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Showing papers on "Process architecture published in 2001"


Journal ArticleDOI
TL;DR: A way of mapping workflow into Petri nets, which can be used as a basis for such systems as well as an agreed and standard modelling technique.

327 citations


Journal ArticleDOI
TL;DR: This paper is a survey of the work of the authors' team on hybridPNs (definition, properties, modeling), and contains new material such as the definition of extended hybrid PNs and several applications, explanations and comments about the timings in Petri nets, more on the conflict resolution in Hybrid PNs, and connection between hybrid PN and hybrid automata.
Abstract: Petri nets (PNs) are widely used to model discrete event dynamic systems (computer systems, manufacturing systems, communication systems, etc). Continuous Petri nets (in which the markings are real numbers and the transition firings are continuous) were defined more recently; such a PN may model a continuous system or approximate a discrete system. A hybrid Petri net can be obtained if one part is discrete and another part is continuous. This paper is basically a survey of the work of the authors' team on hybrid PNs (definition, properties, modeling). In addition, it contains new material such as the definition of extended hybrid PNs and several applications, explanations and comments about the timings in Petri nets, more on the conflict resolution in hybrid PNs, and connection between hybrid PNs and hybrid automata. The paper is illustrated by many examples.

249 citations


01 Jan 2001
TL;DR: This contribution concentrates on those features where Petri nets significantly differ from other modeling languages, i.e. where the use of Petrinets leads to advantages compared to other languages.
Abstract: The increasing number of Petri net variants naturally leads to the question whether the term "Petri net" is more than a common name for very different concepts. This contribution tries to identify aspects common to all or at least to most Petri nets. It concentrates on those features where Petri nets significantly differ from other modeling languages, i.e. we ask where the use of Petri nets leads to advantages compared to other languages. Different techniques that are usually comprised under the header "analysis" are distinguished with respect to the analysis aim. Finally, the role of Petri nets in the development of distributed systems is discussed.

163 citations


Book
01 Jan 2001
TL;DR: This book presents a step-by-step development of a rigorous framework for the specification and verification of concurrent systems and takes its inspiration and methods from Process Algebra and Petri Nets, two prominent branches of concurrency theory.
Abstract: This book presents a step-by-step development of a rigorous framework for the specification and verification of concurrent systems. Petri Net Algebra takes its inspiration and methods from Process Algebra and Petri Nets, two prominent branches of concurrency theory. Added synergistic benefit is derived from combining their respective advantages. Petri nets are treated as composable objects, and as such they are embedded in a general process algebra. A generic process algebra is given an automatic Petri net semantics so that net-based verification techniques, based on structural invariants and causal partial orders, can be applied to the process algebra. Finally, the theory is applied to a realistic concurrent programming language. The book contains full proofs, carefully chosen examples and several possible directions for further research. A unique aspect is that the development of the Petri net algebra is handled so as to allow for further applications-oriented extensions and modifications.

139 citations


BookDOI
01 May 2001
TL;DR: In this paper, the CO-OPN/2 formalism is used to specify a Petri Net with high-level Petri Nets for the specification of a groupware editing tool.
Abstract: Section I.- Object Oriented Modelling with Object Petri Nets.- Using Petri Nets for Specifying Active Objects and Generative Communication.- Object-Oriented Nets with Algebraic Specifications: The CO-OPN/2 Formalism.- CLOWN as a Testbed for Concurrent Object-Oriented Concepts.- Concurrency in Communicating Object Petri Nets.- Object Orientation in Hierarchical Predicate Transition Nets.- CoOperative Objects: Principles, Use and Implementation.- OB(PN)2: An Object Based Petri Net Programming Notation.- On Formalizing UML with High-Level Petri Nets.- Section II.- Modeling a Groupware Editing Tool with Cooperative Objects.- Modelling Constrained Geometric Objects with OBJSA Nets.- An Object-Based Modular CPN Approach: Its Application to the Specification of a Cooperative Editing Environment.- KRON: Knowledge Engineering Approach Based on the Integration of CPNs with Objects.- Modeling of a Library with THORNs.- Inheritance of Dynamic Behavior Development of a Groupware Editor.- Object Coloured Petri Nets - A Formal Technique for Object Oriented Modelling.- Section III.- An Actor Algebra for Specifying Distributed Systems: The Hurried Philosophers Case Study.- Formal Reasoning about Actor Programs Using Temporal Logic.- Flexible Types for a Concurrent Model.- High Level Transition Systems for Communicating Agents.- Schedulability Analysis of Real Time Actor Systems Using Coloured Petri Nets.- Control Properties in Object-Oriented Specifications.- Case Studies.- A Cooperative Petri Net Editor.- The Hurried Philosophers.

