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381 个结果
  • 简介:Theresearchworkhasbeenseldomdoneaboutcloverleafjunctionexpressionina3-dimensionalcitymodel(3DCM).Themainreasonisthatthecloverleafjunctionisofteninacomplexandenormousconstruction.Itsmainbodyisbestraddleinair,andhasaerialintersectionsbetweenitsparts.Thiscomplexfeaturemadecloverleafjunctionquitedifferentfrombuildingsandterrain,therefore,itisdifficulttoexpressthiskindofspatialobjectsinthesamewayasforbuildingsandterrain.Inthispaper,authorsanalyzespatialcharacteristicsofcloverleafjunction,proposeanall-constraintpointsTINalgorithmtopartitioncloverleafjunctionroadsurface,anddevelopamethodtovisualizecloverleafjunctionroadsurfaceusingTIN.Inordertomanagecloverleafjunctiondataefficiently,theauthorsalsoanalyzedthemechanismof3DCMdatamanagement,extendedBLOBtypeinrelationaldatabase,andcombinedR-treeindextomanage3Dspatialdata.Basedonthisextension,anappropriatedatastructur

  • 标签: 3-dimensional CITY MODEL (3DCM) GIS cloverleaf
  • 简介:TheLAGFD-WAMwavemodelisathirdgenerationwavemodel.Inthepresentpaperthephysicalaspectofthemodelwasshowningreatdetailincludingenergyspectrumbalanceequation,complicatedcharacteristicsequationsandsourcefunctions.

  • 标签: normalized fitting SIMILARITY modelling BREAKING eliminating
  • 简介:Theauthorsmakeanendeavortoexplainwhyanewhybridwavemodelishereproposedwhenseveralsuchmodelshavealreadybeeninoperationandtheso-calledthirdgenerationwavemodejisprovingattractive.Thispartofthepaperisdevotedtothewindwavemodel.Bothdeepandshallowwatermodelshavebeendeveloped,theformerbeingactuallyaspecialcaseofthelatterwhenwaterdepthisgreat.Thedeepwatermodelisexceptionallysimpleinform.Significantwaveheightistheonlyprognosticvariable.Incomparisonwiththeusualmethodstocomputetheenergyinputanddissipationsempiricallyorby"tuning",theproposedmodelhasthemeritthattheeffectsofallsourcetermsarecombinedintoonetermwhichiscomputedthroughempiricalgrowthrelationsforsignificantwaves,theserelationsbeing,relativelyspeaking,easierandmorereliabletoobtainthanthoseforthesourcetermsinthespectralenergybalanceequation.Thediscretepartofthemodelandtheimplementationofthemode

  • 标签: latter compute formulate tuning ATTRACTIVE transformed
  • 简介:在黄河盆上的流速及流水量用摘要(为影响研究的提供的地区性的气候)被模仿开车由的地区性的气候模型15年(19791993)起始、侧面的边界条件和离线的大规模路由当模特儿的ECMWF分析数据(LRM)。LRM使用物理集水和河隧道信息并且允许流速及流水量与1°×为大大陆河被预言1°空间分辨率。结果证明PRECIS模型能在黄河盆上复制一般东南到降水的西北坡度分发。PRECISLRM模型联合有能力在黄河盆上模仿季节、年度的流速及流水量。模仿的流速及流水量在预定并且在大小与采纳流速及流水量通常是重合的。

  • 标签: 区域气候模型 模型确认 径流 黄河
  • 简介:Reliablequantitativeestimationofbedaggradationordegradationisimportantforriver-trainingandwatermanagementprojects.Withthedevelopmentofwaterresources,sedimentproblemsassociatedwithadamarebecomingmoresevere.Thispaperdescribessomespecialproblemsinmathematicalmodelforcalculationofdegradationandaggradationinareservoir.Themaineffortsofthisstudyareonthetreatmentofsomephysicalprocessesoffinesedimenttransport(<0.05mm).Problemsinareservoirareobviouslydifferentfromanaturalstream,suchastheturbidcurrentflow,orificesedimentflushing;andtheinitiationandconsolidationofcohesivesedimentdeposition.ThecaseofLiujiaxiaReservoir,whichislocatedintheupperreachesoftheYellowRiver,isemployedtoverifythemodel.Theresultsshowthatthemodelisapplicableintheevaluationofanengineeringplaningwithplentyoffinesedimentmovement.

  • 标签: NUMERICAL model Density current Knickpoint movement
  • 简介:Thispaperpresentsasemiparametricadjustmentmethodsuitableforgeneralcases.Assumingthattheregularizermatrixispositivedefinite,thecalculationmethodisdiscussedandthecorrespondingformulaearepresented.Finally,asimulatedadjustmentproblemisconstructedtoexplainthemethodgiveninthispaper,TheresultsfromthesemiparametricmodelandG-Mmodelarecompared.Theresultsdemonstratethatthemodelerrorsorthesystematicerrorsoftheobservationscanbedetectedcorrectlywiththesemiparametricestimatemethod.

