https://iso26262fs.wordpress.com/2016/05/26/%ec%84%a0%ec%a7%84%ea%b8%b0%ec%97%85%eb%93%a4%ec%9d%98-%ec%9d%b8%ec%9e%ac%ec%9c%a1%ec%84%b1-7%ec%9b%90%ec%b9%99-%eb%84%a4%ec%9d%b4%eb%b2%84-%eb%b8%94%eb%a1%9c%ea%b7%b8/