《系统工程第一章》

1、系统工程第一章PPT课件1 Systems Engineering 系统工程 鄢萍 教授/博导 2021-4-29系统工程第一章PPT课件2 nCourse Name: Systems Engineering nCourse Hours and Credits: 30 Hs, 2Scrs nTextbook: nIntroduction to System Engineering Andre P. Sage George Mason University nIntroduction to Operation Research, Seventh Edition, Prof. Hiller, St

2、anford University n系统工程教程：喻湘存，熊曙初，清华大学出版社 n系统工程，第三版，汪应洛，机械工业出版社 2021-4-29系统工程第一章PPT课件3 2021-4-29系统工程第一章PPT课件4 2021-4-29系统工程第一章PPT课件5 nTesting: nNormal Testing, but the answer should be written in English. 系统工程第一章PPT课件6 Chapter 1 Introduction to Systems Engineering 2021-4-29系统工程第一章PPT课件7 Introduction

3、 to Systems Engineering 1.1 THE SYSTEMS POINT OF VIEW 1.2 DEFINITIONS OF SYSTEMS ENGINEERING 1.3 HISTORY OF TECHNOLOGICAL DEVELOPMENT 1.4 SYSTEMS ENGINEERING KNOWLEDGE 1.5 The APPLICATION OF SYSTEMS ENGINEERING 2021-4-29系统工程第一章PPT课件8 1.1 THE SYSTEMS POINT OF VIEW Because systems engineering is often

4、 described as a new way of thinking, we need to describe what we mean by the systems point of view. This will lead us to see that it is not really new. The systems perspective takes a big picture or holistic, or gestalt, view of large-scale problems and their proposed technological solutions. 2021-4

5、-29系统工程第一章PPT课件9 1.1 THE SYSTEMS POINT OF VIEW This means that systems engineers not only examine the specifics(细节细节) of the problem under consideration but also investigate relevant factors in the surrounding environment. They realize that problems are embedded in a situation or environment that ca

6、n have significant impacts on the problem and its proposed alternative solutions. This is not to say that systems engineers do not get very detailed or specific far from it. There is also much effort devoted to in scoping, high-fidelity modeling, and specification of system requirements and architec

7、ture. 2021-4-29系统工程第一章PPT课件10 1.1 THE SYSTEMS POINT OF VIEW The systems viewpoint stresses（讲述了）（讲述了） that there usually is not a single correct answer or solution to a large-scale problem or design issue. Instead, there are many different alternatives （可选方案）（可选方案） that can be developed and implement

8、ed depending on the objectives （目标）（目标） the system is to serve and the values of the people and organizations with a stake in the solution. Lets add more detail to what we mean by the systems point of view. 2021-4-29系统工程第一章PPT课件11 1.1 THE SYSTEMS POINT OF VIEW First, a system is defined as a group o

9、f components that work together for a specified purpose. This is a very simple but correct definition. Purposeful action is a basic characteristic of a system. A number of functions must be implemented in order to achieve these purposes. This means that systems have functions. They are designed to d

10、o specific tasks. 2021-4-29系统工程第一章PPT课件12 1.1 THE SYSTEMS POINT OF VIEW Systems are often classified（分类） by their ultimate purpose: service-oriented systems, product-oriented systems, or process-oriented systems. nAn airport can be viewed as an example of a service system. The planes, pilots, mechan

11、ics, ticket agents, runways, and concourses are all components that work together to provide transport service to passengers and freight. nAn automobile assembly plant is an example of a product- oriented system. The raw materials, people, and machines all work together to produce a finished car. nA

12、 refinery that changes crude oil into gasoline is an example of a process-oriented system. 2021-4-29系统工程第一章PPT课件13 1.1 THE SYSTEMS POINT OF VIEW We note here that the systems considered by systems engineers may be service systems, or they may be product systems. The systems may be systems designed f

13、or use by an individual or by groups of individuals. These systems may be private sector systems, or they may be government or public sector systems. 2021-4-29系统工程第一章PPT课件14 1.1 THE SYSTEMS POINT OF VIEW For Example, An overhead projector（高射投影仪） may be viewed as a system. So may the combination of a

