Donald Gross, PhD, is Distinguished Research Professor of Operations Research and Engineering at George Mason University and Professor Emeritus of Operations Research at The George WashingtonUniversity. With over forty years of experience in academia and consulting, Dr. Gross has published extensively in the area of queueing applications to repairable item inventory control, air traffic control, and Internet congestion. JOHN F. SHORTLE, PhD, is¿Associate Professor in the Department of Systems Engineering and Operations Research at George Mason University. He has authored or coauthored over thirty published articles on the application of simulation and queueing theory in telecommunications and aviation. JAMES M. THOMPSON is an Enterprise Architect at the Federal Home Loan Mortgage Corporation. His current areas of research interest include computer system performance modeling, system capacity studies and benchmarking, information architecture, and computational finance. The Late CARL M. HARRIS, PhD, was BDM International Professor and the founding chair of the Systems Engineering and Operations Research Department at George Mason University. For his research contributions to the areas of applied probability and statistics, queueing theory, simulation, and public systems analysis, Dr. Harris was awarded the George E. Kimball Medal by the Institute for Operations Research and the Management Sciences (INFORMS) in 1999.