毕业设计外文翻译成本管理计划支持系统.docx
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毕业设计外文翻译成本管理计划支持系统
COMPASS-NEWPARADIGMFORPROJECTCOSTCONTROLSTRATEGYANDPLANNING
ByMakarandHastak/AssociateMember,ASCE,DanielW.Halpin,2Member,ASCE,andJorgeVanegas/AssociateMember,ASCE
ABSTRACT:
Theneedtoremaincompetitivewhilegeneratingprofitrequiresmanagementtodevelopinnovative.costmanagementstrategiesthatwillallowthemtodistinguishandcontrolearly-onfactorsthatmightadversely.impactthecostofaproject.
Thispaperdescribesadecisionsupportsystem,COMPASS(CostManagementPlanningSupportSystem)forprojectcostcontrolstrategyandplanning.Throughoutthelifecycleofaproject,COMPASSmethodologyassistsmanagementinevaluatingthepotentialdegreeofcostescalation.Italsoidentifiesattributessuchasmanagementerrors,regulatoryapproval,anderror/rework,thatmightbethecauseforprojectcostescalation.Furthermore,COMPASSassistsmanagementinformulatingacostcontrolstrategywhileutilizingtheirexperienceandpastprojectperformancedata.Theattributesidentifiedbythecostcontrolstrategy,ifcontrolled,wouldminimizetheexpectedloss.
INTRODUCTION
Projectostscalationandcostmanagementareclearlytwoofthemostimportantmanagementconcernsintheintenselycompetitiveenvironmentoftheconstructionindustry.Consequently,itsveryimportantformanagementtodetectatanearlystageofaprojecttheactualorpotentialcostoverruns.Toremaincompetitivewhilegeneratingprofit,managementneedstoidentifyandadoptinnovativecostmanagementstrategies.Thesestrategiesshouldallowthemtoidentifyandcontrolearlyonfactorsthatmightadverselyimpactthecostofaproject.
Todate,variousmethodologieshavebeendevelopedforprojectcostcontrolsuchasearnedvaluesystemmanagement.exceptionreporting,andcosttrendanalysis.However,noneofthesemethodsconsidersatamacroleveltheinfluenceofmanyimportantfactors(orattributes)suchaswaste,projectmanagementpractices,changeorders,anderror/reworkontheprojectcost.Existingmethodsofcostcontrolfocusonidentifyingandcontrollinglineitems(costcomponents)thathavealreadyexperiencedacostescalation.Inotherwords,existingmethodsofcostcontrolrelatetosymptomsratherthanthecause.
Whatisrequired,however,isaparadigmshift.Anewmethodisneededthat,inadditiontorecognizinghesymptoms,identifiesandfocusesourattentionontheattributesthatareapotentialcauseforescalationinthelineitemsforagivenproject.Thenewparadigmshouldhavethecapabilitytoanalyzeagivenprojectwhileincorporatingthepastprojectperformancedataandtheexperienceoftheprojectteam.Thisanalysisshouldidentifyandsuggestcontrolofattributessuchasmanagementerrors,regulatoryapproval,anderror/rework,whichhaveapotentialtoinstigatecostescalationinthelineitemestimate.Moreover,itisofimportancetoidentifyandcontroltheseattributesbeforetheyinfluencetheprojectcost.
Identificationofattributesthatmightberesponsibleforprojectcostescalationisnotsufficientinitself.Whatisequallyimportantistocontroltheinfluenceoftheidentifiedattributesontheprojectcost.Thiswouldrequiredevelopingaproject
costcontrolstrategytoeithereliminateorreducetheimpactofidentifiedattributesonthelineitems,therebyminimizingtheexpectedloss.Existingmethodsofcostcontroldonotassistmanagementindevelopingacostcontrolstrategytominimizetheimpactofallsuchattributesontheprojectcost.Theoptimumstrategywouldidentifyandsuggestcontrolofasetofattributestominimizetheprobableprojectcostescalation.
Toanalyzeandcontroltheimpactoftheseattributesontheprojectcost,itisimportanttocollatethepastprojectperformancedataavailablewiththeuserfirm.Furthermore,thesedatashouldbeanalyzedwithrespecttothenewprojectcharacteristicsbyusinganappropriateanalyticalmedium.Acomputerizeddecisionsupportsystem(DSS)wouldthereforebeadvantageoustoassisttheuserindevelopingasuitableprojectcostcontrolstrategy.
ATTRIBUTEVERSUSLINEITEMS
Thetenn"attribute"(asusedinthepresentpaper)doesnotrefertotheconventionaltenn"lineitems."However,itpertainstothefactorsthatmightberesponsibleforgeneratingcostescalationinthelineitemsofaproject.Thedifferenceisemphasizedtodelineatethepointofdepartureforthisresearch.Inrecentyears,manyresearchershaveaddressedtheissueofcostcontrolbyusingtechniquessuchasMonteCarlosimulation,managementexceptionreporting,andprobabilisticestimating.Nonetheless,theirresearchfothevarianceinlineitems.However,fromthecostmanagementperspective,itwouldbemorebeneficialtoidentifythecauseofvarianceinthelineitems,which,whencontrolled,wouldminimizetheoverallprojectcostescalation.
