KnowledgeGraph
Construction
fromText
AAAI2017
J AY P UJARA ,S AMEER S INGH ,B HAVANA D ALVI
TutorialOverview
Part1:KnowledgeGraphs
Part2:
Knowledge
Extraction
Part3:
Graph
Construction
Part4:CriticalAnalysis
2
TutorialOutline
1. KnowledgeGraphPrimer
[Jay]
2. KnowledgeExtractionfromText
a.
b.
NLPFundamentals
InformationExtraction
[Sameer]
[Bhavana]
CoffeeBreak
3. KnowledgeGraphConstruction
a.
b.
ProbabilisticModels
EmbeddingTechniques
[Jay]
[Sameer]
4. CriticalOverviewandConclusion [Bhavana]
3
WhatisKnowledgeExtraction?
Text
John was born in Liverpool, to Julia and Alfred Lennon.
LiteralFacts
Alfred
Lennon
childOf
Liverpool
birthplace
John
Lennon
childOf
Julia
Lennon
4
NLP
Fundamentals
EXTRACTINGSTRUCTURESFROMLANGUAGE
WhatisNLP?
NLP
Unstructured
Ambiguous
Lotsandlotsofit!
Humanscanreadthem,but
… veryslowly
… can’trememberall
… can’tanswerquestions
“Knowledge”
Structured
Precise,Actionable
Specifictothetask
Canbeusedfordownstream
applications,suchascreating
KnowledgeGraphs!
6
WhatisNLP?
John was born in Liverpool, to Julia and Alfred Lennon.
NaturalLanguage
Processing
Lennon..
JohnLennon...
thePool
Person
Location
Mrs.Lennon..
..hismother..
Person
hisfather
he Alfred
Person
John was born in Liverpool, to Julia and Alfred Lennon.
NNP VBD VBD IN
NNP
TO NNP CC
NNP
NNP
7
WhatisInformationExtraction?
Lennon..
JohnLennon...
thePool
Person
Location
Mrs.Lennon..
..hismother..
Person
hisfather
he Alfred
Person
John was born in Liverpool, to Julia and Alfred Lennon.
NNP VBD VBD IN
NNP
TO NNP CC
NNP
NNP
InformationExtraction
Alfred
Lennon
childOf
Liverpool
birthplace
John
Lennon
spouse
childOf
Julia
Lennon
8
Document
Entityresolution,
Entitylinking,
Relationextraction…
Coreference Resolution...
Sentence
Information
Extraction
BreakingitDown
DependencyParsing,
Partofspeechtagging,
Namedentityrecognition…
Alfred
Lennon
childOf
Liverpool
birthplace
spouse
John
Lennon
childOf
Lennon..
JohnLennon...
Person
thePool
Location
Julia
Lennon
Mrs.Lennon..
..hismother..
Person
hisfather
he Alfred
Person
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.
9
Tokenization&SentenceSplitting
“Mr.BobDobolina isthinkin'ofamasterplan. Whydoesn'thequit?”
[Mr.][Bob][Dobolina][is][thinkin’][of][a][master][plan][.]
[Why][doesn't][he][quit][?]
Howitisdone:
• Regularexpressions,butnottrivial
• Mr.,Yahoo!,lower-case
• Fornon-English,incrediblydifficult!
• Chinese:no“space”character
• Non-trivialforsomedomains…
• Whatisa“token”inBioNLP?
UsesinKGConstruction:
• StrictlyconstrainsotherNLPtasks
• PartsofSpeech
• DependencyParsing
• DirectlyeffectsKGnodes/edges
• Mentionboundaries
• Relationswithinsentences
10
TaggingthePartsofSpeech
NNP VBD VBD IN
NNP
TO NNP
CC
NNP
NNP
John was born in Liverpool, to Julia and Alfred Lennon.
Howitisdone:
• Contextisimportant!
• run,table, bar,…
• Labelwholesentencetogether
• “Structuredprediction”
• ConditionalRandomFields,..
• Now:CNNs,LSTMs,…
UsesinKGConstruction:
• Entitiesappearasnouns
• Verbsareveryuseful
• Foridentifyingrelations
• Foridentifyingentitytypes
• ImportantfordownstreamNLP
• NER,DependencyParsing,…
11
DetectingNamedEntities
Person
Location
Person
Person
John was born in Liverpool, to Julia and Alfred Lennon.
Howitisdone:
• Contextisimportant!
• Georgia,Washington,…
• JohnDeere,ThomasCook,…
• Princeton,Amazon,…
• Labelwholesentencetogether
• Structuredpredictionagain
UsesinKGConstruction:
• Mentionsdescribesthenodes
• Typesareincrediblyimportant!
• Oftenrestrictrelations
• Fine-grainedtypesareinformative!
• Brooklyn:city
• Sanders:politician,senator
12
NER:EntityTypes
StanfordCoreNLP
spaCy.io
3class:
Location,Person,Organization
4class:
Location,Person,Organization,Misc
7class:
Location,Person,Organization,Money,Percent,Date,Time
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.
FromStanfordCoreNLP (http://nlp.stanford.edu/software/CRF-NER.shtml)
13
NER:EntityTypes
Fine-grainedTypes
• Moreonthislater…
FromLing&Weld.AAAI2012(http://aiweb.cs.washington.edu/ai/pubs/ling-aaai12.pdf)
14
DependencyParsing
Howitisdone:
• Model:scoretreesusingfeatures
• Lexical:words,POS,…
• Structure:distance,…
• Prediction:Searchovertrees
• greedy,spanningtree,belief
propagation,dynamicprog,…
Usinghttp://nlp.stanford.edu:8080/corenlp/process
UsesinKGConstruction:
• Incrediblyusefulforrelations!
