• Journal of Korea Water Resources Association
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• v.38 no.2
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• pp.167-177
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• 2005

In this study, the PRMS(Precipitation and Runoff Modeling System), developed by USGS(United States Geological Survey), was applied to the Yongdam dam watershed in the Geum River basin. The efficiency for runoff simulation and spatial characteristics of PRMS were evaluated. The runoff changes with the changes of subcatchments and HRUs were estimated. As results, the size of the subcatchment and HRV did not significantly affect the runoff at the exit of watershed. Consequently, the spatial characteristic of PRMS was shown as lumped type rather than semi-distributed. The geographical input data for Yongdam dam watershed were converted to the USGS Input type, and the parameters were calibrated using Rosenbrock optimization method, validated with the observed runoff data. The PRMS showed resonable agreements in the long-term continuous runoff simulation, if the accuracy of observed data is ensured.

• Journal of Korea Water Resources Association
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• v.35 no.4 s.129
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• pp.411-423
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• 2002

Accurate and real time forecasting of runoff has a high priority in the drainage basins prone to short, high intensity rainfall events causing flash floods. To take into account the resolution of hydrological variables within a drainage basin, use of distributed system models is preferred. The Landsat Thematic Mapper(TM) observations enable detailed information on distribution of land cover and other related factors within a drainage basin and permit the use of distributed system models. This paper describes monitoring technique of rainfall excess by SCS curve number method. The time series maps of rainfall excess were generated for all the storm events to show the spatiotemporal distribution of rainfall excess within study basin. A combination of the time series maps of rainfall excess with a flow routing technique would simulate the flow hydrograph at the drainage basin outlet.

• Journal of Korea Water Resources Association
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• v.32 no.2
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• pp.163-176
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• 1999

Hydrology-based topographical informations generated by GIS techniques could be changed according to the selection of base map, algorithm of extraction, and so on. The purpose of this paper is to investigate the variation of SCS CN extracted by GIS technique and to propose the effective strategy for applying GIS to the rainfall-runoff simulation in ungaged basin. For experimental implementation, GIS spatial data, such as reconnaissance soil map, detailed interpretative soil map, landuse planning map and remotely sensed data(Landsat TM), were collected and generated to calculate the amount of effective rainfall in Pyungchang river basin. In applying SCS Runoff Curve Number to the test basin, the hydrological attribute data were analyzed. In addition, the characteristics of runoff responses according to the selection of GIS spatial data for SCS CN were reviewed. This study shows the applicability of GIS techniques to runoff simulation in ungaged basin by comparing with the measured flood hydrograph. It has been found that the detained interpretative soil map and remote sensing data are appropriate for calculating of SCS CN.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.835-839
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• 2005

일반적으로 분포형 모형에서는 유역을 공간적으로 작은 계산단위로 분할하고, 각 단위에 대해 모형의 이론식을 전개하여 풀이하게 된다. 이 계산단위는 일반적으로 입력자료의 공간적인 해상도보다 크기 때문에 어느 정도 수준까지의 취합을 내포하게 된다. SWAT에서도 수문응답단위 (HRU; Hydrological Response Unit)라는 계산 단위를 통하여 모형 입력 매개변수를 생성하고, 모의를 수행한다. 따라서, 본 연구에서는 SWAT 모형의 거동 특성과 유역별 적정한 수준의 소유역 분할에 대한 기준을 제시할 목적으로 경안천 유역과 보청천 유역을 선정하여, 각 유역변 소유역 수 및 HRU 수에 따른 연평균 유출과 유사의 변화를 검토하였다. 검토 결과, 경안천 유역에 대해서는 SWAT 모형의 적용시에 하천망 생성을 위한 임계면적을 300 ha 이하로 두어 55개 이상의 소유역으로 분할하고, HRU 생성을 위한 토지이용과 토양 면적비는 $8\%$ 이하로 설정하여야 안정적인 유출과 유사 모의가 가능하며, 보청천에 대해서는 임계면적을 5,000 ha 이하로 하여 최소 5개 이상의 소유역으로 분할하고, 토지이용과 토양 면적비는 $1\%$ 이하로 설정하여 HRU를 생성함으로써 안정적인 유출 및 유사 모의가 가능한 것으로 나타났다. 이상의 결과와 같이 적절한 수준의 소유역 분할과 HRU 생성에 대한 기준을 제시함으로써, 모형의 모의 결과의 신뢰도를 크게 감소시키지 않으면서 모형의 입력자료 구축시간과 모형 구동시간을 단축함으로써 모형의 적용 효율을 높일 수 있을 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.4
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• pp.47-57
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• 1983

The parameter of impulse response of groundwater proposed by Kraijenhoff, that is, the reservoir coefficient j is determined on the basis of the least squares criteria. The degree (${\alpha}$) which expresses how much each sequential storm contributes to groundwater flow through the saturated soil is obtained by the optimization techniques which minimize deviations between observed and derived runoff hydrograph, and the convolution summation for the linear theory is used. A numerical example for this study is carried out for a storm event of Goose Creek basin near Leesburg, Virginia. As the results, the groundwater unit hydrograph and baseflow were able to be obtained. The used optimization technique is suited to the purpose of this study in case of the constraints. It is judged that the results allow the determination of baseflow.

