• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.575-583
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• 2011

In this study, the plausible grid size was estimated to increase for efficiency of reservoir management using 3 dimensional water quality model. To validate utilization of a real time water quality management tool, ELCOM-CAEDYM model was applied to Soyang reservoir in korea. 100m grid size can represent the real topography and take out exact analysis results. $400{\times}400m$ grid can be easily used to analysis because of data capacity. Consequently, the grid size of 200m or 300m was recommended to establish 3D model considering the required simulation time and the irrelevance between horizontal grid size and vertical distribution for temperature and turbidity analysis.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.218-222
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• 2008

This study was carried out to establish standard analytical methods for Ginkgo biloba leaf extract. Ginkgo flavonoids, terpene lactones, ginkgolic acids were employed as reference compounds for analytical method. Analytical method of US Pharmacopoeia was adopted for flavonoids and terpene lactones, and a new method was developed for ginkgolic acids. Analytical methods established in this study could be applied to a reasonable and unified quality control of G. biloba leaf extract.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.241-245
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• 2008

Quantitative methods for the marker compounds of Cimicifugae Rhizoma, Achyranthis Radix, Artemisiae Capillaris Herba, Moutan Cortex Radicis and Arecae Semen, respectively, were developed using HPLC-DAD. Using the established methods, each extract of the natural medicines were evaluated. In addition, long term and accelerated stability test in the extracts were examined for six months. No significant change in content of the marker compounds of each extract observed during the time of investigation.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.72-72
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• 2016

최근 발생하고 있는 기후변화로 인하여 하천 및 저수지의 수질문제가 커지고 있다. 특히 여름철 부영양화로 인해 발생하는 녹조현상은 사회적인 문제로 과학적인 수질사고에 대한 예측과 관리가 필요한 실정이다. 수질예보는 정기적으로 하천 및 저수지의 수질을 예측하여 사용자에게 제공하는 분석기법으로 수질현황을 파악하고 수질을 관리하고 의사결정을 하는데 도움을 줄 수 있다. 수질예보에 사용되는 모형은 유역모형, 하천모형, 저수지모형이 있으며, 이중 하천 및 저수지에 주로 적용되고 있는 3차원 수리수질모형의 경우 격자의 개수가 많아 모의시간이 길어지게 되고 이로 인해 일일 수질 예보가 어렵게 된다. 3차원 수리수질모형의 모의속도를 개선하는 방법에는 하드웨어의 성능을 높이는 방법과 병렬화를 이용한 소프트웨어적인 방법이 있다. 이중 하드웨어의 성능을 높이는 방법은 컴퓨터의 사양을 높이는 방법으로 높은 비용이 소요된다. 하지만 병렬화 방법은 컴퓨팅 기술의 발전으로 멀티코어가 대중화가 된 최근에 코드의 적용만으로 모의속도를 향상시킬 수 있다. 본 연구에서 사용된 모형은 서호주대학에서 개발한 3차원 수리 수질모형인 ELCOM-CAEDYM 모형으로 적용된 병렬화 기법은 OpenMP(Open Multi-Processing)방법이다. 기존 직렬 컴퓨팅 방식으로 구성되어 한번에 한 개의 명령어 밖에 처리할 수 없었던 작업방법을 동시에 여러 개의 처리요소를 이용하여 명령을 실행할 수 있게 하는 방식이다. 하지만 CPU의 개수는 제한되어 있으며, Amdahl's law에 따르면 OpenMP방식의 병렬화시 속도개선효과는 95% 병렬화 프로그램에서 최대 CPU 개수의 제한이 없다면 20배 까지 속도향상이 가능하다고 하였다. 본 연구에서는 3차원 수리 수질예측 모형인 ELCOM-CAEDYM에 적용된 병렬화 기법을 적용하는데 있어 최적 CPU사용 개수를 파악 하고자 하였으며, 이를 통해 수질예보시스템을 운영하는데 가장 효율적인 방법을 찾아 적용하고자 하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.23-23
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• 2016

