Wednesday, November 2, 2016
7:00 pm EST (informal reception)
7:30 pm EST (presentation)
Morison Hall, Room 220
175 Forest Street
Waltham, MA 02452
Finding Online Extremists in Social Networks
Professor Tauhid Zaman
Massachusetts Institute of Technology
Online extremists in social networks pose a new form of threat to the general public. These extremists range from cyberbullies who harass innocent users to terrorist organizations such as ISIS that use social networks to spread propaganda. Currently social networks suspend the accounts of such extremists in response to user complaints. For instance, in 2016 alone Twitter has shut down over 360,000 ISIS related accounts. The challenge is that these extremist users simply create new accounts and continue their activities. It is a never ending battle. In this talk we present a new set of operational capabilities to deal with the threat posed by online extremists in social networks.
Using data from several hundred thousand extremist accounts on Twitter, we develop a behavioral model for these users, in particular what their accounts look like and who they connect with. This model is used to identify new extremist accounts by predicting if they will be suspended for extremist activity. We also use this model to track existing extremist users as they create new accounts by identifying if two accounts belong to the same user. Finally, we present a model for searching the social network to efficiently find suspended users’ new accounts based on a variant of the classic Polya’s urn setup. We find a simple characterization of the optimal search policy for this model under fairly general conditions. Our urn model and main theoretical results generalize easily to search problems in other fields.
Speaker Biography: Professor Zaman is the KDD Career Development Professor in Communications and Technology MIT Sloan School of Management. He received his BS, MEng, and PhD degrees in electrical engineering and computer science from MIT. His research interest is in behavioral analytics, with a focus on solving operational problems using behavioral models, modern statistical methods, and network algorithms. His work has been featured in Wired, Mashable, the LA Times, and Time Magazine.