一种基于资源约束的工作流建模及分析方法

资源约束是工作流正确实施的一个瓶颈问题,因此工作流系统的资源建模及模型正确性验证方法显得非常重要.为此,基于Petri网和工作流建模方法,提出了一种资源约束的工作流系统的形式化建模和分析技术,定义了资源空间(RS)、资源子网、资源工作流网和资源工作流网完整性(soundness)的概念,建立了资源调用视图以及Petri网影射模型,得到了资源工作流网保持完整性判定的一个充要条件.该方法将系统资源建模和过程建模合成到一个模型中,解决了工作流系统资源和过程分别建模给系统的正确性验证带来的困难,为工作流系统资源状态的可视化和进行有效的系统验证提供了模型依据.给出的实例验证了模型的有效性.     

基于时间Petri网的工作流系统模型的线性推理

目前工作流理论的研究主要集中在工作流管理模型的结构及正确性分析,很少有人研究与时间有关的工作流模型的性质,特别是模型中的时序关系推理及性能计算问题.本文重点研究了这方面的问题,用时间Petri网表示工作流模型并对基本工作流模型进行时序分析,给出线性时间推理的规则,运用这些规则,可对复杂的工作流模型进行逐步化简,并在线性时间复杂度内解决时间推理问题.     

基于策略的工作流系统研究

结合互联网工程任务组(Internet Engineering Task Force,IETF)提出的策略的概念和策略部署模型,提出了一种基于策略的工作流系统,并结合工作流系统的特点,提出了描述工作流策略语言,并给出了使用基于策略扩展的Petri网建立工作流过程模型的方法。基于该元模型的定义的工作流具有较好的灵活性,并对工作流的运行期实例的动态修改提供了支持。     

基于反省技术的灵活工作流管理系统

面对复杂多样的应用环境,灵活性成为工作流技术研究的重点之一.反省作为提高系统灵活性的重要技术手段也可用于工作流管理系统中.本文分别从结构和行为方面对工作流过程及其管理进行了具体化,进而建立其反省模型.为了方便对元级的抽象和编程操纵,我们提出了元对象协议模型,其中包括协议声明、元对象关联、协议选择和元对象管理等机制或方法.进一步,本文通过典型的应用说明了反省方法对提高工作流系统灵活性和适应性是有效的.最后,文章介绍了工作流管理系统中反省技术的实现方法.     

一个支持动态变化的工作流元模型

支持动态可变和灵活的工作流系统是人们在实际应用中对工作流系统提出的新要求,传统的工作流建模思想必须加以改进以适应这种可动态变化的工作流运行模式.本文结合传统工作流的建模规律和动态变化的要求,提出了一个动态变化的三维空间元模型,将由过程模型、组织模型和信息模型组成的三维工作流模型从建模和运行变化的角度重新考虑,增加了对过程、活动、活动属性和组织模型的动态特性描述和操作协议描述,可以使在这个元模型之上的工作流模型具备人机交互能力和动态灵活性.元模型在工作流的建立阶段力求将动态特性进行描述和定义,在执行阶段可以在已定义的动态框架内变化,既保证了系统的灵活性,又使系统对动态变化具备可控操作.     

基于进程网的网上订餐流程描述

进程网既具有传统Petri网的图形化表示方式,又具有进程代数的语法形式,复杂进程网可由简单进程网通过组合算子组合而成,并支持自顶向下的建模方法。通过进程网描述网上订餐流程,有利于正确构造软件系统。     

基于同步网的工作流过程变动问题研究

支持动态可变的特性是实际应用对工作流系统提出的要求,已有的研究在表达能力和算法复杂度等方面存在问题.本文以形式化的工作流模型——同步网为基础,从逻辑和语义两个角度定义了过程变动,继而分类描述了基本变动操作,并讨论了变动的正确性问题.复杂的过程变动可以被分解为若干基本变动操作的序列,从而简化问题并且保证整个变动的正确性.在此之上提出了一种新的管理过程变动的方法,即以同步器为中心来管理过程实例的迁移问题.     