우리나라의 댐저수지는 홍수기에 상류로부터 다량의 부유물이 폐기물 등과 함께 일시에 유입되어 미관을 해치거나 상수원 수질을 악화시키는 등의 문제점을 가지고 있다. 이에 부유물의 하류확산을 방지하고 수거와 처리를 효율적으로 하기 위한 부유물 차단망이 설치되어 운영 중이다. 부유물 차단망의 설치위치는 저수지내의 흐름을 고려하여 부유물을 가장 효과적으로 차단할 수 있는 지점을 선정하여야 하나, 저수지 흐름을 고려하지 않고 설치될 경우 차단망이 빈번하게 훼손되거나 부유물이 적절하게 포집되지 못한 채 상류에 흩어지는 결과를 초래하기도 한다. 본 연구에서는 대형저수지인 소양댐과 신규 중소규모 댐인 영주댐의 부유물 차단망 최적 설치위치를 선정하기 위하여 3차원 모형을 이용하여 다양한 조건에서의 저수지내 흐름분포와 수리적 특성을 검토하였다. 적용모형은 3차원 수리동력학 모형인 ELCOM 모형을 적용하였으며, 홍수기 표면 유속장 분포, 수직수온분포 및 밀도류 발생지점 등을 종합적으로 분석하여 최적 설치지점을 검토하였다. 시뮬레이션 조건은 200년 빈도 홍수 유입에 대해 초기 수위에 따른 영향을 고려하기 위하여 갈수위, 풍수위 등으로 구분하여 분석하였다. 분석결과, 소양댐의 경우 기존 설치위치에서는 plunging point가 설치지점보다 하류에 위치하여 부유물 포집 기능에는 이상이 없으나 최대유속이 2 m/s를 초과하는 것으로 나타나 안정적 운영을 위하여 이전 설치하는 것이 적합할 것으로 판단되었다. 또한 신규댐인 영주댐에서는 다양한 시나리오에 대하여 분석한 결과 2개 지점이 적합한 것으로 분석되어 적치장 위치 등을 종합적으로 고려하여 최적위치를 선정하도록 하였다. 이와 같은 연구 결과는 부유물 차단망 설치설계기준 등에 반영되어 과학적인 댐 운영관리에 활용될 것으로 판단되며, 향후 보다 안정적인 시설물 관리에 기여할 수 있을 것으로 사료된다.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.3-12
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• 2018

The objective of this study was to evaluate the radius of influence of effluent of water treatment system developed for the purpose of improvement of reservoir water quality using fluorescent dye (Rhodamine-WT) tracer experiment and 3-D numerical model. The tracer experiment was carried out in a medium-sized agricultural reservoir with a storage capacity of $227,000m^3$ and an average depth of 1.6 m. A guideline with a total length of 160 m was installed at intervals of 10 m in the horizontal direction from the discharge part, and a Rhodamine measurement sensor (YSI 6130, measurement range $0-200{\mu}g/L$) was used to measure concentration changes in time, distance, and depth. Experimental design was established in advance through Jet theory and the diffusion process was simulated using ELCOM, a three dimensional hydraulic dynamics model. As a result of the study, the direct effect radius of the jet emitted from the applied water treatment system was about 50-70 m, and the radius of physical effect by the advection diffusion was judged to be 100-120 m. The numerical simulations of effluent advection-diffusion of the water treatment system using ELCOM showed very similar results to those of the impact radius analysis using the tracer experiment and jet flow empirical equations. The results provide valuable information on the spatial extent of the water quality improvement devices installed in the reservoir and the facility layout design.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.329-343
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• 2013

According to previous studies, the increased air temperature can lead to change of thermal stratification structure of lakes and reservoirs. The changed thermal stratification may result in alteration of materials and energy flow. The objective of this study was to predict the effect of climate change on the water temperature and stratification structure of Daecheong Reservoir, located in Geum River basin of Korea, using a three-dimensional(3D) hydrodynamic model(ELCOM). A long-term(100 years) weather data set provided by the National Institute of Meteorological Research(NIMR) was used for forcing the 3D model. The model was applied to two different hydrological conditions, dry year(2001) and normal year(2004). It means that the effect of air temperature increase was only considered. Simulation results showed that the surface water temperature of the reservoir tend to increase in the future, and the establishment of thermal stratification can occur earlier and prolonged longer. As a result of heat flux analysis, the evaporative heat loss can increase in the future than now and before. However, the convective heat loss and net long wave radiation from water surface decreased due to increased air temperature.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.199-202
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• 2008

