• 한국물환경학회지
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• 제25권1호
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• pp.125-135
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• 2009

Reliable long-term flows by SWAT-K model were applied to the relationship between stream flow and pollutant load derived from 8-day measured data of Ministry of Environment (MOE) in order to obtain continuous loadograph and evaluate accuracy in water quality modeling for the Chungju dam watershed. The measured flow were compared with flow duration curve from the model, and it showed that measured values corresponded to the almost full range of stream flow conditions except at Odae A. And there was significant relationship ($R^2=0.60{\sim}0.97$) between measured flow and water quality load at all unit-watersheds. Applying this relationship to simulated flows, continuous loadograph was obtained and compared with modeled pollutant loads. Although there were some differences during some dry and flood seasons, those were not significant and overall trend showed a good agreement. From the results, we would be able to derive a continuous loadograph based on measured data at total maximum daily loads (TMDLs) unit-watersheds on a national scale, in which stream flow and water quality have been measured at 8-day intervals since 2004, and this could be helpful to utilize distributed water quality models with difficulty in calibrating and validating parameters from lack of measured data at present.

• 설비공학논문집
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• 제8권1호
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• pp.45-54
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• 1996

An experimental investigation on the two-phase flow through tube orifices was performed with the refrigerant mixture of R32/125/134a(30/10/60). A series of tests were conducted to generate wide range of data at varying operation conditions with four short tubes. The tests include both single and two-phase flow conditions at the inlet of the short tube with different oil concentrations. Experimental data were presented as a function of major operating parameters and short tube diameter. Based on test results and data analysis, a semi-empirical flow model was developed to predict the mass flow rate through short tube orifices with a given set of conditions. The flow model was formed to cover both single and two-phase flow at the inlet of short tube with considering the effects of oil concentration.

• Journal of Mechanical Science and Technology
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• 제19권12호
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• pp.2289-2295
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• 2005

Two-Phase flow pattern and pressure drop data were obtained for pure refrigerants R134a and R123 and their mixtures as test fluids in a horizontal tube. The flow pattern is observed through tubular sight glasses located at inlet and outlet of the test section. The flow map of Baker developed for air-water two-phase flow at atmospheric pressure failed to predict the observed flow patterns at the higher value of the mass velocity used in the present study. The map of Kattan et al. predicted the data well over the entire region of mass velocity selected in the present study. The measured pressure drop increased with an increase in vapor quality and mass velocity. A new two-phase multiplier was developed from a dimensional analysis of the frictional pressure drop data measured in the present experiment. This new multiplier was found successfully to correlate the frictional pressure drop.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1121-1124
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• 1987

Previous methods to map from a FORTRAN-like specification into a systolic array were difficult to find data dependencies because the specification was expressed and executed sequentially. Data-flow graph(DFG)s show data dependencies explicitly. In this paper we show a mapping tool from a DFG specification into a systolic array. We introduce the concept of a Systolic Pattern Stream(SPS) and use that concept to derive a systolic array.

• 한국수자원학회논문집
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• 제45권1호
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• pp.91-99
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• 2012

본 연구에서는 수질오염총량관리단위유역의 말단부에서 8일 간격으로 계측된 유량자료가 있을 때 이를 연속적인 일유량으로 확대할 수 있는 방법론을 제시하였다. 이 방법은 부분계측이 이루어지는 지점의 결측치를 인근 혹은 수문학적으로 유사한 지점에서 연속계측된 유량자료를 이용하여 보완하는 방식이다. 이를 위해 먼저 부분계측이 수행된 날짜와 같은 날의 유량을 연속계측자료로부터 추출한다. 그 다음 두 자료간에 상관도가 높다면 이를 잘 표현하는 확장식을 개발하고 이 식을 통해 결측치를 내삽 또는 외삽한다. 본 연구에서는 두 자료간 상관성을 잘 묘사하는 방법으로 분산유지법을 제안하였고, 이를 부분계측과 연속계측이 동시에 수행된 지점의 유량자료를 통해 그 정확성을 검증하였다. 검증된 분산유지법을 이용하여 한강수계 총량관리단위유역 중 15개 유역을 선택하여 각 유역의 말단부에 8일 간격으로 계측된 유량을 연속 일유량으로 확장시켰다. 확장된 자료를 기반으로 유황분석을 통해 저수량을 산정하였다.

