Events Calendar

Annenberg Research Seminar

Speaker: Kristina Lerman, Information Sciences Institute

Talk Title: The Dynamics of Information Spread on Networks

Abstract: "The recent proliferation of data about human behavior on social media sites offers a natural laboratory for studying social dynamics, specifically how the structure of social networks affects the flow of information and influence. I will present recent results of the study of information spread on the social news aggregator Digg. By carrying out quantitative analysis of information cascades on the Digg follower graph, we have observed cascades that spread fast enough for one initial seed to “infect” hundreds of people, yet end up affecting only 0.1% of the entire network. This conflicts with our understanding of the spread of epidemics on networks, which suggests the existence of an epidemic threshold below which epidemics die out and above which they spread to a significant fraction of the network. I demonstrate that while the highly clustered structure of the Digg network somewhat slows the overall growth of cascades, the far more dramatic effect is created by the contagion mechanism, which deviates from standard social contagion models.”

In the second part of the talk, “I argue that many dynamic processes on social networks, such as the spread of information or disease, cannot be modeled as a random walk. I classify dynamic processes as conservative and non-conservative, based on whether they conserve some diffusing quantity, and show how these differences impact the choice of metrics used for network analysis. I show that Alpha-Centrality, which mathematically describes non-conservative epidemic spread, leads to better, empirically verifiable insights into the structure and behavior of online social networks than conservative metrics, such as PageRank.”

Biography: Kristina Lerman is a Project Leader at the Information Sciences Institute and holds a joint appointment as a Research Assistant Professor in the USC Viterbi School of Engineering's Computer Science Department. Her research focuses on applying network- and machine learning-based methods to problems in social computing.

She also was principal organizer of the 2008 American Association for the Advancement of Artificial Intelligence (AAAI) Social Information Processing Symposium.

Host: Annenberg Networks Network

More Info: http://annenberg.usc.edu/Events/2011/110926ARSKristinaLerman.aspx

Location: Annenberg School For Communication (ASC) - 207 (Geoffrey Cowan Forum)

Audiences: Everyone Is Invited

Contact: Eric Mankin

Event Link: http://annenberg.usc.edu/Events/2011/110926ARSKristinaLerman.aspx