1. Tohoku University,Research Institute of Electrical Communication,Sendai,Japan
2. University of Aizu,Department of Computer Science and Engineering,Aizuwakamatsu,Japan
3. University at Buffalo, SUNY,Department of Electrial and Electronic Engineering,Buffalo,NY,USA
4. Computer and Electronic Engineering Rensellaer Polytechnic Institute,Department of Electrial,Troy,NY,USA