**Acknowledgments**

I would like to acknowledge my institution, Bannari Amman Institute of Technology, Sathyamangalam, India, the Honourable Chairman of our institute Dr S V Balasubramaniam, and Our beloved Director Dr S K Sundararaman, who encouraged and provided the necessary facilities to take up this task.

I would also like to acknowledge my mentors, Dr A M Natarajan and Dr A Shanmugam who encouraged me to take up the editorial task of this book. Moreover, I would like to remember their recommendations, when dealing with a difficult problem, revising the very basic ideas and principles, and eventually to try other approaches, even partially or fully innovative. I would also like to express my thanks to the many Professors and colleagues who gave me constructive criticism and useful suggestions. They include: Dr S Selvan, Dr R Harikumar, Dr S Ramakrishnan, Dr Amitabh Wahi, Mr T Vijayakumar and Others.
