学科分类
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180 个结果
  • 简介:Theestuaryandcoastisanareawherethelandandtheseainteractandaplaceinwhichhumanbeingsfrequentlymoveaboutsothatunderstandingandcontrollingthechangeanddevelopmentmodesofthecoastallandformplaysavitalpartinexploitingandprotectingcoastalresources.Amodelisthegeneralizationandabstractionofobjectivethings.Thispapersummarizesfourmethodsforthelandformdevelopmentofthetidalshoreandunderwaterdelta,mainlydiscussesthemodel'sstructuralelements,andpresentstheirspecificapplicationonthebasisoftheauthors'casestudy.Withtheapplicationoftheprofilemodel,thedynamicchangeofcoastallandformcanbeclearlyseenbycontrastingthedifferentprofilesofdifferentyears.Throughtheshrinking,expandingandtransformationoftheisobath,planemodelisusedtostudythemacro-changeoftheshoalandthecoastallandform.Speedmodelisanefficientmeanstoanalyzethetrendoferosionanddepositionandthelocalchangeinagreatareaofthesea.Statisticalsurveymodelisastaticanalysis,whichcanbeusedtoestablishtherelationshipbetweentheerosionanddepositionoftheshoalandthealtitudeandslopeofsurveyspot.

  • 标签: 剖面模型 速度模型 统计测量 扬子江河口 海岸保护 沉积性质
  • 简介:首先利用支持向量机(SVM)和人工神经网络(ANN)对Landsat8OLI多光谱影像进行基于光谱信息的土地利用监督分类;然后,对多波段进行主成分变换,提取第一主成分的主要纹理信息,与光谱信息一起进行融合光谱和纹理信息的SVM和ANN影像监督分类.对比分析发现:对中原地区,SVM是Landsat8多光谱遥感影像分类的较优方法,尤其适用于农业用地信息提取;光谱分类即可达到较高精度,纹理信息对提高分类精度的作用十分有限.

  • 标签: 多光谱遥感 影像分类 支持向量机 人工神经网络 纹理
  • 简介:“亚特兰特”海洋调查船为目前世界上最先进的调查船之一。除在法国管辖海域进行海洋调查活动以外,还在世界各海区与有关国家合作,进行海洋科技调查。该船1996年4月22日至5月20日与我国国家海洋局一所、二所合

  • 标签: 海洋调查船 接收器 INMARSAT 兰特 海洋科技 工作水深
  • 简介:针对海底采样点较少时,监督学习训练分类模型困难的问题,研究无监督学习的K-均值聚类分析算法在多波束海底底质分类的应用。在探讨K-均值聚类分析算法原理的基础上,构建海底底质分类器,针对分类器需预先输入分类结果种类(K值)这一问题,提出了基于底质采样点和分类效果连续性为原则的K值确定方法。实验结果表明:基于K-均值聚类分析算法的海底底质分类器能较好的实现海底底质类型的自动划分,适用于海量多波束底质特征参数的分类

  • 标签: 多波束测量 海底底质分类 特征参数 K-均值算法 聚类分析
  • 简介:ExplosionforthetreatmentofunderwatersoftfoundationisatechniquenewlydevelopedinChina.ThispaperdescribestheapplicationofthemethodofexplosiontounderwatersoftfoundationtreatmentoftheGreat-WestDyke,LianyungangPort,includingthetechnicalcharacteristicsandtheeffect,selectionofexplosionparameters,workmanshipofconstruction,requirementsofqualityandinspection,andthelike.

  • 标签: Explosion SOFT FOUNDATION TREATMENT DYKE
  • 简介:NeomysisawatschensiswascollectedonthewestcoastofJiaozhouBay,Qingdaoin1992andacclimatedinthelaboratoryconditions.Theacutetoxicitymethodusing4~6dayjuvenilemysidofthisspeciesisstudied.ThespeciesiscomparedwithM.bahiaintaxonomy,geographicdistribution,morphology,aswellasthesensitivitytoAbstracttoxins.Basedontheresults,werecommendN.awatschensistobeastandardmarineorganismfortoxicitytestinChinaandthemethodtobeappliedintoxicityevaluationofdrillingfluids.Inthispaper,wereporttheresultsoftheabovestudiesandtheapplicationofthemethodintheevaluationofseveraldrillingfluidproducts.

