Here I express my deep appreciations to my supervisor Assoc Prof. Lim Meng Hiot for suggesting this promising research area, his valuable guidance, constructive suggestions, helpful criticism during the whole period of my research. His concerns on my life, on my research progress and on my course work kept pushing me closer and closer to my objective. His supervision built me up in almost all aspects including research attitude, research philosophy, English, Copyright, living attitude and so on. All these will help me very much in my onward whole life.