测绘工程英文论文.docx

测绘工程英文论文.docx

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测绘工程英文论文

ReductionofShort-IntervalGPSDataforConstructionOperationsAnalysis

JohnHildreth,M.ASCE1;MichaelVorster,M.ASCE2;andJulioMartinez,M.ASCE3

Abstract:

Thesystemsthathistoricallyhavebeenusedtocollectdatafortimestudiesofconstructionoperationsaremanualinnatureandlimitedtotheobserver'sfieldofview.GlobalPositioningSystem（GPS）technologyincorporatedintoanonboardinstrumentationsystemcanbeusedtoautonomouslycollectpositionandvelocitydatawithoutthefieldofviewlimitation.Datamustbecollectedatashorttimeintervaltoprovidethelevelofdetailnecessaryforoperationsanalysis.Thustheissuebecomesmanagingthedataandidentifyingtherelativelykeyrecordsthatmarkthestartandstopofactivities.Afieldobserveridentifiesthekeytimesinrealtimewith

instantaneousdecisionsofwhenoneactivitystopsandthenextstartsbasedonenormousvolumesofvisualinformation.ThisworkdevelopedamethodologyformakingequivalentdecisionsbasedonGPSdataandpresentstheproceduresdevelopedtoidentifythekeyrecordsnecessarytocalculateactivitydurations.Acasestudyisusedtoillustrateapplicationofthesystemtoanearthmovingoperation.

Also,itispostulatedhowtheinformationcanbeusedindiscreteeventsimulation.

DOI:

10.1061/（ASCE）0733-9364（2005）131:

8（920）

CEDatabasesubjectheadings:

Geographicinformationsystems;Constructionindustry;Dataanalysis;Informationmanagement;Timestudies.

Introduction

Timestudieshistoricallyhavebeenperformedtorecordthetimerequiredtocompletevariousconstructiontasks（Oglesbyetal.1989）.Theoriginaltimestudysystemwasthestopwatch,whichhassincebeenreplacedbytime-lapsevideorecordings.Thesesystemsaremanualinnatureandlimitedtothefieldofviewoftheobserver,orwhatiswithinthelineofsightoftheobserver.Recently,analystshaveturnedtotechnologyfornewtools.Whetheranobserverperformsthestudyinthefieldwithastopwatchortheoperationisfilmedforpreliminaryreviewanddatareductionintheoffice,theinformationislimitedtothefieldofviewoftheobserverorcamera.Analystshavelookedtoon-boardinstrumentationasadatacollectiontoolusefulbeyondthefieldofview.

GlobalPositioningSystem（GPS）technologyincorporatedintoanonboardinstrumentationsystemcanprovidepositionandvelocitydataasapotentialsolutiontothefield-of-viewissue.However,recordingdatafrequentlyenoughtoprovidegoodre-sultsproducesaverylargevolumeofdata.Withseveralthousanddatarecordsproduceddailyoneachpieceofinstrumentedequip-ment,theissuebecomesmanagingthedataandidentifyingtherelativelyfewkeyrecordsthatmarkthebeginningandendoftheactivitiesbeingstudied.Regardlessofthetoolimplemented,theprocessisperformedinfourphases:

datacapture,preliminaryreview,datareduction,anddataanalysis.ThetoolsusedineachphaseforvarioussystemscanbeseeninTable1.

Afieldobserveridentifiesthekeytimesinrealtimewithin-stantaneousdecisionsofwhenoneactivitystopsandthenextstartsbasedonenormousvolumesofvisualinformation.ThisworkdevelopedamethodologyformakingequivalentdecisionsbasedonGPSdata,specificallytoanswerthequestion,Howcanthelargevolumeofshort-intervalGPSdatacollectedbeauto-maticallyreducedtothesmallvolumeofkeydiscretepointsthatmarkthestartandstopofactivities?

Thispaperbrieflydescribesthehardwareusedtorecordthe

necessaryGPSdataandpresentsproceduresdevelopedtoidentifythekeyrecordsnecessarytocalculateactivitydurations.Acasestudyisusedtoshowtheapplicationofthesystemtoanearth-movingoperation.Thispaperalsopostulateshowtheinformationfromthedatacanbeusedindiscreteeventsimulations.Descrip-tionsofdiscreteeventsimulationappliedtoconstructionopera-tionscanbefoundinMartinezandIoannou（1995）,IoannouandMartinez（1996a）,Martinez（1998）,Sangarayakul（1998）,CorandMartinez（1999）,andIoannou（1999）.

PreviousWork

AnearlyuseofGPStocollectproductivitydatawasapilotstudydesignedtoprovidecurrentinformationregardingearthworkoperations（Ackroyd1998）.PositioninformationwastransmittedviaradioandrecordedbyaremotePCat2-minintervalsandattheclosureofproximityswitchesonleversofarticulatedhaulersandmotorscrapers.Intheinitialphase,analysisofthedatafocusedonmeasuringcycletimes,butnorealanalysiswasperformedofpositionsbetweenevents.Inasecondphase,straingaugeswereusedtoestimatepayloadandtherebyprovideproductivitydata.ThisworkdepictsthepotentialofGPSforrecordingdatafromearthmovingoperationsbutfocusesonthehardwareissuesratherthanthedatareductionissues.Ackroydconcludesthattheinformationmayaddvaluetomonitoringandschedulingtasksbutdoesnotaddressuseofthedataforanalyzingearthmovingoperations.

