Showing papers on "Petri net published in 1986"
01 Jun 1986
TL;DR: In this paper, a class of Petri nets in which transitions can fire after either a deterministic or a random, exponentially distributed, firing delay is defined, and a solution technique is presented to obtain the steady-state probability distribution over markings, introducing restrictions on the use of deterministic firing delays.
Abstract: A class of Petri nets (DSPN) in which transitions can fire after either a deterministic or a random, exponentially distributed, firing delay is defined, and a solution technique is presented to obtain the steady-state probability distribution over markings, introducing restrictions on the use of deterministic firing delays. An example of application of this modeling technique is presented to demonstrate the impact that the use of a mix of deterministic and exponentially distributed firing delays (instead of all exponentially distributed firing delays) can have on performance and reliability estimates.
377 citations
[...]
TL;DR: Coloured Petri nets (CPN) is a formalism which extends ordinary Petrinets by adding data types and modularity, which means that is possible to make succinct, readable and structured models.
Abstract: This paper describes a Petri net model, called Coloured Petri nets (CP-nets), where information is attached to each token. The information can be inspected and modified when a transition fires. For most applications, this generalization of ordinary Petri nets allows the user to make more manageable descriptions, due to the fact that equal subnets can be folded into each other, yielding a much smaller net. The paper investigates how to analyse Coloured Petri nets. It turns out that place-invariants and reachability trees, two of the most important methods for ordinary Petri nets, can be generalized to apply for Coloured Petri nets.
251 citations
TL;DR: A methodology for the rapid prototyping of process control systems which is based on an original extension to classical Petri nets, and these nets are shown to be translatable into Ada program structures concerning concurrent processes and their synchronizations.
Abstract: A methodology for the rapid prototyping of process control systems which is based on an original extension to classical Petri nets is presented. The proposed nets, called PROT nets, provide a suitable framework to support the following activities: building an operational specification model; evaluation, simulation, and validation of the model; and automatic translation into program structures. PROT nets are shown to be translatable into Ada program structures concerning concurrent processes and their synchronizations. The authors illustrate this translation in detail using, as a working example, the problem of tool handling in a flexible manufacturing system.
219 citations
TL;DR: In this paper, a control program is described with the Petri net-like language named Control-Net (C-net), which improves control software maintainability and flexibility, and an efficient C-net interpretation schema for realtime control is presented and an overhead time evaluation model of the proposed schema is developed.
Abstract: A new type of software system for an industrial sequence controller is proposed. In this system, a control program is described with the Petri net-like language named Control-net (C-net). This language improves control software maintainability and flexibility. An efficient C-net interpretation schema for real-time control is presented and an overhead time evaluation model of the proposed schema is developed. Through the model analysis and measurement of the response time of an interpreter on a microcomputer, it is proved that the interpretation schema satisfies the required response time. Finally, a microcomputer based controller named Station Controller (SCR) in which the presented C-net interpreter was installed is described and several applications of this controller to real systems are illustrated.
198 citations
TL;DR: The signing of a contract - a tree-structured application modelled with petri net building blocks and a logical formalism for the study of the finite behaviour of Petri nets
Abstract: The signing of a contract - a tree-structured application modelled with petri net building blocks.- Checking properties of nets using transformations.- Petri nets and algebraic calculi of processes.- Fair controls and their realization.- Beta processes of C/E systems.- Synchronic distances in C/E systems.- Process periods and system reconstruction.- Guidelines on using net analysis techniques with large specifications.- Application of an extension of petri nets to modelization of control and production processes.- Making nets abstract and structured.- Petri net tools.- Projections of CE-systems.- Synchronic structure.- Safe states in Banker like resource allocation Problems.- Coordination technology and Petri nets.- Pascal semantics by a combination of denotational semantics and high-level petri nets.- On the invariants of coloured Petri Nets.- A logical formalism for the study of the finite behaviour of Petri nets.- Determination of a poset by its co-relation.- Some equivalence notions for concurrent systems. An overview.- Towards a comprehensive office model integrating information and resources.- Non-linear invariants for coloured Petri nets with interdependent tokens application to the proof of parallel programs.- Protocol analysis using Numerical Petri Nets.- Petri nets, morphisms and compositionality.- M-timed Petri nets, priorities, preemptions, and performance evaluation of systems.