Duringtheestimatingprocessforagivenproject,wemightassumeacertainstateforattributessuchasmanagementerrors,regulatoryapproval,error/rework,workermorale,andcrewbalance.Theunderlyingconceptofthisresearchisthatduringthecourseoftheprojecttheassumedstateoftheseattributesmightchangeduetoonereasonoranother.Thechangeinstateorlossofequilibriumofanattributemightnotonlyinfluencecertainotherattributesbutalsomightinfluencethelineitemsthatwereestimatedbasedontheassumedstateoftheattribute.This,inturn,mightcauseapercentageescalationintheestimatedprojectcost.
Anattributeisconsideredtobeintheactivestateif,overthecourseoftheproject,thecostorstatusofanattributediffersfromwhatwasassignedtoitattheestimatingstage.Forexample,thelaborproductivityobtainedduringthecourseoftheprojectmightdifferfromwhatwasassumedattheestimatingstage.Similarly,attheestimatingstage,anonactivestatusmightbeassignedtotheattribute,management,orprojectteam.However,thereisapossibilitythatduringthecourseoftheprojectthemanagementorprojectteammightmakeadecisionerror,influencingmanyotherattributes.Thiswouldchangethenonactivestatusoftheattribute,management,orprojectteam,toanactivestate.Theprobabilityandtheresultingcostimpactoftheseeventscannotbeneglected.
Attributestateisdefinedbyusingabinarymode,wherestate=1impliesthattheattributewasinactivestateinthatproject,whereasstate=0impliesotherwise.Thecomplexinterrelationshipbetweentheattributessuggeststhatevenaminorchangeintheassumedequilibriumstateofanattributehasthepotentialtotriggeradominoeffect.Thiseffectcouldnotonlyinfluencesomeotherattributesbutcouldalsoinfluencetheprojectcost.Therefore,thebinarymodeofrepresentationwasconsideredtobemostappropriateforthisresearch,sinceanyintennediatestatebetweenactiveandnonactivewouldnotprovideanyadditionalinfonnation.
THEATTRIBUTES
Forthepurposeofthisresearch,attributesthathaveapotentialtocauseprojectcostescalationwereidentified.Inthepast,severalauthorshaveexaminedtheimpactofisolatedattributesonprojectcostHowever,noprojectmanagementtoolisavailabletoaccountforthecollectiveimpactofallpossibleattributes.Theattributesweredividedintotwogroups,quantifiableandnonquantifiableattributes.Attributesthathaveacostvalueassociatedwiththemintheprojectestimateweredefinedasquantifiableattributes,e.g.,totalmaterialcost,totallaborcost,totalequipmentcost,projectmanagementcost,andtotalcostoftheprojectatendofwork.Attributesthatdonothaveacostvalueassociatedwiththemintheprojectestimateweredefinedasnonquantifiableattributes.Theneedtodifferentiatebetweenquantifiableandnonquantifiableattributesiselaboratedlaterundermodelingassumptions.
FIG.1.ExampleInfluencePattern
Referstothepercentagecostescalationovertheestimatedprojectcost.Tosatisfytheserequirements,aDSSsuchasCOMPASSwouldbemostsuitable.
MODELINGASSUMPTIONS
Theinterrelationshipsbetweenattributes,theresultinginfluencepattern,andtheimpactofattributesontheprojectcosthavebeenstructuredbydefiningthefivefollowingmodelingassumptions:
Assumption1
Ifanattribute,e.g.,F(refertoFig.1)isinfluencedbyasetofattributes,i.e.,CandD,thentheindividualinfluenceoftheattributesinthatsetonF(i.e.,theinfluenceofConFandtheinfluenceofDonF)isconsideredtobeindependent,i.e.
p[(FnC)I(FnD)]=p(FnC)(Ia)
:
.p[(FnC)n(FnD)]-;-p(FnD)=p(FnC)(Ib)
:
:
:
:
)p[(FnC)n(FnD)]=p(FnC)Xp(FnD)(Ie)
Assumption2
Allnonquantifiableattributesareconditionallydependentontheirprecedingattributes,i.e.,anonquantifiableattributecanattaintheactivestateonlyifatleastoneofitsprecedingattributesisintheactivestate;e.g.,attributeF(refertoFig.1)canattaintheactivestate(i.e.,F=1)onlyifatleastoneofitsprecedingattributesCorDisintheactivestate(i.e.,C=1orD=1).
However,thisconstraintisnotapplicableforquantifiableattributes,i.e.,X,Y,andZ(refertoFig.I),becausequantifiableattributes,apartfrombeinginfluencedbytheirprecedingattributes,arealsodirectlyrelatedwithcertainlineitems(e.g.,quantifiableattributetotalmaterialcostwouldberelatedwithmaterialcostassociatedwithvariousotherlineitems),someofwhichmightbeinfluencedbyotheractiveattributesthatwoulddefinethestateofthatquantifiableattribute(e.g.,totalmaterialcost)asactive
Assumption3
Onlythestartingattributes,i.e.,AandB(refertoFig.1),canbeinfluencedbyfactorsexternaltothesystem,