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-IntervalGPSDatafor

ConstructionOperationsAnalysis

JohnHildreth,M.ASCE1;MichaelVorster,M.ASCE2;andJulio

Martinez,M.ASCE3

Abstract:

Thesystemsthathistoricallyhavebeenusedtocollectdatafortimestudiesof

constructionoperationsaremanualinnatureandlimitedtotheobserver'sfieldofview.Global

PositioningSystem（GPS）technologyincorporatedintoanonboardinstrumentationsystemcanbe

usedtoautonomouslycollectpositionandvelocitydatawithoutthefieldofviewlimitation.Data

mustbecollectedatashorttimeintervaltoprovidethelevelofdetailnecessaryforoperations

analysis.Thustheissuebecomesmanagingthedataandidentifyingtherelativelykeyrecordsthat

markthestartandstopofactivities.Afieldobserveridentifiesthekeytimesinrealtimewith

instantaneousdecisionsofwhenoneactivitystopsandthenextstartsbasedonenormousvolumes

ofvisualinformation.Thisworkdevelopedamethodologyformakingequivalentdecisionsbased

onGPSdataandpresentstheproceduresdevelopedtoidentifythekeyrecordsnecessaryto

calculateactivitydurations.Acasestudyisusedtoillustrateapplicationofthesystemtoan

earthmovingoperation.

Also,itispostulatedhowtheinformationcanbeusedindiscreteeventsimulation.

DOI:

10.1061/（ASCE）0733-9364（2005）131:

8（920）

CEDatabasesubjectheadings:

Geographicinformationsystems;Constructionindustry;Data

analysis;Informationmanagement;Timestudies.

Introduction

Timestudieshistoricallyhavebeenperformedtorecordthetimerequiredtocompletevarious

constructiontasks（Oglesbyetal.1989）.Theoriginaltimestudysystemwasthestopwatch,which

hassincebeenreplacedbytime-lapsevideorecordings.Thesesystemsaremanualinnatureand

limitedtothefieldofviewoftheobserver,orwhatiswithinthelineofsightofthe

observer.Recently,analystshaveturnedtotechnologyfornewtools.Whetheranobserverperforms

thestudyinthefieldwithastopwatchortheoperationisfilmedforpreliminaryreviewanddata

reductionintheoffice,theinformationislimitedtothefieldofviewoftheobserverorcamera.

Analystshavelookedtoon-boardinstrumentationasadatacollectiontoolusefulbeyondthefield

ofview.

GlobalPositioningSystem（GPS）technologyincorporatedintoanonboardinstrumentationsystem

canprovidepositionandvelocitydataasapotentialsolutiontothefield-of-viewissue.However,

recordingdatafrequentlyenoughtoprovidegoodre-sultsproducesaverylargevolumeofdata.

Withseveralthousanddatarecordsproduceddailyoneachpieceofinstrumentedequip-ment,the

issuebecomesmanagingthedataandidentifyingtherelativelyfewkeyrecordsthatmarkthe

beginningandendoftheactivitiesbeingstudied.Regardlessofthetoolimplemented,theprocess

isperformedinfourphases:

datacapture,preliminaryreview,datareduction,anddataanalysis.

ThetoolsusedineachphaseforvarioussystemscanbeseeninTable1.

Afieldobserveridentifiesthekeytimesinrealtimewithin-stantaneousdecisionsofwhenone

activitystopsandthenextstartsbasedonenormousvolumesofvisualinformation.Thiswork

developedamethodologyformakingequivalentdecisionsbasedonGPSdata,specificallyto

answerthequestion,Howcanthelargevolumeofshort-intervalGPSdatacollectedbe

auto-maticallyreducedtothesmallvolumeofkeydiscretepointsthatmarkthestartandstopof

activities?

Thispaperbrieflydescribesthehardwareusedtorecordthe

necessaryGPSdataandpresentsproceduresdevelopedtoidentifythekeyrecordsnecessaryto

calculateactivitydurations.Acasestudyisusedtoshowtheapplicationofthesystemtoan

earth-movingoperation.Thispaperalsopostulateshowtheinformationfromthedatacanbeused

indiscreteeventsimulations.Descrip-tionsofdiscreteeventsimulationappliedtoconstruction

opera-tionscanbefoundinMartinezandIoannou（1995）,IoannouandMartinez（1996a）,

Martinez（1998）,Sangarayakul（1998）,CorandMartinez（1999）,andIoannou（1999）.

PreviousWork

AnearlyuseofGPStocollectproductivitydatawasapilotstudydesignedtoprovidecurrent

informationregardingearthworkoperations（Ackroyd1998）.Positioninformationwastransmitted

viaradioandrecordedbyaremotePCat2-minintervalsandattheclosureofproximityswitches

onleversofarticulatedhaulersandmotorscrapers.Intheinitialphase,analysisofthedata

focusedonmeasuringcycletimes,butnorealanalysiswasperformedofpositionsbetweenevents.

