4 years of PhD study was a long journey which I could not have finished without the support of a large number of unbelievable people. With great pleasure and great sense of satisfaction, I take this opportunity to express my sincere thanks to my supervisor Assoc. Prof. Lee Pooi See, for her invaluable guidance and constant encouragement at each and every step of my PhD research. I would like to show my sincere appreciation for her great support, vision, and patient instruction.