• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.468-470
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• 2007

This paper is to present an approach for generating coarse resolution (MODIS data) fraction images of forested region in Korea peninsula using forest type area fraction derived from high resolution data (ASTER data) in regional forest area. A 15-m spatial resolution multi-spectral ASTER image was acquired under clear sky conditions on September 22, 2003 over the forested area near Seoul, Korea and was used to select each end-member that represent a pure reflectance of component of forest such as different forest, bare soil and water. The area fraction of selected each end-member and a 500-m spatial resolution MODIS reflectance product covering study area was applied to a linear mixture inversion model for calculating the fraction image of forest component across the South Korea. We found that the area fraction values of each end-member observed from high resolution image data could be used to separate forest cover in low resolution image data.

• 태양에너지
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• 제4권2호
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• pp.37-42
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• 1984

A computer code for an optimum design of solar space and domestic hot water heating system has been developed. The f-chart method developed by S.A. Klein et al. has been incorporated in the present computer code. The main conclusions obtained from the present work may be summarized as follows: (1) In Seoul area, about 46% of the total heating load can be obtained from the solar collectors whose total surface area is about one-third of the total heating floor area. (2) In Pusan area, total area of solar collectors should be about half of the total heating floor area in order to obtain an equivalent solar fraction of Seoul. (3) In cheju area, on the other hand, only about 42% of the total heating floor area of solar collectors is needed to get the same solar fraction as in Seoul and Pusan. (4) In order to get the first 50% solar fraction, only about 10-14 collectors ($4'{\times}8'$ collectors) are required, whereas about 48 collectors are needed to obtain the solar fraction of 100%. That is, roughly 3.5-4.5 times greater number of collectors are required to increase the solar fraction from 50% to 100%. Therefore, it can be concluded that it is relatively inefficient and less economical to build a solar system whose solar fraction exceeds more than 50%.

• 한국해양공학회지
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• 제6권2호
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• pp.35-40
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• 1992

A recently developed new technique for measuring the fraction of wetted area has applied to pool boiling of water. The basis of the new applied technique of ultrasonic makes use of the reflection of ultrasonic from the vapour surface to measure the fraction of wetted area values. The results are the measured fraction of wetted area values in nucleate and transition boiling and the pool boiling curve for water under steady state conditions. The measurement of this paper shows a fraction of wetted areaf around 0.98 at the critical heat flux for water.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.374-381
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• 2001

Surface roughness plays a significant role in friction, wear, and lubrication in machine components. Most engineering surfaces have tile nogaussian height distrubution. So, in this study, elastic-plastic contact simulations are conducted for not only gaussian surfaces but also nongaussian surfaces. Nongaussian rough surface considering the kurtosis is generated numerically. The contact simulation model takes into account the plastic deformation behaviors of asperities by setting a celing on their contact pressure at material hardness value. It will be shown that the performace variables such as real contact area fraction, plastic area fraction and average gap are sensitive to the characteristics of surface geometry according to kurtosis.

• 대기
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• 제29권4호
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• pp.381-390
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• 2019

This study investigates the impacts of urban land-use fraction and temperature advection on the urban heat island intensity over the Seoul metropolitan area using the UM (Unified Model) with the MORUSES (Met Office Reading Urban Surface Exchange Scheme) during the heat wave over the region from 2 to 8, August 2016. Two simulations are performed with two different land-use type, the urban (urban simulation) and the urban surfaces replaced with grass (rural simulation), in order to calculate the urban heat island intensity defined as the 1.5-m temperature difference between the urban and the rural simulations. The land-use type for the urban simulation is obtained from Korea Ministry of Environment (2007) land-use data after it is converted into the types used in the UM. It is found that the urban heat island intensity over high urban-fraction regions in the metropolitan area is as large as 1℃ in daytime and 3.2℃ in nighttime, i.e., the effects of urban heat island is much larger for night than day. It is also found that the magnitude of urban heat island intensity increases linearly with urban land-use fraction. Spatially, the estimated the urban heat island intensities are systematically larger in the downwind regions of the metropolitan area than in the upwind area due to the effects of temperature advection. Results of this study indicate that urban surface fraction in the city area and temperature advection play a key role in determining the spatial distribution and magnitude of urban heat island intensity.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.363-370
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• 2005

