Workflow modeling for virtual processes: an order-preserving process-view approach

Conducting workflow management allows virtual enterprises to collaboratively manage business processes. Given the diverse requirements of the participants involved in a business process, providing various participants with adequate process information is critical to effective workflow management. This work describes a novel process-view, i.e., an abstracted process which is derived from a base process to provide process abstraction, for modeling a virtual workflow process. The proposed process-view model enhances the conventional activity-based process models by providing different participants with various views of a process. Moreover, this work presents a novel order-preserving approach to derive a process-view from a base process. The approach proposed herein can preserve the original ordering of activities in the base process. Additionally, a formal model is presented to define an order-preserving process-view. Finally, an algorithm is proposed for automatically generating an order-preserving process-view. The proposed approach increases the flexibility and functionality of workflow management systems.     

基于改进AOV网的轻量级工作流模型研究与设计

针对现有工作流模型在应对大型复杂系统时的不足,引入轻量级模型的概念,提出一种基于改进AOV网的轻量级工作流模型以满足大型复杂业务流程的工作流管理需求。在对模型进行详细定义与设计的同时,给出了流程调度中关键的两个算法--分支的调度算法及汇聚的同步算法以确保流程的准确运行。通过对一个具体实例的流程建模分析,体现了模型的轻量级优势并采用图论的分析手段对模型进行静态及动态验证,证明了模型的合理性。     

基于图形展开及图形归约的过程模型验证方法

工作流过程模型是业务过程的形式化定义，在业务过程的分析、运行和重组方面起着关键性的作用．为了实现预期的业务目标，需要正确地定义工作流过程模型，它的正确性直接影响业务目标的实现，WfMS开始调度执行之前必须对其进行分析．针对大规模复杂应用的特点和业务过程执行的实际需要，对复杂工作流过程模型的正确性验证进行了研究；基于有向有环图(DCG图)详细讨论工作流过程模型的局部错误以及过程逻辑错误；给出了过程建模中避免错误的相关约束规则；另外了提出了一种新型的图形归约和图形展开相结合的验证方法及过程模型验证算法．     

基于多色集合理论的工作流过程交互建模

为研究不同系统间工作流过程的交互问题, 基于多色集合理论构建了工作流过程交互矩阵和工作流过程交互多色图模型. 首先, 将元组与多色集合理论相结合, 形成多元素二元组多色集合与单元素二元组多色集合. 其次, 对围道矩阵进行扩展, 构成K元组围道矩阵和它的析取、合取、连接运算, 并对多色图中的节点进行区域划分以表示活动间交互所需的资源与消息. 最后, 构建系统间交互以及工作流过程交互模型, 用医院的HIS与RIS间工作流的交互为例进行验证.     

流程业务化定制中的工作流建模方法研究

针对流程业务化定制的需求,提出了一套面向业务人员的、直观易用的工作流建模方法.首先定义了一种基于有向图的工作流模型.在该模型的基础上,通过设置建模规则来规范业务人员的建模行为,使得无需模型验证就能够保证所建过程模型的正确性,从而回避了传统的有向图方法在模型分析方面的缺陷.最后将这套建模方法转化为Petri网的形式来描述,并利用Petri网的分析技术证明了该方法的可靠性.     

Improving workflow modularity using a concern-specific layer on top of Unify

Workflows are a popular means of automating processes in many domains, ranging from high-level business process modeling to lower-level web service orchestration. However, state-of-the-art workflow languages offer a limited set of modularization mechanisms. This results in monolithic workflow specifications, in which different concerns are scattered across the workflow and tangled with one another. This hinders the design, evolution, and reusability of workflows expressed in these languages. We address this problem through the Unify framework. This framework enables uniform modularization of workflows by supporting the specification of all workflow concerns – including crosscutting ones – in isolation of each other. These independently specified workflow concerns are connected to each other using workflow-specific connectors. In order to further facilitate the development of workflows, we enable the definition of concern-specific languages (CSLs) on top of the Unify framework. A CSL facilitates the expression of a family of workflow concerns by offering abstractions that map well to the concerns' domain. Thus, domain experts can add concerns to a workflow using concern-specific language constructs. We exemplify the specification of a workflow in Unify, and show the definition and application of two concern-specific languages built on top of Unify.     

