Petri网的工作流模型建模研究

实现工作流技术的关键环节在于工作流的概念模型,而其中的过程建模又是构建工作流管理系统的基础,因此,对建立工作流模型的研究和应用比较多。近几年,随着业务流程建模、工作流概念的出现以及Petri网技术的发展,Petri网也被用于工作流模型的建立。该文在介绍工作流模型和Petri网基本概念的基础上,介绍工作流的四种基本流程结构,并以工作流的四种基本流程结构为出发点,给出了如何把它们映射成符合工作流网定义的模型的一种方法。     

需求信息管理的Petri网工作流模型

针对目前国内软件企业中需求信息管理存在的业务流程问题,提出合理的工作流建模方案。利用Petri网建模技术建立流程实例模型,再建立完整的工作流模型。按照Petri网的数学特性对结果模型进行的正确性分析和验证表明该模型具有良好的数学特性。基于Petri网的工作流建模方法能够为需求信息管理提供合理的解决方案。摘要:     

需求信息管理的Petri网工作流模型

针对目前国内软件企业中需求信息管理存在的业务流程问题．提出合理的工作流建模方案。利用Petri网建模技术建立流程实例模型,再建立完整的工作流模型。按照Petri网的数学特性对结果模型进行的正确性分析和验证表明该模型具有良好的数学特性。基于Petri网的工作流建模方法能够为需求信息管理提供合理的解决方案。     

基于Petri网的工作流过程建模

业务过程建模是整个工作流管理系统的基础,选择一种高效的建模技术对复杂多变的实际业务流程进行形式化表示对构建一个灵活的工作流管理系统起着至关重要的作用。本文利用了Petri网技术给业务过程建模,构造了一个灵活可分析的过程模型：首先介绍了相关的基于Petri网的工作流建模技术,接着描述了Petri网到工作流过程模型执行的映 射,然后给出了一个具体的基于Petri网建模方式的实例,最后利用随机Petri网和概率论的一些知识对该模型进行了时间性能分析。     

基于Petri网的工作流技术在MIS中的应用

工作流技术是计算机领域中的一门新兴技术,工作流技术支持的信息系统具有良好的适应性和灵活性。文中简要地介绍了WFMIS和基于Petri网的工作流模型,结合具体的实例,分析了WFMIS开发中模型的建立及流程的管理和监控,实现了工作流管理系统的Petri网建模。     

基于Petri网的工作流技术在MIS中的应用

工作流技术是计算机领域中的一门新兴技术,工作流技术支持的信息系统具有良好的适应性和灵活性.文中简要地介绍了WFMIS和基于Petri 网的工作流模型,结合具体的实例,分析了WFMIS开发中模型的建立及流程的管理和监控,实现了工作流管理系统的Petri 网建模.     

基于面向对象Petri网的工作流建模及性能分析

工作流技术作为一种过程建模和过程管理的核心技术,在计算机应用领域获得了迅速的发展。介绍了工作流技术;提出了将面向对象建模技术融入Petri网模型所形成的面向对象Petri网,并讨论了建立基于面向对象Petri网的工作流模型的步骤;运用面向对象Petri网建立了某制造企业的产品方案处理流程的工作流模型,并运用性能等价公式对工作流模型的性能进行了分析。     

着色Petri网在工作流建模中的应用

工作流建模是工作流管理系统进行工作流管理所必不可少的一个环节。而Petri网以其严格的数学基础、成熟的分析方法和工具而日益得到广泛的应用。本文介绍了着色Petri网在工作流建模中的作用，然后对一个具体的业务流程分别用经典Petri网和着色Petri网建立了过程模型并进行了比较。     

基于Petri网的工作流模型

Petri网是一种很有效的模型描述语言，不仅能描述系统的结构特性，同时还能描述其动态特性，尤其适用于描述含有并行成分的系统，而工作流技术作为实现企业过程集成的有效手段，广泛用于各种场合。在简要介绍了Petri网和工作流基本知识的基础上，指出了基于Petri网的工作流模型的优点，讨论了将工作流模型转化为Petri网模型的基本原则，并且提出了一种扩展的Petri网模型作为一种工作流建模的工具，最后对基于Petri网的工作流模型进行了总结。     

