This research is partially supported by ARO DAAL03-89-C-0031 including U.S. Army Research Laboratory (Aberdeen); U.S. Air Force DEPTH through Hughes Missile Systems F33615-91-C-0001; Naval Training Systems Center N61339-93-M-0843; Sandia Labs AG-6076; DMSO through the University of Iowa; NASA KSC NAG10-0122; MOCO, Inc.; National Library of Medicine N01LM-43551; NSF IRI91-17110, CISE CDA88-22719, and Instrumentation and Laboratory Improvement Program #USE-9152503.