无线传感器网络中英文对照外文翻译文献.docx
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中英文对照外文翻译文献
(文档含英文原文和中文翻译)
原文:
Distributedlocalizationinwirelesssensornetworks:
aquantitativecomparison
ABSTRACT
Thispaperstudiestheproblemofdeterminingthenodelocationsinad-hocsensornetworks.Wecomparethreedistributedlocalizationalgorithms(Ad-hocpositioning,Robustpositioning,andN-hopmultilateration)onasinglesimulationplatform.Thealgorithmsshareacommon,three-phasestructure:
(1)
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determinenode–anchordistances,
(2)computenodepositions,and(3)optionallyrefinethepositionsthroughaniterativeprocedure.Wepresentadetailedanalysiscomparingthevariousalternativesforeachphase,aswellasahead-to-headcomparisonofthecompletealgorithms.Themainconclusionisthatnosinglealgorithmperformsbest;whichalgorithmistobepreferreddependsontheconditions(rangeerrors,connectivity,anchorfraction,etc.).Ineachcase,however,thereissignificantroomforimprovingaccuracyand/orincreasing
coverage
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INTRODUCTION
Wirelesssensornetworksholdthepromiseofmanynewapplicationsinthe
areaofmonitoringandcontrol.Examplesincludetargettracking,intrusiondetection,wildlifehabitatmonitoring,climatecontrol,anddisastermanagement.Theunderlyingtechnologythatdrivestheemergenceofsensorapplicationsistherapiddevelopmentintheintegrationofdigitalcircuitry,whichwillbringussmall,cheap,autonomoussensornodesinthenearfuture.
Newtechnologyoffersnewopportunities,butitalsointroducesnewproblems.Thisisparticularlytrueforsensornetworkswherethecapabilitiesofindividualnodesareverylimited.Hence,collaborationbetweennodesisrequired,butenergyconservationisamajorconcern,whichimpliesthatcommunicationshouldbeminimized.Theseconflictingobjectivesrequire
unorthodoxsolutionsformanysituations.
ArecentsurveybyAkyildizetal.discussesalong
issuesthatmustbeaddressedbeforesensornetworksdeployed.Theproblemsrangefromthephysicallayer
listofopenresearch
canbecomewidely(low-powersensing,
processing,andcommunicationhardware)allthewayuptotheapplicationlayer(queryanddatadisseminationprotocols).Inthispaperweaddresstheissueoflocalizationinad-hocsensornetworks.Thatis,wewanttodeterminethelocationofindividualsensornodeswithoutrelyingonexternalinfrastructure
(basestations,satellites,etc.).
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Thelocalizationproblemhasreceivedconsiderableattentioninthepast,asmanyapplicationsneedtoknowwhereobjectsorpersonsare,andhencevariouslocationserviceshavebeencreated.Undoubtedly,theGlobalPositioningSystem(GPS)isthemostwell-knownlocationserviceinusetoday.TheapproachtakenbyGPS,however,isunsuitableforlow-cost,ad-hocsensornetworkssinceGPSis based on extensive infrastructure (i.e., satellites). Likewise solutionsdevelopedintheareaofroboticandubiquitouscomputingaregenerallynotapplicableforsensornetworksastheyrequiretoomuchprocessingpowerandenergy.
Recentlyanumberoflocalizationsystemshavebeenproposedspecificallyforsensornetworks.Weareinterestedintrulydistributedalgorithmsthatcanbeemployedonlarge-scalead-hocsensornetworks(100+nodes).Suchalgorithmsshouldbe:
•self-organizing(i.e.,donotdependonglobalinfrastructure),
•robust(i.e.,betoleranttonodefailuresandrangeerrors),
•energyefficient(i.e.,requirelittlecomputationand,especially,communication).
Theserequirementsimmediatelyruleoutsomeoftheproposedlocalizationalgorithmsforsensornetworks.Wecarriedoutathoroughsensitivityanalysisonthreealgorithmsthatdomeettheaboverequirementstodeterminehowwelltheyperformundervariousconditions.Inparticular,westudiedtheimpactofthefollowingparameters:
rangeerrors,connectivity (density),andanchorfraction.Thesealgorithmsdifferintheirpositionaccuracy,networkcoverage,inducednetworktraffic,andprocessorload.Giventhe(slightly)differentdesignobjectivesforthethreealgorithms,itisnosurprisethateachalgorithmoutperformstheothersunderaspecificsetofconditions.Undereachcondition,however,eventhebestalgorithmleavesmuchroomforimprovingaccuracyand/orincreasingcoverage.
Themaincontributionsofourworkdescribedinthispaperare:
•weidentifyacommon,three-phase,structureinthedistributedlocalization
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algorithms.
•weidentifyagenericoptimizationapplicabletoallalgorithms.
•weprovideadetailedcomparisononasingle(simulation)platform.
•weshowthatthereisnoalgorithmthatperformsbest,andthatthereexistsroomforimprovementinmostcases.
Section2discussestheselection,genericstructure,andoperationofthreedistributedlocalizationalgorithmsforlarge-scalead-hocsensornetworks.Thesealgorithmsarecomparedonasimulationplatform,whichis