14、n overhead projector, a screen on which it projects, and a set of overheads. The instructor using the overhead may also be included in the notion of system. From another perspective, the combination of the overhead, screen, overheads, instructor, and students may be regarded as a system.“ Thus, when

15、 we use a term such as engineer a system, we must be very careful to define the nature of the system that we wish to engineer and what is included in. and exempted from, the notion of system. We must also be very concerned with the interfaces to the system that we are engineering. 2021-4-29系统工程第一章PP

16、T课件15 1.1 THE SYSTEMS POINT OF VIEW The systems point of view also recognizes that a problem and its solution have many elements or components, and there are many different relations among them. The important aspects of a problem are often a function of how the components interact. Simple aggregatio

17、n of individual aspects of a problem is intuitively appealing but often wrong. The whole is often not simply the sum of its parts. Often, much more is involved. This does not suggest at all that scientific analysis, in which an issue is disaggregated into a number of component issues and understandi

18、ng sought of the individual issues, is in any way improper. 2021-4-29系统工程第一章PPT课件16 1.1 THE SYSTEMS POINT OF VIEW The following steps are essential in finding solutions to large and complicated problems: nDesegregation or decomposition（分解） of a large issue into smaller, more easily understandable pa

19、rts nAnalysis of the resulting large number of individual issues nAggregation of the results to attempt to find a solution to the major issue This is the essence of the formal scientific method. 2021-4-29系统工程第一章PPT课件17 1.1 THE SYSTEMS POINT OF VIEW However, interpretation must follow analysis, and m

20、eaningful issue formulation must precede it. Also, these formal efforts need to be conducted across a variety of life-cycle phases. The systems approach attempts to incorporate all of these. 2021-4-29系统工程第一章PPT课件18 1.1 THE SYSTEMS POINT OF VIEW System components are often of very different types; an

21、d it is helpful, from a systems perspective, to distinguish among them. Consider a university as a system for producing educated graduates. Some of the parts of the university system are structural or static components, such as university buildings. As the system is operating, these structural compo

22、nents usually do not change much. Operating components are dynamic and perform processing such as the professors in a university who teach students. Flow components are often material, energy, or information; but in this example, students are the parts that flow or matriculate through the university

23、 system. 2021-4-29系统工程第一章PPT课件19 1.1 THE SYSTEMS POINT OF VIEW Again, how the components interact is an important aspect of any system, its problems or design issues, and their alternative solutions. For example, grades are one mechanism（机制） for interaction between professors and students. Grades se

24、rve a purpose, intended or not. it is important to understand what purpose, intended and unintended, they serve. 2021-4-29系统工程第一章PPT课件20 1.1.1Attributes Characterizing Systems Four Basic Attributes of the System From among many characteristics, four basic attributes which play basic roles to charact

25、erize the system are described in the following (Hitomi, 1971): (1) Assemblage（集合、装配）. A system consists of a plural number of distinguishable units (elements, components, factors, subsystems （子系统）, etc.), which may be physical or conceptual, natural or artificial. 2021-4-29系统工程第一章PPT课件21 (2) Relati

26、onship. Several units assembled together are merely a group or a set. For such a group to be admissible as a system, a relationship or an interaction must exist among the units. 1.1.1Four Basic Attributes of the System 2021-4-29系统工程第一章PPT课件22 EXAMPLE 1.1 nLogical relationship is determined essential

27、ly by definitions and assumptions, such as the relation of production, inventory, and sales in a period: Final inventory（最后清单） = initial inventory + production quantity（生产数量） - sales quantity. EXAMPLE 1.2 nInstitutional relationship（体制关系） is specified （规定，指定） by social institution, laws, and regulat

28、ions, such as： tax amount （税额）= profit (or income) tax rate. 1.1.1Four Basic Attributes of the System 2021-4-29系统工程第一章PPT课件23 1.1.1Four Basic Attributes of the System (3) Goal-seeking. An actual system as a whole performs a certain function or aims at single or multiple objectives. Wherever these ob

29、jectives are attained at their maximum/minimum levels, system optimization is said to have been performed. For this purpose it is necessary to be able to measure, objectively or subjectively, the degree of attainment of the objectives. An objective that is measurable by any means is called a goal/ta

