@conference {1506762,
	title = {IRIS - A Tool for Strategic Security Allocation in Transportation Networks },
	booktitle = {The Eighth International Conference on Autonomous Agents and Multiagent Systems - Industry Track},
	year = {2009},
	abstract = {Security is a concern of major importance to governments and companies throughout the world. With limited resources, complete coverage of potential points of attack is not possible. Deterministic allocation of available law enforcement agents introduces predictable
vulnerabilities that can be exploited by adversaries. Strategic randomization is a game theoretic alternative that we implement in
Intelligent Randomization In Scheduling (IRIS) system, a software
scheduling assistant for the Federal Air Marshals (FAMs) that provide law enforcement aboard U.S. commercial flights.
In IRIS, we model the problem as a Stackelberg game, with
FAMS as leaders that commit to a flight coverage schedule and
terrorists as followers that attempt to attack a flight. The FAMS
domain presents three challenges unique to transportation network
security that we address in the implementation of IRIS. First, with
tens of thousands of commercial flights per day, the size of the
Stackelberg game we need to solve is tremendous. We use ERASERC, the fastest known algorithm for solving this class of Stackelberg
games. Second, creating the game itself becomes a challenge due
to number of payoffs we must enter for these large games. To address this, we create an attribute-based preference elicitation system to determine reward values. Third, the complex scheduling
constraints in transportation networks make it computationally prohibitive to model the game by explicitly modeling all combinations
of valid schedules. Instead, we model the leader{\textquoteright}s strategy space
by incorporating a representation of the underlying scheduling constraints.
The scheduling assistant has been delivered to the FAMS and is
currently undergoing testing and review for possible incorporation
into their scheduling practices. In this paper, we discuss the design
choices and challenges encountered during the implementation of
IRIS.},
	author = {Tsai, Jason and Shyamsunder Rathi and Kiekintveld, Christopher and Ordonez, Fernando and Tambe, Milind}
}
