Showing papers on "Petri net published in 2007"

Coloured Petri Nets and CPN Tools for modelling and validation of concurrent systems

Abstract: Coloured Petri Nets (CPNs) is a language for the modelling and validation of systems in which concurrency, communication, and synchronisation play a major role. Coloured Petri Nets is a discrete-event modelling language combining Petri nets with the functional programming language Standard ML. Petri nets provide the foundation of the graphical notation and the basic primitives for modelling concurrency, communication, and synchronisation. Standard ML provides the primitives for the definition of data types, describing data manipulation, and for creating compact and parameterisable models. A CPN model of a system is an executable model representing the states of the system and the events (transitions) that can cause the system to change state. The CPN language makes it possible to organise a model as a set of modules, and it includes a time concept for representing the time taken to execute events in the modelled system. CPN Tools is an industrial-strength computer tool for constructing and analysing CPN models. Using CPN Tools, it is possible to investigate the behaviour of the modelled system using simulation, to verify properties by means of state space methods and model checking, and to conduct simulation-based performance analysis. User interaction with CPN Tools is based on direct manipulation of the graphical representation of the CPN model using interaction techniques, such as tool palettes and marking menus. A license for CPN Tools can be obtained free of charge, also for commercial use.

Petri net modelling of biological networks

Abstract: Mathematical modelling is increasingly used to get insights into the functioning of complex biological networks. In this context, Petri nets (PNs) have recently emerged as a promising tool among the various methods employed for the modelling and analysis of molecular networks. PNs come with a series of extensions, which allow different abstraction levels, from purely qualitative to more complex quantitative models. Noteworthily, each of these models preserves the underlying graph, which depicts the interactions between the biological components. This article intends to present the basics of the approach and to foster the potential role PNs could play in the development of the computational systems biology.

A Time Petri Net Extended with Price Information

Abstract: Performance and cost analysis are the two main purposes of business process modeling, where the Petri net extended with time information is an effective tool for performance analysis, but not for cost analysis. This paper proposes a time Petri net extended with price information—Price Time Petri Net. Firstly, this paper associates a price with a time transition, and gives the semantics for price time Petri net in terms of priced timed transition systems. Then it defines a priced state class as an extension of state class, and discusses the soundness and completeness for this extension. An algorithm is given to prove that the minimum-cost reachability problem for bounded price time Petri net is decidable. Finally, this paper gives an example and draws a conclusion that incorporating price information in time Petri net and applying price time Petri net to business process management

An Iterative Synthesis Approach to Petri Net-Based Deadlock Prevention Policy for Flexible Manufacturing Systems

Abstract: This paper proposes an iterative synthesis approach to Petri net (PN)-based deadlock prevention policy for flexible manufacturing systems (FMS). Given the PN model (PNM) of an FMS prone to deadlock, the goal is to synthesize a live controlled PNM. Its use for FMS control guarantees its deadlock-free operation and high performance in terms of resource utilization and system throughput. The proposed method is an iterative approach. At each iteration, a first-met bad marking is singled out from the reachability graph of a given PNM. The objective is to prevent this marking from being reached via a place invariant of the PN. A well-established invariant-based control method is used to derive a control place. This process is carried out until the net model becomes live. The proposed method is generally applicable, easy to use, effective, and straightforward although its off-line computation is of exponential complexity. Two FMS are used to show its effectiveness and applicability

A Petri net approach to the study of persistence in chemical reaction networks

Abstract: Persistence is the property, for differential equations in R(n), that solutions starting in the positive orthant do not approach the boundary of the orthant. For chemical reactions and population models, this translates into the non-extinction property: provided that every species is present at the start of the reaction, no species will tend to be eliminated in the course of the reaction. This paper provides checkable conditions for persistence of chemical species in reaction networks, using concepts and tools from Petri net theory, and verifies these conditions on various systems which arise in the modeling of cell signaling pathways.

