• 문화기술의 융합
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• 제8권3호
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• pp.543-550
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• 2022

코로나 19 시대에서 국내 건설현장 또한 그 영향에서 벗어날 수 없으며, 이를 예방하기 위해 현장 방역·위생관리 강화, 인원 간 대면 접촉을 최소화하는 등 노력을 기울이고 있다. 특히 안전보건교육 운영상에 있어 교육 인원 규모 축소 등 많은 변화가 있으며 안전보건교육 소홀로 인한 재해 발생 증가 우려의 목소리 또한 높아지고 있다. 이에 본 연구는 현장의 안전보건교육의 실태조사를 통해 포스트 코로나 시대에 부합하는 교육방향을 설정하고자 하며 이를 통해 사고감축에 기여하기 바란다.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.52-61
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• 2017

Considering its significant impact on the cost and schedule of construction projects, formwork as one part of temporary facility categories in construction should be arranged precisely. Current practice in the formwork planning is often conducted manually and repetitively, causing low efficiency and time waste. This study proposes an automated framework to generate more accurate and detailed formwork plans by utilizing information from building information modeling (BIM) considering the adequate geometric and semantic information provided by the BIM model. The dimensions and quantities information of elements in a building can be extracted automatically. Then, a rule is prepared for calculating the required forms erected around elements based on the contact areas. Finally, an algorithm of integrating first fit decreasing (FFD) with coordinated bottom left (CBL) is applied to automatically generate the formwork plan. The BIM-based automated planning framework is demonstrated by an illustrative example. The results show that the proposed framework can generate the formwork plan accurately and automatically, and significantly improve the efficiency in the formwork plan and reuse.

• 한국중재학회지:중재연구
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• 제31권4호
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• pp.119-136
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• 2021

Due to the restriction of movement caused by the Corona epidemic and the expansion of the "big face" through human distance, the "unmanned system" based on artificial intelligence and the Internet of Things has been widely used in modern life. "Self-driving," one of the transportation systems based on artificial technology, has taken the initiative in the transportation system as the spread of Corona has begun. Self-driving technology eliminates unnecessary contact and saves time and manpower, which can significantly impact current and future transportation. Accidents may occur, however, due to the performance of self-driving technology during transportation albeit the U.S. allows ordinary people to drive automatically through experimental operations, and the product liability law will resolve the dispute. Self-driving has become popular in the U.S. after the experimental stage, and in the event of a self-driving accident, product liability should be applied to protect drivers from complicated self-driving disputes. The purpose of this paper is to investigate whether disputes caused by defects in ordinary cars can be resolved through arbitration through U.S. precedents and to investigate whether disputes caused by defects in autonomous cars can be arbitrated.

• Tribology and Lubricants
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• 제39권6호
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• pp.244-249
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• 2023

This paper presents a comprehensive analysis of the impact of surface roughness on the friction and wear properties of SUS 321, an austenitic stainless steel variant produced using the laser powder bed fusion (LPBF) technique, which is a prevalent additive manufacturing method. After the LPBF fabrication, the specimens go a heat treatment process aimed at alleviating residual stress. Subsequently, they are polished extensively to achieve a refined and smooth surface. To deliberately introduce controlled variations in surface roughness, an etching process is employed. This multi-step method encompassed primary etching in a 3M hydrochloric acid solution, followed by secondary etching in a 35 wt% ferric chloride solution, with varying durations applied to different specimens. A comprehensive evaluation of the surface characteristics ensued, employing precise techniques such as surface roughness measurements and meticulous assessments of water droplet contact angles. Following the surface treatment procedures, a series of friction tests are performed to explore the tribological behavior of the etched specimens. This in-depth investigation reached its peak by revealing valuable insights. It clarified a strong correlation between intentionally altered surface roughness, achieved through etching processes, and the resulting tribological performance of LPBF-fabricated SUS 321 stainless steel. This significantly advances our grasp of material behavior in tribological applications.

• Current Optics and Photonics
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• 제8권3호
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• pp.246-258
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• 2024

In aerospace and energy engineering, the reconstruction of three-dimensional (3D) temperature distributions is crucial. Traditional methods like algebraic iterative reconstruction and filtered back-projection depend on voxel division for resolution. Our algorithm, blending deep learning with computer graphics rendering, converts 2D projections into light rays for uniform sampling, using a fully connected neural network to depict the 3D temperature field. Although effective in capturing internal details, it demands multiple cameras for varied angle projections, increasing cost and computational needs. We assess the impact of camera number on reconstruction accuracy and efficiency, conducting butane-flame simulations with different camera setups (6 to 18 cameras). The results show improved accuracy with more cameras, with 12 cameras achieving optimal computational efficiency (1.263) and low error rates. Verification experiments with 9, 12, and 15 cameras, using thermocouples, confirm that the 12-camera setup as the best, balancing efficiency and accuracy. This offers a feasible, cost-effective solution for real-world applications like engine testing and environmental monitoring, improving accuracy and resource management in temperature measurement.

• 소성∙가공
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• 제33권2호
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• pp.112-117
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• 2024

In this study, the friction and wear characteristics of Inconel 600 in the superplastic forming process of Ti6Al4V were evaluated through pin-on-disc tests. To achieve an efficient and systematic experimental design, the Taguchi method was employed. The wear track of the Inconel 600 pin showed scratches in the sliding contact direction, confirming that the wear mechanism is abrasive wear. Through sensitivity analysis such as ANOVA and Main effects, it was confirmed that both normal force and sliding distance have a significant impact on the wear. Changes in sliding velocity and distance did not affect the friction coefficient, which remained relatively constant at approximately 0.380. The wear prediction model for Inconel 600 in the superplastic forming of Ti6Al4V was constructed, which can be utilized as a guideline for the prediction and management of tool wear.

