Showing papers on "Petri net published in 2006"
Proceedings Article•
01 Jan 2006
TL;DR: DecSerFlow is proposed as a Declarative Service Flow Language that can be used to specify, enact, and monitor service flows, and is extendible (i.e., constructs can be added without changing the engine or semantical basis) and used to enforce or to check the conformance of service flows.
Abstract: The need for process support in the context of web services
has triggered the development of many languages, systems, and standards.
Industry has been developing software solutions and proposing
standards such as BPEL, while researchers have been advocating the
use of formal methods such as Petri nets and pi-calculus. The languages
developed for service flows, i.e., process specification languages for web
services, have adopted many concepts from classical workflow management
systems. As a result, these languages are rather procedural and
this does not fit well with the autonomous nature of services. Therefore,
we propose DecSerFlow as a Declarative Service Flow Language. DecSerFlow
can be used to specify, enact, and monitor service flows. The
language is extendible (i.e., constructs can be added without changing
the engine or semantical basis) and can be used to enforce or to check the
conformance of service flows. Although the language has an appealing
graphical representation, it is grounded in temporal logic.
346 citations
TL;DR: This paper develops a two-stage approach to synthesizing liveness-enforcing supervisors for flexible manufacturing systems (FMS) that can be modeled by a class of Petri nets that is more efficient and structurally simpler than all the known existing methods.
Abstract: This paper develops a two-stage approach to synthesizing liveness-enforcing supervisors for flexible manufacturing systems (FMS) that can be modeled by a class of Petri nets. First, we find siphons that need to be controlled using a mixed integer programming (MIP) method. This way avoids complete siphon enumeration that is more time-consuming for a sizable plant model than the MIP method. Monitors are added for only those siphons that require them. Second, we rearrange the output arcs of the monitors on condition that liveness is still preserved. The liveness is verified by an MIP-based deadlock detection method instead of much time-consuming reachability analysis. Experimental studies show that the proposed approach is more efficient than the existing ones and can result in more permissive and structurally simpler liveness-enforcing supervisors than all the known existing methods. This paper makes the application of siphon-based deadlock control methods to industrial-size FMS possible
221 citations
12 Aug 2006
TL;DR: It is shown that satisfiability for the two-variable first-order logic FO2(~,<,+1) is decidable over finite and over infinite data words, where ~ is a binary predicate testing the data value equality and +1,< are the usual successor and order predicates.
Abstract: In a data word each position carries a label from a finite alphabet and a data value from some infinite domain. These models have been already considered in the realm of semistructured data, timed automata and extended temporal logics. It is shown that satisfiability for the two-variable first-order logic FO^2(~,\le,+1) is decidable over finite and over infinite data words, where i« is a binary predicate testing the data value equality and +1,\le are the usual successor and order predicates. The complexity of the problem is at least as hard as Petri net reachability. Several extensions of the logic are considered, some remain decidable while some are undecidable.
220 citations
TL;DR: Improvements are presented using the Petri net reduction approach to simplify very large PetriNet models so as to alleviate computation effort and simplifying the invariant-based control method.
Abstract: Our previous work presented a Petri net-based iterative synthesis policy for deadlock prevention in flexible manufacturing systems (FMS). Given the Petri net model of an FMS prone to deadlock, it aims to synthesize a live controlled Petri net. Its use for FMS control guarantees its deadlock-free operation and high performance in terms of resource utilization and system throughput. At each iteration, a first-met bad marking is singled out from the reachability graph of the Petri net. A well-established invariant-based control method is used to prevent it from being reached. This process is carried out until the net model becomes live. The method proposed is generally applicable, easy to use, effective, and straightforward, although its off-line computation is of exponential complexity. This paper presents two improvements: (a) using the Petri net reduction approach to simplify very large Petri net models so as to alleviate computation effort; and (2) simplifying the invariant-based control method. A number...
206 citations
TL;DR: The paper demonstrates how Petri net analysis techniques can promote a deeper understanding of signal transduction pathways and introduces the new notion of feasible t-invariants, which represent minimal self-contained subnets being active under a given input situation.
