Kevin Wood

Analysis of electric grid security under terrorist threat

We describe new analytical techniques to help mitigate the disruptions to electric power grids caused by terrorist attacks. New bilevel mathematical models and algorithms identify critical system components (e.g., transmission lines, generators, transformers) by creating maximally disruptive attack plans for terrorists assumed to have limited offensive resources. We report results for standard reliability test networks to show that the techniques identify critical components with modest computational effort.

Worst-Case Interdiction Analysis of Large-Scale Electric Power Grids

This paper generalizes Benders decomposition to maximize a nonconcave objective function and uses that decomposition to solve an ldquoelectric power grid interdiction problem.rdquo Under one empirically verified assumption, the solution to this bilevel optimization problem identifies a set of components, limited by cardinality or ldquointerdiction resource,rdquo whose destruction maximizes economic losses to customers (and can thereby guide defensive measures). The decomposition subproblem typically incorporates a set of DC optimal power-flow models that cover various states of repair after an attack, along with a load-duration curve. Test problems describe a regional power grid in the United States with approximately 5000 buses, 6000 lines, and 500 generators. Solution time on a 2-GHz personal computer is approximately one hour.

Anatomy of a Project to Produce a First Nuclear Weapon

We describe the industrial project that a “proliferator” would conduct to produce a first, small batch of nuclear weapons. From refining yellowcake ore to final weapons assembly, we highlight the projects tasks and their interactions. The proliferator can choose alternative production technologies that offer quicker completion, but at higher cost in terms of limited resources. The proliferator can also expedite his project by devoting more resources to critical tasks. From physics and chemistry, we determine raw material requirements. From industrial engineering and materials science, we convert these requirements into estimates of the time, manpower, energy, and money required to complete each task under normal and expedited conditions. Using generalized project-management analysis tools, we then estimate the earliest possible completion time of the project, assuming two different levels of resource availability. We also estimate the time required to complete a weapon if some of the projects steps can be skipped; for example, if the proliferator acquires stolen, highly enriched uranium metal.

A Game-Theoretic Model for Defense of an Oceanic Bastion Against Submarines

Abstract : We develop a game-theoretic model called BASTION to guide the employment of antisubmarine warfare (ASW) platforms such as ships and aircraft that are defending a stationary oceanic bastion from attack by hostile submarines. The model is an example of a two-person zero-sum game with some additional variables (ship locations) that are under the control of the maximizing defender, but known to the minimizing attacker. The attacker knowing the ship locations, but not the locations of other platforms such as aircraft, must select a path to the bastion. The probability of detecting the attacker as it follows this path is the objective shared by the opponents.