《系統(tǒng)工程第二章》課件

Chapter2MethodologicalFrameworksandSystemsEngineeringProcesses

(方法論框架和系統(tǒng)工程過程)12007SYSTEMSENGINEERINGChapter2MethodologicalFrameThereareanumberofframeworks（框架、體系）thatwemightusetocharacterize（描繪）systemsengineeringefforts.Wewilldescribesomeoftheminthischapter.Withoutasoundandwell-understoodproductline,orprocess,fortheacquisitionorproductionoflargesystems,itisverylikelythattherewillbeanumberofflaws（缺點(diǎn)）intheresultingsystemitself.Thus,thedefinition,development,anddeployment（部署）ofanappropriate（恰當(dāng)?shù)模﹑rocess,orsetofprocesses,forsystemsproductionisveryimportant.4/1/202422007SYSTEMSENGINEERINGThereareanumbero2.1INTRODUCTIONInthischapterwefirstdiscussthenatureofsystemsacquisition（收購）,production（生產(chǎn)）,procurement（采購）,ormanufacturing（制造業(yè)）.Wewillgenerally（通常）usethewordacquisitiontodescribeeachoftheseefforts.

Assystemsengineers,weareprimarilyconcernedwiththefunctionalandphysicalarchitecturesthatleadtoimplementationarchitecturesandtheresultingdetaileddesignofsystemsofalltypes.

Designanddevelopmentisveryimportant,eventhoughtheacquisitionorproductionprocessalsodependsuponsuccessinthedefinitionanddeployment（部署）phasesofthelifecycle.Designanddevelopmentisacreativeprocessthroughwhichsystemproducts,presumedtoberesponsivetoclientneedsandrequirements,areconceptualizedorspecified,manufacturedorotherwiseproduced,andfieldedorimplementedinsuchawaythattheycanbemaintainedovertime.

4/1/202432007SYSTEMSENGINEERING2.1INTRODUCTION2.1INTRODUCTIONTherearefourprimaryingredientsinourdefinitionofdesignanddevelopment,andtheyapplytosoftwaredesignaswellastothedesignofhardwareandphysicalsystems.Developmentresultsfromspecifications（規(guī)格）orarchitectureforaproductorsystem.Developmentisacreativeprocess.Developmentactivityincludesdesigneffort,whichisconceptualinnature.Asuccessfuldesignanddevelopmentmustbebroadlyresponsivetoclientneedsandrequirements.4/1/202442007SYSTEMSENGINEERING2.1INTRODUCTIONT2.1INTRODUCTION

Goodsystemsengineeringpractice

（實(shí)踐）requiresthatthesystemsengineerberesponsivetoeachofthesefouringredientsforqualitydesignanddevelopmentefforts.

Thefinalingredientrequiresasetofneedsandrequirementsoftheclientforthedesiredproduct,process,orsystem.Thisinformationrequirementservesastheinputtothesystemsengineeringprocessthatleadstodesign.Systemsengineeringiscreative,anditisaprocessthatisconceptualandpragmatic（概念和務(wù)實(shí)）

innature.Theinitialresultofthiscreative,conceptual,andpragmaticprocessisinformationconcerningthespecificationsorarchitecturefortheproductorservicethatwillultimatelybemanufactured,implemented,installed,orbroughttofruition（享用）insomeotherway.Alaterresultisthesystemitselfandplansforitsevolutionovertime.4/1/202452007SYSTEMSENGINEERING2.1INTRODUCTIONG2.1INTRODUCTIONInthedetailedeffortsthatfollow,wefirstdiscusssystemsengineeringmethodologyandsystemsengineeringlifecyclesasnecessaryelementsinthesystemsengineeringprocess.Thisleadstoanumberofconceptualframeworksforsystemsengineeringprocesses.4/1/202462007SYSTEMSENGINEERING2.1INTRODUCTIONIn2.1INTRODUCTIONInthischapter,wewilldiscussthesystemsacquisition,orproduction,processintermsofanumberofstepsandphasesthatmaycomprisethisprocess.4/1/202472007SYSTEMSENGINEERING2.1INTRODUCTIONIn2.2METHODOLOGICALFRAMEWORKSFOR

