First and foremost, I would express my deep gratitude to my supervisor, Associate Professor Tan Ah Hwee, for his trust, support, encouragement and guidance in my research. His patience and understanding coupled with his research and teaching experience has immensely contributed to my knowledge and research ability. I really appreciate him not only for his advice in my research but also instructions and help for my life. I would like to thank Mr. Wang Di, Miss. Wang Wenwen, and Dr. Budhitama Subagdja for their valuable help during my research. I also thank my lab-mates in Centre for Computational Intelligence Laboratory for their kindly help and assistant. Moreover, I want to thank all my friends. Their encouragement and comfort make me brave, especially when I face difficulties. Last but not least, I deeply appreciate my parents, my husband Hui for their selfless giving, support and love. Thank you.