Cory S. Myers.Originally presented as author's thesis (Ph. D.--Massachusetts Institute of Technology), 1986.Bibliography: leaves 232-235.Supported in part by the Advanced Research Projects Agency monitored by ONR under contract no. N00014-81-K-0742 Supported in part by the National Science Foundation under grant ECS-8407285 Supported in part by Sanders Associates, Inc and an Amoco Foundation Fellowship.