工程項目的系統(tǒng)分析

1、工程項目的系統(tǒng)分析工程項目的系統(tǒng)分析System Approach1. 系統(tǒng)的定義與基本概念系統(tǒng)的定義與基本概念 A set of interrelated and interdependent parts arranged in a manner that produces a unified whole. 系統(tǒng)是由相互作用和相互依賴的若干組成部分系統(tǒng)是由相互作用和相互依賴的若干組成部分(要素要素)結(jié)合而成的、具有特定功能的有機(jī)整體。結(jié)合而成的、具有特定功能的有機(jī)整體。 系統(tǒng)必須由兩個以上的要素組成系統(tǒng)必須由兩個以上的要素組成 要素與要素之間存在著一定的有機(jī)聯(lián)系要素與要素之間存在著一定的有機(jī)

2、聯(lián)系 任何系統(tǒng)都有特定的功能任何系統(tǒng)都有特定的功能Definition of systemAn organized or complex whole; an assemblage of things or parts interacting in a coordinated way.Besides being an “assemblage of parts ”, the definition of system should include three other features: Parts of the system are affected by being the system an

3、d are changed if they leave it; The assemblage of parts does something; The assemblage is of particular interest.The first feature means that, in systems, the whole is more than the sum of the parts. The name given to a way of viewing things in terms of their “wholeness”, or the whole being more tha

4、n the sum of the parts, is holism. Holism is the opposite of reductionism, which says that the things can be understood by simply breaking them down and understanding the pieces.The second feature of systems is that they are dynamic and exhibit some kind of behavior; they do something. The kind of b

5、ehavior they exhibit depends upon the particular kind of system at hand. System behavior can usually be observed in the outputs of the system or the way the system converts inputs to outputs, though the conversion process and the outputs may be quite obscure.Third, systems are conceived by the peopl

6、e looking at them, which means they exist in the eye (or mind) of the beholder. This is not to say that they fail to exist unless someone is there to see them, but rather that the conception of a system can be altered to suit ones purpose.2、系統(tǒng)的基本概念、系統(tǒng)的基本概念 Elements and subsystemsThe smallest part of

7、 a system is an element.A subsystem is a system that functions as a component of a larger system. When it is unnecessary to understand or reveal its inner workings, a subsystem can simply be thought of as an element. AttributesSystems, subsystems, and elements all have distinguishing characteristics

8、 and properties. These attributes describe or express the condition of systems, subsystems and elements in qualitative or quantitative terms. Environment and boundaryThe term environment is used to refer to anything that lies beyond the decision makers control yet influences the behavior or outcome

9、of the system.A system is separated from its environment by a boundary. ObjectivesHuman-made systems are designed to do something. They have objectives that conceived by people. One of the greatest aids for conceptualizing, creating, or investigating a system is to begin with a clear, concise statem

10、ent of the system objectives. Frequently objectives are broken down into a hierarchy of objectives. System structureElements and subsystems are linked together by relationships. The form taken by the relationships is referred to as the structure of the system.Most systems, including projects, can be

11、 conceptualized as both hierarchical and network systems. Inputs, process, outputsHuman-made systems accomplish things by converting inputs into outputs through a well-defined process.The system input that originates from the system itself is called feedback.InputsProcessOutputsFeedback Open & c

12、losed systemsIn contrast to machines, biological and social systems are not closed. They are open systems, which means they interact with the environment and have the capability to adapt to environment as well.Constraints and conflictsSystems have constraints or limitations imposed both from within

13、and by the environment, which may inhibit their ability to reach objectives.In human organizations, and especially in projects, the objectives of subsystems are frequently in conflict. IntegrationA systems elements and subsystems must perform in a synergistic fashion. All of the elements, the “assem

