OF THE UNIVERSITY OF MINNESOTA BY

iAcknowledgments First, I thank God for health, strength, and guidance he provides in everything I do. In my graduate studies I have benefited from interactions with many individuals some of whom I will acknowledge by names. I am grateful to Professor G. B. Giannakis who served as my academic advisor during my doctoral studies. His energy, enthusiasm, and frankness have helped me grow as a researcher. Collaboration with Prof. Giannakis has given me a lasting impression on the virtues of rigor and attention to detail in academic enquiry. I am grateful for the generous amount of time he invested in my training and for his patience with my shortcomings. I am thankful to Profs. Stergios Roumeliotis, Tryphon Georgiou, and Mostafa Kaveh for agreeing to serve on my PhD final examination committee. Research collaborators during my doctoral studies, including Profs. Stergios Roumeliotis and Alejandro Ribeiro, with whom I have had exciting and fruitful exchange of ideas, are gratefully acknowledged. Further gratitude is due to the graduate students and visitor