There are approximately 2,000 metallic mines which have been abandoned in Korea. Most of the mines are located in the watershed area, which is main source of drinking water for Seoul Metropolitan area. Untreated mining wastes are remained around abandoned mines in study area. These mining wastes, flowing into farmland and stream in the downstream of abandoned mines, would cause water and soil pollution. The mining waste samples from Guedo mine, Manjung mine and Joil mine recently abandoned were collected for the evaluation of the potential of water pollution by mine waste. Index of geoaccumulation($M\"{u}ller$, 1979), fractional composition and removal efficiency of some heavy metals by different concentration of HCl treatment were analyzed. Index of geoaccumulation of Cd, Pb, Zn, Cu, Ni and Cr are 6, $4{\sim}6,\;0{\sim}6,\;4{\sim}5$, 2 and 0 respectively. Index of geoaccumulation of Cd, Pb, Zn and Cu reveals the mining wastes has high pollution pottential in the area. Organic fraction of Cu, reducible fraction of Pb, residual fraction of Ni and Zn were the most abundant fraction of heavy metals in mining wastes.

• 동의생리병리학회지
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• 제16권5호
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• pp.893-898
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• 2002

Citri Reticulatae Viride Pericarpium extract(CRVP) have been used in oriental medicine for many centuries as a therapeutic agent for smoothing the liver and regulating the circulation of qi, and promoting digestion and removing stagnated food. The effects of CRVP on the inhibition of brain damage in cerebral ischemia is not known. Therefore, this Study was designed to investigate the cerebral protective effects of CRVP on the transient cerebral ischemia using modern techniques, and further to provide the possibility of scientification of oriental medicine. The size of cerebral infarct size was measured by morphometry, and brain edema was measured by morphometry and brain water content determination. The results were a$ follows ; 1. Water fraction of CRVP was reduced infect area of rats brain slices which were subjected to a transient cerebral ischemia in a dose-dependent manner. 2. Methylene chloride fraction and hexane fraction of CRVP was significantly reduced infarct area of rats brain slices which were subjected to a transient cerebral ischemia in a dose-dependent manner. 3. Methylene chloride fraction and hexane fraction of CRVP was significantly reduced infarct volume of rats brain which was subjected to a transient cerebral ischemia in a dose-dependent manner. 4. Methylene Chloride fraction and hexane fraction of CRVP was significantly decreased brain edema induced by a transient cerebral ischemia in a dose-dependent manner. 5. Methylene chloride fraction and hexane fraction of CRVP was significantly decreased brain water content of rats which were subjected to a transient cerebral ischemia. It is suggested that CRVP has an anti-ischemic effect through the inhibition of brain damage in a transient cerebral ischemia, and that in future further development of main effective constituent in CRVP can provide a novel therapeutic strategy for cerebral ischemia.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.59-67
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• 2012

In this paper, performances of solar hot water supply systems are parametrically analyzed with the variations of solar collector area, slope of collector and volume of storage. All simulations are conducted by using TRNSYS computer program. Average solar fractions, collector efficiencies and temperatures of storage are investigated monthly as well as annually. For system analysis, the maximum value of monthly average solar fractions has a limitation of 90 percent. As a result, the designed solar thermal system with $6m^2$ collector area, $50^{\circ}$ slope and $0.36m^2$ storage volume could provide almost an annual average solar fraction of 72 percent. By increasing the storage volume to $0.42m^2$, the annual solar fraction of system increases up to 73 percent.

• 한국정밀공학회지
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• 제18권10호
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• pp.53-60
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• 2001

Surface roughness plays a significant role in friction, wear, and lubrication in machine components. Most engineering surfaces have the nongaussian height distribution. So, in this study, contact simulations are conducted for not only gaussian surfaces but also nongaussian surfaces. Nongaussian rough surface considering the kurtosis is generated numerically And the effects of kurtosis on real contact area fraction, average gap, and mean asperity contact pressure are studied. It will be shown that the real contact area fraction and the mean asperity contact pressure are sensitive to the characteristics of surface geometry according to kurtosis.

• 한국초등수학교육학회지
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• 제13권1호
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• pp.115-140
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• 2009

Freudenthal은 수학화를 핵심 개념으로 하는 현실주의 수학 교육론을 주창하였다. 수학화란 현실 안에 있는 여러 현상들을 수학적인 수단을 사용하여 조직함으로써 현실에 질서를 부여하는 활동을 말한다. 본 연구에서는 Freudenthal의 수학화 이론을 바탕으로 제 7차 초등 수학 교과서 5-가 단계의 넓이 단원을 재구성하여 실험적인 지도만을 작성한 다음, 이를 통하여 교수 실험을 실시함으로써, 수학화를 통한 넓이의 지도 방안의 효과와 더불어 학생들의 넓이 개념과 공식에 대한 이해 실태를 분석하였다. 그 결과, 넓이의 개념 이해 측면에서는 실험반 학생들이 우수하였으나, 넓이의 계산 측면에서는 유의미한 차이가 없는 것으로 나타났다.