@conference {1500060,
	title = {Imbalanced Collusive Security Games },
	booktitle = {Conference on Decision and Game Theory for Security (GameSec)},
	year = {2018},
	abstract = {Colluding adversaries is a crucial challenge for defenders in many
real-world applications. Previous literature has provided Collusive Security Games
(COSG) to model colluding adversaries, and provided models and algorithms to
generate defender strategies to counter colluding adversaries, often by devising
strategies that inhibit collusion [6]. Unfortunately, this previous work focused
exclusively on situations with perfectly matched adversaries, i.e., where their
rewards were symmetrically distributed. In the real world, however, defenders
often face adversaries where their rewards are asymmetrically distributed. Such
inherent asymmetry raises a question as to whether human adversaries would attempt to collude in such situations, and whether defender strategies to counter
such collusion should focus on inhibiting collusion. To address these open questions, this paper: (i) explores and theoretically analyzes Imbalanced Collusive
Security Games (ICOSG) where defenders face adversaries with asymmetrically
distributed rewards; (ii) conducts extensive experiments of three different adversary models involving 1800 real human subjects and (iii) derives novel analysis
of the reason behind why bounded rational attackers models outperform perfectly
rational attackers models. The key principle discovered as the result of our experiments is that: careful modeling of human bounded rationality reveals a key difference (when compared to a model using perfect rationality) in defender strategies
for handling colluding adversaries which face symmetric vs asymmetric rewards.
Whereas a model based on perfect rationality always attempts to break collusion
among adversaries, a bounded rationality model acknowledges the inherent difficulty of breaking such collusion in symmetric situations and focuses only on
breaking collusion in asymmetric situation, and only on damage control from
collusion in the symmetric situation.},
	author = {Ou, Han-Ching and Tambe, Milind and Dilkina, Bistra and Vayanos, Phebe}
}
