CS 789 THEORY SEMINAR [home]
Speaker: Lisa Fleischer
Affiliation: IBM TJ Watson Research Center
Date: January 24,
2004
Title: Tolls for
heterogeneous, selfish users of a multicommodity network and generalized
congestion games
Abstract: In
traffic networks, transit delay is a function of congestion. To provide a
sufficient quality of service to customers, one goal of a network owner may be
to have traffic that minimizes total, or average, system delay. On the other
hand, if customers can choose their own routes, they would naturally seek routes
that minimize their individual delay. The traffic pattern that results from
customers acting ``selfishly'' may result in overall higher system-wide delay. A
natural question
is: how can a network owner influence selfish network users to independently
choose a traffic pattern that minimizes system-delay?
One natural approach is to charge network users for use of each link in the
network via tolls. In this setting, each user selects a path that minimizes some
function of delay plus tolls. Each user may have a different preference for
delay versus toll. In such a setting, we give a complete characterization of
traffic patterns that can be induced via tolls. These include patterns that
minimize mean delay, mean weighted delay, and maximum delay. Our proof is
constructive --- yielding a polynomial time algorithm --- and extends to general
congestion games.
This is joint work with Kamal Jain and Mohammad Mahdian.