A high performance liquid chromatographic (HPLC) method for the simultaneous determination of hesperidin and glycyrrhizin was established for the quality control of traditional herbal medicinal preparation, Pyungwi-san (PWS). Separation and quantification were successfully achieved with a Waters XTerra RP18 column ($5{\mu}m$, 4.6 mm I.D. ${\times}$ 150 mm) by gradient elution of a mixture of acetonitrile and water containing 0.03% phosphoric acid (pH 2.03) at a flow rate of 1.0 ml/min. The diode-array UV/vis detector (DAD) was used for the detection and the wavelength for quantification was set at 230 nm. The presence of hesperidin and glycyrrhizin in this extract was ascertained by retention time, spiking with each authentic standard and UV spectrum. All four compounds showed good linearity $(r^2>0.995)$ in a relatively wide concentration ranges. The R.S.D. for intra-day and inter-day precision was less than 7.0% and the limits of detection (LOD) were less than 60 ng. The mean recovery of each compound was 99.0-105.6% with R.S.D. values less than 4.0%. This method was successfully applied to the determination of contents of hesperidin and glycyrrhizin in three commercial products of PWS. These results suggest that the developed HPLC method is simple, effective and could be readily utilized as a quality control method for commercial PWS products.

• Journal of Environmental Impact Assessment
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• v.21 no.3
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• pp.367-380
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• 2012

There are many long and round shape shores due to terrain characteristics in Daecheong reservoir. Therefore it is indicated different spatial distribution of algae every year since the stream is being regulated by these terrain characteristics and reservoir operation about inflow and outflow discharge. Also oversupply of nutrient salt from tributaries of Daecheong reservoir where pollutants were concentrated generates massive growth of algae and depending on hydrological, reservoir operation condition, those proliferated algae at the stagnant tributaries moves to the mainstream of Daecheong reservoir which could create problems of water quality. In this study, it was analyzed the tendency of algae generation by examining algae occurring status for the last 4 years since 2008, and implemented hydraulic analysis at Daecheong reservoir through numerical tracer simulation by applying 3-dimensional hydrodynamic model, ELCOM. Also it was implemented a quantitative analysis of causal relationship based on the algae generation tendency and hydraulic behavior at Daecheong reservoir. Through numerical tracer simulation in this study, it could be noticed the degree of spread of inflow indicated similar trend to the algae occurring status at Daecheong reservoir and verified the different tendency of algae generation in 2011 unlike previous year caused by the rise of water temperature.

• Korean Journal of Pharmacognosy
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• v.41 no.4
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• pp.323-327
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• 2010

A high performance liquid chromatographic (HPLC) method for the simultaneous determination of dictamine, obacunone and fraxinellone was established for the quality control of traditional herb Dictamnus dasycarpus cortex. Separation and quantification were successfully achieved with a Shiseido C18 column ($5\;{\mu}m$, 4.6 mm I.D. ${\times}$ 250 mm) by gradient elution of a mixture of methanol and water at a flow rate of 1.0 ml/min. The diode-array UV/Vis detector (DAD) was used for the detection and the wavelength for quantification was set at 236 nm. The presence of dictamine, obacunone and fraxinellone in this extract was ascertained by retention time, spiking with each authentic standard and UV spectrum. All three compounds showed good linearity ($r^2$ > 0.999) in relatively wide concentration ranges. The R.S.D. recovery of each compound was 101.0~103.7% with R.S.D. values less than 1.0%. This method was successfully applied to the determination of contents of dictamine, obacunone and fraxitnellone in three commercial products of D. dasycarpus cortex. These results suggest that the developed HPLC method is simple, effective and could be readily utilized as a quality control method for commercial products.