• Parasites, Hosts and Diseases
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• v.60 no.3
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• pp.187-193
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• 2022

The positive rate of Clonorchis sinensis is the highest among intestinal parasites in the Republic of Korea (Korea). More than 1.2 million people were at risk of C. sinensis infection in Korea in 2012. An intensive control program is being implemented for residents of the 5 major river basins to reduce helminthic infections, including C. sinensis infection. This study evaluated the continuous intensive control program for parasitic diseases including clonorchiasis in areas near the 5 major river basins in Korea over the past 10 years (2011-2020). A total of 335,020 fecal samples (one sample per resident) prepared by the modified sedimentation technic were microscopically examined. Those who expelled helminth eggs were treated with anthelmintics through local health centers and re-examined 3 months later. The overall positive rate of helminths egg was 7.1%. The annual positive rates were dramatically decreased from 14.4% (2011) to 5.9% (2020). The egg positive rate was highest in C. sinensis (5.3%), followed by heterophyid flukes (1.5%) and Trichuris trichiura (0.2%). The prevalence of C. sinensis was significantly higher in males (7.6%) than in females (3.7%), and the highest in the 50-59 years (7.0%) age group. Our results are beneficial to establish prevention and control policies against helminthiases including clonorchiasis in endemic areas in this country.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.123-133
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• 2009

In this study, we developed the GIS-based Geomorpho-hydrological Watershed Modeling System($G^{2}WMS$) which could consider both nonlilear rainfall-runoff relationship based on Geomorpho-Climatic Unit Hydrograph(GCUH) as well as watershed system inducing river routing. The developed new model was calibrated at the gaged rainfall events at natural watersheds and previewed to apply at the ungaged mountain basins, such as Sulma basin for small mountain basin and Andong-Dam basin for large scale basin, compared single with partitioned basin in the observed unit hydrographs and rainfall-discharge events. Finally, at the large scale Andong dam basin, we concluded that partitioned basin cases which including th nonlinear GCUH and river routing methods were superior to single basins which including the traditional methods in rainfall-discharge simulation at the mountain basins.

• Spatial Information Research
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• v.10 no.2
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• pp.275-287
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• 2002

Rainfall-Runoff Analysis in Whangryong River Basin was made using HEC-HMS and HEC-GeoHMS. The Basin was divided into three sub-basins using HEC-CeoHMS and GIS. Then, GIS input data were derived from each sub-basins. SCS CN runoff-volume model, Snyder's UH direct-runoff model, exponential recession baseflow model and Muskingum routing model in HEC-HMS were used to simulate the runoff volume using selected rainfall event and the parameters were optimized. Peak flowrate calculated using optimized parameters was compared to the observed flowrate in the basin. The result proved to be good agreement with each other. Optimized parameters in this local basin can be used to calculate the peak flowrate in the future.

• KCID journal
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• v.18 no.1
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• pp.58-67
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• 2011

The HSPF (Hydrological Simulation Program-Fortran) model was applied to Mangyeong river watershed to examine its applicability through calibration using monitoring data. For the model application, digital maps were constructed for watershed boundary, land-use, Digital Elevation Model of Mangyeong river watershed using BASINS (Better Assessment Science for Intergrating point and Nonpoint Sources) program. The observed runoff was 1976.4mm while the simulated runoff was 1913.4mm from 2007 to 2008. The model results showed that the simulated runoff was in a good agreement with the observed data and indicated reasonable applicability of the model. In terms of water quality, trends of the observed value were in a good agreement with simulated value despite its model performance lower than expected. However, its reliability and performance were with the expectation considering complexity of the watershed, pollutant sources and land use intermixed in the watershed. Overall, we identified application of HSPF model as reliable evidence by model performance.

• Membrane and Water Treatment
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• v.8 no.5
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• pp.423-435
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• 2017

Settling Basins are one of the most important and popular methods for removal of suspended sediments irrigation and drainage networks or power canals taking off from an alluvial river and wastewater treatment plant. Improving the performance and so increasing sediment removal efficiency of settling basins by an alternative method is necessary. In the present work, the effect of baffle and its angle of attack with the flow (${\theta}$) on the sediment removal efficiency is investigated by conducting a series of experiments on a straight canal with 8 m length, 0.3 m width and 0.5 m height and 3 m length of basin equipped with an adjustable glass baffle. A numerical analysis has been carried out using ANSYS Fluent 3D software (a general purpose computational fluid dynamics simulation tool) for three Froude numbers from the experiments. The numerical and experimental results were found to match reasonably well.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.431-444
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• 2017

