• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.81-87
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• 2010

On the SSang-chi gauging station, the discharge had been measured by the rod float method for the past twelve years. However the shifts of the rating curves are too big to be accepted. The major factors of rating curve variation were reviewed for shift analysis. To estimate the discharge measured by rod float method, two cross sections and their stages are generally required. But, the rating curves had been derived only with the observed depth of gauging station since the cross sections were not available. To correct the errors, the reference rating curve was developed. In this study, the water surface slopes of the curve were simulated by RMA2 model. The historical rating curves were re-developed by the calculated discharges on the base of the water surfaces. The results show that the range of fluctuation decreased and rating curves in recent years are physically reasonable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5578-5586
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• 2012

The accurate estimation of discharge is very essential as the important factor of river design for the utilization and flood control, hydraulic construction design. The present discharge production is using the stage-discharge relationship curve in the river. The rating curve uses the method by predicting the discharge based on regression analysis using the measured stage and discharge data in a flood season. The method is comparatively convenient and has especially advantages in that it can predict the discharge having the difficulty of observation in a flood season. However, this method has basically room for improvement because the method only uses the relationship between stage and discharge, and doesn't reflect the hydraulic parameters such as hydraulic radius, energy slope, roughness, topography, etc.. Therefore, in this study, discharge was predicted using the convenient calculation method with empirical parameters of the Manning and Chezy equations, which were proposed by Choo et at (2011) in KSCE as a new methodology for estimating discharge in open channel. The proposed method can conveniently estimate empirical parameters in both of Manning and Chezy equations and the discharge is estimated in the open channels. There are proved by using data measured in meandering lab. channel and India canal and the accuracies show about determination coefficient 0.8. Accordingly, this method will be used in actual field if this study is continuously conducted.

• Analytical Science and Technology
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• v.8 no.4
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• pp.443-448
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• 1995

Three anode configurations of six-jet, cone-jet and cylindrical-jet are tested for their analytical performance under power mode operation. The effect of pressure, power and gas flow rate on atomic absorption signals have been studied. The increase of atomic absorption signal of sample element is observed at a fixed pressure in all configurations as the gas flow rate increase up to 300-600 seem, and as the power dissipated in the glow discharge cell increase. The lower the pressure is in the glow discharge cell at a fixed discharge power and argon flow rate, the greater the absorbance of sample element is. The optimum conditions are taken from these data and a calibration curve of Cu in low-alloy steel sample is obtained. In this calibration curve, six-jet configuration shows the best analytical results varies as the sample element.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.732-735
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• 2009

In this paper, high Xe(Ne+Xe 10%, 20%, 30%) AC-PDP's discharge characteristics according to aging time were studied. The static margin, Vt close curve, discharge time lag was measured for experiments. According to increase of Xe partial pressure, the static margin and luminance was increased. As the result of analysis for misfiring probability, the misfiring is frequently occurred in accordance with increasing of aging time. To improve misfiring, we proposed 3Reset waveform and achieved misfiring probability which was improved.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.114-124
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• 2019

The objective of this study is to reduce the uncertainty of the river discharge estimation method using the stage-discharge relation curve. It is necessary to consider the quantitative and accurate estimation method because the river discharge data is essential data for hydrological interpretation and water resource management. For this purpose, the parameters estimated by Bayesian and Bootstrap methods are compared with the ones obtained by stage-discharge relation curve. In addition, the Bayesian and Bootstrap methods are applied to assess uncertainty and then those are compared with the confidence intervals of the results from standard error method which has t-distribution. From the results of this study, The estimated value of the regression analysis developed through this study is less than 1 ~ 5%. Also It is confirmed that there are some areas where the applicability is better than the existing one according to the water level at each point. Therefore, if we use more suitable method according to the river characteristics, we could obtain more reliable discharge with less uncertainty.

• Journal of computational fluids engineering
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• v.8 no.3
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• pp.32-40
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• 2003

CFD analyses of the three-dimensional turbulent flow in the impeller and diffuser of an axial flow pump including suction and discharge parts are presented and compared with experimental data. The purpose of the current study is to validate the CFD method for the performance analysis of the main coolant pump for SMART and to investigate the effect of suction and discharge shapes on the pump performance. To generate a performance curve, not only the design point but also the off-design points were computed. The results were compared with available experimental data in terms of head generated. At the design point, the analysis accurately predicts the experimental head value. In the range of the higher flow rates, the results are also in very good agreement with the experimental data, in magnitude but also in terms of slope of variation. For lower flow rates, the results shows that the analysis considering the suction and discharge well describe the typical S-shape performance curve of the axial pump.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.2
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• pp.66-72
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• 2000

The purpose of this study is establish a recession curve for low flow discharge in the Ssangchi basin. For this study, we selected 34 recession segments and calculated recession constants and initial discharges. The average initial discharge is 0.40 ㎥/sec and the recession constant is 0.86. With using the initial discharge and the recession constant, We got the non-linear recession cure equation. This non-linear equation is more reasonable fit than the linear equation of the recession curve for low flow.

• Water for future
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• v.28 no.6
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• pp.169-181
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• 1995

No correction has been made for the rating curve of Goan Station since 1986 even though there has been a severe bed degradation until now. Furthermore, it was informed to Han River Flood Control Center that there was a difference between the discharge released from Paldang dam and the discharge observed at Goan station during 1990 flood. By considering such river bed changes, hydraulic model experiment with 1/100 scale was performed for the range of 2.2 km, which covers from Paldang dam to the downstream of Goan station. From this experiment, the rating curve was obtained by considering the discharges from Paldang dam and the corresponding water levels at Goan station. Also, the exsitingand the proposed rating curves were compared with those by computational method of RMA-2V.

• Journal of Korea Water Resources Association
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• v.36 no.1
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• pp.33-44
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• 2003

Flow duration curves provide a compact summary of streamflow variability. In this study, characteristics of the dimensionless flow duration curve in natural rivers with the unregulated discharge were investigated. An analysis of flow duration characteristics was conducted with discharge data at stage-gauging stations of IHP representative basins and of the major rivers in Korea. Discharge characteristics are dependent on area of watershed. However, flow duration coefficients except drought duration coefficient are independent on that. Abundant flow duration coefficient was constant value. The coefficient of flow duration variability defined in this study as the ratio of the normal stream flow over the drought one is decreased with increasing of the watershed area, which implies that the watershed area affects the drought flow duration variability more than the low flow one. And the coefficient of flow duration variability is increased with the river gradient.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.417-423
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• 1997

The objective of this study Is to supply basic data for large reservoir sedimentation research In future and make suggestions to maintain and opera능 the reservoir more of efficiently. At first, previous studios about the estimation of sediment yield rate were reviewed in Korea. And the discharge rating curves of upstream stage gauging stations and the correlation between dam Inflow and stage discharge were analyzed. With the analysis results, the spec유c sediment rate of Soyanggang dam was estimated as 608 m3/km2/yr. It was similar to that of Soyanggang dam feasibility study and 1994's field surveys of the reservoir than that of 1983's field surveys. Because the sediment rating curves were derived under the low discharge conditions, It needs to be checked under the flood conditions. However, the suggested methods such as flowrate analysis and sediment estimation will be useful to the sediment studios In future. Key words . reservoir sediment, sediment yield rate, rating curve, flowrate analysis.