174 citations
TL;DR: A new model for parallel computations and parallel computer systems that is based on data flow principles is presented, which can be used to model computer systems including data driven and parallel processors.
Abstract: In this paper, a new model for parallel computations and parallel computer systems that is based on data flow principles is presented. Uninterpreted data flow graphs can be used to model computer systems including data driven and parallel processors. A data flow graph is defined to be a bipartite graph with actors and links as the two vertex classes. Actors can be considered similar to transitions in Petri nets, and links similar to places. The nondeterministic nature of uninterpreted data flow graphs necessitates the derivation of liveness conditions.
142 citations
01 Jun 1986
TL;DR: The theory is confined to a restricted class of Petrinets called safe Petri nets which correspond essentially to systems that have finite state spaces.
Abstract: We give a sketch of the theory of Petri nets. The aspects that we concentrate on are the basic notions of the theory and the interplay between the structure and behaviour of distributed systems as modelled by Petri nets. The theory we present is confined to a restricted class of Petri nets called safe Petri nets which correspond essentially to systems that have finite state spaces.
119 citations
01 Jun 1986
TL;DR: A Petri net semantics for a subset of CCSP, the union of Milner's CCS and Hoare's CSP, based on Plotkin-style transition rules, which differ in the way they model the interplay of the central concepts in CCSP: concurrency, nondeterminism and recursion.
Abstract: We provide a Petri net semantics for a subset of CCSP, the union of Milner's CCS and Hoare's CSP. It assigns to each process term in the subset a labelled, one-safe place/transition net. As opposed to many other approaches to Petri net semantics, our definition is operational as it is based on Plotkin-style transition rules. These rules are inspired by work of Degano, DeNicola and Montanari, but differ in the way they model the interplay of the central concepts in CCSP: concurrency, nondeterminism and recursion. To discuss these differences, we propose criteria for a good Petri net semantics for CCSP.
119 citations
01 Jun 1986
TL;DR: A way of combining algebraic specifications and Petri nets for specifying parallel systems formally, where the data structure of a system is algebraically specified while its behaviour, and especially the synchronization constraints, are specified by a Petri net-like schema.
Abstract: We present a way of combining algebraic specifications and Petri nets for specifying parallel systems formally. The data structure of a system is algebraically specified while its behaviour, and especially the synchronization constraints, are specified by a Petri net-like schema. The semantics of a specification is defined as a class of coloured Petri nets.
87 citations
TL;DR: Two well-known traditional models for asynchronous circuits, namely, the Finite State Machines and Petri Nets, are presented and the reasons for their failure in VLSI applications are discussed.
80 citations
Book•
01 Jan 1986
TL;DR: In this article, the authors present a review of FMS planning models and present a hierarchical structure for production planning and control in FMSs, based on Petri Nets for specification.
