• 한국측량학회지
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• 제27권3호
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• pp.347-356
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• 2009

최근 산업계를 비롯한 다양한 분야에서 대상물에 대한 3차원 측정과 형상화에 대한 요구가 급증함에 따라 측정 및 3차원 모델링을 위한 3차원 레이저스캐닝 시스템의 활용이 급증하고 있다. 그러나 3차원 레이저 스캐닝 시스템의 역할 및 활용의 증가하고 있는데 반해 스캔에 의해 획득되는 결과에는 다양한 원인에 의한 오차가 포함됨으로 인하여 고정밀 측정이 요구되는 분야에서 활용에 부분적인 제약으로 작용하고 있다. 이에 본 연구에서는 레이저측정방식을 채용하고 있는 3차원 레이저스캐닝 시스템을 이용하여 오차발생의 가장 큰 요인으로 조사되고 있는 측정대상을 표면물질의 반사율에 따른 오차발생특성과 발생비율을 분석함으로써 3차원 스캔자료의 정확도 향상을 꾀하고자 하였다. 연구결과, 측정대상물의 표면물질에 따라 반사량이 다르게 나타남을 확인할 수 있었으며, 표면반사율과 레이저파의 반사량 사이에 비례관계가 성립되는 특성을 확인할 수 있었다.

• The Korean Journal of Ecology
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• 제25권1호
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• pp.45-49
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• 2002

Pollen analyses and $^{14}$ C dating of the sediments of the Akindonuma moor, which is situated in a closed depression of an old landslide, were peformed in order to study the vegetation history of the montane zone of the Miyagi Prefecture, Northeast Japan. The main results are as follows: Two forest zones have been distinguished: 1) the A-I zone, or the Fagus-Quercus-Betula forest (R I stage, before about 11,700 yrs B.P.), and 2) the A-II zone, or the Fagus-Quercus forest (R II stage, after about 11,700 yrs B.P.). By comparing the geological section with the pollen diagram of the moor, it is assumed that the deposit environment of the Middle Part, which mostly consists of peat layers, is very stable. During the period, the Ulmus/Zelfkova pollen ratio was very low and small peak was not recognized. According to the preceding research, theme is a close relationship between the fluctuation of the Ulmus/Zelkova pollen ratio and the general trend of hillslope instability in the changing balance of temporature and precipitation Actually, Zelkova serrata tends to cover the footslope and the lower sideslope. Ulmus davidiana covers the footslope and the alluvial cone. Therefore, the fact that the Ulmus/Zeikova pollen ratio was very low and small peak was not recognized, is believed to reflect the stability of the earth's surface environment, which was estimated from the geological section.

• Geomechanics and Engineering
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• 제31권1호
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• pp.71-86
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• 2022

In Taiwan, an efficient approach for enhancing the stability of colluvium slopes is the drilled shaft method. For slopes with drilled shafts, the soil arching effect is one of the primary factors influencing slope stability and intertwines to the failure mechanism of the pile-soil system. In this study, the contribution of soil arching effect to slope stability is evaluated using the FEM software (Plaxis 3D) with the built-in strength reduction technique. The result indicates the depth of the failure surface is influenced by the S/D ratio (the distance to the diameter of piles), which can reflect the contribution of the soil arching effect to soil stability. When α (rock inclination angles)=β (slope angles) is considered and the S/D ratio=4, the failure surface of the slope is not significantly influenced by the piles. Overall, the soil arching effect is more significant on α=β, especially for the steep slopes. Additionally, the soil arching effect has been included in the proposed stability charts. The proposed charts were validated through two case studies, including that of the well-known Woo-Wan-Chai field in Taiwan. The differences in safety factor (FoS) values between the referenced literature and this study was approximately 4.9%.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제22권1호
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• pp.29-37
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• 2016

