I am profoundly grateful to my thesis examiners, Dr. Joseph Walther and Dr. Jung Younbo. They have given me insightful advice during my confirmation exam period. Furthermore, Dr. Joseph Walther was one of the instructors in the Philosophy of Research class, which helped keep me on the right track of writing and research. Dr. Jung Younbo always supported me, especially when I was using the SONA system for my experiment. Many thanks to my friends, Lin and Guan, for their company and their emotional support; to my fellow graduate students, Yue, Zijian, Yihan, and Kate, for their inputs and thoughtful discussions; and to my lab assistants, Qian, Xishuo, Haitao, and Zhijie, for their efficient work and help. Finally, my deepest appreciation goes to my parents. They respected my choice and provided me with the financial support necessary to pursue my dream. I am grateful for their unconditional love, tolerance, and trust. I hope I won't let them down.