First, I would like to thank my advisor Dr. Antônio Nélson Rodrigues da Silva for continuously supporting me in my PhD study. I appreciate all his contributions in terms of time, ideas and funding to complete my PhD. His guidance, supervision and collaboration helped me throughout the research and writing up of this thesis. The sense of responsibility, tireless work and enthusiasm he has for teaching his students was contagious and motivating. For me, he is an example of an excellent educator, researcher and human being. Besides my advisor, I would also like to thank Dr. Peter Zeile for the guidance and support during my internship in Karlsruhe. His teachings, collaboration and friendship were essential for this study. In addition, I would like to thank the research group at the Karlsruhe Institute of Technology (KIT), Professors Markus Neppl, Robert van Gool, Angelika Jäkel and secretary Maria Schweitzer for the support during my internship. I would also like to thank my friend, Carolin Mack for making my stay in Germany more enjoyable.