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简介：ＡＭＯＤＥＬＩＤＥＮＴＩＦＩＣＡＴＩＯＮＭＥＴＨＯＤＯＦＶＩＢＲＡＴＩＮＧＳＴＲＵＣＴＵＲＥＳＦＲＯＭＩＮＣＯＭＰＬＥＴＥＭＯＤＡＬＩＮＦＯＲＭＡＴＩＯＮＺｈｅｎｇＸｉａｏｐｉｎｇ（郑小平）ＹａｏＺｈｅｎｈａｎ（姚振汉）ＱｕＳｈｉｓｈｅｎｇ（蘧时胜）...

简介：Thetimedomainparameteridentificationmethodofthefoundation-structureinteractionsystemispresented.Onthebasisofbuildingthecomputationmodeandthemotionequationofthefoundation-structureinteractionsystem,thesystemparameteridentificationmethodwasestablishedbyusingtheextendedKalmanfilter(EKF)techniqueandtakingtheunknownparametersinthesystemastheaugmentstatevariables.Andthetimeparameteridentificationprocessofthefoundation-structureinteractionsystemwasimplementedbyusingthedataofthelayerfoundation-storehouseinteractionsystemmodeltestonthelargevibrationplatform.Thecomputationresultshowsthattheestablishedparameteridentificationmethodcaninducegoodparameterestmation.

简介：Pre-stackmigrationimaging(PMI)method,whichisusedingeophysicalexplorationbytheperformanceofsinglesidedetectionandvisuallydisplay,canbeusedtoidentifythelocation,orientation,andseverityofdamagesinconcretestructure.Inparticular,thisletterfocusesontheexperimentalstudybyusingafinitenumberofsensorsforfurtherpracticalapplications.Aconcretestructurewithasurface-mountedlinearPZTtransducersarrayisillustrated.Threetypesofdamages,horizontal,dippingandV-sha...

简介：Basedonthemultivariatecontinuoustimeautoregressive(CAR)model,thispaperpresentsanewtime-domainmodalidentificationmethodoflineartime-invariantsystemdrivenbytheuniformlymodulatedGaussianrandomexcitation.Themethodcanidentifythephysicalparametersofthesystemfromtheresponsedata.First,thestructuraldynamicequationistransformedintoacontinuoustimeautoregressivemodel(CAR)oforder3.Second,basedontheassumptionthattheuniformlymodulatedfunctionisapproximatelyequaltoaconstantmatrixinaveryshortperiodoftimeandonthepropertyofthestrongsolutionofthestochasticdifferentialequation,theuniformlymodulatedfunctionisidentifiedpiecewise.Twospecialsituationsarediscussed.Finally,byvirtueoftheGirsanovtheorem,weintroducealikelihoodfunction,whichisjustaconditionaldensityfunction.Maximizingthelikelihoodfunctiongivestheexactmaximumlikelihoodestimatorsofmodelparameters.Numericalresultsshowthatthemethodhashighprecisionandthecomputationiseffcient.

简介：ThispaperdealswiththeapplicationofAcousto-ultrasonics,incon-junctionwithPatternRecognitionandClassificationtechniques,totheidentificationofresidualimpactpropertiesofaclassofpolymericmaterial,namely,Polyvinylchlo-ride(PVC).PVCspecimensofdifferentlow-energyrepeatedimpactdamagestatesareprocessedbyAcousto-ultrasonics(AU)toretrieveAUsignalsintheformofdig-italizedrecords.TheseAUsignalsaregroupedasdistinctclasses,eachpertainingtoaknownlevelofrepeatedimpactdamage.DescribingfeaturesoftheseAUsignalsareusedtobuildPatternRecognition(PR)Classifiers.TheseclassifiersareusedtoidentifyunknowndamagestatesinotherPVCspecimensbyclassifyingthere-trievedAUsignalsasbelongingtooneoftheclasses.TheobtainedresultsindicatethatAcousto-ultrasonicsincombinationwithPatternRecognitionandClassificationtechniquescanbeusedforthequantitativenon-destructiveidentificationofdamagestatesinPVCspecimensofunknownlow-energyrepeatedimpactconditions.