• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.918-923
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• 2018

The main function of a fuel tank is to store fuel. On the other hand, the structural soundness of the fuel tank is related directly to the survival of the crew in an emergency situation, such as an aircraft crash, and the relevant performance is demonstrated by a crash impact test. Because crash impact tests have a high risk of failure due to the high impact loads, various efforts have been made to minimize the possibility of trial and error in the actual test at the beginning of the design. Numerical analysis performed before the actual test is a part of such efforts. For the results of numerical analysis to be reflected in the design, however, the reliability of numerical analysis needs to be ensured. In this study, the results of numerical analysis and actual test data were compared to ensure the reliability of numerical analysis for the crash impact test of a rotorcraft fuel tank. For the numerical analysis of a crash impact test, LS-DYNA, crash analysis software, was used and the ALE (arbitrary Lagrangian Eulerian) technique was applied as the analysis method. To obtain actual test data, strain gages were installed on the metal fittings of the fuel tank and linked to the data acquisition equipment. The strain and stress of the fuel tank fitting were calculated by numerical analysis. The reliability of the numerical analysis was enhanced by assessing the error between the strain measurement of the upper fitting obtained from an actual fuel tank and the strain calculated from numerical analysis.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.462-469
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• 2021

Maesa japonica (Thunb.) Moritzi & Zoll. is a rare evergreen shrub that occurs in west Gotjawal, Jeju island, Korea. This study was conducted to investigate effects of an artificial shading on flowering and growth characteristics of M. japonica seedlings. The level of shading had been set to be 35%, 55% and 75% using shading net. The stage of flowering and flowering ratio, seedling height, the number of leaves and stems, leaf area were measured. Flowering timings were delayed by shading. The number of flowering seedlings per plot and inflorescences per seedling were the most in 55% shading level. Tendency of decreased seedling height with increased shading level was shown. The number of leaves and stems were the fewest values in 75% shading level. The increased biomass with decreased shading level was statistically significant. Aboveground and underground biomass were 2.1 and 1.7 times higher in shading 35% than in shading 75%, respectively. Meanwhile, all seedlings in non-shading plots were dead in winter. Such might be speculated as results of the light stress. As a result, we conclude that M. japonica vitally demands the shading for growth and the optimal shading levels for growth and flowering are 35% and 55%, respectively.

• Tunnel and Underground Space
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• v.31 no.5
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• pp.333-359
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• 2021

Gases such as hydrogen and radon can be generated around the canister in high-level radioactive waste disposal systems due to several reasons including the corrosion of metal materials. When the gas generation rate exceeds the gas diffusion rate in the low-permeability bentonite buffer, the gas phase will form and accumulate in the engineered barrier system. If the gas pressure exceeds the gas entry pressure, gas can migrate into the bentonite buffer, resulting in pathway dilation flow and advective flow. Because a sudden occurrence of dilation flow can cause radionuclide leakage out of the engineered barrier of the radioactive waste disposal system, it is necessary to understand the gas migration behavior in the bentonite buffer to quantitatively evaluate the long-term safety of the engineered barrier. Experimental research investigating the characteristics of gas migration in saturated bentonite and research developing numerical models capable of simulating such behaviors are being actively conducted worldwide. In this technical note, previous gas injection experiments and the numerical models proposed to verify such behaviors are introduced, and the future challenges necessary for the investigation of gas migration are summarized.

• (The)Korea Educational Review
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• v.23 no.1
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• pp.165-182
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• 2017

The purpose of this research is to examine So-Hak(小學) and Seodang(書堂) education, which were at the heart of child-adolescent education in Cho-Sun dynasty, and their implications on character education. In other words, this research is an attempt to review a traditional education from a modern character education perspective. So-Hak contains as major educational concepts Hyo(孝) and Kyeong(敬), guiding principles of daily lives. In this research, two basic concepts of So-Hak were reinterpreted from a modern perspective, namely, Soe-So-Eung-Dae-Jin-Tae(灑掃應對進退) and Ye-Ak-Sa-Eu-Seo-Su(禮樂射御書數). One of major implications of So-Hak lies on the habituation of what is learned, for habit leads to continuation of action, out of which the development of character emerges. As such, the role of habituation in character education is twofold, namely, basic educational content and method. Seodang is a school in which the teachings of So-Hak is realized. From an educational method perspective, Seodang's teaching-learning methods of reading, writing, and calligraphy methods were examined. As a result, three implications of So-Hak and Seodang were drawn, the habituation of what is learned, unification of knowledge and morality, and individualized learning based on one's own level.

• The Journal of Korean Philosophical History
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• no.30
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• pp.259-282
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• 2010

Ethical value of Confucianism seeks to realize the ideal of life to the reality, through ethical life. It is discussed based on myself, which is the main ethical agent, in relationship with the others. These traditional values include universality in the homogeneous aspect such as humanism that has been commonly sought by the human race, or awe toward the absolute one. 'Pursuit of universality in the Korean context' ultimately seeks 'Korean ethics', that prevailed in Korea, based on the Korean traditional culture. Therefore, we should comprehensively understand this universality and diversity, so called 'us'. Through the understanding, we should play an active role of culture creators as noble persons that realize fraternity, along with respect to each culture. Studies on traditional ethics will not only be an important opportunity to look at the history and current status of ethics, but also it will be a cornerstone to understand the Korean mind-set based on the Korean culture. Recently, establishing Korean identity and recovery of ethics damaged due to anomie of value are key social issues. Studies on traditional value are not separated from this issue. If our adolescents are able to correctly understand the traditional ethics and pursue a life recreating it, they will be able to enjoy healthier life, contributing to a healthier society.

