1. Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI 48202 USA (e-mail: syxie@wayne.edu)
2. Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI 48202 USA.
3. Department of Mathematics, University of Connecticut, Storrs, CT 06269 USA.
4. Division of Engineering Technology, Wayne State University, Detroit, MI 48202 USA.