• Journal of Korea Water Resources Association
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• v.37 no.9
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• pp.695-706
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• 2004

This study is to propose the temporal pattern of design rainfall which causes maximum peak discharge, and to analyze the relation of catchment characteristics and critical durations for gauged midsize catchment. Hydrologic analysis has done over the 44 midsize catchments with 50-5,000$\textrm{km}^2$. The type of temporal pattern of design rainfall which causes maximum peak discharge has resulted in Huff's 4 quartile distribution method for effective rainfall(AMC III) The peak discharges of 24hr rainfall duration are similar to those of critical duration for 50-600$\textrm{km}^2$, and the peak discharges of 48hr rainfall duration are similar to those of critical duration for 600-5,000$\textrm{km}^2$. Therefore, if the proper rainfall intensity formula is selected, 24hr or 48hr rainfall duration may be regarded as the critical duration of midsize catchment. A simple regression equation is derived by using a catchment area and critical duration with high correlation for the case of effective rainfall(AMC III). Therefore, it can be used to determine the critical duration of ungauged catchment with 50-5,000$\textrm{km}^2$. Also, dimensionless regression equation is derived by using characteristic values of unit hydrograph.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.1-9
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• 2009

In this paper, a small area 12-bit 300MSPS CMOS Digital-to-Analog Converter(DAC) is proposed for display systems. The architecture of the DAC is based on a current steering 6+6 segmented type, which reduces non-linearity error and other secondary effects. In order to improve the linearity and glitch noise, an analog current cell using monitoring bias circuit is designed. For the purpose of reducing chip area and power dissipation, furthermore, a noble self-clocked switching logic is proposed. To verify the performance, it is fabricated with $0.13{\mu}m$ thick-gate 1-poly 6-metal N-well Samsung CMOS technology. The effective chip area is $0.26mm^2$ ($510{\mu}m{\times}510{\mu}m$) with 100mW power consumption. The measured INL (Integrated Non Linearity) and DNL (Differential Non Linearity) are within ${\pm}3LSB$ and ${\pm}1LSB$, respectively. The measured SFDR is about 70dB, when the input frequency is 15MHz at 300MHz clock frequency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.657-665
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• 2017

The aim of this study was to develop and distribute a dedicated program that can easily calculate the effective dose of a patient undergoing nuclear medicine examinations, and assist in the study of dose of nuclear medicine examinations and information disclosure. The program produced a database of the effective dose per unit activity administered (mSv/MBq) of the radiopharmaceuticals listed in ICRP 80, 106 Report and the fourth addendum, was designed through Microsoft Visual Basic (In Excel) to take the effect of 5 different (Area, Clark, Solomon(=Fried), Webster, Young) of pediatric dose calculation methods and 7 different body surface area calculation methods. The program calculates the effective dose (mSv) when the age, radionuclide, substance, and amount injected in the human body is inputted. In pediatric cases, when the age is entered, the pediatric method is activated and the pediatric method to be applied can be selected. When the BSA (Body Surface Area) formula is selected in the pediatric calculation method, a selection window for selecting the body surface area calculation method is activated. When the adult dose is input, the infant dose and the effective dose (mSv) are calculated automatically. The patient effective dose calculation program of the nuclear medicine examinations produced in this study is meaningful as a tool for calculating the internal exposure dose of the human body that is most likely to be obtained in nuclear medicine examinations, even though it is not the actual measurement dose. In the future, to increase the utilization of the program, it will be produced as an application that can be used in mobile devices, so that the public can access it easily.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.95-104
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• 1999

Comparative biodegradation studies of liquid and solid alkanes and of two different solid alkanes were conducted by an isolated Acinetobacter sp., which degraded crude oil alkanes simultaneously. for the determination of degradation mechanism of hydrophobic crude oil constituents. Also a model oil experimental system composed of a solid alkane. heneicosane, as a substrate and a non-degradable non-aqueous phase liquid. pristane, as an oil matrix was established and studied. It was proposed that the Acinefobacter sp. utilized hydrophobic substrates directly on the surface of them with no difference in the degradation rates between the liquid and solid alkanes. On the basis of the results from the heneicosane/pristane system which imitates crude oil matrix containing solid constituents. the crude oil matrix was considered to reduce the bioavailability of contained substrates by reducing the specific surface area of substrates to contact with microorganisms.

