1. The Department of Electrical and Computer Engineering; The University of Texas at Austin; TX; 78712-0240; USA
2. Department of Computer Science; Gyeongsang National University; Gyeongsangnam-Do; Korea
3. The Division of Engineering and Applied Sciences; Harvard University; Cambridge; MA; 02138; USA
4. The Department of Information and Communication Engineering; Myongji University; Yongin; Korea