系统工程第七章

Chapter7ANewSystemsEngineering NSE 2009 Classicsystemsengineeringstronglyemphasizestheinitialphasesofmodeling research analysis wholesystemdesignandspecification partitioning sub systemdesignandspecificationandsoon Itcontainsacarefulplanning systematicethic 7 1ClosedsystemsPhilosophy Classicsystemsengineeringhasdevelopedasaclosedsystemsphilosophy becauseofthestandardpracticeofproducingafixed definedsystemagainstacustomer srequirement Tosystemsengineersthismayseemwhollyadmirable butconsider Thecustomerwhodrewup 草拟 therequirementmaybeexpertintermsofhisorherneedsandobjectives withoutbeingexpertinunderstandingsystemsandtheir exceedinglycomplex interactions Therequirementaddressedaparticularsituationataparticulartime neitherlikelytoberelevantbythetimethesystemhasbeenimplementedanddelivered Therequirementaddressessometechnologicallybasedsolutiontoaproblemwhichisalmostinvariablyhuman centred Usersinvolvedinspecifyingtherequirementrepresentedtheirownviewpoint theseuserswillprobablyhavebeenreplacedbydifferentuserswithdifferentviewpointsbythetimeofdelivery Thedeliveredsystemchangesboththeoperationalenvironmentandtheothersystemswithwhichitinteractsinthatenvironment Inconsequence thenewsystemchangesthesituationandruleswhichexistedpriortoitsarrival generallyrenderingtheoriginalrequirementspecificationwrong So systemsengineeringisessentiallyanopensystemandthesystemsitprovidesforcustomersareessentiallyopen too Itistheunfortunateinheritanceofsystemsengineeringfromconventionalhardengineeringandfrommuchofclassicalsciencethatinhibits 抑制 anopensystemsattitude Forlarge scaleandcomplexsystems itisimprudenttomeetacustomer srequirementblindly formanyreasons Majorcorporateinvestmentinimplementingthecustomer srequirementmaybenecessaryyetill advised Oftenthethrillofthecompetitivechaseforamajorsystemcontractcanblindsystemspractitioners 从业者 totheinvestmentriskwhileatthesametimedrivingdownthepriceanddeliverytimetobeatthecompetition Companiescanbecomeheavilycommittedtooneortwosuchsystemsprojects failureofthesecanruinthecompanyconcerned Thecustomermayspecifyrequirementspoorly customersdo veryregularly andsimplymeetingtheirrequirementpreciselybutblindlymaynotprovidethemwithwhattheywantorneed oftennotthesamething Thatthecompanyprovidedthecustomerwithwhatwasspecifiedwillbeforgotten thatthecompanyproducedansuccessfulsystemwillberemembered Thecustomer srequirementmayresultinasystemwhichwilldamagetheenvironment squander 浪费 scarceresources endangerpopulations Inotherwords socialandethicalquestionscannotberuledout 排除 Engineersgenerallyconsidersuchquestionstobedangerous ofcourse andtobeavoided butasoursystemsbecomelarger moreinterwoven 交织 混杂 andcomplex theopportunitytoavoidconsequencesdiminishes 7 2OpensystemsPhilosophy Opensystemscontinuallyinterchangeenergy substanceandinformationwithothersystems Theycatabolize 使发生分解 andanabolize 使合成代谢 breakdownandbuildup internally usinginterflowswithothersystemstoacquireanddisposeofenergy substanceandinformation Allsystemsareopen savingperhapstheUniverseitself Asystemsengineeringgroupwithinacompanyisanopensystem itinterchangespeople skills tools techniquesandideaswithothersystems itcanchangeitssize reduceitsentropyanddoalltheotherthingsthatopensystemscandothatclosedsystemssupposedlycannot Thesystemsprovidedbysystemsengineersareopensystemstoo Firstandforemosttheyareopentotheiruserstosuchadegreethatusersandtechnologymaynotbesensiblyseparable Thecombinationofuserandtechnology asasinglesystem isopentotheenvironmentandthesiblingsystemsitcontains Theuser technologysystemwilladaptasthesiblinginteractionsandtheirenvironmentchange Anditisprincipallyforthisreasonthatclassicsystemsengineeringfails itconcentratesonproducingafixedtechnologicalsolutiontoacontinuallymovingproblem 7 3DESIGNINGOPENSYSTEMS 1 avoidCarefully SpecifiedObsolescence 荒废 退化 Howcanopensystemsbedesignedandimplementedsuccessfullyinafixedpriceenvironment