Showing papers on "Process architecture published in 2003"
23 Jun 2003
TL;DR: The design principles, the basic concepts, and the underlying XML technology of PNML are discussed to stimulate discussion on and contributions to a standard Petri net interchange format.
Abstract: The Petri Net Markup Language (PNML) is an XML-based interchange format for Petri nets. In order to support different versions of Petri nets and, in particular, future versions of Petri nets, PNML allows the definition of Petri net types. Due to this flexibility, PNML is a starting point for a standard interchange format for Petri nets. This paper discusses the design principles, the basic concepts, and the underlying XML technology of PNML. The main purpose of this paper is to disseminate the ideas of PNML and to stimulate discussion on and contributions to a standard Petri net interchange format.
391 citations
23 Jun 2003
TL;DR: CPN Tools is a tool for editing, simulating and analysing Coloured Petri Nets, which is based on advanced interaction techniques, such as toolglasses, marking menus, and bi-manual interaction.
Abstract: CPN Tools is a tool for editing, simulating and analysing Coloured Petri Nets. The GUI is based on advanced interaction techniques, such as toolglasses, marking menus, and bi-manual interaction. Feedback facilities provide contextual error messages and indicate dependency relationships between net elements. The tool features incremental syntax checking and code generation which take place while a net is being constructed. A fast simulator efficiently handles both untimed and timed nets. Full and partial state spaces can be generated and analysed, and a standard state space report contains information such as boundedness properties and liveness properties. The functionality of the simulation engine and state space facilities are similar to the corresponding components in Design/CPN, which is a widespread tool for Coloured Petri Nets.
360 citations
01 Jan 2003
TL;DR: This talk presents the personal view of the current status of highlevel Petri nets, in particular Coloured Petri Nets, and the main challenges that need to be addressed.
Abstract: This talk presents my personal view of the current status of highlevel Petri Nets, in particular Coloured Petri Nets. What have we achieved over the last 25 years and what are the main challenges that need to be addressed in order to make high-level Petri nets more useful, e.g., to the software industry? What kind of language extensions and tool support do we need to make Petri net modelling, simulation and analysis accessible to the knowledgeable engineer? I will also briefly discuss the main areas which I believe are the most obvious candidates for further theoretical development.
168 citations
07 Apr 2003
TL;DR: The construction improves a previous proposal by Yoneda and Ryuba of some state space abstractions for Time Petri nets and preserves their branching time temporal properties.
Abstract: This paper is concerned with construction of some state space abstractions for Time Petri nets. State class spaces were introduced long ago by Berthomieu and Menasche as finite representations for the typically infinite state spaces of Time Petri nets, preserving their linear time temporal properties. This paper proposes a similar construction that preserves their branching time temporal properties. The construction improves a previous proposal by Yoneda and Ryuba. The method has been implemented, computing experiments are reported.
147 citations
TL;DR: This review provides a very brief summary of these interesting new research directions in the mathematical structures known as Petri Nets.
Abstract: The mathematical structures known as Petri Nets have recently become the focus of much research effort in both the structural and quantitative analysis of all kinds of biological networks. This review provides a very brief summary of these interesting new research directions.
132 citations
TL;DR: Four case studies where coloured Petri Nets and their supporting computer tools have been used in system development projects with industrial partners are presented to illustrate different application areas of CP-nets in various phases of system development.
Abstract: Coloured Petri Nets (CP-nets or CPNs) and their supporting computer tools have been used in a wide range of application areas such as communication protocols, software designs, and embedded systems. The practical application of CP-nets has also covered many phases of system development ranging from requirements to design, validation, and implementation. This paper presents four case studies where CP-nets and their supporting computer tools have been used in system development projects with industrial partners. The case studies have been selected such that they illustrate different application areas of CP-nets in various phases of system development.
96 citations
TL;DR: It is concluded that Petri nets cannot model workflows accurately, unless they are extended with a syntax and semantics for reactivity, whereas the semantics of UMLact ivity diagrams models open, reactive systems.
Abstract: Petri net variants are widely used as a workflow modelling technique. Recently, UMLa ctivity diagrams have been used for the same purpose, even though the syntax and semantics of activity diagrams has not been yet fully worked out. Nevertheless, activity diagrams seem very similar to Petri nets and on the surface, one may think that they are variants of each other. To substantiate or deny this claim, we need to formalise the intended semantics of activity diagrams and then compare this with various Petri net semantics. In previous papers we have defined two formal semantics for UMLact ivity diagrams that are intended for workflow modelling. In this paper, we discuss the design choices that underlie these two semantics and investigate whether these design choices can be met in low-level and high-level Petri net semantics. We argue that the main difference between the Petri net semantics and our semantics of UML act ivity diagrams is that the Petri net semantics models resource usage of closed, active systems that are non-reactive, whereas our semantics of UMLact ivity diagrams models open, reactive systems. Since workflow systems are open, reactive systems, we conclude that Petri nets cannot model workflows accurately, unless they are extended with a syntax and semantics for reactivity.
