https://guide.jinbo.net/workplacesurveillance/4%ec%9e%a5-%ea%b0%90%ec%8b%9c%ec%84%a4%eb%b9%84-%eb%8f%84%ec%9e%85%ec%97%90-%eb%8c%80%ed%95%9c-%eb%8c%80%ec%9d%91-%eb%b0%a9%ec%95%88/6-%ec%a7%80%eb%ac%b8-%eb%93%b1-%ec%83%9d%ec%b2%b4%ec%9d%b8%ec%8b%9d%ec%a0%95%eb%b3%b4%ec%9d%98-%ec%88%98%ec%a7%91/