Graph Representation Learning with Hierarchical Structure ... · Experiment p Facebook social...
Transcript of Graph Representation Learning with Hierarchical Structure ... · Experiment p Facebook social...
GraphRepresentationLearningwithHierarchicalStructureandDomainAdaptation
Speaker:LunDuAffiliation:MicrosoftResearchAsia
2019/10/11 GraphRepresentationLearning 1
MainContents
q Background
q Graphembeddingwithhierarchicalcommunitystructure
q Domainadaptivegraphembedding
q Futureworks
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Background
q GraphEmbeddingtriestomapgraphverticesintoalow-dimensionalvectorspaceundertheconditionofpreservingdifferenttypesofgraphproperties.
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p Node classification
p Link Predictionp Network Visualization
p Community detection
p …...
Background
q Unsupervisedvs.Supervised§ DeepWalk,LINE, node2vec,etc.
§ GCN,GraphSAGE,etc.
q Euclideanvs.Non-Euclidean§ Hyperbolicspace(Tag2Vec,WWW’19)
q Vectorvs.Distribution§ Usingvariancetomodeluncertaintyofsemantic
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MainContents
q Background
q Graphembeddingwithhierarchicalcommunitystructure
q Domainadaptivegraphembedding
q Futureworks
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Outline
q Conceptually,complexnetworkshavehierarchicalcommunity inrealworld.§ E.g.socialnetworks,airtransportationnetworks,andmetabolicnetworks,
etc.
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Outline
q HierarchicalInfocanbeobservedtoacertainextentinonlinenetworks.
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Explicit hierarchy with attributes Implicit hierarchy with tags
#
#University
#Major
#EnrollmentYear
TwitterNetworkFacebook Network
Outline
q Goal:§ Encodingtherichhierarchicalstructuralinformation
qMainChallenges:§ Howtorepresentnodesortags?
§ Howtolearntherepresentationseffectivelyandefficiently?
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GalaxyNetworkEmbedding:AHierarchicalCommunityStructurePreserving
Approach
LunDu,Zhicong Lu,YunWang,GuojieSon𝑔∱ ,YimingWang,WeiChen.GalaxyNetworkEmbedding:AHierarchicalCommunityStructurePreservingApproach.InProceedingsofIJCAI,2018.
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HowtoRepresent?
q Inspiredbygalaxystructureq Embeddingnodesandcommunitiessimultaneously
§ Easytoanalyzethenetworkatdifferentscales.
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(The representations of nodes in tree)
Embedding
HowtoLearn?
q Formulatethehierarchicalcommunitypreservingnetworkembedding§ Oneisthelocalinformation,i.e.pairwisenodessimilarityinthesame
community.
§ Theotheristhehierarchicalstructureproperty,i.e.horizontalrelationshipandverticalrelationship.
q Implementandoptimizeefficientlytheembeddingmethod.
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HierarchicalPreservingNetworkEmbedding
q PairwiseProximityPreservation
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HierarchicalPreservingNetworkEmbedding
q HierarchicalStructurePreservation§ Horizontalrelationship:
§ Verticalrelationship:
𝒄𝒗𝒍𝒄𝒖𝒍 𝒄𝒘𝒍𝒄(𝒍)𝟏
𝒄𝒋𝒍
𝒄𝒌𝒍-𝟏
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GalaxyNetworkEmbedding
q Objective
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Proof
q PairwiseProximityPreservation
q HierarchicalStructurePreservation
§ Horizontal relationship:
§ Vertical relationship:
HierarchicalPreservingNetworkEmbedding
GalaxyNetworkEmbedding
?=>
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Proof
Lemma1
ThecommunityrepresentationslearnedfromrecursivelyoptimizingtheobjectiveEq.(5)with
thestrategyEq.(6)preservetheconstraintsEq.(3)andEq.(4).
⟹Vertical relationship:
Horizontal relationship:
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Experiment
p Facebook social network datasets:
p Amherst Collegep Hamilton Universityp Georgetown University
p Hierarchical random graphs (HRG):
p syn_with_125nodesp syn_with_1800nodesp syn_with_2560nodesp syn_with_3750nodes
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Dataset Baselines
p Spectral Clustering [Tang and Liu, 2011]
p DeepWalk [Perozzi et al, 2014]
p Node2vec [Grover and Leskovec, 2016]
p LINE [Tang et al., 2017]
p GraRep [Cao et al., 2015]
p MNMF [Wang et al., 2017]
Experiment
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Hierarchical Community Detection
Experiment
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Network Visualization
Experiment
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Vertex Classification
HierarchicalCommunityStructurePreservingNetworkEmbedding:ASubspaceApproach
𝐋𝐮𝐧𝐃𝐮∗,𝑄𝑖𝑛𝑔𝑞𝑖𝑛𝑔𝐿𝑜𝑛𝑔∗,Y𝑖𝑚𝑖𝑛𝑔𝑊𝑎𝑛𝑔∗,𝐺𝑢𝑜𝑗𝑖𝑒𝑆𝑜𝑛𝑔∱ ,𝑌𝑖𝐿𝑢𝑛𝑗𝑖𝑛,𝑊𝑒𝑖𝐿𝑖𝑛.HierarchicalCommunityStructurePreservingNetworkEmbedding:ASubspaceApproach.AcceptedbyCIKM,2019.
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DrawbacksofGNE
q Failedwhenembeddingdeepercommunities§ Radiishrinkexponentially
§ Datasparsityinadeepercommunity
q Probablyovervaluedhierarchicalinformation§ Verticesacrosscommunityareexponentially
distantthanthosewithinthesamecommunity.
