系统工程第七章.ppt

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1、重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERINGChapter 7Chapter 7 A New Systems Engineering(NSE)(2009)(2009)重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING Classic system

2、s engineering strongly emphasizes the initial phases of modeling,research,analysis,whole system design and specification,partitioning,sub-system design and specification and so on.It contains a careful planning,systematic ethic.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教

3、授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING7.1 Closed systems Philosophy Classic systems engineering has developed as a closed systems philosophy.because of the standard practice of producing a fixed,defined system against a customers requirement.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长

4、 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING To systems engineers this may seem wholly admirable,but consider:The customer who drew up(草拟)the requirement may be expert in terms of his or her needs and objectives,without being expert in understanding systems and their(exceedingly complex)

5、interactions The requirement addressed a particular situation at a particular time,neither likely to be relevant by the time the system has been implemented and delivered The requirement addresses some technologically based solution to a problem which is almost invariably human-centred Users involve

6、d in specifying the requirement represented their own viewpoint these users will probably have been replaced by different users with different viewpoints by the time of delivery The delivered system changes both the operational environment and the other systems with which it interacts in that enviro

7、nment.In consequence,the new system changes the situation and rules which existed prior to its arrival,generally rendering the original requirement specification wrong重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING So,systems engineeri

8、ng is essentially an open system and the systems it provides for customers are essentially open,too.It is the unfortunate inheritance of systems engineering from conventional hard engineering and from much of classical science that inhibits(抑抑制制)an open systems attitude.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重

9、庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING For large-scale and complex systems，it is imprudent to meet a customers requirement blindly,for many reasons:Major corporate investment in implementing the customers requirement may be necessary yet ill-advised.Often

10、 the thrill of the competitive chase for a major system contract can blind systems practitioners（从业者）to the investment risk while at the same time driving down the price and delivery time to beat the competition.Companies can become heavily committed to one or two such systems projects;failure of th

11、ese can ruin the company concerned.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING The customer may specify requirements poorlycustomers do,very regularlyand simply meeting their requirement precisely but blindly may not provide them w

12、ith what they want or need(often not the same thing).That the company provided the customer with what was specified will be forgotten;that the company produced an successful system will be remembered.The customers requirement may result in a system which will damage the environment,squander（浪费）（浪费）s

13、carce resources,endanger populations.In other words,social and ethical questions cannot be ruled out（排除）.Engineers generally consider such questions to be dangerous,of course,and to be avoided,but as our systems become larger,more interwoven（交织、混杂）and complex,the opportunity to avoid consequences di

14、minishes.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING7.2 Open systems Philosophy Open systems continually interchange energy,substance and information with other systems.They catabolize（使发生分解）and anabolize（使合成代谢）breakdown and build

15、upinternally,using interflows with other systems to acquire and dispose of energy,substance and information.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING All systems are open,saving perhaps the Universe itself.A systems engineering g

16、roup within a company is an open system:it interchanges people,skills,tools,techniques and ideas with other systems;it can change its size,reduce its entropy and do all the other things that open systems can do that closed systems supposedly cannot.The systems provided by systems engineers are open

17、systems too.First and foremost they are open to their users to such a degree that users and technology may not be sensibly separable.The combination of user and technology,as a single system,is open to the environment and the sibling systems it contains.The user/technology system will adapt as the s

18、ibling interactions and their environment change.And it is principally for this reason that classic systems engineering failsit concentrates on producing a fixed technological solution to a continually moving problem.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博

19、导博导博导2009 SYSTEMS ENGINEERING7.3 DESIGNING OPEN SYSTEMS 1.avoid Carefully-Specified Obsolescence（荒废、退化）（荒废、退化）How can open systems be designed and implemented successfully in a fixed price environment?The essence of the difficulty facing systems engineers today is that of providing a fixed solution

20、against a fixed specification.This is taken to mean that everything must be specified in ever-increasing detail,so that the supplier can prove it has been supplied and the customer can be sure it is what was required.Specification in ever-increasing detail takes longer and longer,increasing the time

21、 delay between emergence of the need and provision of the solution;the greater the delay,the more obsolescent the system when finally introduced.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING Principal amongst the characteristics of o

22、pen systems are the ability to:Adapt to changing environments Modify function and structure Adapt interflows with other systems Adapt intraflows within the system,between its internal partitions Absorb chunks of negative entropy to use internally(as animals absorb proteins and use it to build themse

23、lves)for changes in structure,capability,etc Grow and shrink without disrupting system operation Replace worn parts without disrupting system operation If we are to avoid carefully-specified obsolescence,the solution is clear;we must specify the adaptability of the system,rather than the simple stat

24、ic features of the system,as at present.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING 2 Specifying Adaptability Specifying adaptability may be easier than it appears.Consider a human activity system(HAS).The individuals are adaptable

25、 anywaywe humans are possibly the most adaptable creatures on Earth,It is the way we educate and organize ourselves and our technology that limits our flexibility and adaptability.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING What ca

26、n we do to make a group of humans adaptable?Add varietyinclude in the group various skills,ages,characters,capabilities Create an organization that constantly reviews itself to see if it could improve its contribution(to its containing system)Within that organization create,and continually rearrange

27、,teams which have variety and which compete with each other so that useful variety is differentially rewarded Avoid any one team becoming so dominant that team and individual variety are submerged.Dominance tends to be monotonal（单一）it can play only one note,and that is the opposite of adaptability I

28、ntroduce new variety to the team,or new teams,as the environment changes.Dispense with variety and capacity that clearly have no further relevance Network with other HASs which offer variety and which complement the HAS of interest.Combine teams across the network.Continually review that networking.

