a researcher. Dr. Jianfei also provided much guidance when I was confused about experiment results as well as my research direction. Finally, as a self-funded M.Eng. student, I want to express my greatest gratitude to my parents, who funded me throughout my M.Eng. candidature. They also provided me with comfort when I was facing difficulties. Overall, I am thankful to people who had helped me along the way and I simply cannot express my gratitude enough for them. ix