I, hereby, gratefully acknowledge all the people who were involved in my esteemed journey of this doctoral study. Without their support, time and efforts, this journey would not have been completed. But before this, I would like take this moment to congratulate my supervisor Dr. Helga Dorner, a director of Institute of Research on Adult Education and Knowledge Management at the Faculty of Education and Psychology, Eötvös Loránd University. We started the journey together, we went through the journey together and we are now here together. Therefore, it would be more correct to congratulate her. She has been an excellent professional who tremendously helped, inspired and encouraged me throughout the entire journey. She has been an admirable professional who has competently mastered her daunting task as a supervisor along with many other important responsibilities of hers. She has been always present and available to me. She has been very patient with me. She has nurtured me. She is my role model and I want to be a supervisor, a researcher and a professional like her. I am very fortunate to have met her as my supervisor, who guided me confidently and competently throughout the challenging and adventurous journey and who opened the prestigious door of a scientific community for me. I am forever indebted to her and I will not forget this. Congratulations, Dr. Helga Dorner, my supervisor! First and foremost, I would like to express my immense gratitude to the Hungarian Government and the Hungarian People from the bottom of my heart. With the full support of Stipendium Hungaricum Scholarship Programme, I have completed this long journey without struggles. It would be impossible for me to study at this surprisingly good university, Eötvös Loránd University, and admiringly wonderful country, Hungary, without this utmost chance. I am deeply honoured to be a part of this great programme and it would absolutely be one of unforgettable and precious memories of my life. I deeply appreciate the Tempus Public Foundation and its staff for their efforts to manage and support my study here in Hungary. My heartfelt gratitude goes to the distinguished reviewers, Dr. Zsuzsa Kovács, Eötvös Loránd University, and Dr. habil. Balázs Németh, Pecs University. I really appreciate Dr. Zsuzsa Kovács for her valuable time. She was one of the reviewers of this research when it was proposed and she can now see how her feedback then had an impact on the research work. I greatly appreciate for her attentive reading of the entire research work and for her very specific questions and recommendations, which have made it so clear to us what we need to modify. And her reflections on the research work were very inspiring and motivated us well enough to revise it. I truly appreciate Dr. habil. Balázs Németh for his kind acceptance as an external reviewer and his valuable time for reviewing the research work. His recommendations on the relevant sources and in-depth and far-reaching questions guided us well in improving the research work, and, most importan...