简介:LFCisafunctionallanguagebasedonrecursivefunctionsdefinedincontext-freelanguages.Inthispaper,anewpatternmatchingalgorithmforLFCispresented,whichcanrepresentasequenceofpatternsasanintegerbyanencodingmethod.Itisarathersimplemethodandproducesefficientcase-expressionsforpatternmatchingdefinitionsofLFC.Thealgorithmcanalsobeusedforotherfunctionallanguages,butfornestedpatternsitmaybecomecomplicatedandfurtherstudiesareneeded.
简介:AnimprovedtopographicdatabaseforKingGeorgeIsland,oneofthemostfrequentlyvisitedregionsinAntarctica,ispresented.AfirststepconsistedincombiningdatafromdifferentialGPSsurveysgainedduringtheaustralsummers1997~1998and1999~2000,withthecurrentcoastlinefromaSPOTsatelliteimagemosaic,topographicinformationfromexistingmapsandfromtheAntarcticDigitalDatabase.Fromthisdatasets,adigitalterrainmodel(DTM)wasgeneratedusingArc/InfoGIS.Inasecondstep,asatelliteimagemapatthescale1∶100000wasassembledfromcontourlinesderivedfromtheDTMandthesatellitemosaic.Alackofaccuratetopographicinformationintheeasternpartoftheislandwasidentified.AdditionaltopographicsurveyingorSARinterferometryshouldbeusedtoimprovethedataqualityinthatarea.TheGISintegrateddatabasewillbeindispensableforglaciologicalandclimatologicalstudiesandadministrativeandscientificpurposes.Infuture,theapplicationofGIStechniqueswillbemandatoryforenvironmentalimpactstudiesandenvironmentalmonitoringaswellasformanagementplansonKingGeorgeIsland.
简介:Forthepurposeofofforestation,planninganddevelopmentintheThree-NorthRegion,aseriesof6LandsatTMscenesfrom1996to1997wereusedtoclassifyland-useconditionsinthewholeKorqinSandyLandsateasternpartofInnerMongolia,China,withanareaofabout430×306squarekilometers.Lateron,Siteclassiflcationwasmadeandmappedforthe4southernsandycounties.Theannotationsymbolforeachagglomerationofsiteconditioniscomprisedofsixparts:landunit,landusepattern,soi...