30、rget. 2021-4-29系统工程第一章PPT课件24 EXAMPLE 1.3 A manufacturing system effectively converts resources of production into produced goods (products), attaining an objective that creates high utilities by adding values to the raw materials, resulting in superior quality, cost and delivery. 2021-4-29系统工程第一章PP

31、T课件25 EXAMPLE 1.4 nA business management system coordinates functional divisions-production, sales personnel and finance, which constitutes the system-and allocates limited resources available to those divisions. This system aims at organizational objectives such as profit maximization, reasonable r

32、ate of return on capital, increase in market share, stable growth, public services (philanthropy), etc. 2021-4-29系统工程第一章PPT课件26 1.1.1Four Basic Attributes of the System (4) Adaptability to environment. A specific, factual system behaves so as to adapt to the change in its surroundings, or external e

33、nvironment. This external environment influences and is influenced by the system, in that matter and/or energy and/or information are received from and given to each other. A system that is capable of controlling itself in such a way as to be always optimal even under changes in the external environ

34、ment, is called an adaptive (or cybernetic) system. 2021-4-29系统工程第一章PPT课件27 If this system possesses dynamic adaptability, approaching a desired state with the least time lag by changing its internal structure and functions as the environment changes, it is as self- organizing system. 2021-4-29系统工程第

35、一章PPT课件28 EXAMPLE 1.5 n Human is a complete adaptive system. EXAMPLE 1.6 n A business system is a self-organizing system, in that it generates a diversified variety of activities, resulting in economies of scope. 2021-4-29系统工程第一章PPT课件29 nA business system is an adaptive system, in that it makes prop

36、er decisions so as to achieve its objectives under severe environmental situations (competitors, markets, industrial societies, economic and political conditions, international trends, etc.). The system often reacts to its environment to make its future behavior more effective: e.g. it performs mark

37、eting activities, such as advertising and merchandising, to enhance potential demands in the market. 2021-4-29系统工程第一章PPT课件30 1.1.2 Systems Defined Four Definitions of Systems On the basis of the foregoing considerations, the four essential definitions of systems can now be given as follows (Hitomi,

38、1975). 2021-4-29系统工程第一章PPT课件31 1.1.2 Systems Defined (1) Abstract (or basic) definition. On the basis of the first two attributes above, a system is a collection of recognizable units having relationships among the units. Under this definition, general system theory has been developed, wherein thing

39、s are deliberated theoretically, logically, and speculatively. 2021-4-29系统工程第一章PPT课件32 1.1.2 Systems Defined (2) Structural (or static) definition. On the basis of all four attributes, a system is a collection of recognizable units having relationships among the units, aiming at specified single or

40、multiple objectives subject to its external environment. 2021-4-29系统工程第一章PPT课件33 1.1.2 Systems Defined n(3) Transformational (or functional) definition. From the last attribute, the effects of the environment upon the system are inputs (including unforeseen disturbances), and, conversely, the effect

41、s in which the system influences the environment are outputs. From this consideration ，a system receives inputs from its environment, transforms them to outputs, and releases the outputs to the environment, whilst seeking to maximize the productivity of the transformation. 2021-4-29系统工程第一章PPT课件34 1.

42、1.2 Systems Defined (4) Procedural (or dynamic) definition. The process of transformation in the input-output system consists of a number of related stages, at each of which a specified operation is carried out. By performing a complete set of operations according to the precedence relationship on t

43、he stages, a function or task is accomplished. Thus, a system is a procedure-a series of chronological, logical steps by which all repetitive tasks are performed. 2021-4-29系统工程第一章PPT课件35 1.1.3 System Life Cycles A very important fundamental concept of systems engineering is that all systems are asso

44、ciated with life cycles. Similar to natural systems that exhibit a birth-growth-aging and death life cycle, human-made systems also have a life cycle. Most generally, this life cycle consists of definition of the requirements for a system, development of the system itself, and deployment of the syst

45、em in an operating environment. These three essential life-cycle phases are always needed. Each of them may be described in terms of a larger number of more fine-grained phases. In all types of system evolution, and as we will discuss, there will be a minimum of three phases: nDefinition nDevelopmen

