We study radiative transfer for the analyses of radio and sub-mm wave spectra from molecular clouds and cores, and particularly investigate polarization radiative transfer for the analyses of interstellar medium permeated by magnetic fields. We investigate star formation of molecular cores and structure of late type star envelope using maser radiative transfer of SiO and CH3OH taking the role of magnetic fields into account

We investigate the smallest scale structures and their dynamics with the mm-VLBI observation of the absorption lines of Galactic interstellar medium against very compact AGNs at cosmological distance. We investigate kinematics and origin of high Galactic latitude clouds by combining the absorption line study and conventional emission line observation.

We manage Seoul Radio Astronomy Observatory and develop THz receivers, wideband digital spectrometers/correlators, and related devices. We develop small scale radio interferometer for education and SKA-like dipole array interferometer for the study of solar wind propagation. We develop adaptive optical system to be used with 1 meter class telescope.

We design lightweight space telescopes with Fresnel lens to be working in IR and sub-millimeter range.