SYSTEMSACQUISITIONORPRODUCTION

Inthissectionwepresentandexplainthecompletesystemsengineeringprocesswithemphasisonframeworksforsystemsmethodologyanddesign.Theframeworkconsistsofthreedimensions（方面）

:Alogicdimension

（邏輯層面）

thatconsistsofthreefundamentalstepsAtimedimensionthatconsistsofthreebasiclifecyclephasesAperspectivesdimension（觀點(diǎn)層面）thatconsistsofthreestagesorlifecycles4/1/202482007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Weenvision（設(shè)想）athree-performancelevelhierarchy（三層次結(jié)構(gòu)性能）forsystemsengineeringphasedefforts,suchasshowninFigure2.2.Thisthree-levelstructuredhierarchycomprisesasystemsengineeringlifecycleandisoneoftheingredientsofsystemsengineeringmethodology.Itinvolves:SystemdefinitionSystemdevelopmentSystemdeployment4/1/202492007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Weillustrateforwardflowofinformation,andfeedback（反饋）fromonephasetotheother.Usually,thisisneededasasituationinwhichinformationonlyflowsinonedirectionfromonephasetoasubsequentphasewillnotallowforiterativeimprovement.

（迭代改進(jìn)）

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Itisgenerallyalsoverydesirabletoallowforlearningasthelife-cycleprocessisiterativelyrepeated（反復(fù)迭代）.Figure2.3illustratesthreedifferentinformationflowpatterns.Generally,theonewithlearningandfeedbackistobepreferred.Wewill,however,discusssomeextensionsofthebasic"waterfall"life-cyclemodel,illustratedontheleftsideofFigure2.3.

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Asweshallsoondiscuss,thisthree-phaselifecyclemaybeexpandedintoalifecyclecomprised（包含）ofalargernumberofphases.Generallythenumberofphasesisinthevicinity（周圍地區(qū)）ofseven,althoughitmaycontainquiteafewmorethansevenphases4/1/2024122007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Regardlessof（不管、盡管）thewayinwhichthesystemsengineeringlife-cycleprocessischaracterized,andregardlessofthetypeofproductorsystemorservicethatisbeingdesigned,allcharacterizationsofthephasesofthesystemsengineeringlifecycleswillnecessarilyinvolve:FormulationoftheProblem

（問題的規(guī)劃）—inwhichtheneedsandobjectivesofaclientgroupareidentified,andpotentiallyacceptabledesignalternatives,oroptions,areidentifiedorgenerated.AnalysisoftheAlternatives

（變量的分析）—inwhichtheimpactsoftheidentifieddesignoptionsareidentifiedandevaluated.Interpretation（解釋、說明）

andSelection

—inwhichtheoptions,oralternativecoursesofaction,arecomparedbymeansofanevaluationoftheimpactsofthealternativesandhowthesearevaluedbytheclientgroup.Theneedsandobjectivesoftheclientgrouparenecessarilyusedasabasisforevaluation.Themostacceptablealternativeisselectedforimplementationorfurtherstudyinasubsequentphaseofsystemsengineering.4/1/2024132007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Ourmodelofthestepsofthelogicstructureofthesystemsprocess,showninFigure2.4,isbaseduponthisconceptualization.Asweshallalsoindicateinmuchmoredetaillater,thesethreestepscanbedisaggregated（分解）intoanumberofothers.

Eachofthesestepsofsystemsengineeringisaccomplishedforeachofthelifecyclephases.4/1/2024142007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Aswehavenoted,therearegenerallythreedifferentsystemsengineeringlifecycles.Theserelatetothethreedifferentstages

ofeffortthatareneededtoresultinacompetitiveproductorserviceinthemarketplace:Research,development,test,andevaluation(RDT&E)SystemacquisitionorproductionSystemsplanningandmarketing

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Thuswemayimagineathree-dimensionalmodelofsystemsengineeringthatiscomprisedofstepsassociatedwitheachphaseofalifecycle,thephasesinthelifecycle,andthelifecyclesthatcomprisethecoarsestructure（大體框架）orstagesofsystemsengineering.4/1/2024162007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Figure2.5illustratesthisacrossthreedistinctbutinterrelatedlifecycles,forthethreestepsandthreephasesthatwehavedescribedhere.4/1/2024172007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Thesystemsplanningandmarketinglifecycleisintendedtoyieldanswerstothequestion;Whatisindemand?