Theessenceofthedifficultyfacingsystemsengineerstodayisthatofprovidingafixedsolutionagainstafixedspecification Thisistakentomeanthateverythingmustbespecifiedinever increasingdetail sothatthesuppliercanproveithasbeensuppliedandthecustomercanbesureitiswhatwasrequired Specificationinever increasingdetailtakeslongerandlonger increasingthetimedelaybetweenemergenceoftheneedandprovisionofthesolution thegreaterthedelay themoreobsolescentthesystemwhenfinallyintroduced Principalamongstthecharacteristicsofopensystemsaretheabilityto Adapttochangingenvironments Modifyfunctionandstructure Adaptinterflowswithothersystems Adaptintraflowswithinthesystem betweenitsinternalpartitions Absorb chunksofnegativeentropytouseinternally asanimalsabsorbproteinsanduseittobuildthemselves forchangesinstructure capability etc Growandshrinkwithoutdisruptingsystemoperation ReplacewornpartswithoutdisruptingsystemoperationIfwearetoavoidcarefully specifiedobsolescence thesolutionisclear wemustspecifytheadaptabilityofthesystem ratherthanthesimplestaticfeaturesofthesystem asatpresent 2SpecifyingAdaptabilitySpecifyingadaptabilitymaybeeasierthanitappears Considerahumanactivitysystem HAS Theindividualsareadaptableanyway wehumansarepossiblythemostadaptablecreaturesonEarth Itisthewayweeducateandorganizeourselvesandourtechnologythatlimitsourflexibilityandadaptability Whatcanwedotomakeagroupofhumansadaptable Addvariety includeinthegroupvariousskills ages characters capabilities Createanorganizationthatconstantlyreviewsitselftoseeifitcouldimproveitscontribution toitscontainingsystem Withinthatorganizationcreate andcontinuallyrearrange teamswhichhavevarietyandwhichcompetewitheachothersothatusefulvarietyisdifferentiallyrewarded Avoidanyoneteambecomingsodominantthatteamandindividualvarietyaresubmerged Dominancetendstobemonotonal 单一 itcanplayonlyonenote andthatistheoppositeofadaptability Introducenewvarietytotheteam ornewteams astheenvironmentchanges Dispensewithvarietyandcapacitythatclearlyhavenofurtherrelevance NetworkwithotherHASswhichoffervarietyandwhichcomplementtheHASofinterest Combineteamsacrossthenetwork Continuallyreviewthatnetworking So howtospecifytechnologicaladaptability Consideracomputergraphicdisplaytobeprovidedaspartofaninformationdecision action IDA system asystemformakingdecisionsinrealtime operatedbyhumanswithdecisionsupportpartlyfromtechnologicaldevices Wecouldprovidethegraphicdisplayineitheroftwoways 1Withallthenecessaryscreenformatscarefullyanalysed designedusingthebesthumanfactorsprinciples togetherwithaspecificationfortesting 2As1butwiththeadditionofascreenformatterwhichenablesthefutureusertoadaptexistingformats orcreateentirelynewones astheneedsofthejob orhis herparticularidiosyncrasies 喜好 dictate Incorporatingthescreenformatterfromthestartcostslittlemore andperhapsevenlesssinceitmaysimplifydevelopment prototyping etc Whatcanbedoneforagraphicsdisplaycanbedoneformosttechnologicaldevices Itsimplytakesachangeofperspective aparadigmshift tousethejargon 行话 Forexample wecandesigndatabasesforadaptabilityandwecancarefullyspecifythatadaptability Inthefuture wemustbecomesmarter Wecannotaffordtogoonreplacingonerigid short livedsystemwithanother Itisexpensive wastefulofresourcesandgivespoor continuallyinterruptedperformance 7 4DesignGuidelinesofNewSystemsEngineering Considerthefollowingsimplifiedexample Anew fossil fuelpowerstationistobeintroducedtoanunderdevelopedregionsupportingapoor largelyagrarian 耕地的 society Designarobustpowersystemtocontributemaximallytotheregionandtominimizeanyundesirablesideeffects Step1 EstablishSOIObjectivesandRequirementsbyReferencetoContainingSystem s Thecontainingsystemswillinclude Theregionaleconomy Theregionalsociety Theregionalecology TheregionalenergysystemTheobjectivesoftheeconomicsystemmightwellincludeanincreaseinagriculturalproductivity throughmechanizationandcheaperfertilizers