• Whatverbisattached?
• Relationtowhichmention?
• Incrediblyusefulforattributes!
• Appositives:“X,theCEO,…”
• Pathsareusedassurfacerelations
15
DependencyPaths
nmod:to
nmod:in
John was born in Liverpool, to Julia and Alfred Lennon.
case
case
TextPatterns
John, Liverpool
John, Julia
John, Alfred Lennon
“wasbornin”
“wasborninLiverpool,to”
“wasborninLiverpool,toJuliaand”
DependencyPaths
“wasbornin”
“wasbornto”
“wasbornto”
16
Within-documentCoreference
Mrs.Lennon..
He…
Lennon..
thePool
..hismother..
JohnLennon...
Alfred
hisfather
he
John was born in Liverpool, to Julia and Alfred Lennon.
Howitisdone:
• Mo`del:scorepairwiselinks
• deppath,similarity,types,…
• “representativemention”
• Prediction:Searchoverclusterings
• greedy(lefttoright),ILP,
beliefpropagation,MCMC,…
UsesinKGConstruction:
• Morecontextforeachentity!
• Manyrelationsoccuronpronouns
• “Heismarriedtoher”
• Coref canbeusedfortypes
• Nominals:Thepresident,…
• Difficult,sooftenignored
17
InformationExtraction
Lennon..
JohnLennon...
thePool
Person
Location
Mrs.Lennon..
..hismother..
Person
hisfather
he Alfred
Person
John was born in Liverpool, to Julia and Alfred Lennon.
NNP VBD VBD IN
NNP
TO NNP CC
NNP
NNP
InformationExtraction
Alfred
Lennon
childOf
Liverpool
birthplace
John
Lennon
spouse
childOf
Julia
Lennon
18
SurfacePatterns
Combinetokens,dependencypaths,andentitytypestodefinerules.
appos
nmod
case
det
Argument1
Person
, DT
CEO of
Argument2
Organization
BillGates,theCEOofMicrosoft,said…
Mr.Jobs,thebrilliantandcharmingCEOofAppleInc.,said…
… announcedbySteveJobs,theCEOofApple.
… announcedbyBillGates,thedirectorandCEOofMicrosoft.
… musedBill,aformerCEOofMicrosoft.
andmanyotherpossibleinstantiations…
19
Rule-BasedExtraction
appos
nmod
case
det
Argument1
Person
, DT
CEO of
Implies
Argument1
headOf
Argument2
Argument2
Organization
Variations
Source:
• Manuallyspecified
• LearnedfromData
MultipleRules:
• Attachpriorities/precedence
• Attachprobabilities(morelater)
Useacollectionofrulesasthesystemitself
Highprecision:whenitfires,it’scorrect
Easytoexplainpredictions
Easytofixmistakes
However…
Onlyworkwhentherulesfire
Poorrecall:Donotgeneralize!
20
SupervisedExtraction
MachineLearning:hopefully,
generalizesthelabelsintherightway
UseallofNLPasfeatures:words,
POS,NER,dependencies,embeddings
P(birthplace)= 0.75
Classifier
POS NER DepPath Textinb/w embeddings
However
Usually,alotoflabeleddata isneeded,
whichisexpensive&timeconsuming.
Requiresalotoffeatureengineering!
…
FeatureEngineering
John was born in Liverpool, to Julia and Alfred Lennon.
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...
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 filmmaker Kevin Smith returns to the role of Silent Bob...
Nothing could be more irrelevant to Kevin Smith's audacious ''Dogma'' than ticking off...
... The Physiological Basis of Politics,” by Kevin Smith, Douglas Oxley, Matthew Hibbing...
22
EntityNames:TwoMainProblems
EntitieswithSameName
Sametypeofentitiessharenames
KevinSmith,JohnSmith,
Springfield,…
Thingsnamedaftereachother
Clinton,Washington,Paris,
Amazon,Princeton,Kingston,…
PartialReference
Firstnamesofpeople,Location
insteadofteamname,Nicknames
DifferentNamesforEntities
NickNames
BamBam,Drumpf,…
Typos/Misspellings
Baarak,Barak,Barrack,…
InconsistentReferences
MSFT,APPL,GOOG…
23
EntityLinkingApproach
Washington drops 10 points after game with UCLA Bruins.
CandidateGeneration
WashingtonDC,GeorgeWashington,Washingtonstate,
LakeWashington,WashingtonHuskies,DenzelWashington,
UniversityofWashington,WashingtonHighSchool,…
WashingtonDC,GeorgeWashington,Washingtonstate,
LakeWashington,WashingtonHuskies,DenzelWashington,
UniversityofWashington,WashingtonHighSchool,…
EntityTypes
LOC/ORG
Coreference
WashingtonDC,GeorgeWashington,Washingtonstate,
UWashington, LakeWashington,WashingtonHuskies,DenzelWashington,
Huskies
UniversityofWashington,WashingtonHighSchool,…
Coherence
UCLABruins,
USCTrojans
Vinculum,Ling,Singh,Weld,TACL(2015)
WashingtonDC,GeorgeWashington,Washingtonstate,
LakeWashington,WashingtonHuskies,DenzelWashington,
UniversityofWashington,WashingtonHighSchool,…
24
InformationExtraction
Lennon..
JohnLennon...
thePool
Person
Location
Mrs.Lennon..
..hismother..
Person
hisfather
he Alfred
Person
John was born in Liverpool, to Julia and Alfred Lennon.
NNP VBD VBD IN
NNP
TO NNP CC
NNP
NNP
InformationExtraction
Alfred
Lennon
childOf
Liverpool
birthplace
John
Lennon
spouse
childOf
Julia
Lennon
25