• (The)Study of the Eastern Classic
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• no.32
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• pp.215-244
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• 2008

This article's aim is to criticise ontological physicallism, supervenience, and eliminativism on theory of mind-body relation, and to present Confucian theory of mind-body relation as an alternative. Confucianism on theory of mind-body relation. Ontological physicallism reduce 'the psycho' to 'the physical'. Therefore, Physicallism as theory of mind-body relation reduce mind to physical body. Mind-Body supervenience theory insists property co-variation and dependency of mind-body. Eliminative materialism is to eliminate 'the psycho'. But confucianists believe in reality of the human mind-heart & it's nature. Confucianism is to establish the mina-heart & it's nature as real. Confucianism can be an alternative of physicallism, supervenience, and eliminativism on theory of mind-body relation. And Confucian's opinion differs from theory of the substance and phenomenalism.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.377-387
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• 2020

The purpose of this study is a descriptive research study to identify the emotional labor, ethical climate, job satisfaction, and retention intention of nurses in general hospitals, and to identify the relationship between variables and factors influencing the retention intention. The study subjects were 198 nurses working in four general hospitals, and data were collected from September 18 to September 30, 2019 using a structured questionnaire. The collected data were analyzed by t-test, ANOVA, Pearson's correlation coefficients, and multiple regression using SPSS WIN 25.0. As a result of the study, there was a positive correlation between ethical climate(r=.345, p<.001) and job satisfaction(r=.388, p<.001), but emotional labor (r=-.153, p=.031) showed negative correlation. Factors influencing the retention intention of general hospital nurses are job satisfaction(β=.27, p=.001), age(β=.27, p<001), ethical climate(β=.16, p=044), and the explanatory power of the variable was 24.2%. In order to increase the retention intention of general hospital nurses, it is necessary to increase job satisfaction and create a sound ethical climate, and to develop an intervention program that can increase the retention intention by age.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.3
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• pp.229-235
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• 2021

Globally, due to climate change and urbanization, problems with water cycle destruction in urban areas frequently occur. In order to solve this problem, LID technique is being actively conducted the application in urban and research. In this study, some areas of the new city located in Busan was constructed using a widely used SWMM model to verify the effectiveness of the LID technique. This is to present a plan to maximize the efficiency of urban water cycle of the stormwater management target figure and the LID scale calculation method. In addition, the efficiency of runoff reduction using stormwater storage basin was analyzed in urban development projects. By calculating the scale of customized LID for each sub basin, the amount of runoff and peak runoff after LID application was reduced by 86.8 % and 69.5 %, respectively. Depending on the application of the stormwater storage basin, the reduction effect of peak runoff from 0.5 m³/s to 4.9 m³/s and delay effect of 8 minutes to 10 minutes was shown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.768-776
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• 2021

Current protection-coordination methods use the reverse time characteristics of the T-C curve, which is not effective for a LVDC distribution system because the protective operation time of converters and DC circuit breakers is much faster than AC protection devices. Therefore, an algorithm is proposed for fault-section isolation using the fault current slope to minimize the blackout region and coordinate between converters and protection devices in a rapid and accurate manner. The method deals with the slope characteristics of a fault current, which may depend on the fault location in an LVDC distribution system. Thus, an LVDC distribution system can be operated in a stable manner by isolating the fault section selectively before the shutdown of the main converter using slope characteristics, which change in proportion to the line impedance and fault location. A 1.5-kV LVDC distribution system was modeled to verify the effectiveness of the proposed algorithm using PSCAD/EMTDC. The system is composed of a distribution substation, LVDC converter, and distribution lines. The simulation results confirm that the proposed algorithm is a useful tool for minimizing the fault section in an LVDC distribution system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.487-495
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• 2021

The voltages mainly used in ships are 450 [V], 6.6 [kV], and 11 [kV], and an earthed system is applied to ensure the stability of the power distribution system. In general, low-voltage ships using 450 [V] apply an unearthed system, while high-voltage ships using 6.6 [kV] or 11 [kV] use a high-resistance earthed system. When an earth fault occurs in a ship's power distribution system, the voltage of the healthy phase increases to the line-to-line voltage or higher, which causes an excessive impact on the insulation of the cable. Thus, analyzing this behavior is very important. In this paper, we investigate the characteristics of the line-to-earth voltage variation according to earth faults and a recognition procedure of a faulty phase using the symmetrical coordinate method for a high-resistance earthed system and unearthed system. A mathematical model of the line-to-earth voltage was derived through the symmetric coordinate method, and the ship voltage for simulations was selected as 6.6 [kV] and 450 [V]. A MATLAB simulation proved that this method can determine the highest increase of the line-to-earth voltage, which leads by 120° on the faulty phase, and it accurately judges the faulty phase in both earthed systems.