A Terrain Reasoning Algorithm to Defend a Fire Zone Abstract: Distributed simulation is an approach to building large-scale simulation models from a set of independent simulator nodes communicating via a network. The U. S. Army uses distributed simulation systems for training and analysis. Those systems can include both crewed simulators and computer generated forces (CGF) systems; the latter use software, rather than human crews, to generate the behavior of entities in the simulated battlefield. CGF systems must include algorithms for all of the tactical behaviors that are needed for the simulation. One such tactical behavior is "Fire Zone Defense". An algorithm for this behavior must select defensive deployment locations on the terrain for the individual entities (e.g., tanks) of a unit (e.g., a company) to effectively defend an assigned engagement area. The entities of the unit then move to the selected locations. We developed a new algorithm for this behavior. It combines a geometric terrain analysis algorithm, which creates a weighted graph representation of the terrain, with a greedy optimization algorithm that operates on that graph. The algorithm was compared experimentally with a previously existing algorithm for the same behavior. The comparison used a metric that measured the cumulative observation of the engagement area from the selected locations of the defending entities. Under that metric the new algorithm consistently outperformed the existing algorithm, with an average ratio of performance over 2. The execution speeds for the two algorithms were approximately the same. Biography Mikel D. Petty is Chief Scientist of the Virginia Modeling, Analysis and Simulation Center of Old Dominion University. He worked previously at the University of Central Florida?s Institute for Simulation and Training. He has been performing and leading modeling and simulation research since 1990. He received a Ph.D. from the University of Central Florida (UCF) in 1997, an M.S. from UCF in 1988, and a B.S. from the California State University Sacramento in 1980, all in Computer Science. His research interests are in distributed simulation interoperability, computer generated forces, multi-resolution simulation, and applications of computational geometry in simulation. During 9 years in the research field he has published 70 research papers in thos= e areas and has been awarded over 30 research contracts. -------------------------------------------------------- Mikel D. Petty, Ph.D. Chief Scientist Virginia Modeling, Analysis & Simulation Center College of Engineering and Technology Old Dominion University 7000 College Drive, Suffolk VA 23435 Office 757-686-6210 Fax 757-686-6214 Cell 757-286-7246 Email mpetty@vmasc.odu.edu --------------------------------------------------------