We bow our heads in most humble thanks to Almighty Allah, the most gracious, the most merciful for granting us the wisdom and strength to complete this work. It is our great pleasure to express our most sincere and deep gratitude to our respected supervisor, Sir Muhammad Habib for his unabated guidance, constant help and encouragement throughout the course of this project. We also wish to express our gratitude and admiration to all the faculty members of air University for their highly useful suggestions and co-operation. We shall be failing in our duty if we do not extend our thanks to our friends and colleagues for their help and encouragement whenever needed. Last but not the least we would like to thank our families for their moral support, love and understanding that enabled us to complete this work