KnowledgeGraphConstructionfromTextAAAI2017

JAY PUJARA,SAMEER SINGH,BHAVANA DALVI

TutorialOverview

Part3:GraphConstruction

Part1:KnowledgeGraphs

Part4:CriticalAnalysis

Part2:KnowledgeExtraction

2

TutorialOutline1. KnowledgeGraphPrimer [Jay]

2. KnowledgeExtractionfromText

a. NLPFundamentals [Sameer]b. InformationExtraction [Bhavana]

CoffeeBreak

3. KnowledgeGraphConstructiona. ProbabilisticModels [Jay]b. EmbeddingTechniques [Sameer]

4. CriticalOverviewandConclusion [Bhavana]

3

WhatisKnowledgeExtraction?

4

John was born in Liverpool, to Julia and Alfred Lennon.Text

JohnLennon

AlfredLennon

JuliaLennon

Liverpoolbirthplace

childOf

childOf

LiteralFacts

NLPFundamentalsEXTRACTINGSTRUCTURESFROMLANGUAGE

WhatisNLP?

NLP

UnstructuredAmbiguousLotsandlotsofit!

Humanscanreadthem,but… veryslowly… can’trememberall… can’tanswerquestions

“Knowledge”

StructuredPrecise,ActionableSpecifictothetask

Canbeusedfordownstreamapplications,suchascreatingKnowledgeGraphs!

6

WhatisNLP?

John was born in Liverpool, to Julia and Alfred Lennon.

NaturalLanguageProcessing

NNP VBD VBD IN NNP TO NNP CC NNP NNP

John was born in Liverpool, to Julia and Alfred Lennon.Person Location Person Person

Lennon..JohnLennon...

Mrs.Lennon....hismother..

hisfatherAlfredhe

thePool

7

WhatisInformationExtraction?

JohnLennon

AlfredLennon

JuliaLennon

Liverpoolbirthplace

childOf

childOf

spouse

InformationExtraction

NNP VBD VBD IN NNP TO NNP CC NNP NNP

John was born in Liverpool, to Julia and Alfred Lennon.Person Location Person Person

Lennon..JohnLennon...

Mrs.Lennon....hismother..

hisfatherAlfredhe

thePool

8

BreakingitDown

John was born in Liverpool, to Julia and Alfred Lennon.NNP VBD VBD IN NNP TO NNP CC NNP NNP

John was born in Liverpool, to Julia and Alfred Lennon.Person Location Person Person

Lennon..JohnLennon...

Mrs.Lennon....hismother..

hisfatherAlfredhe

thePool

Senten

ce DependencyParsing,Partofspeechtagging,Namedentityrecognition…

Documen

t

Coreference Resolution...

JohnLennon

AlfredLennon

JuliaLennon

Liverpoolbirthplace

childOf

childOf

spouse

Inform

ation

Extractio

n

Entityresolution,Entitylinking,Relationextraction…

9

Tokenization&SentenceSplitting

UsesinKGConstruction:• StrictlyconstrainsotherNLPtasks

• PartsofSpeech• DependencyParsing

• DirectlyeffectsKGnodes/edges• Mentionboundaries• Relationswithinsentences

Howitisdone:• Regularexpressions,butnottrivial

• Mr.,Yahoo!,lower-case• Fornon-English,incrediblydifficult!

• Chinese:no“space”character• Non-trivialforsomedomains…

• Whatisa“token”inBioNLP?

“Mr.BobDobolina isthinkin'ofamasterplan. Whydoesn'thequit?”

[Mr.][Bob][Dobolina][is][thinkin’][of][a][master][plan][.][Why][doesn't][he][quit][?]

10

TaggingthePartsofSpeech

John was born in Liverpool, to Julia and Alfred Lennon.NNP VBD VBD IN NNP TO NNP CC NNP NNP

UsesinKGConstruction:• Entitiesappearasnouns• Verbsareveryuseful

• Foridentifyingrelations• Foridentifyingentitytypes

• ImportantfordownstreamNLP• NER,DependencyParsing,…

Howitisdone:• Contextisimportant!

