Chong Long
Ph.D Candidate
Department of Computer Science and Technology,
State Key Laboratory of Intelligent Technology and Systems,
Tsinghua University, Beijing 100084, China
Email: longc05@mails.tsinghua.edu.cn
(Now I am visiting
David R. Cheriton School of Computer Science,
University of Waterloo, Waterloo, Ontario N2L 3G1, Canada)