学科分类
/ 25
500 个结果
  • 简介:RandomMatrixTheory(RMT)isavaluabletoolfordescribingtheasymptoticbehaviorofmultiplesystems,especiallyforlargematrices.Inthispaper,usingasymptoticrandommatrixtheory,anewcooperativeMultiple-InputMultiple-Output(MIMO)schemeforspectrumsensingisproposed,whichshowshowasymptoticfreepropertyofrandommatricesandthepropertyofWishartdistributioncanbeusedtoassistspectrumsensingforCognitiveRadios(CRs).SimulationsoverRayleighfadingandAWGNchannelsdemonstratetheproposedschemehasbetterdetectionperformancecomparedwiththeenergydetectiontechniqueseveninthecaseofasmallsampleofobservations.

  • 标签:
  • 简介:Inrecentyears,theredtideeruptedfrequently,andcausedagreateconomicloss.Atpresent,mostliteraturesemphasizetheacademicresearchonthegrowthmechanismofredtidealga.Inordertofindoutthecharactersofredtideindetailandimprovetheprecisionofforecast,thispapergivessomenewapproachestodealingwiththeredtide.Bytheextremevalues,wedealwiththeredtidefrequencyanalysisandgettheestimationofT-timesredtidelevelU(T),whichistheleveloncetheconsistenceofredtidealgaexceedsontheaverageinaperiodofTtimes.

  • 标签: 赤潮 海洋污染 频率 预报方法
  • 简介:Thesimilaritytheorywassystematicallyintroduced,bycombiningthetheoryandtheanalytichierarchyprocess(AHP),andtakingthedynamicchangesoftwo-stagegreenlandpatchesinShenzhenasanexample,thepatchessimilarityofeachdistrictandeachgreenlandtypewereestimated.Thelocation,shapeandareasofgreenlandunitwereusedasthesimilarityelements.Thenthesimilaritycoefficientscanbedefined.Theoverlappingnumberofgreenlandpatchesindicatedthelocationvariationofgreenland.Theratioofminimumandmaximumshapeindexofgreenlandindicatedtheshapevariationofgreenland.Withthesamemethod,theareasvariationcoefficientwasalsoobtained.Theresultsshowsthatbasedonsimilaritytheoryandmethodtheestimationofgreenlandvariationisfeasible,whichcanprovideeffectivemethodsandaccordanceforthefurtherassessmentofgreenlanddevelopmentinShenzhenSpecialEconomicZone.

  • 标签: SIMILARITY theory green LAND PATCH dynamic
  • 简介:Featureselection(FS)isaprocesstoselectfeatureswhicharemoreinformative.Itisoneoftheimportantstepsinknowledgediscovery.Theproblemisthatnotallfeaturesareimportant.Someofthefeaturesmayberedundant,andothersmaybeirrelevantandnoisy.TheconventionalsupervisedFSmethodsevaluatevariousfeaturesubsetsusinganevaluationfunctionormetrictoselectonlythosefeatureswhicharerelatedtothedecisionclassesofthedataunderconsideration.However,formanydataminingapplications,decisionclasslabelsareoftenunknownorincomplete,thusindicatingthesignificanceofunsupervisedfeatureselection.However,inunsupervisedlearning,decisionclasslabelsarenotprovided.Inthispaper,weproposeanewunsupervisedquickreduct(QR)algorithmusingroughsettheory.ThequalityofthereduceddataismeasuredbytheclassificationperformanceanditisevaluatedusingWEKAclassifiertool.Themethodiscomparedwithexistingsupervisedmethodsandtheresultdemonstratestheefficiencyoftheproposedalgorithm.

  • 标签: 无监督学习 粗糙集理论 约简算法 特征选择 知识发现 数据挖掘
  • 简介:ThispaperexaminestheeffectofgovernmentpoliciesonthefinancingdecisionsoffirmsinChina.Arealoptionsmodelisdevelopedtounderstandhowfiscalandmonetarypoliciesaffectcorporateleverage.Themodelpredictionswillbetestedwithacomprehensivepaneldatasetspanningfrom2002to2011.Thisworkdocumentsrobustevidencethatshowthepositiveassociationofbothtaxandrisk-freeratewithfirmleverage:increaseintaxrateandriskfreeratebyonestandarddeviationresultsintheincreaseincorporateleveragesby0.61to1.06percentand2.54to3.68percent,respectively.Inaddition,theproductionsofthefirmsarenotaffectedbythetaxrateintheshortrun,andthefirmsareoperatingintheiroptimalmarketleverage.Theimpliedtaxrateandriskfreeratearesolvedbyassumingthatthefirmsachievetheiroptimalleverages.Theimpliedtaxratedeclineswiththesize,whereastheoppositegoesforimpliedrisk-freerate.

  • 标签: 企业融资 中国企业 政府政策 决策 模型预测 货币政策
  • 简介:ThispaperpresentsdesigntheoryandmethodoftheintellectualizedCAI.whichincludestheorganizationandexpressionoftheteachingcontentandtheteachingrequirementdeterminationinteachingprocess,anddevelopsahighlyintellectualizedCA1software.LA-CAI,touseforlinerarithmeticteachingprogram.

  • 标签: CAI intellectualization SOFTWARE
  • 简介:Fromthecomparisonofcorrelationtensorinthetheoryofquantumnetwork,theAlexanderrelationmatrixinthetheoryofknotcrystalsandtheidenticalinversionrelationsundertheactionofPaulimatrices,weshowthatthereisaonetoonecorrespondencebetweenfourBellbasesandfourorientedlinksofthelinkage41inknottheory.

  • 标签: 量子力学 量子网络 结理论 有向链
  • 简介:Withthedevelopmentofscienceandtechnology,largequantitiesofneologismsarecreated.Neologismsaretheresultofpeople’sconceptualizationofnewthingsbasedontheirlifeexperiences.Cognitivelinguisticsviewsthatcategorizationoforganismsandconcreteobjectsarebasedontheprototypecategory.Thispapertakes167EnglishNeologismsfromWordspyin2015asthedataforanalysisandfindsthattheseEnglishNeologismsarecharacterizedbyfamilyresemblances,degreeofmembershipincategoryandboundaryfuzzinessfromtheviewofprototypecategorytheory.ThisstudyalsohassomeimplicationsfortheresearchofEnglishlanguageteachingandlearning.

  • 标签:
  • 简介:Byusingthelogarithmicstrain,thefinitedeformationplastictheory,correspondingtotheinfinitesimalplastictheory,isestablishedsuccessively.Theplasticconsistentalgorithmwithfirstorderaccuracyforthefiniteelementmethod(FEM)isdeveloped.Numericalexamplesarepresentedtoillustratethevalidityofthetheoryandeffectivenessofthealgorithm.

  • 标签: FINITE element FINITE deformation elasto-plasticity CONSISTENT
  • 简介:ThispaperstudiesthepowercontrolprobleminfemtocellsystembasedonNashnon-cooperativegametheory.Itdesignsanutilityfunctiontakingfemstations'transmitpowerasvariableandrelatesittotherequirementsofmacrousers'andfemusers'signaltointerferenceplusnoiseratio(SINR).Theutilityalsotakestheimpactoffemstations'locationintoaccountandimprovesthefairnessofnon-cooperativegame.Onthisbasis,thispaperproposesadistributedpowercontrolalgorithmandprovestheexistenceanduniquenessofParetooptimalpoint.Thesimulationresultsshowthatthealgorithmimprovestheconvergencespeedandsystemperformancethroughimprovingusers'SINR.

  • 标签: SC-FDMA 电信 信号处理系统 通信