• Journal of Korea Water Resources Association
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• v.53 no.1
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• pp.71-82
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• 2020

The objective of this study is to evaluate the instream flow in the North Han River basin according to the operation of Imnam Dam in North Korea. The water budget and instream flow satisfaction were analyzed using hourly, daily and monthly data of Water Management Information System (WAMIS) from Jan. 1991 to Dec. 2018. As a analysis result of water budget using hourly data in the North Han River basin, although inflows compared with dam release in the upstream basin of Peace Dam-Hwacheon Dam and Chuncheon Dam-Soyanggang Dam-Uiam Dam were calculated as negative values, the reasonable results using daily and monthly average data were estimated. It showed that the results of water budget analysis of dam inflow and total release may be different by time units of data. The monthly average inflow of Hwacheon Dam decreased significantly after the construction in 2003 of Imnam Dam, which confirmed that the operation of Imnam Dam had a significant effect on the dams in the North Han River basin. The operation of Imnam Dam is one of the main reasons for the lack of instream flow and total shortage amounts and shortage period increased up to +330% due to the decrease in inflow and total release of dams in the North Han River water after the operation of Imnam Dam. It is necessary to study various plans to secure instream flow including transboundary river management

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.287-287
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• 2023

Surface water-groundwater interaction (SWGI) is an important hydrological process that influences both the quantity and quality of water resources. However, regional scale SWGI model calibration and uncertainty analysis have been a challenge because integrated models inherently carry a vast number of parameters, modeling assumptions, and inputs, potentially leaving little time and budget to explore questions related to model performance and forecasting. In this study, we have proposed the application of iterative ensemble smoother (IES) for uncertainty analysis and calibration of the widely used integrated surface-subsurface model, SWAT-MODFLOW. SWAT-MODFLOW integrates Soil and Water Assessment Tool (SWAT) and a three-dimensional finite difference model (MODFLOW). The model was calibrated using a parameter estimation tool (PEST). The major advantage of the employed IES is that the number of model runs required for the calibration of an ensemble is independent of the number of adjustable parameters. The pilot point approach was followed to calibrate the aquifer parameters, namely hydraulic conductivity, specific storage, and specific yield. The parameter estimation process for the SWAT model focused primarily on surface-related parameters. The uncertainties both in the streamflow and groundwater level were assessed. The work presented provides valuable insights for future endeavors in coupled surface-subsurface modeling, data collection, model development, and informed decision-making.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.822-833
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• 2010

Temperature increase due to climate changes causes change of water temperature in rivers which results in change of water quality etc. and the change of river ecosystem has a great impact on human life. Analyzing the impact of current climate changes on air and water temperature is an important thing in adapting to the climate changes. This study examined the effect of climate changes through analyzing air temperature trend for Nakdong river basin and analyzed the elasticity of air-water temperature to understand the effect of climate changes on water temperature. For analysis air temperature trend, collecting air temperature data from the National Weather Service on main points in Nakdong river basin, and resampling them at the units of year, season and month, used as data for air temperature trend analysis. Analyzing for elasticity of air-water temperature, the data were collected by the Water Environment Information system for water temperature, while air temperature data were collected at the National Weather Service point nearest in the water temperature point. And using the results of trend analysis and elasticity analysis, the effect of climate changes on water temperature was examined estimating future water temperature in 20 years and 50 years after. It is judged that analysis on mutual impact between factors such as heat budget, precipitation and evapotranspiration on river water temperature affected by climate changes and river water temperature is necessary.

• Wind and Structures
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• v.21 no.6
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• pp.597-607
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• 2015

With an increasing demand of a renewable energy, new offshore wind turbine farms are being planned in some parts of the world. Foundation installation asks a significant cost of the total budget of offshore wind turbine (OWT) projects. Hence, a cost reduction from foundation parts is a key element when a cost-efficient designing of OWT budget. Mono-piles have been largely used, accounting about 78% of existing OWT foundations, because they are considered as a most economical alternative with a relatively shallow-water, less than 30 m of seawater depth. OWT design standards such as IEC, GL, DNV, API, and Eurocode are being developed in a form of reliability based limit state design method. In this paper, reliability analysis using the response surface method (RSM) and numerical simulation technique for an OWT mono-pile foundation were performed to investigate the sensitivities of mono-pile design parameters, and to find practical implications of RSM reliability analysis.