93 citations
Journal Article•
TL;DR: This survey/tutorial discusses the need for formal methods in BPM and focuses on the verification of workflow processes using Petri-net-based results to address some of the challenges posed by BPM.
Abstract: Most scientists working on formal methods are mainly focusing on technical systems such as circuit design, embedded systems, traffic control, etc. Few are working on the application of formal methods to business processes. As a result, interesting problems in the domain of Business Process Manage- ment (BPM) are not addressed. To stimulate the application of formal methods to BPM, the following two conferences, taking place in June 2003, are co-located: (1) the International Conference on Applications and Theory of Petri nets (Petri nets 2003) (8) and (2) the International Conference on Business Process Manage- ment: On the Application of Formal Methods to Process-Aware Information Sys- tems (BPM 2003) (13). Both conferences precede the International Colloquium on Automata, Languages and Programming (ICALP 2003) also taking place in Eindhoven (The Netherlands). By co-locating these events we hope to trigger cooperation between people working on BPM and formal methods. This survey/tutorial discusses the need for formal methods in BPM. Although different formal methods could be applied in this domain, we focus on the appli- cation of Petri nets in this domain. In particular, we focus on the verification of workflow processes using Petri-net-based results. By this we hope to stimulate scientists working on Petri nets to address some of the challenges posed by BPM.
62 citations
TL;DR: A new class of PNs, Buffer-nets, for defining FMS is proposed, which enhances the modelling techniques for manufacturing systems with features that are considered difficult to model.
61 citations
17 Nov 2003
TL;DR: Petri nets are a graph-based tool and this work has shown that the Petri net incidence matrix captures the relationships between the infrastructure components and the place invariants have been shown to model the interdependencies and identify vulnerabilities.
Abstract: The infrastructure of many nations has become a very complex inter-connection of electric power distribution systems, oil and natural gas production facilities, transportation (pipelines) of these products, water supplies, and communications. In addition, each of these systems is intertwined and heavily dependent on each other. The challenge is to model these interdependencies, identify vulnerabilities, and determine specific recovery strategies. This paper demonstrates the use of Petri nets for addressing this challenge. Petri nets are a graph-based tool and this work has shown that the Petri net incidence matrix captures the relationships between the infrastructure components. The place invariants (P-invariants) have been shown to model the interdependencies and identify vulnerabilities. The transition invariants (T-invariants) determine specific recovery strategies. In addition, the graphical nature of Petri nets allows a simple visualization of the interdependencies by observation of the token flows through the net.
59 citations
TL;DR: It is shown how the time factor can be added as an integral part of the models of transitions and places, and the formalism of the extended net is introduced and studied in depth.
TL;DR: F fuzzy rules are referred to as the rules with certainty factors, the degree of truth is computed in an algebraic form based on state equation which can be implemented in matrix computation in Petri nets and can be transformed as the liner equation problems that can be solved in parallel.
Abstract: In this paper, we propose a Petri nets formalism for the verification of rule-based systems. Typical structural errors in a rule-based system are redundancy, inconsistency, incompleteness, and circularity. Since our verification is based on Petri nets and their incidence matrix, we need to transform rules into a Petri nets first, then derive an incidence matrix from the net. In order to let fuzzy rule-based systems detect above the structural errors, we are presenting a Petri-nets-based mechanism. This mechanism consists of three phases: rule normalization, rules transformation, and rule verification. Rules will be first normalized into Horn clauses, then transform the normalized rules into a high-level Petri net, and finally we verify these normalized rules. In addition, we are presenting our approach to simulate the truth conditions which still hold after a transition firing and negation in Petri nets for rule base modeling. In this paper, we refer to fuzzy rules as the rules with certainty factors, the degree of truth is computed in an algebraic form based on state equation which can be implemented in matrix computation in Petri nets. Therefore, the fuzzy reasoning problems can be transformed as the liner equation problems that can be solved in parallel. We have implemented a Petri nets tool to realize the mechanism presented fuzzy rules in this paper.
