Showing papers on "Process architecture published in 1989"
01 Apr 1989
TL;DR: The author proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis, and one section is devoted to marked graphs, the concurrent system model most amenable to analysis.
Abstract: Starts with a brief review of the history and the application areas considered in the literature. The author then proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis. In particular, one section is devoted to marked graphs, the concurrent system model most amenable to analysis. Introductory discussions on stochastic nets with their application to performance modeling, and on high-level nets with their application to logic programming, are provided. Also included are recent results on reachability criteria. Suggestions are provided for further reading on many subject areas of Petri nets. >
10,755 citations
Book•
01 Nov 1989
TL;DR: An extended timed Petri net model is used to model clearly the synchronization involved in these systems, and it is found that the computational complexity involved increases in the same order as they are listed above.
Abstract: Some analysis techniques for real-time asynchronous concurrent systems are presented. In order to model clearly the synchronization involved in these systems, an extended timed Petri net model is used. The system to be studied is first modeled by a Petri net. Based on the Petri net model, a system is classified into either: 1) a consistent system; or 2) an inconsistent system. Most real-world systems fall into the first class which is further subclassified into i) decision-free systems; ii) safe persistent systems; and iii) general systems. Procedures for predicting and verifying the system performance of all three types are presented. It is found that the computational complexity involved increases in the same order as they are listed above.
553 citations
TL;DR: Algorithmic translation of the Ada programs into Petri nets which preserve control-flow and message-flow properties is described, and algorithms are given to analyze the nets to obtain information about static deadlocks that can occur in the original programs.
Abstract: A method is presented for detecting deadlocks in Ada tasking programs using structural; and dynamic analysis of Petri nets. Algorithmic translation of the Ada programs into Petri nets which preserve control-flow and message-flow properties is described. Properties of these Petri nets are discussed, and algorithms are given to analyze the nets to obtain information about static deadlocks that can occur in the original programs. Petri net invariants are used by the algorithms to reduce the time and space complexities associated with dynamic Petri net analysis (i.e. reachability graph generation). >
163 citations
Book•
09 Aug 1989
TL;DR: This paper is concerned with representation by finite and strict predicate/transition nets of Petri nets and its applications in programming languages.
Abstract: programming languages.- Connections with language theory.- Representation by finite automata.- Representation by finite and safe Petri nets.- A remark on the representation by finite Petri nets.- Representation by finite and strict predicate/transition nets.
127 citations
05 Sep 1989
TL;DR: A systematic correspondence between Petri nets, linear logic theories, and linear categories is established, which sheds new light on the relationships between linear logic and concurrency, and on how both areas are related to category theory.
Abstract: Linear logic has been recently introduced by Girard as a logic of actions that seems well suited for concurrent computation. In this paper, we establish a systematic correspondence between Petri nets, linear logic theories, and linear categories. Such a correspondence sheds new light on the relationships between linear logic and concurrency, and on how both areas are related to category theory. Categories are here viewed as concurrent systems whose objects are states, and whose morphisms are transitions. This is an instance of the Lambek-Lawvere correspondence between logic and category theory that cannot be expressed within the more restricted framework of the Curry-Howard correspondence.
100 citations
01 Apr 1989
TL;DR: The ability of ER nets to express a variety of behaviors justifies the choice to use them as a kernel formalism of a specification support environment that is currently developing, and it will be possible to define new graphical notations for formal specifications and give them formal semantics in terms of the underlying ER model.
Abstract: Petri nets have been widely used in the past to model vari&s types of concurrent systems, including real-time systems. To do so, a variety of ad-hoc solutions have been proposed in order to allow time to be taken into account in specifications. In this paper, we initially survey these proposals and then we illustrate a new proposal (TEI nets), that unifies and generalizes all pre,vious ones. Next, we discuss how these and possibly other enrichments of the original model can be formally defined. This will be do,ne in terms of a high-level net model, called ER nets. The ability of ER nets to express a variety of behaviors justifies our choice to use them as a kernel formalism of a specification support environment that we are currently developing. In this environment, it will be possible to define new graphical notations for formal specifications and give them formal semantics in terms of the underlying ER model. This allows the specifier to tune the notation used in formal specifications to the particular expressive needs arising while modelling an application and yet base the notation on firm and rigorous grounds.
82 citations
01 Mar 1989
TL;DR: The author proposes an approach to represent assembly by Petri nets and presents an algorithm of automatic robot assembly planning based on the Petri-net model, which is quite straightforward and can be easily and efficiently implemented with simple matrix manipulation.
