基于WF-net的工作流建模技术及应用

工作流系统成功的关键在于向其输入的工作流的质量,因此工作流的建模就显得非常重要。工作流网（WF—net）是由Petri网发展起来的一种适用于多种系统的图形化、数学化建模工具。首先它有精确的定义,其次这种形式化体系可以用来反思过程,所以它是一种严格的过程形式化体系。讨论WF-net的建模技术,并以办公自动化系统中收文为例说明其应用,并分析其在众多的建模工具中所具有的优势。     

基于案例推理的柔性工作流建模技术研究

针对工作流模型难以描述创建时的不确定因素的问题,研究了一种基于“柔性块”的柔性工作流建模技术。运行时,柔性块先以Ad hoc方式执行,运行历史数据积累到一定程度后,通过过程挖掘得到柔性块内部模型,并在以后执行时匹配应用场景,采用交互式基于案例的推理方法获得柔性块模型。实际应用表明该方法能复用建模知识,柔性块建模效率随着其执行次数增多而提高,工作流模型具有较高的柔性。     

工作流重构技术研究

先进的工作流技术与传统的企业管理信息系统相结合,日益成为提高企业信息化的一个重要手段。目前的工作流是基于模型驱动的,定义一个完整的模型是相当复杂和费时的;而且,实际业务流程同流程模型之间必然存在差异。本文介绍了工作流网,工作流日志的概念;提出了一种基于日志包含的信息来重构业务流程模型的算法,该算法还能处理日志中的干扰信息和有效地度量流程模型和实际业务流程之间的差异。     

进化算法中的模式定理及建筑块

探讨了进化算法中的模式定理及建筑块理论．通过引入模式进化、模式进化能力、适度模式等概念，以标准遗传算法为例，证明了在变异算子独立的条件下，进化算法中模式的构成与多点交叉和变异的顺序无关，然后证明了具有强进化能力的模式，将以指数阶增长．该文的模式理论有别于Holland等人提出的模式理论，特别是在交叉算子上采用了多点交叉算子，给出了相应的公式；并从这一推导过程论证了建筑块假设的合理性，可以称之为建筑块理论．     

Workflow evolution

A basic step towards flexibility in workflow systems is the consistent and effective management of workflow evolution, i.e. of changing existing workflows while they are operational. One of the most challenging issue is the handling of running instances when their schemata are modified: simple solutions can be devised, but they often imply losing all the work done or failing in capturing the advantages offered by workflow modifications; this is unacceptable for many applications. In this paper we address the problem of workflow evolution, from both a static and a dynamic point of view. We define a complete, minimal, and consistent set of modification primitives that allow modifications of workflow schemata and we introduce a taxonomy of policies to manage evolution of running instances when the corresponding workflow schema is modified. Formal criteria are introduced, based on a simple workflow conceptual model, in order to determine which running instances can be transparently migrated to the new version. A case study, relating the assembling of a desktop computer, will exemplify the introduced concepts.     

基于Pi演算的跨组织工作流建模研究

传统的工作流建模方法主要用于描述组织内部流程,因而难以描述跨组织工作流面向流程、组合、抽象、涉及多个自治系统通信合作的新特点.针对此问题,提出了一种基于Pi演算的跨组织工作流建模方法,利用Pi演算的并发计算操作符,将跨组织业务流程建模为一组自治且并发执行的组织内子流程的组合,子流程建模为组织内本地流程定义和组织间控制约束的组合.基于Pi演算的弱互相似理论,验证了两个跨组织子流程外部行为的相等性,用于帮助组织内私有流程的外部抽象.基于该方法建立的跨组织工作流模型在子流程间建立了一种松耦合的关系,适用于动态的跨组织环境,同时基于严格的形式化方法,便于分析和验证.     

REASONING FOR AUTOMATED MODEL INTEGRATION

This paper investigates some reasoning issues involved in developing an integrated modeling environment called a model management system. A model management system is a computer-based environment designed to support effective development and utilization of quantitative decision models. Since the construction of decision models is a knowledge-intensive process, reasoning plays a critical role. Reasoning is particularly important when automated model integration is needed in a large-scale system. In this case, heuristics are required to reduce the complexity of the process. This paper examines the planning and automated formulation of complex models from smaller building blocks. First, a hierarchy of abstractions that integrates previous contributions in model management is presented. Then, a modeling process is formulated as a planning process by which a set of operators are scheduled to achieve a specific goal. This process involves searches for alternatives that can eliminate the difference between the initial stale and the goal state. Various reasoning strategies and heuristic evaluation Junctions that can be used to improve the efficiency of developing a master plan for model integration are discussed.     