• run,table, bar,…• Labelwholesentencetogether

• “Structuredprediction”• ConditionalRandomFields,..• Now:CNNs,LSTMs,…

11

DetectingNamedEntities

UsesinKGConstruction:• Mentionsdescribesthenodes• Typesareincrediblyimportant!

• Oftenrestrictrelations• Fine-grainedtypesareinformative!

• Brooklyn:city• Sanders:politician,senator

Howitisdone:• Contextisimportant!

• Georgia,Washington,…• JohnDeere,ThomasCook,…• Princeton,Amazon,…

• Labelwholesentencetogether• Structuredpredictionagain

John was born in Liverpool, to Julia and Alfred Lennon.Person Location Person Person

12

NER:EntityTypes

3class: Location,Person,Organization

4class: Location,Person,Organization,Misc

7class: Location,Person,Organization,Money,Percent,Date,Time

FromStanfordCoreNLP (http://nlp.stanford.edu/software/CRF-NER.shtml)

PERSON People,includingfictional.NORP Nationalitiesorreligiousorpoliticalgroups.FACILITY Buildings,airports,highways,bridges,etc.ORG Companies,agencies,institutions,etc.GPE Countries,cities,states.LOC Non-GPElocations,mountainranges,bodiesof

water.PRODUCT Objects,vehicles,foods,etc.(Notservices.)EVENT Namedhurricanes,battles,wars,sportsevents,etc.WORK_OF_ART Titlesofbooks,songs,etc.LANGUAGE Anynamedlanguage.

StanfordCoreNLP

spaCy.io

13

NER:EntityTypes

•Moreonthislater…

FromLing&Weld.AAAI2012(http://aiweb.cs.washington.edu/ai/pubs/ling-aaai12.pdf)

Fine-grainedTypes

14

DependencyParsing

UsesinKGConstruction:• Incrediblyusefulforrelations!

• Whatverbisattached?• Relationtowhichmention?

• Incrediblyusefulforattributes!• Appositives:“X,theCEO,…”

• Pathsareusedassurfacerelations

Howitisdone:• Model:scoretreesusingfeatures

• Lexical:words,POS,…• Structure:distance,…

• Prediction:Searchovertrees• greedy,spanningtree,belief

propagation,dynamicprog,…

Usinghttp://nlp.stanford.edu:8080/corenlp/process 15

DependencyPaths

John was born in Liverpool, to Julia and Alfred Lennon.

John, Liverpool

John, Julia

John, Alfred Lennon

TextPatterns

“wasbornin”

“wasborninLiverpool,to”

“wasborninLiverpool,toJuliaand”

DependencyPaths

“wasbornin”

“wasbornto”

“wasbornto”

nmod:to

nmod:in

case

case

16

Within-documentCoreference

John was born in Liverpool, to Julia and Alfred Lennon.

Mrs.Lennon....hismother..

hisfather

Alfred

hethePool

UsesinKGConstruction:• Morecontextforeachentity!• Manyrelationsoccuronpronouns

• “Heismarriedtoher”• Coref canbeusedfortypes

• Nominals:Thepresident,…• Difficult,sooftenignored

Howitisdone:• Mo`del:scorepairwiselinks

• deppath,similarity,types,…• “representativemention”

• Prediction:Searchoverclusterings• greedy(lefttoright),ILP,

beliefpropagation,MCMC,…

Lennon..

JohnLennon...

He…

17

InformationExtraction

JohnLennon

AlfredLennon

JuliaLennon

Liverpoolbirthplace

childOf

childOf

spouse

InformationExtraction

NNP VBD VBD IN NNP TO NNP CC NNP NNP

John was born in Liverpool, to Julia and Alfred Lennon.Person Location Person Person

Lennon..JohnLennon...

Mrs.Lennon....hismother..

hisfatherAlfredhe

thePool

18

SurfacePatternsCombinetokens,dependencypaths,andentitytypestodefinerules.

