• Water Engineering Research
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• v.5 no.3
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• pp.133-146
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• 2004

Soil and water assessment tool (SWAT) was simulated based on the default parameters and a priori soil parameter estimation method in Bocheong watershed of Korea. The performance of the model was tested against the measured daily runoff data for 5 years between 1993 and 1997. The sensitivity analysis of SWAT model parameters was conducted to identify the most sensitive model parameters affecting the model output. The results of SWAT simulation indicate that the overall performance of SWAT in calculating daily runoff is reasonably acceptable. However, there is a problem in estimating the low flow components of streamflow since the low flow components simulated by SWAT are significantly different from the measured low flow. The sensitivity analysis with SWAT points out that soil related parameters are the most sensitive parameters affecting surface and ground water balance components and groundwater flow related parameters exhibit negligible sensitivity.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.194-208
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• 2021

The Hwanggang Dam in North Korea is located upstream of the Imjin River which is a shared river in the border area. It is known to have a reservoir capacity of 350 million cubic meters and releases a discharge primarily for generating hydroelectric power and partly for transferring to the Yesung River basin. Due to the supply of water from the Hwanggang Dam to another basin, the flow of the Imjin River has decreased, which has a negative impact on the water supply, river maintenance flow, water quality, and ecological environment in Korea. However, due to the special national security issue of the South and North Korea border region, the hydrological data is not shared, and the operation method of the Hwanggang Dam is unknown, so there is a risk of damage to the southern part of the downstream area. In this study, the monthly diversion as the long-term runoff concept was derived through the calibrated hydrological model based on optical remotely sensed Images and water balance analysis. As a result of the water balance analysis from January 2019 to September 2021, the average diversion of the Hwanggang Dam was 29.2m³/s, which is equivalent to 922 million tons per year and 45.6% of the annual inflow of 2.02 million tons into the Hwanggang Dam.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.431-434
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• 2003

This research developed a method for the estimation of groundwater recharge by yielding daily soil moisture content and watershed evapotranspiration from the water balance concept of the unsaturated and saturated layers in rainfall-runoff model called DAWAST. The goal of the research is to estimate the groundwater recharge fulfilling conditions of the safe discharge for any season. To meet this goal, the data of groundwater level and stream flow rate have been monitored in a study area and used to validate the model.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.2
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• pp.59-68
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• 2001

A water balance analysis was performed for a paddy field neighboring the Dongchang stream, downstream of the Unmun reservoir, which is constructed for the urban water supply. Daily rainfall data were collected and irrigation water flow rate, drainage flow rate, evaportranspiration, infiltration, and piezometeric head were measured in the field. The flow rates were continuously observed by water level logger during the growing season. The evaportranspiration and the infiltration were measured by N-type depletion meter and cylindrical infiltrometer, respectively. PVC pipes with 12mm diameter were used for piezometric head measurement. Total Irrigation and drainage flows were 3,608mm and 1,170mm in 1999, and 3,971mm and 1,548mm in 2000, respectively. The mean and range of the daily infiltration rate were 4.4mm/d and 3.4mm/d to 5.5mm/d in 1999 and 5.1mm/d and 4.1mm/d to 6.5mm/d in 2000, respectively. The net ground water flow including the change of soil water storage was 2,855mm in 1999 and 2,540mm in 2000. The evapotranspiration was 458.3mm in 1999 and 553.5mm in 2000. The range of daily evapotranspiration rate was from 1.6 to 8.7mm/d. The return flow ratio was about 32% in 1999 and 39% in 2000 and three year average was 35% including previous study in 1997. The amount of irrigation water was much higher than design standards or references in this study, This was caused by the inadequate water management practice in the area where water was oversupplied on farmers’ request rather than following sound water management principles.

• Journal of Korea Water Resources Association
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• v.55 no.5
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• pp.321-331
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• 2022

In this study, we tried to present a method for calculating the amount of regression using a watershed modeling method that can simulate the hydrological mechanism of water balance analysis and agricultural water based on watershed unit. Using the soil water assessment tool (SWAT), a watershed water balance analysis was conducted considering the simulation of paddy fields for the Manbongcheon Standard Basin (97.34 km²), which is a representative agricultural area of the Yeongsan river basin. Before evaluating return flow, the SWAT was calibrated and validated using the daily streamflow observation data at Naju streamflow gauge station (NJ). The coefficient of determination (R²), Nash-Sutcliffe Efficiency (NSE), Root-Mean-Square Error (RMSE) of NJ were 0.73, 0.70, 0.64 mm/day. Based on the calibration results for three years (2015-2017), the quick return flow and the return rate compared to the water supply amount for the irrigation period (April 1 to September 30) were calculated, and the average return flow rate was 53.4%. The proposed method of this study may be used as foundation data to optimal agricultural water supply plan for rational watershed management.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1900-1908
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• 2014

