• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.823-824
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• 2016

일반적으로 배전반, 분전반, 전동기제어반(Motor Control Center;MCC)은 집단거주지역, 빌딩, 학교, 공장, 항만, 공항, 상하수 처리장, 변전소, 중공업 플랜트 등의 광범위한 전력 수용가에 설치되어 특고압의 전력을 해당 설비들에 요구되는 전압으로 변환하여 공급하는데 사용된다. 이와 같은 배전반, 분전반, MCC에 포함되는 전기설비의 사고는 부스바 접속부의 열화에 의한 사고, 부스바의 접점 및 연결 부위에서의 접촉 불량에 의한 사고, 부스바 접속부의 과열 현상에 의한 사고로 구분된다. 본 논문에서는 부스바 접촉부의 볼트 및 너트의 풀림상태, 접촉부 열화 측정이 가능하며, 배전반 내부온도와 부스바 온도를 측정하여 추이변화에 대한 감시기능이 있는 부스바 접촉부 체결상태 모니터링 시스템을 제안한다. 제안된 시스템은 정량적인 부스바 체결상태 검출과 부스바 현재온도 검출의 이중적인 센싱에 의해 부스바 접촉부 정상여부 판별이 가능하여 전기설비 사고를 줄일 수 있을 것으로 기대된다.

• 한국의사학회지
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• 제31권2호
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• pp.27-40
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• 2018

Sauna, or hanjeung (汗蒸) is a physical sweating method that uses external heat to forcibly raise body temperature to treat cold damage disorders (傷寒) in traditional Korean medicine. This study focuses on the fact that the sauna was recorded as a healing and bathing method on the Vinaya Pitaka (律藏), and investigates the records of folk sauna therapy of Joseon Dynasty from the perspective of Buddhist medicine which played a significant role in ancient medicine history in Korea. Although the word 'hanjeung (汗蒸)' first appeared in "The Veritable Records of King Sejong (世宗實錄)" in the Korean literature, this study aims to confirm the possibility that the tradition of Buddhist sauna bathing has already existed since the Three Kingdoms period in Korea, based on the fact that sauna bathing was recorded in the Vinaya Pitaka and that the ancient Buddhist bathing culture was introduced in ancient Japan. In addition, the succession of the Buddhist sauna tradition by Goryeo will be traced back through the records of 1920s urban saunas in Gaesung (개성) which was the old capital of Goryeo and had a strong tendency to adhere to traditional Goryeo customs. Finally, the study tries to identify the elements of the Buddhist sauna bathing on the records of folk sauna therapy in the Joseon Dynasty. As a result, this study examines how the Buddhist sauna bathing culture in ancient Korea, which was led by medical monks, spread in the general public and influenced the folk sauna therapy in the Joseon Dynasty.

• 대한건축학회논문집:구조계
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• 제34권2호
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• pp.75-82
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• 2018

Green roof in Korea has been recognized as part of landscape area and local governments enacted municipal ordinance for supporting green roof thereby assisting part of expenses spent for green roof within a range of budget for buildings which are eligible for the green roof support of existing buildings. However, it is necessary to enforce a regulation of mandatory green roof for new buildings in order to expand green roof application and provide a variety of assistances such as subsidy payment, tax relief, and mitigation of floor area ratio-related regulation as done in other advanced nations. In particular, LEED(Leadership in Environmental and Energy Design) in the USA applies additional point directly for green roof in terms of the reduction in heat island effects. For example, the following items are beneficial to have additional points: habitat preservation or restoration, external space, rainwater management, reduction in outdoor water usage, minimum energy performance, and optimum energy performance. In addition, the BREEAM(Building Research Establishment Environmental Assessment Method) in the UK specifies green roof as one of assessment items to be complied in terms of diversity of species. As such, LEED and BREEAM reflect direct and indirect effects of green roof on assessment criteria, which suggest a direction to green building certification criteria in Korea where only additional points are given for green roof according to soil depth.

