3 Preface

This thesis is the final step in completing the Master Economics & Informatics at Erasmus University Rotterdam. It took me longer than expected, but I am glad that after years of work, this thesis got to an end. Many people encouraged and supported me in this period and I would like to thank them for their support. First of all, I would like to thank my first supervisor Martins Smits for his advice, critical comments and patience. After all those years, with its up and downs, he kept supporting me. Without his support and patience, this thesis would never have come to an end. Furthermore, I would like to thank my second supervisor Gert van der Pijl for his time and advice, but also for making it possible to write this thesis under his and mister Smits his supervision. Last but not least, I would like to thank my parents for both enabling and stimulating my education and the rest of my family and friends for their sincere support