I also would like to extend a special thanks to one of my thesis committees, Dr.
Shelly Rodgers. She showed me her constant enthusiasm for research and strong faith in
my abilities. She was always willing to listen to my ideas and to offer warm suggestion
for improvement. She also has been generously supportive during conducting the
experimental study for the thesis. Her suggestion and advice provide me with many areas
to explore in future research. I also would like to thank other thesis committees who have
encouraged me to do my best during my graduate studies: Dr Paul Bolls and Dr Michael
Kramer. I appreciate all of my committee members for their expertise and commitment.