• Journal of Environmental Science International
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• v.13 no.12
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• pp.1041-1048
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• 2004

In this study the results of optimal water supply analysis by operating constraints of reservoirs during drought period are as follows. During drought period, water supply reliability is possible about $97\~61{\%}$ by CASE 1-CASE 5. Water supply reliability is possible about $97.3{\%}$ in case of the Andong dam and $87.7{\%}$ in case of the Imha dam by CASE 3. Also, under the constraints of CASE 4, water supply reliability is possible about $87.5{\%}$ in case of the Andong dam and $73.3{\%}$ in case of the Imha dam. The reason what low of available water supply ratio is decreased inflow of Imha dam. When compare standard deviation of average storage with standard deviation of storage, stable storage can be secured during successive drought period. And it also can minimize shortage of water during drought. therefore, it is impossible that reservoir supply sufficient water but change of operating condition is better than pervious on that followed by full reservoir level. It is need that the study for optimal water supply during drought period has to be continued.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.163-163
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• 2019

The rapidly growing global population increases the awareness of water, energy, and food security worldwide. The concept of Water, Energy, and Food nexus (hereafter, WEF nexus) has been widely introduced as a new resources management concept that integrate the water, energy, and food in a single management framework. Recently, WEF nexus analyzes not only the interconnections among the resources, but also considers the external factors (such as environment, climate change, policy, finance, etc) to enhance the resources sustainability by proper understanding of their relations. A nation-level resources management is quite complex task since multiple regions (e.g., watersheds, cities, and counties) with different characteristics are spatially interconnected and transfer the resources each other. This study proposes a multiple region WEF nexus simulation and transfer model. The model is equipped with three simulation modules, such as local nexus simulation module, regional resources transfer module, and optimal investment planning module. The model intends to determine an optimal capital investment plan (CIP), such as build-up of power plants, water/waste water treatment plants, farmland development and to determine W-E-F import/export decisions among areas. The objective is to maximize overall resources sustainability while minimize financial cost. For demonstration, the proposed model is applied to a semi-hypothetical study area with three different characterized cities. It is expected the model can be used as a decision support tool for a long-term resources management planning process.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.6
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• pp.1477-1484
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• 2006

This experimental study was designed to investigate the effects of Acanthopanax sessiliflorus $S_{EEM}$ extracts following gamma-ray irradiation on the change of weight, the serum total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride, free fatty acid, total lipid, phospholipid level in obese mice induced by high fat diet, and the change of regional cerebral blood flow (rCBF) and blood pressure (BP) in normal rats. Experimental materials were as follows ; 10AS was the bark powder of Acanthopanax sessiliflorus $S_{EEM}$ stems which was exposed in 10 kGy electron beam, 10AS was the bark powder of Acanthopanax sessiliflorus $S_{EEM}$ roots which was exposed in 10 kGy electron beam, 100S was the bark powder of Acanthopanax sessiliflorus $S_{EEM}$ stems which was exposed in 100 kGy electron beam, Experimental groups were as follows ; Normal group was fed with normal diet and administered with distilled water during 5 weeks, Control group was fed with high fat diet and administered with distilled water during 5 weeks, Sample A group was fed with high fat diet and administered with 10AS of 300 mg/kg/mouse/day during 5 weeks, Sample B group was fed with high fat diet and administered with 10AR of 300 mg/kg/mouse/day during 5 weeks, Sample C group was fed with high fat diet and administered with 100AS of 300 mg/kg/mouse/day during 5 weeks. The results were as follows ; Sample A group, Sample B group and Sample C group were significantly decreased body weight and the serum LDL-cholesterol, triglyceride, total lipid level in comparison with Control group. Sample A group, Sample B group and Sample C group were significantly increased the serum HDL-cholesterol level in comparison with Control group. Sample B group and Sample C group were significantly decreased the serum total cholesterol, free fatty acid and phospholipid level in comparison with Control group. This results were suggested that all experimental materials were able to be used for the obesity. 10AS did not changed rCBF and MABP in a dose-dependent manner. 10AR significantly increased rCBR in a dose-dependent manner, and BP did not change in a dose-dependent manner. 100AS decreased rCBF and BP in a dose-dependent manner. This results were suggested that 10 AR significantly increased rCBF by dilating pial arterial diameter. According to above results, the authors suggested that 10AR was able to be used for the obesity and ischemic disease.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.3-14
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• 2004

This study was conducted to assess the possibility of the field application of the iceharbor-type precast fishway. When overflow depth of weir is 4.0 cm in model fishway, upper part velocities appear appropriate for upstream migration of fish and the lowest overflow wall (right line) in lower part has shown velocity distribution more or less inadequate for upstream migration. Except that right line, left and middle line revealed that velocities are appropriate for upstream migration of fish. Therefore, we concluded that this fishway owing to be not broad growth width of overflow velocities according to increasing discharges can correspond to variation of water level. Also We consider that various velocities in fishway were effective, because slow velocity line can guide flow for upstream migration. For low flow, the arrangement of different crest level or each overflow part (higher left, middle and lower right, or lower left, middle and higher right) was more effactive than unform crert level. Hole plays an important role as migration pass during drought and flood flow. Therefore, We concluded that this fishway can cope with water depth variation by various overflow wall height change and raise the field applicability with better performance hydraulically and structurally.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.3
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• pp.321-328
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• 1998

