\chapter{Acknowledgements} \label{ch:ack} Upon the completion of my thesis, I would like to express my deep gratitude to Prof. Dimitris Kotzinos for believing in me and for providing me with opportunities that helped me pave my path in academia. This thesis would not have been possible without the patient guidance of Prof. Katerina Tzompanaki. Her love for learning and hard work were inspiring and served as the catalyst for every single step that I made towards getting a better grasp on computer science. I am genuinely grateful to the reporters for their time, effort, and valuable feedback. A special thanks goes to Alexandros Kontarinis for being an exemplary colleague and a unique companion during this journey. I would also like to thank the department's faculty, the lab's staff and researchers for creating a pleasant and creative environment. Last but not least, I wish to express my thankfulness to my family and friends for their unconditional support and encouragement all these years. \bigskip \noindent Cergy-Pontoise, \thedate