This study analyzes the characteristics of the Angbu-ilgu, a Korean sundial resembling a concave hemisphere, which was crafted in 1434 during the sixteenth reign of King Sejong (r. 1418–1450) of the Joseon Dynasty, although no remains of it exist today. We draw upon historical documents, such as the Sejong-Sillok (Veritable Records of King Sejong), Donggyeong-Jiji (Chorography of the Joseon Dynasty), and Yuanshi (History of the Yuan Dynasty), as well as related extant relics. The primary features of King Sejong’s Angbu-ilgu were as follows. First, celestial-circumference degrees were intricately engraved along the meridian line. Second, 12 double-hours were represented by images corresponding to their respective animal divinities. Third, a plate was affixed to the end of the gnomon, which stood perpendicular to the alidade, serving as a handle, rotated along two axes, and included a pinhole. Fourth, the diameter of the hemisphere measured 414 mm, approximately 1.5–2.1 times larger than extant Angbu-ilgu relics. Finally, four pillars supporting the Angbu-ilgu were positioned at four cardinal points. In conclusion, this study holds significance for restoring the Angbu-ilgu from the era of King Sejong.

이 연구는 중국 대학 태권도 지도자의 이미지가 선수의 그릿, 심리상태와 경기수행력에 미치는 영향을 연구하여 향후 중국 대학 태권도의 질적 발전을 위해 우수한 지도자양성 기초 자료를 제공하는 데 그 목적을 두고 있다. 이 연구를 위해 중국 허난성 대학교에 있는 선수를 대상으로 모집단을 선정하였으며, 편의표본추출법을 통해 표본을 추출하였다. 회수된 380부의 설문지 중, 응답이 불성실하고 또는 누락된 문 항이 있는 15부를 제외하여 총 365부를 결과처리에 사용하였다. 수집된 자료는 SPSS 23.0 프로그램을 사 용하여 빈도분석, 상관관계분석, 신뢰도분석, 탐색적 요인분석 및 다중회귀분석을 통해 실시했다. 이 연구 의 결과는 다음과 같다. 첫째, 지도자 이미지의 하위요인인 지도자의 사회활동과 직업의식, 자질, 업무, 역 할은 태권도 선수의 그릿에 유의한 영향을 미치는 것으로 나타났다. 둘째, 지도자 이미지의 하위요인인 지 도자의 사회활동과 직업의식, 자질, 태도, 업무, 역할은 태권도 선수의 심리상태에 유의한 영향을 미치는 것으로 나타났다. 셋째, 지도자 이미지의 하위요인인 지도자의 사회활동과 직업의식, 자질, 태도는 태권도 선수의 경기수행력에 유의한 영향을 미치는 것으로 나타났다.

Aluminum alloys, known for their high strength-to-weight ratios and impressive electrical and thermal conductivities, are extensively used in numerous engineering sectors, such as aerospace, automotive, and construction. Recently, significant efforts have been made to develop novel aluminum alloys specifically tailored for additive manufacturing. These new alloys aim to provide an optimal balance between mechanical properties and thermal/ electrical conductivities. In this study, nine combinatorial samples with various alloy compositions were fabricated using direct energy deposition (DED) additive manufacturing by adjusting the feeding speeds of Al6061 alloy and Al-12Si alloy powders. The effects of the alloying elements on the microstructure, electrical conductivity, and hardness were investigated. Generally, as the Si and Cu contents decreased, electrical conductivity increased and hardness decreased, exhibiting trade-off characteristics. However, electrical conductivity and hardness showed an optimal combination when the Si content was adjusted to below 4.5 wt%, which can sufficiently suppress the grain boundary segregation of the α- Si precipitates, and the Cu content was controlled to induce the formation of Al2Cu precipitates.

한국의 정원수는 2015년 7개에서 2022년 98개로 급격히 증가하였다. 늘어나는 정원 인프라의 수에 비해서 유지관리를 위한 지속적 정책과 연구는 미진한 상황이다. 본 연구는 효율 적인 정원 관리 정책을 도출하기 위해 주민들의 인식을 조사 하였다. 토픽 모델링, 감성 분석 등 텍스트 마이닝을 활용해 정원 참여 유형에 따른 주민 인식을 조사하였다. 주민 주도 정 원 그룹에서는 ‘정원정책’, 관 주도 정원 그룹에서는 ‘주민에 게 미치는 영향’이라는 주제에 의견이 집중되었다. 감성 분석 에서는 주민 주도 정원 그룹이 관 주도 정원 그룹보다 긍정어 점수가 더 높았다. 이러한 결과는 주민과 만족도 사이에 강한 사회적 연결이 있음을 나타낸다. 또한 주민 주도 정원 그룹에 서는 유지관리 업무를 맡은 주민들이 이를 자기계발의 한 형 태로 여기는 것으로 나타났다. 이러한 결과는 주민 주도 정원 관리 유형이 정원정책에 시사하는 바가 크며, 정원 내 일자리 와도 관련이 있음을 알 수 있다.

