简介:Large-scaleMIMO(multiple-inputmultiple-output)systemswithnumerouslow-powerantennascanprovidebetterperformanceintermsofspectrumefficiency,powersavingandlinkreliabilitythanconventionalMIMO.Forlarge-scaleMIMO,thereareseveraltechnicalissuesthatneedtobepracticallyaddressed(e.g.,pilotpatterndesignandlow-powertransmissiondesign)andtheoreticallyaddressed(e.g.,capacitybound,channelestimation,andpowerallocationstrategies).Inthispaper,weanalyzethesumrateupperboundoflarge-scaleMIMO,investigateitskeytechnologiesincludingchannelestimation,downlinkprecoding,anduplinkdetection.Wealsopresentsomeperspectivesconcerningnewchannelmodelingapproaches,advanceduserschedulingalgorithms,etc.
简介:Invideoinformationretrieval,keyframeextractionhasbeenrecognizedasoneoftheimportantresearchissues.Althoughmuchprogresshasbeenmade,theexistingapproachesareeithercomputationallyexpensiveorineffectiveincapturingsalientvisualcontent.Inthispaper,wefirstdiscusstheimportanceofkeyframeextractionandthenbrieflyreviewandevaluatetheexistingapproaches.Toovercometheshortcomingeoftheexistingapproaches,weintroduceanewalgorithmforkeyframeextractionbasedonunsupervisedclustring.Meanwhile,weprovideafeedbackchaintoadjustthegranularityoftheextractionresult.Theproposedalgorithmisbothcomputationallysimpleandabletocapturethevisualcontent.Theefficiencyandeffectivenessarevalidatedbylargeamountofreal-worldvideos.
简介:Identity-basedhashproofsystemisabasicandimportantprimitive.Ittographicschemesandprotocolsthataresecureagainstkey-leakageattacks.Inthisupdatableidentity-basedhashproofsystem,inwhichtherelatedmastersecretkeyiswidelyutilizedtoconstructcryp-paper,weintroducetheconceptofandtheidentitysecretkeycanbeupdatedsecurely.Then,weinstantiatethisprimitivebasedonlatticesinthestandardmodel.Moreover,weintroduceanapplicationofthisnewprimitivebygivingagenericconstructionofleakage-resilientpublic-keyencryptionschemeswithanonymity.Thisconstructioncanbeconsideredastheintegrationofthebounded-retrievalmodelandthecontinualleakagemodel.Comparedwiththeexistingleakage-resilientschemes,ourconstructionnotonlyismoreefficientbutalsocanresistmuchmorekeyleakage.
简介:人才高消费及其引发知识性失业的状况表明,我国已出现教育过度现象,应引起我们的足够重视,有必要使用教育过度理论对其进行思考和研究.从教育过度理论的角度,对知识性失业问题作进一步的探讨是有益的.
简介:在传统教学模式下,教师只是在课堂上对学生进行语文教学,学生也只是机械地听取教师向他们传授的语文学科知识,学生在课堂的学习中严重缺乏积极性和主动性,学生很难融入小学语文的教学过程中来,小学语文教学是脱离学生的现实生活的,导致学生缺乏语文学科学习的兴趣,而且不能将自己在课堂上所学到的知识运用于生活中,无法体现语文教学的实际意义。为了提高学生学习语文学科的效率,作为一名小学语文教师,应该将语文学科与学生的生活实际紧密地结合在一起,促使学生在语文学习中更加高效,这样一来,学生可以在平时的生活中对语文学科进行有效学习,激发学生学习语文的积极性,促使学生更加主动地参与到小学语文教学的环境中,提升学生整体的语文素质,进而促使学生全面健康发展,终有利于实现小学语文教学目标的高效完成。