• Journal of IKEEE
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• v.17 no.3
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• pp.275-283
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• 2013

In this paper, a 8bit 10Ms/s CMOS Folding and Interpolation analog-to-digital convertor is proposed. The architecture of the proposed ADC is based on a Folding & Interpolation using FR(Folding Rate)=8, NFB(Number of Folding Block)=4, IR(Interpolation Rate)=8. The proposed ADC adopts a preamplifier sharing method to decrease the number of preamplifier by half comparing to the conventional ones. This chip has been fabricated with a 0.35[um] CMOS technology. The effective chip area is $1.8[mm]{\times}2.11[mm]$ and it consumes 20[mA] at 3.3 power supply with 10[MHz] clock. The INL is -0.57, +0.61 [LSB] and DNL is -0.4, +0.51 [LSB]. The SFDR is 48.9[dB] and SNDR is 47.9[dB](ENOB 7.6b) when the input frequency is 100[kHz] at 10[MHz] conversion rate.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.246-252
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• 1998

A survey was conducted to investigate the status of soils involving pH, electrical conductivity, total organic matter content, available phosphate and major exchangeable cations in the paddy soils sampled from 1,168 sites throughout the country. The content of soil chemical properties was lower on the average than the optimum levels for cropping. An average value showed pH 5.6, organic matter $25g\;kg^{-1}$, available phosphate $128mg\;kg^{-1}$, available silicate $72mg\;kg^{-1}$, and exchangeable potassium and the calcium and magnesium were 0.32, 4.0, $1.2cmol^+\;kg^{-1}$, respectively. Soil chemical properties was related with topography except soil pH. A soil pH and organic matter, available phosphate, exchangeable potassium increased with time while exchangeable calcium, magnesium available silicate decreased with time.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.8
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• pp.47-55
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• 2010

In this paper, a timing register architecture using demultiplexer and counter is proposed to reduce the area of the high resolution SAR type analog to digital converter. The area and digital power consumption of the conventional timing register based on the shift register is drastically increased, as the resolution is increased. On the other hand, the proposed architecture results in reduction of the area and the power consumption of the error correction logic of the SAR ADC. This chip is implemented with 0.18 um CMOS process. The area is reduced by 5.4 times and the digital power consumption is minimized compared with the conventional one. The 12 bits SAR ADC shows ENOB of 11 bits, power consumption of 2 mW, and conversion speed of 1 MSPS. The die area is $1 mm{\times}1mm$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.433-442
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• 2017

This study consists of five case studies of the catering facilities of newly-built elementary schools' in Sejong City, regarding the spatial configuration and allocation. The analysis indicated that the space allocated in the cooking area in the five schools compared to the standard was as follows: School A; 99.2%, B; 91.1%, C; 81.4%, D; 110.8%, E; 88.1%. Accordingly, the cooking area was close to, or slightly above the standard; nevertheless, other areas in the facilities were not allocated sufficient space and were not appropriately planned. Among the other findings, the receiving areas of three schools were not even planned, and the receiving works were carried out in the pre-preparation area. Considering the flow of the dish-washing process, the width of the room should be at least 3.6 meters with a passage width of 1.6 meters, and easy access to the cooking and dining areas must be equipped. An interview with all five supervisors showed that most complaints focused on the cooking and dishwashing areas, whereas there were none in the storage and workers' area. The result highlights the importance of the cooking and dishwashing areas as the main functions in catering facilities, and future planning strategies should consider this aspect.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.825-830
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• 2007

