His research interests include quality of service in mobile and wireless networks, mobility management, mobile ad-hoc networks, and delay/disruption-tolerant networks. He has recently been developing an end-to-end handover method to maintain voice over IP quality, as contributed in Chapter 14. He received his bachelor of management science and his master of business information science from Kobe University of Commerce, Japan in 1999 and 2001, respectively, and his PhD in information science from NAIST in 2003. From January 2004 to February 2005, he was a postdoctoral researcher at Kyushu Institute of Technology, Japan. Since then, he has been a faculty member at NAIST. From February 2010, he has also been a visiting researcher in the Network Research Laboratory of the Computer Science Department, University of California, Los Angeles.