CATS-Apr-19-2013
Title[edit]
Risk in network routing games
Speaker[edit]
Evdokia Nikolova is an Assistant Professor at the Computer Science & Engineering Department at Texas A&M University. Previously she was a postdoctoral associate in the Computer Science and Artificial Intelligence Laboratory at MIT. She graduated with a BA in Applied Mathematics with Economics from Harvard University, MS in Mathematics from Cambridge University (U.K.) and Ph.D. in Computer Science from MIT. She is interested in risk analysis from an algorithmic perspective arising in stochastic optimization, networks, economics and complex systems. She has worked on applications to transportation and is also interested in energy and other domains where her work may apply.
Abstract[edit]
Network routing games are instrumental in understanding traffic patterns and improving congestion in networks. They have a direct application in transportation and telecommunication networks and extend to many other applications such as task planning, etc. Theoretically, network games were one of the central examples in the development of algorithmic game theory.
In these games, multiple users need to route between di fferent source-destination pairs and links are congestible, namely, each link delay is a non-decreasing function of the flow on the link. Many of the fundamental game theoretic questions are now well understood for these games, for example, does equilibrium exist, is it unique, can it be computed e fficiently, does it have a compact representation; the same questions can be asked of the socially optimal solution that minimizes the total user delay.
So far, most research has focused on the classical models in which the link delays are deterministic. In contrast, real world applications contain a lot of uncertainty, which may stem from exogenous factors such as weather, time of day, weekday versus weekend, etc. or endogenous factors such as the network tra ffic. Furthermore, many users are risk-averse in the presence of uncertainty, so that they do not simply want to minimize expected delays and instead may need to add a bu ffer to ensure a guaranteed arrival time to a destination.
I present my recent work on a new stochastic network game model with risk-averse users. Risk-aversion poses a computational challenge and it often fundamentally alters the mathematical structure of the game compared to its deterministic counterpart, requiring new tools for analysis. The talk will discuss best response and equilibrium analysis, as well as equilibrium efficiency (price of anarchy) and a new concept, the price of risk.
One relevant paper is here: http://faculty.cse.tamu.edu/nikolova/papers/Stochastic-selfish-routing-full.pdf
A short summary of the paper is here: http://www.sigecom.org/exchanges/volume_11/1/NIKOLOVA.pdf
