[4/2015-] Research Scientist, Department of Industrial and Systems Engineering, Chuo University.

[4/2012-3/2014] Research Member, “Advanced Computing & Optimization Infrastructure for Extremely Large-Scale Graphs on Post Peta-Scale Supercomputers” Project, CREST, Japan Society and Technology Agency.

[4/2012-] Professor Emeritus, Dept. of Mathematical and Computing Sciences, TokyoInstitute of Technology.

[7/1994-3/2012] Professor of Dept. of Mathematical and Computing Sciences, Tokyo Institute of Technology.

[12/1989-6/1994] Professor of Dept. of Information Sciences, Tokyo Institute of Technology.

[4/1979-11/1989] Associate Professor of Dept. of Information Sciences, Tokyo Institute of Technology.

[4/1975-3/1979] Assistant Professor of Dept. of Information Sciences, Tokyo Institute of Technology.

[4/1973-3/1975] Assistant Professor of Dept. of Administrative Engineering, Keio University, Yokohama, Japan.