• The Journal of Sustainable Design and Educational Environment Research
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• v.13 no.2
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• pp.13-25
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• 2014

The recent trend has been consistently raised by the media of educational environment issues such as deteriorated existing school facilities, water-leaks due to the lack of proper maintenance and poor toilet facilities. For the efficient use of the budget to be used for maintenance of school facilities, an effort to extend the life of the facility to the max is needed. However, current maintenance system of school facilities is to deal with the defects after discovered, and consequently the durable period is shortened due to early deterioration of facilities and efficient budget execution cannot be realized. For this reason, the result emphasizes the need to improve maintenance management system of school facilities, and proposes a systematic bill of school facilities maintenance according to expert investigation and correlation analysis through school facilities maintenance-related information that is distributed to a number of laws.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.363-372
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• 2000

In order to overtake a quantitative analysis of effect of anthropogenic heat and different land-use on urban thermal environment numerical simulation of surface energy budget was carried out under typical summer synoptic condition. It is beneficial to understand surface temperature of complex urban surace. The different land-use types are classified of rice field farm fruit garden residential region forest water and swamp by using map scaled 1/25000 of Pusan metropolitan. The model predicts that maximum heat island intensity in the central part of Pusan is 7$^{\circ}C$ at 2000 LST in summertime. The surface temperature is propotional to the density of constructions. The effect of anthropogenic heat generation on surface temperature is the increase of 0.3$^{\circ}C$ at 1400LST in the central part of Pusan during summertime.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.527-537
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• 1997

Reliability, resiliency and vulnerability for the risk analysis are mathematically defined as the evaluation standard of risk level to characterize the risk which influences water resources management and optimal reservoir operations. Monthly inflows are synthetically generated by stochastic generation model for a long-term reservoir water budget analysis, and this method is applied to the Dae-Cheong Multipurpose Dam. As a result of study, reliability based on occurrence, time and quantity are derived respectively. Also resiliency, vulnerability and resiliency inc\dices are estimated to evaluate the performance of water supply on reservoir system, and their relationships are evaluated.

• Journal of Korea Water Resources Association
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• v.33 no.S1
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• pp.48-56
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• 2000

In this paper, properties of hydrologic cycle in three experimental catchments were compared and different types of a lumped parametric model were applied to understand the hydrologic cycle in the catchments. One of them is a forest catchment and another one includes the reclained upland fields and last one does terraces paddy fields. The comparison of hydrologic properties showed that the differences in land used have great influences on the soil properties of surface layer, which cause changes in hydrologic processes such as evapotranspiration and storm runoff et.al. By the runoff analysis models, good agreements between observed and calculated discharge from the catchments were obtained and it was found that the differences in values of optimized model parameters and water budget components reflect those in the hydrologic cycle among them.

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.48-56
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• 2000

In this paper, properties of hydrologic cycle in three experimental catchments were compared and different types of a lumped parametric model were applied to understand the hydrologic cycle in the catchments. One of them is a forest catchment and another one includes the reclaimed upland fields and last one does terraces paddy fields. The comparison of hydrologic properties showed that the differences in land use have great influences on the soil properties of surface layer, which changes in hydrologic processes such as evapotranspiration and storm runoff et. al. By the runoff analysis models, good agreements between observed and calculated discharge from the catchments were obtained and it was found that the differences in values of optimized model parameters and water budget components reflect those in the hydrologic cycle among them.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.24-32
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• 2005

Budget distribution system suporting dam area was changed largely in 2005, and thus, population survey and area calculation for dam and needed to be performed based upon the new criteria. According to the former regulations, dam area was confined to inside of 5km from the H.W.L-line. However, new regulations divide it into two categories : inside and outside of catchment area within 2km from the H. W. L-line and those belong to 2~5km from the same line. In this study, topography, DEM, TIN and Hydrological Unit Map were build for the analysis of the Namgang Dam area. It shows that analysis of dam area using GIS methods produces a good results to be used for rational distribution of budget.