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Models of Communication Dynamics for Simulation of Information Diffusion. Malik Magdon-Ismail , Konstantin Mertsalov, Mark Goldberg. Motivation. Important to understand information diffusion in social networks Viral marketing, gossip, rumors, etc. Social Networks are dynamic
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Models of Communication Dynamics for Simulation of Information Diffusion Malik Magdon-Ismail, Konstantin Mertsalov, Mark Goldberg
Motivation • Important to understand information diffusion in social networks • Viral marketing, gossip, rumors, etc. • Social Networks are dynamic • Edges and nodes change with time. • Cannot repeat historical dynamics, so need to simulate dynamics for research.
LiveJournal Data Alice’s Blog Bill’s Blog Alice Posted Bill Posted A • Bill commented • Alice commented • Cory • commented Edges: (A,B); (C,B) (D,B) • Alice commented • Cory commented • Dave commented Edges: (B,A); (C,A) D B C Construct sequence of comment graphs (every week)
Dynamics of LiveJournal Network • 60 weeks • Per week: • 153,028 nodes • 510,317 edges • Very dynamic: • 70% of edges change from week to week
Diffusion in Dynamic Networks Time: T Time: T+1 Time: T+2 C C C C C A A A A A B B B B B D D D D D F F F F F E E E E J J J J E J Static H H H H H G G G G G C A B D Dynamic F E J H G
Diffusion in LiveJournal Blogs Linear Threshold Independent Cascade Diffusion model and network dynamics have a big impact on infection.
Goal Can we model the network dynamics so that diffusion in the model mimics diffusion in the real network?
Modeling Dynamics Output Network at iteration t+1 Input Network at iteration t C C A A B D B D E J E J F F H H G G
A General Model Input: Gt Step 1: Find Locality C C A A B D B D F E J F E J H H G G Step 2:Local Attachment Output: Gt+1 C A C B D A B D F E J F E J H G H G
Ingredients to General Model 1. What is the locality of the node ? C A • Global: all nodes • k-Neighborhood • Community* B D Gt F E J H G 2. How to attach within locality ? C A B D • Uniform • Preferential Attachment • Random walk Gt+1 F E J H G * Community = union of overlapping clusters [Baumes, Goldberg, Magdon-Ismail 2005]
Diffusion Models C C Linear Threshold: • Node i has a susceptibility fraction T(i). • Node i infected if at least T(i) neighbors are infected. A A B B D D F F E E J J H H G G C C A A Independent Cascade: • Every edge (i,j) has transmission prob. P(i,j). • Nodes have one chance to infect neighbors. B B D D 0.3 0.2 F F E E J J 0.4 H H G G
Diffusion in Dynamic Network Diffusion Model Network Dynamics Real LiveJournal Cascade Diffusion Progression Locality and Attachment Threshold Model
Results Dynamic Network Static Aggregated Network Cascade Threshold
Conclusions • Dynamics of the network strongly affects it’s diffusion properties • Global random link dynamics does not model dynamics correctly • Social network links evolve through locality (social groups), eg. cluster-based communities+PA produces diffusion faithful network dynamics.