Upon the completion of my thesis, I would like to express my deep gratitude to my research supervisors for their patient guidance, enthusiastic encouragement and useful critiques of this research work.
Besides my advisors, I would like to thank the reporters as well as the rest of the jury for their invaluable contribution.
A special thanks to my department’s faculty, staff and fellow students for their valuable assistance whenever needed and for creating a pleasant and creative environment during my studies.
Last but not least, I wish to thank my family and friends for their unconditional support and encouragement all these years.