  • 标签: 毒素 毒性 矿物 标准有机物 钻探泥浆 胶洲湾
  • 简介:Metalpollutioninaquaticecosystemsisofimmenseimportance.Undervariousenvironmentcircumstances,themetalcontentsofsedimentscanenterintotheoverlyingwaterbodyleadingtoseveretoxicity.ThisstudyaimstodeterminemetalconcentrationsinsedimentsofAnzaliInternationalWetlandinIran.Chemicalpartitioningmethodisusedtodeterminetheportionofanthropogenicpollutionandthemobilitypotentialofeachmetal.Theintensityofmetalpollutioninsedimentsofthewetlandisassessedusingthreereliableindices.TheresultsofchemicalpartitioningrevealthatcadmiumbearthehighestriskofbeingreleasedintotheaquaticenvironmentandhighamountofmanganeseinsulfidebondphaseimpliestheinitiationofredoxstateinaquaticenvironmentoftheAnzaliWetland.TheresultsofchemicalpartitioningstudiesshowthatPb,Cd,MnandAshavethehighestanthropogenicportion.Clusteranalysisalsoconfirmstheresultsofchemicalpartitioningandindicatesthatthementionedmetalscanbeoriginatedfromanthropogenicsources.Sedimentpollutionindices,including,I_geo,I_POLL,andm-ERM-Qrevealthatmetalsareintherangeoflowtomoderatepollutionandalsoshowthatthehighestmetalpollutionisintheeasternandcentralpartsofthewetland.Thiscanbeascribedtoriverswhicharetherecipientofindustrial,agriculturalandmunicipalwastewatersandflowintothesepartsofthewetland.

  • 标签: 重金属污染 湿地水环境 化学分类法 污染指数 沉积物 评估
  • 简介:OwingtotheBenjamin-Feirinstability,theStokeswavetrainexperiencesamodulation-demodulationprocess,andpresentsarecurrencecharacteristics.StiassnieandShemerresearchedtheunstableevolutionprocessandprovidedatheoreticalformulationfortherecurrenceperiodin1985onthebasisofthenonlinearcubicSchrdingerequation(NLS).However,NLShaslimitationsonthenarrowbandandtheweaknonlinearity.Therecurrenceperiodisre-investigatedinthispaperbyusingahighlyefficientHighOrderSpectral(HOS)method,whichcanbeappliedforthedirectphaseresolvedsimulationofthenonlinearwavetrainevolution.ItisfoundthattheStiassnieandShemer’sformulashouldbemodifiedinthecaseswithmostunstableinitialconditions,whichisimportantforsuchtopicsasthegenerationmechanismsoffreakwaves.AnewrecurrenceperiodformulaispresentedandsomenewevolutioncharacteristicsoftheStokeswavetrainarealsodiscussedindetails.

  • 标签: STOKES波 复发期 高阶谱 列车 非线性薛定谔方程 谱方法
  • 简介:AnewanalyticalmethodusingBack-Propagation(BP)artificialneuralnetworkandkineticspectrophotometryforsimultaneousdeterminationofironandmagnesiumintapwater,theYellowRiverwaterandseawaterisestablished.Byconditionalexperiments,theoptimumanalyticalconditionsandparametersareobtained.Levenberg-Marquart(L-M)algorithmisusedforcalculationinBPneuralnetwork.Thetopologicalstructureofthree-layerBPANNnetworkarchitectureischosenas15-16-2(nodes).Theinitialvalueofgradientcoefficientμisfixedat0.001andtheincreasefactorandreductionfactorofμtakethedefaultvaluesofthesystem.ThedataareprocessedbycomputerswithourownprogramswritteninMATLAB7.0.Therelativestandarddeviationofthecalculatedresultsforironandmanganeseis2.30%and2.67%respectively.Theresultsofstandardadditionmethodshowthatforthetapwater,therecoveriesofironandmanganeseareintherangesof98.0%-104.3%and96.5%-104.5%,andtheRSDisintherangeof0.23%-0.98%;fortheYellowRiverwater(LijindistrictofShandongProvince),therecoveriesofironandmanganeseareintherangesof96.0%-101.0%and98.7%-104.2%,andtheRSDisintherangeof0.13%-2.52%;fortheseawaterinQingdaooffshore,therecoveriesofironandmanganeseareintherangesof95.3%-104.8%and95.3%-104.7%,andtheRSDisintherangeof0.14%-2.66%.Itisfoundthat21commoncationsandanionsdonotinterferewiththedeterminationofironandmanganeseundertheoptimumexperimentalconditions.Thismethodexhibitsgoodreproducibilityandhighaccuracyinthedeterminationofironandmanganeseandcanbeusedforthesimultaneousdeterminationofironandmanganeseintapwaterandnaturalwater.ByusingtheestablishedANN-catalyticspectrophotometricmethod,theironandmanganeseconcentrationsofthesurfaceseawaterat11sitesinQingdaooffshorearedeterminedandtheleveldistributionmapsofironandmanganesearedrawn.