127 citations


Journal ArticleDOI
TL;DR: In this paper, a methodology is developed which uses Petri nets instead of the fault tree methodology and solves for reliability indices utilising fuzzy Lambda-Tau method, which allows expert opinions, linguistic variables, operating conditions, uncertainty and imprecision in reliability information to be incorporated into the system model.

126 citations


Book ChapterDOI
01 Jan 2001
TL;DR: In this paper, the authors try to identify aspects common to all or at least to most Petri nets, focusing on those features where Petri net significantly differ from other modeling languages.
Abstract: The increasing number of Petri net variants naturally leads to the question whether the term “Petri net” is more than a common name for very different concepts This contribution tries to identify aspects common to all or at least to most Petri nets It concentrates on those features where Petri nets significantly differ from other modeling languages, ie we ask where the use of Petri nets leads to advantages compared to other languages Different techniques that are usually comprised under the header “analysis” are distinguished with respect to the analysis aim Finally, the role of Petri nets in the development of distributed systems is discussed

100 citations


Book ChapterDOI
25 Jun 2001
TL;DR: This paper skips the topic of agent platforms and handles the agent structure briefly to introduce a key concept of the work: the graphical modelling of the behaviour of autonomous and adaptive agents in terms of Petri net protocols.
Abstract: This work proposes a way to model the structure and behaviour of agents in terms of executable coloured Petri net protocols. Structure and behaviour are not all aspects of agent based computing: agents need a world to live in (mostly divided into platforms), they need a general structure (e.g. including a standard interface for communication) and their own special behaviour. Our approach tackles all three parts in terms of Petri nets. This paper skips the topic of agent platforms and handles the agent structure briefly to introduce a key concept of our work: the graphical modelling of the behaviour of autonomous and adaptive agents. A special kind of coloured Petri nets is being used throughout the work: reference nets. Complex agent behaviour is achieved via dynamic composition of simpler sub-protocols, a task that reference nets are especially well suited for. The inherent concurrency of Petri nets is another point that makes it easy to model agents: multiple threads of control are (nearly) automatically implied in Petri nets.

91 citations


Journal ArticleDOI
Ming Dong1, F. Frank Chen1
TL;DR: In this article, the authors present a systematic methodology for modeling and analysis of manufacturing supply chain business processes, which employs Computer Integrated Manufacturing Open System Architecture (CIMOSA) behavior rules to model the business process routing structures.
Abstract: This paper presents a systematic methodology for modeling and analysis of manufacturing supply chain business processes. The proposed approach first employs Computer Integrated Manufacturing Open System Architecture (CIMOSA) behavior rules to model the business process routing structures of manufacturing supply chain networks. Object-oriented predicate/transition nets (OPTNs) are then developed for the modular modeling and analysis of process models. Based on the structure of OPTNs, a procedure to obtain the system's P -invariants through objects’ P -invariants is suggested. From the P -invariants obtained, system structural properties such as deadlock and overflow can be analyzed. By using Petri net unfolding techniques and by extracting the process model of each object from the entire process model, the sequencing analysis for operations in supply chain processes becomes possible. Several manufacturing supply chain examples are used to illustrate the effectiveness of the proposed method.