Process mining based on regions of languages

Abstract: In this paper we give an overview, how to apply region based methodsfor the synthesis of Petri nets from languages to process mining The research domain of process mining aims at constructing a process modelfrom an event log, such that the process model can reproduce the log, and doesnot allow for much more behaviour than shown in the log We here considerPetri nets to represent process models Event logs can be interpreted as finite languagesRegion based synthesis methods can be used to construct a Petri net froma language generating the minimal net behaviour including the given languageTherefore, it seems natural to apply such methods in the process mining domainThere are several different region based methods in literature yielding differentPetri nets We adapt these methods to the process mining domain and comparethem concerning efficiency and usefulness of the resulting Petri net

A feature-complete Petri net semantics for WS-BPEL 2.0

Abstract: We present an extension of a Petri net semantics for the Web Service Business Execution Language (WS-BPEL). This extension covers the novel activities and constructs introduced by the recent WS-BPEL 2.0 specification. Furthermore, we simplify several aspects of the Petri net semantics to allow for more compact models suited for computer-aided verification.

Design of Liveness-Enforcing Supervisors for Flexible Manufacturing Systems Using Petri Nets

Abstract: This correspondence develops a methodology to synthesize supervisors for a special class of Petri nets that can well model many flexible manufacturing systems. In our previous work, siphons in a Petri net are divided into elementary and dependent ones on the condition that all emptiable minimal siphons are computed. In this research, a mixed integer programming (MlP)-based deadlock detection technique is used to find some, in general not all, minimal siphons in a plant model without complete siphon enumeration. For each siphon found, depending on its noncontrollability, a monitor is added such that it is invariant-controlled. Our siphon control method guarantees that no emptiable control-induced siphon is generated due to the addition of the monitors. The siphon control process proceeds iteratively until there is no unmarked siphon in the supervisor of a plant model. Compared with the existing approaches, the novel deadlock prevention policy can usually lead to a structurally simple liveness-enforcing supervisor by adding only a small number of monitors and arcs. More importantly, complete siphon enumeration is avoided. A practical flexible manufacturing system (FMS) example is utilized to illustrate the proposed methods.

ProM 4.0: comprehensive support for real process analysis

Abstract: This tool paper describes the functionality of ProM. Version 4.0 of ProM has been released at the end of 2006 and this version reflects recent achievements in process mining. Process mining techniques attempt to extract non-trivial and useful information from so-called "event logs". One element of process mining is control-flow discovery, i.e., automatically constructing a process model (e.g., a Petri net) describing the causal dependencies between activities. Control-flow discovery is an interesting and practically relevant challenge for Petri-net researchers and ProM provides an excellent platform for this. For example, the theory of regions, genetic algorithms, free-choice-net properties, etc. can be exploited to derive Petri nets based on example behavior. However, as we will show in this paper, the functionality of ProM 4.0 is not limited to control-flow discovery. ProM 4.0 also allows for the discovery of other perspectives (e.g., data and resources) and supports related techniques such as conformance checking, model extension, model transformation, verification, etc. This makes ProM a versatile tool for process analysis which is not restricted to model analysis but also includes log-based analysis.

Online Fault Diagnosis of Discrete Event Systems. A Petri Net-Based Approach

Abstract: This paper is concerned with an online model-based fault diagnosis of discrete event systems. The model of the system is built using the interpreted Petri nets (IPN) formalism. The model includes the normal system states as well as all possible faulty states. Moreover, it assumes the general case when events and states are partially observed. One of the contributions of this work is a bottom-up modeling methodology. It describes the behavior of system elements using the required states variables and assigning a range to each state variable. Then, each state variable is represented by an IPN model, herein named module. Afterwards, using two composition operators over all the modules, a monolithic model for the whole system is derived. It is a very general modeling methodology that avoids tuning phases and the state combinatory found in finite state automata (FSA) approaches. Another contribution is a definition of diagnosability for IPN models built with the above methodology and a structural characterization of this property; polynomial algorithms for checking diagnosability of IPN are proposed, avoiding the reachability analysis of other approaches. The last contribution is a scheme for online diagnosis; it is based on the IPN model of the system and an efficient algorithm to detect and locate the faulty state. Note to Practitioners-The results proposed in this paper allow: 1) building discrete event system models in which faults may arise; 2) testing the diagnosability of the model; and 3) implementing an online diagnoser. The modeling methodology helps to conceive in a natural way the model from the description of the system's components leading to modules that are easily interconnected. The diagnosability test is stated as a linear programming problem which can be straightforward programmed. Finally, the algorithm for online diagnosis leads to an efficient procedure that monitors the system's outputs and handles the normal behavior model. This provides an opportune detection and location of faults occurring within the system

