems have to take into account such distinctive features, in order to result in efficient traffic management strategies. In particular, urban TNs can be viewed as event driven and asynchronous systems. Their dynamics depends on the complex interactions of the timing of various discrete events, such as arrivals or departures of vehicles at intersections and beginning or completion of the various phases in the signal timing plans of the traffic lights controlling junctions. Thanks to the well known ability of Petri Nets (PNs) to capture concurrency and asynchrony, PN based models may be suitably derived for urban traffic systems. More precisely, PNs can be employed both for describing traffic signals controlling urban signalized areas, as well as for modeling concurrent activities that are typical of TNs. Tensen (1992) present a traffic model in a timed PN framework, where tokens are vehicles and places are parts of lanes and intersections. Since in PNs tokens cannot distinguish among different vehicles and their associated routes, colours are introduced in (Murata, 1989), where a different number (colour) is assigned to each vehicle entering the system. The model is realized by defining appropriate subnets modeling links and intersections: PATTERNS IN PETRI-NETS REPRESENTATION Traditionally most techniques used for the analysis of Business process originate from operation research. …

Microcontroller-Based Process Monitoring Using Petri-Nets

This paper considers the development of a Petri-net-based modelling tool as a mechanism for process and system monitoring. The use of Petri-nets, which has previously been largely based in the areas of systems modelling and simulation, is shown here to have great potential for deployment as a process monitoring and management application. Interfacing with real-world processes has been achieved in part by introducing a specific set of extensions to the original Petri-net concept. This work has resulted in the engineering of a tool that can be embedded within the process using a microcontroller platform. The potential for such systems to provide low cost, yet powerful process management tools, is becoming increasingly evident, particularly given the ever-improving capabilities of microcontrollers.

Modeling and Simulation of Projects with Petri Nets

Traditional project management tools and other revised tools are limited in representation of the problem and in dealing situation dynamically. This paper details the use of Petri nets as a graphical and mathematical modeling and simulation tool in project management. In this context, the benefits of Petri nets are indicated. A Petri net aided software, a PETRI-PM is developed to model, simulate and analyze the project. Extensions to make Petri nets suitable for project management applications are proposed. The use of a PPC-matrix for token movements is proposed. The paper also discusses the implications of the model and the analysis it supports. The usefulness of the software is exemplified with a case study.

Applications of Petri nets in production scheduling: a review

The production scheduling problem allocates limited resources to tasks over time and determines the sequence of operations so that the constraints of the system are met and the performance criteria are optimized. One approach to this problem is the use of Petri nets in conjunction with other methods. In this paper, we give a comprehensive overview for production scheduling research that combines PNs with other methods, discuss both theoretical developments and practical experiences, and identify research trends. More than 20 major production and operations management journals published in years 1989–2005 has been reviewed. Existing approaches are classified into four groups, and additionally a historical progression in this field was emphasized. Finally, recommendations for future research are suggested in this paper.

Deterministic Petri Net Languages as Business Process Specification Language

Today, a wide variety of techniques have been proposed to model the process aspects of business processes. The problem, however, is that many of these are focused on providing a clear graphical representation of the models and give almost no support for complex verification procedures. Alternatively, the use of Petri Nets as a business process modeling language has been repeatedly proposed. In complex business processes the use of Petri Nets has been criticized and the technique is believed to be unable to capture such processes in all aspects. Therefore, in this paper, we introduce the application of Petri Net language theory for business process specification. Petri Net languages are an extension to the Petri Net theory, and they provide a set of techniques to describe complex business processes more efficiently. More specifically, we advocate the application of deterministic Petri Net languages to model the control flow aspects of business processes. The balance between modeling power and analysis possibilities makes deterministic Petri Nets a highly efficient technique, used in a wide range of domains. The proof of their usability, as business process specification language, is given by providing suitable solutions to model the basic and more complex business process patterns [4]. Additionally, some points of particular interest are concisely discussed.

