[ ] .29 , 172 IT 3 . . , . , . ., . . 2016 7 , 112 . . IT (Zaryab Khan) 10+ Z2, S20 . . 5% 40 . 2016 7 . , . , . 2017 1 7 ' '(root cause) " huimin0217@seoul.co.kr [ ] ... 6m 6 , 3 (nowne… [+30 chars]