14、blage of parts”, must work in unison.Designing, implementing, and operating a system that adapts to changing environmental requirements and achieves effective, coordinated(so-called seamless) functioning of its elements and subsystems is called systems integration.系統(tǒng)工程方法論系統(tǒng)工程方法論 系統(tǒng)工程的方法論，是指運用系統(tǒng)工程研究問

15、題系統(tǒng)工程的方法論，是指運用系統(tǒng)工程研究問題的一套程序化方法，也就是為了達(dá)到系統(tǒng)的預(yù)期目的一套程序化方法，也就是為了達(dá)到系統(tǒng)的預(yù)期目標(biāo)，運用系統(tǒng)工程思想及技術(shù)內(nèi)容，解決問題的工標(biāo)，運用系統(tǒng)工程思想及技術(shù)內(nèi)容，解決問題的工作步驟。作步驟。 系統(tǒng)工程方法論的特點是，從系統(tǒng)工程方法論的特點是，從系統(tǒng)思想和觀點系統(tǒng)思想和觀點出發(fā)，將系統(tǒng)工程所要解決的問題放在系統(tǒng)的形式出發(fā)，將系統(tǒng)工程所要解決的問題放在系統(tǒng)的形式中加以考察，始終圍繞著系統(tǒng)的中加以考察，始終圍繞著系統(tǒng)的預(yù)期目的預(yù)期目的，從整體，從整體與部分、部分與部分和整體與外部環(huán)境的相互聯(lián)系、與部分、部分與部分和整體與外部環(huán)境的相互聯(lián)系、相互作用、相互

16、矛盾、相互制約的關(guān)系中綜合地考相互作用、相互矛盾、相互制約的關(guān)系中綜合地考察對象，以達(dá)到察對象，以達(dá)到最優(yōu)地處理問題最優(yōu)地處理問題的效果。的效果。系統(tǒng)工程方法論的基本原則系統(tǒng)工程方法論的基本原則 系統(tǒng)整體性原則系統(tǒng)整體性原則 系統(tǒng)工程方法論要求把研究對象（任務(wù)、項目）系統(tǒng)工程方法論要求把研究對象（任務(wù)、項目）都看成由不同部分構(gòu)成的有機(jī)整體，把全局觀點、都看成由不同部分構(gòu)成的有機(jī)整體，把全局觀點、整體觀點貫徹于整個項目（任務(wù)）的各個方面、各整體觀點貫徹于整個項目（任務(wù)）的各個方面、各個部分、各個階段，從整體上搞好局部的協(xié)調(diào)。個部分、各個階段，從整體上搞好局部的協(xié)調(diào)。 系統(tǒng)有序相關(guān)原則系統(tǒng)有序相關(guān)

17、原則 系統(tǒng)的有序性，是系統(tǒng)有機(jī)聯(lián)系的反映，系統(tǒng)系統(tǒng)的有序性，是系統(tǒng)有機(jī)聯(lián)系的反映，系統(tǒng)的任何聯(lián)系都是按一定等級和層次進(jìn)行的，都是秩的任何聯(lián)系都是按一定等級和層次進(jìn)行的，都是秩序井然、有條不紊的。在系統(tǒng)層次上表現(xiàn)出來的整序井然、有條不紊的。在系統(tǒng)層次上表現(xiàn)出來的整體特性是由要素或分系統(tǒng)層次相互關(guān)聯(lián)、相互制約體特性是由要素或分系統(tǒng)層次相互關(guān)聯(lián)、相互制約所形成的。所形成的。 系統(tǒng)目標(biāo)優(yōu)化原則系統(tǒng)目標(biāo)優(yōu)化原則 最優(yōu)化的概念貫穿于系統(tǒng)工程的始終，它是系最優(yōu)化的概念貫穿于系統(tǒng)工程的始終，它是系統(tǒng)工程的指導(dǎo)思想和追求目標(biāo)。在系統(tǒng)工程中普遍統(tǒng)工程的指導(dǎo)思想和追求目標(biāo)。在系統(tǒng)工程中普遍運用最優(yōu)化原則，就能使系統(tǒng)