Qualitatively modelling and analysing genetic regulatory networks: a Petri net approach

Abstract: Motivation: New developments in post-genomic technology now provide researchers with the data necessary to study regulatory processes in a holistic fashion at multiple levels of biological organization. One of the major challenges for the biologist is to integrate and interpret these vast data resources to gain a greater understanding of the structure and function of the molecular processes that mediate adaptive and cell cycle driven changes in gene expression. In order to achieve this biologists require new tools and techniques to allow pathway related data to be modelled and analysed as network structures, providing valuable insights which can then be validated and investigated in the laboratory. Results: We propose a new technique for constructing and analysing qualitative models of genetic regulatory networks based on the Petri net formalism. We take as our starting point the Boolean network approach of treating genes as binary switches and develop a new Petri net model which uses logic minimization to automate the construction of compact qualitative models. Our approach addresses the shortcomings of Boolean networks by providing access to the wide range of existing Petri net analysis techniques and by using non--determinism to cope with incomplete and inconsistent data. The ideas we present are illustrated by a case study in which the genetic regulatory network controlling sporulation in the bacterium Bacillus subtilis is modelled and analysed. Availability: The Petri net model construction tool and the data files for the B. subtilis sporulation case study are available at http://bioinf.ncl.ac.uk/gnapn Contact: L.J.Steggles@ncl.ac.uk

Distributed Diagnosis of Place-Bordered Petri Nets

Abstract: This paper studies online fault detection and isolation of modular dynamic systems modeled as sets of place-bordered Petri nets. The common places among the set of Petri nets modeling a system capture coupling of various system components. The transitions are labeled by events, some of which are unobservable (i.e., not directly recorded by the sensors attached to the system). The events whose occurrence must be diagnosed have unobservable transition labels. These events model faults or other significant changes in the system state. The existing theory of diagnosis of discrete-event systems is extended in the context of the above model. The modular structure of the system is exploited by a distributed algorithm for fault diagnosis. A Petri net diagnoser is associated with every Petri net and the diagnosers communicate in real time during the diagnostic process when the token count of common places changes. A merge function is defined to combine the individual diagnoser states and recover the complete diagnoser state that would be obtained under a monolithic approach. Strategies that reduce the communication overhead are presented. The software implementation of the distributed algorithm is discussed. Note to Practitioners-In the last decade, monitoring, fault detection, and diagnosis methodologies based on the use of discrete-event models have been successfully used in a variety of technological systems ranging from document processing systems to intelligent transportation systems. This paper was motivated by the problem of fault diagnosis for modular (distributed) dynamic discrete-event systems (DES). As a DES modeling formalism, Petri nets offer potential advantages in terms of the distributed representation of the system and the ability to represent coupling of the system components. The systems studied in this paper are sets of modules coupled with each other through various system components and modeled using Petri nets. We present a distributed fault diagnosis algorithm which allows each module in the distributed system to diagnose its faults independently unless completion of a task requires the use of coupled components. In the case of coupling, modules communicate with each other to accurately diagnose the fault. The distributed fault diagnosis algorithm recovers the monolithic diagnosis information at the cost of communication and growing communication overhead. To mitigate that problem, we present an improved version of the algorithm that significantly reduces the communication overhead. Finally, we introduce the software toolbox (written in Matlab and integrated with AT&T Graphviz) and we present a case study of an example of a heating, ventilation, and air-conditioning system where we use the software tool for modeling and analyzing the system