Argument1 Argument2,Person Organization

DT CEO of

appos nmod

casedet

BillGates,theCEOofMicrosoft,said…Mr.Jobs,thebrilliantandcharmingCEOofAppleInc.,said…… announcedbySteveJobs,theCEOofApple.… announcedbyBillGates,thedirectorandCEOofMicrosoft.… musedBill,aformerCEOofMicrosoft.andmanyotherpossibleinstantiations…

19

Rule-BasedExtraction

Highprecision:whenitfires,it’scorrectEasytoexplainpredictionsEasytofixmistakes

Useacollectionofrulesasthesystemitself

However…OnlyworkwhentherulesfirePoorrecall:Donotgeneralize!

Argument1 Argument2,Person Organization

DT CEO of

appos nmod

casedet Implies Argument1 Argument2headOf

Source:• Manuallyspecified• LearnedfromDataMultipleRules:• Attachpriorities/precedence• Attachprobabilities(morelater)

Variations

20

SupervisedExtraction

MachineLearning:hopefully,generalizesthelabelsintherightway

UseallofNLPasfeatures:words,POS,NER,dependencies,embeddings

However

Usually,alotoflabeleddata isneeded,whichisexpensive&timeconsuming.Requiresalotoffeatureengineering!

Classifier

P(birthplace)= 0.75

John was born in Liverpool, to Julia and Alfred Lennon.

FeatureEngineering

…NER DepPath Textinb/w embeddingsPOS

21

EntityResolution&Linking

...during the late 60's and early 70's, Kevin Smith worked with several local...

...the term hip-hop is attributed to Lovebug Starski. What does it actually mean...

The filmmaker Kevin Smith returns to the role of Silent Bob...

Nothing could be more irrelevant to Kevin Smith's audacious ''Dogma'' than ticking off...

Like Back in 2008, the Lions drafted Kevin Smith, even though Smith was badly...

... backfield in the wake of Kevin Smith's knee injury, and the addition of Haynesworth...

... The Physiological Basis of Politics,” by Kevin Smith, Douglas Oxley, Matthew Hibbing...

22

EntityNames:TwoMainProblems

DifferentNamesforEntities

InconsistentReferencesMSFT,APPL,GOOG…

Typos/MisspellingsBaarak,Barak,Barrack,…

NickNamesBamBam,Drumpf,…

EntitieswithSameName

PartialReference

Thingsnamedaftereachother

Firstnamesofpeople,Locationinsteadofteamname,Nicknames

Clinton,Washington,Paris,Amazon,Princeton,Kingston,…

SametypeofentitiessharenamesKevinSmith,JohnSmith,Springfield,…

23

EntityLinkingApproach

24

Washington drops 10 points after game with UCLA Bruins.

CandidateGenerationWashingtonDC,GeorgeWashington,Washingtonstate,LakeWashington,WashingtonHuskies,DenzelWashington,UniversityofWashington,WashingtonHighSchool,…

EntityTypesWashingtonDC,GeorgeWashington,Washingtonstate,LakeWashington,WashingtonHuskies,DenzelWashington,UniversityofWashington,WashingtonHighSchool,…

LOC/ORG

CoreferenceWashingtonDC,GeorgeWashington,Washingtonstate,LakeWashington,WashingtonHuskies,DenzelWashington,UniversityofWashington,WashingtonHighSchool,…

UWashington,Huskies

Coherence UCLABruins,USCTrojans

WashingtonDC,GeorgeWashington,Washingtonstate,LakeWashington,WashingtonHuskies,DenzelWashington,UniversityofWashington,WashingtonHighSchool,…

Vinculum,Ling,Singh,Weld,TACL(2015)

InformationExtraction

JohnLennon

AlfredLennon

JuliaLennon

Liverpoolbirthplace

childOf

childOf

spouse

InformationExtraction

NNP VBD VBD IN NNP TO NNP CC NNP NNP

John was born in Liverpool, to Julia and Alfred Lennon.Person Location Person Person

Lennon..JohnLennon...

Mrs.Lennon....hismother..

hisfatherAlfredhe

thePool

25