First and foremost, I would like to thank my advisor, Dr. Richard W. Conners, for his immeasurable guidance, patience, and support throughout the course of my Master and Ph.D. studies. I have learned much as a direct result of working with him. In addition, his confidence in my capability has enabled much of my creative work as well as diligent working habits.
I would also like to thank Dr. A. Lynn Abbott, Dr. D. Earl Kline, Dr. James R. Armstrong, Dr. Scott F. Midkiff, and Dr. Jeffrey H. Reed for their helpful advice and for being on my committee. Financial support during my studies was mainly provided by Federal Aviation Administration and is greatly appreciated. Warm thanks to Dr. Thomas H. Drayer, Yuhua Cui, Shubing Zou, Xinhua Shi, Panos J. Arvanitis, Nanpeng Chen, Wei Xie, Paul Lacasse, Hongliang Wu, Jinhuo Shan, and all the people who have worked with me on the project at the Spatial Data Analysis Laboratory. I would like to thank Jun Xu, and all my other friends in Blacksburg for their friendship and support during my Ph.D. studies. I express my special gratitude to Dr. Shiu Cheung at the FAA Research Center for providing invaluable support.
Special thanks to my parents Zuyin Lu and Runsheng Zhu for their high standard on my academic career and strict discipline on my early education. My father, who passed away several years ago, still has deep influences in every aspect of my academic career and my life. I also dedicate this dissertation to my sister Dr. Bin Lu and my brother Dr. Feng Lu for their support and understanding.