1998.10-1999.10: Visiting professor at the Department of Computer Science, Christian-Albrechts Univ. At Kiel, Germany, carrying out research on robot vision.
1998.8-now: Professor at the Academy of Mathematics and Systems Science, Chinese Academy of Sciences, carrying out research on mathematics mechanization.
1996.8-1998.8: Postdoctoral research associate at the Department of Physics and Astronomy, Arizona State Univ., carrying out research on modeling workstation.
1994.8-1996.8: Postdoctoral researcher at the Institute of Systems Science, Chinese Academy of Sciences, carrying out research on machine proving.