Semantic Parsing - Columbia Universitykathy/NLP/2017/ClassSlides/Class14... · 2017. 10. 24. ·...

SemanticParsing

Announcements• PlantoreleasemidtermgradesbyThursday• Onedaybehindonsyllabus.Willlikelydropimagecap:oning.

Whatissemanticparsing?• Mappingtoameaningrepresenta:on• Seman:crepresenta:onwithdesiderata•  Seman:croles• Composi:onality•  Truthpreserving

• Applica:onrepresenta:on

TwoExamples• ParsingintoAbstractMeaningRepresenta:on(AMR)• LanguagetoCode:learningparsersforif-this-then-thatrecipes•  Simplerulesthatallowuserstocontrolaspectsoftheirdigitallivesincludingsmartphones•  LargeonlinenaturallyoccurringrepositoryofNLdescrip:onsandassociatedcode

TwoExamples• ParsingintoAbstractMeaningRepresenta2on• LanguagetoCode:learningparsersforif-this-then-thatrecipes•  Simplerulesthatallowuserstocontrolaspectsoftheirdigitallivesincludingsmartphones•  LargeonlinenaturallyoccurringrepositoryofNLdescrip:onsandassociatedcode

AMRcharacteristics• Rooted,labeledgraphs• Abstractawayfromsyntac:cdifferences• Hedescribedherasagenius• Hisdescrip:onofher:genius•  Shewasageniusaccordingtohisdescrip:on• UsePropbankframesets•  “bondinvestor”:invest-01• HeavilybiasedtowardsEnglish

• Variables(ornodes)foren::es,events,proper:es,states• Leafnodesarelabeledwithconcepts:•  (b/boy)aninstanceoftheconceptboy

• Rela:onslinken::es•  (d/die-01:loca:on(p/park)):therewasadeathinthepark

• AMRconcepts•  Englishwords(e.g.,boy),Propbankframesets(e.g.,want-01)orspecialkeywords(en:ty-types,quan::esorconjunc:ons)

AMRrelations•  ~100rela:ons•  Framearguments•  Arg0,arg1,arg2,arg3,arg4,arg5(Propbank)

•  Generalseman:crela:ons•  :Accompanier,:age,:beneficiary,:cause,:compared-to,:concession,:condi:on,:consistof,:degree,:des:na:on,:direc:on,:domain,:dura:on,:employed-by,:example,:extent,:frequency,:instrument,:li,:loca:on,:manner,:medium,:mod,:mode,:name,:part,:path,:polarity,:poss,:purpose,:source,:subevent,:subset,::me,:topic,:value.

•  Rela:onsforquan:ty•  :quant,:unit,:scale

•  Rela:onsfordateen:ty•  :day,:month,:year,:weekday,::me,::mezone,:quarter,:dayperiod,:season,:year2,:decade,:century,:calendar,:era.

•  Rela:onsforlists•  :op1,:op2,….:op10

•  Plusinverses(e.g.,:arg0-of,:loca:on-of)

Framesets• ExamplesofusingFramesetstoextractawayfromEnglishsyntax•  (d/describe-01•  :arg0(m/man)•  :arg1(m2/mission)•  :arg2(d/disaster))

•  :arg0thedescriber,:arg1thethingdescribed,:arg2whatitisdescribing• Themandescribedthemissionasadisaster.Asthemandescribedit,themissionwasadisaster

Generalsemanticrelations• Non-corerela:ons• (s:hum-02•  :arg0(s2/soldier)•  :beneficiary(g/girl)•  ::me(w/walk-01

• :arg0g• :des:na:on(t/town)))

• Thesoldierhummedtothegirlasshewalkedtotown.

Co-reference• AMRabstractsawayfromsurfaceformsforco-referencesuchaspronouns,zero-pronouns,reflexive,controlstructure.Instead,variablesarere-used.• See“g”inpreviousexample.

Inverserelations• Inordertoobtainrootedstructures• (s/sing-01•  :arg0(b/boy

:source(c/college))

• Theboyfromthecollegesang.

• (b/boy•  :arg0-of(s/sing-01):source(c/college))thecollegeboywhosang

ModalsandNegation• Nega:onisrepresentedwith:polarityandmodalityisrepresentedwithconcepts• (g/go-01

:arg0(b/boy):polarity-)

Theboydidnotgo.

• (p/possible:domain(g/go-01 :arg0(b/boy)):polarity-))

Theboycannotgo.It’snotpossiblefortheboytogo.

