• 한국농공학회지
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• 제32권4호
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• pp.27-43
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• 1990

This study aimed at developing a generalized model on the estimation of the long - term run - off volume for practical purpose. During the research period of last 3 years( 1986-1988), 3 types of estimation model on the long - term run - off volume(Effective rainfall model, unit hydrograph model and barne's model for dry season) had been developed by the author. In this study, through regressional analysis between determinant factors (bi of effective rainfall model, ai of unit hydrograph model and Wi of barne's model) and catchment characteris- tics(catchment area, distance round the catchment area, massing degree coefficient, river - exte- nsion, river - slope, river - density, infiltration of Watershed) of 11 test case areas by multiple regressional method, a new methodology on the derivation of determinant factors from catchment characteristics in the watershed areas having no hydrological station was developed. Therefore, in the resulting step, estimation equations on run - off volume for practical purpose of which input facor is only rainfall were developed. In the next stage, the derived equations were applied on the Kang - and Namgye - river catchment areas for checking of their goodness. The test results were as follows ; 1. In Kang - river area, average relative estimation errors of 72 hydrographs and of continuous daily run - off volume for 245 days( 1/5/1982 - 31/12) were calculated as 6.09%, 9.58% respectively. 2. In Namgye - river area, average relative estimation errors of 65 hydrographs and of conti- nuous daily run - off volume for 2fl days(5/4/1980-31/12) were 5.68%, 10.5% respectively. In both cases, relative estimation error was averaged as 7.96%, and so, the methodology in this study might be hetter organized than Kaziyama's formula when comparing with the relative error of the latter, 24~54%. However, two case studies cannot be the base materials enough for the full generalization of the model. So, in the future studies, many test case studies of this model should he carries out in the various catchment areas for making its generalization.

• 한국항만학회지
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• 제15권1호
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• pp.57-74
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• 2001

In the past, the predictions of beach processes and harbor sedimentation were mainly relied on the hydraulic model tests and empirical methods. In recent years, however, as computers have come into wide use, more accurate models have gradually been developed and thus replaced those conventional methods. For prediction of topographical change near the coastal area, we need informations of wave and current conditions in the numerical model which should be calculated in advance. Numerical model introduced in this study combines wave refraction-diffraction, breaking, bottom friction, lateral mixing, and critical shear stress and three sub-models for simulating waves, currents, and bottom change were briefly discussed. Simulations of beach processes and harbor sedimentation were also described at the coast neighboring Bangpo Harbor, Anmyundo, Chungnam, where the area has suffered accumulation of drifting sand in a small fishing harbor with a wide tidal range. We also made model test for the new layout of the harbor and planned south breakwater for preventing intrusion of sand. Although the model study gave reasonable description of beach processes and harbor sedimentation mechanism, it is necessary to collect lots of field observation data, including waves, tides and bottom materials, etc. for better prediction.

• 융복합기술연구소 논문집
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• 제2권2호
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• pp.40-48
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• 2012

A small domestic desiccant dehumidifier is modelled using effectiveness models for a desiccant wheel and a wet-air condenser. The desiccant wheel and condenser models are used to compose a system model in the form of a set of simultaneous linear algebraic equations, which is solved by Gauss method. The system model is used to simulate the behaviour of a dehumidifier with a 1kW electric air heater. It is found that the maximu COP is about 0.5 and dehumidification capacity is 18kg/day when the ratio of dehumidification area is 0.7. The optimum wheel thickness and face velocity are found 100mm and 1.5m/s, respectively.

• 한국지리정보학회지
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• 제7권1호
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• pp.28-38
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• 2004

