Since its construction in the late 14th century, Hanyangdoseong had been carried out three major repairs and reconstructions during the 500 years of the Joseon Dynasty. In addition to the large-scale construction, small-scale construction continued until King Gojong era. In particular, in the 18th century, systematic construction management was implemented by the craftsmen and the military participated in the renovation of Hanyangdoseong in earnest, and the construction methods also developed rapidly. In the early 18th century, new construction techniques were attempted in various sections of the reconstruction work, and gradually became a common technology for repairing Hanyangdoseong in the late 18th century. The purpose of this study is to examine the characteristics and period of changes in the 18th century's construction technique, when the rapid development of Hanyangdoseong took place. To this end, the excavation results related to Hanyangdoseong, the remaining city wall, and the inscribed stones were used to identify and demonstrate the characteristics and change of the construction method.

This paper sought to examine characteristics and differences of the construction methods and the materials of the wall repair by three command through individual command records and national documents. This paper is based on the management section of three commands(Samgunyoung), which was in charge of a repair and management of Hanyangdoseong(Seoul city wall) in 18th century. The purpose and background of the study are as follows. First, through each inscribed stones on the rampart and the parapet, it is to grasp accurately the point of change of Hanyangdoseng after the 18th century. Second, through inscribed stones, the site evidence of the repair work in the late Joseon Dynasty, it is to find out the aspects of the development process of repair and reconstruction technology of Hanyangdoseng.

The main objective of this work is to perform experimental analyses of a absorption refrigeration system using a new refrigerant-sorbent pair as the working pair. The active component of sorbent is sodium thiocyanate (NaSCN). Ammonia (NH3) is chosen as refrigerant. As a result of these, it is concluded that the unit exhibits good cooling performance and the average cooling capacity is approximately 28.8kW and the average coefficient of performance (COP) of absorption system is 0.56. The unit is a thermal compressor which uses low-grade waste heat to generate refrigeration (cooling or freezing).