STATEMENT OF AUTHORSHIP

Tóm tắt

I would like to express my deepest appreciation to Assoc.Prof Ph.D. Nguyen Ngoc Vu, who has been the ideal thesis instructor. His sage advice, insightful criticisms, and patient encouragement aided the writing of this thesis in innumerable ways. His guidance helped me in all the time of research and writing of this thesis. I could not have imagined having a better advisor and mentor for my research work. I am also grateful to all my peers who supported me during the course of this research work. Their help, support, and understanding were invaluable to me. Finally, I take this opportunity to express gratitude to all of the Department faculty members for their help and support. I also thank my family for their unending encouragement and support throughout my study. This accomplishment would not have been possible without them. Thank you.