支持企业经营过程重组的工作流仿真技术研究

企业经营过程的建模、分析和基于模型的企业 经营过程重组实施是确保企业成功实现经营过程优化重组的三个重要阶段．工作流管理是一 种能够有效的支持这三个阶段的信息技术．至今为止,工作流模型的仿真还是一个比较薄弱 的环节．本文提出了一种基于虚拟运行环境的工作流仿真方法,通过建立工作流虚拟运行环 境,以仿真引擎模拟活动的执行,自动处理过程中的半自动化活动或人工活动,并采用规则 与随机变量相结合的方法处理仿真过程中遇到的不确定因素,从而完成工作流仿真．为了增 强仿真的可信度和可视性,本文将虚拟现实技术引入仿真过程的动画显示．本文介绍了工作 流虚拟运行环境的构成,环境中核心组件（仿真引擎）的工作方式,并讨论了基于代理的虚 拟环境实现．     

Petri网在商务工作流建模中的应用研究

在工作流建模研究中,Petri网是一类重要工具。对于跨机构的商务工作流来说,用基本Petri网建模往往会因为图幅规模过大和细节过多而使得其可读性下降。该文提出了一种活动/层次网(A/H-Nets)模型,并给出了建模过程和应用示例。模型通过引入复合位置和子网转移及过程转移的概念,来满足Petri网在不同层次上建模的需求。为了保证层次之间的一致性,文中给出了层次建模必须的子网(过程)替换规则。     

ObjectFlow: Towards a process management infrastructure

As businesses feel competitive and economic pressures to automate and streamline their operations, they examine their day-to-day business processes and look to business process reengineering pratices to provide solutions. Improved networking capabilities and the widescale adoption of open systems architectures have allowed businesses to tie their information systems together and share data across departments. The challenge now involves coordinating and automating the flow of work between people and groups in an organization. This has prompted the emergence of a new kind of infrastructure, workflow enabler, which provides a model for business processes, and a foundation on which to build solutions supporting the execution and management of business processes. This article examines the technology trends, business benefits, and requirements which have lead to this development. It describes the logical structure and an operational model of an open workflow system, and positions ObjectFlow, a software product, within this framework to illustrate the concepts.     

具有安全特性的工作流管理系统框架

工作流就是活动及活动之间的变化过程表示的业务流程.工作流管理系统的主要目的就是对业务过程中各活动发生的先后次序及同活动相关的资源的调用进行管理,而实现业务过程的自动化.结合工作流管理联盟给出的工作流管理系统参考模型[1]和接口[3～7],综合描述了工作流管理系统的六个功能模块、五个接口和各个模块间传递的数据,细化管理监控模块,形成了一个具有授权、访问控制等安全服务的工作流管理系统框架.     

基于层次泳道的业务流程最优化建模

业务流程技术是企业管理、应用和集成领域的一个研究热点,而业务流程建模是其应用中的关键问题之一。针对流程建模自动化程度低、缺乏有效评价等不足,提出了基于层次泳道的最优化建模方法。该方法只需给出流程各活动的描述,便可根据活动间的推演关系自动构建流程全图;然后对可能流程进行层次泳道化;最后,综合流程的执行代价和泳道的均衡度,从层次泳道化模型中选择最优者为最终的业务流程建模。结合遗传算法对港口集装箱业务流程进行了最优化建模。实际应用表明,该方法建立的业务流程能有效地均衡码头的业务负载,提高码头的作业效率。     

Ensuring reliability in B2B services: Fault tolerant inter-organizational workflows

In the age of Business-to-Business (B2B) collaboration, ensuring reliability of workflows underlying inter-organizational business processes is of significant importance. There are, however, quite a few challenges towards achieving seamless operation. Such challenges arise from heterogeneity in infrastructure and coordination mechanism at participant organizations, as well as time and cost associated with recovery from failure. Our research presents foundations for a reliable scheme for recovery from failure of workflow processes spanning through multiple business entities. First, a system model is adapted from the mobile computing literature that serves to establish the requirements to be enforced by each participating organization. In our model, we adopt the Maximal Sequence Path (MSP) approach from Yoo et al. (Lecture Notes in Artificial Intelligence 2132:222–236, 2001), as a means of decomposing workflows into mobile agent-driven processes that communicate via web services at each organization. This decomposition ensures defining logical points within the dynamics of a workflow instance for locating accurate and consistent states of the system for recovery in case of a failure. Then, a set of algorithms for various business scenarios are developed and presented as practical solutions. These algorithms are shown to create checkpoints such that the system is always in a globally consistent state. As such, these algorithms constitute a set of standards that can be incorporated in business process management suites that support reliable inter-organizational collaboration.     