Abstract: The author proposes an approach to represent assembly by Petri nets and presents an algorithm of automatic robot assembly planning based on the Petri-net model. The Petri-net model of assembly is configured by the goal structures and initial constraints, both in the Petri-net formalism. Due to the Petri-net representation of assembly, the plan generation is quite straightforward and the planning algorithm can be easily and efficiently implemented with simple matrix manipulation. An example of how to plan an assembly by the Petri net model is presented. >
67 citations
TL;DR: A class of Petri nets is introduced, in which timing constraints are represented by the operators of temporal logic, which can describe clearly and compactly causal and temporal relationships between the events of a system, including eventuality and fairness.
Abstract: A class of Petri nets called temporal Petri nets is introduced, in which timing constraints are represented by the operators of temporal logic. Due to the versatility of the temporal logic operations to express temporal assertions, temporal Petri nets can describe clearly and compactly causal and temporal relationships between the events of a system, including eventuality and fairness. The use of temporal Petri nets is illustrated with a nontrivial example of modeling and analysis of a handshake daisy-chain arbiter. >
66 citations
11 Dec 1989
TL;DR: A natural and compact way to incorporate nonexponential distributions into stochastic Petri nets is described, which allows users to directly specify the nonexp exponential transitions at the next level without providing the detailed construction.
Abstract: A natural and compact way to incorporate nonexponential distributions into stochastic Petri nets is described. It allows users to directly specify the nonexponential transitions at the next level without providing the detailed construction; for example, to specify an Erlang distribution, the user only needs to provide the number of stages and the mean of the distribution. The refinement of the transition with a general distribution is performed automatically with a net-independent mechanism. The resulting net is a GSPN that can be solved with standard techniques. The authors also show how to expand conflicting transitions under the race-enabling policy (without the interconnection of places and transitions internal to the expansion of the different transitions), and have identified the different semantics introduced by nonexponential distributions, when a model does or does not use a control place. >
52 citations
11 Dec 1989
TL;DR: A hierarchy of high-level nets, including many-sorted versions of predicate-transition (PrT) nets and algebraic nets, is developed and differences from their single-sorts versions are discussed.
Abstract: Many-sorted high-level nets (MHLNs) combine abstract data types and Petri nets within the same algebraic framework and include inhibitor arcs and place capacities. Many-sorted signatures are used to define inscriptions. MHLNs are defined at two different levels of abstraction. At an abstract level markings and capacities are defined by terms. This is suitable for specifying classes of systems. At the concrete level, a many-sorted algebra satisfying the signature is used for markings and capacities. Both abstract and concrete MHLNs can be given an interpolation in terms of colored Petri nets extended by place capacities and inhibitors, known as P-nets. A hierarchy of high-level nets, including many-sorted versions of predicate-transition (PrT) nets and algebraic nets, is developed and differences from their single-sorted versions are discussed. >
01 Nov 1989
TL;DR: Petri net principles are illustrated for a machining cell being implemented in the Manufacturing Automation Laboratory at Rutgers University and the difference between a Petri Net Controller and a Programmable Logic Controller for the same application is made.
Abstract: This paper discusses the Petri Net approach to real time production control. Petri nets were developed to model concurrent and asynchronous systems. Having modeled a machining cell or a production system as a Petri net, one can analyze the effects of controller behavior on the system before implementing the controller. Petri net principles are illustrated for a machining cell being implemented in the Manufacturing Automation Laboratory at Rutgers University. Observations are made concerning the difference between a Petri Net Controller and a Programmable Logic Controller for the same application.
01 Oct 1989
TL;DR: The double role that stochastic Petri net simulation plays as an aid in the debugging of the correctness of the model and as a vehicle for the evaluation of the efficiency of the system is discussed.
Abstract: Petri nets are a formal modelling tool very well suited to the description of distributed and concurrent systems which exhibit synchronization and contention for shared resources. Adding random temporal specifications to Petri nets, stochastic Petri nets are obtained from which event driven simulators can be automatically constructed. This paper discusses the double role that stochastic Petri net simulation plays as an aid in the debugging of the correctness of the model and as a vehicle for the evaluation of the efficiency of the system. A modelling tool that has been developed for these purposes is illustrated with an emphasis on the modelling environment it provides and on its internal software architecture.
Journal Article•
29 May 1989
TL;DR: In this article, an assumption/commitment style temporal logic for specifying the behaviour of reactive systems is presented, and an automatic proof method for verifying the correctness of an implementation of such a specification in terms of the considered class of Petri-Nets based on modelchecking of MCTL formula is presented.