Abstract: Signal transduction pathways are usually modelled using classical quantitative methods, which are based on ordinary differential equations (ODEs). However, some difficulties are inherent in this approach. On the one hand, the kinetic parameters involved are often unknown and have to be estimated. With increasing size and complexity of signal transduction pathways, the estimation of missing kinetic data is not possible. On the other hand, ODEs based models do not support any explicit insights into possible (signal-) flows within the network. Moreover, a huge amount of qualitative data is available due to high-throughput techniques. In order to get information on the systems behaviour, qualitative analysis techniques have been developed. Applications of the known qualitative analysis methods concern mainly metabolic networks. Petri net theory provides a variety of established analysis techniques, which are also applicable to signal transduction models. In this context special properties have to be considered and new dedicated techniques have to be designed. We apply Petri net theory to model and analyse signal transduction pathways first qualitatively before continuing with quantitative analyses. This paper demonstrates how to build systematically a discrete model, which reflects provably the qualitative biological behaviour without any knowledge of kinetic parameters. The mating pheromone response pathway in Saccharomyces cerevisiae serves as case study. We propose an approach for model validation of signal transduction pathways based on the network structure only. For this purpose, we introduce the new notion of feasible t-invariants, which represent minimal self-contained subnets being active under a given input situation. Each of these subnets stands for a signal flow in the system. We define maximal common transition sets (MCT-sets), which can be used for t-invariant examination and net decomposition into smallest biologically meaningful functional units. The paper demonstrates how Petri net analysis techniques can promote a deeper understanding of signal transduction pathways. The new concepts of feasible t-invariants and MCT-sets have been proven to be useful for model validation and the interpretation of the biological system behaviour. Whereas MCT-sets provide a decomposition of the net into disjunctive subnets, feasible t-invariants describe subnets, which generally overlap. This work contributes to qualitative modelling and to the analysis of large biological networks by their fully automatic decomposition into biologically meaningful modules.
203 citations
TL;DR: A novel case study of a realistic distributed component-based system is presented, showing how queueing Petri net models can be exploited as a powerful performance prediction tool in the software engineering process.
Abstract: Performance models are used increasingly throughout the phases of the software engineering lifecycle of distributed component-based systems However, as systems grow in size and complexity, building models that accurately capture the different aspects of their behavior becomes a more and more challenging task In this paper, we present a novel case study of a realistic distributed component-based system, showing how queueing Petri net models can be exploited as a powerful performance prediction tool in the software engineering process A detailed system model is built in a step-by-step fashion, validated, and then used to evaluate the system performance and scalability Along with the case study, a practical performance modeling methodology is presented which helps to construct models that accurately reflect the system performance and scalability characteristics Taking advantage of the modeling power and expressiveness of queueing Petri nets, our approach makes it possible to model the system at a higher degree of accuracy, providing a number of important benefits
195 citations
05 Sep 2006
TL;DR: This paper proposes a completely new way of comparing process models that is able to avoid the two problems: directly comparing two models and compared with respect to some typical behavior.
Abstract: In various application domains there is a desire to compare process models, e.g., to relate an organization-specific process model to a reference model, to find a web service matching some desired service description, or to compare some normative process model with a process model discovered using process mining techniques. Although many researchers have worked on different notions of equivalence (e.g., trace equivalence, bisimulation, branching bisimulation, etc.), most of the existing notions are not very useful in this context. First of all, most equivalence notions result in a binary answer (i.e., two processes are equivalent or not). This is not very helpful, because, in real-life applications, one needs to differentiate between slightly different models and completely different models. Second, not all parts of a process model are equally important. There may be parts of the process model that are rarely activated while other parts are executed for most process instances. Clearly, these should be considered differently. To address these problems, this paper proposes a completely new way of comparing process models. Rather than directly comparing two models, the process models are compared with respect to some typical behavior. This way we are able to avoid the two problems. Although the results are presented in the context of Petri nets, the approach can be applied to any process modeling language with executable semantics.