• (p/obligate-01:arg0(g/go-01 :arg0(b/boy)):polarity-)

• Theboydoesn’thavetogo.• Theboyisnotobligatedtogo.

Questions• Amr-unknowntoindicatewh-ques:ons• (f/find-01

:arg0(g/girl):arg1(a/amr-unknown))

Whatdidthegirlfind?

• (f/find-01):arg0(g/girl):arg1(b/boy):loca:on(a/amr-unknown))

Wheredidthegirlfindtheboy?

• (f/find-01arg0(g/girl)arg1(t/toy :poss(a/amr-unknown))

Sentence??

Verbs• CorrespondtoPropbankframesets(l/look-05

arg0:(b/boy)arg1:(a/answer)

Theboylookeduptheanswer.Theboylookedtheanswerup.

Nouns• PropBankverbframesetsrepresentmanynounsaswell(d/destroy-01

arg0:(b/boy)arg1:(r/room)

thedestruc:onoftheroombytheboytheboy’sdestruc:onoftheroomtheboydestroyedtheroom

• Nominaliza:onisarole(s/see-01)

arg0:(j/judge)arg1:(e/explode-01))

Thejudgesawtheexplosion

• Howabout?(r/read-01

:arg0(j/judge):arg1(t/thing :arg1-of(p/propose-01))

Sentence?

Adjectives• Canalsouseframesets(s/spy

:arg0-of(a/afract-01))theafrac:vespy

• (s/spy:arg0-of(a/afract-01 :arg1(w/woman)))

NP?

Compositionality•  Themeaningofthewholeisequaltothesumofthemeaningofitsparts

•  HowisAMRcomposi:onal?(d/describe-01•  :arg0(m/man):arg1(m2/mission):arg2(d/disaster))

•  (s/spy:arg0-of(a/afract-01))

•  WhatistheAMRfortheafrac:vespydescribedthemissionasadisaster?

AMRdata• Availabledownloads:hfps://amr.isi.edu/download.html•  LiflePrinceavailabletoall•  EnglishandChinese

•  Biomedicaldata•  Generic,wide-rangingcontent:LDC

• ReferencesonAMRdata•  Abstractmeaningrepresenta:onforsembanking:hfps://amr.isi.edu/a.pdf•  GuidelinesforAMRannota:on:amr.isi.edu/language.html

AMRparsing• Manyapproaches•  E.g.,CCG,intologicalform,graphparsing,syntax-basedmachinetransla:on,hyperedgereplacementgrammars

• SemEval2016:Track8onAMRparsinghfp://alt.qcri.org/semeval2016/task8/• Today:AParserforAbstractMeaningRepresenta:onUsingLearningtoSearch

LearningtoSearch(L2S)• Familyofapproachesthatsolvesstructuredpredic:onproblems•  Decomposestheproduc:onofthestructuredoutputintermsofexplicitsearchspace•  Learnshypothesesthatcontrolapolicythattakesac:onsinthesearchspace

• AMRisastructuredseman:crepresenta:on

• Modellearningofconceptsandrela:onsinaunifiedsejng.

AMRparsingtaskdecomposed• Predic:ngconcepts• Predic:ngtheroot• Predic:ngrela:onsbetweenpredicatedconcepts

Searchspace• States={x1,x2,....,xn,y1,y2,….,yi-1}wheretheinput{x1,x2,....,xn}arethenwordsofthesentence• Conceptpredic:on:labelsy1,y2,….,yi-1aretheconceptspredicteduptoi-1.•  Nextac:on:yiistheconceptforwordxifromak-bestlistofconcepts

• Rela:onpredic:on:labelsarerela:onsforpredictedpairsofconcepts• Rootpredic:on:mul:-taskclassifierselectsrootconceptfromallpredictedconcepts

Example

Selectingk-bestlists• Conceptcandidates•  Thesetofallconceptsassignedtosiintheen:retrainingdata•  Ifsiunseen->lemma:zedspan,Propbankframes,andnull

• Rela:oncandidates(fromcitocj)•  Unionof•  Pairwisei,j:Alldirectedrela:onsfromcitocjwhentheyoccurredinthesameAMR

•  Outgoingi:Alloutgoingrela:onsfromci•  Incomingj:Allincomingrela:onsintocj

• Whenunseenintrainingdata,allrela:onsinthetrainingdata.

Whatdoesthislooklike?

