The success of this thesis can be succeeded by the attentive support from my advisor, Lecturer, Dr. Suwisa Mahasadana for her knowledge and her logical way of thinking have been of great value for me. Her understanding, encouraging and personal guidance have provided a good basis for the present thesis. I really appreciate the assistance I have received from Associate Professor Dr. Preayoon Fongsatitkul, my co-advisor for his valuable advices and providing suggestions for improvement.