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Showing papers on "Process architecture published in 1996"


01 Jan 1996
TL;DR: A new class of stochastic Petri nets in which one or more places can hold fluid rather than discrete tokens is introduced, and equations for their transient and steady-state behavior are provided.
Abstract: In this paper we introduce a new class of stochastic Petri nets in which one or more places can hold fluid rather than discrete tokens. We define a class of fluid stochastic Petri nets in such a way that the discrete and continuous portions may affect each other. Following this definition we provide equations for their transient and steady-state behavior. We present several examples showing the utility of the construct in communication network modeling and reliability analysis, and discuss important special cases. We then discuss numerical methods for computing the transient behavior of such nets. Finally, some numerical examples are presented.

190 citations


Book ChapterDOI
Kurt Jensen1
01 Sep 1996
TL;DR: The development of Coloured Petri Nets has been driven by the desire to develop a modelling language theoretically well-founded and versatile enough to be used in practice for systems of the size and complexity found in typical industrial projects.
Abstract: The development of Coloured Petri Nets (CP-nets or CPN) has been driven by the desire to develop a modelling language - at the same time theoretically well-founded and versatile enough to be used in practice for systems of the size and complexity found in typical industrial projects. To achieve this, we have combined the strength of Petri nets with the strength of programming languages. Petri nets provide the primitives for describing synchronisation of concurrent processes, while programming languages provide the primitives for definition of data types and manipulation of their data values.

167 citations


Journal ArticleDOI
TL;DR: This work proposes a framework based on high-level Petri nets that is used to model and analyse business processes and presents the “What, how and by whom?” approach, developed to guide the application of the framework in a BPR setting.

150 citations


01 Jan 1996
TL;DR: A model which provides a simple graphical representation of hybrid systems and takes advantage of the modular structure of Petri nets in giving a compact description of systems composed of interacting subsystems, both time-continuous and discrete-event.
Abstract: The paper presents a model which provides a simple graphical representation of hybrid systems and takes advantage of the modular structure of Petri nets in giving a compact description of systems composed of interacting subsystems, both time-continuous and discrete-event. The modelling formalism seems rich enough to encompass large classes of hybrid systems and can easily represent many of the features of the models given in the literature.

145 citations


Book
01 Jan 1996
TL;DR: In this article, Petri nets are used for qualitative properties modelling of manufacturing systems - modelling and analysis of common modules modelling, analysis and optimization of cyclic manufacturing systems acyclic systems answers to exercises and problems.
Abstract: Basics of petri nets qualitative properties modelling of manufacturing systems - modelling and analysis of common modules modelling, analysis and optimization of cyclic manufacturing systems acyclic systems answers to exercises and problems.

143 citations


Journal ArticleDOI
TL;DR: It is shown how to generate all elementary Petri nets corresponding to a given transition system, and it is proven that there always exists a small one which has only polynomially many elements in the size of the transition system.
Abstract: The synthesis problem of concurrent systems is the problem of synthesizing a concurrent system model from sequential observations. The paper studies the synthesis problem for elementary Petri nets and transition systems. A characterization of the class of transition systems which correspond to elementary Petri nets is proven. It is shown how to generate all elementary Petri nets corresponding to a given transition system. If there is any such elementary Petri net, it is proven that there always exists a small one which has only polynomially many elements in the size of the transition system.

142 citations


Book ChapterDOI
01 Sep 1996
TL;DR: The authors retraces, collects, and summarises contributions of the authors on the theme of Petri nets and their categorical relationships to other models of concurrency, such as concurrency models.
Abstract: This paper retraces, collects, and summarises contributions of the authors — in collaboration with others — on the theme of Petri nets and their categorical relationships to other models of concurrency.

102 citations


Journal ArticleDOI
TL;DR: In this paper, the authors use Petri net based tools and techniques to find conflicting and redundant precedences, upper and lower bounds for the makespan, etc., in the 10×10 problem.
Abstract: Timed Petri nets can be used to model and analyse scheduling problems. To support the modelling of scheduling problems, we provide a method to map tasks, resources and constraints onto a timed Petri net. By mapping scheduling problems onto Petri nets, we are able to use standard Petri net theory. In this paper we will show that we can use Petri net based tools and techniques to find conflicting and redundant precedences, upper- and lower-bounds for the makespan, etc. This is illustrated by a Petri net based analysis of the notorious 10×10 problem due to Fisher & Thompson (1963)

70 citations


Journal ArticleDOI
TL;DR: It is shown that the strong relationship between prime event structures and 1-safe Petri nets established in a categorical framework in Winskel (1987) can be extended to the present setting, provided the authors restrict their attention to the subclass of Petrinets whose behaviours do not exhibit any auto-concurrency.

