Acknowledgements
Foremost, I would like to express my sincere gratitude to my advisor Dr. Xuelin
Huang for his continuous support of my Ph.D study and research, for his patience,
motivation, enthusiasm, and immense knowledge. His guidance helped me at all times
in the research and writing of this thesis. I could not have imagined having a better
advisor and mentor for my Ph.D study.
Besides my advisor, I would like to thank the rest of my thesis committee: Dr.
Dennis D. Cox, Dr. James R. Thompson and Dr. Wotao Yin, for their encouragement,
insightful comments, and questions.
My sincere thanks also goes to my husband, Shu Han, my parents, Guohua Zhang
and Xinhua Wang, and my sister, Yi Zhang for their everlasting encouragement and
support.
I thank my fellow classmates Hongxiao Zhu, Xiaowei Wu, and Bo Peng, and my
colleague Erin English. They all offered sincere help on my thesis.