FieldDataReduction

Oglesbyetal.（1989）pointoutthatthepurposeofatimestudyistorecordthetimesofvariousactivitiesthatmakeupanoperation.Thesimplesttimestudies—stopwatchstudies—relyontheobservertodecidethepointintimeatwhichactivitiesstartandstop.Oglesbyetal.（1989）notethatplacingthisresponsibilityontheobserverlimitstheusefulnessofthedata.Observerscanhavedifferencesinopinion,datarecordedbyasingleobservermayvaryovertime,availableinformationisstrictlylimitedtothatrecordedandissubjecttothephysicallimitationsoftheobserver.Additionally,theinformationrecordedisstrictlylimitedtothefieldofviewoftheobserver.

BjornssonandSagert（1994）presentedPAVIC+asacomputer-basedsystemtoextractdatafromvideorecordingofconstructionoperations,includingactivitydurations.Eachactivityinstanceiscalledasegmentanddefinedbyastartandstoptime.Threetoolsareavailableforregisteringsegments:

start-stoptime,cycletime,andconsecutivetime.Thestart-stoptimetooloperateslikeastopwatch:

theuserindicatesthroughkeystrokesboththestartandstoptime.PAVIC+readsthetimeofthekeystrokefromatimestampplacedontheaudiotrackandrecordsit.Thecycletimetoolisusedwhenthesameworksequenceisrepeated.Thekeystrokeusedtoindicatethestopofanactivityalsoindicatesthestartofthesuccessiveactivity,whicheliminatestheneedtopresstwokeyssimultaneously.Theconsecutivetimetoolisappropriateforagroupofcorrelatedactivities,suchasacraneservingmultiplecrews.Eachactivityisassignedauniquekeythatisstruckwhentheactivityends.Thiskeystrokeindicatesthestopoftheassociatedactivityandthestartofthesuccessiveactivity.

Frank（2001）describesaverysimilarsystemusedtoextractinformationfromdigitalvideo.HepresentsanddiscussestheDigitalVideoAnalysisTool（DVAT）andnotesthatPAVIC+wasthebasisonwhichDVATwasdeveloped.DVATisasoftwarepackagespecificallydevelopedforstrippinginformationfromdigitalvideo.Theextractedinformationcanbeusedtogeneratecrewbalancechartsortodevelopinputforcomputersimulationmodels.

Thesetraditionaldatacollectionmethodshaverelieduponmanualtoolslimitedtothefieldofviewoftheobserver.Researchershaveturnedtotechnologyfortoolsthatarebothautomatedandnotrestrictedtofieldofview.Kannan（1999）describestheuseofonboardinstrumentationsystemsforrecordingdatafromearthmovingoperations.HeusedmechanicalparametersrecordedbytheVitalInformationManagementSystem（VIMS）andtheTotalPayloadManagementSystem（TPMS）producedbyCaterpillartoobtainoperationaldata.Suchsystemsplaceavirtualobserverintheequipment,andthustheequipmentisalwaysinthevirtualfieldofview.

Kannan（1999）statesthatwhenusingonboardinstrumentation,thesensorsmustbeabletodetectachangeinthestatusofthetruck.Thischangeinstatusindicatesthestartorstopofanactivity.KannanandVorster（2000）statethatmechanicalparameterscanbetranslatedtoproductionmeasuresthroughtheuseofsurrogatemeasuresandprotocolrules.Kannan（1998）describestheuseofsuspensionstrutpressure,gearcontrolleverposition,bedraiseswitchposition,andspeedtoderivethedurationoftruckcyclecomponents.Truckcyclecomponentsoractivitiesaredefinedintermsoftheparameters.

Itisevidentfromtheliteraturereviewedthattraditionaldatacollectionmethodsarelimitedbytheabilityofanobservertoinstantaneouslydecideactivitystartandstoptimeswithinanarrowandstaticfieldofview.Moderntechniquesremovethislimitationbyusingsensor-baseddata-collectiontechniquestoidentifykeytimesthroughchangesinsensoroutput.Athoroughunderstandingofthemethodsforreviewing,reducing,andanalyzingGPSdatafromconstructionoperationsrequiresbackgroundknowledgeofhowandwhatdataarecollected.

DataCapture

AnautomateddatacapturesystembasedonGPStechnologywasusedtorecordtherawdataatauser-specifiedtimeinterval,includingdate,time,velocity,andhorizontalposition.Thesystemconsistsofadatabox,junctionbox,andsensorpackandwasdevelopedbasedonfieldevaluationsofcommerciallyavailablesystems.ThedataacquisitionandstorageboxisaweathertightenclosurethathousesthesystemcircuitryandtheCompactFlashmediaonwhichthedataisstored.ThesensorpackconsistsofaGarminGPS-35LVCreceiverandaVector2XmagneticcompassmanufacturedbyPrecisionNavigation,Inc.InadditiontotheGPSandcompass,thesystemhasbeendevelopedsuchthatadditionalanaloganddigitalsensorscanbeincorporatedintothesystemforfutureresearch.Thejunctionboxservesasacentra