68 citations


Journal ArticleDOI
TL;DR: A notion of equivalence among time Petri nets is introduced, and it is proved that the reduction rules extended to work with time petri nets yield equivalent nets.
Abstract: The goal of net reduction is to increase the effectiveness of Petri-netbased real-time program analysis. Petri-net-based analysis, like all reachabilitybased methods, suffers from the state explosion problem. Petri net reduction is one key method for combating this problem. In this paper, we extend several rules for the reduction of ordinary Petri nets to work with time Petri nets. We introduce a notion of equivalence among time Petri nets, and prove that our reduction rules yield equivalent nets. This notion of equivalence guarantees that crucial timing and concurrency properties are preserved.

64 citations


Proceedings Article
01 Jan 1996
TL;DR: In this article, structural analysis of P-time Petri nets is proposed to analyze the existence of a repetitive functioning mode in Petri net's, and a sufficient condition is given for the p-time Event Graph.
Abstract: P-time Petri Nets are convenient tools for modelling manufacturing system whose operations times are not precisely given, but are included between a minimum and a maximum value. For example, this is the case for electroplating lines, chemical industry. So, the typical feature of these nets is firing under compulsion. Properties analysis of the net associated with the manufacturing system can be performed by the establishment of the coverability tree. But this enumerative analysis approach is practically difficult to perform because we have, in general, combinatorial explosion of the state classes. In that sense, we propose an other way to analyse this net : structural analysis. The aim of this approach is to give analytic necessary conditions to exhibit the existence of a repetitive functioning mode in P-time Petri Net's. So, for the P-time Event Graph, a sufficient condition is given. With this approach and by using the p- and t-semiflows, a performance evaluation is performed.

Journal ArticleDOI
TL;DR: It is proved that the decorated processes of a net can be axiomatized as the arrows of a symmetric monoidal category which, therefore, provides the aforesaid unification.


01 Jan 1996
TL;DR: A polynomial algorithm was given by the authors and Bernardinello for synthesizing pure weighted Petri nets from finite labeled transition systems, and the categorical correspondences between transition systems or step transition systems and nets are re-examined and simplified to Galois connections.
Abstract: A polynomial algorithm was given by the authors and Bernardinello for synthesizing pure weighted Petri nets from finite labeled transition systems. The limitation to pure nets, serious in practice e.g. for modelling waiting loops in communication protocols, may be removed by a minor adaptation of the algorithm, working for general Petri nets fired sequentially. The rule of sequential firing reduces also the expressivity of Petri nets, since it forces a concurrent interpretation on every diamond. This limitation may also be removed by leaving sequential transition systems and lifting the algorithm to step transition systems, which amounts to extract the effective contents of the coreflection between Petri step transition sytems and general Petri nets established by Mukund. By the way, the categorical correspondences between transition systems or step transition systems and nets are re-examined and simplified to Galois connections in the usual setting of ordered sets.

Journal ArticleDOI
01 Apr 1996
TL;DR: An approach to deriving performance and throughput measures of assembly on the basis of critical path analysis of the Petri net representation of plans is presented.
Abstract: This paper uses Petri nets as a representation and analysis framework for automated assembly. It shows how the hierarchical nature of assembly is captured by Petri nets in representing assembly plans and lower level control plans. The tasks in a control plan correspond to assembly robot operations and can be viewed as a lower level representation of tasks at the assembly plan level. Petri nets provide a single unified framework for representing the hierarchical nature of assembly. This paper presents an approach to deriving performance and throughput measures of assembly on the basis of critical path analysis of the Petri net representation of plans.

Journal ArticleDOI
TL;DR: The use of categorical relationships between models for concurrency, allowing the translation of concepts and properties from one model to another, is illustrated by transferring to Petri nets a general concept of bisimulation.

Journal ArticleDOI
TL;DR: This tutorial paper surveys some of the existing techniques for modelling, analysis and synthesis of asynchronous control circuits based on the use of Petri nets, and presents three different approaches to verification of net-based circuits, and shows their relative strengths and weaknesses.

