1. Trust, Influence and Bias in Social Media Anupam Joshi Joint work with Tim Finin and several students Ebiquity Group, UMBC [email_address] http://ebiquity.umbc.edu/
15. Social Media Graphs Links Between Nodes Links Between Nodes and Tags Simultaneous Cuts
16. A community in the real world is identified in a graph as a set of nodes that have more links within the set than outside it and share similar tags. Communities in Social Media
17. Nodes Nodes Nodes Tags Tags Nodes Tags Tags Fiedler Vector Polarity β = 0 Entirely ignore link information β = 1 Equal importance to blog-blog and blog-tag, β >> 1 NCut WebKDD ‘08 SimCUT: Clustering Tags and Graphs
18. SimCUT: Clustering Tags and Graphs β = 0 Entirely ignore link information β = 1 Equal importance to blog-blog and blog-tag, β >> 1 NCut Clustering Only Links Clustering Links + Tags WebKDD ‘08
21. Varying Scaling Parameter β Accuracy = 36% Accuracy = 62% Higher accuracy by adding ‘tag’ information Simple Kmeans ~23% Content only, binary Content only ~52% (Getoor et al. 2004) β >> 1 β=1 β=0 Accuracy = 39% Only Graph Only Tags Graphs & Tags
22.
23. Influence in Communities http://instapundit.com http://michellemalkin.com/ http://dailykos.com http://crooksandliars.com http://volokh.com http://rightwingnews.com Communities detected using “Fast algorithm for detecting community structure in networks”, M.E. J. Newman