Abstract: 1. Introduction. A review of FMS planning models (A.J. van Looveren et al.). The evolution of robotics in manufacturing (J.F. Bard). 2. Materials Handling Systems. Materials handling and logistics: demands for efficiency and flexibility (W. Grosseschallau). Autonomous material handling in computer-integrated manufacturing (C.G. Cassandras). Parts and tools handling systems (A. Kusiak). Robot system hazard assessment using event trees (R.H. Jones et al.). 3. Strategic Planning. The TESPA-concept of FMS (A.M. Huska). Perspectives on flexibility in manufacturing: hardware vs. software (J. Blackburn, R. Millen). Technical advances and competitive position: gaining a strategic edge from automated batch production (C.A. Lengnick-Hall, D.C. King). Manufacturing-marketing strategic interface: the impact of FMSs (G.H.G. McDougall, H.A. Noori). 4. Production and Process Planning. Towards a hierarchical structure for production planning and control in FMSs (A. Villa, S. Rossetto). Production scheduling and materials requirements planning for flexible manufacturing (C. White). Computer-aided technological process planning: methods, systems and application experiences (I. Cser, T. Toth). 5. System Design. Modeling a system of flexible manufacturing cells (Y. Dallery, D.D. Yao). Analysis of an FMS design problem by power approximation (H. Wang). 6. Information and Decision Support Systems. FMSs: an information systems framework (S.I. Ahmad, B. Farah). Decision support requirements for production planning in FMS environments (A. Dutta). 7. Expert Systems. Knowledge based control system for automated production and assembly (D. Ben-Arieh). Applications of decision support and expert systems in FMSs (E. Turban, M. Sepehri). 8. Petri Nets. Petri Nets for specification of FMSs (J. Martinez et al.). 9. FMS Applications. FMS applications in Germany: objectives and constraints (H.J. Warnecke et al.). Author Index.
TL;DR: A generalization of reachability trees is contributed to, which is one of the other important analysis methods known for place/transition nets.
01 Apr 1986
TL;DR: A methodology is presented for constructing models of manufacturing processes for simulation and design of the discrete control logic of discrete parts manufacture and assembly with guaranteed properties based on extensions of previous results in Petri net theory.
Abstract: A methodology is presented for constructing models of manufacturing processes for simulation and design of the discrete control logic. The models represent the discrete event evolution of the system as well as features of the underlying continuous processes. For applications such as discrete parts manufacture and assembly, the process is decomposed into operations with specified precedence relations. For each operation the required resources and associated discrete resource states are identified. Also associated with each resource is a set of resource attributes which are modified by the processes underlying each operation. The structure of the discrete-level control is modeled by modified Petri nets which are synthesized from single resource activity cycles. Construction of the net provides discrete control logic for error recovery loops and other real-time decision structures with guaranteed properties based on extensions of previous results in Petri net theory. The modeling methodology is applied to a two-arm robotic assembly cell example.
07 Apr 1986
TL;DR: Applications of Petri net models in the design of simulators for flexible manufacturing systems (FMSs) and in the verification (by investigating the presence/absence of deadlock) of the logic used to design the hardware/software for controllers used in FMSs are presented.
Abstract: Petri nets have evolved into a powerful tool for analyzing asynchronous concurrent systems. In this paper we review the applications of Petri nets to FMSs. We present applications of Petri net models in the design of simulators for flexible manufacturing systems (FMSs) and in the verification (by investigating the presence/absence of deadlock) of the logic used to design the hardware/software for controllers used in FMSs.
08 Sep 1986
TL;DR: The class of free choice nets, whose structure theory is particularly agreeable, is studied in some detail.
Abstract: Structure theory asks whether a relationship can be found between the behaviour of a marked net and the structure of the underlying unmarked net. From the rich body of structure theoretical results that exists in Petri net theory, this paper selects a few examples which are deemed to be typical. The class of free choice nets, whose structure theory is particularly agreeable, is studied in some detail.
08 Sep 1986
TL;DR: The model presented is based on common techniques of modelling static systems as structured sets of individuals (relational structures) that are ‘dynamised’ by allowing some relations between individuals to be changed by the processes of the modelled system.
Abstract: The paper deals with conceptual, mathematical and practical aspects of developing a net theoretic system model. The model presented is based on common techniques of modelling static systems as structured sets of individuals (relational structures). These structures are ‘dynamised’ by allowing some relations between individuals to be changed by the processes of the modelled system.
TL;DR: Using structural properties of the SPN and recurrence theory for generalized semi-Markov processes, conditions are established which ensure that the marking process of an SPN is a regenerative process and that the expected time between regeneration points is finite.
01 Jun 1986
TL;DR: A computationally feasible procedure for the generation of all invariants satisfying a given homogenous linear Diophantine system Cx=0 is presented, where C is the flow matrix of an associated P/T net.