Theresearch,development,test,andevaluationlifecycleisintendedtoyieldanswerstothequestion;Whatis(technologically)possible(withinreasonableeconomicandotherconsiderations)?Theacquisitionlifecycleisintendedtoyieldanswerstothequestion;Whatcanbedeveloped?Itisonlyintheregionwherethereisoverlap（重疊）,actuallyinann-dimensionalspace,thatresponsibleactionsshouldbeimplementedtobringaboutprogramsforallthreelifecycles.Thissuggeststhattheneedsofonelifecycleshouldnotbeconsideredindependentlyoftheothertwo.4/1/2024182007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Figure2.6attemptstorepresentthisconceptuallyfortwo-dimensionalrepresentationsofthepossibilityspaceforeachlifecycle.

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Eachofthelogicalstepsofsystemsengineeringisaccomplishedforeachofthelife-cyclephases.Therearegenerallythreedifferentsystemsengineeringlifecyclesorstagesforacompletesystemsengineeringeffort,aswehaveindicated.Thuswemayimagineathree-dimensionalmodelofsystemsengineeringthatiscomprisedofstepsassociatedwitheachphaseofalifecycle,thephasesinthelifecycle,andthelifecyclesorstagesofacompletesystemsengineeringeffort.4/1/2024202007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Figure2.7illustratesthisframeworkofsteps（步驟）,phases（方面）,andstages（階段）asathree-dimensionalcube.Thisisonethree-dimensionalframework,intheformofamorphological（形態(tài)學(xué)）box,forsystemsengineering.4/1/2024212007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Amethodology（方法學(xué)）isanopensetofproceduresforproblemsolving.Consequently（因此、所以）,amethodologyinvolvesasetofmethods,asetofactivities,andasetofrelationsbetweenthemethodsandtheactivities.Touseamethodologywemusthaveanappropriatesetofmethods.Generally,theseincludeavarietyofqualitative（定性的）andquantitativeapproachesfromanumberofdisciplinesthatenableformulation（構(gòu)思、規(guī)劃）,analysis,andinterpretationofthephasedeffortsthatareassociatedwiththedefinition,development,anddeploymentofbothanappropriateprocessandtheproductthatresultsfromuseofthisprocess.

Associatedwithamethodologyisastructuredframeworkintowhichparticularmethodsareassociatedforresolutionofaspecificissue.4/1/2024222007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS2.2METHODOLOGICALFRAMEWORKSFOR

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Letusnowdevelopthestructuredframeworkofsteps,phases,andstagesinsystemsengineeringinmoredetail.4/1/2024232007SYSTEMSENGINEERING2.2METHODOLOGICALFRAMEWORKS(1)LogicalStepsofSystemsEngineering

Aswehavenoted,allcharacterizationsofsystemsengineeringwillnecessarilyinvolvethreelogicalsteps[1-4]:FormulationofthesystemsengineeringproblemunderconsiderationAnalysistodeterminetheimpactsofthealternativesInterpretationoftheseimpactsinaccordancewiththevaluesystemofthedecisionmaker(s),andselectionofanappropriateplanofactiontocontinuetheeffort.Thesethreesteps,oranexpansiontheretotomoreexplicitlyindicatetheactualactivitiesassociatedwitheachphase,areconductedateachandeveryphaseofthesystemsengineeringlifecycle.4/1/2024242007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(1)LogicalStepsofSystemsEngineering

