Competition

ACKNOWLEDGEMENTS During the preparation of this thesis, there have been many people whose prayer, support, and encouragement have contributed to its accomplishment. First of all, I would like to thank my advisor, Professor Shijie Deng. His thoughtful comments, helpful suggestions, and consistent guidance made the preparation of this thesis an invaluable experience. My sincere thanks go to Professor Robert P. Kerts. His kind suggestions and valuable comments contributed to this thesis in many ways. I would like to thank Professors Paul M. Griffin and Joel Sokol, and Dr. Qiong Wang for their much appreciated opinions and service on my thesis committee. I also wish to acknowledge financial support by the School of Industrial and Systems Engineering of the Georgia Institute of Technology. I owe many thanks to my friends in South Korea and Atlanta for their friendship, prayers, and encouragement during my study. Finally, I dedicate all my work to my parents, brothers, sisters, and my husband. Their presence has always been my strength