MORM—A Petri Net Based Model for Assessing OH&S Risks in Industrial Processes: Modeling Qualitative Aspects

Because of the increase in workplace automation and the diversification of industrial processes, workplaces have become more and more complex. The classical approaches used to address workplace hazard concerns, such as checklists or sequence models, are, therefore, of limited use in such complex systems. Moreover, because of the multifaceted nature of workplaces, the use of single-oriented methods, such as AEA (man oriented), FMEA (system oriented), or HAZOP (process oriented), is not satisfactory. The use of a dynamic modeling approach in order to allow multiple-oriented analyses may constitute an alternative to overcome this limitation. The qualitative modeling aspects of the MORM (man-machine occupational risk modeling) model are discussed in this article. The model, realized on an object-oriented Petri net tool (CO-OPN), has been developed to simulate and analyze industrial processes in an OH&S perspective. The industrial process is modeled as a set of interconnected subnets (state spaces), which describe its constitutive machines. Process-related factors are introduced, in an explicit way, through machine interconnections and flow properties. While man-machine interactions are modeled as triggering events for the state spaces of the machines, the CREAM cognitive behavior model is used in order to establish the relevant triggering events. In the CO-OPN formalism, the model is expressed as a set of interconnected CO-OPN objects defined over data types expressing the measure attached to the flow of entities transiting through the machines. Constraints on the measures assigned to these entities are used to determine the state changes in each machine. Interconnecting machines implies the composition of such flow and consequently the interconnection of the measure constraints. This is reflected by the construction of constraint enrichment hierarchies, which can be used for simulation and analysis optimization in a clear mathematical framework. The use of Petri nets to perform multiple-oriented analysis opens perspectives in the field of industrial risk management. It may significantly reduce the duration of the assessment process. But, most of all, it opens perspectives in the field of risk comparisons and integrated risk management. Moreover, because of the generic nature of the model and tool used, the same concepts and patterns may be used to model a wide range of systems and application fields.

Modeling Traffic Signal Control Using Petri Nets

This paper focuses on the use of Petri nets (PN) to model the control of signalized intersections. The application of PN to an eight-phase traffic signal controller is illustrated. Structural analysis of the control PN model is performed to demonstrate how the model enforces the traffic operation safety rules. This is followed by a discussion of why this modeling tool has future value as the use of more advanced control strategies continue to expand.

Simulation and Optimization of Logistic and Production Systems Using Discrete and Continuous Petri Nets

The use of Petri nets as a tool for optimizing logistic systems of industrial supply by simulation is analyzed in this article. The application of these tools presents two basic advantages: (1) their graphic/mathematical interpretation makes them particularly useful to be applied in simulation/analysis (optimization) applications, and (2) they can be considered from a discrete/continuous point of view, as a paradigm for modeling and analyzing discrete systems or as a continuous approximation to the real discrete model. These properties are very interesting in a global simulation analysis of logistic systems because their management is usually limited by their high complexity and large dimension. Petri nets are applied to the modeling and analysis of discrete logistic systems in the classical way, using the relatively recent continuization and fluidification techniques of discrete systems for their continuous approximation. This new methodology provides results with less computational effort.

Specific proposals for the use of petri nets in a concurrent programming course

Concurrency is a difficult subject to teach and learn. This paper presents a set of recipes for the use of Petri nets as a teaching aid of some fundamental concurrency concepts, in the context of an introductory concurrent programming course. Classroom experience clearly demonstrates this usage of Petri nets improves students understanding of concurrency concepts.

Two-dimensional occluded object matching using petri nets

This article discusses the use of Petri nets to model the process of object matching between an image and a model under different two-dimensional geometric transformations. This transformation finds its applications in sensor-based robot control, flexible manufacturing systems, industrial inspection, and so on. Its topological structure relation, called point-line relation structure (PLRS), presents a Petri net-based description approach for object structure. It has been shown how Petri nets can be used to model the matching process, and an optimal or near optimal matching can be obtained by tracking the reachability graph of the net. The experiment result shows that objects can be successfully identified and located under two-dimensional transformation such as translations, rotations, scale changes, and distortions due to partial object occlusion. © 2002 Wiley Periodicals, Inc.

Tokenplan: A Planner for Both Satisfaction and Optimization Problem

Tokenplan is a planner based on the use of Petri nets. Its main feature is the flexibility it offers in the way it builds the planning graph. The Fifth International Conference on Artificial Intelligence Planning and Scheduling planning competition validated its behavior with a graphplan-like behavior. The next step is to demonstrate the benefits we expect from our planner in planning problems involving optimization and uncertainty handling.

