I would like to express my deepest appreciation to Professor Hiroshi Ishiguro. Without his kind supports, my research life in Japan would not be possible.

And I would like to express my sincere gratitude to Professor Carlos Toshinori Ishi, Associate Professor Yuichiro Yoshikawa, Dr.Takashi Minato, and Dr. Chaoran Liu for leading me into the world of robotics, speech technology, and artificial intelligence.