Abstract: A computationally feasible procedure for the generation of all invariants satisfying a given homogenous linear Diophantine system Cx=0 is presented, where C is the flow matrix of an associated P/T net. The computation will be considered on five levels. In order to generate all invariants the introduction of some new concepts (ℚ-generators, IN-generators) is required. Using geometrical aspects a short description of the new concepts with a new algorithm is shown. The efficiency of our methods is demonstrated by an application.
08 Sep 1986
TL;DR: In this article, the authors define families of formal languages related to classes of P/T-systems and define transition sequences as a way to define the possible finite or infinite occurence sequences of a Petri net to the transitions.
Abstract: Petri nets where multiple arcs are allows and the capacity of the places need not be bounded are here called Place/Transition systems. The restrictions of the possible finite or infinite occurence sequences of a P/T-system to the transitions are called transition sequences and give the basis to define families of formal languages related to classes of P/T-systems.
01 Jun 1986
TL;DR: The aim of this paper is to provide an outlook at this part of the theory of infinitary languages that seems to be essential for understanding the modern theory of concurrent systems.
Abstract: The aim of this paper is to provide an outlook at this part of the theory of infinitary languages that seems to be essential for understanding the modern theory of concurrent systems. In the first part of this paper we discuss an automata-based approach to infinitary languages. In the second part we turn into applying this theory to concurrent systems as considered within the framework of Petri nets.
TL;DR: A distributed microprocessor-based architecture is described and a two-level machine tool synchronization structure is presented, given in terms of Petri nets: a graphical-mathematical technique suitable for representing process parallelism and asynchronism for flexible control of machine tools in a job shop environment.
01 May 1986
TL;DR: An exact analytical technique is used, based on Generalized Timed Petri Nets, to study the performance of shared bus cache consistency protocols for multiprocessors and quantitatively assess the performance gains for each of the four enhancements.
Abstract: We use an exact analytical technique, based on Generalized Timed Petri Nets (GTPNs), to study the performance of shared bus cache consistency protocols for multiprocessors. We develop a general framework within which the key characteristics of the Write-Once protocol and four enhancements that have been combined in various ways in the literature can be identified and evaluated. We then quantitatively assess the performance gains for each of the four enhancements. We consider three levels of data sharing in our workload models. One of the enhancements substantially improves system performance in all cases. Two enhancements are shown to have negligible effect over the range of workloads analyzed. The fourth enhancement shows a small improvement for low levels of sharing, but shows more substantial improvement as sharing is increased, if we assume a “good access pattern”. The effects of two architectural parameters, the blocksize and the main memory cycle time are also considered.
TL;DR: This paper shows how dummy transitions can be incorporated in a timed Petri net to model contingencies in the system such as machine or tool breakdown, quality deterioration, or production volume surge.
08 Sep 1986
TL;DR: In the 1970ies, Place/Transition Systems were certainly the most common and the most extensively studied class of nets.
Abstract: In the 1970ies, Place/Transition Systems were certainly the most common and the most extensively studied class of nets. Often they have just been called Petri Nets.
01 Jun 1986
TL;DR: This thesis describes a method for simulating processes over multiple levels of abstraction and presents a four-level elevator system and a two-level "dining philosophers" simulation to demonstrate the efficacy of process abstraction.
Abstract: This thesis describes a method for simulating processes over multiple levels of abstraction. There has been recent work with respect to data, object, and problem-solving abstraction, however, abstraction in simulation has not been adequately explored. We define a process as a hierarchy of distinct production rule sets that interface to each other so that abstraction levels may be bridged where desired. In this way, the process may be studied at abstraction levels that are appropriate for the specific task:notions of qualitative and quantitative simulation are integrated to form a complete process description. The advantages to such a description are increased control, computational efficiency and selective reporting of simulation results. Within the framework of hierarchical reasoning, we will concentrate on presenting the primary concept of process abstraction.
