• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.162-168
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• 2009

This thesis is based on the research and experiment of the optimal efficiency generation of electric power. The research and experiment were conducted to search the optimal generation of electric power from a specific amount of solar energy from Photovoltaic Power System with a solar position tracker were used. The changes in the array angles and spacing of the PV Module were also taken into account as well. Here are the findings and the conclusions. First of all, based on experiment using the various anglers, the efficiency generation of electric power increased to a maximum of approximately $12{\sim}17$[%] more at the PV module inclination angle of 30[$^{\circ}$] than at the inclination angles of 20[$^{\circ}$] and 40[$^{\circ}$]. As a result, we have found that installing the PV module inclination at the angle of 30[$^{\circ}$] brought about the most efficient conversion effect of the Photovoltaic Power System. But, when the solar cell is installed on a roof or rooftop where snow builds up, it is the most appropriate to install the solar energy at an 35[$^{\circ}$] angle so that snow slides down and not build up on the module.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.3
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• pp.369-375
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• 2010

Since multi-view images can be utilized for 3D visualization and surveying as well, a system calibration is an essential procedure. The cameras in the system are mounted to the holder and their locations and attitudes are relatively fixed. Therefore, the locations and the attitudes of the perspective centers of the four oblique looking cameras can be calculated using the location and attitude of the nadir looking camera and the boresight values between the cameras. In this regard, this research is focusing on the analysis of the relative location and attitude between the nadir and oblique looking cameras based on the results of the exterior orientation parameters after the aerial triangulation of the real multiview images. We acquired high standard deviations of the relative locations between the nadir and oblique cameras. Standard deviations of the relative attitudes between the cameras were low when only the exterior orientations of the oblique looking cameras were allowed to be adjusted. Moreover, low standard deviations of the relative attitudes came when we considered not all the exterior orientations of the cameras but the attitudes of them only.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.134-138
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• 2021

Various types of precision plastic thin films are used widely in high-performance displays, such as smartphones. For plastic thin-films manufactured by the Roll-to-Roll process, the film thickness must be measured and managed while moving. In the Roll-to-Roll process, wrinkles are generated when tension is applied to the film, which causes an inclination on the optical axis of the thickness gauge, resulting in a loss of accuracy. Therefore, this study attempted to develop an optical interference tomography measurement system. In this study, the tilt angle of the film was measured to correct the measurement value error in the thickness gauge caused by the tilt of the film. The system was constructed so that the laser was irradiated on the tilted film, and the laser reflected from the film was formed on the PSD. The relationship between the tilt angle of the film and the output value of the PSD was obtained experimentally. Using this, a device to measure the tilt angle of the film was constructed, and angle measurements were taken at a speed of 250,000Hz.

• Journal of the Korean Geotechnical Society
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• v.39 no.11
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• pp.41-51
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• 2023

This study employs three-dimensional simulation through FLAC3D to investigate the impact of installation angles on the dynamic characteristics of Triaxial Micropiles. The numerical model is validated against centrifuge test results to ensure accuracy. The findings reveal significant influences of the installation angle on the dynamic behavior of Triaxial Micropiles. Specifically, under seismic conditions such as the Capetown and San Fernando earthquakes, the lowest recorded values for peak bending moment and settlement occurred at an installation angle of 15 degrees. In contrast, when subjected to an artificial earthquake with a frequency of 2 Hz (Sine 2 Hz), Micropiles installed at 0 degrees exhibited the lowest peak bending moment, maximum axial load, and settlement values.

• Journal of Environmental Impact Assessment
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• v.31 no.1
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• pp.75-81
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• 2022

The purpose of this study is to propose the angle-limit of the escape ramp by analyzing the frog behavior characteristics according to the inclination angle of the waterway escape ramp installed in the concrete U-bench plume pipe channel. Forthe experiment, an escape test device was manufactured with the same shape and number of materials applied in the field. And Rana coreana living in paddy wetlands were sel selected. The main behaviors of frogs on the slope were 'jumping', 'crawling' and 'slipping', and afterrecording the behavioralresults according to the inclination angle, statistical analysis was conducted using the chi-square test method. As a result of the analysis, there was no statistically significant difference between 30° and 40°. This result is an evidence for expanding the standard of inclination angle 30° suggested in the 'Guidelines for Installation and Management of Ecological Pathways' to a maximum of 40°. However, further research is required in that the escape ramp targets not only Korean frogs but also various small wild animals. However, considering that various wild animals are affected by artificial canals, additional studies using various target wild animals are needed.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.5
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• pp.10-18
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• 2019

