First, I thank and I'm grateful for Allah for taking care of me and protecting me all the time. I would Thanks everyone who helped me in reaching this stage My Father and My Mother thank you for everything you have done to me my entire life My supervisor Dr. Tawfiq S. Barhoom for his encouragement and support, without his effort I couldn't finish my thesis, My Brothers (Hossam, Mohanned) & my sisters (Rana, Haneen, Randa) for their love I would like to express my appreciation to the academic staff of information technology program at the Islamic University-Gaza.