194 citations
01 Nov 2006
TL;DR: In this correspondence, elementary siphons of Petri nets are redefined and the significance of this improvement is shown.
Abstract: The concept of elementary siphons of Petri nets is first proposed in our previous work. However, their definitions can cause confusion when there exist weakly independent siphons in a net. In this correspondence, we redefine elementary siphons and show the significance of this improvement
152 citations
Book•
09 Jun 2006
TL;DR: This book provides a nice presentation of supervisory control of discrete event systems using a Petri net model in a comprehensive manner and would be very useful to researchers in the field ofsupervisory control.
Abstract: Preface.- Symbols.- Introduction.- An Introduction to Petri Nets.- The Supervision of Petri Nets.- Enforcing General Specifications.- Decentralized Supervision of Petri Nets.-Deadlock and Liveness Properties of Petri Nets.- Liveness Enforcement in Petri Nets: A Structural Approach. Part I.- Liveness Enforcement in Petri Nets: A Structural Approach. Part II.- DES Control of Concurrent Hybrid Systems.- Hybrid System Level Control.-References.- Index
137 citations
TL;DR: The new feature of the tool R omeo that implements the translation of TPNs in the U ppaal input format is described and the result of the method is compared to state-of-the-art tool for analyzing TPN's.
135 citations
05 Sep 2006
TL;DR: This paper presents a technology chain that starts out with a BPEL process and transforms it into a Petri net model and decides controllability of the process and compute its operating guideline.
Abstract: This paper addresses the problem of analyzing the interaction between BPEL processes. We present a technology chain that starts out with a BPEL process and transforms it into a Petri net model. On the model we decide controllability of the process (the existence of a partner process, such that both can interact properly) and compute its operating guideline (a characterization of all properly interacting partner processes). A case study demonstrates the value of this technology chain.
11 Sep 2006
TL;DR: Beside the usual graphic editing and simulation facilities, the software tool Tina may build a number of state space abstractions for Petri nets or Time Petrinets, preserving certain classes of properties.
Abstract: Beside the usual graphic editing and simulation facilities, the software tool Tina may build a number of state space abstractions for Petri nets or Time Petri nets, preserving certain classes of properties. For Petri nets, these abstractions help preventing combinatorial explosion and rely on so-called partial order techniques such as covering steps and/or persistent sets. For Time Petri nets, that have in general infinite state spaces, they provide finite representation of their behavior, in terms of state class graphs.
Book•
15 Apr 2006
TL;DR: The motivation for this work was the need for Computer Based Verification and the need to integrate UML Statecharts and Temporal Logic Assertions with CTL, CTL+, Z.
Abstract: OUTLINE 1. Motivation 1.1 The Need for Computer Based Verification 1.2 The Desired Process Triangle 1.3 The Need for Integration: UML Statecharts and Formal Specifications 2. Assertion Languages, Applications, and Tools 2.1 Primary Assertion/Specification Languages: Temporal Logic and Statecharts 2.2 Applications: formal methods, run-time monitoring 2.2.1 Classical Formal Methods. 2.2.2 Runtime Monitoring and Verification. 2.2.3 Automatic Test Generation and Execution-based Model Checking. 2.2.4 Run-time Control Flow using Assertions (Exception Handling) 2.3 Writing Temporal Logic Assertions: the Process 2.4 Tools 3. Integration: UML-Statecharts Integrated with Temporal Logic Assertions 3.1 Statechart Specifications 3.2 TLCharts 3.3. Tools 4. Advanced Topics 4.1 Petri Nets for Distributed Systems. 4.2 Other Specification Languages: CTL, CTL+, Z. 4.3 Automata over Infinite Sequences. 4.4. Automata and Semigroups. 4.5 LTL vs. First Order Logic and SQL, LTL vs. Regular Expressions. 4.6 LTL and Statechart Semantics. 4.6 Knowledge Monitoring.