TL;DR: The controlled Petri net model obtained is maximally permissive while guaranteeing that forbidden states do not occur and the proposed method is computationally efficient and does not suffer from the state explosion problem.
Abstract: This paper describes a method for constructing a Petri-net-based controller for a discrete event system (DES) modelled by a Petri net. Assuming that an uncontrolled Petri net model of the DES and a set of forbidden state specifications are given, feedback control elements, i.e. a set of places and related transitions, with initial marking, are computed using the theory of regions, which is a formal synthesis technique for deriving Petri nets from automaton-based models. When feedback control elements are added to the uncontrolled Petri net model, the controlled (closed-loop) Petri net model of the system is obtained. The controlled Petri net model obtained is maximally permissive while guaranteeing that forbidden states do not occur. The proposed method is computationally efficient and does not suffer from the state explosion problem. Two examples are provided to show the applicability of the proposed method.
01 Apr 2003
TL;DR: A reinforcement learning algorithm for the high-level fuzzy Petri net (HLFPN) models in order to perform structure and parameter learning simultaneously and is able to learn faster due to its structural reduction.
Abstract: The author has developed a reinforcement learning algorithm for the high-level fuzzy Petri net (HLFPN) models in order to perform structure and parameter learning simultaneously. In addition to the HLFPN itself, the difference and similarity among a variety of subclasses concerning Petri nets are also discussed. As compared with the fuzzy adaptive learning control network (FALCON), the HLFPN model preserves the advantages that: 1) it offers more flexible learning capability because it is able to model both IF-THEN and IF-THEN-ELSE rules; 2) it allows multiple heterogeneous outputs to be drawn if they exist; 3) it offers a more compact data structure for fuzzy production rules so as to save information storage; and 4) it is able to learn faster due to its structural reduction. Finally, main results are presented in the form of seven propositions and supported by some experiments.
07 Apr 2003
TL;DR: In this paper, the authors define branching processes and unfoldings of high-level Petri nets and propose an algorithm which builds finite and complete prefixes of such unfoldings, which is often better than the usual explicit construction of the intermediate low-level net.
Abstract: In this paper, we define branching processes and unfoldings of high-level Petri nets and propose an algorithm which builds finite and complete prefixes of such unfoldings. The advantage of our method is that it avoids a potentially expensive translation of a high-level Petri net into a low-level one. The approach is conservative as all the verification tools employing the traditional unfoldings can be reused with prefixes derived directly from high-level nets. We show that this is often better than the usual explicit construction of the intermediate low-level net.
01 Sep 2003
TL;DR: This paper provides an examples-driven perspective on Petri nets from a manufacturing applications domain, and not only complete examples from the application domain are considered.
Abstract: There exists ample literature on Petri nets and its potential in the modelling, analysis, synthesis and implementation of systems in the manufacturing applications domain (see for example [54, 15, 18]; besides, in [66] an important bibliography is presented). This paper provides an examples-driven perspective. Nevertheless, not only complete examples from the application domain are considered. Manufacturing systems are frequently large systems, and conceptual complexity often appears because of some particular “local” constructions.
23 Jun 2003
TL;DR: In this paper, a distributed version of the Diagnoser Approach for discrete-event systems modeled by automata is adapted and extended to on-line fault diagnosis of system modeled by Petri nets, resulting in a centralized diagnosis algorithm based on the notion of Petri net diagnosers.
Abstract: The problem of detecting and isolating fault events in dynamic systems modeled as discrete-event systems is considered. The modeling formalism adopted is that of Petri nets with labeled transitions, where some of the transitions are labeled by different types of unobservable fault events. The Diagnoser Approach for discrete-event systems modeled by automata developed in earlier work is adapted and extended to on-line fault diagnosis of systems modeled by Petri nets, resulting in a centralized diagnosis algorithm based on the notion of "Petri net diagnosers". A distributed version of this centralized algorithm is also presented. This distributed version assumes that the Petri net model of the system can be decomposed into two place-bordered Petri nets satisfying certain conditions and that the two resulting Petri net diagnosers can exchange messages upon the occurrence of observable events. It is shown that this distributed algorithm is correct in the sense that it recovers the same diagnostic information as the centralized algorithm. The distributed algorithm provides an approach for tackling fault diagnosis of large complex systems.
01 Jan 2003
TL;DR: This contribution provides a thorough survey of the work of the authors on rule-based refinement of Petri nets in a compact form leaving out the technical details.
