• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.3 s.357
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• pp.6-11
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• 2007

This paper proposes CMOS optical receivers to reduce effective area and pulse width distortion (PWD) in high definition digital audio interfaces. To mitigate effective area and PWD, proposed receivers include a frans-impedance amplifier (TIA) with dual output and a level shifter with threshold convergence, respectively. Proposed circuits are fabricated using $0.25{\mu}m$ CMOS process and measured result demonstrated the effective area of $270\times120{\mu}m^2$ and PWD of ${\pm}3%$ for the receiver with a dual output TIA, and the effective area of $410\times140{\mu}m^2$ and PWD of ${\pm}2%$ for the receiver with a threshold convergence level shifter.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.493-498
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• 1998

CdTe films were deposited by close spaced sublimation with various substrate temperatures, cell areas, and thicknesses of CdTe and ITO layers and their effects on the CdS/CdTe solar cells were investigated. The resistivity of CdTe layers employed in this study was 3$\times$ $10^{4}$$\Omega$cm For constant substrate temperature the optimum substrate ternperature for CdTe deposition was $600^{\circ}C$. To obtain larger grain size and more compact microstructure, CdTe film was initially deposited at 62$0^{\circ}C$, and then deposited at 54$0^{\circ}C$. The CdTe film was annealed at 62$0^{\circ}C$ and $600^{\circ}C$ sequentially to maintain the CdTe film quality. The photovoitaic cell efficiency improved by the "two-wave" process. For constant substrate temperature, the optimum thickness for CdTe was 5-6$\mu m$. Above 6$\mu m$ CdTe thickness, the bulk resistance of CdTe film degraded the cell performance. As the cell area increased the $V_{oc}$ remained almost constant, while $J_{sc}$ and FF strongly decreased because of the increase of lateral resistance of the ITO layer. The optimum thickness of the ITa layer in this study was 300~450nm. In this experiment we obtained the efficiency of 9.4% in the O.5cm' cells. The series resistance of the cell should be further reduced to increase the fill factor and improve the efficiency.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.169-171
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• 2008

마이켈슨 간섭계 시스템에 두 개의 Convex Lens를 추가함으로서 평면파 참조광을 유지 시키며, 물체에 조사되는 물체광의 조사면적을 변화시킬 수 있는 새로운 형태의 마이켈슨 간섭계를 제작 하였다. 새로운 형태의 마이켈슨 간섭계를 반사형 디지털 홀로그래피 현미경 시스템(Digital Holography Microscope System)에 적용하여 촬상소자(CCD: Charge Couple Device)에 홀로그램 기록 시 기록 가능한 CCD의 유효 영역과 재생 가능 영역에 대해 연구를 하였다

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.328-332
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• 2004

본 연구에서는 자연하천유역에 적합한 저류상수 산정공식을 개발하기 위하여 섬진강 유역에 대한 유역특성인자 및 강우특성인자를 분석하고, 이의 단계별 회귀분석으로부터 유역면적, 하도연장, 하도경사의 유역특성인자뿐만 아니라 강우특성인자인 유효강우강도를 설명변수로 갖는 저류상수 산정공식을 개발하였다. 그리고 개발된 공식의 적용성을 검토하고자 Clark의 단위도 모형에 기존의 경험공식 및 본 인구에서 개발된 공식을 이용하여 섬진강 유역의 실제 호우사상에 대한 유출수문곡선을 분석하여 관측수문곡선과 비교 검토한 겉과, 본 연구에서 개발된 공식에 의한 유출수문곡선이 관측치에 가장 적합하였다. 또한, 남한강의 지류인 섬강 유역에 대한 빈도별 설계강우량을 적용하여 저류상수 및 설계홍수량을 산정하고 기존에 분석된 저류상수 및 홍수량과 비교 검토한 결과 빈도별 유효강우강도의 변화를 고려한 저류상수의 적용 가능성 및 그 타당성을 확인할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.400-400
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• 2018

우리나라는 현재 17,310개소(2015년)의 저수지가 존재하고 있으며, 지자체가 13,916개소, 한국농어촌공사가 3,394개소를 관리하고 있다. 이중 30만㎥ 이상인 저수지가 전체 저수량의 대부분을 차지하기 때문에 1,500개소에 대해서는 저수위 등이 계측되고 있고, 그 외에 소규모 수리시설물의 경우 유역면적, 만수면적, 총저수량, 유효저수용량, 제원 등 현황만 관리되고 있다. 그러나 미계측 되는 10만$m^3$ 미만 소규모 수리시설물(15,175개소)의 총저수량은 약 2.5억$m^3$으로 전체의 4.2%에 불과 하지만, 수혜면적 32.9만ha로 전체의 약 65.9%를 차지하고 있어 소규모 수리시설물의 저수량을 파악할 필요가 있다. 미계측 수리시설물의 저수량 측정은 수문계측기를 이용하는 방법이 가장 정확한 방법이나 비용이 과다하게 소요되는 측면이 있어 전국 저수지에 설치하는 것은 현실적으로 불가능하기에 미계측 수리시설물의 저수면적-저수량 관계식을 개발하여 저수량을 도출하고자 한다. 미계측 수리시설물 저수량 산정은 저수지의 지리적 위치, 저수지의 형태(삼각, 사각, 원형 등), 총 저수량 등에 따라 단면 형태를 추정하여 구분한다. 저수면적-저수량 관계식을 형태별로 제시하여 실제 계측이 이루어지고 있는 자료와의 비교 검토를 통해 관계식을 검증하고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.280-287
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• 1997

