Acknowledgments

My sincere thanks to my supervisor Professor Gustavo de Veciana for his tremendous efforts on my behalf over the five years that we have worked together. What I have learnt in these five years is not only how to do pure research, but also being a confident speaker, a rigorous researcher, a responsible instructor, a good collaborator and much more. I would also thank Professors Andrews, Baldick, Shakkottai and Vin for participating my Ph.D. committee and providing me many valuable suggestions and directions on my research. I must particularly thank Professor Andrews and, my former colleague, Professor Weber for their collaboration and contributions to my work. I would not have been able to work on so many interesting problems without them. I also would like to thank my friends Jay, Xun, Jangwon, Seungjun, Alex, Shailesh and Balaji for making a friendly, open minded and creative research group to work in. I also want to thank my former supervising Professors Yujin Zhang, Qingmin Liao and Xinggang Lin, from whom I learnt elements of serious and rigorous research. My special thanks go to Mr. and Mrs. Chujo, Mr. Takeo, Chingfong, Hungying and Richard at Fujitsu Labs of America for their tutoring and collaboration when I was inter