  We present a model for layered security with applications to the protection
of sites such as stadiums or large gathering places. We formulate the problem
as one of maximizing the capture of illegal contraband. The objective function
is indefinite and only limited information can be gained when the problem is
solved by standard convex optimization methods. In order to solve the model, we
develop a dynamic programming approach, and study its convergence properties.
Additionally, we formulate a version of the problem aimed at addressing
intelligent adversaries who can adjust their direction of attack as they
observe changes in the site security. Furthermore, we also develop a method for
the solution of the latter model. Finally, we perform computational experiments
to demonstrate the use of our methods.
