1. Knowledge Acquisition & Dialogue Research Team, Guardian Robot Project, RIKEN, Seika-cho, Kyoto, Japan
2. Division of Information Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
3. UPSSITECH, Université Toulouse III - Paul Sabatier, Toulouse, France
4. Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, Japan