• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.16 no.4
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• pp.1-8
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• 2020

For a central cooling system of a medical facility composed of absorption chiller and screw chiller, the study was conducted on how to minimize the energy cost. In consideration of the energy cost, the optimal operation method in which the operation method of the heat source is changed according to the size of the cooling load was derived through simulation analysis. When applying the optimal operation method, the indoor environment, energy consumption, and energy cost were analyzed and compared with the reference operation method.

• Journal of Hydrogen and New Energy
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• v.32 no.6
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• pp.649-655
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• 2021

The recently proposed Kalina based power and cooling cogeneration cycles (KPCCCs) have shown improvement in the energy utilization of the system compared to the basic Kalina cycle. This paper suggests a combined tri-cogeneration system for power, heating and cooling based on the Kalina cycle. And thermodynamic performances of the suggested system based on the first and second thermodynamic laws are parametrically investigated with respect to the ammonia mass fraction and the boiler pressure. Results showed that the thermodynamic performance of the system could be greatly improved compared to the former KPCCCs.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.6
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• pp.281-286
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• 2021

Arc ion plating (AIP), laser cladding, and nitriding are methods that can prevent mold damage or repair and create cracks and breakages on the die surface. The dissolution and soldering behavior of coated SKD61 by using arc ion plating, laser cladding, and nitriding was investigated. The structure of the coating was investigated as a function of deposition conditions by X-ray diffraction and the crystallographic orientation was determined using the texture factor. The TiAlN film deposited with AIP showed excellent corrosion resistance in the molten aluminum alloy at 680℃. In this paper, we have detailed the corrosion and mass loss phenomena associated with these steel-cast metal interactions.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.18 no.4
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• pp.365-388
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• 1989

열병합발전시스템은 엔진 또는 가스터빈구동의 열병합발전설비이며, 전력과 열을 동시에 이용함으로써 높은 총합열효율이 기대되는 열원시스템이다. 그 경제성은 전력과 열의 수요가 년간을 통해서 안정하게 존재할 것이 필요조건으로 된다. 본보는 일년간의 운전기록을 사용하여 현재 가동하고 있는 시스템의 특성, 전력수요와 열부하의 실태를 분석하여 개략적으로 설명하는 것이다. 해석에 사용된 자료는 시간단위의 계획치, 적산치이며, 데이터입력후의 인산, 통계, 도표 작성등은 전부 전산기시스템으로써 처리하였다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.2
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• pp.108-117
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• 1985

In this study, a numerical analysis was performed for the natural convection heat transfer in a vertical channel which was consisted of two finite-thickness vertical walls with heat source. The ratio of the thermal conductivity of wall to air played an important role in the analysis. The case for which one side wall has protrusion resistances was also examined. The governing equations for the system was discretized by control volume formulation and solved by SIMPLE method. As the result of this study, it was found that the uniform heat flux boundary condition could be applied when the conductivity ratio was below approximately 50 and the uniform temperature boundary condition could be used when the conductivity rat io was over approximately 15,000. However, when the conductivity ratio was between 50 and 15,000, the thermal conductivity ratio value should be considered for the analysis. It was also found that the existence of protrusion resistance influenced the thermal field up to the distance of 3-4 times of the protrusion length.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.602-604
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• 2022

Recently, Korea has implemented the compulsory employment system for the disabled. The compulsory employment system for the disabled is a system that imposes an obligation on the state-local governments, public institutions that employ 50 or more full-time workers, and business owners of private companies to employ more than a certain percentage of the disabled. Accordingly, the expected effects of compulsory employment of the socially disadvantaged, including the disabled, were investigated.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.838-844
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• 2022

In this paper, an experimental study was conducted on the energy efficiency ratio of performance for air source heat pump. The energy efficiency ratio presents the operating efficiency of heat pump performance. In order to improve reliability in the energy efficiency ratio test of air source heat pump, the measurement uncertainty of the instrument was estimated. Measurement uncertainty refers to the uncertainty of a measurement, estimates the range in which the expected value of the measurement can be within a certain confidence level, and suggests a range in which the measured representative value is incorrect. The measurement uncertainty for the energy efficiency ratio test of air source heat pump was calculated and the measured results were presented.

• The Journal of the Society of Stroke on Korean Medicine
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• v.14 no.1
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• pp.23-30
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• 2013

■ Objectives This study is to examine change of gait parameters on shoes sole height(high heels, MBT shoes, house shoes) through gait analyzer. ■ Methods The subjects of this study were 12 women in their twenties. Gait analysis system is 5m in total length and gait is led to be comfortable. They put three kinds of shoes each and were led to walk 5m on gait analysis system. ■ Results There were significant differences in step length, single support and load response of gait parameters and in stride length and total double support at double support phase. ■ Conclusion Muscle activity differs in that different that shoes sole height and form because tibialis anterior muscle has strengthen and gastrocnemius has stretched. Therefore we think that patients with knee joint problem consider gait parameters when shoes select.

• Annual Conference of KIPS
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• 2021.11a
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• pp.1156-1159
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• 2021

수도권을 중심으로 한 부동산 가격 상승이 지속적으로 진행되고 있다. 한국은행에서는 기준금리 인상으로 과열된 부동산 시장의 안정을 바라고 있다. 하지만 기준금리 인상이 부동산 시장에 미치는 영향이 크지 않다고 보는 시각도 많다. 이에 본 논문에서는 머신러닝과 딥러닝을 이용하여 서울 지역의 부동산 매매지수를 예측하고 기준금리를 추가 변수로 이용하여 결과를 비교하였다. 실험 결과 선형적으로 증가 중인 시장 특성상 전통적 모델인 선형회귀가 우수한 성능을 보였으며, 기준 금리를 변수로 추가한 경우 예측력이 근소하게 증가하였으나 그 영향은 크지 않음을 볼 수 있었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.192-193
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• 2021

Recently, the need to strengthen the Air Environment Conservation Act and secure alternative heat sources during the winter by carbon neutrality policies has been raised. Accordingly, winter construction, which has safety and quality measures, is emerging as an essential factor. It is believed that eco-friendly tropical type electric hot air heaters will be able to solve most of the problems of winter construction at construction sites, especially prevention of suffocation and fire accidents. In addition, as a result of on-site performance verification, it has secured more than the same performance as the existing curing method, and the curing technology can create an eco-friendly and pleasant working environment while considering safety and construction.