Wecanexpand（擴(kuò)展）thethreefundamentalstepsofsystemsengineeringinmanyways.However,probablythemostusefulexpansionisthesevenstepsidentifiedbyHall[5].Ourconstrual(解釋)ofthesesevenstepsofsystemsengineeringandtheirrelationtothethreebasicstepsofformulation,analysis,andinterpretationfollows.4/1/2024252007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(1)LogicalStepsofSystemsEngineering

FormulationProblemDefinition.（問題的定義）

Thisstepinvolvesisolating（分離）,quantifying（量化）,andclarifying（闡述）theneedthatcreatestheproblemanddescribingthesetofenvironmentalfactorsthatconstrainsalterables（約束變量）forthesystemtobedeveloped.Itinvolvesidentifyingasetofneeds,alterables,andconstraintsassociatedwiththeissueformulation.ValueSystemDesign.（價(jià)值系統(tǒng)設(shè)計(jì)）

Thisstepinvolvesselectionofthesetofobjectivesorgoalsthatguidesthesearchforalternatives.Valuesystemdesignenablesdeterminationofthemultidimensionalattributesordecisioncriteriaforselectingthemostappropriatesystem.Itinvolvestheidentificationandvalidation（確認(rèn)）ofasetofobjectivesandobjectivesmeasures.SystemSynthesis.（系統(tǒng)綜合）

Thisstepinvolvessearchingfor,orhypothesizing（假定、猜測）,asetofalternativecoursesofactionoroptions.Eachalternativemustbedescribedinsufficientdetailtopermitanalysisoftheimpactsofimplementationandsubsequentevaluationandinterpretationwithrespecttotheobjectives.Aspartofthisstep,weidentifyanumberofpotentialalternativesandassociatedalternativesmeasures.4/1/2024262007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(1)LogicalStepsofSystemsEngineering

AnalysisSystemAnalysisandModeling（系統(tǒng)分析與建模）.Asapartofthisstep,wedeterminespecificimpacts（確定具體的影響因素）orconsequencesofthealternatives（變量結(jié)果）thatwerespecifiedasrelevanttotheissueunderconsiderationbythevaluesystem.Theseimpactsmayrelatetosuchimportantconcernsasproductquality,market,reliability,cost,andeffectivenessorbenefits.Thereareavarietyofsimulationandmodelingmethods,andagreatvarietyofoperationsresearchapproachesthatareofpotentialvaluehere.RefinementoftheAlternatives（細(xì)化變量）.Aspartofthisstep,weattempttoadjust,andhopefullyoptimize,thesystemvariablesinordertobestmeetsystemobjectivesandsatisfysystemconstraints.4/1/2024272007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(1)LogicalStepsofSystemsEngineering

Interpretation

DecisionMaking（制定策略）.

Thisstepinvolvesevaluatingtheimpactsorconsequencesofthealternativesand,thereby,interpretingthealternativesintermsoftheextenttowhichtheyachieveobjectives.Thealternativesareidentifiedinsystemsynthesisandsubsequentlymodeledandrefinedintheanalysisstepsofeffort,inaccordancewithsatisfactionofobjectivesassociatedwiththevaluesystem.Thisenablesinterpretationoftheseevaluationssuchthatallalternativescanbecomparedrelativetohumanvalues.Oneormorealternatives,orcoursesofaction,canthenbeselectedforadvancingtothenextstep.PlanningforAction.

Thisstepinvolvescommunicatingtheresultsoftheefforttothispointandlookingaheadtothenextphaseofthesystemsengineeringlifecycleunderconsideration.Thisincludessuchpragmaticeffortsasschedulingsubsequentefforts,allocatingresourcestoaccomplishthem,andsettingupsystemmanagementcontrols.Ifweareconductingasinglephaseeffort,thisstepwouldbethefinalone.Moregenerally,itleadstoanewphaseofeffortincontinuationofasystemsengineeringlifecycle.4/1/2024282007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(1)LogicalStepsofSystemsEngineering

figure2.8indicatesthewaterfallnatureofthesesevenstepsofsystemsengineeringandtheirrelationtothethreefundamentallogicalsteps.Thesevenstepsofsystemsengineeringaregenerallycarriedoutinaniterativefashionforeachphaseofthesystemsengineeringlifecycle.4/1/2024292007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(1)LogicalStepsofSystemsEngineering