88 citations


Book ChapterDOI
01 Jan 2001
TL;DR: A rewriting semantics is defined that maps place/transition nets into rewriting logic specifications and is connected to the model-theoretic semantics of rewriting logic in the sense of natural isomorphisms between suitable functors.
Abstract: We propose rewriting logic as a unifying framework for a wide range of Petri nets models. We treat in detail place/transition nets and important extensions of the basic model by individual tokens, test arcs, and time. Based on the idea that "Petri nets are monoids" suggested by Meseguer and Montanari we define a rewriting semantics that maps place/transition nets into rewriting logic specifications. We furthermore generalize this result to a general form of algebraic net specifications subsuming also colored Petri nets as a special case. The soundness and completeness results we state relate the commutative process semantics of Petri nets proposed by Best and Devillers to the model-theoretic semantics of rewriting logic in the sense of natural isomorphisms between suitable functors. In addition we show how place/transition nets with test arcs and timed Petri nets can be equipped with a rewriting semantics and discuss how other extensions can be treated along similar lines. Beyond the conceptual unification of quite different kinds of Petri nets within a single framework, the rewriting semantics can provide a guide for future extensions of Petri nets and help to cope with the growing diversity of models in this field. On the practical side, a major application of the rewriting semantics is its use as a logical and operational representation of Petri net models for formal verification and for the efficient execution and analysis using a rewriting engine such as Maude, which also allows us to specify different execution and analysis strategies in the same rewriting logic language by means of reflection.

85 citations


Journal ArticleDOI
TL;DR: This paper presents a symbolic approach for the analysis of bounded Petri nets and shows how large reachability sets can be generated, represented, and analyzed with moderate BDD sizes.
Abstract: This paper presents a symbolic approach for the analysis of bounded Petri nets. The structure and behavior of the Petri net is symbolically modeled by using Boolean functions, thus reducing reasoning about Petri nets to Boolean calculation. The set of reachable markings is calculated by symbolically firing the transitions in the Petri net. Highly concurrent systems suffer from the state explosion problem produced by an exponential increase of the number of reachable states. This state explosion is handled by using Binary Decision Diagrams (BDDs) which are capable of representing large sets of markings with small data structures. Petri nets have the ability to model a large variety of systems and the flexibility to describe causality, concurrency, and conditional relations. The manipulation of vast state spaces generated by Petri nets enables the efficient analysis of a wide range of problems, e.g., deadlock freeness, liveness, and concurrency. A number of examples are presented in order to show how large reachability sets can be generated, represented, and analyzed with moderate BDD sizes. By using this symbolic framework, properties requiring an exhaustive analysis of the reachability graph can be efficiently verified.

Journal ArticleDOI
TL;DR: Petri-net-aided software including genetic-algorithm-based search and heuristics is described to deal with a multi-mode, multi-constrained scheduling problem with pre-emption of activities.
Abstract: Multi-mode and multi-resource constrained scheduling of a project is a complex task. This paper addresses the use of a Petri net as a modelling and scheduling tool in this context, t The benefits of Petri nets in project scheduling are discussed. We propose extensions to Petri nets to suit scheduling of activities in a decision CPM. We also propose the use of a P-matrix for token movements in Petri nets. A genetic algorithm is used to find a better solution. Petri-net-aided software including genetic-algorithm-based search and heuristics is described to deal with a multi-mode, multi-constrained scheduling problem with pre-emption of activities.

Book ChapterDOI
TL;DR: This paper gives a precise definition of the basic model together with a suitable process semantics of complex systems modelled close to their real appearance in a natural way to promote clear and reliable concepts.
Abstract: Objects are studied as higher-level net tokens having an individual dynamical behaviour. In the context of Petri net research it i s quite natural to also model such tokens by Petri nets. To distinguish them from the system net, they are called object nets. Object nets behave like tokens, i.e., they are lying in places and are moved by transitions. In contrast to ordinary tokens, however, they may change their state (i.e. their marking) when lying in a place or when being moved by a transition. By this approach an interesting and challenging two-level system modelling technique is introduced. Similar to the object-oriented approach, complex systems are modelled close to their real appearance in a natural way to promote clear and reliable concepts. Applications in fields like workflow, agent-oriented approaches (mobile agents and/or intelligent agents as in AI research) or open system networks are feasible. This paper gives a precise definition of the basic model together with a suitable process semantics. The focus is set more on basic concepts and their fundamental study than on high modelling capability.

Book ChapterDOI
20 Aug 2001
TL;DR: Improvements to the existing algorithms for generating finite complete prefixes of net unfoldings are proposed, demonstrating that one can achieve significant speedups when transition presets of a net being unfolded have overlapping parts.
Abstract: Model checking based on the causal partial order semantics of Petri nets is an approach widely applied to cope with the state space explosion problem. One of the ways to exploit such a semantics is to consider (finite prefixes of) net unfoldings, which contain enough information to reason about the reachable markings of the original Petri nets. In this paper, we propose several improvements to the existing algorithms for generating finite complete prefixes of net unfoldings. Experimental results demonstrate that one can achieve significant speedups when transition presets of a net being unfolded have overlapping parts.