This study was carried out to review the guidelines being used by law and national policy concerned on river environments management and suggest the applicability of newly developed river environment assessment system. In the current legal system, the national river environment management system is insufficient in securing an independent status in the legal institutional system which is separated to the Ministry of Land, Transport and Infrastructure and the Ministry of Environment. And the river environment assessment system of the national standard, which is a core matter, has not been established yet. In particular, there is a lack of integrated approach between the upper and lower plan or related plans on water resources, water quality, river environment and aquatic ecosystem management. In addition, the consistency and effectiveness as the process of planning and design according to the current status and comprehensive analysis and evaluation of the river environment were not secured either. To integrate national river environment management system and improve efficiency, I proposed the establishment of hierarchy and connection between national river plans, and the adoption and application of developed assessment system based on characteristics of river environment in Korea. Finally, I proposed the separated application with dividing the developed assessment system including the naturalness of river environment and suitability of water friendly activity into both assessment method for management plan of water resources of river basins & basic river plan respectively.

• Journal of Environmental Science International
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• v.9 no.6
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• pp.455-462
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• 2000

This study aims at the development of the model for a forecasting of water quality in river basins using artificial neural network technique. Water quality by Artificial Neural Network Model forecasted and compared with observed values at the Sangju q and Dalsung stations in Nakdong river basin. For it, a multi-layer neural network was constructed to forecast river water quality. The neural network learns continuous-valued input and output data. Input data was selected as BOD, CO discharge and precipitation. As a result, it showed that method III of three methods was suitable more han other methods by statistical test(ME, MSE, Bias and VER). Therefore, it showed that Artificial Neural Network Model was suitable for forecasting river water quality.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.218-218
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• 2015

Urbanization and waterworks construction in natural watershed have been causing higher flood risks in lowland areas. Detention basins have become one of the most efficient fundamental instruments for storm water and environmental management at watershed scale. Nowadays, there are many studies coupled numerical methods of flood routing with optimization algorithms to investigate factors that impact on the efficiency of detention basins in flood reduction in a watershed, such as detention basin location, size, and cost and watershed characteristics. Although these couplings have been become more widespread but cumbersome computation and hydraulic data requirement still are their limitations. To tackle the procedure efforts due to numerical integration and data collection, simple approach is proposed to primarily estimate effects of detention basins. The approach basis is the linear system theory applied to the solution of hydrologic flood routing. The paper introduces an analytical method for estimating detention effects deriving by recent studies and innovatively analyses this equation on fractal perspective. Then, an optimization technique is performed by applying harmony search algorithms (HSA) to optimize efficiency of detention basins at watershed scale. The location and size of upstream detention basin are simultaneously obtained. Finally, the proposed methodology, practically applied for a real watershed in Kan river, Iran.

• Journal of Korea Water Resources Association
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• v.45 no.10
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• pp.969-981
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• 2012

In this study, we analysed hydrologic variability in quantity and onset of annual maximum flow and low flow by impacts of the different phases of ENSO (El Ni$\tilde{n}$o Southern Oscillation) over the Han River Basin. The results show that annual maximum flow has increased statistically significant about 48.3% of all over the watershed. The onset of annual maximum flow was delayed in the west of the Han River basins and in the east of the basins was likely to be rapid onset. Also, this study shows that 7-day low flow was deceased statistically significant about 26.0% of the total area in the Han River Basin, and onset of 7-day low flow tends to be faster in the upper-middle basins of the Han River. The onset of annual maximum flow shows similar pattern during the CT (Cold tongue)/WP (Warm-pool) El Ni$\tilde{n}$o years, but annual maximum flow appeared less in 89.0% of all basins during the CT El Ni$\tilde{n}$o years. In addition, the onset of 7-day low flow tended to be faster about 17 days on average during the WP El Ni$\tilde{n}$o years, and 72.7% of the basins show significant increase during the CT El Ni$\tilde{n}$o years. Consequently, it was found that the different phases of CT/WP El Ni$\tilde{n}$o have effects on sensitivity to variability in quantity and onset of water resources over the Han River Basin. We expect that the present diagnostic study on hydrological variability during different phases of ENSO will provide useful information for long-term prediction and water resources management.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.133-146
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• 1999

Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.