by Petros Kapasouris, Michael Athans, Gunter Stein.Caption title. "Prepared for 27th IEEE Conference on Decision and Control--Austin, Texas--December 7-9, 1988." "TP-291."Includes bibliographical references.Support provided by the General Electric Corporate Research and Development Center. Support provided by the NASA Ames and Langley Research Centers. NAS/NAG 2-297