• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.78-78
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• 2020

The Se San and Srepok river basins (2S) are the two major tributaries of the Mekong River, both of which originate in the territory of Viet Nam and flow to Cambodia to meet at Stung treng with the Sekong river (originating in Lao PDR) to form the 3S river basin before joining the Mekong mainstream. In the territory of Viet Nam, the 2S river basins are located in the Central Highlands including 5 provinces, arranged by geographical location from north to south namely Kon Tum, Gia Lai, Dak Lak, Dak Nong and Lam Dong. This is a region with a very important strategic position in terms of economy, politics and defense for the whole country with many potential advantages for economic development. However, the limited and vulnerable basin water resources are under the pressure of socio-economic development in line with increasing water demands for various sectors. In order to overcome the water management challenges, a long-term water resources planning has conducted to support the 2S River Basin Committee (RBC) in effective planning and operation as part of the WB Mekong-Integrated Water Resources Management (IWRM) Project. This paper introduces the outline and progress of the river basin planning using analytical DSS toolkits to analyze, evaluate and formulate the planning options.

• Journal of Korean Society of Disaster and Security
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• v.7 no.1
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• pp.9-16
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• 2014

In the high water pressure construction conditions, it is important that the failures and damages occurrence in the neighboring ground and impermeable prevention methods (design and construction) for a inflow of seawater into structures. Grouting construction markets include a subway construction, a railway construction, a mountain tunnel construction, a new & reinforced construction of river & reservoir levee with big budget per every years. but, there are economic loss about design and construction management parts because that management criteria is not accurate but depends on experiences. Even though grouting technology are using vitally in the major constructions of national levels, it is still serious about the low-reliability problems and the no-criteria problems. therefor the purpose of this study is that provides the fundamental research about the neo-grouting technology for the decreasing of ground disaster in a high water pressure conditions.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.149-157
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• 2008

The reduction of leakage is a major issue of the South Korea water industry. The inclusion of pressure dependent leakage terms in network analysis allows the application of optimization techniques to identify the most effective means of reducing water leakage in distribution networks. This paper proposes a method to find optimal setting and location of control valve for reducing leakage efficiently. The proposed search method differs from previous methods for addressing optimal valve location problem and improves the GA simulation time with guaranteeing for getting the global optimal solution. The strength of this method has been demonstrated by means of case studies. This allows the procedure of optimization to be more robust and computational efficient.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.160-160
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• 2019

Water is a limited source that needs to be properly managed and distributed to the ever-growing population of the world. Rapid urbanization and development have increased the overall water demand of the world drastically. However, there is loss of billions of liters of water every year due to leakages in water distribution systems. Such water loss means significant financial loss for the utilities as well. World bank estimates a loss of $14 billion annually from wasted water. To address these issues and for the development of efficient and reliable leakage management techniques, high efforts have been made by the researchers and engineers. Over the past decade, various techniques and technologies have been developed for leakage management and leak detection. These include ideas such as pressure management in water distribution networks, use of Advanced Metering Infrastructure, use of machine learning algorithms, etc. For leakage detection, techniques such as acoustic technique, and in recent yeats transient test-based techniques have become popular. Smart Water Grid uses two-way real time network monitoring by utilizing sensors and devices in the water distribution system. Hence, valuable real time data of the water distribution network can be collected. Best results and outcomes may be produced by proper utilization of the collected data in unison with advanced detection and management techniques. Long term reduction in Non Revenue Water can be achieved by detecting, localizing and repairing leakages as quickly and as efficiently as possible. However, there are still numerous challenges to be met and future research works to be conducted in this field.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.185-191
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• 2014

In this study safety distance was investigated for small-scale LNG storage facilities in order to provide basic data for safety. The results are as follows; (1) For explosion pressure criteria, current criteria are reasonable, but water spray system should be recommended to LNG storage tank to ensure safety. (2) For criteria based on the results of the quantitative risk assessment, criteria applied to people are $5kW/m^2$ for radiation, LFL for dispersion, and 7kPa for explosion pressure. And criteria applied to facility are $37.5kW/m^2$ for radiation and 20 kPa for explosion pressure.

• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.87-100
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• 2008

The alternative evaluation index (AEI) is developed and applied to determine the priorities of some options for integrated watershed management. Based on the results of continuous simulation model, AEIs of some feasible alternatives are calculated using multicriteria decision making techniques and sustainability evaluation model, DPSIR (Drivers-Pressure-State-Impact-Response).

• International Journal of Ocean System Engineering
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• v.2 no.2
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• pp.71-81
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• 2012

Several methods have been proposed to control the sedimentation process. These include catchment management, flushing, sluicing, density current venting, and dredging. Flushing is used to erode previously deposited sediments. In pressurized flushing, the sediment in the vicinity of the outlet openings is scoured and a funnel shaped crater is created. In this study, the effect of localized vibrations in the sediment layers on the dimensions of the flushing cone was investigated experimentally. For this purpose, experiments were carried out with two bottom outlet diameters, five discharge releases for each desired water depth, and one water depth above the center of the bottom outlets. The results indicate that the volume and dimensions of the flushing cone are strongly affected by localized vibrations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.3
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• pp.251-257
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• 2000

District heating and cooling systems offer highly efficient energy utilization and maintenance by centralizing heat management. More pumping power, however, is required because the water has to travel long distance from heat source to the users. In the present study, a trace of drag reduction additives is added to the District Cooling system to achieve a significant drag reduction and save pumping power. Water-soluble polymers, surfactants, and environment-friendly degradable polymers are used as effective drag reducing additives. Time dependent percent drag reductions are compared for various additive solutions at 100 wppm concentration for different water velocity. Without as an anionic surfactant, copolymer was most effective in percent drag reduction. It is found that there exists an optimal condition when copolymer is mixed with SDS. An environment-friendly degradable polymer, xanthan gum, is found to be a significant drag reduction additive. Ice slurry systems, can give less pressure drops compared with chilled water system for certain condtions. Drag reduction additives were also effective for the ice slurry system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.314-316
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• 2022

Instrumentation device to the amount of water used by the user is a water meter by measuring management stability is necessary. But with the onset of winter to meter water was ice inside the phase change and about 9 % and increase the volume of the meter is damaged. The existing protection bleed water meter freeze protection technology into three great bootong, supplying the heat insulation inside the external protection, water metering for water meter in the freeze protection will be divided into installing the device. Not see how far the structure for the commercialization of new technology-based products and aims to develop technologies that do not require an external power supply. Thus, freeze more vulnerable by internal pressure of the interpretation applied to a water meter in temperatures below zero internal pressure to confirm the area of preventing damage and freeze protection that can reduce the effect is superior to develop a water meter.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.120-125
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• 2020

75 tonf liquid rocket engine combustion test was performed at Naro space center Engine Combustion Test Facility for KSLV-II. A gradual pressure drop was observed during off-design combustion test turbopump inlet condition using cooled kerosene at 271 K. It was found that the water content inside kerosene could cause pressure drop at 40 ㎛ grade filter through the water contests analysis of kerosene, kerosene cooling test and dehydration of kerosene.