The Petri Net Baukasten: 2nd Installment

Petri nets are a subject of interest to researchers since more than 30 years. They became popular since they allow the graphic representation of computational structures and have a formal underpinning that allows formal proofs of properties. Their use in engineering, however is limited to a rather small number of applications. Many of the graphic notations used in practice are very similar to the graphic representation of Petri nets but do not make use of the rich body of theory that exists for Petri nets. This is repeatedly attributed to the fact that Petri nets and the associated theory are hard to understand and real life problems modelled with Petri nets tend to require special brands of Petri nets which in turn led to a great variety of different net types. Finding the right Petri net types from the portfolio of existing types, finding corresponding techniques and tools, selecting them and applying them successfully to applications poses a problem and prevents their wide spread use. In order to improve this situation, a Petri Net Baukasten has been developed by the DFG-Forschergruppe Petri Net Technology in Berlin. It aims at the development of a support environment for the use of Petri nets in new applications including theoretical and tool aspects. This paper presents the 2nd Installment of the Petri Net Baukasten, which extends the first installment of the Petri Net Baukasten, documented as Initial Realization in 1999, by providing interfaces, services, and data for specific user groups such as application developers, tool developers and Petri net experts. The user interface offers an intuitive presentation of Petri net concepts and notions. The Petri Net Baukasten supports different user groups in their specific work with Petri nets by user specific assistence services. These services allow the users to find the right Petri net types in a variety of existing types and support their selection and use. Information is kept in an associated database. Furthermore the assistence services maintain this database in order to keep track of recent developments in theory, tools and application areas.

Reliability modelling of repairable systems using Petri nets and fuzzy Lambda–Tau methodology

Abstract A methodology is developed which uses Petri nets instead of the fault tree methodology and solves for reliability indices utilising fuzzy Lambda–Tau method. Fuzzy set theory is used for representing the failure rate and repair time instead of the classical (crisp) set theory because fuzzy numbers allow expert opinions, linguistic variables, operating conditions, uncertainty and imprecision in reliability information to be incorporated into the system model. Petri nets are used because unlike the fault tree methodology, the use of Petri nets allows efficient simultaneous generation of minimal cut and path sets.

Reliability Analysis of Systems using Petrinets

This paper gives an overview of the use of petrinets for the reliability analysis of safety systems. Fault tree technique had been widely employed in the reliability analysis of safety systems as a part of Level 1 Probabilistic Safety Assessment conducted for Nuclear Power Plants. This study presents the use of petrinets in failure analysis. It is demonstrated that petrinets are more efficient than fault tree. Another arena, where petrinets were successfully employed, is in the evaluation of redundant systems where time is also one of the parameters. Analyses are presented with the help of appropriate case studies.

Petri Nets for Project Management and Resource Levelling

Conventional management tools are restricted in their application. This paper details the use of Petri nets (PNs) in project management. In this context, the benefits of PNs are indicated. Extensions to PNs are proposed to suit this area of application. The use of a P-matrix for token movements is proposed. A resource levelling algorithm is described and applied to a case study.

Development of a shipyard simulator based on Petri nets

There are many restrictions on production in the factory. The most efficient production schedule should be planned taking these restrictions into account. Professional skill is necessary to plan the best schedule. A schedule planner has to deal with so much information during production planning that it is difficult to plan the best production schedule with a consideration of so many restrictions. In this study we introduced the use of Petri nets to support such production planning with a computer. Petri nets have been widely used to simulate production because of their capability of modeling concurrency, synchronization, and sequencing in discrete-event systems. This paper reports on implementing a simulation system for the shipyard. We had already implemented a production planning support system for a shipyard that is a part of the computer integrated manufacturing (CIM) system in shipbuilding. Based on this system, we implemented a shipyard simulator that can simulate the production activity in the shipyard. We therefore have defined a shipyard model. The production conditions can be changed, and the efficiency of a schedule can be evaluated. This paper discusses the effectiveness of using a factory simulator.

A Petri net model for probabilistic logic

In this article we investigate the use of Petri nets for the representation of possible worlds in probabilistic logic. We propose a method to generate possible worlds based upon the reachability tree of the Petri net model. The number of columns in the matrix of possible worlds grows exponentially with the problem size. Nilsson [Proceedings of 1976 National Computer Conference and Readings in Artificial Intelligence, Morgan Kaufmann, Los Altos, CA, 1981, pp. 192-199] suggested a method to generate only those columns of the possible world matrix that are likely to be important for the solution. We provide Petri net models for the method suggested by Nilsson and show that they lead to intuitive and simple computational methods.

Animation modeling with petri nets

This paper introduces the use of Petri Nets as a modeling and analysis tool for animation environments. Firstly, the original formulation for Petri Nets is applied in two animation situations, one modeled as a state machine and another exploring interdependent transitions. Increasing the complexity level, some modeling extensions are discussed and more sophisticated animation examples are studied.