哈工大深圳-08ML试题+答案

《哈工大深圳-08ML试题+答案》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、1Givethedefinitionsoryourcomprehensionsofthefollowingterms.(12’)1.1TheinductivelearninghypothesisP171.2OverfittingP491.4ConsistentlearnerP1482Givebriefanswerstothefollowingquestions.(15’)2.2Ifthesizeofaversionspaceis,Ingeneralwhatisthesmallestnumberofqueriesmayberequiredbyaconceptlearn

2、erusingoptimalquerystrategytoperfectlylearnthetargetconcept?P272.3Ingenaral,decisiontreesrepresentadisjunctionofconjunctionsofconstrainsontheattributevaluesofinstanse,thenwhatexpressiondoesthefollowingdecisiontreecorrespondsto?OutLookHumidityWindSunnyOvercastRainYesHighNormalYesNoStron

3、gYesWeakNo3Givetheexplainationtoinductivebias,andlistinductivebiasofCANDIDATE-ELIMINATIONalgorithm,decisiontreelearning(ID3),BACKPROPAGATIONalgorithm.(10’)4Howtosolveoverfittingindecisiontreeandneuralnetwork?(10’)Solution:lDecisiontree:u及早停止树增长(stopgrowingearlier)u后修剪法(post-pruning)lNe

4、uralNetworku权值衰减(weightdecay)u验证数据集(validationset)5ProvethattheLMSweightupdateruleperformsagradientdescenttominimizethesquarederror.Inparticular,definethesquarederrorEasinthetext.NowcalculatethederivativeofEwithrespecttotheweight,assumingthatisalinearfunctionasdefinedinthetext.Gradient

5、descentisachievedbyupdatingeachweightinproportionto.Therefore,youmustshowthattheLMStrainingrulealtersweightsinthisproportionforeachtrainingexampleitencounters.()(8’)Solution：AsVtrain(b)ß(Successor(b))wecangetE==AsmentionedinLMS:WecangetTherefore,gradientdescentisachievementbyupdatingea

6、chweightinproportionto;LMSrulesaltersweightsinthisproportionforeachtrainingexampleitencounters.6Trueorfalse:ifdecisiontreeD2isanelaborationoftreeD1,thenD1ismore-general-thanD2.AssumeD1andD2aredecisiontreesrepresentingarbitrarybooleanfuncions,andthatD2isanelaborationofD1ifID3couldextend

7、D1toD2.Iftruegiveaproof;iffalse,acounterexample.(Definition:Letandbeboolean-valuedfunctionsdefinedover.thenismore_general_than_or_equal_to(written)Ifandonlyifthen)(10’)Thehypothesisisfalse.OnecounterexampleisAXORBwhileifA!=B,trainingexamplesareallpositive,whileifA==B,trainingexamples