简介：Althoughitiswellknownthatcoseismicgravitychangestakeplaceduringanearthquake,previousresearchhasnotyieldedconvincingevidencedemonstratingthatsignificantgravitychangesoccurbeforelargeearthquakes.Furthermore,evenifwesuspectthatgravitychangesoccurbeforelargeearthquakes,wehaveyettodemonstratehowtoconsistentlyobservethesechangesforusefulearthquakeforecastthatwouldbringbenefitstosociety.Weanalyzedgroundgravitysurveydataobtainedin1998,2000,2002,and2005atstationsoftheCrustalMovementObservationNetworkofChina(CMONOC)andexaminedgravitychangesbe-foretheoccurrenceofninelarge(Ms≥6.8)earthquakesthatrupturedwithinornearmainlandChinaandTaiwanfromNovember2001toAugust2008.Resultsfromthisanalysisshowthatsignificantgravitychangesoccurredacrossalargeregionbeforeeachoftheseninelargeearthquakes,andthesechangesweredetectedbyrepeatedgroundgravitysurveysthroughCMONOC.Althoughthesegravitychangesweresignificant,moreresearchisneededtoinvestigatewhetherthesegravitychangescouldbeviewedasprecursorsoflargeearthquakes.Limitationsanduncertaintiesinthedataincludesparsenessofthegravitymonitoringnetwork,longtimeintervalsbetweenconsecutivegravitysurveys,inevitablemeasurementerrors,hydrologicaleffectsongravity,andeffectsofverticalcrustalmovementsongravity.Basedontheseobservations,wemakeseveralrecommendationsaboutpossiblefuturedirec-tionsinearthquake-relatedresearchusinggravitymonitoringdata.

简介：Thispapermakesastudyontheinteractivedigitalgener-alization,wheremapgeneralizationcanbedividedintointellectivereason-ingprocedureandoperationalproce-dure,whicharedonebyhumanandcomputer,respectively.Andaninter-activemapgeneralizationenvironmentforlargescaletopographicmapisthendesignedandrealized.Thisresearchfocuseson:①thesignificanceofre-searchinganinteractivemapgenerali-zationenvironment,②thefeaturesoflargescaletopographicmapandinter-activemapgeneralization,③thecon-structionofmapgeneralization-orien-teddatabaseplatform.

简介：AnOracle8i-basedap-proachisproposedtomanagetheinte-grateddatabasesoflargeCyberCity.Thisapproachconsistsofthreeisdesignedtoacceleratespatialretrieving,inwhichtheboundingboxesoflocalregionshavenointersectionandallleafnodesoftheR+-tree(geome-tryrecords)havenorepetition;rithmsareadoptedtocompressthedigitalelevationmodels,3Dvectormodelsandimages,suchasLZ77losslesscompressionalgorithmforcompressionofvectordataandJPEGcompressionalgorithmsfortextureim-Oracle8idatabase,aCyberCityGISspatialdatabaseengine(SDE)isdesigned.OnthebasisofthisSDEpro-totypeacasestudyisdone.

简介：有EDM的GPS和高精确的距离测量的联合网络的一个新解决方案被建议。同时，它“s不妥当的仅仅使用的GPS网络与甩开大小。三个计划：陆上的网络，GPS网络和联合网络被讨论因为鉴于精确，Xiangjiaba的平面控制网设计建水坝，可靠性，详细协调并且支付。

简介：Thispaperpresentsacomponentobjectmodel(COM)basedframeworkformanaging,analyzingandvisualizingmassivemulti-scaledigitalelevationmodels(DEMs).Theframeworkconsistsofadatamanagementcomponent(DMC),whichisbasedonRDBMS/ORDBMS,adataanalysiscomponent(DAC)andadatarendercomponent(DRC).DMCcanmanagemassivemulti-scaledataexpressedatvariousreferenceframeswithinapyramiddatabaseandcansupportfastaccesstodataatvariableresolution.DACintegratesmanyusefulappliedanalyticfunctionswhoseresuitscanbeoverlaidwiththe3DscenerenderedbyDRC.DRCprovidesviewdependentdatapagingwiththesupportoftheunderlyingDMCandorganizesthepotentialvisibledataatdifferentlevelsintorendering.

简介：ThispaperreportssomeresearchesondistributionoflargevolumeimagedatausingtechniquesoftheMixedModeofJavaServletandCOMonWeb.Thearchitectureandkeytechnologiesarediscussedindetail.Thewebdistributionsystemofimageisimplementedandthesystemistestedbytheapplicationinstances.Atlast,theadvantagesanddisadvantagesforthiswebimagedistributionmodeareanalyzed.

简介：Thispaperintroducestheprocessofmaking3DvectorscenographofanancientbuildingwithlargequantitiesofdatawiththeaidofAutoCAD,whichdisplaystheeffectofscenerydrawings.ThevitalskillsandtechniqueinvolvedareillustratedthroughtheexampleofPagodaofThousandsofBuddhainChiLinNunneryinHongKong.Thisconstructionwasstartedin1996andfinishedin1999withtheconcretestructureinternalandwoodexternal,imitatingthestyleofbuildingsinTangDynasty.Thus,3Dvectorscenographbecomeavailabletousers.