[1] Sogang Univ, Dept Comp Sci & Engn, Seoul 121742, South Korea
[2] Univ Maryland, Robert H Smith Sch Business, College Pk, MD 20742 USA
[3] Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA
[4] Univ Maryland, Dept Elect & Comp Engn, College Pk, MD 20742 USA