Abstract: This contribution provides a thorough survey of our work on rule-based refinement. Rule-based refinement comprises the transformation of Petri nets using rules while preserving certain system properties. Petri net rules and transformations are expressed by morphisms and pushouts. This allows an abstract formulation of our notions independent of a specific Petri net class, as place/transition nets, elementary nets, predicate/transition nets etc. Hence, it is adequate to consider our approach as rule-based refinement of Petri nets in general. We have presented various results in recent years at different conferences. So this contribution gives an overview of our work in a compact form leaving out the technical details.
10 Nov 2003
TL;DR: Results show the applicability of the proposed methodology, using ordinary t-timed Petri nets for modeling, analysis and synthesis of random topology production systems and networks.
Abstract: Ordinary t-timed Petri nets are used for modeling, analysis and synthesis of random topology production systems and networks. Each production system is first decomposed into production line (transfer chain), assembly, disassembly and parallel machines modules and then their corresponding modular Petri net models are derived. The overall system PN model is obtained via synthesis of the generic modules satisfying system constraints. P- and T-invariants are calculated and given a random topology production system, the total number of the system PN model nodes (places, transitions) is calculated from the corresponding generic PN modules. Results show the applicability of the proposed methodology.
01 Jan 2003
TL;DR: A method of Fuzzy Petri Nets(FPN) knowledge representation and its rigorous inference algorithm are proposed and it is proved that this method is very fast and accurate.
Abstract: As a graph tool, Petri nets can be used to describe most of the relations and behaviors in the discrete event dynamic system. As a mathematical tool, the analysis of behavior properties and performance evaluation can be done conveniently, using net theory and algebraic theory. So it is applied in the field of artificial intelligence more and more widely. A method of Fuzzy Petri Nets(FPN) knowledge representation and its rigorous inference algorithm are proposed in this paper. Fuzzy knowledge representation and matrix operation algorithm of inference using Fuzzy Petri Nets are discussed. For the first time Fuzzy Petri Net is applied in electric power transformer, and it represents relations between fault symptoms and faults. Additionally, conventional expert systems applied to fault diagnosis need to manually build complicated knowledge databases, but Fuzzy Petri Net is very simple and clear. Because it only uses simple matrix calculation based on Petri nets theory, fast and accurate results are obtained. Finally the method of Fuzzy Petri Nets is tested by the application of some samples. It is proved that this method is very fast and accurate .
TL;DR: The power hierarchy of dependability models developed by Malhotra and Trivedi (1994) and Muppala et al .
TL;DR: A methodology for modeling and simulating product development process-based on the extended stochastic high-level evaluation Petri nets (ESHLEP-N) and results show that the simulation procedure and the scheduling rules are effective.
Abstract: This paper presents a methodology for modeling and simulating product development process-based on the extended stochastic high-level evaluation Petri nets (ESHLEP-N). A product development process is composed of many design activities and the ESHLEP-N model can describe some special features of design activity in detail, such as randomness of its duration, uncertainty of its interruption and complexity of design iteration. Therefore, the ESHLEP-N model is employed to simulate a product development process. The initial product development plan obtained by a mathematical method beforehand is taken as the input of the simulation. Then the simulation procedure is proposed, along with four types of rules, i.e. activity-sequencing rules, resource-assigning rules, state-changing rules and the simulation-terminating rule, for scheduling the design activities. An example of the development process of an automobile drive system in concurrent engineering environment is presented to illustrate the method of the ESHLEP-N-based modeling, simulation procedure and scheduling rules. The simulation results show that the simulation procedure and the scheduling rules are effective.
09 Jun 2003
TL;DR: A formal security model, Secure Coloured Petri - using coloured Petri net's semantics - is proposed and it is shown how the enterprise security management system may take advantage of the proposed model's properties.
Abstract: The paper addresses important problems met when implementing mandatory access control policies in complex distributed systems (e.g. enterprise networks). The role of formal security models is also presented and the properties of the model suitable for systems under consideration are defined. Then a formal security model, Secure Coloured Petri - using coloured Petri net's semantics - is proposed. It is shown how the enterprise security management system may take advantage of the proposed model's properties. Application of coloured Petri nets analysis and construction methods to information flow security analysis is also proposed and discussed.
02 Jul 2003
TL;DR: The expressive capabilities of the model and the type of results that can be derived through symbolic enumeration of its dense-timed state space are illustrated with reference to a flexible system mixing dynamic acceptance and performance polymorphism.