Purpose: Since the end of the 1990s the question of detecting blind and vision-impaired persons' tactile walking surface indicators have been rasied, the study of detecting tactile walking surface indicators has been started in Japan, German, and Sweden. Through the study, Japan, German, Sweden, and international's standard was revised. The Korean standard of tactile walking surface indicators was revised in 2013, the remarkable point was missed. Therefore, this study suggested deriving a range of types and dimensions of tactile walking surface indicators reasonable, and presenting the design principles for the development of new tactile walking surface indicators though domestic and international literature review. Method: This study was proceeded by comparison analysis of results from various tactile walking surface indicators' literature review from Japan, German, and Sweden, the most suitable range of types and dimensions was abstracted. Then, the range of types and dimensions was compared to the international standards and international reference standard, the ground rules were confirmed to apply new tactile walking surface indicators design. Results: Rationally, the wide and diameter of projecting line and projecting point should be downsized in order to improve detecting blind and vision-impaired persons' tactile walking surface indicators. And with same purpose, the ratio of the wide and diameter of projecting line and projecting point should be decided. The design of the tactile walking surface indicators in addition to the size and spacing of the protrusions should be to reflect the common elements that have been suggested a number of standard criteria. Implication: In this study, the design principles was derived through test results and theoretical studies, and new tactile walking surface indicators would need to be validated in local user.

• Journal of Multimedia Information System
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• 제8권2호
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• pp.93-100
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• 2021

Under the time-varying temperature, the high-temperature radiation of forgings and the change of reflection characteristics of oxide skin on the surface of forgings lead to the difficulty of obtaining images to truly reflect the geometric characteristics of forgings. It is urgent to study the clear and reliable acquisition method of hot forging feature image under time-varying temperature to meet the requirements of visual measurement of hot geometric parameters of forgings. Based on this, this chapter first puts forward the quality evaluation method of forging feature image, which provides guarantee for the accurate evaluation of feature image quality. Furthermore, the factors that affect the image quality, such as the radiation characteristics of forgings and the photographic characteristics of cameras, are analyzed, and the imaging spectrum which can effectively suppress the radiation intensity of forgings is determined. Finally, aiming at the problem that the quality of image acquisition is difficult to guarantee due to the drastic change of radiation intensity of forgings under time-varying temperature, an image acquisition method based on minimum signal-to-noise ratio (SNR) based laser light intensity adaptation is proposed, which significantly improves the definition of feature light strips in forging images at high temperature, and finally realizes the clear acquisition of feature images of large-scale hot forging under time-varying temperature.

• 한국지반공학회논문집
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• 제36권12호
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• pp.117-124
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• 2020

본 연구는 온도에 따른 점성토의 전단 변형의 특성의 모사에 초점을 맞춘다. 일반적으로 온도가 상승할수록 정규압밀선은 간극비와 평균유효응력의 평면에서 하향 이동한다. 하지만 한계상태선은 온도변화에 따라 정규압밀선만큼 이동하지는 않는다. 따라서, 온도가 증가할수록, 한계상태 평균유효응력과 선행압밀 평균유효응력의 차이는 감소한다. 이를 반영하기 위해, 본 연구에서는 한계상태 평균유효응력을 기준으로 두 부분으로 나뉘어진 경계면을 적용하였다. 또한 Bangkok 점성토에 대해서 경계면을 구축하고, 비배수 삼축압축시험에 대해서 요소해석을 실시하였다. 요소해석 결과, 제안된 모델은 복잡한 강성 혹은 발달 법칙 없이 실험 데이터와 유사한 점성토의 온도에 따른 역학적 거동을 잘 모사하였다.

• 한국태양에너지학회 논문집
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• 제31권3호
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• pp.80-88
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• 2011

Heliostat in the tower type solar thermal power plant is a sun tracking mirror system to reflect the solar energy to the receiver and the optical performance of it affects to the efficiency of whole power plant most significantly. Thus a solid understanding of heliostat's energy concentration characteristics is the most important step in designing of the heliostat field and the whole power plant. The work presented here is the analysis of energy concentration characteristics of heliostat used in 200kW solar thermal power plant, where the receiver located at 43m high in tower has $2{\times}2$m rectangular shape. The heliostat reflective surface is formed by 4 of $1{\times}1$m flat plate mirror facet and the mirror facet is mounted on the spherical frame. The direct normal incident radiation models in vernal equinox, summer solstice, autumnal equinox and winter solstice are first derived from the actually measured data. Then the intercept ratio, heat flux distribution and total energy collected at the receiver for the heliostats located in the various places of the heliostat field are investigated. Finally the effect of mirror facet installation error on the optical performance of the heliostat is analyzed.