Workflow simulation for operational decision support using event graph through process mining

It is increasingly common to see computer-based simulation being used as a vehicle to model and analyze business processes in relation to process management and improvement. While there are a number of business process management (BPM) and business process simulation (BPS) methodologies, approaches and tools available, it is more desirable to have a systemic BPS approach for operational decision support, from constructing process models based on historical data to simulating processes for typical and common problems. In this paper, we have proposed a generic approach of BPS for operational decision support which includes business processes modeling and workflow simulation with the models generated. Processes are modeled with event graphs through process mining from workflow logs that have integrated comprehensive information about the control-flow, data and resource aspects of a business process. A case study of a credit card application is presented to illustrate the steps involved in constructing an event graph. The evaluation detail is also given in terms of precision, generalization and robustness. Based on the event graph model constructed, we simulate the process under different scenarios and analyze the simulation logs for three generic problems in the case study: 1) suitable resource allocation plan for different case arrival rates; 2) teamwork performance under different case arrival rates; and 3) evaluation and prediction for personal performances. Our experimental results show that the proposed approach is able to model business processes using event graphs and simulate the processes for common operational decision support which collectively play an important role in process management and improvement.     

基于对象和实例互操作行为模型的工作流研究

通过工作流程逻辑领域和活动领域的划分,建立了逻辑领域的过程对象和活动领域的活动实例局部互操作行为模型和全局互操作行为模型,并分别对这两个行为模型内部的互操作逻辑关系进行了分析和研究,从对象和实例集成的角度对工作流的运作机理进行了探讨,为实现工作流模型的扩展和行为活动的复用提供了理论基础。并通过实例对工作流过程对象和活动实例全局互操作行为模型的运作关系进行了阐述和说明。     

一种基于库所含时间因素的时延Petri网的工作流建模方法

时间是反映工作流性能的一个重要方面,立足于实际业务过程对工作流系统时间管理功能的需求,尤其是针对一些对时间性能要求比较高的工作流系统,提出一种新的基于库所含时间因素的时延Petri网的工作流建模和分析方法,提出一种新的工作流建模工具TPWF—NET（Timed Places Work Flow—Net）,并给出结构完整性的验证方法。     

Workflow simulation for operational decision support

Simulation is widely used as a tool for analyzing business processes but is mostly focused on examining abstract steady-state situations. Such analyses are helpful for the initial design of a business process but are less suitable for operational decision making and continuous improvement. Here we describe a simulation system for operational decision support in the context of workflow management. To do this we exploit not only the workflow’s design, but also use logged data describing the system’s observed historic behavior, and incorporate information extracted about the current state of the workflow. Making use of actual data capturing the current state and historic information allows our simulations to accurately predict potential near-future behaviors for different scenarios. The approach is supported by a practical toolset which combines and extends the workflow management system YAWL and the process mining framework ProM.     

A conceptual approach to modeling the procurement process of construction using petri-nets

One way to improve the efficiency and effectiveness of procurement processes is to improve the timeliness of information flows between and among project participants. This can be achieved by condensing sequential processes into concurrent processes that are synchronized so their effectiveness and efficiency can be improved. Essentially existing processes (workflows) are re-designed so that savings in time and cost can be achieved. In order to identify and design the optimum workflow, it is important to have an effective modeling language to describe and simulate the actual operational process. Recently, Petri-Nets (PN) have been used in the manufacturing industry as a tool to analyze the concurrency of operations. Research results indicate that PNs are a useful tool for formalizing, simulating, and designing systems and processes that communicate with one another and need to be synchronized. This paper presents a simple introductory experiment to demonstrate how PNs can be used to simulate workflow in order to identify the optimum procurement process. Initial results from the experiments are reported in the paper.     

Visualization workflows for level-12 HUC scales: Towards an expert system for watershed analysis in a distributed computing environment

Visualization workflows are important services for expert users to analyze watersheds when using our HydroTerre end-to-end workflows. Analysis is an interactive and iterative process and we demonstrate that the expert user can focus on model results, not data preparation, by using a web application to rapidly create, tune, and calibrate hydrological models anywhere in the continental USA (CONUS). The HydroTerre system captures user interaction for provenance and reproducibility to share modeling strategies with modelers. Our end-to-end workflow consists of four workflows. The first is data workflows using Essential Terrestrial Variables (ETV) data sets that we demonstrated to construct watershed models anywhere in the CONUS (Leonard and Duffy, 2013). The second is data-model workflows that transform the data workflow results to model inputs. The model inputs are consumed in the third workflow, model workflows (Leonard and Duffy, 2014a) that handle distribution of data and model within High Performance Computing (HPC) environments. This article focuses on our fourth workflow, visualization workflows, which consume the first three workflows to form an end-to-end system to create and share hydrological model results efficiently for analysis and peer review. We show how visualization workflows are incorporated into the HydroTerre infrastructure design and demonstrate the efficiency and robustness for an expert modeler to produce, analyze, and share new hydrological models using CONUS national datasets.     