Journal Article
TL;DR: This paper considers multi-level and recursive NP-nets, for which decidability of termination and some other properties are proved, and compares them with other Petri net models.
Abstract: Nested Petri nets (NP-nets) is a formalism for modeling hierarchical multi-agent systems. Tokens in nested Petri nets are elements represented by nets themselves. The paper continues investigating semantic properties of NP-nets, started in [10], where two-level NP-nets were studied. Here we consider multi-level and recursive NP-nets, for which decidability of termination and some other properties are proved. A comparison of NP-nets with other Petri net models is given.

Journal ArticleDOI
TL;DR: The motivation, the concepts, and the implementation of the Petri Net Kernel are discussed, which relieves the programmer of a Petri net tool from implementing standard operations on Petri nets and a graphical user interface.
Abstract: The Petri Net Kernel is an infrastructure for building Petri net tools. It relieves the programmer of a Petri net tool from implementing standard operations on Petri nets and a graphical user interface. In this paper, we discuss the motivation, the concepts, and the implementation of the Petri Net Kernel.

Book ChapterDOI
20 Aug 2001
TL;DR: This work defines a truly concurrent semantics for open nets by extending the Goltz-Reisig process semantics of Petri nets, and introduces a composition operation over open nets, characterized as a pushout in the corresponding category, suitable to model both interaction through open places and synchronization of transitions.
Abstract: In order to model the behaviour of open concurrent systems by means of Petri nets, we introduce open Petri nets, a generalization of the ordinary model where some places, designated as open, represent an interface of the system towards the environment. Besides generalizing the token game to reflect this extension, we define a truly concurrent semantics for open nets by extending the Goltz-Reisig process semantics of Petri nets.We introduce a composition operation over open nets, characterized as a pushout in the corresponding category, suitable to model both interaction through open places and synchronization of transitions. The process semantics is shown to be compositional with respect to such composition operation. Technically, our result is similar to the amalgamation theorem for data-types in the framework of algebraic specifications. A possible application field of the proposed constructions and results is the modeling of interorganizational workflows, recently studied in the literature. This is illustrated by a running example.

Journal ArticleDOI
TL;DR: This half-tutorial paper has shown how a fairly simple kind of Petri net, i.e., timed stochastic Petri nets, works in practice, and how they are superior to state graphs since they show state durations explicitly.
Abstract: One of the basic problems of dependability modeling is the adequate abstraction of real-world technological problems to the principle terms of reliability/safety scenarios. This concerns primarily the definition of components and of faults on different system levels. Given these terms the rest of any modeling needs basic logical operations, mostly AND and OR, and delays, and often some counting (of time or events). All of these basic operations are offered by a fairly simple kind of Petri net (PN), i.e., timed stochastic Petri nets, allowing also for the modeling of immediate activities and of such with a deterministic delay. In this half-tutorial paper it is shown how such Petri nets modeling, i.e., the construction of the relevant nets, works in practice. No math will be needed for that. Several typical engineering virtues are needed; primarily imagination as to how to (i) find simple solutions, since often nonelegant solutions can be correct too, (ii) compose larger PN from elementary building blocks, and (iii) the ability to model the real world by interpreting the so-called tokens of a PN intelligently in different places of one and the same PN. In the appendix it is shown how the PN can also help in the analytical analysis of nonrepairable systems. In that context they are superior to state graphs since they show state durations explicitly.

Journal ArticleDOI
I. Demongodin1
TL;DR: The complete formalism of Generalised Batches Petri nets is given through the definition of the model, the enabling and firing rules, the time analysis methods, and two examples illustratethese notions.
Abstract: Recently, the possibility of associating both discrete events and continuous time behaviour in the same formalism has generated a considerable interest in the Petri net paradigm. A central issue in this field is the concept of Hybrid Petri net which consists in continuous transitions and places holding non negative real number, and discrete transitions and places holding integer tokens. By adding a new type of nodes, batch transitions and batch places, Batches Petri nets have been defined. A batch node combines both a discrete event and a linear continuous dynamic behaviour in a single structure. Batches Petri nets can then be used in the control design and performance analysis of high-speed systems composed of continuous transfer elements which introduce variable delays on continuous flows. In this paper, the complete formalism of Generalised Batches Petri nets is given through the definition of the model, the enabling and firing rules, the time analysis methods, and two examples illustrate these notions.

