Professor, Computer Science and Engineering, Korea University (March 2008 ~ ) Director, Center for Engineering and Education of Dependable Software (CEEDS) (July 2009 ~ 2012) Professor, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea (September 1994 ~ Feburary 2008) Director, Defense Software Research Center, KAIST, Daejeon, Korea (March 2006~Feb 2008) Member of Technical Staff, Computer Science Division, The aerospace Corporation, El Segundo, CA, USA (May 1991 ~ September 1996) Member of Technical Staff, Ground System Division, Hughes Aircraft Company, Fullerton, CA, USA (May 1991 ~ September 1996)