He received his B.Eng., M.Eng., and Ph.D. degrees from Kyoto University in 1994, 1996, and 2002, respectively. He was a research fellow of the Japan Society for the Promotion of Science from 2001 to 2002. He was an assistant professor in the Graduate School of Informatics at Kyoto University from 2002 to 2009. He was a visiting assistant professor in the Department of Computer Science at Stanford University from 2003 to 2004. His research interests include machine learning, data mining, information retrieval, crowdsourcing, and human computation.