News/Events

Friday, Feb 17, 2012

UMass CSSI Seminar Series

Athina Markopoulou

12:30 PM - 2:00 PM

Sampling Online Social Networks

Computer Science Building, Room 150/151

In this seminar, from the Computational Social Science Initiative, Athina Markopoulou from the University of California, at Irvine, will present on the following topic:

"Online Social Networks (OSNs) have recently emerged as a new Internet killer-application and are of interest to a range of communities, ranging from computer science and engineering to social sciences. OSNs are widely studied today based on samples collected through measurement of publicly available information. In this talk, I will give an overview of our recent work on sampling online social networks. First, I will describe a framework for obtaining a probability sample of users by crawling the friendship graph. I will provide practical recommendations including the choice of crawling technique, the use of online convergence diagnostics, and implementation issues. Second, I will introduce multigraph sampling - a technique that exploits different relations between users to efficiently sample users, even when the friendship graph exhibits poor connectivity or slow mixing. Third, I will present the stratified weighted random walk (S-WRW) - an efficient heuristic that preferentially crawls those nodes and edges that convey greater information pertaining to the target metric. Finally, I will report results from applying our techniques to real-life OSNs, such as Facebook and Last.FM, and from studying their characteristics, including user attributes and structural properties."

Lunch will be provided. 

For more information see the CSSI's website.