  • 标签: 测量数据 模型误差 系统误差 半参数估计法 粗差 测量误差
  • 简介:ByusingthesimulationresultsofanAGCM,whichhadbeenrunfrom1945to1993forcedbyCOADSSST,theinterdecadalvariabilityofthemodelatmospherewasinvestigatedandcomparedwiththatofNCEPreanalysisdata.Itwasfoundthat,interdecadalvariabilityexistssignificantlyinboththetropicalPacificwindfieldsandthemid-highlatitudeatmosphericcirculationofthemodelatmosphere.Thetendencyoftimevariationandspatialdistributionsoftheinterdecadalvariabilityofthemodelatmospherearebasicallyconsistentwithobservation.Relativetothemid-highlatitudeatmosphericcirculation,thesimulationoftropicalPacificwindismoresatisfying,whichsuggeststhatanomalousvariationofSSTisstillthemainfactorfortheinterdecadalvariabilityoftropicalPacificwind.Itmighthavemoresignificantinfluenceonthetropicalwindthanonthemid-highlatitudeatmosphere.However,thereisstillobviousdifferencebetweenthesimulationandobservation.Theycouldbeattributedtoboththesimulationcapabilityofthemodelandabsenceofotherfactorsinthemodelwhichareimportantfortheinterdecadalclimatevariation.

  • 标签:
  • 简介:-Inthispaperasimpleandefficientimplicitfinite-differenceschemeisusedfordepth-averagedtwo-dimensionalstormsurgemodel.Thisfinite-differenceschemeissimplerandmoreefficientthanthewi-dely-usedADIscheme.Accuracyanalysisandstabilityanalysisindicatethattheschemehastwo-orderac-curacyandisunconditionallystablewhenthegridsizeisconstant.ThepresentanalysisresultsshowthattheschemeisofhighernumericalaccuracythanthatintroducedbyMaa(1990).Aftertestedbyidealmod-els,acalculationexampleofarealtyphoonsurgeiscarriedout,theresultsofthenumericalsimulationco-incidewellwiththeobserveddataandtheaccuracyissufficientforengineeringapplications.

  • 标签: STORM SURGE numerical simulation FINITE-DIFFERENCE scheme
  • 简介:Inordertosetupaconceptualdatamodelthatreflectstherealworldasaccuratelyaspossible,thispaperfirstlyreviewsandanalyzesthedisadvantagesofpreviousconceptualdatamodelsusedbytraditionalGISinsimulatinggeographicspace,givesanewexplanationtogeographicspaceandanalyzesitsvariousessentialcharacteristics.Finally,thispaperproposesseveraldetailedkeypointsfordesigninganewtypeofGISdatamodelandgivesasimpleholisticGISdatamodel.

  • 标签: TOPOLOGICAL RELATION LAYER GEOGRAPHIC SPACE HOLISTIC
  • 简介:RPC模型最近在摄影测量学和遥感社区提起了可观的兴趣。RPC是能够完成高近似精确性的一个概括传感器模型。不幸地,RPC模型的参数的计算服从于在所有可得到的文学的参数起始。为没有起始的价值的RPC模型的参数的计算的一个算法在SPOT-5上被介绍并且测试,CBERS-2,ERS-1imageries。RPC模型对推扫帚和SAR形象合适。

  • 标签: RPC模型 卫星图像 遥感技术 非线性
  • 简介:Anonlinearshort-wave-averaged(surfbeat)modelispresented.ThemodelisbasedonthatofRoelvink(1993),butthenumericaltechniquesusedinthesolutionarebasedontheso-calledweighted-averagedflux(WAF)method(egWatsonetal.,1992),withtime-operatorsplittingusedforthetreatmentofsomeofthesourceterms.Thismethodallowsasmallnumberofcomputationalpointstobeused,andisparticularlyefficientinmodellingbreakinglongwaves.Theshort-wave(orprimary-wave)energyequationissolvedusingamoretraditionalLax-Wendrofftechnique.Resultsofvalidationindicatethatthemodelperformssatisfactorilyinmostrespects.

