The completion of my dissertation would not have been possible without the valuable discussions and all the constructive criticism they provided me. In that sense, first, I would like to extend my deepest gratitude to my formal supervisors. Paulo Simões, with his experience and unique way to look at things, always encouraged me on this journey.Invariably, he gave the peace of mind I needed. Then, Edmundo Monteiro whose help and patience cannot be overestimated. In my long journey with ups and downs, whenever I requested, he had a word for me. And last but not least, I would like to express my sincere gratitude to Tiago Cruz. For the careful reader, Tiago does not appear in the first pages as my official supervisor. Nevertheless, after starting this dissertation, I was lucky enough to meet him. Since then, in the last years, I have been working closely with him and we became friends, he was always there to support me and listen to my endless complaints.More, he was kind enough to provide me his expertise and guidance as my supervisor and discuss all the technical details of this dissertation. For all of those reasons, I will always consider him one of my supervisors.Next, without getting into details to avoid being unfair, I would like to thank my friends and colleagues who really worked with me for the past years and made this journey less lonely.We called ourselves the G54 team. This was a group of young and committed researchers who developed strong relationships way beyond the normal working environment. They consistently offered their help, technical support, and push me to complete my dissertation.I'm a proud member of the G54 spirit. Likewise, I would like to extend my sincere thanks to the LCT research group which I'm also proud to be part of. Their continuous support and all the pleasant moments we get together are truly priceless.Finally, I'm deeply indebted to my family, and in particular to my wife, for the full support, motivation, love, and patience.