Bahram Shafai. I am deeply indebted to him not only for his fundamental role in my doctoral work, but also for every bit of guidance, expertise, and assistance that he selflessly provided. He gave me the freedom to examine a wider scope of research interests and contributed with most vital feedback, insights, and encouragements. I especially benefited from his expertise and knowledge to explore new directions and solve challenging problems. During the most difficult times of writing this dissertation, he gave me the moral support and the freedom I needed to make progress. It has been an honor to be his Ph.D. student. I gratefully acknowledge the members of my Ph.D. committee, Professor Mario Sznaier, Professor Rifat Sipahi, and Professor Mikhail Malioutov for their time and valuable feedback on preliminary version of this dissertation. I also highly appreciate their flexibility in dedicating their precious time for serving in my Ph.D. committee. I can never find enough words to describe how grateful I am for all of the supports my family provided for me in every part of my life. I am deeply thankful to my father for his support and guidance throughout my entire life. I am also grateful to my beloved mother whose emotional support and encouragements cherished me all these years. I also like to thank my sister for her love, encouragement, and empathy. Finally, my utmost love and appreciation goes to my dear wife, Shima,