46、t nDeployment 2021-4-29系统工程第一章PPT课件36 1.1.3 System Life Cycles These comprise the essential systems engineering process activities. This life-cycle perspective should also be associated with a long-term view toward planning for system evolution, research to bring about any new and emerging technolog

47、ies needed for this evolution, and a number of activities associated with actual system evolution, or acquisition. 2021-4-29系统工程第一章PPT课件37 1.1.3 System Life Cycles Thus, we see that the efforts involved in the life-cycle phases for definition, development, and deployment need to be implemented acros

48、s three life cycles that comprise: nSystems planning and marketing, nResearch, development, test, and evaluation (RDT n individualized and personalized systems of interactive instruction; n individualized design of aids to the disabled and handicapped; nprediction and planning in business, agricultu

49、re, health, and education; nsupport to knowledge workers in a number of new and classic enterprises. Most of these involve the integration of the information technologies of computers and communications through use of systems engineering approaches for the development of processes and products. This

50、 has led to a fundamental change in the way in which systems engineering is accomplished. Some now call the field computer-aided systems engineering 2021-4-29系统工程第一章PPT课件62 1.3 HISTORY OF TECHNOLOGICAL DEVELOPMENT Thus, we see that the physical and material science basis for engineering and technolo

51、gy is now augmented by an information science basis made possible primarily through the development of the modern microprocessor and associated computers. 2021-4-29系统工程第一章PPT课件63 Introduction to Systems Engineering 1.1 THE SYSTEMS POINT OF VIEW 1.2 DEFINITIONS OF SYSTEMS ENGINEERING 1.3 HISTORY OF T

52、ECHNOLOGICAL DEVELOPMENT 1.4 SYSTEMS ENGINEERING KNOWLEDGE 1.5 THE APPLICATION OF SYSTEMS ENGINEERING 2021-4-29系统工程第一章PPT课件64 1.4 SYSTEMS ENGINEERING KNOWLEDGE Figure 1.8 illustrates that systems engineering knowledge is comprised of the following: nKnowledge principles, which generally represent fo

53、rmal problem solving approaches to knowledge, generally employed in new situations and/or unstructured environments nKnowledge practices, which represent the accumulated wisdom and experiences that have led to the development of standard operating policies for well-structured problems nKnowledge per

54、spectives, which represent the view that is held relative to future directions and realities in the technological area under consideration 2021-4-29系统工程第一章PPT课件65 1.4 SYSTEMS ENGINEERING KNOWLEDGE 2021-4-29系统工程第一章PPT课件66 1.4 SYSTEMS ENGINEERING KNOWLEDGE Knowledge principles include a host of scient

55、ific theories. In a sense, these represent the why associated with the functioning of systems. For example, one knowledge principle is that associated with Newtons law. It suggests that force is equal to mass times acceleration and that because acceleration is the derivative of velocity and velocity

56、 is the derivative of position, we have now. What we have here is a simple model of one-dimensional motion. 2021-4-29系统工程第一章PPT课件67 1.4 SYSTEMS ENGINEERING KNOWLEDGE We could continue to extrapolate on this model of motion, based on Newtons law of mechanics, until we actually come up with a differen

57、tial equation, doubtlessly a very complicated one, that could be used to predict the motion of an automobile when subjected to various forcing functions due to different time histories of accelerator pedal movement and braking controls. Then we could use this differential equation to project the tim

58、e that would be required to stop a fancy sports car traveling at 60 miles per hour under a certain type of braking action. We would be using knowledge principles to predict the braking effectiveness of this particular car. 2021-4-29系统工程第一章PPT课件68 1.4 SYSTEMS ENGINEERING KNOWLEDGE Alternately, we cou

59、ld develop a set of knowledge practices that are based on actual experimental observations of different drivers breaking different cars. Then we could publish such a table. The table might be adopted as a standard, and any particular car that could not stop in the distance specified by the standard

60、might well be subjected to an appropriate repair effort. While the table might have its basis in the physical differential equations for an automobile, there would not necessarily be any reference to these knowledge principles in obtaining the table. The knowledge principles associated with vehicle