1. Department of Information Science, University Arkansas, Little Rock, AR 72204-1099, USA
2. Teknoset Research, TUBITAK MAM, Gebze 41730, Turkey
3. Mitsubishi Electric Research Labs, 201 Broadway Avenue, Cambridge, MA 02139, USA
4. Computer Science and Engineering Department, School of Engineering Arizona State University Tempe, Arizona State University, Tempe, Arizona 85287, USA