Department of Computer Science, Pacific Lutheran University, Tacoma, WA, 98447, USA.|Department of Electrical Engineering and Computer Science, Wichita State University, Wichita, KS, 67260, USA.|Department of Computer Science, University of Missouri, Columbia, MO, 65211, USA.|Department of Computer Science, University of Missouri, Columbia, MO, 65211, USA. chengji@missouri.edu.