An automated vision-based method for rapid 3D energy performance modeling of existing buildings using thermal and digital imagery

Modeling the energy performance of existing buildings enables quick identification and reporting of potential areas for building retrofit. However, current modeling practices of using energy simulation tools do not model the energy performance of buildings at their element level. As a result, potential retrofit candidates caused by construction defects and degradations are not represented. Furthermore, due to manual modeling and calibration processes, their application is often time-consuming. Current application of 2D thermography for building diagnostics is also facing several challenges due to a large number of unordered and non-geo-tagged images. To address these limitations, this paper presents a new computer vision-based method for automated 3D energy performance modeling of existing buildings using thermal and digital imagery captured by a single thermal camera. First, using a new image-based 3D reconstruction pipeline which consists of Graphic Processing Unit (GPU)-based Structure-from-Motion (SfM) and Multi-View Stereo (MVS) algorithms, the geometrical conditions of an existing building is reconstructed in 3D. Next, a 3D thermal point cloud model of the building is generated by using a new 3D thermal modeling algorithm. This algorithm involves a one-time thermal camera calibration, deriving the relative transformation by forming the Epipolar geometry between thermal and digital images, and the MVS algorithm for dense reconstruction. By automatically superimposing the 3D building and thermal point cloud models, 3D spatio-thermal models are formed, which enable the users to visualize, query, and analyze temperatures at the level of 3D points. The underlying algorithms for generating and visualizing the 3D spatio-thermal models and the 3D-registered digital and thermal images are presented in detail. The proposed method is validated for several interior and exterior locations of a typical residential building and an instructional facility. The experimental results show that inexpensive digital and thermal imagery can be converted into ubiquitous reporters of the actual energy performance of existing buildings. The proposed method expedites the modeling process and has the potential to be used as a rapid and robust building diagnostic tool.     

A Methodology for Data Schema Integration in the Entity Relationship Model

The conceptual design of databases is usually seen as divided into two steps: view modeling, during which user requirements are formally expressed by means of several user oriented conceptual schemata, and schema integration, whose goal is to merge such schemata into a unique global conceptual schema. This paper is devoted to describe a methodology for schema integration. An enriched entity relationship model is chosen as the data model. The integration process consists of three steps: first, several types of conflicts between the different user schemata are checked and solved; second, schemata are merged into a draft integrated schema, that is, third, enriched and restructured according to specific goals.     

E-MEMO: Referenzmodelle zur ökonomischen Realisierung leistungsfähiger Infrastrukturen für Electronic Commerce

For many companies, the development of a competitive E-Commerce strategy and even more so its implementation is a huge challenge. This paper presents a method that is aimed at reducing substantially cost and risk of such an endeavour. The method has been adapted from an existing method for multi-perspective enterprise modelling. It supports strategy analysis and design as well as the corresponding organisational design. It also fosters the configuration of supporting information systems. Besides specialized process models, the method offers reference models for strategy design and a library of business process models. The process models can be transformed automatically into workflow schemata.     

工作流网XPDL映射

工作流过程定义是工作流管理系统过程模型建立阶段的功能。工作流过程定义可以采取不同的建模方法,而工作流网是Petri网技术在过程定义中的具体应用。XPDL是工作流管理联盟提出的工作流过程定义语言,主要用于不同工作流产品过程定义之间的交换。文章在分析工作流网和XPDL特性的基础上,给出了工作流网向XPDL映射的方法。     

A problem-solving environment for data assimilation in air quality modelling

A generic toolbox for data assimilation called COSTA (COmmon Set of Tools for the Assimilation of data) makes it possible to simplify the application of data assimilation to models and to try out various methods for a particular model. Concepts of object oriented programming are used to define building blocks for data assimilation systems that can be exchanged and reused. The main building blocks in COSTA are the model component and the stochastic observer component. These components can be created by wrapping existing code. The LOTOS–EUROS air quality model will be used for operational smog and aerosol forecasts in the Netherlands in the near future. The COSTA framework will be used in this operational environment to implement the data assimilation techniques. As a first steps towards this operational system the model component of LOTOS–EUROS is created and the performance of various Kalman filter based data assimilation techniques are compared for a real live case study. The ensemble Kalman filter and the ensemble square-root filters converged faster than the other tested techniques for the selected case study setup.     

一种改进的软件测试流程实例的描述方法

提出了测试流程实例的操作语义描述方法,这种方法的使用弥补了工作流元模型对测试流程实例描述的不足,并在实际项目中得到了应用,包括过程实例的形式化描述和活动实例的形式化描述,以及状态转移规则的描述,取得了很好的效果。     

System-of-Systems Modeling and Simulation of a Ship Environment With Wireless and Intelligent Maintenance Technologies

Modeling and simulation environments are needed to support decision making in Navy Warfighters, which are emergent systems that pose a challenge to operations management. Ships consist of complex interconnected systems such as the infrastructure, crew, and workflow. A system-of-systems approach using agent-based modeling is applied here to develop workflow simulations involving a ship's crew conducting routine maintenance, watch duty, and reporting functions. Simple models are used to describe basic behavioral traits and intelligence in crew members; machinery including sensors for intelligent maintenance; equipment consuming power; mobile and stationary communication network access points; models for data transfer over the network; crew mobility models; power distribution and trimming models for the electrical system; and a fire model to simulate emergency scenarios. The simulation results demonstrate an increase in machine availability due to the implementation of intelligent maintenance systems. The effects of wireless-network usage on crew resource utilization and overall ship capability in normal operational scenarios are also demonstrated. A simple rescheduling algorithm is used to improve crew utilization and estimate manning requirements. The effects of emergency scenarios such as fires in different locations are also studied. Sensitivity analysis is presented to verify the developed model, and a note on validation is given.