He has not been seen in public since October 2014, when he and six other officials disappeared in a purge connected to Supreme Leader Kim Jong Un.

[1] He studied at the Faculty of Automation at Kim Il Sung University in Pyongyang between September 1982 and August 1987, where he received his Master of Engineering.

In that office, one of his main roles was overseeing the North Korean mobile phone network, Koryolink.

[4][5] On 23 October 2014, a source told the South Korean newspaper JoongAng Ilbo that they had received "reliable information" that six minister-level officials had been purged from the government and executed.

[citation needed] Sim did not appear often in state media, but his absence from a meeting of North Korean officials with Naguib Sawiris, head of the Egyptian company Orascom Telecom, which provides North Korea's mobile network, was considered unusual.