• Journal of Korean Port Research
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• v.8 no.1
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• pp.17-22
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• 1994

The wave interaction with flexible membrane such as PVC and fabrics is studied to prove its applicability to portable breakwaters. To obtain the wave exciting force acting on flexible membrane, eigen-function expansion method is employed. The effect of flexible is involved in body boundary condition in which x-directional displacement of membrane is obtained by solving the linear membrane equation. Displacement of membrane is assumed to be small compared to wavelength, therefore the tensile force of membrane remains constant. As the numerical examples, transmission and reflection coefficients according to the change of tensile forces are investigated. The hydrodynamic force on membrane, the dynamic tension in the mooring lines and the vertical displacement profile of membrane are also calculated. It is suggested that the flexible membrane can be used to engineering material for the future coastal/ocean applications.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.486-489
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• 2020

본 설계는 얼굴과 눈을 인식한 후, 시선추적을 통해 마우스와 눈동자의 움직임을 연결하여 메뉴를 주문하는 기술이다. 시선추적을 통해 키오스크를 터치하지 않아도 메뉴를 간편하게 주문할 수 있고, 얼굴인식을 이용해 자신의 최근 주문기록을 확인하여 쉽고 빠르게 메뉴를 주문할 수 있다. 얼굴이 등록되어있지 않은 새로운 사용자는 안드로이드 앱을 이용하여 사진과 메뉴를 선택하여 장바구니에 담아 주문 시간을 단축할 수 있어 바쁜 현대인들에게 편리함을 제공할 수 있도록 구현하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.169-170
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• 2008

가전 기기제어를 위해서 통상적으로 리모컨을 사용하지만 집안에 넘쳐나는 리모콘 때문에 불편한 점이 있다. 본 논문에서는 URC 처럼 하나의 리모콘으로 사용할 착용형 시스템을 소개하고, 여러 개의 가전기기를 음성, 제스처 등과 같은 다양한 모달리티들을 이용하여 동일한 방법으로 제어 할 수 있는 방법을 제안하고 시스템을 소개한다.

• New & Renewable Energy
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• v.20 no.1
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• pp.52-60
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• 2024

This study conducted an economic analysis of renewable heat energy by estimating the levelized cost of heat production (LCOH) of ST and GSHP and comparing it with the cost of alternative fuels. The LCOH of ST ranged from 396.8 KRW/kWh to 578.7 KRW/kWh (small-scale), 270.3 KRW/kWh to 393.3 KRW/kWh (large-scale), and 156.3 KRW/kWh to 220.7 KRW/kWh for GSHP. The economic feasibility of ST and GSHP was analyzed by comparing the calculated LCOH and the fuel costs such as gas and kerosene prices. Moreover, scenario analyses were conducted for installation subsidies under the current system to examine the changes in the economics of renewable thermal energy.

• Journal of Soil and Groundwater Environment
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• v.10 no.6
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• pp.75-80
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• 2005

Several metalliferous including Guedo mine, Manjung mine and Joil mine located at the upper watershed of Namhan river, were abandoned or closed since 1988 due to the mining industry promotion policy and thus disposed an enormous amount of mining wastes without a proper treatment facilities, resulting in soil pollution. In this research, total and fractional concentrations of heavy metals in mining wastes were analyzed and accordingly the degree of soil pollutions in the abandoned mine area were quantitatively assessed employing the several pollution indices. 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 mining activities. Index of geoaccumulation 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, $4\~6,\;0\~6,\;4\~5$, 2 and 0 respectively. The index of geoaccumulation of Cd, Pb, Zn and Cu reveals the mining wastes has high pollution potential in the area. According to sequential extraction of metals in the mine wastes 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.