Abstract: "How does reactive behaviour decompose? What can be done to encourage stepwise refinement of the behavioural aspects of a system? How can one cope with the intricacy, that the behaviour of a complex reactive system presents??" These questions, posed in [HP85] and informally discussed there in the setting of statecharts, are taken up in this paper using a particular class of Petri-Nets as models for open reactive systems. It presents an assumption/commitment style temporal logic [Pn85] for specifying the behaviour of such systems, an automatic proof method for verifying the correctness of an implementation of such a specification in terms of the considered class of Petri-Nets based on modelchecking of MCTL formula (discussed in a companion paper [Jo89]), and presents a proof-method for infering the behaviour of a compound reactive system from the behaviour of its constituents.
TL;DR: The regenerative method for simulation analysis in the stochastic Petri net setting is established and a limit theorem for irreducible marking processes with finite timed marking set is obtained.
Abstract: Stochastic Petri nets with timed and immediate transitions permit representation of concurrency, synchronization, and communication and provide a general framework for discrete event simulation. Formal definition of the marking process of a stochastic Petri net is in terms of a general state space Markov chain that describes the net at successive marking change epochs. We obtain a limit theorem for irreducible marking processes with finite timed marking set. In addition, we provide conditions on the building blocks of a stochastic Petri net under which the marking process is a regenerative process in continuous time with finite cycle length moments. These results establish the regenerative method for simulation analysis in the stochastic Petri net setting
11 Dec 1989
TL;DR: A lumping method that is based on a particular class of colored Petri nets is presented and the authors show on an example that the method can be usefully applied to the performance evaluation of symmetric systems.
Abstract: A lumping method that is based on a particular class of colored Petri nets is presented. The originality of the method is that the states are aggregated a priori, thus avoiding the construction of the whole reachability graph. The authors construct only a graph of symbolic markings whose states are classes of markings and from which the solution can be directly computed. They show on an example that the method can be usefully applied to the performance evaluation of symmetric systems. >
11 Dec 1989
TL;DR: An examination is made of the problem of eliminating vanishing states during the solution of a generalized stochastic Petri net, and the asymptotic complexity of a matrix-based algorithm is shown to grow quadratically with the number of tangible states.
Abstract: A generalized stochastic Petri net can be analyzed by studying the reachability graph of feasible markings. An examination is made of the problem of eliminating vanishing states during the solution of a generalized stochastic Petri net. The asymptotic complexity of a matrix-based algorithm is shown to grow quadratically with the number of tangible states. A simpler graph-based algorithm that executes much more rapidly on typical models is examined. Some alternatives to elimination are discussed. >
25 Sep 1989
TL;DR: The use of the programming language Prolog for both the specification and the interpretation of the Petri net supports rapid prototyping and offers a powerful framework for integrating rule-based diagnosis and error recovery components into the robot control system.
Abstract: An effort is made to show how Petri nets can be applied to control an advanced multirobot system. The action plan for the robot system, i.e. the description of the task the robot has to perform, is obtained by using a special class of condition/event Petri nets. With the aid of a distributed multiprocessor system, the robot system is able to execute net actions in parallel if necessary. The use of the programming language Prolog for both the specification and the interpretation of the Petri net supports rapid prototyping and offers a powerful framework for integrating rule-based diagnosis and error recovery components into the robot control system. >
11 Dec 1989
TL;DR: In this article, a discussion of the computational complexity aspect of the legal firing sequence problem (LFS) and some related problems of Petri nets, each having applications to practical problems are presented.
Abstract: Development of computational tools and techniques dealing with large-scale Petri nets will provide a firm foundation of Petri net theory. A discussion is presented of the computational complexity aspect of the legal firing sequence problem (LFS) and some related problems of Petri nets, each having applications to practical problems. Their NP-completeness and polynomial-time solvability are presented. >
01 Jan 1989
TL;DR: Two kinds of modelling of manufacturing systems by continuous-PN are presented and the first one gives good results when the system is saturated (many parts) and the second one works well even if the system was not saturated.
Abstract: Continuous Petri Nets (continuous-PN) have been introduced to avoid the explosion of the number of reachable states in a classical Petri Net, when this net contains a great number of tokens. This is the case of production systems, particularly a flexible manufacturing system. In a continuous-PN, the marking of a place is represented by a real number and with each transition is associated a maximum firing speed. Two kinds of modelling of manufacturing systems by continuous-PN are presented in this paper. The first one gives good results when the system is saturated (many parts). The second one works well even if the system is not saturated.
05 Jun 1989
TL;DR: Analytical models are presented that use Petri nets for fault-tolerant schemes used in distributed systems that include rollback recovery with checkpointing, recovery blocks, N-version programming, and conversations.
