Event
MBSE/Advanced Networks Colloquium: Guodong Shi, "Opinion Dynamics over Signed Social Networks"
Monday, May 2, 2016
11:00 a.m.
1146 AV Williams Building
Kim Edwards
kedwards@umd.edu
Combined Model-Based Systems Engineering and Advanced Networks Colloquium
Opinion Dynamics over Signed Social Networks
Guodong Shi
Lecturer and Future Engineering Research Leadership Fellow
Australian National University
(roundtable: 2:00 p.m., 1146 AV Williams Bldg)
Host: John Baras
Abstract
This talk will discuss evolution of opinions over a social network modeled as a signed graph. The sign attached to an edge in this graph characterizes whether the corresponding individuals or end nodes are friends (positive links) or enemies (negative links). Pairs of nodes are randomly selected to interact over time, and when two nodes interact, each of them updates its opinion based on the opinion of the other node and the sign of the corresponding link. This model generalizes the Degroot model to account for negative links: when two adversaries interact, their opinions go in opposite directions. Conditions are provided for convergence and divergence in expectation, in mean-square, and in almost sure sense, which exhibit phase transition phenomena for these notions of convergence. We establish a no-survivor theorem, stating that the difference in opinions of any two nodes diverges whenever opinions in the network diverge as a whole. We also prove a live-or-die lemma, indicating that almost surely, the opinions either converge to an agreement or diverge. Finally, we extend our analysis to cases where opinions have hard lower and upper limits. In these cases, we study when and how opinions may become asymptotically clustered to the belief boundaries and highlight the crucial influence of structural balance of the underlying network on this clustering phenomenon.
Biography
Guodong Shi is a Lecturer and Future Engineering Research Leadership Fellow at the College of Engineering and Computer Science, The Australian National University, Canberra, Australia. He received his Ph.D. in Systems Theory from the Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China, in July 2010. From Aug. 2010 to Apr. 2014 he was a postdoctoral researcher at the ACCESS Linnaeus Centre, School of Electrical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden. His research interests include social opinion dynamics, distributed control systems, and quantum networking and decisions.