• Journal of applied mathematics & informatics
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• 제42권4호
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• pp.945-968
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• 2024

This study focuses on SIR model for SARS-CoV-2. The SIR model classifies a population into three compartments: susceptible S(t), infected I(t), and recovered R(t) individuals. The SARS-CoV-2 model considers various factors, such as immigration, birth rate, death rate, contact rate, recovery rate, and interactions between infected and healthy individuals to explore their impact on population dynamics during the pandemic. To analyze this model, we employed two powerful semi-analytical methods: the Laplace Adomian decomposition method (LADM) and the differential transform method (DTM). Both techniques demonstrated their efficacy by providing highly accurate approximate solutions with minimal iterations. Furthermore, to gain a comprehensive understanding of the system behavior, we conducted a comparison with the numerical simulations. This comparative analysis enabled us to validate the results and to gain valuable understanding of the responses of SARS-CoV-2 model across different scenarios.

• 방사성폐기물학회지
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• 제22권1호
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• pp.37-44
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• 2024

In 2017, a decision was made to permanently shut down Kori Unit 1, and preparations began to be made for its decontamination and decommissioning. The dismantling of the biological shields concrete, reactor vessel (RV), and reactor vessel internals (RVI) is crucial to the nuclear decommissioning process. These components were radiologically activated by the neutron activation reaction occurring in the reactor during its operational period. Because of the radioactivity of the RV and RVI of Kori Unit 1, remotely controlled systems were developed for cutting within the cavity to reduce radiation exposure. Specialized equipment was developed for underwater cutting operations. This paper focuses on modeling related to RVI operations using the MAVRIC code and the dose calculation for a diver entering the cavity. The upper and lower parts of the RVI are classified as low-level radioactive waste, while the sides that came into contact with the fuel are classified as intermediate-level radioactive waste. Therefore, the modeling presented in this paper only considers the RVI sides because the upper and lower parts have a minimal impact on the radiation exposure. These research findings are anticipated to contribute to enhancing the efficiency and safety of nuclear reactor decommissioning operations.

• 한국산학기술학회논문지
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• 제21권11호
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• pp.843-850
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• 2020

본 연구의 목적은 국내 위험물 운송용 탱크화차의 충돌안전설계 가이드라인 제안을 위해 해외 충돌안전 기준에 따른 국내 위험물 운송화차에 대하여 비선형 충돌해석을 하여 위험성을 평가하고, 구조적 취약부를 분석하는데 있다. 유럽의 EN 12663-2에서 규정하는 화차의 완충시험 및 북미 49CFR179에서 규정하는 탱크 펑크시험기준을 분석하였으며, 상용 유한요소 해석 솔버인 LS-DYNA를 이용하여 각각 기준에 따른 비선형 유한요소모델을 모델링하였다. EN 규격의 완충시험 해석결과 충돌속도 6 km/h 이하에서는 소성변형이 발생하지 않을 것으로 예측하였지만, 8 km/h 이상의 충돌속도에서 중앙연결기를 통한 하중 전달으로 차체의 센터실 후방 및 탱크 중앙 지지부에서 소성변형을 확인하였다. 북미 법규의 탱크 펑크시험 해석결과 국내 탱크화차는 두부 충돌모드에서 충돌차량의 운동에너지를 4 % 이상 흡수시 두부의 코너부에서 탱크 외벽의 파괴가 발생하였으며, 측면 충돌모드에서 운동에너지 30 % 이상 흡수시에 충격체가 접촉하는 탱크 외벽의 파괴가 발생하여 내부 적재물의 누출을 예상하였다. 국내 유류 운송용 탱크화차의 해외 충돌안전 기준의 만족을 위해서는 차체 구조보강 설계 및 탱크 방호설계 수준을 향상시킬 필요가 있다.

• 환경영향평가
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• 제26권6호
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• pp.563-573
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• 2017

매년 화력발전소에서 약 800톤이상 되는 석탄재가 발생되고 있다. 발생되는 석탄재 중 재활용되고 남은 석탄재는 회처리장에 매립되고 있다. 현재 회처리장 용량에는 한계가 있고, 석탄재 매립으로 인한 환경영향의 우려로 회처리장 신규 확보도 어려운 상황이다. 환경영향 최소화라는 측면에서 석탄재 재활용 및 유효이용이 향후 장기적 국가적으로 시급하게 해결해야 할 문제로 인식되고 있다. 따라서, 본 연구는 국내 석탄재 재활용 확대를 가로막고 있는 문제점을 분석하여 해외 사례를 바탕으로 친환경적 국토관리와 자원순환사회를 위한 석탄재 재활용 확대 방안을 제안 하고자 하였다. 국내 석탄재 재활용 확대 방안은 다음과 같다. 첫째, 석탄재를 재활용 할 수 있는 법적 근거를 마련하는 것이다. 이를 위해서는 환경성 예측 평가에 대한 기법과 기준 및 체계 개발이 필요하다. 둘째, 이해관계자들의 인식 전환을 유도하는 것이다. 석탄재의 환경 안전성에 대한 연구 및 홍보가 필요하며 이해관계자들의 적극적인 의사소통 및 정보 제공이 필요하다. 셋째, 석탄재 재활용을 활성화 할 수 있는 실제적인 지원방안이 필요하다. 정책방안으로는 석탄재 처리비 지원, 석탄재 공급센터 설치 등이 있다.