by jian chen. thesis (m.s.)--university of south florida, 1993. includes bibliographical references (leaves 103-106). electronic reproduction. [florida] : state university system of florida, palmm project, 2001. (florida heritage collection) mode of access: world wide web. system requirements: internet connectivity; web browser software; adobe acrobat reader to view and print pdf files. electronically reproduced by the university of south florida from a thesis in the main library at the university of south florida, tampa.