简介:Thecriticaltechnicalproblemofunderwaterbottomobjectdetectionisfoundingastablefeaturespaceforechosignalsclassification.Thepastliteraturesmorefocusonthecharacteristicsofobjectechoesinfeaturespaceandreverberationisonlytreatedasinterference.Inthispaper,reverberationisconsideredasakindofsignalwithsteadycharacteristic,andtheclusteringofreverberationinfrequencydiscretewavelettransform(FDWT)featurespaceisstudied.Inordertoextracttheidentifyinginformationofechosignals,featurecompressionandclusteranalysisareadoptedinthispaper,andthecriterionofseparabilitybetweenobjectechoesandreverberationisgiven.TheexperimentaldataprocessingresultsshowthatreverberationhassteadypatterninFDWTfeaturespacewhichdiffersfromthatofobjectechoes.Itisproventhatthereisseparabilitybetweenreverberationandobjectechoes.
简介:Inunderwatertargetdetection,thebottomreverberationhassomeofthesamepropertiesasthetargetecho,whichhasagreatimpactontheperformance.Itisessentialtostudythedifferencebetweentargetechoandreverberation.Inthispaperbasedontheuniqueadvantageofhumanlisteningabilityonobjectsdistinction,theGammatonefilteristakenastheauditorymodel.Inaddition,time-frequencyperceptionfeaturesandauditoryspectrafeaturesareextractedforactivesonartargetechoandbottomreverberationseparation.Thefeaturesoftheexperimentaldatahavegoodconcentrationcharacteristicsinthesameclassandhavealargeamountofdifferencesbetweendifferentclasses,whichshowsthatthismethodcaneffectivelydistinguishbetweenthetargetechoandreverberation.
简介:回顾中国不同时期船长、高级船员、值班水手、值班机工以及GMDSS适任证书、"D类"证书等海员适任证书的历史沿革,并根据STCW公约马尼拉修正案履约的新要求,提出完善和改进我国海员适任证书的意见和建议。