注意：
您可以自由傳播，複製，修改本譯文（不包括英文原文，那是別人的東西，人家有版權的），不能用於商業用途，不能用這個譯文來賣錢或者做與錢有關的交易，只能做爲學習、提高技術水平之用。
您在修改的時候，必須包含本注意事項。並且註明本文原自http://blog.csdn.net/liufuyahong 。否則我保留一切起訴的權利。
2.工作流概述
2.1 什麼是工作流？
工作流是一些過程的自動操作，在這些過程裏，文檔，信息或者任務按照定義好的一系列規則在參與者之間傳遞，以完成或有益於整個業務目標。同時流程也可以手動組織，在實踐中，大部分的工作流通常組織在IT系統得環境中，爲這些程序化的自動操作提供計算機化的支持，WFMC直接指導在這個方面的工作。
定義：工作流
用計算機來簡化或自動化全部或部分業務過程。
工作流經常和業務流程重組(譯者注：即BPR）聯繫在一起，後者關係到評估，分析，建模，定義和確定一個組織（或其他業務實體）的核心業務處理操作的執行順序。BRP活動並不一定導致工作流的實施，但是工作流技術經常是一個恰當的解決方案，它提供分離的業務過程邏輯，其IT操作支持並讓接連發生的變化組合進定義了業務過程的程序化規則。相反地，工作流不一定要按照BPR的某些做法來實施，例如實現一個現有業務過程的自動化。
工作流管理系統提供業務處理過程的程序化自動操作，它管理各個工作活動的順序，調動適當的人力資源/IT資源，使他們按各種不同的活動步驟聯繫在一起。
定義：工作流管理系統
一種通過執行執行順序是由工作流邏輯的計算機表現驅動的軟件來完全定義、管理和執行“工作流”的系統。
一個單獨的業務過程的生命週期，根據其複雜性和各種組成活動的持續時間，可能從幾分鐘到幾天（甚至上月）。這樣的系統可能有多種實現方式，從本地工作組到跨國公司，會使用各種各樣的IT和通訊架構和操作。MFMC參考模型因此對工作流管理進行非常廣泛的觀察，其目的就是提供多種實現技術和表現這種技術的特徵的運行環境。
儘管類型多樣，但是，所有的WFM（譯者注：工作流管理）系統都表現出某些共性，這爲發展不同產品之間的整合和協同工作的能力提供了基礎。引用模型爲工作流系統的構造描述了一個公共的模型，並確定了它和各種可選實施途徑的關係。
在最高的層次，所有的WFM系統可能有具有體統3個功能領域的特徵：
1、構建時功能，這關係到定義——可能還關係到建模—— 工作流過程和它的組成活動。
2-運行時的控制功能，這關係到管理在運行環境中的工作流過程，按先後順序把各種活動當作其各自過程的一部分來處理
3、運行時用戶（人）和爲處理各種活動的步驟的各種IT應用工具之間的交互。
圖1表示了WFM系統的基本特徵以及這些主要功能之間的關係。
圖1 工作流系統特徵
2.1.1 構建時功能
構建時功能是指給出業務過程的定義,該定義能用計算機來處理的功能。在這個階段，通過使用一種或多種分析、建模和系統定義技巧，把一個業務過程從現實世界翻譯成一個格式化的，能被計算機處理的定義。該定義有時叫做過程模型，過程模版，過程元數據或者過程定義。本文使用“過程定義”這個術語。
定義：過程定義
過程的可以用計算機處理的表現方式，包括對手動操作的定義和對流程的定義。
一個過程定義通常由許多離散的活動步驟組成，由聯繫在一起的人/機操作和規則通過不同的活動步驟控制着過程的進度。過程定義可是文本的，圖形的形式，或者是某種形式語言符號。就如在上圖中的反饋箭頭指出的那樣，有些工作流系統可以允許動態的從運行時操作環境切換到過程定義。
聯盟成員沒有考慮把如何生成過程定義作爲標準化的領域，而且，考慮把這作爲市場上不同產品之間的主要區別。然而，構建時操作的成果——過程定義——被確定爲標準化的一個潛在領域，以便讓過程定義數據在不同構建時工具和運行時產品之間可以交換。
2.1.2 運行時的過程控制功能
在運行的時候，軟件根據過程的定義負責生成、控制過程的操作實力，在過程內按時序安排各種不同的活動的步驟，並調用適當的人力和IT應用等資源。這些運行時的過程控制功能充當着按照“過程定義”建模出來的過程和現實世界的過程的連接器，並由在運行時刻的人機交互體現出來。其核心組件就是基礎工作流管理控制軟件（或者叫做“引擎”），他負責過程的生成和刪除，控制着運行過程的各個活動的時序，控制着應用工具和人力資源之間的交互活動。這種軟件經常跨越分佈在多種不同的計算機平臺上，用以處理運行在不同地域基礎上的各種過程。
2.1.3 運行時活動的交互
在一個工作流內部的各個單個活動通常和人的操作有關，經常用特殊的IT工具（例如表單填寫）和信息處理操作一起表現，這種操作需要一些特殊的程序來操作某些定義好了的信息。和過程控制軟件之間的相互交互必須能夠在各個活動之間傳遞控制、確定過程的操作狀態、調用應用工具、傳遞適當的數據，如此等等。有一個支持這種類別的交互的標準框架有一些好處，可以使用一個統一的接口給多個工作流系統，並且可以開發一個公共的應用工具給不同的工作流產品。
2.1.4 分發和系統接口
在參與者之間分發任務和信息的能力是工作流運行時基礎結構的一個主要區別特徵。根據工作流的範圍，分發功能可能運行在各種層次上（從工作組到跨國公司）；它可能使用各種底層的通訊機制（電子郵件，消息傳遞，對象分發技術等等）。在圖2所表示的工作流結構的頂層試圖中，着重表現了這種分發特徵。
工作流制定服務作爲核心的基礎結構功能表現了出來，它帶有給分佈在跨工作流領域的用戶和應用的接口。每一個這些接口都是一個位於工作流制定服務和其他基礎結構或應用組件之間的潛在的整合點。
圖2流程制定服務內的分發
工作的流程可能包括在不同的供應商的工作流產品之間傳遞任務，使業務過程的不同部分發生在使用特殊產品適配這些過程的階段的，不同的平臺上或子網絡中。在這種場景中，在中心盒子中的流程在2個或更多的工作流產品間傳遞——例如活動1，2和5可能由1個工作流系統執行，而活動3和4由一個不同的系統執行——附帶在整個工作流內部在適當的點上傳遞控制。支持這種工作流控制傳輸的標準讓混合的工作流應用在使用幾個不同的工作流產品時就像一個單一的邏輯實體在運行。
因而由WFM聯盟定義的整個範圍的接口包括：
過程定義數據及這些數據交換的規範
支持不同工作流協同工作的接口
支持和不同IT應用類型交互的接口
支持和用戶界面——桌面功能——交互的接口
提供系統監視和公制功能的接口來簡化複合工作流應用環境的管理
這些將在第3章有進一步的闡述。
英文原文
2. Workflow Systems Overview
2.1. What is Workflow?