This study was carried out to investigate agricultural status and soil fertility of Bonghwang-cheon watershed area which is located at Chodong-myeon, Milyang-si. The acreage of arable land was about 1,209ha, and the population was 3,706 people. Out of total arable land, paddy was 64.4%, upland 19.6% and orchard 16.0%. Chicken was the largest in the number of livestock and poultry, but pig seems to contribute most severly to water pollution. The geology in the lower stream was alluvium but andesite and derivated materials from it were occupied most upland areas. Tuff was scattered in the small area near by the alluvium of Nakdong river, and diorite and granodiorite were located at the low hill and mountains respectivately. The principal paddy soils in the area were Geumgog, Jisan and Imgog series etc of fine loamy on sloped valleys and fans. The Pyeongtaeg series, fine silty family of imperfectly drained on plain was irrigated by Chodong reservoir. The clayey Honam series on alluvium was distributed along the low hill while Gyuam series, coarse silty alluvial soil way close to Nakdong river. In chemical properties of soils, the vinyl house soils were higher in EC, and orchard soils in OM, $P_2O_5$, exchangeable canons than other soils.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.135-142
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• 2020

In the recent farming industry, there is a growing diffusion of drones, which are recognized as a crucial technology of the 4 th industrial revolution to cope with aging. Especially, filming and pest control using drones are representative fields that have different age groups for obtaining a national license of multicopter that is a ultra-light flying device, and can create profits after getting a license. However, pest control technology using drones has different spray effects depending on levels of operational proficiency, since this highly relies on an operator's operating skills. It is anticipated that if this issue is supplemented, the use of drones for pest control in the farming industry will diversify. For analysis of spraying characteristics of agricultural pest control drones, this study aims to formulate effective spraying hours and effective spraying intervals and suggest an algorithm, which facilitates an accurate calculation of pest control area depending on the kinds of pest control drones. This algorithm can be used in the field of pest control by improving scatterling issues caused by drone flight methods of drone pest controllers and building an optimum pest control manual in future.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.327-331
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• 2010

충남 당진에 위치한 1,200만$m^2$의 석문 국가산업단지의 개발에 따라 용수수요는 $5m^3/m^2$/년를 적용하면 6,000만$m^3$/년 정도 예상된다. 충남 서북부의 다른 산업단지에서 요구되는 용수수요로 물 확보가 크게 대두되고 있으며, 석문 담수호가 조성돼 있지만 수질관리와 용수를 위해 자체유역에 추가로 수원을 확보할 필요가 있다. 석문 담수호는 유효저수량 910만 $m^3$, 총저수량 1,461만 $m^3$, 만수위 EL.-1.70 m, 사수위 EL.-3.00 m, 수혜면적 1,546 ha, 유역면적 $252.2km^2$이며, 당진읍의 인구 4만 6천명의 생활용수 회귀수와 유역의 농업용수 회귀수를 고려하여 유입량을 모의하고 담수호의 일별 저수량 변화를 분석한 결과 공업용수를 연간 3,500만 $m^3$ 공급할 수 있으며 2,500만 $m^3$이 부족한 것으로 분석되었다. 또한 상류에 유효저수량 937만 $m^3$, 총저수량 972만 $m^3$, 만수위 EL.86.90 m, 사수위 EL.64.60 m, 수혜면적 1,293.8 ha, 유역면적 $25.9km^2$인 고풍 저수지가 위치하고 있으며, 증고에 의해 총저수량을 1,946만 $m^3$로 증가시켜도 석문 담수호의 용수공급능력은 거의 증가되지 않는 것으로 분석되었다. 고풍저수지의 유역배율이 2배 정도가 돼, 증고에 의한 하류 하천 유량은 거의 증가되지 않는 것으로 분석되었으며, 고풍저수지를 이용한 석문 자체유역의 수원확보는 타당하지 않은 것으로 밝혀졌다. 따라서 다른 수원확보를 위한 면밀한 검토가 절실히 요구된다.

• Journal of Sensor Science and Technology
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• v.10 no.4
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• pp.214-221
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• 2001

The use of an asymmetric Mach-Zehnder interferometric amplitude modulator to measure a relatively low frequency electric field strength is described. The sensitivity of an electric field sensor using a $Ti:LiMbO_3$ optical modulator is strongly affected by the shape of a electrode(probe antenna). To measure the low frequency electric field, a probe antenna of wide effective area is more useful than the usual dipole antenna. As a proof of this, the optical modulator was fabricated with a plate-type probe antenna and the usefulness of this antenna tested for measuring low frequency electric field strength. Measurements were performed in the range 0.1 V/cm to 60 V/cm at 60Hz through 100 kHz. Using a probe antenna of $10\;mm{\times}10\;mm$, the output voltage of $10^{-2}\;mV$ was measured with respect to the electric field strength of 0.1 V/cm at 60 Hz. By increasing the effective area of the probe antenna, better sensitivity is obtainable over the measured range.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.113-116
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• 2008

In recent the construction of bridges having hollow sectional piers is gradually increasing since the hollow section is more effective than solid section in resistance against seismic load. It is, therefore, very important to understand the behavior of columns with hollow sections in seismic design. However, many past researches were concentrated only on the flexural deformability of them. In this study the shear characteristics of them have been studied with scale model tests. 7 models having different void and aspect ratios were designed and tested to investigate the effect of them on shear capacities. And then the validity of empirical equations to predict shear capacity was investigated compared with the test results. The test result 80 percent of the valid area of cross section should be adequate. And compared to the proposed four model the experimental shear capacities are in good agreement with the UCB.