Pre-processingfortraining• Wheredospanscomefrom?•  JAMRalignertoalignsentenceswithAMRconceptsandrela:onsintrainingdata•  Singlewordtosingleconcept•  Spanofwordstographfragment:“StoriesfromNature”alignedtographrootedat“name”•  Nameden::es•  Mul:wordexpressions

• Wordalignedtonull•  Func:onwords(e.g.,“to”,“a”,“the”)

Singleconceptormultiple?• BarackObama• Atthedropofahat(e.g.,Iwoulddoanythingforyouatthedropofahat).• ThePresidentoftheUnitedStates

AlignmentDetails• Forcedalignments•  Someconceptsarenotalignedtowords•  Forcealignmentsbasedoncount(unalignedconceptalignedtounalignedwords)acrosstrainingcorpus

• Test:me•  Eachwordasinglespanexcept•  Nameden::es•  Dateand:memul:-wordexpressionsusingregularexpressions

Learning• Ateachstate,learnmul:pleclassifiers•  Oneconcept(rela:on)againstallothers

• Predicttheconcept,rela:on,rootsequencefortheen:resentence• UseHammingdistancetocomputetheloss• Adjustpredic:onbasedonloss->jointlearning

FeaturesforLearningConcepts• Wordsinsiandcontext•  POSofwordsinsiandcontext•  Nameden:tytagsforwordsinsi•  Binaryfeatureindica:ngwhetherwordsinsiarestopwords•  Alldependencyedgesemana:ngfromwordsinsi•  Binaryfeatureindica:ngwhethercistheconceptmostfrequentlyalignedwithsi•  Predictedconceptsforthetwopreviousspans•  Conceptlabelanditsconjunc:onwithallpreviousfeatures•  IfthelabelisaFramesetfeature,thentheframeanditssense

Whatdoesthislooklike?

FeaturesforLearningRelations• Givencicjandr• Thetwoconcepts(cicj)andtheirconjunc:on• Wordsinthecorrespondingspansandtheirconjunc:ons• POStagsofwordsinspansandtheirconjunc:ons• Alldependencyedgeswithtailinwiandheadinwj• BinaryfeaturewhichistrueiffI<j• Rela:onlabelanditsconjunc:onwithallotherlabels

FeaturesforLearningRoot• Conceptlabel.IftheconceptisaFrameset,thentheframeanditssense• Wordsinthespancorrespondingtoconcept• POStagsofwordsinthespan• Binaryfeatureindica:ngwhetheroneofthewordsinthespanistherootofthedependencytree

SomeOddsandEnds• Connec:vity:•  Foreachdisconnectedcomponent,finditsroot•  Thenconnectroottorootofsentence

• Cycles• Nospecificconstraintsagainstcyclesinlearning•  Inprac:ce,only5%ofpredictedAMRgraphshavecycles

Results• Useatool(Smatch)tocomparepredictedAMRwithgoldAMR• F1=.46• P=.51• R=.43• Meanofallsystemsinsharedtask:F1=.55,standarddevia:on.06

TwoExamples• ParsingintoAbstractMeaningRepresenta:on(AMR)• LanguagetoCode:learningparsersforif-this-then-thatrecipes•  Simplerulesthatallowuserstocontrolaspectsoftheirdigitallivesincludingsmartphones•  LargeonlinenaturallyoccurringrepositoryofNLdescrip:onsandassociatedcode

TaskerandIFFT• Simpleprogramswithtriggersandac:ons• PhillipsHuelightbulbstoflashredandbluewhentheCubshitahomerun.Homeautoma:onsensorsandcontrollers• Mo:ondetectors•  Thermostats•  Loca:onsensors•  Garagedooropeners

• Usersdescribetherecipesinnaturallanguageandpublishthem

Goal• Tobuildseman:cparsersthatmapfromNLdescrip:ontotheprogramautoma:cally• Collected114,408recipe-NLpairsfromthehfp://irf.comwebsite

ExampleRecipes• TurnonmylightswhenIarrivehome• Textmeifthedooropnes• Addreceiptemailstoaspreadsheet• RemindmetodrinkwaterifI’vebeenatabarformorethan2hours.

MTapproach• Createdacontextfreegrammarforprograms• GrammarforNLrecipes• Learntomapfromonetotheother• Useseparateclassifiersforeachpossibleac:on

• Isitbe7ertoparseintoAMRordirectlyintothecommandlanguage?• WhatareprosforusingAMR?• WhatareconsforusingAMR?