台大-李宏毅-B站机器学习视频-课件神经网络与深度学习Structured Linear

StructuredLinearModel,Hung-yiLee,StructuredLinearModel,inaspecificform,StructuredLinearModel:Problem1,Evaluation:WhatdoesF(x,y)looklike?,Learningfromdata,Characteristics,Evaluation:WhatdoesF(x,y)looklike?Example:ObjectDetection,StructuredLinearModel:Problem1,percentageofcolorredinboxy,=,percentageofcolorredoutofboxy,areaofboxy,numberofspecificpatternsinboxy,percentageofcolorgreeninboxy,percentageofcolorblueinboxy,StructuredLinearModel:Problem1,Evaluation:WhatdoesF(x,y)looklike?Example:Summarization,(Shortparagraph),(alongdocument),Lengthofy,Whetherthesentencecontainingtheword“important”isiny,Whetherthesentencecontainingtheword“definition”isiny,Howsuccinctisy?,Howrepresentativeofy?,StructuredLinearModel:Problem1,Evaluation:WhatdoesF(x,y)looklike?Example:Retrieval,(Inputkeyword),(SearchResult),Howmuchdifferentinformationdoesycover?(Diversity),Thedegreeofrelevancewithrespecttoxforthetop1webpagesiny.,Isthetop1webpagemorerelevantthanthetop2webpage?,StructuredLinearModel:Problem2,Inference:Howtosolvethe“argmax”problem,Assumewehavesolvedthisquestion.,StructuredLinearModel:Problem3,Training:Giventrainingdata,howtolearnF(x,y)F(x,y)=w(x,y),sowhatwehavetolearnisw,Trainingdata:,Weshouldfindwsuchthat,(Allincorrectlabelforr-thexample),(Alltrainingexamples),StructuredLinearModel:Problem3,1,1,2,2,StructuredLinearModel:Problem3,1,1,2,2,StructuredLinearModel:Problem3,1,1,2,2,SolutionofProblem3,Difficult?,Notasdifficultasexpected,Algorithm,Input:trainingdatasetOutput:weightvectorwAlgorithm:Initializew=0doForeachpairoftrainingexampleFindthelabelmaximizing,If,updatewuntilwisnotupdated,(question2),Wearedone!,Willitterminate?,Algorithm-Example,1,1,2,2,Algorithm-Example,Initializew=0,pick,Becausew=0atthistime,1,always0,Randompickonepointas,If,updatew,Algorithm-Example,pick,If,updatew,Algorithm-Example,pickagain,donotupdatew,pickagain,donotupdatew,Sowearedone,Assumption:Separable,Thereexistsaweightvector,(Allincorrectlabelforanexample),(Alltrainingexamples),(Thetargetexists),Assumption:Separable,ProofofTermination,wisupdatedonceitseesamistake,(therelationofwkandwk-1),Analysis,(largerandlarger?),(Separable),ProofofTermination,Analysis,(largerandlarger?),(sowhat),wisupdatedonceitseesamistake,(therelationofwkandwk-1),=0,ProofofTermination,?,(mistake),AssumethedistancebetweenanytwofeaturevectorissmallerthanR,ProofofTermination,ProofofTermination,Margin:Isiteasytoseparableredpointsfromtheblueones,Normalization,Allf