一类可由基本模型嵌套组成的工作流系统的性能分析方法

工作流是近年来网络领域里研究的一个热点,对工作流模型的性能分析是工作流研究的一个重要内容.实际的模型往往规模大而复杂,这为分析其性能带来了很大的困难.但有一类模型可由工作流的四种基本模型(顺序、并行、选择、循环)嵌套组成,对于这类模型,本文给出了计算其性能乘积解的数学公式.文中给出了如何由这四种基本模型嵌套组成实际模型的方法,推导出了计算这四种基本模型的性能等价公式,并按建立实际模型相反的顺序,用由里到外逐层的分析方法,给出了计算实际模型的性能乘积解.     

基于EPC的工作流建模及实现

针对现有工作流模型在支持过程定义和过程分析方面缺乏统一规范的缺点,提出了EPC的工作流建模方法.给出了EPC过程链中顺序路由和并行度的定义,建立了基于EPC建模的工作流过程模型,最后通过J2EE平台实现了基于EPC的工作流原型系统,并对电涡流缓速器产品协同设计的工作流建模实例进行了介绍.     

基于有向超图的工作流资源分配均衡优化方法

为了拓展工作流资源分配均衡优化的深度和广度,提出了一种考虑过程支持资源变化与过程结构变化相互影响的优化方法.通过对过程进行扩展超图建模,利用超图的性质以及活动能力需求集与支持资源能力集之间的耦合,给出了过程结构随支持资源变化而变化的形式化处理规则;给出了由不同结构过程构成的、用于工作流资源分配均衡优化超图模型(DHM-WRAB)的建模规则,使工作流资源分配均衡优化转化为具有权因子的超图最短路径求解问题,并给出求解过程;最后,通过举例证明该方法可行、有效.     

Dynamic Reconfiguration Based on Goal-Scenario by Adaptation Strategy

The self-adaptation of software systems is a complex process that depends on several factors that can change during the system operational lifetime. But, Today’s workflow management systems are only applicable in a secure and safe manner if the business process to be supported is well-structured and there is no need for ad hoc deviations at runtime. Hence, it is necessary to define mechanisms for providing a self-adaptive system the capability of reconfiguration during run-time the process that controls its adaptation. In this paper, we provide rapid dynamic reconfiguration using the workflow based on goal-scenario as the basis to set up strategies in accordance with the adaptive judgment. Also, we provide a sophisticated approach which fosters learning from past process changes by process variants through the order matrix. We present a formal foundation for the support of dynamic structural workflow changes of running. Our approach uses estimates based goal-scenario to determine which remaining parts of running workflows are affected by the external environment and is able to predictively perform suitable adaptation. This helps to ensure that necessary adaptation are performed in time with minimal user interaction which is especially valuable in change of external environment.     

Modeling search in group decision support systems

Groups using group decision support systems (GDSS) to address particular tasks can be viewed as performing a search. Such tasks involve arriving at a solution or decision within the context of a complex search space, warranting the use of computerized decision support tools. The type of search undertaken by the groups appears to be a form of adaptive, rather than enumerative, search. Recently, efforts have been made to incorporate this adaptation into an analytical model of GDSS usage. One possible method for incorporating adaptation into an analytical model is to use an evolutionary algorithm, such as a genetic algorithm (GA), as an analogy for the group problem-solving process. In this paper, a test is made to determine whether GDSS behaves similarly to a GA process utilizing rank selection, uniform crossover, and uniform mutation operators. A Markov model for GAs is used to make this determination. Using GDSS experimental data, the best-fit transition probabilities are estimated and various hypotheses regarding the relation of GA parameters to GDSS functionality are proposed and tested. Implications for researchers in both GAs and group decision support systems are discussed.     