TL;DR: A technique that uses runtime observations about an executing system to construct an architectural view of the system is described and the DiscoSTEP mapping language and its formal definition are introduced.
Abstract: One of the challenging problems for software developers is guaranteeing that a system as built is consistent with its architectural design. In this paper, we describe a technique that uses runtime observations about an executing system to construct an architectural view of the system. In this technique, we develop mappings that exploit regularities in system implementation and architectural style. These mappings describe how low-level system events can be interpreted as more abstract architectural operations and are formally defined using colored Petri nets. In this paper, we describe a system, called DiscoTect, that uses these mappings and we introduce the DiscoSTEP mapping language and its formal definition. Two case studies showing the application of DiscoTect suggest that the tool is practical to apply to legacy systems and can dynamically verify conformance to a preexisting architectural specification
TL;DR: This paper reveals the significance of the SBPI based on a literature survey, applications, and an analysis of problems and supervisory settings that can be addressed using SBPI to programming with semaphores, fault tolerance, and synchronic-distance based designs.
Abstract: The supervision based on place invariants (SBPI) is an efficient technique for the supervisory control of Petri nets. This paper reveals the significance of the SBPI based on a literature survey, applications, and an analysis of problems and supervisory settings that can be addressed using SBPI. Special attention is given to the various settings within which the problem can be formulated. Such settings can be distinguished based on the concurrency type, the type of controllability and observability, and the centralized or decentralized type of supervision. As we show, it is possible to approach the most general settings in a purely structural way, without resorting to reachability analysis. We begin by describing the SBPI problem and the literature methods that address this problem or are related to it. Then, we proceed to show classes of problems that can be reduced to the SBPI problem. In the SBPI, the specification is described as a system of inequalities that the Petri net marking must satisfy at any time. However, as we show, problems involving more general specifications can be approached in the SBPI setting, sometimes under additional assumptions, by performing net and/or specification transformations. Four of the specifications we will consider are logic constraints, language specifications, disjunctions of linear constraints, and liveness. We conclude with a presentation of possible applications of the SBPI approach to programming with semaphores, fault tolerance, and synchronic-distance based designs.
16 Jan 2006
TL;DR: This paper proposes three theorems to detect implicit dependency between tasks and gives their proofs, and the experimental results show that the approach is powerful enough to mine process models with non-free-choice constructs.
Abstract: Process mining aims at extracting information from event logs to capture the business process as it is being executed. In spite of many researchers’ persistent efforts, there are still some challenging problems to be solved. In this paper, we focus on mining non-free-choice constructs, where the process models are represented in Petri nets. In fact, there are totally two kinds of causal dependencies between tasks, i.e., explicit and implicit ones. Implicit dependency is very hard to mine by current mining approaches. Thus we propose three theorems to detect implicit dependency between tasks and give their proofs. The experimental results show that our approach is powerful enough to mine process models with non-free-choice constructs.
26 Jun 2006
TL;DR: It is shown that analysis based on a discrete Petri net model of the system can be used to derive the sets of initial concentrations required by the corresponding continuous ordinary differential equation model, and no other initial concentrations produce meaningful steady states.
Abstract: We report on the results of an investigation into the integration of Petri nets and ordinary differential equations (ODEs) for the modelling and analysis of biochemical networks, and the application of our approach to the model of the influence of the Raf Kinase Inhibitor Protein (RKIP) on the Extracellular signal Regulated Kinase (ERK) signalling pathway. We show that analysis based on a discrete Petri net model of the system can be used to derive the sets of initial concentrations required by the corresponding continuous ordinary differential equation model, and no other initial concentrations produce meaningful steady states. Altogether, this paper represents a tutorial in step-wise modelling and analysis of larger models as well as in structured design of ODEs.
TL;DR: A general theory of Stochastic Hybrid Systems is proposed and branching and Interactign Particle Interpretations of Rare Event Probabilites are studied.