Becausetheeffortsandpurposesofthevariousphasesofthelifecyclearequitedifferent,thespecifictoolsandmethodsthatareappropriatetoaccomplisheachofthesevenstepscanbeexpectedtobequitedifferentfromonesystemsengineeringprocessphasetoanother.Itisquitepossibletogobacktorefineandimprovetheresultsofanyearlierstepasaconsequenceoftheresultsofanylaterstep.WedonotshowtheseiterativefeedbackloopsinFigure2.8.4/1/2024302007SYSTEMSENGINEERING(1)LogicalStepsofSystemsE(2)Life-CyclePhasesofSystemsEngineering

Aswehaveoftenindicatedatypicalsystemsengineeringlifecyclehasthreebasicphases—definition,development,anddeployment.Forlargesystems,thesethreephasesneedexpansionintoanumberofmorefinelydefinedphases.Thisenablesthevariousphasestobebetterunderstood,communicated,andcontrolledinordertosupporttrustworthysystemsengineeringefforts.Beforedescribingspecificlife-cyclemethodologieslaterinthischapter,wepresentandexplainageneralandveryusefulseven-phaselife-cycleexpansionanditsrelationtothebasicthree-phasesystemsengineeringlifecyclethatwepresentedinFigures2.2and2.3.Figure2.9illustratestheseven-phaselifecycle,actuallyrepresentingacquisitionorproduction,thatwenowconsider.4/1/2024312007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

Thesevenphasesinthislifecyclemaybedescribedasfollows:4/1/2024322007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

SystemDefinition

1.RequirementandSpecifications.Thefirstpartofsystemengineeringeffortresultsintheidentificationofuserrequirementsandthetranslationoftheseintotechnologicalspecificationforaproduct,process,orsystem.

Thegoalofthisphaseistheidentificationofclientandstakeholderneeds,activities,andobjectivesforthefunctionallyoperationalsystem.Thismeansthatinformationisanecessaryingredientandresultsinthemandatetoobtain,fromtheclientforasystemsengineeringeffort,asetofneedsandrequirementsfortheproduct,process,orsystemthatistoresultfromtheeffort.Thisinformationrequirementservesastheinputtotherestofthesystemsengineeringprocess.

Thisphaseresultsintheidentificationanddescriptionofpreliminaryconceptualdesignconsiderationsforthenextphase.Itisnecessarytotranslateoperationaldeploymentneedsintorequirementsspecificationssothattheseneedsmaybeaddressedbythesystemdesignanddevelopmentefforts.

Thus,informationrequirementsspecificationsareaffectedby,aswellasaffect,eachoftheotherdesignanddevelopmentphasesofthesystemsengineeringlifecycle.4/1/2024332007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

2. PreliminaryConceptualDesignandSystemArchitecting.Theprimarygoalofthisphaseistodevelopseveralconceptsthatmightworkthatareresponsivetothespecificationsidentifiedinthepreviousphaseofthelifecycle.

Apreliminaryconceptualdesign,onethatisresponsivetouserrequirementsforthesystemandassociatedtechnicalspecifications,shouldbeobtained.

Rapidprototypingoftheconceptualdesignisclearlydesirableformanyapplicationsasonewayofachievinganappropriateconceptualdesign.Severalpotentialoptionsareidentifiedandthensubjectedtoatleastapreliminaryevaluationinordertoeliminateclearlyunacceptablealternatives.Thesurvivingalternativesarenextsubjectedtomoredetaileddesignefforts,andmorecompletearchitecturesorspecificationsareobtained.Itisatthisphasethattheenterprisearchitecture,andperhapsapreliminaryfunctionalarchitecture,forthesystemareinitiallyidentified.Functionalanalysisapproachesareparticularlyusefulinthisphaseofeffort.4/1/2024342007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

LogicalDesignandProductArchitecturalSpecifications.