When we control the level of the steam generator in the nuclear power plants, a swell and shrink arises from many disturbances such as feed water rate, feed water temperature, main steam flow rate, and coolant temperature. If we use the conventional type of PI controller in this system, we will not have stability during controlling at lower power, the removal function of disturbances, and a load follow-up control effectively. In this paper, we study the application of a 2-Degree of Freedom(2-DOF) PID controller to the level control of the steam. generator of nuclear power plants through the simulation and the experimental steam generator. We use the parameters $\alpha$, $\beta$, $\gamma$ of the 2-DOF PID controller for the removal of disturbances and the parameters Kp,Ti,Td of the conventional type of PID controller for controlling setpoint. The back-propagation learning algorithm of neural network is used for tuning the 2-DOF PID controller. We can find satisfactory results of the removal of the disturbances and the tracking function in the change of setpoint through the simulation and experimental steam generator.

• Journal of Korea Water Resources Association
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• v.57 no.7
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• pp.471-479
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• 2024

Flood damage is becoming more serious due to the heavy rainfall caused by climate change. Physically based hydrological models have been utilized to predict stream water level variability and provide flood forecasting. Recently, hydrological simulations using machine learning and deep learning algorithms based on nonlinear relationships between hydrological data have been getting attention. In this study, the Long Short-Term Memory (LSTM) algorithm is used to predict the water level of the Seomjin River watershed. In addition, Climate Prediction Center morphing method (CMORPH)-based gridded precipitation data is applied as input data for the algorithm to overcome for the limitations of ground data. The water level prediction results of the LSTM algorithm coupling with the CMORPH data showed that the mean CC was 0.98, RMSE was 0.07 m, and NSE was 0.97. It is expected that deep learning and remote data can be used together to overcome for the shortcomings of ground observation data and to obtain reliable prediction results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.3
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• pp.215-225
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• 2011

During the past decade, the performance-based design method of caisson breakwaters has been developed, which allows a certain damage while maintaining the function of the structure. However, the existing method does not consider the changing coastal environment due to climate change impacts so that the stability of the structure is not guaranteed over the lifetime of the structure. In this paper, a time-dependent performance-based design method is developed, which is able to estimate the expected sliding distance and the probability of failure of a caisson breakwater considering the influence of sea level rise and wave height increase due to climate change. Especially, time-dependent probability of failure is calculated by considering the sea level rise and wave height increase as a function of time. The developed method was applied to the East Breakwater of the Hitachinaka Port which is located on the east coast of Japan. It was shown that the influence of wave height increase is much greater than that of sea level rise, because the magnitude of sea level rise is negligibly small compared with the water depth at the breakwater site. Moreover, investigation was made for the change of caisson width due to climate change impacts, which is the main concern of harbor engineers. The longer the structure lifetime, the greater was the increase of caisson width. The required increase of caisson width of the Hitachinaka breakwater whose width is 22 m at present was about 0.5 m and 1.5 m respectively for parabolic and linear wave height increase due to climate change.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.177-182
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• 1989

The plant height, shoot numbers and dry matter weight in both bulrush and rice were increased by high level of nitrogen fertilizer and especially the dry matter weights in both species were sharply increased by high level of nitrogen fertilizer. The plant height, dry matter weight in rice, and shoot, and dry matter weight in bulrush were increased by high level of phosphorus fertilizer. The deficient symptom disappeared with change of low level into high level phosphorus in rice. The plant height, dry matter weight and shoot numbers in rice and bulrush were increased by high level of potassium fertilizer. In the inter-specific competition in bulrush according to various water levels, the plant heights in both species elongated longer with deep water levels, and the plant height and dry matter weight in bulrush were more sharply decreased than in rice by deep water levels. The shoot numbers and dry matter weight were critically dropped above 6-8 cm water level. In case of the shoot numbers for light source, in both species were more decreased in mixed culture than each monoculture. The exserted shoot length and weight in bulrush were larger than those in rice. The shaded shoot dry weight was more decreased in mixed culture than in each monoculture, and the decrement was larger in bulrush than in rice.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.753-766
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• 2014

The future mean sea level rise (MSLR) due to climate change in major harbors of Korean Peninsula has been estimated by some statistical methods in this article. Firstly, Mann-Kendall non-parametric trend test to find some trend in the observed long-term tidal data has been performed and also Bayesian change point analysis has been used also to detect the location of change points and their magnitude quantitatively. Especially, in this study, the results from Bayesian change point analysis have been applied to combine 4 future MSLR scenario projections with local MSLR data at 5 tidal gauges. This proposed procedure including Bayesian change point analysis results can improve the step for the determination of starting years of future MLSR scenario projections with 18.6-year lunar node tidal cycle and effectively consider local characteristics at each gauge. The final results by the proposed procedure in this study have shown that the future MSLR in Jeju region (Jeju tidal gauge) is in the largest increment and also the future MSLRs in Western region (Boryeong tidal gauge) and Southern region (Busan tidal gauge) are in the second largest one. Finally, it has been shown that the future MSLRs in Southern region (Yeosu tidal gauge) and Eastern region (Sokcho tidal gauge) seem to be in the relatively smallest growth among 5 gauges.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.315-315
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• 2017

In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.