Pennsylvania State University
USA
Pennsylvania State University, University Park, PA
Dept. of Comp. Sci. and Eng., The Penn. Ste. Univ., Univ. Park, PA 16802-6106, USA (Correspd. 342 IST Building, Dept. of Comp. Sci. and Eng., Univ. Pk., PA 16802-6106, USA. Tel.: +1 814 863 3646; Fax: +1 814 865 3176; byang@cse.psu.edu)