18、取得滿意效果和最佳運用最優(yōu)化原則，就能使系統(tǒng)取得滿意效果和最佳效益。效益。 系統(tǒng)動態(tài)性原則系統(tǒng)動態(tài)性原則 研究對象內(nèi)部復(fù)雜的相互作用和外部的環(huán)境研究對象內(nèi)部復(fù)雜的相互作用和外部的環(huán)境多變性，使呈現(xiàn)出系統(tǒng)工程本身動態(tài)特性。因此，多變性，使呈現(xiàn)出系統(tǒng)工程本身動態(tài)特性。因此，應(yīng)把實施對象看做一個動態(tài)過程，分析系統(tǒng)內(nèi)外的應(yīng)把實施對象看做一個動態(tài)過程，分析系統(tǒng)內(nèi)外的各種變化，掌握變化的性質(zhì)、方向和趨勢，采取相各種變化，掌握變化的性質(zhì)、方向和趨勢，采取相應(yīng)的措施和手段，改進(jìn)工作方法，調(diào)整規(guī)劃和計劃，應(yīng)的措施和手段，改進(jìn)工作方法，調(diào)整規(guī)劃和計劃，在動態(tài)變化中求得系統(tǒng)的整體優(yōu)化。在動態(tài)變化中求得系統(tǒng)的整體優(yōu)化

19、。 系統(tǒng)分解綜合原則系統(tǒng)分解綜合原則 分解是將具有比較密切相關(guān)的關(guān)系要素進(jìn)行分分解是將具有比較密切相關(guān)的關(guān)系要素進(jìn)行分組，對系統(tǒng)來說就是歸納出相對對立、層次不同的組，對系統(tǒng)來說就是歸納出相對對立、層次不同的分系統(tǒng)；綜合則是完成新系統(tǒng)的籌建過程，即選擇分系統(tǒng)；綜合則是完成新系統(tǒng)的籌建過程，即選擇具有性能好、適用性強的分系統(tǒng)，設(shè)計出它們的相具有性能好、適用性強的分系統(tǒng)，設(shè)計出它們的相互關(guān)系，形成具有更廣泛價值的系統(tǒng)，以達(dá)到預(yù)定互關(guān)系，形成具有更廣泛價值的系統(tǒng)，以達(dá)到預(yù)定的目的。的目的。 系統(tǒng)創(chuàng)造性思維原則系統(tǒng)創(chuàng)造性思維原則 把陌生的事物看成是熟悉的東西，用已有的知把陌生的事物看成是熟悉的東西，用已

20、有的知識加以辨識和解決；把熟悉的事物看成是陌生的東識加以辨識和解決；把熟悉的事物看成是陌生的東西，用新的方法、新的原理加以研究，從而創(chuàng)造出西，用新的方法、新的原理加以研究，從而創(chuàng)造出新的理論、新的技術(shù)。新的理論、新的技術(shù)。Three common ways of applying the systems approach, called “system methodologies”, are systems analysis, systems engineering, and systems management. Each has a different purpose and scope,

21、 but all share a similar, systems view of the world.Systems approachAn appreciation of the systems approach is important for project managers because it is the approach that underlines the process of project management. Especially in technical projects, many of the steps and procedures are prescribe

22、d according to systems methodologies. Throughout projects there is often a need to apply a problem-solving approach called “systems analysis”; in large-scale engineering and developmental projects, the approach followed is called “systems engineering”; and most large projects are managed as systems,

23、 a process called “systems management”.No problem can be solved in isolation. Every problem is inextricably united to the environment, and attempts to solve it may cause other, more intractable problems. Churchman calls this the “environmental fallacy.”Examples abound of situations where solutions f

24、or the parts have led to worse problems for the whole.The systems approach tries to avoid the environmental fallacy. Systems analysisSystems analysis is a problem-solving framework to help decision makers select the best alternatives. By one definition, “systems analysis is a systematic examination

