This author has not been identified. Look up 'Hiroki Okada' in GoogleThis author has not been identified. Look up 'Atsushi Takayasu' in GoogleThis author has not been identified. Look up 'Kazuhide Fukushima' in GoogleThis author has not been identified. It may be one of the following persons: Look up 'Shinsaku Kiyomoto' in GoogleThis author has not been identified. Look up 'Tsuyoshi Takagi' in Google