Thisphaseresultsinanefforttospecifythecontentandtoprovidemoredetailtotheassociatedhighlevelarchitecturesforthesystemproductinquestion.Specificationsaretranslatedintodetailedrepresentationsinlogicalformsuchthatsystemdevelopmentmayproceed.Thislogicaldesignproductissometimescalledaphysicalarchitecture,andtheproductarchitecturalspecificationsarerealizedintermsofthisphysicalarchitecture,sometimescalledengineeringarchitecture,ofthesystemthatwillultimatelybeimplemented.4/1/2024352007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

DetailedDesign,Production,andTesting.

Thegoalofthisphaseisasetofdetaileddesignspecificationsthatshouldresultinausefulsystemproduct.

Thereshouldexistahighdegreeofuserconfidencethatausefulproductwillresultfromdetaileddesign,ortheentiredesigneffortshouldberedoneorabandoned.

Anotherproductofthisphaseisarefinedsetofspecificationsfortheoperationaldeploymentandevaluationphasesofthelifecycle.Again,designalternativesareevaluated,andafinalchoiceismade,whichcanbedevelopedwithdetaileddesigntesting,andatleastpreliminaryoperationalimplementation.

Thisresultsintheimplementationarchitectureforthesystem.Utilizationofthisimplementation(ordetaileddesign)architectureresultsintheactualsystem.Preparationsforactualproductionandmanufacturingaremadeinthisphase.Thesystemisproducedhere,ofteninanoutsourcedmanner,byanimplementationcontractor.4/1/2024362007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

System

OperationandMaintenanceOperationalImplementation.Aproduct,process,orsystemisimplementedorfieldedforoperationalevaluation.Preliminaryevaluationcriteriaareobtainedandmodifiedduringthefollowingtwophases.4/1/2024372007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

OperationalTestandEvaluation(andAssociatedModification).

Onceimplementationhasoccurred,operationalevaluationandtestofthesystemcanoccur.Thesystemdesignmaybemodifiedasaresultofthisevaluation,leading(hopefully)toanimprovedsystemand,ultimately,operationaldeployment.Generally,thecriticalissuesforevaluationareadaptationsoftheelementspresentintherequirementsspecificationsphaseofthesystemsengineeringlife-cycleprocess.

Asetofspecificevaluationtestrequirementsandtestsareevolvedfromtheobjectivesandneedsdeterminedintherequirementsspecifications.Theseshouldbesuchthateachobjectiveandcriticalevaluationcomponentcanbemeasuredbyatleastoneevaluationtestinstrument.Ifitisdetermined,perhapsthroughanoperationaltestandevaluation,thattheresultingsystemsproductcannotmeetuserneeds,thelife-cycleprocessrevertsiterativelytoanearlierphase,andtheeffortcontinues.

Animportantbyproductofsystemevaluationisdeterminationofultimateperformancelimitationsforanoperationallyrealizablesystem.Often,operationalevaluationistheonlyrealisticwaytoestablishmeaningfulinformationconcerningfunctionaleffectivenessoftheresultofasystemsengineeringeffort.Successfulevaluationisdependentuponhavingpredeterminedexplicitevaluationstandards.4/1/2024382007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

OperationalFunctioningandMaintenance.Thelastphaseincludesfinalacceptanceandoperationaldeployment.Maintenanceandretrofitcanbedefinedeitheraspartofthisphaseorasadditionalphasesinthelifecycle.Eitherisanacceptablewaytodefinethesystemlifecycleforsystemacquisitionorproduction.4/1/2024392007SYSTEMSENGINEERING(2)Life-CyclePhasesofSyste(2)Life-CyclePhasesofSystemsEngineering

Wemaysummarizethesephasedactivitiesasfollows.Therequirementsandspecificationphaseofthissystemsengineeringlifecyclehasasitsgoaltheidentificationofclientorstakeholderneeds,activities,andobjectivesforthefunctionallyoperationalsystem.Thisresultsinidentificationanddescriptionofpreliminaryconceptualdesignconsiderationsforthenextphase.Itisnecessarytotranslateoperationaldeploymentneedsintorequirementsspecificationssothattheseneedsmaybea