visor, Prof. Bo An. Without the great opportunity he provided, I could not have undertaken this Ph.D. journey, which has been a turning point in my life. During these years, he always maintains a gentle, patient, and kind style. He has not only provided a singularly suitable research environment with the greatest freedom, but also taught me the necessary knowledge in my research life, such as how to be professional and how to properly communicate with others. Words cannot express my gratitude to him. The experience in his group would definitely shape my future in many dimensions. I am so fortunate to become a Ph.D. student under his supervision and I wish to be such a nice professor like him in the future. I also had the pleasure of working with a group of talented people: Qingyu Guo,