学科分类
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5 个结果
  • 简介:LFCisafunctionallanguagebasedonrecursivefunctionsdefinedincontext-freelanguages.Inthispaper,anewpatternmatchingalgorithmforLFCispresented,whichcanrepresentasequenceofpatternsasanintegerbyanencodingmethod.Itisarathersimplemethodandproducesefficientcase-expressionsforpatternmatchingdefinitionsofLFC.Thealgorithmcanalsobeusedforotherfunctionallanguages,butfornestedpatternsitmaybecomecomplicatedandfurtherstudiesareneeded.

  • 标签: 泛函语言 LFC 递归函数
  • 简介:AnimprovedtopographicdatabaseforKingGeorgeIsland,oneofthemostfrequentlyvisitedregionsinAntarctica,ispresented.AfirststepconsistedincombiningdatafromdifferentialGPSsurveysgainedduringtheaustralsummers1997~1998and1999~2000,withthecurrentcoastlinefromaSPOTsatelliteimagemosaic,topographicinformationfromexistingmapsandfromtheAntarcticDigitalDatabase.Fromthisdatasets,adigitalterrainmodel(DTM)wasgeneratedusingArc/InfoGIS.Inasecondstep,asatelliteimagemapatthescale1∶100000wasassembledfromcontourlinesderivedfromtheDTMandthesatellitemosaic.Alackofaccuratetopographicinformationintheeasternpartoftheislandwasidentified.AdditionaltopographicsurveyingorSARinterferometryshouldbeusedtoimprovethedataqualityinthatarea.TheGISintegrateddatabasewillbeindispensableforglaciologicalandclimatologicalstudiesandadministrativeandscientificpurposes.Infuture,theapplicationofGIStechniqueswillbemandatoryforenvironmentalimpactstudiesandenvironmentalmonitoringaswellasformanagementplansonKingGeorgeIsland.

  • 标签: 乔治国王岛 南极半岛 GIS 数字地面模型 卫星图象地图 冰河撤退
  • 简介:Forthepurposeofofforestation,planninganddevelopmentintheThree-NorthRegion,aseriesof6LandsatTMscenesfrom1996to1997wereusedtoclassifyland-useconditionsinthewholeKorqinSandyLandsateasternpartofInnerMongolia,China,withanareaofabout430×306squarekilometers.Lateron,Siteclassiflcationwasmadeandmappedforthe4southernsandycounties.Theannotationsymbolforeachagglomerationofsiteconditioniscomprisedofsixparts:landunit,landusepattern,soi...

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