본 연구는 수치지형자료의 해상도와 보간법의 변화에 따른 정확도 분석을 실시하여 도시소유역의 유출현상을 해석하고자 하였다. 수치자료는 격자크기별로 TIN 보간법을 이용하여 DEM 자료를 생성하고, 정확도 분석은 수치지도의 등고선을 이용하여 결정계수($R^2$)와 회귀식을 도출하였다. 검증된 DEM 자료를 사용하여 소유역구분, 면적, 유역폭, 지면경사도 등의 지형인자를 추출하여 도시유출모형에 적용시켜 여서-문수지구의 도시 소유역에 가장 적합한 유출모형을 알아보고자 한다. 모형의 적용 결과 SWMM의 유출수문곡선이 ILLUDAS의 유출수문곡선보다 실측값에 더 근사하게 나타났고, SWMM의 경우 실측값과 최대 19%, 최소 5%, 평균 13%의 오차를 나타냈다. 본 연구대상지역과 같은 도시소유역은 강우지속시간이 첨두도달시간에 미치는 영향은 미미하게 나타났다. 본 연구의 결과로 SWMM 모형이 여서-문수지역의 도시유출모형으로 적합하며 적용면에서도 더 다양한 기능과 정확성을 나타낸다고 판단된다.

• 대한지리학회지
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• 제48권6호
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• pp.978-993
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• 2013

공간회귀모형은 공간가중행렬을 통해 공간관계를 명시적으로 정량화한다는 점에서 타 모형과 뚜렷하게 구별되는 강점이 있는 동시에, 공간가중행렬 구성에 자의성이 개입된다는 약점을 가지고 있기도 하다. 본 연구에서는 공간가중행렬의 구성에 따라 모형 적합도가 어떻게 변화하는지 인천시를 사례로 실증적으로 검토하였다. 또한 인근지역 범위 설정에 따라 공간시차모형(spatial lag model) 또는 공간오차모형(spatial error model) 중 어떠한 모형이 보다 우수하게 나타는지 검토하였다. 분석 결과, 토지가격 추정에 있어 인근지역 범위를 좁게 파악하는 공간가중행렬을 구성할수록 모형 적합도가 전반적으로 개선되는 것이 확인되었다. 또한, 공간적 이질성이 심한 지역은 공간오차모형의 적합도가 보다 우수한 것으로 파악되었다. 공간적 이질성이 심한 지역은 동질적 성격을 갖는 하부 인근지역으로 세분함으로써 그러한 이질성을 완화시킬 수 있었고, 그 결과 공간오차모형보다 공간시차모형의 적합도가 우수하게 나타날 수 있음을 밝혔다.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.949-958
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• 2024

In contrast to all-time flooded small modular reactor (SMR) systems, an in-kind flooding safety system (FSS) has been proposed as a passive safety system applicable to small modular reactors (SMRs) that adopt a metal containment vessel (MCV). Under transient conditions, the FSS can provide emergency cooling to dry reactor cavities and sustain long-term coolability using re-acquired evaporated steam in the reactor building on demand. When designing an FSS, the effect of the flooding flow area is vital as it affects the overall accident sequence and safety. Therefore, in this study, a MELCOR model of a reference SMR is developed and numerical analysis is performed under postulated accident scenarios. Without flooding, the MCV pressure of the reactor module exceeds the design pressure before core damage. To prevent core damage, an emergency flooding strategy is devised using various flow path parameters and requirements to ensure an adequate emergency coolant supply before the core damage is investigated. The results indicate that a flow area exceeding 0.02 m2 is required in the FSS to prevent MCV overpressure and core damage. This study is the first to report a strategic analysis for appropriately sizing an FSS flooding valve applicable to innovative SMRs.

• 응용통계연구
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• 제21권5호
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• pp.855-866
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• 2008

최근 격자자료(lattice data) 분석 방법을 이용한 소지역 추정(small area estimation)이 연구되고 있으며 좋은 결과를 주고 있는 것으로 알려져 있다. 소지역 추정에 주로 사용되는 격자자료(lattice data) 분석의 경우 가장 자료를 잘 설명할 수 있는 이웃정보시스템을 사용하여야 분석의 효율을 향상시킨 수 있다. 최근 이강석과 신기일 (2008)은 지리정보시스템을 이용하여 만들어진 여러 이웃정보시스템을 비교, 분석하였다. 본 논문에서는 이강석과 신기일(2008)이 제안한 여러 이웃정보시스템이 소지역 추정에 얼마나 영향을 미치는지를 MSE, 커버리지, 캘리브레이션 그리고 회귀분석 방법 등을 이용하여 비교하였다. 2001년 경제활동인구조사의 실업자수 자료가 비교에 사용되었다.

