E. Weinstein, A.V. Oppenheim and M. Feder.Includes bibliographical references (leaf 38).Research supported by in part by the Defense Advanced Research Projects Agency and monitored by the Office of Naval Research. N00014-89-J-1489 Research supported in part by Lockheed/Sanders, Inc. Research supported in part by the Office of Naval Research. N00014-90-J-1109