Handbook of Dynamic System Modeling

Abstract: INTRODUCTION The Languages of Dynamic System Modeling by Paul A. Fishwick Introduction Dynamic System Modeling Examples Taxonomic Approaches Language Syntax Semantics Pragmatics Summary The Dynamics of the Computational Modeling of Analogy-Making by Robert M. French Introduction Analogy-Making as Sameness Analogy-Making as a Means of "Bootstrapping" Cognition The Necessity of Malleable Representations The Dynamics of Representation-Building in Analogy-Making Context-Dependent Computational Temperature Interaction between Top-Down and Bottom-Up Processes: An Example Computational Models Implementing This Bottom-Up/Top-Down Interaction Architectural Principles How This Type of Program Works: The Details How Tabletop Finds a Reasonable Solution The Issue of Scaling Up The Potential Long-Term Impact of the Mechanisms Presented Conclusions Impact of the Semantic Web on Modeling and Simulation by John A. Miller, Congzhou He, and Julia I. Couto Introduction Semantic Web: Relevant Issues Conceptual Basis for Discrete-Event Simulation Types of Mathematical Models Adding Semantics to Simulation Models Overview of DeSO Overview of DeMO Summary Systems Engineering by Andrew P. Sage Introduction Systems Engineering The Importance of Technical Direction and Systems Management Other Parts of the Story Summary Basic Elements of Mathematical Modeling by Clive L. Dym Principles of Mathematical Modeling Dimensional Consistency and Dimensional Analysis Abstraction and Scale Conservation and Balance Principles The Role of Linearity Conclusions DEVS Formalism for Modeling of Discrete-Event Systems by Tag Gon Kim Introduction System-Theoretic DES Modeling DEVS Formalism for DES Modeling DES Analysis with DEVS Model Simulation of DEVS Model Conclusion MODELING METHODOLOGIES Domain-Specific Modeling by Jeff Gray, Juha-Pekka Tolvanen, Steven Kelly, Anirudda Gokhale, Sandeep Neema, and Jonathan Sprinkle Introduction Essential Components of a Domain-Specific Modeling Environment Case Studies in DSM Overview of Supporting Tools Conclusion Agent-Oriented Modeling in Simulation: Agents for Modeling and Modeling for Agents by Adelinde M. Uhrmacher and Mathias Rohl Introduction Agents for Modeling in Simulation Modeling and Simulation for Agents Conclusion Distributed Modeling by Simon J.E. Taylor Introduction Modeling with COTS Simulation Packages Distributed Simulation CSP-Based Distributed Simulation A Standards-Based Approach Case Study Conclusion Model Execution by Kalyan S. Perumalla Introduction Time-Stepped Execution Discrete-Event Execution Summary Discrete-Event Simulation of Continuous Systems by James Nutaro Introduction Simulating a Single Ordinary Differential Equation Simulating Coupled Ordinary Differential Equations DEVS Representation of Discrete-Event Integrators The Heat Equation Conservation Laws Two-Point Integration Schemes Conclusions MULTIOBJECT AND SYSTEM Toward a Multimodel Hierarchy to Support Multiscale Simulation by Mark S. Shephard, E. Seegyoung Seol, and Benjamin FrantzDale Introduction Functional and Information Hierarchies in Multiscale Simulation Constructing a Multimodel: Design of Functional Components to Support Multiscale Simulations Example Multimodel Simulation Procedures Closing Remarks Finite Elements by Marc Hoit and Gary Consolazio Finite Element Theory Membrane Elements Flat Plate and Shell Elements Solid Elements Dynamics Summary Multimodeling by Minho Park, Paul A. Fishwick, and Jinho Lee Introduction Scene Construction Multimodeling Exchange Language (MXL) Dynamic Exchange Language (DXL) A Boiling Water Example Conclusion Hybrid Dynamic Systems: Modeling and Execution by Pieter J. Mosterman Introduction Hybrid Dynamic Systems Hybrid Dynamic System Behaviors An Implementation Advanced Topics in Hybrid Dynamic System Simulation Pathological Behavior Classes Conclusions Theory and Practice for Simulation Interconnection: Interoperability and Composability in Defense Simulation by Ernest H. Page Introduction The Practice of Simulation Interconnection-Simulation Interoperability The Theory of Simulation Interconnection-Simulation Composability Conclusions MODEL TYPES Ordinary Differential Equations by Francisco Esquembre and Wolfgang Christian Introduction Numerical Solution Taylor Methods Runge-Kutta Methods Implementation Adaptive Step Implementation of Adaptive Step Performance and Other Methods State Events The OSP Library Difference Equations as Discrete Dynamical Systems by Hassan Sedaghat Introduction Basic Concepts First-Order Difference Equations Higher Order Difference Equations Process Algebra by J.C.M. Baeten, D.A. van Beek, and J.E. Rooda