Workflow is concerned with the automation of procedures where documents, information or tasks are passed between participants according to a defined set of rules to achieve, or contribute to, an overall business goal. Whilst workflow may be manually organised, in practice most workflow is normally organised within the context of an IT system to provide computerised support for the procedural automation and it is to this area that the work of the Coalition is directed.
Definition - Workflow
The computerised facilitation or automation of a business process, in whole or part.
Workflow is often associated with Business Process Re-engineering, which is concerned with the assessment, analysis, modelling, definition and subsequent operational implementation of the core business processes of an organisation (or other business entity). Although not all BPR activities result in workflow implementations, workflow technology is often an appropriate solution as it provides separation of the business procedure logic and its IT operational support, enabling subsequent changes to be incorporated into the procedural rules defining the business process. Conversely, not all workflow implementations necessarily form part of a BPR exercise, for example implementations to automate an existing business procedure.
A Workflow Management System is one which provides procedural automation of a business process by management of the sequence of work activities and the invocation of appropriate human and/or IT resources associated with the various activity steps.
Definition - Workflow Management System
A system that completely defines, manages and executes “workflows” through the execution of software whose order of execution is driven by a computer representation of the workflow logic.
An individual business process may have a life cycle ranging from minutes to days (or even months), depending upon its complexity and the duration of the various constituent activities. Such systems may be implemented in a variety of ways, use a wide variety of IT and communications infrastructure and operate in an environment ranging from small local workgroup to inter-enterprise. The WFMC Reference Model thus takes a broad view of workflow management, which is intended to accommodate the variety of implementation techniques and operational environments which characterise this technology.
Despite this variety, all WFM systems exhibit certain common characteristics, which provide a basis for developing integration and interoperability capability between different products. The Reference Model describes a common model for the construction of workflow systems and identifies how it may be related to various alternative implementation approaches.
