Structual Trend Analysis for Online Social Networks

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Post on 24-Feb-2016




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Structual Trend Analysis for Online Social Networks. Ceren Budak Divyakant Agrawal Amr El Abbadi Science,UCSB SantaBarbara,USA Reporter: Qi Liu. What to do?. traditional. Trend. coordinate. structural. uncoordinate. Whats new?. Structural trend definition - PowerPoint PPT Presentation


Structual Trend Analysis for Online Social Networks

Structual Trend Analysis for Online Social NetworksCeren Budak Divyakant Agrawal Amr El AbbadiScience,UCSB SantaBarbara,USAReporter: Qi LiuWhat to do?TrendtraditionalstructuralcoordinateuncoordinateWhats new?Structural trend definitionReducing to local triangles countingSampling tech for online detectionFrom where?A temporal viewUsing spatial propertiesCounting, streaming and semi-streamingDefine it!High scores for coordinated trendLarge number of pairs of connected nodesLarge number of mentionsFor a complete graph, favors a uniform distributionIn a power law graph, biased toward influential nodes

Example for complete graphf(Tx) = f(Ty) = 2Ng(Tx) = 3N(N-1) g(Ty) = 4N(N-1)1N+12222TxTy11Example for power law graphf(Tx) = f(Ty) = K+N-1g(Tx) = 2K(N-1) g(Ty) = 2K+2N-4TxTyK111111KSignificance ValidationModel-Based ValidationIndependent Trend Formation Modelpi,x: external influenceqi,j,x: internal influenceNearest Neighbor modelu: probability from 2 to 1k: pairs of connected nodes per stepAnalysis-Based ValidationCoordinated differs from traditionalSpearman rank correlation coefficient(SRCC) [-1, +1]Average precision difference

What topics detected?Vary p and qUsing different score functionsResults:

App: Sybil Attack DetectionRanking of Ty: co>tr>unBreakpoints may means attackSmall p,q and few Sybil nodes, big effect

Analysis-Based ValidationTwitter data: 467 million posts, 20 million users, spanning 7 months

230m posts, 2.7m users, 2960495 hashtagsExtractionTr vs Co vs Un

Something new about twitter dataChoose 60th to 100th topicsFindings: coordinated trend: 7694 users, 21.5 edges on average; uncoordinated trend: 21114 users, 8.6 edges

PrefuseHashtag categories effect7 categories: political, technology, celebrity, games, idioms, movies, music and none

Incremental Counting AlgorithmFor a coming

Reducing to count local trianglesA directed multi-graph G = (N,E)N = T U N, E = Et U Ef

Sampling tech

ConclusionTwo trend definitonsA reductionSampling techThe ENDTHANKS!