MONASH UNIVERSITY THESIS ACCEPTED IN SATISFACTION OF THE REQUIREMENTS FOR THE DEGREE OF I DOCTOR OF PHILOSOPHY i ON -4,9 August 2003 I Sec. Research Graduate School Committee \ Under the Copyright Act 1968, this thesis must be used only under the \ normal conditions of scholarly fair dealing for the purposes of !; research, criticism or review. In particular no results or conclusions [: should be extracted from it, nor should it be copied or closely I paraphrased in whole or in part without the written consent of the [ author. Proper written acknowledgement should be made for any I assistance obtained from this thesis. I J