Numerous Sundials were fabricated during the reign of King Sejong of the Joseon Dynasty. One among them is Jeongnam-Ilgu (the Fixing-South Sundial), where the time can be measured after setting up the suitable meridian line without a compass. We reconstructed the new Jeongnam-Ilgu model based on the records of ‘Description of Making the Royal Observatory Ganui (簡儀臺記)’ in the Veritable Record of King Sejong. Jeongnam-Ilgu has a summer solstice half-ring under a horizontal ring which is fixed to two pillars in the north and south, and in which a declination ring rotates around the polar axis. In our model, the polar axis matches the altitude of Hanyang (that is Seoul). There are two merits if the model is designed to install the polar axis in the way that enters both the north and south poles and rotates in them: One is that it is possible to fix the polar axis to the declination ring together with the cross-strut. The other is that a twig for hanging weights can be protruded on the North Pole. The declination ring is supposed to be 178 mm in diameter and is carved on the scale of the celestial-circumference degrees on the ring’s surface, where a degree scale can be divided into four equal parts through the diagonal lines. In addition, the time’s graduation that is drawn on the summer solstice half-ring makes it possible to measure the daytime throughout the year. An observational property of Jeongnam-Ilgu is that a solar image can be obtained using a pin-hole. The position cast by the solar image between hour circles makes a time measurement. We hope our study will contribute to the restoration of Jeongnam-Ilgu.

Smart farm is a high-tech type of plant factory that artificially makes environmental conditions suitable for the growth of plants and manages them to automatically produce the desired plants regardless of seasons or space. This study was conducted by identifying the effects of Hertz and Duty ratio on the photosynthetic rate of ginseng, a medicinal crop, to find the optimal conditions for photosynthetic responses in smart farms. The light sources consisted of a total of 10 chambers using LED system, with 4 R+B (red+blue) mixed lights and 6 R+B+W (red+blue+white) mixed lights. In addition, the Hertz of the R+B mixed light was treated at 20, 60, 180, 540, 1620 and 4860 hz respectively. The R+B+W mixed light was treated with 60, 180, 540, and 1620 hz. Afterwards, experiments were conducted with the duty ratio of 30, 50, and 70%. As a result, the photosynthetic rate of ginseng according to duty ratio and Hertz was the highest at 60 hz when duty ratio was set to 50%. On the other hand, that was the lowest when the duty ratio was 30% at the same 60 hz. In addition, the photosynthetic rates were highest in the R+B mixed light and R+B+W mixed light at 60 hz. Therefore, the condition with the highest photosynthetic rate of ginseng in smart farms is 60 hz when the duty ratio in R+B mixed light is 50%.

We investigated the growth response and population regeneration of four halophyte species: Suaeda japonica, Salicornia europaea, Suaeda maritima and Suaeda glauca, when climate change proceeds caused by increased CO2 concentration and temperature. The plants collected from habitat in 2018 were transplanted into Wagner pots, and cultivated for two years in greenhouse divided into a control (ambient condition) and a treatment (elevated CO2+elevated temperature). The shoot length of halophytes was measured in July of each year, and the population regeneration rate was measured in October 2019. The shoot lengths of S. japonica and S. glauca had no difference between control and treatment for two years. Those of S. europaea were longer in control than treatment for two years. Those of S. maritima had no difference between control and treatment in 2018 but were longer in control than treatment in 2019. In control, the shoot lengths of S. japonica, S. europaea and S. glauca had no difference between years while those of S. maritima were longer in 2018 than in 2019. In treatment, those of S. japonica, S. europaea and S. maritima were shorter in 2019 than 2018 but S. glauca had no difference between years. The regeneration rates of S. japonica, S. europaea and S. glauca were lower treatment than control, and there was no difference in the regeneration rate of S. maritima. In conclusion, if climate change progresses caused by the increase of CO2 concentration and temperature, the shoot lengths of S. japonica, S. europaea and S. maritima will be shortened, and the regeneration rate of population will be increased only in the S. maritima.

