• Earthquakes and Structures
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• 제9권1호
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• pp.173-194
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• 2015

Site response analysis is an important topic in earthquake engineering. A time-domain numerical method called as one-dimensional (1D) finite element artificial boundary method is proposed to simulate the homogeneous plane elastic wave propagation in a layered half space subjected to the obliquely incident plane body wave. In this method, an exact artificial boundary condition combining the absorbing boundary condition with the inputting boundary condition is developed to model the wave absorption and input effects of the truncated half space under layer system. The spatially two-dimensional (2D) problem consisting of the layer system with the artificial boundary condition is transformed equivalently into a 1D one along the vertical direction according to Snell's law. The resulting 1D problem is solved by the finite element method with a new explicit time integration algorithm. The 1D finite element artificial boundary method is verified by analyzing two engineering sites in time domain and by comparing with the frequency-domain transfer matrix method with fast Fourier transform.

• Wind and Structures
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• 제20권3호
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• pp.469-488
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• 2015

A full-scale instrumented low-rise building with gable roof was built at a coastal site with a high incidence of tropical cyclones for monitoring of wind effects on the building during windstorms. This paper presents the field measurements of the wind velocity field around and the wind-induced pressures on the low-rise building during the passage of severe tropical storm Soudelor. Near-ground wind characteristics such as wind speed, wind direction, turbulence intensity, gust factor, turbulence integral length scale and wind velocity spectra were investigated. The wind-induced pressures on the roof of the building were analyzed and discussed. The results revealed that the eave and ridge edges on the roof were subjected to the most severe suction pressures under quartering winds. These suction pressures showed obvious non-Gaussian behavior. The measured results were compared with the provisions of ASCE 7-10 to assess the suitability of the code of practice for the wind-resistant design of low-rise buildings under tropical cyclones. The field study aims to provide useful information that can enhance our understanding of the extreme wind effects on low-rise buildings in an effort to reduce tropical cyclone wind damages to residential buildings.

• 한국광학회지
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• 제13권2호
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• pp.166-170
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• 2002

본 연구에서 우리는 반사형 LCD용 반사판을 최적화하고자 한다. 반사판의 새로운 표면구조를 체계적인 수식적 접근 및 분석을 통해 구한 후, 반사특성의 결과를 바탕으로 기존의 표면구조와 비교해서 보다 최적화된 표면구조를 제시하고자 한다. 반사특성의 결과로는 새로운 표면구조가 기존의 표면구조에 비해 동일한 시야각 범위에서 보다 균일한 반사율 분포를 나타내고 있으며, 또한 주변환경을 충분히 고려해서 사용자 위주의 자유로운 시야각 범위 조절이 가능함을 알 수 있다. 결과적으로, 새로운 표면구조는 보다 균일한 반사율 분포를 가지게 됨으로써, 기존의 반사형 LCD의 시야각 의존성을 상당부분 개선할 수 있으리라 본다.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.88-92
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• 2020

As a highly conductive and transparent electrode, the optical transmittances of ITO/Ag/ITO were simulated and compared with the experimental results. The simulations are based on the finite-difference time-domain (FDTD) method in solving linear Maxwell equations. In our simulations, the computation domain is set in the XZ-plane with 3D dimension, and a plane wave with variable wavelengths ranging from 250 nm to 850 nm is incident in the z-direction at normal incidence to the ITO/Ag/ITO film surrounded by free-air space. As the results through both simulations and experiments, it was shown that the thickness combinations by the ITO layers of about 40 nm and the Ag layer of about 10 nm could be most suitable conditions as a high conductive transparent electrode having the transmittance similar to that of a single ITO layer.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.177-186
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• 2011

We can expect reduction of the sunlight absorption quantity to a structure and an earth surface, a decline of the surface temperature and a decline of the heat transport volume in what there is a method I give the sunlight reflectance in the aspect to the surface of the building by painting sunlight high reflectance paint, and to reduce the sunlight absorption quantity to a structure and an earth surface and does so, and, in addition, a method high water retentivity of tree planting and the road surface of the city space uses evaporation latent heat of the water by making it, and to restrain a rise in temperature is thought about. and It is thought that I reduce the sunlight absorption quantity to not only the structure but also other structures and attention gathers to the reflexive reflector reflecting in the direction again and it is wide as a marker of a board and the clothing of the traffic sign and is used the incidence energy from a source of light for this reflexive reflector now by there is it and devises surface structure again, and controlling reflection directivity for the sunlight for the purpose of raising night visibility.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.240-241
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• 2019

