简介:Theresearchworkhasbeenseldomdoneaboutcloverleafjunctionexpressionina3-dimensionalcitymodel(3DCM).Themainreasonisthatthecloverleafjunctionisofteninacomplexandenormousconstruction.Itsmainbodyisbestraddleinair,andhasaerialintersectionsbetweenitsparts.Thiscomplexfeaturemadecloverleafjunctionquitedifferentfrombuildingsandterrain,therefore,itisdifficulttoexpressthiskindofspatialobjectsinthesamewayasforbuildingsandterrain.Inthispaper,authorsanalyzespatialcharacteristicsofcloverleafjunction,proposeanall-constraintpointsTINalgorithmtopartitioncloverleafjunctionroadsurface,anddevelopamethodtovisualizecloverleafjunctionroadsurfaceusingTIN.Inordertomanagecloverleafjunctiondataefficiently,theauthorsalsoanalyzedthemechanismof3DCMdatamanagement,extendedBLOBtypeinrelationaldatabase,andcombinedR-treeindextomanage3Dspatialdata.Basedonthisextension,anappropriatedatastructur
简介:TheLAGFD-WAMwavemodelisathirdgenerationwavemodel.Inthepresentpaperthephysicalaspectofthemodelwasshowningreatdetailincludingenergyspectrumbalanceequation,complicatedcharacteristicsequationsandsourcefunctions.
简介:Theauthorsmakeanendeavortoexplainwhyanewhybridwavemodelishereproposedwhenseveralsuchmodelshavealreadybeeninoperationandtheso-calledthirdgenerationwavemodejisprovingattractive.Thispartofthepaperisdevotedtothewindwavemodel.Bothdeepandshallowwatermodelshavebeendeveloped,theformerbeingactuallyaspecialcaseofthelatterwhenwaterdepthisgreat.Thedeepwatermodelisexceptionallysimpleinform.Significantwaveheightistheonlyprognosticvariable.Incomparisonwiththeusualmethodstocomputetheenergyinputanddissipationsempiricallyorby"tuning",theproposedmodelhasthemeritthattheeffectsofallsourcetermsarecombinedintoonetermwhichiscomputedthroughempiricalgrowthrelationsforsignificantwaves,theserelationsbeing,relativelyspeaking,easierandmorereliabletoobtainthanthoseforthesourcetermsinthespectralenergybalanceequation.Thediscretepartofthemodelandtheimplementationofthemode
简介:Reliablequantitativeestimationofbedaggradationordegradationisimportantforriver-trainingandwatermanagementprojects.Withthedevelopmentofwaterresources,sedimentproblemsassociatedwithadamarebecomingmoresevere.Thispaperdescribessomespecialproblemsinmathematicalmodelforcalculationofdegradationandaggradationinareservoir.Themaineffortsofthisstudyareonthetreatmentofsomephysicalprocessesoffinesedimenttransport(<0.05mm).Problemsinareservoirareobviouslydifferentfromanaturalstream,suchastheturbidcurrentflow,orificesedimentflushing;andtheinitiationandconsolidationofcohesivesedimentdeposition.ThecaseofLiujiaxiaReservoir,whichislocatedintheupperreachesoftheYellowRiver,isemployedtoverifythemodel.Theresultsshowthatthemodelisapplicableintheevaluationofanengineeringplaningwithplentyoffinesedimentmovement.
简介:Thispaperpresentsasemiparametricadjustmentmethodsuitableforgeneralcases.Assumingthattheregularizermatrixispositivedefinite,thecalculationmethodisdiscussedandthecorrespondingformulaearepresented.Finally,asimulatedadjustmentproblemisconstructedtoexplainthemethodgiveninthispaper,TheresultsfromthesemiparametricmodelandG-Mmodelarecompared.Theresultsdemonstratethatthemodelerrorsorthesystematicerrorsoftheobservationscanbedetectedcorrectlywiththesemiparametricestimatemethod.
简介:ByusingthesimulationresultsofanAGCM,whichhadbeenrunfrom1945to1993forcedbyCOADSSST,theinterdecadalvariabilityofthemodelatmospherewasinvestigatedandcomparedwiththatofNCEPreanalysisdata.Itwasfoundthat,interdecadalvariabilityexistssignificantlyinboththetropicalPacificwindfieldsandthemid-highlatitudeatmosphericcirculationofthemodelatmosphere.Thetendencyoftimevariationandspatialdistributionsoftheinterdecadalvariabilityofthemodelatmospherearebasicallyconsistentwithobservation.Relativetothemid-highlatitudeatmosphericcirculation,thesimulationoftropicalPacificwindismoresatisfying,whichsuggeststhatanomalousvariationofSSTisstillthemainfactorfortheinterdecadalvariabilityoftropicalPacificwind.Itmighthavemoresignificantinfluenceonthetropicalwindthanonthemid-highlatitudeatmosphere.However,thereisstillobviousdifferencebetweenthesimulationandobservation.Theycouldbeattributedtoboththesimulationcapabilityofthemodelandabsenceofotherfactorsinthemodelwhichareimportantfortheinterdecadalclimatevariation.