Introduction Syntax and Informal Semantics of the ? Process Algebra Algebraic Reasoning and Verification Conclusions Temporal Logic by Antony Galton Propositional Logic Introducing Temporal Logic Syntax and Semantics Models of Time Further Extensions to the Formal Language Illustrative Examples Conclusion Further Reading Modeling Dynamic Systems with Cellular Automata by Peter M.A. Sloot and Altons G. Hoekstra Introduction A Bit of History Cellular Automata to Model Dynamical Systems One-Dimensional CAs Lattice Gas Cellular Automata Models of Fluid Dynamics Spatio-Temporal Connectionist Networks by Stefan C. Kremer Introduction Connectionist Networks (CNs) Spatio-Temporal Connectionist Networks Representational Power Learning Applications Conclusion Modeling Causality with Event Relationship Graphs by Lee Schruben Introduction Background and Definitions Enrichments to Event Relations Graphs Relationships to Other Discrete-Event System Modeling Methods Simulation of Event Relationship Graphs Event Relationship Graph Analysis Experimenting with ERGs Petri Nets for Dynamic Event-Driven System Modeling by Jiacun Wang Introduction Petri Net Definition Transition Firing Modeling Power Petri Net Properties Analysis of Petri Nets Colored Petri Nets Timed Petri Nets Concluding Remark Queueing System Models by Christos G. Cassandras Introduction Specification of Queueing System Models Performance of a Queueing System Queueing System Dynamics Little's Law Simple Markovian Queueing Models Markovian Queueing Networks Non-Markovian Queueing Systems Port-Based Modeling of Engineering Systems in Terms of Bond Graphs by Peter Breedveld Introduction Structured Systems: Physical Components and Interaction Bond Graphs Multiport Generalizations Conclusion System Dynamics Modeling of Environmental Systems by Andrew Ford Introductory Examples Comparison of the Flowers and Sales Models Background on Daisy World The Daisy World Model The Daisy World Management Flight Simulator Dynamic Simulation with Energy Systems Language by Clay L. Montague Introduction Reading an Energy Systems Language Diagram Translating a Diagram to Dynamic Equations Calibration of Model Constants Preparation for Simulation Dynamic Output of the Marsh Sector Model A Brief Comparison with Forrester's Systems Dynamics Approach Conclusions Ecological Modeling and Simulation: From Historical Development to Individual-Based Modeling by David R.C. Hill and P. Coquillard Introduction An Old Story? Determinism or Probability? Modeling Techniques The Use of Models in Ecology Models Are Scientific Instruments Levels of Organization and Methodological Choices Individual-Based Models Applications Conclusion Ontology-Based Simulation in Agriculture and Natural Resources by Howard Beck, Rohit Badal, and Yunchul Jung Introduction Ways in Which Ontologies Can Be Applied to Simulation How to Build an Ontology-Based Simulation-Bioprocessing Example Tools for Ontology-Based Simulation Conclusions Modeling Human Interaction in Organizational Systems by Stewart Robinson Introduction Systems and Human Interaction Why Model Human Interaction? Modeling Human Interaction: Research and Practice The KBI Methodology A Case Study: Modeling Human Decision Making at Ford Motor Company Conclusion Military Modeling by Roger Smith Introduction Applications Representation Dynamics Modeling Approach Military Simulation Systems Conclusion Dynamic Modeling in Management Science by Michael Pidd Introduction An Approach to Dynamic Systems Modeling in Management Science Discrete Event Simulation System Dynamics in Management Science Model Validation Chapter Summary Modeling and Analysis of Manufacturing Systems by E. Lefeber and J.E. Rooda Introduction Preliminaries Analytical Models for Steady-State Analysis Discrete-Event Models Effective Process Times Control of Manufacturing Systems: A Framework Standard Fluid Model and Extensions Flow Models Conclusions Sensor Network Component-Based Simulator by Boleslaw K. Szymanski and Gilbert Gang Chen The Need for a New Sensor Network Simulator Component Simulation Toolkit Wireless Sensor Network Simulation Conclusions CASE STUDIES Multidomain Modeling with Modelica by Martin Otter, Hilding Elmqvist, and Sven Erik Mattsson Modelica Overview Modelica Basics Modelica Libraries Symbolic Processing of Modelica Models Outlook Acknowledgments On Simulation of Simulink(R) Models for Model-Based Design by Rohit Shenoy, Brian McKay, and Pieter J. Mosterman Introduction The Case Study Example Designing with Simulation Obtaining Computational Models The Robotic Arm Model Using Computational Models for Control Design Testing with Model-Based Design Conclusions