Construction disasters have more distinctive characteristics than other industrial disasters. Since it is likely that construction disasters will spread to severe accidents, the accident mortality rate is very high compared to the disaster incidence rate. Therefore, the purpose of this study is to compare and analyze the operation status of construction risk assessment by domestic large and medium sized construction companies to prepare improvement direction of risk assessment system. The survey results for safety management experts of construction companies are as follows: Large companies have developed and utilized risk assessment systems in their respective companies, while small and medium construction companies have developed and evaluated risk factors through the Excel program. Rather than performing risk assessment tasks based on historical safety accident data, construction companies have limitations in developing risk factors and preparing solutions with suppliers for each major construction. Therefore, it is necessary to prepare a risk assessment system in the future by analyzing the types of safety accidents, such as the safety accident data of each company as well as the safety accident data.

• 한국컴퓨터정보학회논문지
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• 제15권5호
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• pp.75-81
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• 2010

적응 배열 안테나 시스템은 간섭신호 방향으로 영점을 형성하여 표적신호를 추정한다. 그러나 적응 배열 안테나 시스템에 상관성 간섭신호가 입사된다면 표적신호를 간섭신호로 간주하여 시스템의 성능이 급격히 감소되고, 지향 오차에 민감하여 주빔이 표적신호의 입사방향을 지향하지 못한다. 본 논문에서는 고차제한조건과 지향오차수정방법을 결합하여 빔형성 알고리즘을 제안하였다. 그리고 제안한 알고리즘으로 자유도 손실을 최소화하고 간섭신호와 지향오차를 감소시켰다. 모의실험을 이용하여 제안 알고리즘과 기존 알고리즘의 성능을 비교 분석하였다. 본 논문에서 제안한 알고리즘은 신호 입사각을 정확히 추정하지만 기존의 알고리즘은 약 $0.8^{\circ}$의 오차가 발생하였다.

• 한국음향학회지
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• 제34권2호
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• pp.108-116
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• 2015

수중 음향 벡터센서는 음압 뿐 아니라 음파의 진행 방향에 관한 정보를 측정할 수 있는 센서이다. 본 논문에서는 미세 외팔보를 이용한 수중 음향 벡터 센서를 구현하기 위해 음향학적 이론을 바탕으로 음향과 기계 구조물의 상호작용을 이론적으로 정립하고자 하였다. 감응 방식으로 압전 효과를 이용한 두 가지 유니모프(unimorph)형태의 모델을 제시하였으며, 제시된 모델에 대하여 압전 미세 외팔보의 거동을 집중 질량 모델을 통해 음파가 임의의 주파수와 각도를 가지고 미세 외팔보로 입사할 때 나오는 신호의 크기를 구할 수 있는 전달함수를 유도하였다. 또한 이를 바탕으로 매우 얇고 유연한 구조물로 미세 외팔보를 설계하면 매질의 입자 속도에 관한 정보를 직접적으로 측정 가능한 센서로 활용할 수 있다는 것을 확인하였다.

• 대한안전경영과학회지
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• 제23권3호
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• pp.35-45
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• 2021

Activities to prevent industrial accidents can be divided into management of disaster risk factors of production facilities, disaster prevention systems and procedures, and human factors management. Human factor management is the last and most effective means to minimize disaster incidence and loss costs. The key strategy for this is safety and health education. However, formal or fictitious education is still being carried out in the industrial field. In addition, it is true that the application of practical use is insufficient due to the simple theoretical education based on knowledge transfer. In order to change the safety consciousness of employers and workers, we think that the paradigm of education should be changed from the traditional text and video-oriented lecture education method to experience-oriented education. The purpose of this study is to measure and analyze the effectiveness of safety education through education contents using VR(Virtual Reality) and AR(Augmented Reality) technology in keeping with the changing times of the 4th Industrial Revolution, And to suggest the direction of future safety and health education and content development trend.

• 대한치과의료관리학회지
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• 제9권1호
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• pp.1-6
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• 2021

Measuring and quantifying the burden of disease (BoD) is crucial for healthcare policy-related decisions. For this purpose, summary measures of population health (SMPH) have been proposed to overcome the limitations of prevalence, incidence, and mortality. Oral health remains separated from the mainstream healthcare system, and the lack of reliable epidemiological data has been pointed out as the cause. In this study, we aimed to understand the flow of international and domestic BoD research related to oral disorders and the direction in which those studies should advance in the future. It is necessary to continuously revise the previously measured BoD of oral disorders and calculate the BoD by performing subdivisions, starting from the development of lay descriptions. Furthermore, developing elaborate BoD measurement methodologies that reflect the complexity of the oral cavity is essential.