Proceedings ArticleDOI
18 Nov 1996
TL;DR: Petri net concepts are extended to deal with Petri net controllers, by including actuators and sensors as formal structures within the PetriNet controller.
Abstract: As automated manufacturing systems become more complex, the need for an effective design tool to produce both high level discrete event control system (DECS) and low level implementation, becomes increasingly more important. Petri nets represent the most effective method for both the design and implementation of DECSs. The conversion of such Petri nets into real-time applications has recently been greatly simplified through the advent of the token-passing logic (TPL) methodology. The technique has been developed for normal Petri nets, P-timed Petri nets, T-timed Petri nets and coloured Petri nets. In this paper the Petri net concepts are extended to deal with Petri net controllers, by including actuators and sensors as formal structures within the Petri net controller. The conversion of such a Petri net controller into ladder logic diagrams is also demonstrated by considering the control of a component sorting manufacturing system.

Journal ArticleDOI
22 Apr 1996
TL;DR: An extension of high-level Petri nets, namely nested relation/transition nets (NR/T-nets), is described and two evolutionary development strategies are introduced: incremental construction by iteratively evaluating, refining, formalizing and integrating net fragments and adaptation of application-specific reference process and object models.
Abstract: An extension of high-level Petri nets, namely nested relation/transition nets (NR/T-nets), is described. NR/T-nets allow to model distributed processes and related complex structured objects in business applications. The paper focuses on the development of complex NR/T-net models. Due to their complexity high-level Petri net models are usually not developed in one single step. Therefore, two evolutionary development strategies are introduced: on the one hand incremental construction by iteratively evaluating, refining, formalizing and integrating net fragments, on the other hand adaptation of application-specific reference process and object models.

Journal ArticleDOI
TL;DR: This paper focuses on the applicability of fuzzy Petri net approaches in the field of Discrete Events Dynamic Systems and the elements that are fuzzyfied in Petri nets.

Journal Article
TL;DR: In this paper, a new brain-like model called Learning Petri Network (LPN) is introduced, which has the capability of functions distribution and learning, which can be used in the same way as a neural network to model and control dynamic systems.
Abstract: According to recent knowledge of brain science it is suggested that there exists functions distribution, which means that specific parts exist in the brain for realizing specific functions. This paper introduces a new brain-like model called Learning Petri Network (LPN) that has the capability of functions distribution and learning. The idea is to use Petri net to realize the functions distribution and to incorporate the learning and representing ability of neural network into the Petri net. The obtained LPN can be used in the same way as a neural network to model and control dynamic systems, while it is distinctive to a neural network in that it has the capability of functions distribution. An application of the LPN to nonlinear crane control systems is discussed. It is shown via numerical simulations that the proposed LPN controller has superior performance to the commonly-used neural network one.

Book ChapterDOI
24 Jun 1996
TL;DR: An animation utility was developed which made it possible to perform user-friendly CP-net simulations and occurrence graphs were used for debugging the CP-nets, reducing the amount of errors in the final implementation.
Abstract: In this paper, we present an industrial use of Coloured Petri Nets (CP-nets) in designing a security system An animation utility was developed which made it possible to perform user-friendly CP-net simulations Furthermore, occurrence graphs (also known as reachability graphs and state spaces) were used for debugging the CP-net In this way, a series of errors in the model were found and corrected The CP-net design is used as a specification of the implementation of the security system Therefore, finding errors by means of simulations and occurrence graph analysis reduces the amount of errors in the final implementation — making the software quality higher, which is the goal of the project

Proceedings ArticleDOI
01 Feb 1996
TL;DR: A definition of well-defined SPNs is proposed, which takes into account whether the basic underlying stochastic process or the derived reward processes are determined and a state-space-based algorithm to determine whether a given SPN is well- defined is provided.
Abstract: Formalism based on stochastic Petri nets (SPNs) can employ structural analysis to ensure that the underlying stochastic process is fully determined. The focus is on the detection of conflicts and confusions at the net level, but this might require to overspecify a given SPN model. The problem becomes even more critical when reward processes of interest derived from the basic underlying process are considered. Typical examples are state-dependent impulse reward measures. We propose a definition of well-defined SPNs, which takes into account whether the basic underlying stochastic process or the derived reward processes are determined. A state-space-based algorithm to determine whether a given SPN is well-defined is provided.

