Michele Mae Covell.Also issued as Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.Includes bibliographical references (p. 253-256).Supported in part by the Defense Advanced Research Projects Agency and monitored by the Office of Naval Research. N00014-89-J-1489 Supported in part by the National Science Foundation. MIP 87-14969 Supported in part by Sanders Associates, Incorporated.