Jack H. Sheehan received B.S. degrees in nuclear engineering and in electrical engineering from Texas A&M University in College Station, TX, in 1981. He received an M.S. degree in electrical and computer engineering from the University of Texas at Austin in 1990, where he is currently pursuing a Ph.D. degree.From 1981 to 1985, Lt. Sheehan served a tour of duty at the U.S. Naval Nuclear Propulsion Directorate commanded by ADM H. G. Rickover in Washington, DC. Since 1985, he has been a sonar engineer at University of Texas Applied Research Laboratories. His present interests are the introduction of physical principles into signal processing solutions.