Inasecondphase,straingaugeswereusedtoestimatepayloadandtherebyprovideproductivity

data.ThisworkdepictsthepotentialofGPSforrecordingdatafromearthmovingoperationsbut

focusesonthehardwareissuesratherthanthedatareductionissues.Ackroydconcludesthatthe

informationmayaddvaluetomonitoringandschedulingtasksbutdoesnotaddressuseofthedata

foranalyzingearthmovingoperations.

FieldDataReduction

Oglesbyetal.（1989）pointoutthatthepurposeofatimestudyistorecordthetimesofvarious

activitiesthatmakeupanoperation.Thesimplesttimestudies—stopwatchstudies—relyonthe

observertodecidethepointintimeatwhichactivitiesstartandstop.Oglesbyetal.（1989）note

thatplacingthisresponsibilityontheobserverlimitstheusefulnessofthedata.Observerscan

havedifferencesinopinion,datarecordedbyasingleobservermayvaryovertime,available

informationisstrictlylimitedtothatrecordedandissubjecttothephysicallimitationsofthe

observer.Additionally,theinformationrecordedisstrictlylimitedtothefieldofviewofthe

observer.

BjornssonandSagert（1994）presentedPAVIC+asacomputer-basedsystemtoextractdatafrom

videorecordingofconstructionoperations,includingactivitydurations.Eachactivityinstanceis

calledasegmentanddefinedbyastartandstoptime.Threetoolsareavailableforregistering

segments:

start-stoptime,cycletime,andconsecutivetime.Thestart-stoptimetooloperateslikea

stopwatch:

theuserindicatesthroughkeystrokesboththestartandstoptime.PAVIC+readsthe

timeofthekeystrokefromatimestampplacedontheaudiotrackandrecordsit.Thecycletime

toolisusedwhenthesameworksequenceisrepeated.Thekeystrokeusedtoindicatethestopof

anactivityalsoindicatesthestartofthesuccessiveactivity,whicheliminatestheneedtopresstwo

keyssimultaneously.Theconsecutivetimetoolisappropriateforagroupofcorrelatedactivities,

suchasacraneservingmultiplecrews.Eachactivityisassignedauniquekeythatisstruckwhen

theactivityends.Thiskeystrokeindicatesthestopoftheassociatedactivityandthestartofthe

successiveactivity.

Frank（2001）describesaverysimilarsystemusedtoextractinformationfromdigitalvideo.He

presentsanddiscussestheDigitalVideoAnalysisTool（DVAT）andnotesthatPAVIC+wasthe

basisonwhichDVATwasdeveloped.DVATisasoftwarepackagespecificallydevelopedfor

strippinginformationfromdigitalvideo.Theextractedinformationcanbeusedtogeneratecrew

balancechartsortodevelopinputforcomputersimulationmodels.

Thesetraditionaldatacollectionmethodshaverelieduponmanualtoolslimitedtothefieldof

viewoftheobserver.Researchershaveturnedtotechnologyfortoolsthatarebothautomatedand

notrestrictedtofieldofview.Kannan（1999）describestheuseofonboardinstrumentation

systemsforrecordingdatafromearthmovingoperations.Heusedmechanicalparametersrecorded

bytheVitalInformationManagementSystem（VIMS）andtheTotalPayloadManagementSystem

（TPMS）producedbyCaterpillartoobtainoperationaldata.Suchsystemsplaceavirtualobserver

intheequipment,andthustheequipmentisalwaysinthevirtualfieldofview.

Kannan（1999）statesthatwhenusingonboardinstrumentation,thesensorsmustbeabletodetect

achangeinthestatusofthetruck.Thischangeinstatusindicatesthestartorstopofanactivity.

KannanandVorster（2000）statethatmechanicalparameterscanbetranslatedtoproduction

measuresthroughtheuseofsurrogatemeasuresandprotocolrules.Kannan（1998）describesthe

useofsuspensionstrutpressure,gearcontrolleverposition,bedraiseswitchposition,andspeedto

derivethedurationoftruckcyclecomponents.Truckcyclecomponentsoractivitiesaredefinedin

termsoftheparameters.

Itisevidentfromtheliteraturereviewedthattraditionaldatacollectionmethodsarelimitedby

theabilityofanobservertoinstantaneouslydecideactivitystartandstoptimeswithinanarrow

andstaticfieldofview.Moderntechniquesremovethislimitationbyusingsensor-based

data-collectiontechniquestoidentifykeytimesthroughchangesinsensoroutput.Athorough

understandingofthemethodsforreviewing,reducing,andanalyzingGPSdatafromconstruction

operationsrequiresbackgroundknowledgeofhowandwhatdataarecollected.

DataCapture

AnautomateddatacapturesystembasedonGPStechnologywasusedtorecordtherawdataata

user-specifiedtimeinterval,includingdate,time,velocity,andhorizontalposition.Thesystem

consistsofadatabox,junctionbox,andsensorpackandwasdevelopedbasedonfieldevaluations

ofcommerciallyavailablesystems.Thedataacquisitionandstorageboxisaweathertight

enclosurethathousesthesystemcircuitryandtheCompactFlashmediaonwhichthedataisstored.

ThesensorpackconsistsofaGarminGPS-35LVCreceiverandaVector2Xmagneticcompass

manufacturedbyPrecisionNavigation,In