Content

I would like to take this opportunity to thank my dear parents, Bo and Barbro. Without their warm support in numerous ways, it would definitely have been more burdensome to write this thesis. By supplying me with computers since my early teens, they undoubtedly awakened my interest for computers. I owe my parents everything. I would also like to thank Cristina Landgren for patiently listening to my tedious monologues regarding the issues in this thesis and for giving valuable advice. I am also very grateful to Professor Lennart Svensäter, who believed in this subject and agreed to le