A formal modeling approach for supply chain event management

Abstract: As supply chains become more dynamic, there is a need for a sense-and-respond capability to react to events in a real-time manner In this paper, we propose Petri nets extended with time and color (to represent case data) as a formalism for managing events We designed seven basic patterns to capture modeling concepts that arise commonly in supply chains These basic patterns may be used by themselves and also combined to create new patterns We also show how to combine the patterns to build a complete Petri net and analyze it using dependency graphs and simulation Dependency graphs can be used to analyze the various events and their causes Simulation was, in addition, used to analyze various performance indicators (eg, fill rates, replenishment times, and lead times) under different strategies We showed it is possible to perform sensitivity analysis to study the effect of changing parameter values on the performance indicators This approach thus makes a very complex problem tractable

Finding Structure in Unstructured Processes: The Case for Process Mining

Abstract: Today there are many process mining techniques that allow for the automatic construction of process models based on event logs. Unlike synthesis techniques (e.g., based on regions), process mining aims at the discovery of models (e.g., Petri nets) from incomplete information (i.e., only example behavior is given). The more mature process mining techniques perform well on structured processes. However, most of the existing techniques fail miserably when confronted with unstructured processes. This paper attempts to "bring structure to the unstructured" by using an integrated combination of abstraction and clustering techniques. The ultimate goal is to present process models that are understandable by analysts and that lead to improved system/process redesigns.

The Input-Output Place-Transition Petri Net Class and Associated Tools

Abstract: Petri nets are a well-known formalism widely used in different application areas. Yet, the lack of adequate tools that can be integrated within engineering development frameworks are one major drawback. This paper identifies and justifies the characteristics of one class of Petri nets targeted for the modelling of automation systems and (networked) embedded systems, named as input-output Petri net (IOPT), and its representation using the Petri net markup language (PNML). The paper also presents a set of associated tools under development. This Petri net class, defined on top of the well-known place-transition Petri nets, is the common link across a set of tools under development, including a graphical editor, a state-space analyser for the verification of properties, conflict resolution through automatic arbiter generation, automatic code generators, simulator, among others. In this sense, the main goal of the proposed Petri net class and associated tools is to support the entire system development flow, from specification to implementation.

An intermediate metamodel with scenarios and resources for generating performance models from UML designs

Abstract: Performance analysis of a software specification in a language such as UML can assist a design team in evaluating performance-sensitive design decisions and in making design trade-offs that involve performance. Annotations to the design based on the UML Profile for Schedulability, Performance and Time provide necessary information such as workload parameters for a performance model, and many different kinds of performance techniques can be applied. The Core Scenario Model (CSM) described here provides a metamodel for an intermediate form which correlates multiple UML diagrams, extracts the behaviour elements with the performance annotations, attaches important resource information that is obtained from the UML, and supports the creation of many different kinds of performance models. Models can be made using queueing networks, layered queues, timed Petri nets, and it is proposed to develop the CSM as an intermediate language for all performance formalisms. This paper defines the CSM and describes how it resolves questions that arise in performance model-building.

Petri nets and Other Models of Concurrency – ICATPN 2007

Abstract: Invited Papers.- Petri Nets, Discrete Physics, and Distributed Quantum Computation.- Autonomous Distributed System and Its Realization by Multi Agent Nets.- Petri Nets Without Tokens.- Toward Specifications for Reconfigurable Component Systems.- Generating Petri Net State Spaces.- Full Papers.- Markov Decision Petri Net and Markov Decision Well-Formed Net Formalisms.- Comparison of the Expressiveness of Arc, Place and Transition Time Petri Nets.- Improving Static Variable Orders Via Invariants.- Independence of Net Transformations and Token Firing in Reconfigurable Place/Transition Systems.- From Many Places to Few: Automatic Abstraction Refinement for Petri Nets.- A Compositional Method for the Synthesis of Asynchronous Communication Mechanisms.- History-Dependent Petri Nets.- Complete Process Semantics for Inhibitor Nets.- Behaviour-Preserving Transition Insertions in Unfolding Prefixes.- Combining Decomposition and Unfolding for STG Synthesis.- Object Nets for Mobility.- Web Service Orchestration with Super-Dual Object Nets.- Synthesis of Elementary Net Systems with Context Arcs and Localities.- Nets with Tokens Which Carry Data.- Operating Guidelines for Finite-State Services.- Theory of Regions for the Synthesis of Inhibitor Nets from Scenarios.- Utilizing Fuzzy Petri Net for Choreography Based Semantic Web Services Discovery.- Formal Models for Multicast Traffic in Network on Chip Architectures with Compositional High-Level Petri Nets.- Name Creation vs. Replication in Petri Net Systems.- Modelling the Datagram Congestion Control Protocol's Connection Management and Synchronization Procedures.- The ComBack Method - Extending Hash Compaction with Backtracking.- Computing Minimal Elements of Upward-Closed Sets for Petri Nets.- Tool Papers.- ProM 4.0: Comprehensive Support for Real Process Analysis.- dmcG: A Distributed Symbolic Model Checker Based on GreatSPN.- Workcraft: A Static Data Flow Structure Editing, Visualisation and Analysis Tool.