29、重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING So,how to specify technological adaptability.Consider a computer graphic display to be provided as part of an information decision-action(IDA)systema system for making decisions in real t

30、ime,operated by humans with decision support partly from technological devices.We could provide the graphic display in either of two ways:1 With all the necessary screen formats carefully analysed,designed using the best human factors principles,together with a specification for testing.2 As 1 but w

31、ith the addition of a screen formatter which enables the future user to adapt existing formats,or create entirely new ones,as the needs of the job,or his/her particular idiosyncrasies（喜好）dictate重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGIN

32、EERING Incorporating the screen formatter from the start costs little more,and perhaps even less since it may simplify development,prototyping,etc.What can be done for a graphics display can be done for most technological devices.It simply takes a change of perspectivea paradigm shift,to use the jar

33、gon（行话）.For example,we can design databases for adaptability and we can carefully specify that adaptability.In the future,we must become smarter.We cannot afford to go on replacing one rigid,short-lived system with another.It is expensive,wasteful of resources and gives poor,continually interrupted

34、performance.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING7.4 Design Guidelines of New Systems Engineering Consider the following simplified example:A new,fossil-fuel power station is to be introduced to an underdeveloped region suppo

35、rting a poor,largely agrarian（耕地的）（耕地的）society.Design a robust power system to contribute maximally to the region and to minimize any undesirable side effects.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING Step 1.Establish SOI Objecti

36、ves and Requirements by Reference to Containing System(s)The containing systems will include:The regional economy The regional society The regional ecology The regional energy system The objectives of the economic system might well include an increase in agricultural productivity(through mechanizati

37、on and cheaper fertilizers),and an increase in industrialization leading to wealth generation and a beneficial change in the balance of imports and exports.The objectives of the regional society would be to flourish,and to enhance the perceived quality of life by using the increase in electrical pow

38、er and wealth.The regional ecology could hardly be said to have objectives,since it is not a purposeful system.However,we may ascribe purpose to it.The objectives of the regional ecology are to maintain the variety and balance of flora and fauna,so maintaining the biosphere on which the region is fo

39、unded.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERINGPower generation intent structure重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING The objectives of the regional energ

40、y system would be to generate and distribute affordable power for the whole region,safely,cleanly,efficiently,continuously and sufficient to meet the developing need.Since these are the expectations from the new regional power-generation system,the measure of our system would be in its success in co

41、ntributing to all these objectivesnot simply those of generating power.As Figure 12.7 shows,the objectives can be networked,so presenting a structured mission,or Prime Directive,for the new regional power generation system,as follows:To contribute to a flourishing society with an improved quality of

42、 life for all the citizens in the region through the provision of safe,clean,affordable electrical power.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING Step 2.Identify(Sibling)Systems and their Interactions to be Perturbed by the SOI

43、Perturbed systems include almost all of those in the region,social,economic,ecological,transportation,etc.Fossil-fuel for the power station must be mined,causing an increase in population and infrastructure around the mining area(s),while some high-grade fuels may need to be imported.Mining creates

44、an ecological and a visual disturbance.The fossil-fuel will need to be transported over inadequate roads,so a transport system will need to be built,comprising new roads,fuel supplies,fuel dumps,garages,lorries,mechanics,drivers,loading bays,unloading bays,conveyers（运送装置）,chutes（斜道）,etc.,etc.Economi

45、c change will be evident in the investment in infrastructure and transportation systems,the training and hire of personnel,their relative affluence and consequent spending on essentials and luxury goods.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYST

46、EMS ENGINEERING Social strain can be foreseen between the new“haves”and the existing“have-nots”.The increase in power available within the region will reduce the cost of power,enabling new businesses to form and flourish,shifting the population pattern towards towns and cities for two reasons:increa

47、sed productivity on the farm will reduce labour needs;jobs will become available in the towns as businesses form,draw together for mutual self-reward and coalesce（联合、接合）.All of these represent disturbed sibling systems.重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博

48、导博导博导博导2009 SYSTEMS ENGINEERING Step 3.Conceive Complementary Systems as New/Modified Siblings to Neutralize（中和）（中和）Unwanted Perturbations Complementary systems will be required to:Absorb/reuse the waste/effluent/dissipation/spill from mining,transportation,power generation,distribution and utilizat

49、ion.Prevent any reduction in ecological variety(which can also be reduced by judicious(明智)choice of location for a power station in relation to mining areas and centres of power utilization).This might include moving species,ring-fencing sensitive areas,submerging infrastructure,etc.重庆大学制造工程研究所副所长重庆

50、大学制造工程研究所副所长重庆大学制造工程研究所副所长重庆大学制造工程研究所副所长 鄢萍鄢萍 博士博士博士博士 教授教授教授教授 博导博导博导博导2009 SYSTEMS ENGINEERING Manage the move of the regional economy such that increased agricultural mechanization and fertilizer production(objectives)are not impeded by lack of resources,resource wastage or misapplication,and tha