  • 标签: 人工神经网络 催化分光光度法 光度法测定 自来水 Marquardt BP神经网络
  • 简介:国际海道测量组织是海道测量领域全球唯一的国际性、政府间、技术咨询组织,长期主导着标准和技术的发展方向,先后发布了多种出版物.研究了IHO出版物的分类、出版物主要内容,分析了IHO出版物的发展趋势,最后提出了相关的工作建议.

  • 标签: 国际海道测量组织 出版物 出版物分类
  • 简介:Full-rangenonlinearanalysisoffatiguebehaviorsofreinforcedconcretestructuresbyfiniteelementmethod¥SongYupu;ZhaoShunbo;WangRuim...

  • 标签: REINFORCED CONCRETE structures FATIGUE behavior full-range
  • 简介:Themovingparticlesemi-implicit(MPS)methodhasdemonstrateditsusefulnessinpracticalengineeringapplications.Althoughithaswideapplicability,itisstillhardtopredictthepressurepreciselyusingtheMPSmethod.Apressure-convectionparticlemethodbasedontheMPSmethodisproposedtoovercomethisproblem.Theimprovedperformanceofthisnewmethodisvalidatedwithcomputationalandmeasuredresults.Theapproachisalsoappliedtocomputetheproblemofsloshingassociatedwithfloatingbodymotioninwaves.Thepressure-convectionMPSmethoddemonstrateditscapabilitytoimprovethepredictionofpressure.

  • 标签: 压力预测 浮体运动 粒子法 对流 数值模拟 部分填充
  • 简介:Ninesamplesofsuspendedmatteratthesurfaceorbottomand34elementsin20samplesofsubstratesedimenthavebeenusedintheneutronactivationanalyses.Authorsstudysedimentandsuspendedmattermovementbyusingthemethodofelementgeochemistry,andconcludethroughsyntheticanalysisandprocessingthatthemovementdirectionofsuspendedmatterandsubstratesedimenttendstoconvergeonthecentralarea.

  • 标签: NEUTRON activation analysis element GEOCHEMISTRY SEDIMENT
  • 简介:基于相关矩阵特征向量的目标分解将地物回波复杂的散射过程分解成相互独立的三种单一散射分量:单向散射、双向散射和交叉散射,分别对应各自的目标相关矩阵.目标分解技术降低了散射回波之间的相关性,有利于分析地物散射机理,有助于提高分类精度.对荷兰Flevoland地区全极化数据进行分解,经过试验和相关性分析,选用7种数据形成多参数数据组合,对其进行最大似然监督分类,同时进行常规三种极化加相位差的分类和基于复Wishart分布的最大似然分类,逐像元计算混淆矩阵,分析对比三种分类结果的精度,试验表明:相对于常规数据组合分类,基于复Wishart分布的监督分类可以小幅度提高分类精度,而利用目标分解得到多参数组合数据进行分类则有大幅度的提高。

  • 标签: 全极化 目标分解 分类 精度
  • 简介:新版渔业用在数学基础的确定、表示的主要内容和生产方式上都发生了一定变化,针对新版渔业用的设计特点,介绍了其表示的主要内容、数据结构设计以及版面设计方法.