• 한국물환경학회지
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• 제35권6호
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• pp.481-496
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• 2019

The Ministry of Environment has measured streamflow at eight-day intervals for the estimation of standard flow of the Total Maximum Daily Loads (TMDL) system. This study identified the availability of the partially measured the eight-day interval data for estimating standard flow and found the optimal extension techniques of standard flow. The study area was selected for the Nakbon-A watershed in the Nakdong River, and four streamflow record extension techniques of standard flow were considered: extension, percentile, drainagearea, and regional regression methods. The flow duration curve (FDC) using the eight-day interval streamflow data indicated very high Nash and Sutcliffe Efficiency (NSE) values above 90 % from FDC-II to FDC-VII compared to FDC-VIII, the standard FDC. This result demonstrates that FDC using daily data of three-six cumulative years could represent standard FDC fairly well. For the streamflow record extension techniques of standard flow, the percentile method was selected as the optimal alternative, showing the minimal difference from FDC-VIII. These results validate the availability of the eight-day interval streamflow data in the standard flow estimation and the application of extension techniques. It seems that these results could reduce the uncertainty of partially measured streamflow data for water quantity and quality management.

• 지구물리와물리탐사
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• 제20권4호
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• pp.199-206
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• 2017

해상탐사에서 얻어지는 현장자료는 바람, 파도, 조류, 배경매질의 유속 등 다양한 환경요소에 영향을 받는다. 배경매질의 유속을 제외한 대부분의 환경요소는 자료처리 단계에서 적절한 보정이 이루어지고 있다. 본 연구에서는 배경매질의 유속정보가 파형역산에 미치는 영향을 분석하기 위해 배경매질의 유속정보를 고려하는 파동 방정식 모델링을 활용하여 관측자료를 생성하고, 생성된 자료를 통해 수치 실험을 진행하였다. 수치예제에는 다소 비현실적인 유속이 적용된 결과도 포함되어 있다. 이와 더불어, 탐사자료의 유속정보를 수치적 기법으로 도출하여 역산을 수행하는 알고리즘을 제안하였다. 제안된 알고리즘은 수정된 Marmousi2 모델에 적용하여 유속에 따른 결과를 얻고자 하였다. 기존의 유속을 고려하지 않은 역산 결과와 제안된 알고리즘으로 수행한 역산 결과 비교를 통해 유속의 세기가 갱신되는 물성정보에 미치는 영향을 확인하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.63-66
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• 2003

This study applied a hydrogeological field survey and isotope investigation to identify source locations and delineate pathways of groundwater contamination by nitrogen compounds. The infiltration and recharge processes were analyzed with groundwater-level fluctuation data and oxygen-hydrogen stable isotope data. The groundwater flow pattern was investigated through groundwater flow modeling and spatial and temporal variation of oxygen isotope data. Based on the flow analysis and nitrogen isotope data, source types of nitrate contamination in groundwater are identified. Groundwater recharge largely occurs in spring and summer due to precipitation or irrigation water in rice fields. Based on oxygen isotope data and cross-correlation between precipitation and groundwater level changes, groundwater recharge was found to be mainly caused by irrigation in spring and by precipitation at other times. The groundwater flow velocity calculated by a time series of spatial correlations, 231 m/yr, is in good accordance with the linear velocity estimated from hydrogeologic data. Nitrate contamination sources are natural and fertilized soils as non-point sources, and septic and animal wastes as point sources. Seasonal loading and spatial distribution of nitrate sources are estimated by using oxygen and nitrogen isotopic data.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.197-212
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• 1997

The performance of a torque converter can be expressed by the performance parameters such as flow radius and flow angle, on the mean flow path. The geometric analysis of the torque converter is required to determine these parameters for the modeling of the torque converter. In general, the blade shape is depicted by three dimensional data at the mid-surface of blade or those of the pressure and suction side. To generate three dimensional model of the blade using the data mentioned above, a consistent data format and a shape generation algorithm are required. This paper presents a useful consistent data format of the blades and an algorithm for the geometrical shape generation. By the geometric analysis program to which the shape generation algorithm is embedded, the variation of blade angles in rotating element analyzed. Then finally, the analyzed results of geometric profile of a blade are compared with those of the blade design principle, so called forced vortex theorem.

• 한국정보통신학회논문지
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• 제4권3호
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• pp.681-687
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• 2000

최적화란 비효율적인 코드를 구분해 내서 실행 속도 및 기억 공간의 효율성을 높여 주는 방법으로 컴파일러의 각 단계에서 수행된다. Augustus K. Uh떼 의해 제안된 Ideograph는 입력 프로그램에 대한 제어 의존성과 자료 의존성에 관한 정보를 동시에 표현할 수 있어 코드 최적화 단계에서 효과적으로 이용될 수 있으며 프로그램에 존재하는 병렬성을 표현하는데 효과적이다. 구문 트리는 원시 프로그램 정보를 효율적으로 표현할 수 있는 중간 표현으로서 컴파일러 구천에 널리 사용되고 있다. 본 논문에서는 원시 프로그램의 중간 표현인 구문 트리를 입력으로 받아 최적화 정보를 추출한 후 제어 흐름 및 자료 흐름 분석 정보를 추출하여 제어 의존성과 자료 의존성을 Ideouaph에 동시에 표현한다.