Firstly, I would like to express my deepest gratitude to my advisor Dr. Lam Siew-Kei for his patience and continuous support during my doctoral thesis. All through my PhD, he has guided me at each step from delving deeper into technical issues, providing a high-level view of my research, to editing my manuscripts. My thesis would not have been the same without his supervision.Besides my advisor, I would like to sincerely thank Rohan Juneja, who has helped me to construct the way of my work and research efficiently. I would also like to express gratitude to Dr. Guiyuan Jiang for his continuous advice.Next, I would like to thank my friends at NTU -Nimisha, Kratika, and Tushar, who have always provided me guidance and helped me through all hurdles.Finally, I would like to thank my family: my grandparents, parents, and sister. They have always encouraged me and stood by me in whatever I pursue. Their affection and support for me, during my PhD and even otherwise in my life, is immeasurable. Special thanks to Vardhman, and Prerna, who have been like family to me these past four years in Singapore and have made this journey immensely memorable.