• 한국통신학회논문지
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• 제29권5A호
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• pp.554-565
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• 2004

본 논문에서는 단일 클락 사이클과 다중 클락 사이클에 수행되는 여러 가산기를 구현하고 area와 time을 비교한다. 가산기의 크기를 64, 128, 256-비트로 다양화 시키면서, 특히 하이브리드 구조의 가산기는 소그룹을 4, 8, 16-비트로 나누어서 group / ungroup으로 합성을 하여 비교하였다. 제안된 가산기들은 Verilog-HDL을 이용하여 하향식 설계 방법으로 구현되었다. Cadence의 Verilog-XL.을 이용하여 설계된 가산기와 behavioral model을 이용한 가산기의 출력이 일치하는지를 비교하여 검증하였다. 검증된 모델은 삼성 0.35um 3.3(V) CMOS standard cell 라이브러리를 이용하여 합성되었으며, 최악 조건 2.7(V), 85($^{\circ}C$)에서 동작하였다. 스마트 카드 IC의 Crypto-Processor에 사용할 수 있는 최적화된 가산기는 64-비트를 기준으로 할 때, group으로 합성된 16-비트 캐리 예측 가산기를 기반으로 하는 리플 캐리 가산기(RCA_CLA)이다. 이 가산기는 198(MHz)의 속도로 동작하며, 게이트 수는 nand2 게이트 기준으로 약 967개이다.

• 대기
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• 제25권1호
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• pp.67-83
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• 2015

Predicting the location and intensity of precipitation still remains a main issue in numerical weather prediction (NWP). Resolution is a very important component of precipitation forecasts in NWP. Compared with a lower resolution model, a higher resolution model can predict small scale (i.e., storm scale) precipitation and depict convection structures more precisely. In addition, an ensemble technique can be used to improve the precipitation forecast because it can estimate uncertainties associated with forecasts. Therefore, NWP using both a higher resolution model and ensemble technique is expected to represent inherent uncertainties of convective scale motion better and lead to improved forecasts. In this study, the limited area ensemble prediction system for the convective-scale (i.e., high resolution) operational Unified Model (UM) in Korea Meteorological Administration (KMA) was developed and evaluated for the ensemble forecasts during August 2012. The model domain covers the limited area over the Korean Peninsula. The high resolution limited area ensemble prediction system developed showed good skill in predicting precipitation, wind, and temperature at the surface as well as meteorological variables at 500 and 850 hPa. To investigate which combination of horizontal resolution and ensemble member is most skillful, the system was run with three different horizontal resolutions (1.5, 2, and 3 km) and ensemble members (8, 12, and 16), and the forecasts from the experiments were evaluated. To assess the quantitative precipitation forecast (QPF) skill of the system, the precipitation forecasts for two heavy rainfall cases during the study period were analyzed using the Fractions Skill Score (FSS) and Probability Matching (PM) method. The PM method was effective in representing the intensity of precipitation and the FSS was effective in verifying the precipitation forecast for the high resolution limited area ensemble prediction system in KMA.

• 한국환경과학회지
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• 제12권6호
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• pp.615-626
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• 2003

The applied model for this study area is WINFLOW using mite element method, It is thought that the simulation result by WINFLOW model under the steady flow state reflects well the ground water distribution within the reliability level which shows the error range of 1.1% to 8.0% from the comparison between the computed values and the observed, and analyzed that the constant head distribution is shown along the east-west direction and gentle and stable head gradient along the north-south direction. Ground water of the study area shows stable movement from the south to the stream area, and the particle trace for each location shows relatively linear shape from the upstream to the pumping location while the radius of influence according to the pumping amount shows a significant difference at the down stream area from the pumping location. The simultaneous pumping from P and P1 shows more complicated appearance, not the increase of the radius of influence than pumping from a single well P or P1, and it is analyzed that the particle path takes nearly linear form. It is known that the flow direction of the ground water and the velocity of the flow affect on the magnitude of the radius of influence of the wells from the fact that the more decreasing pattern of the ground water head is observed at the side of the well and the down stream area than the upstream area when the ground water moves from south to north regarding the radius of influence according to the pumping amount. Satisfactory results in analyses of ground water movement are obtained through the significant reduction of the physical uncertainties in the flow system as well as the relatively convenient model application using WINFLOW model which is proposed in this study.