25、of a problem in which each step of the analysis is made explicit. Consequently, it is the opposite of a manner of reaching decisions which is largely intuitive, unsystematic, and where much of the argument remains hidden in the mind of the decision maker or his advisor. ” Thus, what distinguishes sy

26、stems analysis from other forms of analysis is the precision in defining the elements of the analysis.Process of conducting a systems analysisDecision makerProblem formulationObjectivesCriteriaResources/constraintsAlternativesAnalysis modelRedo systems analysisReject alternativesAccept alternative(s

27、)FormulationResearchAnalysis/judgmentVerification Elements of systems analysis Objective(s). The first task in systems analysis is to identify the decision makers and what they expect after the problem has been solved. This expectation is the objective. Objectives must be clear, concise, andideallym

28、easurable. To eliminate confusion and misunderstanding about the problem or system, both the decision maker and the systems analyst must agree to the objectives. Criteria. Criteria are performance measures that will enable the analyst to determine the extent to which objectives are being achieved. T

29、hey are the basis for ranking the performance of alternative solutions or courses of action to the problem. In projects, the criteria are referred to as requirements and specifications. Alternatives. Alternatives are potential solutions to problems and courses of action for attaining objectives. The

30、 common error in many analyses is to focus on the familiar alternatives and ignore innovative solutions. Ideally, a wide range of alternative solutions are considered. Resources and constraints. Resources are elements of the systemlabor, time, capital, materialsavailable to solve the problem. Constr

31、aints are elements of the system or environment that restrict the applicability or usefulness of alternatives. Resources and constraints determine what is feasible and reduce the number of potential solutions to a problem. Analysis model. The model incorporates all of the above elements so that cons

32、equences of all alternatives can be compared in terms of attainment of objectives.In doing systems analysis, one must be careful not to catch “modelism”in other words, not become more interested in the model than in the real world. Modelism leads to the study of irrelevant or over-idealized question

33、s rather than answers to important questions.Systems engineeringSystems engineering has been defined as “the science of designing complex systems in their totality to insure that the component subsystems making up the system are designed, fitted together, checked and operated in the most efficient w

34、ay.”Up through World War II, the term “systems engineering” referred to integrating existing components into a final product. Today it emphasizes instead the conception, design, and development of complex systems where the components themselves must be designed and developed from scratch and integra

35、ted together to fulfill mission objectives.In contrast to systems analysis, which focuses on decisions about a system, systems engineering is a way to actually bring a system into being.SystemConceptSystem Definition/Preliminary DesignDetailed Design/System DevelopmentSystems EvaluationConstruction/

36、ProductionSystem Operation/SupportSystems EvaluationSystem Phase-outSystems Engineering Process Stages of systems engineering System concept. Clarify the problem, establish the need and value for the system; set overall mission, objectives, and operational and maintenance requirements for the system

37、. System definition and preliminary design. Determine major functions of the system; cluster functions to form subsystems; perform systems analysis to evaluate design alternatives; prepare design specifications. Detailed design and development. Describe in detail subsystems, units, assemblies; devel

38、op models to test performance and integration of design; prepare for production of systemSystem production or fabrication. Maintain construction/production operation and produce the system;prepare for installation of system. System operation and support. Check out and install system within the user

39、environment; provide maintenance, field support, and system enhancement as necessary to ensure continued compliance with objectives; phase out system at the end of its useful life.A third application of the systems approach is systems management, the management and operation of organizations as syst

40、ems. Three major characteristics distinguish systems management. Systems managementFirst, it is total-system oriented and emphasizes achievement of the overall system mission and system objectives. Second, it emphasizes decisions that optimize the overall system rather than subsystems. Third, it is

