外文文献与翻译

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1、外文文献与翻译一、文献原文：ASHORTESTPATHALGORITHMFORREALROADNETWORKBASEDONPATHOVERLAP1INTRODUCTIONAshortestpathproblemisforfindingapathwithminimumtravelcostfromoneormoreoriginstooneormoredestinationsthroughaconnectednetwork.Itisanimportantissuebecauseofitswiderangeofapplica

2、tionsintransportations.Insomeapplications,itisalsobeneficialtoknowthesecondorthirdshortestpathsbetweentwonodes.Forinstance,inordertoimprovetheeffectivenessoftravelinformationprovision,thereisaneedtoprovidesomerationalalternativepathsforroadusersdrivinginrealroa

3、dnetwork.Tomeetit,kshortestpathalgorithmshavebeenusedingeneral.Yen(1971)firstproposedkshortestpathsearchingmethod,whichcouldgenerateseveraladditionalpathsbydeletingnodeontheshortestpath.SinceYen,Severalk-shortestalgorithmshavebeensuggested.Althoughkshortestpath

4、algorithmcanprovideseveralalternativepaths,ithasinherentlimitofheavyoverlappingamongderivedpaths,whichmayleadtowrongtravelinformationtotheusers.Thisisthatsignificantproportionoflinksonthefirstpathisoverlappedbysecondandthirdpathcalculatedfromthemethod,sothedriv

5、ersonthoselinksmaysufferseverecongestionsiftheyfollowthetravelinformation.ThisisthesameproblemofIIA(IndependenceofIrrelevantAlternatives)inlogit-basedstochasticassignment.OntheotherhandexistingshortestpathalgorithmssuchasDijkstra,Moorebuildtheoptimalpathbasedon

6、thenodetheyreach.However,inthecaseofconsideringthenetworkconsistingofseveralturnprohibitionssuchasrestrictingleft-turn,whicharepopularlyadoptedinrealworldnetwork,itmakesdifficultforthetraditionalnetworkoptimizationtechniquetodealwith.Bannedandpenalizedturnsmayb

7、enotdescribedappropriatelyforinthestandardnode/linkmethodofnetworkdefinitionwithintersectionsrepresentedbynodesonly.ThereasonisthatBellman`s'PrincipleofOptimality`doesnotholdinthatcase.Severalapproacheshavebeenproposedforsolvingtheproblem.Amongallmethodscurrent

8、lyavailable,themostwidelyusedmethodisnetworkexpansionfordescribingturnpenalties,addingextranodesandextralinkstooriginalnetworkandmodifythenetworktobeeasilyimplementedtheconv