• 산업경영시스템학회지
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• 제44권2호
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• pp.85-92
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• 2021

Ambient Air Vaporizer (AAV) is an essential facility in the process of generating natural gas that uses air in the atmosphere as a medium for heat exchange to vaporize liquid natural gas into gas-state gas. AAV is more economical and eco-friendly in that it uses less energy compared to the previously used Submerged vaporizer (SMV) and Open-rack vaporizer (ORV). However, AAV is not often applied to actual processes because it is heavily affected by external environments such as atmospheric temperature and humidity. With insufficient operational experience and facility operations that rely on the intuition of the operator, the actual operation of AAV is very inefficient. To address these challenges, this paper proposes an artificial intelligence-based model that can intelligent AAV operations based on operational big data. The proposed artificial intelligence model is used deep neural networks, and the superiority of the artificial intelligence model is verified through multiple regression analysis and comparison. In this paper, the proposed model simulates based on data collected from real-world processes and compared to existing data, showing a 48.8% decrease in power usage compared to previous data. The techniques proposed in this paper can be used to improve the energy efficiency of the current natural gas generation process, and can be applied to other processes in the future.

• 한국기계가공학회지
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• 제21권8호
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• pp.25-31
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• 2022

Recently, investment in the aerospace industry has increased, and titanium alloys have been widely adopted for manufacturing parts in the aerospace industry. The Ti-6Al-4V alloy has high strength in high-temperature and high-pressure environments and is evaluated as a material with excellent heat, corrosion, and abrasion. However, titanium alloys are expensive, difficult to cut, and possess a large cutting load during the drilling process. In this study, the cutting force generated in the drilling process of Ti-6Al-4V alloy was verified via finite element analysis (FEM) and cutting force measurement experiments. A structural analysis was performed based on the cutting analysis data to verify the plastic deformation occurring during the drilling process of cylindrical Ti-6Al-4V alloy aircraft parts. Methods were proposed to predict the amount of deformation that occur during the manufacturing process of titanium-alloy aircraft parts and control the external environment, to minimize the amount of deformation.

• BMB Reports
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• 제55권10호
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• pp.512-517
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• 2022

Traumatic brain injury (TBI) is brain damage which is caused by the impact of external mechanical forces. TBI can lead to the temporary or permanent impairment of physical and cognitive abilities, resulting in abnormal behavior. We recently observed that a single session of early exercise in animals with TBI improved their behavioral performance in the absence of other cognitive abnormalities. In the present study, we investigated the therapeutic effects of continuous exercise during the early stages of TBI in rats. We found that continuous low-intensity exercise in early-stage improves the locomotion recovery in the TBI of animal models; however, it does not significantly enhance short-term memory capabilities. Moreover, continuous early exercise not only reduces the protein expression of cerebral damage-related markers, such as Glial Fibrillary Acid Protein (GFAP), Neuron-Specific Enolase (NSE), S100β, Protein Gene Products 9.5 (PGP9.5), and Heat Shock Protein 70 (HSP70), but it also decreases the expression of apoptosis-related protein BAX and cleaved caspase 3. Furthermore, exercise training in animals with TBI decreases the microglia activation and the expression of inflammatory cytokines in the serum, such as CCL20, IL-13, IL-1α, and IL-1β. These findings thus demonstrate that early exercise therapy for TBI may be an effective strategy in improving physiological function, and that serum protein levels are useful biomarkers for the predicition of the effectiveness of early exercise therapy.

• 한국분말재료학회지
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• 제29권6호
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• pp.492-498
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• 2022

N-doped Na₂Ti₆O₁₃@TiO₂ (denoted as N-NTO@TiO₂) composites are successfully synthesized using a simple two-step process: 1) ball-milling of TiO₂ with Na₂CO₃ followed by heat treatment at 900℃; 2) mixing of the prepared Na₂Ti₆O₁₃ with titanium isopropoxide and calcining with urea at 500℃. The prepared composites are characterized using XRD, SEM, TEM, FTIR, and BET. The N-NTO@TiO₂ composites exhibit well-defined crystalline and anatase TiO₂ with exposed {101} facets on the external surface. Moreover, dopant N atoms are uniformly distributed over a relatively large area in the lattice of the composites. Under visible light irradiation, ~51% of the aqueous methylene blue is photodegraded by N-NTO@TiO₂ composites, which is higher than the values shown by other samples because of the coupling effects of the hybridization of NTO and TiO₂, N-doping, and presence of anatase TiO₂ with exposed {101} facets.