At the highest level, all WFM systems may be characterised as providing support in three functional areas:
TC00-1003 Issue 1.1 Workflow Reference Model Printed 19/11/98
. the Build-time functions, concerned with defining, and possibly modelling, the workflow process and its constituent activities
. the Run-time control functions concerned with managing the workflow processes in an operational environment and sequencing the various activities to be handled as part of each process
. the Run-time interactions with human users and IT application tools for processing the various activity steps
Figure 1 illustrates the basic characteristics of WFM systems and the relationships between these main functions.
Figure 1- Workflow System Characteristics
2.1.1. Build-time Functions
The Build-time functions are those which result in a computerised definition of a business process. During this phase, a business process is translated from the real world into a formal, computer processable definition by the use of one or more analysis, modelling and system definition techniques. The resulting definition is sometimes called a process model, a process template, process metadata, or a process definition. For purposes of this document, the term 'process definition' will be used.
Definition - Process Definition
The computerised representation of a process that includes the manual definition and workflow definition.
A process definition normally comprises a number of discrete activity steps, with associated computer and/or human operations and rules governing the progression of the process through the various activity steps. The process definition may be expressed in textual or graphical form or in a formal language notation. Some workflow systems may allow dynamic alterations to process definitions from the run-time operational environment, as indicated by the feed-back arrow in the above diagram.
Coalition members do not consider the initial creation of process definitions to be an area of standardisation. Rather, this is considered to be a major distinguishing area between products in the marketplace. However, the result of the Build-time operation, the process definition, is identified as one of the potential areas of standardisation to enable the interchange of process definition data between different build-time tools and runtime products.
2.1.2. Run-time Process Control Functions
At run-time the process definition is interpreted by software which is responsible for creating and controlling operational instances of the process, scheduling the various activities steps within the process and invoking the appropriate human and IT application resources, etc. These run-time process control functions act as the linkage between the process as modelled within the process definition and the process as it is seen in the real world, reflected in the runtime interactions of users and IT application tools. The core component is the basic workflow management control software (or "engine"), responsible for process creation & deletion, control of the activity scheduling within an operational process and interaction with application tools or human resources. This software is often distributed across a number of computer platforms to cope with processes which operate over a wide geographic basis.
2.1.3. Run-time Activity Interactions
Individual activities within a workflow process are typically concerned with human operations, often realised in conjunction with the use of a particular IT tool (for example, form filling), or with information processing operations requiring a particular application program to operate on some defined information (for example, updating an orders database with a new record). Interaction with the process control software is necessary to transfer control between activities, to ascertain the operational status of processes, to invoke application tools and pass the appropriate data, etc. There are several benefits in having a standardised framework for supporting this type of interaction, including the use of a consistent interface to multiple workflow systems and the ability to develop common application tools to work with different workflow products.
2.1.4. Distribution & System Interfaces
The ability to distribute tasks and information between participants is a major distinguishing feature of workflow runtime infrastructure. The distribution function may operate at a variety of levels (workgroup to inter-organisation) depending upon the scope of the workflows; it may use a variety of underlying communications mechanisms (electronic mail, messaging passing, distributed object technology, etc). An alternative top-level view of workflow architecture which emphasises this distribution aspect is shown in figure 2 on the following page.
The workflow enactment service is shown as the core infrastructure function with interfaces to users and applications distributed across the workflow domain. Each of these interfaces is a potential point of integration between the workflow enactment service and other infrastructure or application components.
Copyright 1993, 1994, 1995 Workflow Management Coalition Page 8 of 8
Fig 2 - Distribution within the workflow enactment service
The flow of work may involve the transfer of tasks between different vendors workflow products to enable different parts of the business process to be enacted on different platforms or sub-networks using particular products suited to that stage of the process. In this scenario the flow within the central box passes between two or more workflow products - for example activities 1,2 and 5 may be executed by one workflow system and activities 3 and 4 by a different system, with control passed between them at appropriate points within the overall workflow. Standards to support this transfer of workflow control enable the development of composite workflow applications using several different workflow products operating together as a single logical entity.
The full range of interfaces being defined by the WFM Coalition therefore covers:
. specifications for process definition data and its interchange
. interfaces to support interoperability between different workflow systems
. interfaces to support interaction with a variety of IT application types
. interfaces to support interaction with user interface desktop functions
. interfaces to provide system monitoring and metric functions to facilitate the management of composite workflow application environments
These are further developed in Section 3.