I would like to express my gratitude to my supervisor, Dr. Chia Liang-Tien, for his advice and support throughout the whole process of my Ph.D study. I am sincerely grateful for his guidance, understanding and patience in leading me through this effort. My research could not have been finished without insightful advice from him. I would like to extend my thanks to Dr. Deepu Rajan and Dr. Manoranjan Dash for their thorough help and supervision. They kindly assisted me in many aspects. I also would like to thank all my colleagues in Center for Multimedia and Network Technology (CeMNet), for their understanding and supports. In particular, I'd like to thank