Abstract: Analytical models are presented that use Petri nets for fault-tolerant schemes used in distributed systems. These models are used in the quantitative evaluation and selection of good fault-tolerant schemes for specific system configurations. Several different fault-tolerant schemes that can be modeled using Petri nets are discussed in detail. These schemes include rollback recovery with checkpointing, recovery blocks, N-version programming, and conversations. After a brief review of Petri net models, extension of the Petri net models to incorporate fault-tolerant schemes is considered. A methodology for evaluating a fault-tolerant scheme for a specific system configuration and the steps involved in building a Petri net model of a fault-tolerant system are described. The subnet primitives involved in building these models are identified and an algorithm for building the models automatically is described. Examples illustrating this extended Petri net model are discussed and numerical results are presented to show the applicability of the models. >
23 Apr 1989
TL;DR: Two classes of non-product-form protocol models where the equilibrium probabilities of state may be computed recursively are described and an algorithm is presented for the computer generation of these recursions.
Abstract: Two classes of non-product-form protocol models where the equilibrium probabilities of state may be computed recursively are described. An algorithm is presented for the computer generation of these recursions. The use of the algorithm is described for manufacturing nets, a class of Petri type networks. These are useful for modeling a linear process where one must wait for components to arrive before one can move to the next step of the process. Aside from the manufacturing context, they are useful for modeling certain communication processes such as multihop radio transmission and layered architecture communications. >
11 Dec 1989
TL;DR: By adopting some standards in notation and nomenclature the communication between research groups is enhanced and by completely dropping redundant models or models with minor variations the community will be able to obtain a more focused view for further research.
Abstract: In the past, Petri net modeling was dominated by the evolution of the model in response to the needs of the applications and problems associated with analyzing the model. The result has been a diverse and confused set of models and notations which hinders new research. New applications are appearing that use the Petri net as the model of choice. By adopting some standards in notation and nomenclature the communication between research groups is enhanced. In addition, by completely dropping redundant models or models with minor variations, the community will be able to obtain a more focused view for further research. >
14 Aug 1989
TL;DR: It is shown how temporal Petri nets can be used for formal specification and verification of the alternating bit protocol.
Abstract: Temporal Petri nets are Petri nets in which certain restrictions on the firings of transitions are represented by formulas containing temporal operators. It is shown how temporal Petri nets can be used for formal specification and verification of the alternating bit protocol. The temporal Petri net which models the protocol is analyzed formally using the existing theory of omega -regular expressions and Buchi-automata. >
26 Feb 1989
TL;DR: A survey on the activities of the authors in recent years is given in order to contribute to theory, development of methodology and tools of this topic.
Abstract: To specify functional requirements of large-scale systems we apply some sort of hierarchically represented Petri nets. Here will be given a survey on our activities in recent years in order to contribute to theory, development of methodology and tools of this topic. A continuation on the development of methodology and tools can be found in [Ditt 89].
TL;DR: One of the most flexible of manufacturing line structures is discussed, the Robot Lattice Structure, which is analysed using a new form of timed Petri-nets, termed Binary Timed Petri Nets.
26 Feb 1989
TL;DR: This paper describes an editor, which supports the hierarchical description of channel-agency nets and a simulator for hierarchically represented condition-event nets, and the requirements to tools to support this methodology.
Abstract: We want to apply Petrinet descriptions in different variations to the modelling of functional requirements and designs of complex systems. Therefore in this paper we suggest a methodology how to do that. Then we scetch the requirements to tools to support this methodology. The main part describes an editor, which supports the hierarchical description of channel-agency nets and a simulator for hierarchically represented condition-event nets.
25 Sep 1989
TL;DR: A quantitative methodology is presented for identifying and evaluating the shortfalls and overlaps between the desired functionality of a distributed intelligence system, as characterized by the requirements and the functions of a proposed or implemented system.
Abstract: A quantitative methodology is presented for identifying and evaluating the shortfalls and overlaps between the desired functionality of a distributed intelligence system, as characterized by the requirements and the functionality of a proposed or implemented system. The approach is based on developing compatible Petri net representations of the requirements and of the system architecture which form the basis for the comparison of the desired and actual functionalities. By using the theory of Petri net invariants, the functionalities in both representations are obtained. They can then be compared to determine shortfalls and overlaps. The methodology is applied to a distributed intelligence system that models a distributed command center. >
TL;DR: A simplified transition identification method is proposed and it is shown that the correspondent Petri net graph is simpler than the authors', but the communication state change table is the same.
Abstract: In the conversation design procedure, the definition of the state of the system is one of the most important aspects The question is how to identify transitions in Occam programs in order to express them as Petri nets In the paper, a simplified transition identification method is proposed Using the robot arm control program of AM Tyrrell and DJ Holding it is shown that the correspondent Petri net graph is simpler than theirs, but the communication state change table is the same It is also shown that these two methods are equivalent >