https://blog.faceutil.com/2017/05/06/2010%eb%85%84%ec%9e%91-%ec%bd%94%eb%82%9c-14%ea%b8%b0-%ea%b7%b9%ec%9e%a5%ed%8c%90-%ec%b2%9c%ea%b3%b5%ec%9d%98-%eb%82%9c%ed%8c%8c%ec%84%a0-%ec%9e%90%eb%a7%89-smi-%e3%8e%a3/