andanincreaseinindustrializationleadingtowealthgenerationandabeneficialchangeinthebalanceofimportsandexports Theobjectivesoftheregionalsocietywouldbetoflourish andtoenhancetheperceivedqualityoflifebyusingtheincreaseinelectricalpowerandwealth Theregionalecologycouldhardlybesaidtohaveobjectives sinceitisnotapurposefulsystem However wemayascribepurposetoit The objectives oftheregionalecologyaretomaintainthevarietyandbalanceoffloraandfauna somaintainingthebiosphereonwhichtheregionisfounded Powergenerationintentstructure Theobjectivesoftheregionalenergysystemwouldbetogenerateanddistributeaffordablepowerforthewholeregion safely cleanly efficiently continuouslyandsufficienttomeetthedevelopingneed Sincethesearetheexpectationsfromthenewregionalpower generationsystem themeasureofoursystemwouldbeinitssuccessincontributingtoalltheseobjectives notsimplythoseofgeneratingpower AsFigure12 7shows theobjectivescanbenetworked sopresentingastructuredmission orPrimeDirective forthenewregionalpowergenerationsystem asfollows Tocontributetoaflourishingsocietywithanimprovedqualityoflifeforallthecitizensintheregionthroughtheprovisionofsafe clean affordableelectricalpower Step2 Identify Sibling SystemsandtheirInteractionstobePerturbedbytheSOIPerturbedsystemsincludealmostallofthoseintheregion social economic ecological transportation etc Fossil fuelforthepowerstationmustbemined causinganincreaseinpopulationandinfrastructurearoundtheminingarea s whilesomehigh gradefuelsmayneedtobeimported Miningcreatesanecologicalandavisualdisturbance Thefossil fuelwillneedtobetransportedoverinadequateroads soatransportsystemwillneedtobebuilt comprisingnewroads fuelsupplies fueldumps garages lorries mechanics drivers loadingbays unloadingbays conveyers 运送装置 chutes 斜道 etc etc Economicchangewillbeevidentintheinvestmentininfrastructureandtransportationsystems thetrainingandhireofpersonnel theirrelativeaffluenceandconsequentspendingonessentialsandluxurygoods Socialstraincanbeforeseenbetweenthenew haves andtheexisting have nots Theincreaseinpoweravailablewithintheregionwillreducethecostofpower enablingnewbusinessestoformandflourish shiftingthepopulationpatterntowardstownsandcitiesfortworeasons increasedproductivityonthefarmwillreducelabourneeds jobswillbecomeavailableinthetownsasbusinessesform drawtogetherformutualself rewardandcoalesce 联合 接合 Alloftheserepresentdisturbedsiblingsystems Step3 ConceiveComplementarySystemsasNew ModifiedSiblingstoNeutralize 中和 UnwantedPerturbationsComplementarysystemswillberequiredto Absorb reusethewaste effluent dissipation spillfrommining transportation powergeneration distributionandutilization Preventanyreductioninecologicalvariety whichcanalsobereducedbyjudicious 明智 choiceoflocationforapowerstationinrelationtominingareasandcentresofpowerutilization Thismightincludemovingspecies ring fencingsensitiveareas submerginginfrastructure etc Managethemoveoftheregionaleconomysuchthatincreasedagriculturalmechanizationandfertilizerproduction objectives arenotimpededbylackofresources resourcewastageormisapplication andthateconomicconditionsaremadeandkeptsuitableforindustrialization objective toproceedunabated Pump primingofsmallbusinesseswouldbeatypicalfeature togetherwithregionalinvestmentschemes education trainingandspecialisthelp Managetheconsequentsocialimbalanceandtheevolutiontowardsanewsocialorderandequilibrium objectives Investininfrastructure education healthcare job mobility transport housing Easerestrictionsonmovement business security foreigntravel etc Lastly thePrincipleofConnectedVarietysuggeststhatvariety whichtheabovemeasuresaremeanttoenhance shouldbeaccompaniedbyconnectionsbetweenthatvariety Mediapromotionisrequiredtoreportfullyandfreelyonsituationandprogressfromallviewpoints sothatthevarietymayseektheconnectionsneededforstablechangeandexpansion Independentradio TVandnewspapersshouldbeencouraged sothatstrainsintheevolvingsocialfabricbecomeevidentwhilestillsmallandcapableofrelief