  • 标签: 渔业用图 数学基础 分幅 表示内容 数据结构 版面
  • 简介:侧扫纳最终的扫测结果是以声的形式呈现在使用者面前,而声与平时我们大家所熟悉的照片有很大的不同,不能反映物体的真实形状,只能用灰度来反映物体的强与弱,所以在实际应用,大家感到最困难的是声的判读,特别是对刚接触侧扫声纳的使用人员来说,声判读更是一件棘手的事.其实任何事物都有其规律,我们只要了解声图形成、结构和特点,掌握声判别的基本方法,通过实践,大家都可以成为一个判的高手.

  • 标签: 侧扫 图判别 声纳图
  • 简介:AnovelmodelingtechniquebasedonthecoupledEulerian-Lagrangian(CEL)methodisprovidedtosolvethegeotechnicalproblemswithlargedeformations.Thetechniqueisintendedtosolvetheupdateproblemofsoilmechanicalpropertiesduringspudcanpenetrationinnormallyconsolidatedclaysoil.IntheCELmodel,thenormalmethodofassigninganincreasingshearstrengthprofilewithdepth(NA)isdefectiveduetoitsEulerianframework.Inthispaper,anewtechniqueisproposedtoupdatesoilmaterialpropertiesbyintroducingthermo-mechanicalcoupledanalysis(TMCA)totheCELmodels.DuringestablishmentoftheCELmodels,theoptimalpenetrationvelocityandminimummeshsizearedeterminedthroughparametricstudies.Reasonabilityandaccuracyarethenverifiedthroughcomparisonofthepreliminaryresultswiththesoilflowconfigurationandpenetrationresistance(Fv)ofacentrifugetest,andtheresultsoftheproposedmethodarecomparedwiththoseoftheremeshingandinterpolationtechniquewithsmallstrain(RITSS)method.ToachieveaCELmodelwithsatisfactoryaccuracy,theNAandTMCAmethodsimplementedintheCELmodelsandtheRITSSmethodarefirstadoptedinweightlesssoil.ComparisonofthefindingswiththoseobtainedinpreviousstudiesshowsthattheTMCAmethodcanupdatematerialpropertiesandpredictFv.TheTMCAmethodisthenappliedtosoilswithself-weightanddifferentshearstrengthprofiles.Resultsshowthattheproposedmethodiscapableofaccuratelymodelingthelargedeformationproblemofspudcanpenetrationinnon-homogeneousclay.

  • 标签: THERMO-MECHANICAL COUPLED analysis NON-HOMOGENEOUS clay SPUDCAN
  • 简介:浮标系统的推广是为浮标系统的操作的最重要的过程之一。在现在的学习,包含表面浮标的一个单个点的绳索浮标系统,有部件的电报片断,锚被使用多身体动力学等等建模方法。运动方程在分离节点描述和充分笛卡儿的坐标被开发。然后数字的方法被用来解决平常的微分方程,当锚从董事会正在扔时,动力学模拟被完成。没有电流并且与在浮标系统的电流的不同节点的轨道和速度被获得。电缆线的每部分的短暂紧张力量在推广的进程被分析。当锚正在摸海床和力量将与不同漂浮配置改变的最大的紧张时,数字结果显示短暂收费载重增加到山峰价值。这个工作对浮标系统计划的设计和推广有用。

  • 标签: 浮标系统 动力学方法 单点系泊 部署 多体 完全笛卡尔坐标
  • 简介:Animpedanceanalyticalmethod(IAM)isdevelopedtostudytheinteractionofplanewaterwavewithaslotted-wallcaissonbreakwater.Thenon-linearboundaryconditionattheslotted-wallisexpressedintermsofflowresistance.Asetofalgebraicexpressionsareobtainedforfreesurfaceelevationinsideandoutsidechamber,andreflectioncoefficient.Thepredictionofthereflectioncoefficientsshowsthattherelativewidthsofthechamberinducingtheminimumreflectioncoefficientforaslotted-wallcaissonbreakwaterareinarangeof0.10~0.20,whicharesmallerthanthat(0.15~0.25)foraperforated-wallcaissonbreakwater.Thereflectioncoefficientsandfreesurfaceelevationobtainedbythepresentmodelarecomparedwiththatoflaboratoryexperimentscarriedoutbypreviousresearchers.

  • 标签: 阻抗分析法 防波堤 沉箱 槽壁 非线性边界条件 反射系数