Abstract: Part I: Stochastic Hybrid Processes.- Toward a General Theory of Stochastic Hybrid Systems.- Hybrid Petri Nets with Diffusion that have Into-Mappings with Generalised Stochastic Hybrid Processes.- Part II: Analytical Approaches.- A Stochastic Approximation Method for Reachability Computations.- Critical Ovservability of a Class of Hybrid Systems and Application to Air Traffic Management.- Part III: Complexity and Randomization.- Monte Carlo Optimisation for Conflict Resolution in Air Traffic Control.- Branching and Interactign Particle Interpretations of Rare Event Probabilites.
TL;DR: In this paper, the scheduling problem for a single-armed cluster tool with reentrant wafer flows using Petri nets is examined. And the cycle time for the asymmetric choice Petri net model for a reentrants wafer How can be easily computed by using the equivalent event graph model.
Abstract: A cluster tool for semiconductor manufacturing consists of several single-wafer processing chambers and a wafer-handling robot in a closed environment. The use of cluster tools is extended to reentrant processes such as atomic layer deposition, where a wafer visits a processing chamber more than once. Such a reentrant wafer How complicates scheduling and control of the cluster tool and often causes deadlocks. We examine the scheduling problem for a single-armed cluster tool with various reentrant wafer flows. We develop a convenient method of modeling tool operational behavior with reentrant wafer flows using Petri nets. By examining the net model, we then develop a necessary and sufficient condition for preventing a deadlock. We also show that the cycle time for the asymmetric choice Petri net model for a reentrant wafer How can be easily computed by using the equivalent event graph model. From the results, we systematically develop a mixed integer programming model for determining the optimal tool operation sequence, schedule, and cycle time. We also extend a workload measure for cluster tools with reentrant wafer flows. Finally, we discuss how our results can be used for engineering a cluster tool. We compare two proposed strategies, sharing and dedicating, of operating the parallel processing chambers for identical process steps.
TL;DR: This paper translates several models of concurrency into the model of higher dimensional automata (HDA), which is the most expressive model under investigation, and proposes four different translations of Petri nets corresponding to the four different computational interpretations of nets found in the literature.
TL;DR: The approach is to make unmarked siphons satisfy cs-property when the elementary ones are properly supervised, the advantage of the novel method is that a much smaller number of supervisory monitors and arcs are added and unnecessary iterative processes are avoided.
TL;DR: SimQPN is presented--a simulation tool for QPNs that provides an alternative approach to analyze QPN models, circumventing the state space explosion problem and proposes a methodology for analyzing QPN model analysis by means of discrete event simulation.
16 Oct 2006
TL;DR: This paper proposes a technique for analysis and testing BPEL-based Web service composition using high-level Petri nets and illustrates how these compositions are verified by analyzing the structure of Web service compositions based on BPEL and constructing the corresponding HPN.
Abstract: This paper proposes a technique for analysis and testing BPEL-based web service composition using High-level Petri Nets. To illustrate how these compositions are verified, the relationships between BPEL-based web service composition and High-level Petri Nets is constructed. By analyzing the structure of web service composition based on BPEL, the corresponding HPN is constructed. The dynamism and occurrence are presented in HPN with guard expression with coloured token. After translation, the equivalent HPN of the web service composition based on BPEL can be verified on existing mature tool, and the related researches on HPN, e.g. testing coverage and reduction techniques that have been studied deeply, can be employed in testing of web service composition based on BPEL, optimized test case can be generated based on the HPN translated. An example is provided to illustrate the translation ruled and the automatic verify progress.
06 Mar 2006
TL;DR: This paper presents an effective approach to formally verify SystemC designs into a Petri-Net based representation, which is particularly suitable for models at a high level of abstraction, such as transaction-level.
Abstract: This paper presents an effective approach to formally verify SystemC designs. The approach translates SystemC models into a Petri-Net based representation. The Petri-net model is then used for model checking of properties expressed in a timed formal verification SystemC designs Petri-net model model checking timed temporal logic . The approach is particularly suitable for, but not restricted to, models at a high level of abstraction, such as transaction-level. The efficiency of the approach is illustrated by experiments
TL;DR: The design and prototype implementation of a Grid workflow management system is presented, including a set of description languages required for orchestrating abstract workflows and for mapping them onto real Grid infrastructure, as well as a workflow enactment service that executes loosely coupled Grid jobs on the Grid.
