ACKNOWLEDGMENTS

 I would like to thank my advisor, Dr. Principe, for providing me with the

opportunity to work on such a wide and challenging subject. He allowed me a great

freedom to experiment and find my own way, while at the same time giving me valuable

insights and supervision. I am grateful to Dr. Harris for being the inspiring teacher who

awakened my motivation and interest for signal processing at my arrival in the graduate

program; and to Dr. van Oostrom for his availability and patience during the past few

months.

 Special thanks go to my family back home and all my friends, who always

supported and strengthened me, and to the best roommate ever this side of the Atlantic.