[1] Brendan Iribe Ctr Comp Sci & Engn, Ctr Comp Sci & Engn, Dept Comp Sci, 8125 Paint Branch Dr, College Pk, MD 20742 USA
[2] Microsoft Corp, One Microsoft Way, Redmond, WA 98052 USA
[3] Univ Calif Berkeley, Dept Elect Engn & Comp Sci, 506 Cory Hall, Berkeley, CA 94720 USA