Book ChapterDOI
01 Sep 1996
TL;DR: Petri nets are a family of formalisms which can be used for the modelling, analysis, implementation and control of production systems, with the benefit of improving the communication between stages of the life cycle.
Abstract: Modern production systems pose a diversity of problems all along their life cycle which are often treated with particular independent formalisms and techniques. Production systems can be viewed as discrete event, continuous, or hybrid systems. Petri nets are a family of formalisms which can be used for the modelling, analysis, implementation and control of these systems, with the benefit of improving the communication between stages of the life cycle.

Book ChapterDOI
01 Sep 1996
TL;DR: Issues that arise when process algebras and Petri nets are linked are discussed, in particular, operators, compositional ity, recursion, refinement and equivalences, and how Petri net methods can be applied to the verification of concurrent algorithms.
Abstract: This paper discusses issues that arise when process algebras and Petri nets are linked; in particular, operators, compositional ity, recursion, refinement and equivalences. It uses the box algebra in order to show how Petri nets can be manipulated algebraically. Also, the paper shows how other process algebras such as CCS, COSY and CSP can be treated in the same way, how Petri net semantics of concurrent programming languages can be given, and how Petri net methods can be applied to the verification of concurrent algorithms.

Journal ArticleDOI
TL;DR: The box calculus is a process algebra with a simple Petri net semantics that provides for the concise translation of parallel programs and for the combination of verification techniques from process algebra and Petri nets.

Book
01 Aug 1996
TL;DR: Background Petri nets and task planning and/or net representation for robotic task sequence planning task decomposition and analysis of robotic assembly task plans using petri nets representation andAnalysis of uncertainty using fuzzy Petri net sensor-based error recovery for task sequence plans using fuzzyPetri nets summary.
Abstract: Background Petri nets and task planning and/or net representation for robotic task sequence planning task decomposition and analysis of robotic assembly task plans using Petri nets representation and analysis of uncertainty using fuzzy Petri nets task sequence planning using fuzzy Petri nets sensor-based error recovery for task sequence plans using fuzzy Petri nets summary.

Journal ArticleDOI
TL;DR: It is shown that positive properties of a net such as liveness and the existence of home states do also hold for the net with static priorities, if a simple condition is imposed on the priority relation.
Abstract: Priority specifications offer a convenient description technique to resolve conflicts in favour of particular actions. Apart from being employed for the specification of the functional behaviour of a system, priorities have also become important in the field of performance analysis using stochastic Petri nets. Here they are implicitly given due to the separation of transitions into immediate and timed. In the performance analysis of such stochastic Petri nets specific properties, like liveness and existence of home states, are of major interest, because they ensure the applicability of a Markovian based analysis. Since several efficient analysis techniques have been developed for Petri nets without priorities, our interest is in using these techniques also for the priority case. This paper shows that positive properties of a net such as liveness and the existence of home states do also hold for the net with static priorities, if a simple condition is imposed on the priority relation.

Journal ArticleDOI
01 Feb 1996
TL;DR: H hierarchical time-extended Petri nets (H-EPNs), an extended Petri net based modeling and analysis tool, are used to derive the coordination level model of hierarchically decomposable systems, viewed from a three-level hierarchical structure of organization, coordination and execution of tasks.
Abstract: In this paper, hierarchical time-extended Petri nets (H-EPNs), an extended Petri net based modeling and analysis tool, are used to derive the coordination level model of hierarchically decomposable systems, viewed from a three-level hierarchical structure of organization, coordination and execution of tasks. A two-layer (vertical) coordination level framework, consisting of the dispatcher/analyzer and the H-EPN controller is presented. A detailed two sub-level (horizontal) H-EPN controller model is derived to model system operations (including system soft failures). Error classification based on the interaction between the various system coordinators is derived from the H-EPN model. The H-EPN approach preserves multi-resolutional system details as well as effective communication flows between the various subsystems. A simple example illustrates the proposed approach. The important H-EPN properties of boundedness, safeness and reversibility are verified.

Journal ArticleDOI
TL;DR: The design of a real-time scheduler for cotrolling flexible production cells using an extension of Petri nets and a distributed discrete-event control system, which is built up of three main structures, the coordination system, and the local and complex controllers for solving conflicts.