OperationsManagementThedqesignandmanagementofsystemstomakeproducts,provideservicesanddeliverthemtotheendJsef,Class3:VariabilityandOMITriangleLearningObjectivesVariabilityandProcessAnalysis一Whatisvariabiity?Whatimpactdoesvariabilityhaveonprocesses?一Howwedealwithvariabilityfromaqualitativeperspective?*OMtriangleDeterministicSystemStochasticSystemCharacteristics“Novariability*DemandandsupplyareperfectlymatchedCharacteristics“Variability“DemandandsupplydonotmatchApplication“Process/capacity/bottleneckanalysis*Lineflowchart/Ganttchalt“Calculatetheoreticalcapacityrate/flowtimeApplication*Inventory-buildup/LittlesLaw/PKformula,Calculatelongrunaverageflowtime/inventory/throughputrate“OMtriangle“Strategiestodealwithvariabilityinoperations*Queueingsystem*InventorysystemWhatisVariability?Variabilitycomesfrom.VariableVariableinputETypesofVariabilityPredictableVariabilityUnpredictableVariability.refersto“knowable“refersto“unknowable“changesininputand/orchangesininputand/orcapacityratescapacityratesDemandofpuinakinswillgoupSupplyofpumpkinswillgodownduringThantkssivins丿,沥thecropfeiksBothtypesofvariabilityexistsimultaneouslyPumpkinsaleswillgoupduringThanksgiving,butwedonotknowtheexactsalesofpumpkinspredictableVariabilityUnpredictableVariabilityCanbecontro/ledbymakingchangestothesystem“Wecouldincreaseordecreasethedemandforpumpkinsbyincreasingordecreasingtheprice“Restaurantswilladdstaffduringpeakdemand(Iunch,dinneretcJlstheresultofthe/ackofknowledgeorinformation*Usuallycanbeexpressedwithaprobabilitydistribution*E.8,ExpresstheprobabilityfortheamountofpumpkinproductionCanbereducedbygainingmoreknowledgepfcollectioninformation*Bypayingcloseattentiontoweatherpatterns,wecouldincreasetheaccuracyofourpredictionthatthepumpkincropwill佃iShortReviewonProbabilityDiscreteRandomVariableandProbabilityThrowadice;thenumberyougetisadiscreterandomvariable:曰wp.1/6丶wp.1/6ProbabiityX二4一wp.i/6(Probabiity师wp1Iass5Wp.1/66wp.1/6Cumulative1probatbiityP(X=2=1/6PfX2=PX=1orX=2=1/3PfX2.1=P(X=1orX=2=1/3123456左PfX=石i5afunctionofxcalledthecumulativedistributionfunction(CDF)ShortReviewonProbabilityContinuousRandomVariableandProbabilityThetimebetweentwocustomersarrivaltimesisacontinuousrandomvariableProbatbif青P宣F肇锣tyI/TCumulativedistributionfunction(CDP)Discretevs.ContinuousDistributions林eesq些nContinuousrandom/-】)PX三)=I/(x)xvariableX