- Professor, Dept. of Industrial & Management Engineering, Hankuk University of Foreign Studies
- Research Staff Member, IBM Research – Ireland, Smart City Research Center, 6/2013 – 2/2015
- Senior Researcher, Electronics and Telecommunications Research Institute (ETRI), 7/2011 – 6/2013
- Invited Professor, Korea Advanced Institute of Science and Technology, 12/2010 – 6/2011
- Visiting Scholar, Rutgers University, New Jersey, United States, Research optimization theory and applications, 2009–2010.
- SW development team manager, Intellicube, Seoul, Korea, Developing logistics optimization package, 2002–2004.
- SW development team manager, Koino, Daejon, Korea, Developing internet based collaboration system, 2000–2002.