  • 标签: SURF BEAT LONG WAVE SURF ZONE
  • 简介:AsimplecyclicelastoplasticconstitutivemodelforsandisproposedbasedontheUHmodelforoverconsolidatedclay.Theproposedmodelhasthefollowingfeatures.First,inordertodescribethestress-inducedanisotropyinsand,arotationalhardeningruleisintroducedfortheevolutionoftheyieldsurfaceaxiswithdevelopmentofplasticdeviatoricstrainintheprincipalstressspace.Second,therelationshipbetweentherotationalaxisandstress-inducedanisotropyismodeledbyintroducingtheslopeofrotationalaxisintotheyieldfunction.Theflatnessoftheyieldsurfacecanbedeterminedbytheslopeofrotationalaxis.Finally,arevisedunifiedhardeningparameterisproposedtoincorporatethestress-inducedanisotropy.Themodelcapabilityindescribingthecyclicresponseofsandisverifiedbycomparingthesimulationswithavailabletestresults.

  • 标签: stress-induced ANISOTROPY SAND unifi ed HARDENING
  • 简介:Inthefirstpartofthepresentpaperwehaveexplainedwhywemanagetoformulateanotherwavepredictionmodelwhensomanyofthem,includingtheso-calledthirdgenerationmodel,havealreadybeeninuse.Thewind-wavepartoftheproposedmodelhasalsobeengiven.Nowweproceedtodiscusstheswellpart,theimplementationofthemodelasapredictionmethod,mumericalexperimentsdonewithidealwindfieldsandhindcastsmadeintheBohaiSea,intheneighboringseasadjacenttoChinaandintheNorthwestPacific.

  • 标签: forecasting Bohai SWELL NORTHWEST formulate explained
  • 简介:TheperformanceofalinearresuspensionmodeldevelopedintheBalticSeawasstudiedintheconditionsofaeutrophicLakeKirkkoj(a|¨)rvi(southernFinland).Themodelpredictssedimentresuspensionrateusingdataonvegetationcover,windandsedimentqualityasaninput.Whentheoriginalmodelcoefficientswereused,themodelresultedonaverage1.8foldoverestimationoftheresuspensionrateinKirkkoj(a|¨)rvi.Thiswasduetolowerfetchandwaterdepth,andlessconsolidatedsedimentofKirkkoj(a|¨)rvicomparedwiththeBalticSeastudysite.WhencoefficientswereadjustedforKirkkoj(a|¨)rvi,themodelpredictionswere1.1timesthemeasuredvalues.Duetothecontinuousresuspension,theeffectofthewindterminthemodelwassolowthatitcouldbeexcludedwithoutaffectingtheaccuracyofmodelpredictions.Thestudydemonstratedthatinashalloweutrophiclakeaccuratepredictionsonresuspensionratecanbemadeusingonlydataonsedimentqualityandonfactorsinhibitingresuspension(macrophytes).Themodelresidualsincreasedwithincreasingresuspensionrateandhighratesofresuspensionwereunderestimatedbythemodel.DuetothefluffysedimentinKirkkoj(a|¨)rvi,erosionofsedimentincreasesmorethanlinearwithincreasingshearstress.Thusinsuchconditions,evenbetterpredictionscouldbeachievedbyanon-linearresuspensionmodel.

  • 标签: 应用模型 波罗的海 性能差异 再悬浮 湖泊富营养化 富营养化湖泊
  • 简介:A2-Dslab-symmetricmodelofmixedconvective-stratiformcloudisdevelopedbysuperimposingconvectivecloud-sizefieldontheconvergencefield,inordertosimulateandstudythemixedcloudsconsistingofstratiformcloudandconvectivecloud.Adeepconvective,anelasticandconservativesystemofequationswithbasicvariables(V,θ,π’)issolvedbyanewmethodtocalculatedynamicfield.Thewatersubstanceinthecloudisdividedinto6categoriesandthemicrophysicalprocessesaredescribedinspectrumwithtwovariableparametersandmorereasonableparticlenumber/sizedistributions.Tocomparewithmeasuredradarechointensityandstructure,themodelmaycalculateechointensityofthemodelcloudobservedbyradar.

  • 标签: convective-stratiform MIXED cloud NUMERICAL model particle
  • 简介:Inthispaper,thej,υcorrectedformulaeoftheamplitudesandthephasesof58astronomicalconstituentsaregiven,andthemodelsfortheanalysisandpredictionof169constituentsarepresented.ThenewCartwright’scalculatedresultsofthetidalpotentialareused,andthequadraticanalysisismade.Ithasbeenprovedbyanumberoftrialsthattheharmonicconstantsofconstituentsaremorestableandtheaccuracyofthepredictedresultreliable.

  • 标签: TIDES A J TIDAL corrected FORMULAE
  • 简介:BinomialmodelonseismicriskanalysisJianWANG(王健)andZhen-LiangSHI(时振梁)(InstituteofGeophysics,StateSeismologicalBureau,Beijing100...

  • 标签: SEISMIC UNCERTAINTY BINOMIAL MODEL SEISMIC RISK