In this study, two types of thick steel plates are prepared by controlling carbon equivalent and nickel content, and their microstructures are analyzed. Tensile tests, Vickers hardness tests, and Charpy impact tests are conducted to investigate the correlation between microstructure and mechanical properties of the steels. The H steel, which has high carbon equivalent and nickel content, has lower volume fraction of granular bainite (GB) and smaller GB packet size than those of L steel, which has low carbon equivalent and nickel content. However, the volume fraction of secondary phases is higher in the H steel than in the L steel. As a result, the strength of the L steel is higher than that of the H steel, while the Charpy absorbed energy at -40 °C is higher than that of the L steel. The heat affected zone (HAZ) simulated H-H specimen has higher volume fraction of acicular ferrite (AF) and lower volume fraction of GB than the HAZ simulated L-H specimen. In addition, the grain size of AF and the packet sizes of GB and BF are smaller in the H-H specimen than in the L-H specimen. For this reason, the Charpy absorbed energy at -20 °C is higher for the H-H specimen than for the L-H specimen.

PURPOSES : The purpose of this study is to analyze the improvement effect of the distributed arrangement of a vehicle base, which is a policy on maximizing the cost efficiency and timely/spatial effectiveness of special transportation system (STS) operation for improving the mobility of the elderly and disabled. METHODS: (1) The characteristics of the current distributed arrangement of an STS vehicle base in an urban area was analyzed. (2) The quantitative improvement effect was derived by analyzing the actual measurement of operation during STS distributed arrangement test operation in Namyangju city. RESULTS : (1) Cities with large area and populations, which have a distributed living zone in an urban area, have a higher distributed arrangement ratio than urbanized smaller cities. (2) Based on the effectiveness analysis of the STS distributed arrangement test operation, the total travel time and distance decreased. CONCLUSIONS : (1) For the STS distributed arrangement, parking spots, driver standby, and restrooms must be prepared. Facilitating STS as a public institution consignment makes it easier to secure a vehicle base and management by utilizing public facilities. (2) Implementing the STS distributed arrangement of vehicle base allows for efficient response to demand through effective management of vehicles, which eventually decreases travel time and distance. This decrease not only reduces management costs but also increases supply expansion without an increase in the number of vehicles.

The point-of-use water dispenser systems are widely used because of convenience in handling and demand for high-quality drinking water. The application has been increased recently in the public places such as department stores, universities and the rest areas in express ways. Improvement of water qualities by the dispenser systems was compared with tap water in this study. The tap water is supplied to the dispenser as the influent of the dispenser system. The twelve dispensers in the public places were used. The five dispensers used reverse osmosis as the main filter and other dispensers used various filters such as ultrafiltration, nanofiltration, and alumina filter. The water quality indicators for sanitation safety, i.e., turbidity and total coliforms, were evaluated. Other water qualities such as pH, residual chlorine, heterotrophic plate count (HPC), and total cell counts were also analyzed. By the point-of-use water dispenser, the turbidity, residual chlorine and pH were decreased and the HPC and total cell counts were increased. The t-test results revealed that the HPC of the tap waters were not significantly different from the treated waters but the total cell counts of the two groups were significantly different. The low pH of the RO filter treatment was also significantly different from the tap waters. This study will contribute to understand the role of the point-of-use water dispenser in improving water quality and to identify key water quality for the proper maintenance of the dispenser systems.

This study attempts to analyze the physicochemical characteristics of rice flour developed as rice powder for exclusive use, steamed rice cake recipes developed as basic recipefor rice cakes. The study also aims to compare the quality characteristics of steamed rice cakes in an effort to establish the possibilities of developing various rice cake recipes. The moisture content and amylose content increased as the rice powder particles for exclusive use became finer. With regards to water uptake, in the case of the Hungara type, the water uptake increased as rice powder particles increased in size. In the case of the Shingil and commercial types, the water uptake decreased as rice powder particles increased in size, and solubility and swelling force decreased as rice powder particles increased in size. In the case of chromaticity, Sulgidduk made with rice powder for exclusive use the brightness (L value) increased as powder particles became finer and the yellow indexes (b value) decreased, and this was especially pronounced in the Shingil type. The measurements of changes in the mechanical textures of Sulgidduk showed that rice types with larger particles led to lower hardness, cohesiveness, springiness, and chewiness.