Journal ArticleDOI
TL;DR: In this paper, a formal method (called PZ nets) for specifying concurrent and distributed systems is presented, which integrates two well-known existing formal methods Petri nets and Z such that Petri Nets are used to specify the overall structure, control flows, causal relation, and dynamic behavior of a system; and Z is used to define tokens, labels and constrains of the system.
Abstract: In this paper, a formal method (called PZ nets) for specifying concurrent and distributed systems is presented. PZ nets integrate two well-known existing formal methods Petri nets and Z such that Petri nets are used to specify the overall structure, control flows, causal relation, and dynamic behavior of a system; and Z is used to define tokens, labels and constrains of the system. The essence, benefits, and problems of the integration are discussed. A set of heuristics and transformations to develop PZ nets and a technique to analyze PZ nets are proposed and demonstrated through a well-known example.

Book ChapterDOI
25 Jun 2001
TL;DR: A state space method for Petri nets having a time concept based on a global clock and associating time stamps to tokens is presented and makes it possible to condense the usually infinite state space of such timed Petrinets into a finite state space without loosing analysis power.
Abstract: We present a state space method for Petri nets having a time concept based on a global clock and associating time stamps to tokens. The method is based on equivalence on states and makes it possible to condense the usually infinite state space of such timed Petri nets into a finite state space without loosing analysis power. The practical application of the method is demonstrated on a large example of an audio/video protocol by means of a computer tool implementing the method.

Book ChapterDOI
02 Apr 2001
TL;DR: It is proved that a join process is typeable according to Δi if and only if it is (strictly equivalent to) a net of class Πi, and a hierarchy of type systems of decreasing strictness is introduced.
Abstract: We study the expressiveness of the join calculus by comparison with (generalised, coloured) Petri nets and using tools from type theory More precisely, we consider four classes of nets of increasing expressiveness, Πi, introduce a hierarchy of type systems of decreasing strictness, Δi, i = 0, , 3, and we prove that a join process is typeable according to Δi if and only if it is (strictly equivalent to) a net of class Πi In the details, Π0 and Π1 contain, resp, usual place/transition and coloured Petri nets, while Π2 and Π3 propose two natural notions of high-level net accounting for dynamic reconfiguration and process creation and called reconfigurable and dynamic Petri nets, respectively

Journal ArticleDOI
01 May 2001
TL;DR: The main new result in this paper extends rule-based modification of algebraic highlevel nets such that it preserves safety properties formulated in terms of temporal logic, an important safety property of a medical information system is considered and is shown to be preserved underrule-based refinement.
Abstract: The concept of rule-based modification developed in the area of algebraic graph transformations and high-level replacement systems has recently shown to be a powerful concept for vertical stucturing of Petri nets. This includes low-level and high-level Petri nets, especially algebraic high-level nets which can be considered as an integration of algebraic specifications and Petri nets. In a large case study rule-based modification of algebraic high-level nets has been applied successfully for the requirements analysis of a medical information system. The main new result in this paper extends rule-based modification of algebraic highlevel nets such that it preserves safety properties formulated in terms of temporal logic. For software development based on rule-based modification of algebraic high-level nets as a vertical development strategy this extension is an important new technique. It is called rule-based refinement. As a running example an important safety property of a medical information system is considered and is shown to be preserved under rule-based refinement.


Journal Article
TL;DR: A comparison of methods using an example problem from a previous research shows that the method suggested is much simpler and more extendable than the previous one and the solutions obtained from the previous algorithm are not optimal in general.
Abstract: This paper considers the application of Petri nets with timestamps to the problem of disassembly scheduling with parts commonality, which is the problem of determining time and quantity of ordering the used product to fulfill the demands of individual disassembled parts. Unlike the simple case, parts commonality creates dependencies of components and makes them difficult to solve. A comparison of methods using an example problem from a previous research shows that the method suggested in this paper is much simpler and more extendable than the previous one. Also, we show that the solutions obtained from the previous algorithm are not optimal in general.

