First and foremost, I would like to express my sincere appreciation to my supervisor, Associate Professor, Dr. Mahinda Vilathgamuwa, for his invaluable instructions, directions, and consistent encouragement throughout my Ph.D. candidature. I am also deeply thankful to Prof. Choi San Shing, for his knowledge, guidance, fruitful discussions. I am greatly indebted to their broad interests, high enthusiasms for research and exemplary academic standards. Without them, completion of this thesis would have been much more difficult, if not impossible. I am grateful to Nanyang Technological University for providing me research scholarship to carry out this research project. In particular, I would like to acknowledge my gratitude to Mr.Yeoh Tiow Koon, Ms Chew-Sim Annie, and Mr. Lee Ting Yeng for the technical support they have given me in the course of my research. I greatly appreciate Professor, Lalit Kumar Goel, for his concerns and his secretary Koh-Chua Mei Fong, Alice for her continuous consideration. I would also like to thank my friends for their supports in research and personal life. Special thanks to my parents, uncles and aunties for their love, patience and support over these three years or so of my graduate program. Peace soul to my beloved sister. Last but not least, I would like to express my gratitude to my wife, Zhang Jing, for her love, encouragement and understanding.