Affiliation: | (1) Research Institute of Electrical Communication, Tohoku University, 2-1-1 katahira, Aoba-ku, Sendai Miyagi, 980-8577, Japan;(2) Depertment of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580, Japan;(3) JST-CREST, 3-5 Chiyoda-ku, Tokyo 102-0075, Japan; |