**Acknowledgements**

Firstly, I would like to express my sincere and heartfelt gratitude to my supervisor Prof. Wilson Jeberson, Department of Computer Science and Information Technology, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, for his impetus observation and stimulating questions on my research experiments. His deep thoughts and discussions that followed with it gave me an insight into the development of my work. The meetings and conversations were vital in inspiring me to think outside the box, from multiple perspectives to form a comprehensive and objective critique.

Further, I feel a deep gratitude for Prof. Jeberson for his uninterrupted assistance of my PhD study and affiliated research, for his forbearance, inspiration, and great awareness. His support helped me throughout my research and in writing this thesis. I could not have visualized a better advisor and mentor for my PhD study.

I am grateful to my fellow researchers for the stimulating discussions, for the sleepless nights we were working together before deadlines, and for all the fun we have had in the last 4 years. Also, I thank my friends in the Department of Computer Science and Information Technology, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj.

Last but not the least, I would like to thank God, my family: my parents and to my brothers and sister for supporting me spiritually throughout writing this thesis and life in general.
