I would like to express my deepest and truthful gratitude and respect to my advisors Prof. V.J.T. Raju and Dr. Yonas Chebude for their significant observations and direction, invaluable advice and guidance, continuous supervision and encouragement, assistance and support that greatly encouraged me to accomplish this project work. "Never reject anybody in your life, because good people give us happiness and bad people give us experience. Both are essential in life." “Never ignore a person that loves you, cares for you, and misses you. Because one day, you might wake up from your sleep and realize that you lost the moon while counting stars” Peace of God be with all of you wherever you are on this planet.