I would like to express my sincere gratitude to my supervisor, Professor Koh Soo Ngee, and my co-supervisor, Associate Professor Rahardja Susanto, for their invaluable guidance and pertinent advices during my study. Moreover, I would like to thank their constant encouragement, their enormous time and effort that they have made pertaining to this research and thesis writing. I am deeply grateful to my parents, Mr. You Bao Hui and Ms. Zheng Hui Yu, and my wife, Jiang Ping, and my two sons, Li Ming and Li Hong, for their endless love, support and encouragement. I would also like to thank my final year project students from National University of Singapore, Ms. Chen Kexin, Mr. Tan Chun Wee and Ms. Sem Pak Ling, for sharing with me their projects and many interesting and helpful discussions.