• 한국추진공학회지
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• 제27권1호
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• pp.49-57
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• 2023

자가증기 가압시스템은 저비용, 고신뢰도의 장점으로 차세대 재사용 발사체들의 추진기관에 널리 채택되고 있다. 자가증기 가압시스템은 구조가 간단하나 탱크 내부에서 일어나는 열과 물질의 전달과정에 대한 이해가 필요하다. 이러한 이유로 자가증기 가압시스템의 모사시험을 구상하였다. 모사시험설비는 해외 가압시험설비 사례와 전문가의 자문을 기반으로 구성하였는데, 실제 자가증기 가압시스템과 달리 추진제 탱크를 단열하여 외부환경에 의한 영향을 배제하고자 하였으며, 열과 물질 전달현상의 연구의 편의를 위하여 가압가스 공급라인과 추진제 배관을 분리하였다. 제작된 자가증기가압 모사시험설비를 이용하여 극저온 추진제에서 가압가스의 응축현상, 헬륨을 이용한 가압과 증발된 추진제를 이용한 자가증기가압의 효율성 비교, 그리고 자가증기의 온도에 따른 가압능력을 평가할 수 있다.

• 한국생활환경학회지
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• 제21권6호
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• pp.959-964
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• 2014

Energy performance of building envelope components, including external walls, floors, roofs, windows and doors, is crutial for determining how much energy is required for heating and cooling in a building. Among various building technologies, a green roof system can be a good option for reducing heat gain and loss in new buildings as well as existing buildings for green remodeling. This paper evaluates the performance of green roof systems according to soil depth and Leaf Area Index (LAI) for existing buildings. It also attempts to quantify the energy saving effects on new and existing buildings with different insulation levels. Thermal performance of green roofs is mainly dependent on soil thickness and LAI. Installation of green roofs in deteriorated existing buildings can lead to improvements in roof insulation, due to the soil layer. An increase in soil depth leads to a decrease in heating load, regardless of conditions of vegetation on the green roof. Larger LAI values may reduce cooling loads in the cooling season. Installation of green roof in deteriorated existing buildings showed bigger energy saving effect in comparison to a case in new buildings. A simulation study showed that the installation of green roof systems in deteriorated existing buildings with low insulation levels, due to low thermal performance requirements when constructed, could improve the energy performance of the buildings similar or better to the peformance on new buildings with the most updated insulation standard. Thus, when remodeling a deteriorated building, green roofs could be a good option to meet the most recent energy requirements.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.9-18
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• 2024

In-vessel retention through external reactor vessel cooling (IVR-ERVC) is a severe accident management (SAM) strategy that has been adopted and used in many nuclear reactors such as AP1000, APR1400, and light water reactor etc. Some reactor accidents have raised concerns about nuclear reactors among residents, leading to a decrease in residents' acceptability and many studies on SAM are being conducted. Experiments on IVR-ERVC are almost impossible due to its specificity, so fluid characteristics are analyzed through BALI experiments with similar condition. In this study, computational fluid dynamics (CFD) via Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) for BALI experiments were performed. Steady-state CFD analysis was performed on three turbulence models, and SST k-ω model was in good agreement with the experimental measurement temperature within the maximum error range of 1.9%. LES CFD analysis was performed based on the RANS analysis results and it was confirmed that the temperature and wall heat flux for depth was consistent within an error range of 1.0% with BALI experiment. The LES CFD analysis results were compared with those of the Lagrangian-based solver. LES matched the temperature distribution better than SOPHIA, but SOPHIA calculated the position of boundary between stratified layer and convective layer more accurately. On the other hand, Lagrangian-based solver predicted several small eddy behaviors of the convective layer and LES predicted large vortex behavior. The vibration characteristics near the cooling part of the BALI experimental device were confirmed through Fast Fourier Transform (FFT) investigation. It was found that the power spectral density for pressure at least 10 times higher near the side cooling than near the top cooling.