简介:-Inthispaperasimpleandefficientimplicitfinite-differenceschemeisusedfordepth-averagedtwo-dimensionalstormsurgemodel.Thisfinite-differenceschemeissimplerandmoreefficientthanthewi-dely-usedADIscheme.Accuracyanalysisandstabilityanalysisindicatethattheschemehastwo-orderac-curacyandisunconditionallystablewhenthegridsizeisconstant.ThepresentanalysisresultsshowthattheschemeisofhighernumericalaccuracythanthatintroducedbyMaa(1990).Aftertestedbyidealmod-els,acalculationexampleofarealtyphoonsurgeiscarriedout,theresultsofthenumericalsimulationco-incidewellwiththeobserveddataandtheaccuracyissufficientforengineeringapplications.
简介:Inordertosetupaconceptualdatamodelthatreflectstherealworldasaccuratelyaspossible,thispaperfirstlyreviewsandanalyzesthedisadvantagesofpreviousconceptualdatamodelsusedbytraditionalGISinsimulatinggeographicspace,givesanewexplanationtogeographicspaceandanalyzesitsvariousessentialcharacteristics.Finally,thispaperproposesseveraldetailedkeypointsfordesigninganewtypeofGISdatamodelandgivesasimpleholisticGISdatamodel.
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.
简介:AsimplecyclicelastoplasticconstitutivemodelforsandisproposedbasedontheUHmodelforoverconsolidatedclay.Theproposedmodelhasthefollowingfeatures.First,inordertodescribethestress-inducedanisotropyinsand,arotationalhardeningruleisintroducedfortheevolutionoftheyieldsurfaceaxiswithdevelopmentofplasticdeviatoricstrainintheprincipalstressspace.Second,therelationshipbetweentherotationalaxisandstress-inducedanisotropyismodeledbyintroducingtheslopeofrotationalaxisintotheyieldfunction.Theflatnessoftheyieldsurfacecanbedeterminedbytheslopeofrotationalaxis.Finally,arevisedunifiedhardeningparameterisproposedtoincorporatethestress-inducedanisotropy.Themodelcapabilityindescribingthecyclicresponseofsandisverifiedbycomparingthesimulationswithavailabletestresults.
简介:Inthefirstpartofthepresentpaperwehaveexplainedwhywemanagetoformulateanotherwavepredictionmodelwhensomanyofthem,includingtheso-calledthirdgenerationmodel,havealreadybeeninuse.Thewind-wavepartoftheproposedmodelhasalsobeengiven.Nowweproceedtodiscusstheswellpart,theimplementationofthemodelasapredictionmethod,mumericalexperimentsdonewithidealwindfieldsandhindcastsmadeintheBohaiSea,intheneighboringseasadjacenttoChinaandintheNorthwestPacific.
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.
简介:A2-Dslab-symmetricmodelofmixedconvective-stratiformcloudisdevelopedbysuperimposingconvectivecloud-sizefieldontheconvergencefield,inordertosimulateandstudythemixedcloudsconsistingofstratiformcloudandconvectivecloud.Adeepconvective,anelasticandconservativesystemofequationswithbasicvariables(V,θ,π’)issolvedbyanewmethodtocalculatedynamicfield.Thewatersubstanceinthecloudisdividedinto6categoriesandthemicrophysicalprocessesaredescribedinspectrumwithtwovariableparametersandmorereasonableparticlenumber/sizedistributions.Tocomparewithmeasuredradarechointensityandstructure,themodelmaycalculateechointensityofthemodelcloudobservedbyradar.
简介:Inthispaper,thej,υcorrectedformulaeoftheamplitudesandthephasesof58astronomicalconstituentsaregiven,andthemodelsfortheanalysisandpredictionof169constituentsarepresented.ThenewCartwright’scalculatedresultsofthetidalpotentialareused,andthequadraticanalysisismade.Ithasbeenprovedbyanumberoftrialsthattheharmonicconstantsofconstituentsaremorestableandtheaccuracyofthepredictedresultreliable.