사면에서 발생되는 강우유출과정에 기여하는 대공극의 영향은 그 중요성에도 불구하고 잘 알려져 있지 않다. 특히 대공극의 공간적분포특상에 대한 현장측정은 이뤄지지 않았다. 본 연구의 실험지역은 경기도 포천시 광릉수목원에 있는 작은 소유역이다. 이 지역의 정밀한 측량을 하여 수치고도모형(DEM)을 얻었다. 이 수치고도모형을 바탕으로 수치지형분석을 통해 흐름선을 파악하여 총 20지점을 선정하였다. 각 지점에서의 대공극을 통한 수직적인 유동들은 장력침투계를 사용하여 지표면아래 깊이 10cm에서 측정하였다. 공간적 토양의 특성분포를 파악하기 위해 각 지점에서의 체적밀도와 점토함량을 조사하였다. 토양수분의 공간적 분포 특성은 TDR(Time Domain Reflectometry)방식인 TRASE를 이용하여 토양수분 값을 얻었다. 이러한 다양한 공간적 특성들은 대공극발달의 공간적 분포특성을 파악하는 중요자료가 된다. 소유역을 크게 기여사면 면적을 기준으로 상부, 중부, 하부로 나누어 대공극의 유효 공극율과 대공극흐름율을 계산하였다. 상부에서의 유효 대공극율의 평균값과 변동계수는 각각 4.3%, 42.1%이고, 대공극흐름율의 평균값과 변동계수는 각각 45.0%, 26.6%이다. 중부에서는 유효 대공극율의 평균값과 변동계수는 6.8%, 37.3%이고, 대공극흐름율의 평균값과 변동계수는 56.2%, 14.4% 이다. 그리고 하부에서의 유효공극율의 평균값과 변동계수는 12.5%, 58.3% 이고 대공극흐름율의 평균값과 변동계수는 64.5%, 24%이다. 이는 유효 대공극율과 대공극흐름율의 비율은 기여사면 면적이 증가할수록 증가하였다. 이는 대공극을 통한 물 이송 능력이 원두부로 갈수록 증가한다는 것을 보여주고 있다.e, taurine, methionine, phenylalanine은 함량(含量)이 적었다. 5. 일건(日乾)중 총유리아미노산의 변화(變化)는 생시료(生試料)의 경우 2,041.2 mg%였으나 1일(日) 건조(乾燥) 후는 1,784.0 mg%로 감소(減少)하다가 그 이후 계속 증가(增加)하여 20일(日) 건조(乾燥) 후는 5,277.0 mg%였다. 6. 일건(日乾)중 leucine, isoleucine, valine은 대체로 증가(增加)하는 경향(傾向)을 나타내었으나 aspartic acid, proline, taurine은 대체로 감소(減少)하는 경향(傾向)을 나타내었다. 436.59mg%로 가장 많았고 군유산(軍有山) 차엽(茶葉)이 146.94mg%로 가장 적었으며 일반차엽(一般茶葉)의 평균치(平均値)는 264.59mg%, 용장(龍欌) 차엽(茶葉)이 223.10mg%, Yabukita 차엽(茶葉)이 256.49mg%였다. 7) 이상(以上)의 결과(結果)를 종합(綜合)할 때 용장(龍欌) 차엽(茶葉)은 일반차엽(一般茶葉)과 형질(形質) 뿐만 아니라, 성분(成分)도 다르므로 품종(品種)이 다른 수종(樹種)으로 추정(推定)되며 와운(臥雲) 차엽(茶葉)은 일반차엽(一般茶葉)과 형질(形質)은 다르나 성분상(成分上)의 비슷한 점으로 보아 동일계통(同一系統)의 변이(變異)된 대엽종(大葉種)으로 추정(推定)된다.5(${\pm}0.77$0.77) % 의 오차로 크게 감소하였다. 결론: 방사선이 통과하는 경로에 불균질조직인 폐가 존재할 경우에도 불균질조직에 대하여 조직의 밀도를 이용하여 보정하는 방법을 사용하여 투과선량으로부터 종양선량을 계산할 수 있음을 알 수 있었다.X>로 평균$43.26{\m

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.310-320
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• 2009

In this paper, we estimate area-averaged solution of peening residual stress using a 3-D multi-impact symmetry-cell FE model. The symmetry-cell model includes factors reflecting peening phenomena and plastic shot. Area-averaged solution is much closer to XRD experimental solution than 4-node-averaged solution in plastic shot FE model. We then obtain FE Almen saturation curve corresponding to experimental Almen curve based on area-averaged solution. Using the curve, we obtain FE area-averaged solution in major peening materials, and compare the FE solution with experimental solution. In peening materials, surface, maximum compressive residual stress and deformation depth reach experimental solutions. Thus, FE Almen curve is useful for estimation of residual stress solution and could improve the efficiency of peening process. Consequently, it is confirmed that concept of area-averaged solution is the realistic analytical method for evaluation of peening residual stress.