Add to ORKGThis short passage is dedicated to many people, to whom I would like to express my sincerest appreciation for their kind support throughout my doctoral program. I am deeply indebted to my adviser Paul Glewwe for his advice, mentorship, and en-couragement. He was not only a valuable thesis adviser, but also a supervisor for my research assistantship. Paul spent a large amount of time discussing this thesis as well as other research projects. Without his valuable advice and guidance, this thesis would not be accomplished. I would like to thank Roger Feldman, Terry Roe, and Baolin Wu for serving in my committee and their helpful comments on this paper. Numerous professors provided helpful comments and suggestions at various stages of my disser...