Introduction to generalized stochastic Petri nets

Abstract: Generalized Stochastic Petri Nets are a modelling formalism that can be conveniently used for the analysis of complex models of Discrete Event Dynamic Systems and for their performance and reliability evaluation. The automatic construction of the probabilistic models that underly the dynamic behaviours of these nets rely on a set of results that derive from the theory of untimed Petri nets. The paper briefly surveys some results of net theory together with the different approaches used to introduce the concept of time in these models that are useful for the definition of Stochastic Petri Nets and Generalized Stochastic Petri Nets. Details on the solution techniques and on their computational aspects are provided. A brief overview of advanced material is included at the end of the paper to highlight the state of the art in this field and to give pointers to relevant results published in the literature.

A unifying framework for modelling and analysing biochemical pathways using Petri nets

Abstract: We give a description of a Petri net-based framework for modelling and analysing biochemical pathways, which unifies the qualitative, stochastic and continuous paradigms. Each perspective adds its contribution to the understanding of the system, thus the three approaches do not compete, but complement each other. We illustrate our approach by applying it to an extended model of the three stage cascade, which forms the core of the ERK signal transduction pathway. Consequently our focus is on transient behaviour analysis. We demonstrate how qualitative descriptions are abstractions over stochastic or continuous descriptions, and show that the stochastic and continuous models approximate each other. A key contribution of the paper consists in a precise definition of biochemically interpreted stochastic Petri nets. Although our framework is based on Petri nets, it can be applied more widely to other formalisms which are used to model and analyse biochemical networks.

Dynamic analysis of Petri net-based discrete systems

Abstract: Main Notions, Problems and Methods.- Reduced Reachability Graphs.- Decomposition for Analysis.- Analysis by Solving Logical Equations - Calculation of Siphons and Traps.- Verification of Detailed System Descriptions.- Conclusion.

Modeling and Control of Discrete-event Dynamic Systems: with Petri Nets and Other Tools

Abstract: Discrete-event dynamic systems (DEDs) permeate our world, being of great importance in modern manufacturing processes, transportation and various forms of computer and communications networking. Modeling and Control of Discrete-event Dynamic Systems begins with the mathematical basics required for the study of DEDs and moves on to present various tools used in their modeling and control. Among the instruments explained are many forms of Petri net, Grafcet (the sequential function chart), state charts, formal languages and max-plus algebra; all essential for control students to become proficient with DEDs and to make use of them in practical applications. In order to assist tutors with the use of this book in classes it contains fully-worked examples and end-of-chapter exercises with a pdf solutions manual available from springer.com. Realistic industrial examples of varying complexity illustrate the concepts and methods under discussion. Using them, readers will be able to understand DEDs quickly and to master the control methods to analyze and improve the performance of their systems. Final-year undergraduates and graduates embarking on further courses of study in control, manufacturing and process engineering, computer studies or operations research will find Modeling and Control of Discrete-event Dynamic Systems an invaluable companion to learning about the control of this increasingly important class of systems.