基于Petri网的工作流过程建模和时间性能分析

介绍了基于Petri网的工作流建模技术,并针对一个复杂的企业生产经营活动的流程构建了一个简化灵活的模型,利用随机Petri网的性能分析方法对建立的模型进行了时间性能分析。结果表明,文中的性能分析方法可对复杂的模型进行有效地简化分析。     

信息系统生存性分析模型研究

基于信息系统的开放复杂性,将整个生存性分析问题划分为环境、系统以及具体分析过程三个方面并分别进行建模:利用工作流的概念,提出了系统的层次模型;利用事件情景来表示环境对系统的作用,并通过事件分级以及不同级别事件集的分布权值调整表示各种环境;提出了基于FSM的分析过程模型,通过系统状态的层次结构,将传统的基于系统状态的直接分析转化为间接的层次分析。事件的量化使得该分析模型具有一定的量化分析应用前景。     

An Incremental Approach to the Analysis and Transformation of Workflows Using Region Trees

The analysis of workflows in terms of structural correctness is important for ensuring the quality of workflow models. Typically, this analysis is only one step in a larger development process, followed by further transformation steps that lead from high-level models to more refined models until the workflow can finally be deployed on the underlying workflow engine of the production system. For practical and scalable applications, both analysis and transformation of workflows must be integrated to allow incremental changes of larger workflows. In this paper, we introduce the concept of a region tree (RT) for workflow models that can be used as the central data structure for both workflow analysis and workflow transformation. An RT is similar to a program structure tree and imposes a hierarchy of regions as an overlay structure onto the workflow model. It allows an incremental approach to the analysis and transformation of workflows, and thereby, significantly reduces the overhead because individual regions can be dealt with separately. The RT is built using a set of region-growing rules. The set of rules presented here is shown to be correct and complete in the sense that a workflow is region-reducible as defined through these rules if and only if it is semantically sound.     

A Hierarchical Modeling and Fault Diagnosis Method for Complex Electronic Devices

Due to the shortcomings of the diagnosis systems for complex electronic devices such as failure models hard to build and low fault isolation resolution, a new hierarchical modeling and diagnosis method is proposed based on multisignal model and support vector machine （SVM）. Multisignal model is used to describe the failure propagation relationship in electronic device system, and the most probable failure printed circuit boards （PCBs） can be found by Bayes inference. The exact failure modes in the PCBs can be identified by SVM. The results show the proposed modeling and diagnosis method is effective and suitable for diagnosis for complex electronic devices.     

基于J2EE面向服务的工作流管理系统

Web服务技术的蓬勃发展,进一步促进了面向服务架构(SOA)的繁荣,越来越多的组织机构已经或正在准备接纳这一新技术来构建基于Web服务的应用.传统的工作流管理系统已经不能满足业务集成的需要,新一代的工作流管理系统必须提供对Web服务的支持.文中提出了一个称为"SOFlow"的面向服务的工作流管理系统,并对该系统的体系架构进行了分析,给出了该系统的一个具体实现.     

A new health estimation model for CNC machine tool based on infinite irrelevance and belief rule base

To guarantee the normal workflow and determine scheme of optimal maintenance, it is important to accurately estimate the health condition of computerized numerical control (CNC) machine tool. In current studies, the health condition of CNC machine tool is modeled by using one feature. Due to the complexity of CNC machine tool, the estimating accuracy of the current models is poor and real-time performance cannot be satisfied when multiple features are chosen. Moreover, it is difficult to obtain more effective monitoring data when the CNC machine tool is from normal to failure. To solve the problems, based on infinite irrelevance and belief rule base (BRB), a health estimation model which is named as the infinite irrelevance BRB model is proposed in this paper. In particular, the infinite irrelevance method is used to select key features to optimize the model structure, and BRB is applied to estimate the health condition according to the monitoring data and expert knowledge. Thus, the quantitative monitoring data and expert knowledge can be used effectively to improve accuracy and real-time performance of health estimation. Furthermore, because the initial values of the parameters in the proposed infinite irrelevance BRB model given by experts may not be accurate, the constraint covariance matrix adaptation evolution strategy (CMA-ES) algorithm is employed to train the parameters. A case study for the servo system of the CNC milling machine is used to verify the effective and accuracy of the proposed model. The results show that the infinite irrelevance BRB model can accurately estimate the health condition of the servo system.