1. Department of Computer Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 1698555 Japan
2. Osaka Institute of Technology, 1-79-1 Kitayama, Hirakata City, Osaka, 5730196 Japan
3. e-Seikatsu Co., Ltd., 5-2-32 Minamiazabu, Minato-ku, Tokyo, 1060047 Japan