[1] Chinese Univ Hong Kong, Shatin, Hong Kong, Peoples R China
[2] Penn State Univ, University Pk, PA 16803 USA
[3] Georgia Inst Technol, Atlanta, GA 30332 USA
[4] Univ Calif Berkeley, Berkeley, CA 94720 USA
[5] Hong Kong Univ Sci & Technol, Kowloon, Hong Kong, Peoples R China