Finally, I would like to dedicate this thesis to my parents, Maengki Cho and
Sunhee Choung whose warm support and love enabled me to complete this work.
Especially, I would like to give my special thanks to my dad, Maengki Cho. As being a
medical researcher for more than 30 years, my dad has showed me his endless passion
toward learning and research. He is the researcher whom I always want to be. I am very
proud to have a father like him. Thank you and love you.