• 한국환경과학회지
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• 제15권1호
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• pp.45-58
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• 2006

In order to grasp physical characteristics of Ganajin Bay receiving the effluents from land, a comprehensive field surve)'has been conducted at the north of Wando and Gogeumdo in 2002. Water temperature was most high in September while most low in December. A high temperature in September was inferred to have caused by the dispersion of warm fresh water with favor of a dominant wind in autumn. However, salinity and sigma-t in situ was most low in September while most high in December. A low salinity (or density) in September turned out to reflect the influence of a dense rainfall in summer. Water temperature, salinity and density at the surface layer were lower than those at the bottom layer, except for December. Their horizontal profiles suggested the influence of effluents such as Tamjin River. Particularly, time series of water temperature acquired near the sluice and at the north channel of Wando tended to rise at the flood flow but fall at the ebb flow in accordance with the tide. The form ratio of the tide in the study area was $0.31\~0.32$ and the amplitude of the tide appeared to increase towards the west. Northeastward or southwestward flows prevailed in this area but the residual flows were all northeastward with a magnitude of $3\~4cm/s$.

• 한국의류산업학회지
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• 제18권5호
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• pp.695-707
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• 2016

This study presents quantitative evaluation standards for the shape fitness test, conducted in the process of the slacks fit test. This study aims to quantify appearance sensory test of slacks for the objectification of qualitative evaluation methods in existing shape fitness tests. The subjects were women of standard body type between the ages of 18 and 24. Slacks differing in their ease in waist girth, hip girth, crotch length and knee length were designed to test their shape fitness. The gap volume distribution between the body and slack, angle of the baseline by body part, and ratio of total thickness from the sideline using 3D human body scan data (which reflect the results of the appearance sensory test) were presented as quantitative evaluation standards. There were less wrinkles in the wrinkle/overstretch and ease categories of the appearance sensory test; in addition, ease was adequate and small enough to comfortably perform basic human activities in the standing upright posture. The gap volume distribution analysis between body and slacks showed that curves increased in the slacks surface along with an increase of ease in slacks and suggested that wrinkles also increased. In the baseline's horizontal categories in terms of a $0^{\circ}$ horizontal angle, the range of angles were evaluated as adequate by the clothing expert group. The total thickness ratio of 0.5:0.5 divides into the sideline from the baseline.

• 한국방재학회 논문집
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• 제9권2호
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• pp.1-9
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• 2009

물-결합재비 0.4이하의 고성능 콘크리트 수축 변형을 파악하기 위해 전체 수축을 수분의 외부이동에 의한 건조수축과 수분의 내부소모에 의한 자기수축으로 분리한 후, 자기건조에 의한 상대습도 변화와 변형률의 관계를 묘사하기 위하여 계면역학적 접근법에 의한 습도-변형률 관계를 설정하였다. 이에 대한 검증을 위해 자기수축 시험체에서의 습도-수축 측정을 수행하였으며, 기존 연구 모델인 Tazawa, CEB-FIP 모델에 비하여 측정값과 가장 유사한 결과를 나타내어 본 연구에서의 자기수축모델은 자기건조에 따른 자기수축은 선형성을 나타내는 수분의 외부이동에 의한 수축과는 달리 지수적 관계를 갖는 특성과 초기재령에서의 급속한 자기수축 발현 특성을 적절히 묘사하고 있음을 알 수 있었다. 이 후 본 연구의 수분이동-수축 모델을 반영하여 온도, 수분이동, 변형률 해석의 다중물리 모델 해석과 모형시험체 측정을 수행한 결과 매우 유사한 값을 나타내어 본 연구를 통해 측정된 수분의 내부소모에 의한 습도와 수축변형률을 고려한 다중물리모델은 타당할 것으로 판단된다.