Conflict detection and resolution for workflows constrained by resources and non-determined durations

The correctness of a workflow specification is critical for the automation of business processes. Therefore, errors in the specification should be detected and corrected at build-time. In this paper, we present a conflict verification and resolution approach for a kind of workflow constrained by resources and non-determined duration based on Petri net. In this kind of workflow, there are two timing functions for each activity to present the minimum and maximum duration of each activity, and the implementations of some activities require resources. Based on the Petri net model obtained, the earliest time to start each activity can be calculated and the key activities influencing the implementation of the workflow can be determined, with which the resource consistency between activities can be verified. Key-activity and waiting-short priority strategies are adopted to remove the resource conflicts between activities, which can ensure that most of the subsequent activities start as early as possible and that the whole workflow be finished in a shorter time. Through experiments, it is proved that the proposed removal strategy for resource conflicts is better than other strategies.     

Standards-based approaches to B2B workflow integration

E-business automates the overall activities of a company and allows distributed systems to communicate their information. Process automation and information sharing improve a company’s productivity and responsiveness, while Business-to-Business (B2B) workflow systems electronically aid the progress of business processes among trading partners, and also help companies to monitor and administrate their process execution. This study analyzes the technologies and standards for B2B workflow integration, and extracts a reference model for B2B workflow integration. Based on the reference model, three approaches to B2B workflow integration will be introduced here. In addition, we have developed a prototype system of one approach and have illustrated an example for B2B workflow integration. The result of our research can help business partners understand the workflow standards and the messaging technologies for B2B workflow integration, and also help them understand how to implement workflow integration systems that are appropriate to their e-business environments.     

基于Pi-演算的扩展有向图工作流模型及验证

为了加强工作流模型对业务流程的描述能力,提出了一种扩展有向图工作流模型及其验证方法.针对基于有向图工作流模型的不足,提出了扩展有向图工作流模型,并给出了该模型的定义和图形符号描述.在用Pi-演算准确描述扩展有向图工作流模型的基础上,给出了用Pi-演算分析和验证扩展有向图工作流模型正确性的方法.最后,结合实验对扩展有向图工作流模型及验证方法进行了仔细分析,实验结果表明了该工作流模型及验证方法的有效性和正确性.     

From Contracts to E-Contracts: Modeling and Enactment

Contracts are complex to understand, represent and process electronically. Usually, contracts involve various entities such as parties, activities and clauses. An e-contract is a contract modeled, specified, executed and enacted (controlled and monitored) by a software system (such as a workflow system). Workflows are used to automate business processes that govern adherence to the e-contracts. E-contracts can be mapped to inter-related workflows, which have to be specified carefully to satisfy the contract requirements. Most workflow models do not have the capabilities to handle complex inter/intra relationships among entities in e-contracts. An e-contract does not adhere to activity/task oriented workflow processes, thus generating a gap between a conceptual model of e-contract and workflow. In this paper, we describe conceptual modeling of e-contracts and present a business process model for e-contract enactment. The enactment of e-contracts necessitates dynamic generation and initiation of workflows during the e-contract execution, besides the static workflows. ER^EC business process model facilitates an integrated approach to e-contracts enactment. Our methodology is illustrated by means of a case study conducted using Financial Messaging Solution contract for banking transactions.     

Authorized workflow schemas: deciding realizability through \mathsf{LTL }(\mathsf{F }) model checking

Many business processes are modeled as workflows, which often need to comply with business rules, legal requirements, and authorization policies. Workflow satisfiability is the problem of determining whether there exists a workflow instance that realizes the workflow specification while simultaneously complying with such constraints. This problem has already been studied by the computer security community, with the development of algorithms and the study of their worst-case complexity. These solutions are often tailored to a particular workflow model and are, therefore, of little or no use in analyzing different models; their worst-case complexities are likely to be an unreliable judge of their feasibility; and they lack support for other forms of analysis such as the determination of the smallest number of users required to satisfy a workflow specification. We propose model checking of an NP-complete fragment $\mathsf{LTL }(\mathsf{F })$ of propositional linear-time temporal logic as an alternative solution. We report encodings in LTL(F) that can compute a set of solutions (thus deciding satisfiability), compute minimal user bases and a safe bound on the resiliency of satisfiability under the removal of users. These theoretical contributions are validated through detailed experiments whose results attest to the viability of our proposed approach.