Core Concepts
The defender can preemptively allocate information-gathering resources to reduce uncertainty about the attacker's costs and intentions, and then optimally allocate defensive resources given the acquired information.
Abstract
The paper presents a two-stage game-theoretic framework for modeling two-player noncooperative games where one player (the defender) has uncertainty about the costs of the game and the other player's (the attacker's) intentions.
In Stage 1, the defender allocates information-gathering resources to reduce this uncertainty. The relationship between the information-gathering resources and the signal received by the defender is parametrized by a decision variable r.
In Stage 2, the defender receives a signal σ that provides limited information about the true state of the world ω, and then both players play a noncooperative game. The defender's decision x1 is a function of the received signal σ, while the attacker's decision x2 is a function of both the signal σ and the true state of the world ω.
The authors provide a gradient-based algorithm to solve this two-stage game and apply the framework to a tower defense game, which can be interpreted as a variant of a Colonel Blotto game with smooth payoff functions and uncertainty over battlefield valuations. They analyze how the optimal decisions shift with changes in information-gathering allocations and perturbations in the cost functions.
The key insights are:
The Stage 1 cost landscape can be relatively flat, leading to optimal scout allocations at the vertices of the simplex (completely removing uncertainty about one world).
In the complete information cases (σ ≠ 0), the defender's optimal policy is to allocate all resources in the attacker's preferred direction.
In the incomplete information case (σ = 0), the defender's policy becomes more biased towards the riskier direction as the cost differential between worlds increases.
Stats
The attacker preference matrix B is defined as:
B = [
3.0 2.0 2.0
2.0 3.0 2.0
2.0 2.0 3.0
]
The perturbed preference matrix Bθ is defined as:
Bθ = [
3.0 + θ 2.0 2.0
2.0 3.0 2.0
2.0 2.0 3.0
]
where θ = 2.