부산대학교 도서관

This paper studies the practical learning characteristics of YiJae HwangYoon-seok, a knowledgeable scholar who represented Hunan in the 18th century or so. YiJae met and dscussed with Seo myeng-eung(徐命膺) and Seo Hosu(徐浩修), who were rated as the current practical scholars group, and the designated practical scholars such as Hong Daeyoung(洪大容), Park Ji-won(朴趾源), Park Je-ga(朴齊家), Lee Deokmu(李德懋) to participate in the communication and discussion. He once bought a self-chiming clock, dismantled it and made it again. The standard time used in Joseon dynasty is based on Chinese time, which is not suitable for our country. He argued that our country should set our own standard time.And the importance of national defense. Analysis of advantages and disadvantages of defense according to land and terrain. The importance of cannon and bird cannon, and especially the location and construction of the wall, was revealed. In addition, he was evaluated as a real scholar because of his pursuit of erudition, his characteristics as a real scholar, through the improvement of non-human institutions, and city, geomantic omen, geography and the face reader, through which he could be confirmed as a real scholar again.