Without their support I would not have been able to finish this eventful and rewarding journey. Your belief in me, support, humor, and positiveness kept me going through the path until the end. This dissertation is dedicated for you. Above all, I would like to thank my academic advisor Panos K. Chrysanthis for his admirable guidance and support during my PhD years. His incremental step-wise research style, holistic view of research problems, and story telling talent have shaped me to be the scientific researcher I am. I also would like to thank Constantinos Costa for his technical support, dedication to shape this work, and high availability for feedback. I would like to thank the rest of the committee members for their valuable feedback and support. I would like also to thank my colleagues and co-authors of several papers Daniel Mossé and Daniel Petrov. Working with you has been a pleasure and a very rewarding experience. Moreover, I would like to extend my gratitude to the rest of the Advanced Data Management Technologies Lab members and my colleagues and friends at PITT that I have known during this journey, for you have been available for feedback and personal support when I needed