Step4 DesignSOIasanOpenSystemtoComplementSiblingSystemsinContributingtoContainingSystems ObjectivesTheemergentpropertiesoftheSOIincludethefollowing Poweroutput mean peak qualityneededtosatisfyboththeimmediateandfutureneedsofthearea Availabilityofthatpower includingreliability easeofmaintenance skilllevelstooperateandmaintain reservesoffuel robustnessofthetransportationsystemfeedingfuelin andthedistributionsystemfeedingpowerout apowerstationisanarchetypalopensystem riskofmajorbreakdown Durability survivabilityofthatpower intermsofsusceptibilitytoattackbyenemiesofthebenefitingsociety itsself defencefeaturesifany itsadaptability theexpectedlifetimeofthepowerstation itsreplaceability Theareacoveredbythestation itsfeederroadsanddistributionnetworks Therateoffuelusage itsqualityandavailability Thepowerdissipatedintothebiosphere Manpowerandmaterialstodesign construct train operateandmaintain Etc etc Step5 PartitionSOI PromotingInternalConnectedVariety AvoidingDominance Figure12 8outlinesinbroadtermsaviewofanelectricalpowergenerationsystem withtheemphasisontheopennessandflow i e theconnectivityofthesystemswitheachotherandwiththeirsiblings notshowninthepicture Notethat althoughthepowergenerationsystemisopen itnonetheless 但是 hascontrolsaplenty 丰富地 particularlyaimedattheinflowsandoutflowstoandfromsiblings intermsofrates amountsandqualities Theoutflowshavebeendividedintoresidues unwanted pollutingandrequiringacomplementarysystemtoneutralizetheireffects andpower wanted Thenetworkofcontrolsgenerallyfeedbackfromrighttoleftastheprocessfeedsforwardfromlefttoright Functionaldesigndoesnottendtorevealvariety Byconcentratingonfunctionindecomposition however opennessismaintainedandvarietycanbeintroducedbyreproducingthefunctionusingdifferentstructures methodsortechniques TheGenericReference Form Modelwouldbeusedtoguideinthatrespect Figure12 9showshowvarietymightbeintroducedinrespectofthemaintaskofenergygeneration Notehowtherearenonodes eachpowergenerationpathisindependentintermsofsources resources facilitiesandoutputs Cross oversconnectthevariety togivestability Suchasystemisextremelyrobust butinvolvessignificantcapitaloutlay 费用 Woulditbeworthit Intheshortterm itwouldprobablybethecasethatoneofthethreesystemswouldprovemoreeconomicalinproducinginexpensivepower butthatsituationneednotlast Ifconditionschangeunexpectedly thesingle modesystemmayfail Thebestsolution then wouldbetodesign inallthree ormore systemsfromthestart toconnectthem toprovidethebulkofthepowerfromthatwhichisthemosteconomic buttomaintaintheoperationoftheothersforuseduringoverhauls 检查 supplyshortages etc Asconditionschanged theburdenofpowergenerationcouldmovesmoothlyandeasilybetweenthedifferentmodesofsupply Addingvarietyandconnectingthatvariety powergeneration Step6 EnhanceSOICohesives DiminishDispersivesThesimplestmethodofencouragingcohesionwithinthesystemistopromotemutualself reward butfirst itisnecessarytoidentifycohesiveanddispersiveinfluenceswhichwouldoperatewithintheSOI Cohesiveinfluencesinclude Perceived 感知 goodremuneration 报酬 includingthanks Highmorale 士气 pride esteem 尊敬 withinthecommunity Goodworkingconditions Comprehensiveinfrastructure internalcommunications administration security Participationinmanagementanddecisions Fullmaintenance spares 备件 testfacilities 装置 skills R Dcapability lookingtofutureneeds Changemanagementsystem evolvingtheSOIinsympathywith 一致 theenvironment Dispersiveinfluencesinclude Betterworkingconditionsandpayelsewhereandaccessibletostaff Lackofperceivedchange Alternativepowergenerationsourcesofferingmoreattractionwithintheregion cleaner safer lessexpensive needinglessskill usingmorelocally availableresources etc Poorperformanceinprimaryroleofgeneratingclean safe affordable continuouspower Lackofsupporttomaintain modifyandevolvetechnologywithinpowergenerationsystemovertime Inabilitytodisposeofresiduessatis