41、responsibility-oriented. The manager of each subsystem is given specific assignments so that inputs, outputs, and contribution to total system effectiveness can be measured. Systems management works to ensure that organizations, responsibilities, knowledge, and data are integrated toward achieving o

42、verall objectives. Thus, the orientation of the systems manager is to consider the interactions and interdependencies between various subsystems and with the environment.The relationships between systems management, systems analysis, and systems engineering can be explained in terms of when they are

43、 applied during the life cycle of a system.Systems management performs the basic managerial functions of planning, organization, and control throughout the life of a system, but the focus remains on coordinating and integrating work rather than actually performing it.Systems management often works p

44、arallel with systems engineering and utilizes the tools of systems analysis. The purpose of systems analysis is to ask questions about the goal or mission of the system, the kind and nature of resources to use, and the organization of people and facilities. In systems management, systems analysis is

45、 used to plan and control activities and materials, and to evaluate system operation to determine when and why the system is not functioning properly.Systems management entails identification of total system requirements, control over the evolution of requirements and design, integration of technica

46、l efforts, and development of data and documentation. It is applied over the full life cycle of the system (systems development management; systems operations management)Systems analysisSystems managementSystems engineeringConcept-design-fabricationDevelopmentOperationSystem Life CyclePrimary activi

47、tySecondary or as needed activityA. D. Hall的的“三維結(jié)構(gòu)體系三維結(jié)構(gòu)體系”知識維知識維時間維時間維邏輯維邏輯維社會科學(xué)社會科學(xué)工程技術(shù)工程技術(shù)法律法律明確問題明確問題 系統(tǒng)指標(biāo)設(shè)計系統(tǒng)指標(biāo)設(shè)計系統(tǒng)方案綜合系統(tǒng)方案綜合 系統(tǒng)分析系統(tǒng)分析 方案選擇方案選擇 方案決定方案決定 實施計劃實施計劃規(guī)劃階段規(guī)劃階段擬定方案階段擬定方案階段系統(tǒng)研制階段系統(tǒng)研制階段生產(chǎn)階段生產(chǎn)階段裝配階段裝配階段運行階段運行階段更新階段更新階段系統(tǒng)工程活動矩陣系統(tǒng)工程活動矩陣時間維邏輯維時間維邏輯維P. Checkland的軟系統(tǒng)方法論的軟系統(tǒng)方法論問題現(xiàn)狀說明問題現(xiàn)狀說明(無結(jié)構(gòu)

48、問題無結(jié)構(gòu)問題)搞清問題的關(guān)搞清問題的關(guān)聯(lián)因素聯(lián)因素說明現(xiàn)狀說明現(xiàn)狀,目的是為了改善現(xiàn)狀目的是為了改善現(xiàn)狀,弄清問題弄清問題本身的基本定義本身的基本定義搞清楚與改善有關(guān)的各種因素及因素間搞清楚與改善有關(guān)的各種因素及因素間的相互關(guān)系的相互關(guān)系概念模型概念模型比較比較實施實施運用系統(tǒng)觀點和系統(tǒng)思考描述系統(tǒng)活動的運用系統(tǒng)觀點和系統(tǒng)思考描述系統(tǒng)活動的現(xiàn)狀現(xiàn)狀,可用結(jié)構(gòu)模型和有流向的框圖表達(dá)可用結(jié)構(gòu)模型和有流向的框圖表達(dá)根據(jù)數(shù)學(xué)模型的理論和方法根據(jù)數(shù)學(xué)模型的理論和方法,改進(jìn)上述概念改進(jìn)上述概念模型模型,然后將概念模型和現(xiàn)狀進(jìn)行比較然后將概念模型和現(xiàn)狀進(jìn)行比較,逐逐步得出滿意的可行解步得出滿意的可行解對改善問題予以實施對改善問題予以實施Project breakdown determines what is referred to as a projects work breakdown structure (WBS), which is basically a breakdown of the whole project into component parts. The WBS is created as a logic hierarchical decomposition