An Interdiction Model for Sparsely Traveled Networks.

An algorithm and FORTRAN IV computer program for choosing locations at which to place assault forces to prevent infiltrators from proceeding through a transportation or supply network. Interdiction is by direct assault rather than by reducing the throughput capacity of a supply network. The model assumes that the strategy for placing forces is known to the infiltrator and that he will choose a path through the network that maximizes his probability of successful traverse. Inputs to the model are a list of the arcs and nodes of the network, the number of forces available to stop the infiltrator, and the probabilities for stopping him at the arcs and nodes as functions of the number of forces placed there. The model calculates the optimal placement when one force is available, and the optimal or nearly optimal placement of forces when multiple forces are available. The computer program, written to implement the model on RAND's IBM 7044, can readily be adapted to other high-speed computers. It now handles problems with up to 300 arcs, 150 nodes, and 25 forces, and can easily be modified by changing the dimension statement. 50 pp. Ref.