16 Oct 2006
TL;DR: A novel approach to reason about soundness based on so-called causal footprints is presented, which proves that the "vicious circle", that is heavily discussed in EPC literature, is unsound.
Abstract: The correctness of business process models is of paramount importance for the application on an enterprise level. A severe problem is that several languages for business process modelling do not have formal execution semantics which is a prerequisite to check correctness criteria. In this context, soundness defines a minimum correctness criterion that a process model should fulfill. In this paper we present a novel approach to reason about soundness based on so-called causal footprints. A causal footprint represents a set of conditions on the order of activities that holds for every case of a process model. We identify three kinds of error patterns that affect the soundness of a process model, namely the deadlock pattern, the multiple termination pattern, and the trap pattern. We use Eventdriven Process Chains (EPCs) and Petri nets to demonstrate the applicability of our approach for both conceptual as for formal process modelling languages. Furthermore, it can easily be applied to other languages, such as UML activity diagrams or BPEL. Based on the trap pattern, we prove that the .vicious circle., that is heavily discussed in EPC literature, is unsound.
TL;DR: A new T-characteristic vector ζ is proposed to compute strict minimal siphons (SMS) for S3PR (systems of simple sequential processes with resources) in an algebraic fashion and it is discovered that elementary siphons can be constructed from elementary circuits where all places are resources.
Abstract: When designing liveness-enforcing Petri net supervisors, unlike other techniques, Li et al. added control places and arcs to a plant net model for its elementary siphons only, greatly reducing the structural complexity of the controlled system. Their method, however, suffers from the expensive computation of siphons. We propose a new T-characteristic vector ζ to compute strict minimal siphons (SMS) for S3PR (systems of simple sequential processes with resources) in an algebraic fashion. For a special subclass of S3PR, called S4PR (simple S3PR), we discover that elementary siphons can be constructed from elementary circuits where all places are resources. Thus, the set of elementary siphons can be computed without the knowledge of all SMS. We also propose to construct characteristic T-vectors η by building a graph to find dependent siphons without their computations.
TL;DR: This schema allows us to define forward algorithms that decide the coverability problem for several classes of systems for which the Karp and Miller procedure cannot be generalized, and for which no complete forward algorithms were known.
17 Sep 2006
TL;DR: A Petri net based analysis method is proposed that provides a sufficient criterion for the termination problem of model transformations captured by graph transformation systems and is proposed to be a central validation problem of trusted model transformations.
Abstract: Despite the increasing relevance of model transformation techniques in model-driven software development, research is mainly conducted to the specification and the automation of such transformations. However, since the transformations themselves may also contain conceptual flaws, it is essential to formally analyze them prior to executing them on user models. In the current paper, we focus on a central validation problem of trusted model transformations, namely, termination and propose a Petri net based analysis method that provides a sufficient criterion for the termination problem of model transformations captured by graph transformation systems.
21 Jun 2006
TL;DR: This paper focuses on the use of generalized stochastic PNs (GSPNs) to model and analyze attack trees with the ultimate goal of automating the analysis using simulation tools.
Abstract: In recent years, attack trees have been developed to describe processes by which malicious users attempt to exploit or break computer software and/or networks. Attack trees are a way of decomposing, visualizing, and determining the cost or likeliness of attacks. Similarly, Petri nets (PNs) are graphical representations of a system or process used for modeling, formal analysis, and design verification. PNs are easy to build and simulate using a myriad of available tools. There are a number of subclasses of PNs, including colored, timed, stochastic, etc. This paper focuses on the use of generalized stochastic PNs (GSPNs) to model and analyze attack trees with the ultimate goal of automating the analysis using simulation tools. The results of this simulation and analysis can be used to further refine the attack tree or to develop countermeasures