毕业设计外文翻译成本管理计划支持系统工程造价控制策划和规划的新范例.docx

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毕业设计外文翻译成本管理计划支持系统工程造价控制策划和规划的新范例

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）,canbeinfluencedbyfactorsexternal