基于面向对象Petri网的工作流建模及性能分析

工作流技术作为一种过程建模和过程管理的核心技术，在计算机应用领域获得了迅速的发展。介绍了工作流技术；提出了将面向对象建模技术融入Petri网模型所形成的面向对象Petri网，并讨论了建立基于面向对象Petri网的工作流模型的步骤；运用面向对象Petri网建立了某制造企业的产品方案处理流程的工作流模型，并运用性能等价公式对工作流模型的性能进行了分析。     

Mapping PUNITY to UniNet

To solve the problems of the interleaving assumption and the single resource in PUNITY(Petri net and UNITY) and Petri net respectively,this paper proposes a set of mapping rules from PUNITY to uniNet.Based on these rules,problems of one field can be transformed to problems of the other field and powerful tools of Petri net and UNITY can be used.The paper gives a sketch of the mapping rules and applies the rules to an example.Meanwhile ,the mapping rules can help computer to translate PUNITY to UniNet easily.     

Verifying soundness of business processes: A decision process Petri nets approach

This paper presents a trajectory-tracking approach for verifying soundness of workflow/Petri nets represented by a decision-process Petri net. Well-formed business processes correspond to sound workflow nets. The advantage of this approach is its ability to represent the dynamic behavior of the business process. We show that the problem of finding an optimum trajectory for validation of well-formed business processes is solvable. To prove our statement we use the Lyapunov stability theory to tackle the soundness verification problem for decision-process Petri nets. As a result, applying Lyapunov theory, the well-formed verification (soundness) property is solved showing that the workflow net representation using decision process Petri nets is uniformly practically stable. It is important to note that in a complexity-theoretic sense checking the soundness property is computationally tractable, we calculate the computational complexity for solving the problem. We show the connection between workflow nets and partially ordered decision-process Petri net used for business process representation and analysis. Our computational experiment of supply chains demonstrate the viability of the modeling and solution approaches for solving computer science problems.     

一个基于Petri网的Web服务组合模型

作为企业应用集成的重要手段，Web服务组合需要建立可靠的表达和分析方法。因此，基于Petri网技术定义一个Web服务组合模型，将组合Web服务的要索映射到Petri网结构。利用Petri网提供的分析技术，辅助复杂业务流程的建模，并分析验证其正确性和性能。     

基于Petri网化简技术的工作流模型正确性研究

为了更有效地对工作流模型进行分析验证，提出了一种基于Petri网化简技术的工作流模型正确性验证方法。在对各种工作流模型验证技术深入研究的基础上，通过对非自由选择网结构活性和有界性的分析，给出了针对Petri网中非自由选择部分的分析方法。在保持活性和有界性的前提下，给出了将活的且有界的非自由选择部分转化为自由选择部分的转化方法，从而将非自由选择的Petri网验证问题转化为自由选择Petri网的验证问题。通过一个例子说明了如何使用该文提出的方法来验证模型的正确性。     

Collaborative composition of processes in holonic manufacturing systems

Although it provides a flexible architecture to deal with changes and uncertainties, holonic manufacturing systems (HMS) also pose challenges in design and implementation. A challenge is to design a problem solving environment to guide the holons in HMS such that the decisions made by the individual holons as a whole collaboratively compose the production processes for the tasks. The objective of this paper is to propose a problem solving environment for the composition of minimal cost processes in HMS. Given a specific product type and due date, the problem is to dynamically compose a complete process in HMS to process the product by the due date. To achieve the objective, we combine multi-agent systems technology with Petri nets in this paper. We first propose architecture and a two-layer contract net protocol to describe the negotiation between order holons, product holons and resource holons in HMS. To determine whether it is feasible for a set product holons and resource holons to compose a process for an order holon, we propose Petri net models to capture the workflows and activities in product holons and resource holons, respectively. To optimize the cost in the composed manufacturing process, the concept of activity-based costing is adopted to assign the cost of the activities to Petri nets. The advantages of our design methodology include specification of workflows and resource activities with PNML to minimize the cost. To realize the two-layer contract net protocol relies on a mechanism for a holon to discover the services provided by other holons. We proposed a scheme for publication and discovery of holon services based on FIPA compliant multi-agent system platform. Based on the service publication and discovery scheme, interactions between holons with the two-layer contract net protocol can be realized. We develop a HMS system to solve the process composition problem.     