Abstract: Preemptive Time Petri nets are obtained by extending Time Petri nets with an additional mechanism of resource assignment which makes the progress of timed transitions be dependent on the availability of a set of preemptable resources, and with the capability to make transition times and priorities be dependent on the marking. The combination of these capabilities supports description and verification of flexible real time systems running under preemptive scheduling, with periodic, sporadic and one shot processes, with non-deterministic execution times, with semaphore synchronizations and precedence relations deriving from internal task sequentialization and from interprocess communication. The expressive capabilities of the model and the type of results that can be derived through symbolic enumeration of its dense-timed state space are illustrated with reference to a flexible system mixing dynamic acceptance and performance polymorphism.
01 Sep 2003
TL;DR: Software engineering and Petri net theory are disciplines of different nature that investigate applications and properties of a specific model (Petri nets) and try to find a coherent set of solutions to cope with the different aspects of the problem.
Abstract: Software engineering and Petri net theory are disciplines of different nature. Research on software engineering focuses on a problem domain, i.e., the development of complex software systems, and tries to find a coherent set of solutions to cope with the different aspects of the problem, while research on Petri nets investigates applications and properties of a specific model (Petri nets).
10 Nov 2003
TL;DR: The main contribution of this study shows how diagnosers and verifiers for systems modeled by Petri net are constructed accordingly, as shown by examples, the additional information from observed transitions adds diagnosability to the system.
Abstract: Failure diagnosis in the context of DES was first formulated by Sampath et al Where the notion of diagnosability and the associated diagnoser are proposed Ushio et al extended Sampath's study to systems modeled by Petri nets This paper further assumes some of the transitions in a Petri net model are observable in the sense that its occurrence can be observed The main contribution of this study shows how diagnosers and verifiers for systems modeled by Petri net are constructed accordingly As shown by examples, the additional information from observed transitions adds diagnosability to the system
TL;DR: The special structure in these transition systems of Petri nets is exploited to provide an exact and closed-form characterization of all its inductive linear invariants and an invariant generation technique that is shown to be efficient and powerful in practice.
Abstract: Petri nets have been widely used to model and analyze concurrent systems. Their wide-spread use in this domain is, on one hand, facilitated by their simplicity and expressiveness. On the other hand, the analysis of Petri nets for questions like reachability, boundedness and deadlock freedom can be surprisingly hard. In this paper, we model Petri nets as transition systems. We exploit the special structure in these transition systems to provide an exact and closed-form characterization of all its inductive linear invariants. We then exploit this characterization to provide an invariant generation technique that we demonstrate to be efficient and powerful in practice. We compare our work with those in the literature and discuss extensions.
19 Dec 2003
TL;DR: A new approach via programmable logic controller (PLC) and Petri net synthesis is proposed and shown that the method has many advantages at improving flexibility and troubleshoots of system and reducing the difficulty in its realization.
Abstract: Traffic lights are commonly used in the intersection in urban areas nowadays. In fact a network of the traffic lights regulating the urban vehicle can be viewed as a complex discrete-event system (DES). It is proved that Petri nets are one of the methodologies for modeling, analyzing and controlling on DES. A new approach via programmable logic controller (PLC) and Petri net synthesis is proposed in this paper. Firstly, we described the typical urban traffic lights control using Petri nets. Having compared with three methods for Petri nets realization, the best implementation method of the traffic lights control system was one which made with the PLC. The sequential function chart (SFC) of the PLC system is also given in the thesis. The result shown that the method has many advantages at improving flexibility and troubleshoots of system and reducing the difficulty in its realization.
TL;DR: This paper shows how an extension of time Petri nets proposed in (Roux and Deplanche, 2002), scheduling extended timepetri nets (SETPN), is especially well adapted for the modelisation of realtime systems and particularly embedded systems and provides a method for computing the state space of SETPN.
Journal Article•
TL;DR: This paper introduces the concept of Algebraic Higher-Order Nets, which allow to have dynamical tokens like graphs or (ordinary low-level) Petri nets, which are specified in the higher-order algebraic specification language HasCasl such that graphs and Petrinets become first-class citizens.
Abstract: Petri nets and Algebraic High-Level Nets are well-known to model parallel and concurrent systems. In this paper, we introduce the concept of Algebraic Higher-Order Nets, which allow to have dynamical tokens like graphs or (ordinary low-level) Petri nets. For this purpose, we specify graphs and Petri nets in the higher-order algebraic specification language HASCASL such that graphs and Petri nets become first-class citizens, i.e. members of algebras (rather than algebras themselves). As an example, we model hospital therapeutic processes by a single higher-order net. Individual care plans for each patient are tokens modeled by low-level nets.