for their help and encouragement. I would also like to say that I was very lucky to be supervised by Prof. Steve Hurley as he is a very special person, he has been my inspiration over the course of this work, and I would like to thank him for his great patience, enormous support in all aspects, for having faith in me and keeping me positive all the way. I would like to thank the best Mum in the world, who made this all possible and gave me wings when I needed it most.