The combinatorics, matrix theory and the combinatorial
matrix theory which occurs from combinatorics and matrix
via the symbiotic relation between those two theories.
Special interest is on the optimization of combinatorial
matrix functions and (0,1)-matrices associated with graphs,
which have profound of applications in the area of computer
science, information technology and sociology etc.

1977~Present Professor (currently), Kyungpook National
University
1990 Professor, Sung Kyun Kwan University
1996 Vice Dean of the Planning Office, Kyungpook
National University
1997 Vice Dean of the Office of Academic Affairs,
Kyungpook National University
1998 Director of the Science Education Center for
Gifted Youth, Kyungpook National University
1999 Director of the Topology and Geometry Research
Center, Kyungpook National University
2000 Chairman of the Problem Selection Committee, the
41st International mathematical Olympiad
2001 Director of the Science Education Reasearch Institute,
Kyungpook National University
2001 Visiting Research Professor, Univ. of Wyoming

1999 Korean Mathematical Society Academic Award
2001 Award for devotion to the Science and Technology
(Prime Minister Award)