简介:Syntheticapertureradarinterferometry(InSAR)hasbeenusedasaninnovativetechniquefordigitalelevationmodel(DEM)andtopographicmapgeneration.Inthispaper,externalDEMsareusedforInSARDEMgenerationtoreducetheerrorsindataprocessing.TheDEMsgeneratedfromrepeat-passInSARarecompared.Forsteepslopesandseverechangesintopography,phaseunwrappingqualitycanbeimprovedbysubtractingthephasecalculatedfromanexternalDEM.ItisaffirmativethattheabsoluteheightaccuracyoftheInSARDEMisimprovedbyusingexternalDEM.Thedataprocessingwasundertakenwithouttheuseofgroundcontrolpointsandothermanualoperation.
简介:在严肃下面的自发的粒子过滤的现象借助于分离元素方法被调查。象过滤速度,住处时间分发和光线的分散那样的过滤行为在各种各样的条件下面被检验。经过一包更大的粒子移动的一个滤粒子的垂直速度与增加在粒子和滤到包装粒子的直径比率之间的归还系数减少,这被显示出。随归还系数的增加,住处时间和滤粒子的光线的分散增加。收拾行李的高度影响住处时间和光线的分散。但是,效果能在他们分别地到平均住处时间和收拾行李的高度和收拾行李的粒子直径的产品被使正常化的住处时间和光线的分散的分析被消除。另外,当额外的经常的垂直力量被使用时,过滤速度被显示与滤粒子的垂直加速有关。增加滤的喂的率粒子减少分散系数。
简介:摘要数字高程模型(DigitalElevationModel,DEM)的数据源,可采用数字地形图的等高线等数据及野外实测数据或原有纸质地形图数字化数据。本文对VirtuoZoNT系统下如何提高DEM数据有效性的作业方法及核实DEM精度采取适当的检验方法做出阐述。
简介:Weintroducetwoimprovementsinthenumericalschemetosimulatecollisionandslowshearingofirregularparticles.First,weproposeanalternativeapproachbasedonsimplerelationstocomputethefrictionalcontactforces.TheapproachimprovesefficiencyandaccuracyoftheDiscreteElementMethod(DEM)whenmodelingthedynamicsofthegranularpacking.Wedeterminetheproperupperlimitfortheintegrationstepinthestandardnumericalschemeusingawiderangeofmaterialparameters.Tothisend,westudythekineticenergydecayinastresscontrolledtestbetweentwoparticles.Second,weshowthattheusualwayofdefiningthecontactplanebetweentwopolygonalparticlesis,ingeneral,notuniquewhichleadstodiscontinuitiesinthedirectionofthecontactplanewhileparticlesmove.Tosolvethisdrawback,weintroduceanaccuratedefinitionforthecontactplanebasedontheshapeoftheoverlapareabetweentouchingparticles,whichevolvescontinuouslyintime.
简介:Thispaperdevelopsamethodwhichcanbeusedtoassistaerialnavigationbydeterminingthespatialpositionandpostureoftheaerialphotographicplane.Afterthemethod,aerialimagesmatchknownDEMtocapturethespatialpositionandposture.Someaerialimagesandterraindataareusedtotestifyourmethod.Comparedwiththoseofanalyticandstereomappers,theresultsbyourmethodarecorrespondenttorealmeasurementswell.
简介:本文讨论了DEM、DOM生产中遇到的一些问题,并对这些问题提出一些解决方法,可供生产单位借鉴。