A Common Lisp implementation of the hierarchical reasoning theory called HIRES is presented. HIRES allows the user to reason in a hierarchical fashion by relating certain facets of the simulation to levels of abstraction specified in terms of actions, objects, reports, and time. The user is free to reason about a process over multiple levels by weaving through the levels either manually or via automatically controlled specifications. Capabilities exist in HIRES to facilitate the creation of graph-based abstraction levels. For instance, the analyst can create continuous system models (CSMP), petri net models, scripts, or generic graph models that define the process model at a given level. We present a four-level elevator system and a two-level "dining philosophers" simulation to demonstrate the efficacy of process abstraction.
TL;DR: The authors address one case in which blocking is present because of critical sections of code; this cannot be treated within the framework of product-form queuing network models, and show how a combination of generalized stochastic petri nets and queuing networks can easily model the situation under consideration.
Abstract: Much work has been done on the modeling of hardware resources; far fewer studies have been conducted on the impact of software systems on the underlying hardware. The authors address one such case in which blocking is present because of critical sections of code; this cannot be treated within the framework of product-form queuing network models. They show how a combination of generalized stochastic petri nets and queuing networks can easily model the situation under consideration. In addition, they show how a simple extension of this model can be applied to studying realistic systems with several domains.
08 Sep 1986
TL;DR: The way Petri Nets are used in production systems will be presented: class of nets, high level nets, net interpretation, the problem of structuration, specification and analysis...
Abstract: Petri Nets and related graphical models are actually being employed in indutry for the design and implementation of production system control. This lecture will present a short overview of this utilization, and the reasons why this tool is more convenient than other models for concurrency will be analysed. Then, the way Petri Nets are used in production systems will be presented: class of nets, high level nets, net interpretation, the problem of structuration, specification and analysis... Finally, some principles about direct implementations will be given.
01 Jun 1986
TL;DR: An object-oriented approach for building distributed systems using ADA as the target language, exploiting its tasking and structuring mechanisms and the possibility of using a knowledge-based user interface promote rapid prototyping and reusability.
Abstract: This paper presents an object-oriented approach for building distributed systems. An example taken from the field of computer integrated manufacturing systems is taken as a guideline. According to this approach a system is built up through three steps: control and synchronization aspects for each class of objects are treated first using PROT nets, which are a high-level extension to Petri nets; then data are introduced specifying the internal states of the objects as well as the messages they send each other; finally the connections between the objects are introduced by means of a data flow diagram between classes. The implementation uses ADA as the target language, exploiting its tasking and structuring mechanisms. The flexibility of the approach and the possibility of using a knowledge-based user interface promote rapid prototyping and reusability.
02 Jul 1986
TL;DR: The present paper describes the automatic synthesis package of the CAMAD system which takes a high level behavioral description as its input and synthesizes it into an implementation structure, which allows potentially asynchronous operation of the designed systems as well as physical distribution of the modules.
Abstract: CAMAD is a high level design tool which helps designers to model, analyze, and design VLSI systems. This design aid system is based on a unified design representation model derived from timed petri nets and consisting of separate but related models of control and data parts. The present paper describes the automatic synthesis package of the CAMAD system which takes a high level behavioral description as its input and synthesizes it into an implementation structure. This implementation structure may then be partitioned into several quasi-independent modules with well-defined interfaces, which allows potentially asynchronous operation of the designed systems as well as physical distribution of the modules.
TL;DR: A method is proposed which uses a Petri net model to formally identify both the state and the state reachability tree of a distributed system, which are used to define systematically the boundaries of a conversation.
Abstract: The problems of error detection and recovery are examined in a number of concurrent processes expressed as a set of communicating sequential processes (CSP). A method is proposed which uses a Petri net model to formally identify both the state and the state reachability tree of a distributed system. These are used to define systematically the boundaries of a conversation, including the recovery and test lines which are essential parts of the fault-tolerant mechanism. The techniques are implemented using the OCCAM programming language, which is derived from CSP. The application of this method is shown by a control example.