Acknowledgements

I firstly wish to thank Les Little for his help in producing the ASTRA program, in particular during the rather long and drawn out debugging period. I would also like to thank him for the considerable effort he put into proof-reading this thesis and the innumerable suggestions he made that have made this a better piece of work than it would otherwise have been.

I thank Andy, Brian, Duncan, Keith, Mark, Mark and Maria for making working in the lab such fun.

No acknowledgement would be complete without mentioning my dearest wife, Barbara, who has been my constant supporter for the last 5 years.

Equally this acknowledgment would would not be complete without thanking my parents for their continuous support throughout my 7 years as a student, specifically including the donation of the odd penny or two to my hardship fund.

Finally, last but by no means least to Linus, who despite doing his best to prevent me from ever finishing this thesis, has made the last 7 months the most fulfilling of my life.