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.632-639
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• 2014

In this paper, we propose a PC's self-monitoring system for protecting illegal outflow of important personal files, which are managed in the Windows environment PC. This paper is based on the idea that it should be a read (access) file operation in order to outflow files through the network. To compare the information (name, some content) obtained from all operations of the reading of the 'Windows File System Driver' and captured transmission packets of mini port of 'Windows NDIS (Network Driver Interface Specification) Driver', and, if two pieces of information match, this system will determine the transmission to user. In this paper, tentatively, we developed a function to gather file information about file read operation and developed a function for transmission packet capture. This demonstration implementation showed that the proposed process has validity and the proposed process verified that it does not significantly affect the PC's performance.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1881-1882
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• 2006

표준형 원자력발전소에서는 원자로 내의 핵연료 봉으로부터 발생하는 열에너지를 열교환기인 증기발생기로 전달하는 원자로냉각재 계통이 있다. 핵연료 봉을 적절한 냉각 상태로 유지하기 위하여 원자로냉각재의 온도와 압력뿐만 아니라 체적을 제어하고 있다. 원자로냉각재 체적은 용량이 큰 반면에 제어하는 밸브의 크기는 작아서 제어 응답이 길어서 현장에서 경험적으로 튜닝하는 것은 매우 어렵다. 본 논문에서는 체적제어루프의 수학적인 모델링을 통하여 오프라인으로 최적 제어 파라미터를 찾고, 실제 적용한 결과를 보여준다. 제어루프 모델링을 위하여 일반화 프로세서 모델 식으로부터 실제 운전 데이터로 모델 파라미터를 결정하는 경험적 방법을 사용하였다. 이로부터 구한 제어 파라미터를 실제 적용한 결과, 적절한 제어 응답을 얻었으며 모델링 과정이 적절하였음을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1573-1577
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• 2007

SWAT 모형을 사용하여 수문 및 환경인자들의 예측에 있어서 수문응답단위(Hydrological Response Unit, HRU) 수를 적절하게 결정하는 것은 매우 중요하다. SWAT 모형에서는 수문응답단위라는 계산단위를 통하여 모형의 입력매개변수를 생성하고 모의를 수행하기 때문이다. 본 연구에서는 SWAT모형에서 하천유역의 적절한 HRU 수를 결정하기 위하여 대상유역을 낙동강의 제 1지류이자 국제수문개발계획(International Hydrologic Project, IHP)의 국내 대표유역 중 하나인 위천유역으로 선정하였으며, 토지이용과 토양의 면적비를 조정함으로써 HRU 수를 여러 단계로 적용하여 유출량, 유사량 및 영양염류를 모의하였다. SWAT 모형의 적용을 위하여 위천 유역의 $DEM(30m{\times}30m)$, 토지이용도(1:25,000), 토양도(1:25,000) 등의 GIS 자료와 강우량 및 기상자료를 이용하였다. 본 논문은 위천 유역에 대한 적절한 HRU 수의 기준을 제시하였으며, 이와 같은 분석결과를 이용하여 모형의 입력자료 구축시간을 단축할 수 있어 차후 모형의 적용시에 모형의 적용 효율을 높일 수 있을 것으로 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.2
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• pp.113-117
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• 2015

This study presents a 3-dimensional flow-structure interaction analysis of subsea risers in water flows. Two structural connectors (flat and circular couplers) were intentionally devised and numerically tested using ANSYS CFX to investigate how these couplers behave under the water flows. In the flow analysis, the water field was constructed with an inlet, outlet, and symmetric boundary conditions. As a result, the responses (drag coefficients and pressure fields) were obtained and the pressure fields were applied for the structural analysis. Finally, the structural responses (displacements and equivalent stresses) of the risers were measured to demonstrate the efficiency of the riser connectors.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.69-78
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• 2010

The hydrological-geomorphic character is closely related with runoff in basin. A development of GIS greatly helps investigating about mechanism between theirs. We analyze local slope and hillslope length which are related with hydrological response. But variation of these geomorphic variables has very wide range at each pixel. So there's a limit as to use directly. Therefore we investigate a relation between hydrological response and distributed geomorphic variables according to statistical character of distributed map considering spatial correlation. As a result, the local slope affects peak discharge, and the hillslope length affects peak discharge and time, mean and variance of hydrological response. Henceforth these hydrological-geomorphic analyze methods can be improved that hydrology response is directly analogized with DEM data.