Soundness-preserving reduction rules for reset workflow nets

The application of reduction rules to any Petri net may assist in its analysis as its reduced version may be significantly smaller while still retaining the original net’s essential properties. Reset nets extend Petri nets with the concept of a reset arc, allowing one to remove all tokens from a certain place. Such nets have a natural application in business process modelling where possible cancellation of activities need to be modelled explicitly and in workflow management where such process models with cancellation behaviours should be enacted correctly. As cancelling the entire workflow or even cancelling certain activities in a workflow has serious implications during execution (for instance, a workflow can deadlock because of cancellation), such workflows should be thoroughly tested before deployment. However, verification of large workflows with cancellation behaviour is time consuming and can become intractable due to the state space explosion problem. One way of speeding up verification of workflows based on reset nets is to apply reduction rules. Even though reduction rules exist for Petri nets and some of its subclasses and extensions, there are no documented reduction rules for reset nets. This paper systematically presents such reduction rules. Because we want to apply the results to the workflow domain, this paper focusses on reset workflow nets (RWF-nets), i.e. a subclass tailored to the modelling of workflows. The approach has been implemented in the context of the workflow system YAWL.     

A Petri net representation of Bayesian message flows: importance of Bayesian networks for biological applications

This article combines Bayes’ theorem with flows of probabilities, flows of evidences (likelihoods), and fundamental concepts for learning Bayesian networks as biological models from data. There is a huge amount of biological applications of Bayesian networks. For example in the fields of protein modeling, pathway modeling, gene expression analysis, DNA sequence analysis, protein–protein interaction, or protein–DNA interaction. Usually, the Bayesian networks have to be learned (statistically constructed) from array data. Then they are considered as an executable and analyzable model of the data source. To improve that, this work introduces a Petri net representation for the propagation of probabilities and likelihoods in Bayesian networks. The reason for doing so is to exploit the structural and dynamic properties of Petri nets for increasing the transparency of propagation processes. Consequently the novel Petri nets are called “probability propagation nets”. By means of examples it is shown that the understanding of the Bayesian propagation algorithm is improved. This is of particular importance for an exact visualization of biological systems by Bayesian networks.     

基于C＋＋的城市报建工作流petri网的算法设计

城市报建工作是一个阳光工程,在信息技术发展的今天,实现城市报建工作的网络化管理,通过建立城市报建工作流的petri网,设计相应的计算机算法来实现计算机程序化管理。文中重点设计了报建审批工作流的Petri网,依据工作流的Petri网,应用C＋＋语言设计报建工作主控模块的算法。     

基于高级Petri网的仿真剧情正规校核方法

针对仿真剧情主观校核不理想这一问题，提出了基于高级Petri网的仿真剧情正规校核方法．首先给出仿真剧情的形式化定义，并分析仿真剧情可能存在的错误类型；其次给出仿真剧情到高级Petri网的映射途径，并给出基于高级Petri网的仿真剧情校核准则和算法，此外，还给出实现仿真剧情动态校核的推理规则和机制；最后给出了一个正规校核工具框架．实际应用已经证明了该方法的有效性．     

On the relationship between workflow models and document types

The best practice in information system development is to model the business processes that have to be supported and the database of the information system separately. This is inefficient because they are closely related. Therefore we present a framework in which it is possible to derive one from the other. To this end we introduce a special class of Petri nets, called Jackson nets, to model the business processes, and a document type, called Jackson types, to model the database. We show that there is a one-to-one correspondence between Jackson nets and Jackson types. We illustrate the use of the framework by an example.