• (The)Study of the Eastern Classic
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• no.41
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• pp.187-209
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• 2010

This thesis to be studied conversation by writing between the medical staff of Chosun(朝鮮) and Japan in 1763. Both countries the medical staff and intellectuals meet that communication, confrontation and conflict, exchanges and cooperation in 18C. They met greeting and sing in chorus. Chosun keep checking in western medicine of Japan. They are compared to customs of two countries. Also Japanese increase interest in the Hangeul(한글). Confrontation and conflict resulted from history recognition and difference of viewpoint of two countries. Especially Kokugaku(古學) have many influence on this situation. So battle come and go to study of Ogyu Sorai(荻生?徠) and Dajai Jun(太宰純). But this situation includes Mutual misunderstanding. Because of limitation on conversation by writing. Exchanges and cooperation take shape on the medical staff that a process of ginseng(人蔘), medical treatment. And two countries promote goodwill that method of buying books in Japan and medical treatment. In conclusion, intellectuals of Chosun and Japan have some misunderstanding and distrust. but they are communication with Chinese writing that east asian's common language. Also exchange its views and information.

• Journal of Ocean Engineering and Technology
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• v.28 no.5
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• pp.474-483
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• 2014

The majority of existing WECs (wave energy converters) are designed to achieve maximum power at a resonance condition. In the case of a single WEC, its size must be large enough for tuning, and it has high efficiency only within a limited frequency band. Recently, wave power extraction by deploying many small buoys in a compact array has been studied under the assumption that the buoy's size and separation distance are much smaller than the water depth, wave length, and size of the array. A boundary value problem involving the macro-scale boundary condition on the mean surface covered by an infinite strip of buoys is solved using the eigenfunction expansion method. The energy extraction efficiency (${\varepsilon}=1-R^2_f-T^2_r$), where $R_f$ and $T_r$ are the reflection and transmission coefficients for a strip array of buoys, is assessed for various combinations of packing ratio, strip width, and PTO damping coefficient.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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• pp.208-218
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• 2017

The performance of a wave energy converter (WEC) that uses the rolling motion of a partially submerged pendulum plate in front of a quay wall was analyzed. The wave exciting moment and hydrodynamic moment were obtained using a matched eigenfunction expansion method (MEEM) based on the linear potential theory, and then the roll motion response of a pendulum plate, time averaged extracted power, and efficiency were investigated. The optimal PTO damping coefficient was suggested to give the optimal extracted power. The peak value of the optimal extracted power occurs at the resonant frequency. The resonant peak and its width increase as the submergence depth of the pendulum plate decreases and thickness of the pendulum plate increases. An increase in the wave incidence angle reduces the efficiency of the wave energy converter. In addition, the WEC using a rolling pendulum plate contributes not only to the extraction of the wave energy, but also to a reduction in the waves reflected from the quay wall, which helps to stabilize ships going near the quay wall.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.157-162
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• 2004

Constructed wetlands are considered as an important tool for wastewater treatment, wastewater management and flooding control. In addition, one of the most promising technologies for application in many countries seems to be constructed wetlands, due to their properties such as utilization of natural processes, simple construction, operation and maintenance, process stability, cost effectiveness, etc. This study considered possibility of treatment of livestock wastewater using a constructed wetland. The removal efficiencies of $COD_{cr}$, TOC, TN, TP, SS, and color were 97.6%, 96.6%, 97.0%, 96.7%, 99.0%, and 85.6%, respectively. In particular, SS was completely removed. However, $Cl^{-}$ concentration of the constructed wetland effluent was higher than that in influent. In conclusion, constructed wetlands could be applied to livestock wastewater treatment if $Cl^{-}$ would be properly treated. Further, it needs time for stabilization to reduce the pollutants which were accumulated in soil.

• Journal of Environmental Science International
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• v.15 no.2
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• pp.133-139
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• 2006

Soil biofiltration is an environmentally-sound technology for elimination of VOCs, odorous and NOx compounds from a low concentration, high volume waste gas streams because of its simplicity and cost-effectiveness. This study was performed to evaluate effect of removal of gaseous NOx using a soil and a yellow soil. Over $60\%\;and\;48\%$ of NOx from a soil and a yellow soil was removed at the inlet NO concentrations of $423\~451$ppb, respectively. The bio-filter using a soil media was capable of purifying NOx with a different natural processes. Although some of the processes are quite complex, they can broadly be summarized as adsorption into soil pore water, and biochemical transformations by soil bacteria. When the filteration bio-reactor was applied to a soil and a yellow soil, effective NOx removal was obtained for several times and months. These results show that a soil biofilter can be of use as an alternative advanced NOx treatment system.