[1] Illinois Wesleyan Univ, Dept Math & Comp Sci, Comp Sci, Bloomington, IL 61761 USA
[2] West Virginia Univ, Concurrent Engn Res Ctr, Lane Dept Comp Sci & Elect Engn, SIPLab,Comp Sci, Morgantown, WV 26506 USA
[3] West Virginia Univ, Concurrent Engn Res Ctr, Lane Dept Comp Sci & Elect Engn, SIPLab, Morgantown, WV 26506 USA
[4] West Virginia Univ, Concurrent Engn Res Ctr, Lane Dept Comp Sci & Elect Engn, SIPLab,Comp Sci & Elect Engn, Morgantown, WV 26506 USA
[5] Jilin Univ, Coll Comp Sci & Technol, Changchun 130012, Jilin, Peoples R China