출처 : http://cihe.skku.edu/download/%EB%85%B8%EA%B7%9C%EC%84%B1_%EA%B5%90%EC%88%98_DL_6,_%EB%B9%85%EB%8D%B0%EC%9D%B4%ED%84%B0%EC%99%80_%EB%8D%B0%EC%9D%B4%ED%84%B0%EC%82%AC%EC%9D%B4%EC%96%B8%ED%8B%B0%EC%8A%A4%ED%8A%B8%EC%9D%98_%EB%AF%B8%EB%9E%98,_2014_12_19.pdf