In this study, flow characteristics and the starting pressure of a center body diffuser (CBD) were analyzed at various center body (CB) positions and cone angles. According to the CB position, the location of oblique shock moved to the front from behind the CB cone with an increase in the flow momentum. Additionally, when a strong oblique shock occurred, the direction of supersonic flow was affected and induced to diffuser wall. As a function of different cone angles for the oblique shock, the starting pressure of the CBD was significantly affected.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.559-564
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• 2004

최근들어 광범위한 지역의 삼차원 국토정보 취득을 위한 고해상도 위성영상의 센서모형화 기법에 관한 연구가 활발히 진행되고 있다. IKONOS나 SPOT 5호와 같은 고해상도 위성영상의 모형화에 앞서 본 연구에서는 각종 응용분야에서 광범위하게 활용되고 있는 SPOT 3호 위성영상을 대상으로 지상기준점을 이용하여 경사촬영(off-nadir viewing)각을 추정하는 기법을 개발하였다. 추정된 경사촬영각은 영상좌표를 보정하는데 사용되었으며 2차원 부등각사상변환을 이용하여 기존의 모형화 방법 보다 간결하고 정확도가 향상된 모형화 기법을 제안하였다. 또한, 기존의 엄밀 센서 모형화 방법을 대체하고 있는 위성영상의 센서모형화를 위한 다양한 방법들이 제안되고 있기 때문에, 2차원 부등각사상변환, 직접선형변환(DLT), 자체검정-DLT(SDLT)등의 추상화된 모형화 방법을 SPOT 위성영상에 대해 기준점 수의 변화에 따라 검사점을 이용하여 수평성분, 수직성분으로 나누어 정확도를 비교 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.65-70
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• 2018

본 연구에서는 2차원 수치모형을 통해 보의 설치 각도 변화에 대한 보 상하류에서 흐름특성 변화와 하도 변화를 정량적으로 분석하였다. 수치모의 결과, 흐름은 경사형보를 월류하면서 경사진 방향으로 굴절되었으며, 보의 설치 각도가 증가할수록 흐름의 굴절 각도가 증가하는 경향을 보였다. 또한 보의 설치 각도가 증가할수록 무차원유속은 감소하였다. 보의 보 상류에서는 보의 의해 형성된 배수의 영향이 끝나는 지점에서 유사가 퇴적되어 델타가 발달하였다. 델타는 흐름방향을 따라 하류로 이동하였다. 이동속도는 보에 가까워질수록 감소하며, 크기는 증가하였다. 보 하류에서는 무차원 보의 길이가 증가함에 따라, 무차원 사주의 파장이 감소하고, 무차원 사주의 파고는 증가하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.5
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• pp.187-192
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• 2011

Tilt angle of r-plane wafer is a one of the important factors related with the quality of the GaN epi, so the fine control of the tilt angle is important for the growing of high quality non-polar a-GaN epi. We prepared the R-plane sapphire wafers with slight tilt angles for nonpolar a-plane GaN. The target tilt angles of ${\alpha}$ and ${\beta}$ were 0, -0.1, -0.15, -0.2, -0.4, $-0.6^{\circ}$ and -0.1, 0, $0.1^{\circ}$, respectively. The tilt angles of sliced R-plane sapphire wafers were measured by x-ray and the statistical evaluation of reliability of tilt angles of wafers were performed. The tolerance of the tilt angle was ${\pm}0.03^{\circ}$. R-plane sapphire wafers have relatively large distributions of BOW and TTV data than c-plane sapphire wafers due to the large anisotropy of R-plane. As the tilt angle ${\alpha}$ was increased from -0.1 to $-0.6^{\circ}$, the step widths and heights were decreased from 156 nm to 26 nm and 0.4 nm to 0.2 nm, respectively. The growth and qualities of GaN epi seems to be largely affected by the change of step structure of R-plane sapphire wafers with tilt angle.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.351-361
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• 2012

The leading surgical method for correcting the misalignment of the varus and valgus in the knee joint is the high tibial osteotomy (HTO). In the opening wedge HTO (OWHTO), there is no concern about damaging the peroneal nerve on the lateral tibia of the proximal fibula. OWHTO has been the preferred choice, as the opening of the correction angle can be modulated during the operation. The correction of the varus and valgus on the coronal plane are performed adroitly. Nevertheless, there have been numerous reports of unintended changes in the medial tibial plateau and posterior slope angle (PSA). The authors have developed an HTO method using computer-assisted surgery with the aim of addressing the abovementioned problems from an engineer's perspective. CT images of the high tibia were reconstructed three-dimensionally, and a virtual osteotomy was performed on a computer. In addition, this study recommends a surgical method that does not cause changes in the PSA after OWHTO. The results of the study are expected to suggest a clear relationship between the anteromedial cortex oblique angle of each patient and the PSA, and an optimal PSA selection method for individuals.