\title{Acknowledgements}
This thesis and the research it presents is not the result of just my own
work. I have received a lot of ideas, inspiration and comments from other
people, who I would like to mention here.

First of all, I would like to thank Christiaan Baaij, which has been my
partner in crime during this research. Together we have started a new area of
research at the University of Twente, in which I would not have progressed so
far on my own.

Then there is my first supervisor, Jan Kuper, whose visions and ideas have
sparked this research and who always managed to place my practical views into
the proper theoretical background. The rest of the graduation committee has
been a great help, providing feedback, comments and challenging questions,
each from their own unique point of view.

Finally, I would like to thank Brenda, who has been suffering my working
late and general lack of time for just over a year now.
