Solving defender-attacker-defender models for infrastructure defense

Abstract This paper (a) describes a defender-attacker-defender sequential game model (DAD) to plan defenses for an infrastructure system that will enhance that system’s resilience against attacks by an intelligent adversary, (b) describes a realistic formulation of DAD for defending a transportation network, (c) develops a decomposition algorithm for solving this instance of DAD and others, and (d) demonstrates the solution of a small transportation-network example. A DAD model generally evaluates system operation through the solution of an optimization model, and the decomposition algo-rithm developed here requires only that this system-operation model be continuous and convex. For example, our transportation-network example incorporates a conges-tion model with a (convex) nonlinear objective function and linear constraints. Keywords infrastructure defense; infrastructure protection; homeland defense; intelligent adver-sary; game theory; optimization; defender-attacker-defender model; trilevel game; Stackelberg game; probabilistic risk analysis; traffic equilibrium 1