Book
01 Jan 2001
TL;DR: The Petri Net Model is used as a model for Structural Linear Algebraic Control Design, which automates the very labor-intensive and therefore time-heavy and expensive process of manually winding down and restarting petri nets.
Abstract: Preface. 1. The Petri Net Model. 2. Supervisory Control. 3. Uncontrollable Events and Transitions. 4. Reduction Theorems. 5. Acyclic Petri Nets. 6. Decomposition of the Control Design. 7. Continuous Versus Discrete Events. 8. Structural Linear Algebraic Control Design. References. Index.

Proceedings ArticleDOI
11 Sep 2001
TL;DR: The benefits of using multiple enabled transitions for extensions of Petri nets having quantitative notions of time and it is pointed out that what could be thought as a straightforward extension actually implies some subtle underlying semantic choices.
Abstract: This paper discusses and formalises the benefits of using multiple enabled transitions for extensions of Petri nets having quantitative notions of time It also points out that what could be thought as a straightforward extension actually implies some subtle underlying semantic choices As an example, a complete semantics for Merlin's (1974) time Petri nets is defined, based on the threshold notion

Proceedings ArticleDOI
25 Jun 2001
TL;DR: This paper describes a method for generating an executable prototype from a CO-OPN specification that fulfils the Java Beans component architecture, however the approach is also applicable to other object-oriented implementation languages with a component architecture.
Abstract: CO-OPN (Concurrent Object Oriented Petri Net) is a formal specification language for modelling distributed systems; it is based on coordinated algebraic Petri nets. We describe a method for generating an executable prototype from a CO-OPN specification. We focus our discussion on the generation of executable code for CO-OPN classes. CO-OPN classes are defined using Petri nets. The main problems arise when implementing synchronization and non-determinism of CO-OPN classes in procedural languages. Our method proposes a solution to these problems. Another interesting aspect of our method is the easy integration of a generated prototype into any existing system. This paper focuses on the generation of Java code that fulfils the Java Beans component architecture, however our approach is also applicable to other object-oriented implementation languages with a component architecture.

Journal ArticleDOI
TL;DR: The research results show that the proposed knowledge Petri net approach is applicable for design, simulation, analysis and evaluation, and even layout optimization of the flexible assembly system in an integrated intelligent environment.
Abstract: The integration of design and planning of flexible assembly system has been recognized as a tool for achieving efficient assembly in a production environment that demands assembly with a high degree of flexibility. This paper proposes a concurrent intelligent approach and framework for the design of robotic flexible assembly systems. The principle of the proposed approach is based on the knowledge Petri net formalisms, incorporating Petri nets with more general problem-solving strategies in AI using knowledge-based system techniques. The complex assembly systems are modeled and analyzed by adopting a formal representation of the system dynamic behaviors through knowledge Petri net modeling from the specifications and the analysis of those models. A template is first defined for a knowledge Petri net model, and then the models for assembly system individuals are established in the form of instances of the template. The design of assembly systems is implemented through a knowledge Petri net-based function–behavior–structure model. The research results show that the proposed knowledge Petri net approach is applicable for design, simulation, analysis and evaluation, and even layout optimization of the flexible assembly system in an integrated intelligent environment. The integration of assembly design and planning process can help reduce the development time of assembly systems.

Book ChapterDOI
18 Jul 2001
TL;DR: A new symbolic model checking algorithm for parameterized concurrent systems modeled as (Lossy) Petri Nets, and (L Lossy) Vector Addition Systems is proposed, based on a rich assertional language based on the graph-based symbolic representation of upward-closed sets introduced in [DR00].
Abstract: We propose a new symbolic model checking algorithm for parameterized concurrent systems modeled as (Lossy) Petri Nets, and (Lossy) Vector Addition Systems, based on the following ingredients: a rich assertional language based on the graph-based symbolic representation of upward-closed sets introduced in [DR00], the combination of the backward reachability algorithm of [ACJT96] lifted to the symbolic setting with a new heuristic rule based on structural properties of Petri Nets. We evaluate the method on several Petri Nets and parameterized systems taken from the literature [ABC+95, EM00, Fin93, MC99], and we compare the results with other finite and infinite-state verification tools.