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HowtoRepresent?
q Subspace§ Naturalhierarchicalstructure
§ Deepercommunitycorrespondingtolowerdimensionalsubspace
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HowtoLearn?
q Formulatingtheproblemintoanoptimizationproblemwithsubspaceconstraints§ Modelingcommunityaffiliationbysubspace
§ Reducingtherepresentationdimbyconstrainingtherankofbasevectors
q Designingefficientlearningalgorithm§ Fromglobaltolayer-wiseoptimization
§ Fromdiscretetodifferentiableoptimization
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HierarchicalStructurePreserved
q PreservationofStructurewithinIndividualCommunities
q PreservationofStructureamongCommunities
q LowRankConstraints
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ℒJ = K log𝜎(||𝑢RS − 𝑢U
S ||) + 𝑘 ⋅ 𝔼[\~ \̂[log𝜎(−||𝑢`S − 𝑢U
S ||)]U ,R ∈c
Where,𝑢U(d) = 𝑆efg 𝑢U
(d-J) for𝑙 = 1…𝐿, 𝑣U ∈ 𝑉
ℒm =KK K ΔURd − ΓURm
|pg|
RqU)J
pg
UqJ
r
dqS
ℒs = KK𝑟𝑎𝑛𝑘(𝑆Ud)pg
UqJ
r
dqS
Experiment
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Vertex Classification
Experiment
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Link Prediction
Experiment
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Network Visualization
Outline
q HierarchicalInfocanbeobservedtoacertainextentinonlinenetworks.
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Explicit hierarchy with attributes Implicit hierarchy with tags
#
#University
#Major
#EnrollmentYear
TwitterNetworkFacebook Network
Tag2Gauss:LearningTagRepresentationsviaGaussianDistributioninTaggedNetworks
LunD𝐮∗,YunWan𝑔∗,GuojieSon𝑔∱ ,XiaoMa,LichenJin,WeiLin,FeiSun.Tag2Gauss: LearningTagRepresentationsviaGaussianDistributioninTaggedNetworks.InProceedingsofIJCAI,2019.
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HowtoRepresent?
q Representtagsandnodessimultaneouslyq Tagsrepresentnodecommunitieswithintricateoverlappingrelationships
q Distribution:Tag;Samplefromdistributions:Node
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Howtolearn?
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q Tag2Gauss Framework:
§ Tag-view Embedding § Node-view Embedding § Multi-task Learning
Tag View Embedding Module Node View Embedding Module
MaxMargin Ranking Objective NCE Objective+=Objective
...
Forward
Backward
GCN
...
NodeTag
MultiTask Learning
...
Tag Relation Sequence
ProjectHybrid
Walker
Tag Distribution
Sample
...
Experiments
q Datasets:§ Leetcode (652nodes,1096edges,34tags,3labels)§ Bilibili (11727nodes,187148edges,151tags,10labels)§ Cora.(2707nodes,5429edges,1433tags,7labels)
q Baselines§ DeepWalk (KDD’14)§ Node2vec(KDD’16)§ HybridDeepwalk (NaiveDesign)§ GraphSage (NIPS’17)
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Experiment
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The Advantage of Distribution Representations
Segment Tree
ArrayLinked List
DFS
Topological SortDivide and Conquer
Rejection SamplingQueue
TrieDP
Binary Indexed TreeTwo Pointers
Tree RecursionHeap
Sort
BinarySearch
Bit Manipulation
Greedy
Backtracking
BSTMinimax
Brainteaser
Segment TreeArray
Linked List DFS
Topological Sort
Divide and ConquerRejection Sampling
TrieDP
Binary Indexed TreeTwo Pointers
Recursion
Bit Manipulation
BSTBacktracking
Sort
BinarySearch
Minimax
Brainteaser
Greedy
HeapQueue
Tree
Experiment
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Node Classification
MainContents
q Background
q Graphembeddingwithhierarchicalcommunitystructure
q Domainadaptivegraphembedding
q Futureworks
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DANE:DomainAdaptiveNetworkEmbedding
YizhouZhang, GuojieSon𝑔∱ ,LunDu,Shuwen Yang,Yilun Jin.DANE:DomainAdaptiveNetworkEmbedding.InProceedings ofIJCAI,2019.
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Motivation
q Domainadaptation§ Transferringmachinelearningmodelsacrossdifferentdatasetsto
handlethesametaskq Domainadaptationonnetworksissignificant:
§ Reducethecostoftrainingdownstreammachinelearningmodelsbyenablingmodelstobereusedonothernetworks
§ Handlethescarcityoflabeleddatabytransferringmodelstrainedwellonalabelednetworktounlabelednetworks
q Itisimportanttodesignanetworkembeddingalgorithmthatcansupportdomainadaptation.
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Challenges
q Embeddingspacealignment§ Structurallysimilarnodesshouldhavesimilarrepresentationsintheembeddingspace,eveniftheyarefromdifferentnetworks.
q Distributionalignment§ Embeddingvectorsofdifferentnetworksshouldhavesimilardistributioninembeddingspace.
§ Mostmachinelearningmodelsperformasguaranteedonlywhentheyworkondatawithsimilardistributionastheirtrainingdata.
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TechniqueFramework:Overall
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AdversarialLearningRegularization
q Discriminatortoavoidtheinstabilityofadversariallearning:
q Adversarialtraininglossfunctiontoconfusethediscriminatoris:
qOveralllossfunction
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Experiment
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Comparison with Baselines
Experiment
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Comparison with the Variant without adversarial learning
MainContents
q Background
q Graphembeddingwithhierarchicalcommunitystructure
q Domainadaptivegraphembedding
q Futureworks
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FutureWorks
q Understandingofgraphneuralnetworks§ Whydoesitwork?
§ Whatkindofgraphisitmoreeffective?
q CustomizedGNNfordifferentkindsofgraphsq Applications
§ Semi-structureddatamining
§ Sourcecodeanalytics
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Q&A
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