简介:ADRNN(diagonalrecurrentneuralnetwork)anditsRPE(recurrentpredictionerror)learningalgorithmareproposedinthispaper.UsingofthesimplestructureofDRNNcanreducethecapacityofcalculation.TheprincipleofRPElearningalgorithmistoadjustweightsalongthedirectionofGauss-Newton.Meanwhile,itisunnecessarytocalculatethesecondlocalderivativeandtheinversematrixes,whoseunbiasednessisproved.Withapplicationtotheextremelyshorttimepredictionoflargeshippitch,satisfactoryresultsareobtained.Predictioneffectofthisalgorithmiscomparedwiththatofauto-regressionandperiodicaldiagrammethod,andcomparisonresultsshowthattheproposedalgorithmisfeasible.
简介:Inthispaperweshowthcmethodofenergyinpartwithwhichwecangetthemodelofrandomwave,andpredicttherollmotionofunstabilizedshipandstabilizedshipusingthewavemodel.Thecontrolparametersoffinstabilizeraredeterminedaccordingtotheperformanceindex.Thesimulationofthesystemisalsomadeinthispaper.Thecomparisonofthesimulationwithrealshipindicatesthatthemethodcanbeusedinthepredictionofrollmotionofastabilizedshipinrandomwave.
简介:SHIPHYDRODYNAMICSBASICRESEARCHINTHEUNITEDSTATES¥EdwinP.Rood(MechanicsandEngergyConversion(333),OfficeofNavalResearchArlington...
简介:Thesimulationofthewholeship-bridgecollisionprocesscanbeeffectivelycarriedoutbynonlineardynamicfiniteelementmethod.Basedonthesimpledescriptionofthetheory,ascenarioofa40000DWToiltankercollidingwithabridgeacrosstheYangtzeRiverisdesignedforsimulation.Thetechnologyofstructuremodelingandthedeterminationofrelatedparametersareintroduced.Thedeformationofthebulbbow,thehistoryofcollisionforcechange,theexchangeofcollisionenergyandthestressdistributionofthebridgepieraredescribedindetail,whichareofgreatvaluetobridgede-signandbridgepierdamageestimation,Somemechanicalcharactersintheprocessofship-bridgecollisionaredescribed.Moreaccurateresultscanbeproducedbyfiniteelementmethodthanthatbyempiricalformulasandsimplifiedanalyticalmethods.
简介:Theshipdesignprocessmodelisthebasisfordevelopingtheshipcollaborativedesignsystemundernetworkenvironment.Accordingtothecharacteristicsoftheshipdesign,amethodfordividingtheshipdesignprocessintothreelayersispatforward,thatisprojectlayer,designtasklayeranddesignactivitylayer,thentheformalizeddefinitionsoftheshipdesignprocessmodel,thedecomposingprinciplesoftheshipdesignprocessandthearchitectureoftheshipcollaborativedesign(SDPM)systemarepresented.Thismethodsimplifiestheactivitynetwork,makestheoptimizationandadjustmentofthedesignplanconvenientandalsomakesthedesignprocesseasiertocontrolandchange,atlastthearchitectureoftheshipcollaborativedesignsystemisdiscussed.
简介:Onthebasisofenvelopespectrumanalysisofship-radiatednoise,thefeaturesandtheextractingmethodsarediscussed,andthenanewmethodofdynamicrecognitionhasbeenproposed.Usingthismethod,accuraterecognitionratefordifferenttypesofshiptargetscanbeeffectivelyimproved,andsomeoftheimportantparametersoftarget'smovementcanbeobtainedatthesametime.
简介:Anefficientmulti-blockincompressibleviscousflowsolverbasedonsolvingtheReynolds-AveragedNavier-Stokes(RANS)equationsnumericallyhasbeendevelopedthatcanbeappliedtosimulationofavarietyofshipmaneuveringrelatedflowsandcalculationofhydrodynamicforces.Validationandverificationofthesolutionprocedurewerecarriedoutonseveralmodelproblemswithgoodagreementtoexperimentalandnumericalresults.
简介:AnewreasonablyperfectdynamicmathematicmodelhasbeenestablishedforcondenserusedinshipnuclearpowerplantaccordingtoitsstructuralfeaturesandOperatingprinciple.ThemodelhasbeensolvedbytheRunge-Kuttamethod.Andananalysisprogramhasbeendevelopedfordynamicnumericalsimulationundersteadyoperationcondition,disturbancecondi-tion,andaccidentcondition.Thedynamiccharacteristicsofcondenserhasbeencalculatedandanalyzedunderseveralkindsof
简介:BasedonthedoubleFourierintegralrepresentationforsteadyviscousshipwaves,whichinvolvesagenericamplitudefunctionandacomplexdispersionrelation,thephasefunctionforthree-dimensionalshipwavesinthefarfieldwasasymptoticallyderivedbymeansoftheLighthilltwo-stageschemecombiningtheCauchyresiduetheoremandthemethodofsteepestdescents,andtheeffectofviscosityonwavelengthswasnumericallyinvestigatedwiththeNewtoniterationmethod.Itisfoundthatthetransverseanddivergingwavesareelongatedduetothepresenceofviscosityandthelatterismoreheavilyaffectedandthatthephasedifferencesbetweentheviscoustransverseanddivergingwavesarelargerthanthoseofthecorrespondinginviscidwaves.
简介:Forsomelargelydamagedships,theconventionalmethodsareunadaptabletoestimatetheirdynamiccharacteristicsastoshipswithsymmetricalhullsection.Basedondryhullmodalanalysisofflexure-torsioncouplingvibrationofunsymmetricalshipstructuresaboutlongitudinalcenterline,atransfermatrixmethodtocalculatethedynamiccharacteristicsispresented.Takenbothsheareffectandwarpingdeformationsintoaccount,thepointandfieldtransfermatricesarederived,andtheinflu-
简介:SyntheticApertureRadar(SAR)imagingofoceansurfacefeaturesisstudied.ThesimulationoftheturbulentandvorticalfeaturesgeneratedbyamovingshipandSARimagingofthesewakesiscarriedout.Theturbulentwakedampingtheoceansurfacecapillarywavesmaybepartiallyresponsibleforthesuppressionofsurfacewavesneartheshiptrack.Thevortexpairgeneratingachangeinthelateralflowfieldbehindtheshipmaybepartiallyresponsibleforanenhancementofthewavesneartheedgesofthesmootharea.Thesehydrodynamicphenomenaaswellasthechangesofradarbackscattergeneratedbyturbulenceandvortexaresimulated.AnSARimagingmodelisthenusedonsuchoceansurfacefeaturestoprovideSARimages.Comparisonoftwoships'simulatedSARimagesshowsthatthewakefeaturesaredifferentforvariousshipparameters.
简介:TheanalysisandevaluationofanactualportsystemcontainingRdifferentship’skindsandNsubsystemseachofwhichconsistsofM.(i=1,2,…,N)portsarederived.TheexternalarrivalsofshipstothesystemcomefromRdifferentPoissonsourcesandtheinterarrivalstothequeueofeachportofasubsystemaredeterminedaccordingtoconditionprobabilities.EachporthasmultipleberthswhoseservicetimesaredistributedaccordingtoErlangprobabilitydistributionfunctions.EachportofasubsystemhasRinfinitecapacitybuffersforstoringshipsinterarrived.Thismethodprovidesagoodapproximationprocedureforobtainingsystemperfor-mancemeasuressuchaswaitingtimesofships,averagequeuelengths,etc.Optimumportcapacitycanthusbeevaluatedbyusingthisanalysis.Asimulationisalsopresentedtotestthisapproximateanalysis,andagoodagreementisobserved.Thismodelshallbeusedintheplanningofseveralactualportsystems.Throughtheapplicationofthismodel,itispossibletoanalyzeandevaluateperformancesofthesystems.
简介:Thispaperintroducesthecomposition,controlmethodandtestingresultsoftheintegratedcontrolsystemforthefirsttidalflowelectricitygenerating(TFEG)shipofChina.Thecontrolmethod,controlalgorithmandthespecificcircuitsforthehydrauliessystemarealsointroduced.Ourresearchworksareemphasizedonthecontrolalgorithmofstabilizingfrequencyandsomespecialproblemsofthecontroller.TherelatedprotectionmeasuresforhydraulicsystemandTFEGsystemhavebeentak-
简介:TherobustnessofLQGdesigningforlatitudinalmovementofshipismainlydiscussed,whenitshydrodynamicparametersfluctuatearoundcriterionvalueatrandomontheproportionaldistributing.Whenagivenshipstateatthespeedof18knandthecourseof45°underRank5stateofsea,andthehydrodynamicparametersoftheshipfluctuateatrandomontheproportionaldistributingwitharangeof±10%,±20%,±30%,therobustnessofmultivariateLQGdesigningforshipisanalyzedwithapplyingtheprobabilitymodelingofrelativecontrollingeffect.TheresultofsimulatingshowsthatwhenthehydrodynamicparametersofshipfluctuatestherelativecontrollingeffectoftheLQGdesigningsubmittonormaldistributionandthemeanvalueofrelativecontrollingeffecthasnoremarkablechangescomparingtothatwithoutperturbationofhydrodynamicparameter.