Identification and elimination of redundant control places in petri net based liveness enforcing supervisors of FMS

Abstract: In the past two decades, a number of Petri-net-based approaches were proposed for deadlock prevention in flexible manufacturing systems (FMS). An FMS is modeled as a Petri net, and then the controller or the liveness enforcing supervisor (LES) is computed as a Petri net. A live Petri net (LPN) guarantees deadlock-free operations of the modeled FMS. An LES consists of a number of control places (CPs) and their related arcs. To-date most of the attention has been paid to make the underlying Petri net models live without questioning whether or not all of the computed CPs are necessary. It is often the case that the number of CPs determined by these approaches is not minimal. Reducing it in order to reduce the complexity of the controlled system is an important issue that was not tackled before. To address this problem, this paper proposes a redundancy test for an LES of an FMS. The proposed approach takes an LPN model, controlled by n CPs, as input and in the existence of any redundant CPs it produces redundant and necessary CPs. The proposed approach is applicable to any LPN consisting of a Petri net model (PNM), controlled by means of a set of CPs.

Local enforceability in interaction Petri nets

Abstract: In scenarios where a set of independent business partnersengage in complex conversations, global interaction models are a meansto specify the allowed interaction behavior from a global perspective.In these models atomic interactions serve as basic building blocks andbehavioral dependencies are defined between them. Global interactionmodels might not be locally enforceable, i.e. they specify constraints thatcannot be enforced during execution without additional synchronizationinteractions. As this property has only been defined textually so far, thispaper presents a formal definition. For doing so, this paper introducesinteraction Petri nets, a Petri net extension for representing global interactionmodels. Algorithms for deriving the behavioral interface for eachpartner and for enforceability checking are provided.

Diagnosis of DES With Petri Net Models

Abstract: The diagnosis of discrete event systems is strongly related to events estimation. This paper focuses on faulty behaviors modeled with ordinary Petri nets with some "fault" transitions. Partial but unbiased measurement of the places marking variation is used in order to estimate the firing sequences. The main contribution is to decide which sets of places must be observed for the exact estimation of some given firing sequences. Minimal diagnosers are defined that detect and isolate the firing of fault transitions immediately. Causality relationships and directed paths are also investigated to characterize the influence and dependence areas of the fault transitions. Delayed diagnosers are obtained as a consequence. Note to Practitioners-Structural tools are provided for the analysis of models used in the context of fault detection and isolation for discrete event systems. The systems that are concerned are either manufacturing processes, batch processes, digital devices, or communication protocols with single or multiple failures. Methods are proposed to decide, in a systematic way, if the considered failures can be detected and isolated according to the existing sensors. The obtained results can also be used by designers for sensor selection

Definition of an Executable SPEM 2.0

Abstract: One major advantage of executable models is that once constructed, they can be run, checked, validated and improved in short incremental and iterative cycles. In the field of software process modeling, process models have not yet reached the level of precision that would allow their execution. Recently the OMG issued a new revision of its standard for software process modeling, namely SPEM2.0. However, even if executability was defined as a mandatory requirement in the RFP (request for proposal), the adopted specification does not fulfill it. This paper presents a critical analysis on the newly defined standard and addresses its lacks in terms of executability. An approach is proposed in order to extend the standard with a set of concepts and behavioural semantics that would allow SPEM2.0 process models to be checked through a mapping to Petri nets and monitored through a transformation into BPEL.

Petri Nets for Dynamic Event-Driven System Modeling

Abstract: Monmouth University 24.

Generating Petri net state spaces

Abstract: Most specific characteristics of (Place/Transition) Petri nets can be traced back to a few basic features including the monotonicity of the enabling condition, the linearity of the firing rule, and the locality of both. These features enable "Petri net" analysis techniques such as the invariant calculus, the coverability graph technique, approaches based on unfolding, or structural (such as siphon/trap based) analysis. In addition, most verification techniques developed outside the realm of Petri nets can be applied to Petri nets as well. In this paper, we want to demonstrate that the basic features of Petri nets do not only lead to additional analysis techniques, but as well to improved implementations of formalism-independent techniques. As an example, we discuss the explicit generation of a state space. We underline our arguments with some experience from the implementation and use of the Petri net based state space tool LoLA.

Transformation of BPMN Models for Behaviour Analysis

Abstract: In industry, many business processes are modelled and stored in Enterprise Information Systems (EIS). Tools supporting the verification and validation of business processes can help to improve the quality of these business processes. However, existing tools can not directly be applied to models used in industry. In this paper, we present our approach for model verification and validation: translating industrial models to Petri nets and mCRL2, and subsequently applying existing tools on the models derived from the initial industrial models. The following translations are described: BPMN models to Petri nets and Petri nets to mCRL2. It is shown what the analysis on the derived models can reveal about the original models.