First and foremost, I am most grateful to my supervisor, Professor , whose useful suggestions, incisive comments and constructive criticism have contributed greatly to the completion of this thesis. She devotes a considerable portion of her time to reading my manuscripts and making suggestions for further revisions. Her
tremendous assistance in developing the framework for analysis and in having gone through the draft versions of this thesis several times as well as her great care in life deserve more thanks than I can find words to express.
I am also greatly indebted to all my teachers who have helped me directly and
indirectly in my studies. Any progress that I have made is the result of their profound concern and selfless devotion. Among them the following require mentioning: Professor , Mr. , and Mr. .
