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1 1 Chenhao Tan, 1 Jie Tang, 2 Jimeng Sun, 3 Quan Lin, 4 Fengjiao Wang 1 Department of Computer Science and Technology, Tsinghua University, China 2 IBM TJ Watson Research Center, USA 3 Huazhong University of Science and Technology, China 4 Beijing University of Aeronautics and Astronautics, China Social Action Tracking via Noise Tolerant Time-varying Factor Graphs
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2 Outline Motivation Approach Experiment Conclusion & Future Work
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3 Motivation 500 million users the 3 rd largest “Country” in the world More visitors than Google Action: Update statues, create event More than 4 billion images Action: Add tags, Add favorites 2009, 2 billion tweets per quarter 2010, 4 billion tweets per quarter Action: Post tweets, Retweet
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4 User Action in Social Networks Add photo to her favorites Post tweets on “Haiti Earthquake” Publish in KDD Conference TwitterFlickr Arnetminer
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5 User Action in Social Networks Questions: -What factors influence you to add a photo into your favorite list? - If you post a tweet on “Haiti Earthquake”, will your friends retweet it or reply? Challenge: - How to track and model users’ actions? - How to predict users’ actions over time?
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6 John Time t John Time t+1 Action Prediction : Will John post a tweet on “Haiti Earthquake”? Action Prediction : Will John post a tweet on “Haiti Earthquake”? Attributes: 1.Always watch news 2.Enjoy sports 3. …. Influence 1 Personal attributes 4 Dependence 2 Complex Factors Correlation 3
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7 Problem formulation G t =(V t, E t, X t, Y t ) Input: G t =(V t, E t, X t, Y t ) t = 1,2,…T Output: F: f(G t ) ->Y t Nodes at time t Edges at time t Attribute matrix at time t Actions at time t
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8 NTT-FGM Model Continuous latent action state Personal attributes Correlation Dependence Influence Action Personal attributes
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9 How to estimate the parameters? Model Instantiation
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10 Model Learning Extremely time costing!! Our solution: distributed learning (MPI)
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11 Most Time-costing –Compute the gradients Distributed Learning
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12 Data Set Baseline –SVM –wvRN (Macskassy, 2003) Evaluation Measure: Precision, Recall, F1-Measure ActionNodes#EdgesAction Stats Twitter Post tweets on “Haiti Earthquake” 7,521304,275730,568 Flickr Add photos into favorite list 8,721485,253 Arnetminer Issue publications on KDD 2,06234,9862,960 Experiment
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13 Performance Analysis
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14 Factor Contribution Analysis NTT-FGM: Our model NTT-FGM-I: Our model ignoring influence NTT-FGM-CI: Our model ignoring influence and correlation
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15 Efficiency Performance
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16 Conclusion Formally formulate the problem of social action tracking Propose a unified model: NTT-FGM to simultaneously model various factors Present an efficient learning algorithm and develop a distributed implementation Validate the proposed approach on three different data sets, and our model achieves a better performance
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17 Thank you ! QA? Data & Code: http://arnetminer.org/stnthttp://arnetminer.org/stnt Welcome to our poster!
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18 Statistical Study: Influence Y-axis: the likelihood that the user also performs the action at t X-axis: the percentage of one’s friends who perform an action at t − 1
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19 Statistical Study: Dependence Y-axis: the likelihood that a user performs an action X-axis: different time windows
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20 Statistical Study: Correlation Y-axis: the likelihood that two friends(random) perform an action together X-axis: different time windows
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21 Appendix
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22 Appendix
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23 Appendix
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24 Prediction Based on the learning parameters we just need to solve the following equations:
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25 Latent State Analysis Action Bias Factor: f(y 1 2 |z 1 2 ) Influence Factor: g(z 1 1,z 1 2 ) Correlation Factor: h(z 1 2,z 2 2 ), h(z 1 2,x 1 2 )
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