This paper establishes a compact and practical model for a water-wall system comprising supercritical once-through boilers, which can be used for automatic control or simple analysis of the entire boiler-turbine system. Input and output variables of the water-wall system are defined, and balance equations are applied using a lumped parameter method. For practical purposes, the dynamic equations are developed with respect to pressure and temperature instead of density and internal energy. A comparison with results obtained using APESS, a practical thermal power plant simulator developed by Doosan Heavy Industries and Construction, is presented with respect to steady state and transient responses.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.15-25
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• 2004

For the effective operation of irrigation reservoirs, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. In this study, the flood effective analysis system was developed through the integration of long-term water budget analysis model, GIS-based HEC-HMS model and HEC-RAS model. The system structure consists of long-term water budget model using modified TANK theory, flood runoff and flood effects analysis model using HEC-GeoHMS, HEC-HMS and HEC-RAS models. The flood effects analysis system simulated the flood runoff from the upstream, downstream flood and long-term runoff of the watershed using the observed data collected from 1998 to 2002 of Seongju dam. The simulated results were reasonably good compared with the observed data. The optimal management method of the reservoir during the whole season is suggested in this study, and the flood analysis system can be a useful tool to evaluate a reservoir operation quantitatively for the mitigation of flood damages of reservoir basin.

• The Journal of Advanced Prosthodontics
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• v.7 no.2
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• pp.93-97
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• 2015

PURPOSE. Xerostomia can diminish the quality of life, leads to changes in normal chemical composition of saliva and oral microbiata, and increases the risk for opportunistic infections, such as Candida albicans. Various artificial salivas have been considered for patients with xerostomia. However, the knowledge on the antifungal and antiadhesive activity of artificial saliva substitutes is limited. The aim of the present study was to evaluate influence of two artificial salivas on the adhesion of Candida albicans to the polymethylmethacrylate disc specimens. MATERIALS AND METHODS. Two commercial artificial salivas (Saliva Orthana and Biotene Oral Balance Gel) were selected. 45 polymethylmethacrylate disc specimens were prepared and randomly allocated into 3 groups; Saliva Orthana, Biotene-Oral Balance gel and distilled water. Specimens were stored in the artificial saliva or in the sterile distilled water for 60 minutes at $37^{\circ}C$. Then they were exposed to yeast suspensions including Candida albicans. Yeast cells were counted using ${\times}40$ magnification under a light microscope and data were analysed. RESULTS. Analysis of data indicated statistically significant difference in adhesion of Candida albicans among all experimental groups (P=.000). Findings indicated that Saliva Orthana had higher adhesion scores than the Biotene Oral Balance gel and distilled water (P<.05). CONCLUSION. In comparison of Saliva Orthana, the use of Biotene Oral Balance Gel including lysozyme, lactoferrin and peroxidase may be an appropriate treatment method to prevent of adhesion of Candida albicans and related infections in patients with xerostomia.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.215-219
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• 2004

In this study, Types of irrigation water development in islands district were classified. The types were reservior, fleshwater lake, pumped storage, etc. Most of islands district has delveloped reuse irrigation system as a pumped storage system. But. Irrigation water-reuse ratio doesn't define a basis clearly and the value of measurement for water-reuse ratio doesn't exist so far. so, we measured Irrigation water-reuse to clarify for water-reuse ratio in a pumped storage system. Also, we need to develop hydrologic analysis and water balance method with characteristic factor of islands district. that make use of plan about security of agriculture water efficiently in islands district.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.1-7
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• 2013

The dam plan quantity of constructive and water supply quantity of present time are showing a difference with change in climate and augmentation of water demand for multipurpose dams in Nakdong river basin. But revaluates a water supply ability the method or the process is official for is not taking a position, so actual condition applies the plan quantity of dam constructive. Considers various situation of actual multipurpose dam from research sees consequently and in K-WEAP is an integrated water resources evaluation plan model applies as water permit availability multipurpose dam, currently water permit availability comparison, analyzed. In this study, the natural daily flow data and apply the dimensions of the reservoir, and for more than 30 years of the long-term water balance analysis conducted by Date Nakdong river basin can supply reservoirs are large quantity of permits available is presented.