1. Advanced Speech Translation Research and Development Promotion Center, National Institute of Information and Communications Technology, Soraku, Kyoto, Japan
2. Department of Information and Computer Science, Keio University, Yokohama, Kanagawa, Japan
3. Chubu Institute for Advanced Studies, Chubu University, Kasugai, Aichi, Japan
4. Department of Computer Science, College of Engineering, Chubu University, Kasugai, Aichi, Japan
5. Department of Robotic Science and Technology, College of Engineering, Chubu University, Kasugai, Aichi, Japan