• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.825-843
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• 2009

To prepare for agricultural droughts, the potential discharge to the water supply of irrigation facilities during drought periods is important. Using the MODSIM (Modified SIMYLD) model, water balance networks that consider irrigation facilities were designed for the Geum River Basin, and the potential discharge to the agricultural water supply of irrigation facilities were evaluated by running the model using data for 36 years (1967-2002). It was found that agricultural water deficiencies occurred during the drought years more than in the other years. The agricultural water deficiencies in 1994, 1995, and 2001, the representative drought years, were 745.8 million m$^3$, 661.1 million m$^3$, and 696.8 million m$^3$, respectively. The average potential discharge to the water supply of the sub-basin was 99.1 % in the cases of municipal and industrial water, and 84.4 % in the case of agricultural water. The potential discharge to the water supply in 1994, 1995, and 2001 were 74.8 %, 79.2 %, and 77.9 %, respectively, which are lower than those of the other years' sub-basin average. In the analysis of the contribution of each irrigation facility, the contributions of pumping stations and diversions were calculated as 32.5 %, and of culverts and wells, 4.0 %. During the drought periods, the pumping stations and diversions contributed to a certain level.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.121-128
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• 2008

Instream flows are defined as the stream flows needed to protect and preserve instream resources and values. They are supplied by the essential discharge for maintaining the channel. However, due to the lack of precipitation during the dry season, which is usually between the months of January and April, natural flows are not enough for the instream flows, thus leaving the dams at a shortage. In this paper, the method which will be discussed will show a physical way to improve water quality by the dilution of water that is supplied from a reservoir or dam, and how it is analyzed at the Han River basin. For the sake of this analysis, the basin has been divided into 33 catchments. Each catchment's natural flow has been simulated by SWAT-K, and the future water demand has been estimated using statistical data. It has also been assumed that the Han River basin has two large reservoirs(Chung-ju dam, and So-yang dam). The supply of potential discharge has been calculated using a case of water separately from each dam, as well as supply water from both dams.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.75-84
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• 2023

Many developing countries face challenges in estimating long-term discharge due to the lack of hydrological data for water supply planning, making it difficult to establish a rational water supply plan for decision-making on water distribution. The study area, the Bandung region in Indonesia, is experiencing rapid urbanization and population concentration, leading to a severe shortage of freshwater. The absence of water reservoir prediction methods has resulted in a water supply rate of approximately 20%. In this study, we aimed to propose an approach for predicting water reservoirs in developing countries by analyzing water safety and potential water supply using the MODSIM (Modified SIMYLD) network model. To assess the suitability of the MODSIM model, we applied the unit hydrograph method to calculate long-term discharge based on 19 years of discharge data (2002-2020) from the Pataruman observation station. The analysis confirmed alignment with the existing monthly optimal operation curve. The analysis of power plant capacity revealed a difference of approximately 0.30% to 0.50%, and the water intake safety at the Pataruman point showed 1.64% for Q95% flow and 0.47% for Q355 flow higher. Operational efficiency, compared to the existing reservoir optimal operation curve, was measured at around 1%, confirming the potential of using the MODSIM network model for water supply evaluation and the need for water supply facilities.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1712-1718
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• 2014

Experimental analysis according to the plasma actuator design variables was performed in order to verify the effects of sliding discharge plasma on aerodynamic drag reduction of a high-speed train. For the study, sliding discharge plasma actuator and high-frequency, high-voltage power supply were developed and experimented to figure out the best design variables for highest ionic wind velocity which could reduce the drag force. And then, 5% reduced-scale model of a high-speed train was built for wind tunnel test to verify it. From the results, it was confirmed that sliding discharge plasma had contribution to reduce the drag force and it had the potential to be applied to real-scale trains.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1174-1180
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• 2015

We investigate in this paper the radiated electromagnetic waves together with the discharge characteristics of Trichel pulse of negative DC corona discharge in air in pin-to-plate and wire-to-plate configurations. The feature of the current pulse and the frequency spectrum of the electromagnetic radiations were measured under various pressures and gas gaps. The results show that the repetition frequency and the amplitude of Trichel pulse current depend on the discharge conditions, but the rising time of the pulse relates only to the radius of needle or wire and keeps constant even if the other conditions (including the discharge current, the gas gap and the gas pressure) change. There exists the characterized spectrum of electromagnetic waves from negative corona discharge in Trichel pulse regime. These characterized radiations do not change their frequency at a given cathode geometry even if the averaged current, the gas gap or the air pressure changes, but the amplitude of radiations changes accordingly. The characterized electromagnetic radiations from Trichel pulse corona relate to the formation or the rising edge of current pulse. It confirms that the characterized radiations from Trichel pulse supply information of discharge system and provide a potential method for detecting charged targets.

• Journal of Korea Water Resources Association
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• v.41 no.11
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• pp.1143-1152
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• 2008

Korea is located in a monson area, so that 2/3 of precipitation is fallen down in rainy season and dry season has few rainfall. Also, water quality gets worse during dry season by shortage of water. In this paper, the method, which is a physical way to improve water quality by dilution through over supplied water from big reservoir or dam, is analyzed at Han-river basin. For the sake of the analysis, the basin is divided in 33 catchments and each catchments' natural flow is simulated by SWAT-K and the future water demand is estimated by using statistics data. It is considered that Han-river basin has two big reservoirs(Chung-ju dam, So-yang gang dam) and potential discharge by dam is calculated through case of supply water from each dam and supply water from both dams.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.161-169
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• 2015

A fire sprinkler system is very important to extinguish fire in the building. The sprinkler system initiates sprinkler discharge if the detection system identifies a developing fire and opens the pre-action valve. However, pre-action fire sprinkler systems mainly installed in the underground parking lot at the apartment complex do not properly operate at fire if the connection type of fire sprinkler systems does not properly installed and operated. This study identified the relationship between fire dispersion & damage and the connection type of water supply in the sprinkler system from many fire cases at the apartment complex in South Korea. In addition, this study also identified the water supply differences and characteristics between South Korea and foreign countries. The main purpose of this study is also to improve the water connection types in the sprinkler system that can reduce the potential failures of pre-action valve operation through electrical signal system. The study also suggests the improvement plan for water connection types in pre-action fire sprinkler system that can minimize potential failure of pre-action fire sprinkler system. The suggestions for revising the fire safe standard in South Korea includes letting the water supply pipe of sprinkler system water inlet connect to the second side of pre-action valve and the water flow device that can minimize potential failure of sprinkler system.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.9
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• pp.855-860
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• 2016

This study describes the design and implementation of digital Payload power supply. We materialized the interface of the PLDIU and power supply of a satellite bus, and minimized the potential for the occurrence of such erroneous operation circuit ESD through the WCA of the space environment. We designed a reliable power supply through simulation for a TID according to the vibration generated during the launch and space radiation environment, and found no problem in the function and performance through the test space environment after production.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.1
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• pp.1-13
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• 2006

The recent environmental protection issue has diminished the supply of sand for soft ground improvements so much that the prices of sand have shown a sudden rise. Plastic material is one of substitutes for sand material, but plastic is nonperishable and doubtable if it has potential environmental hormone disrupting substances. Moderate-priced natural fiber drain board made with coconut coir and jute filter are in the spotlight recently as an alternative material for sand and plastic drain board etc. Natural fiber drain has not only competitive price but also a characteristic of assimilation into the soils after finishing of its own function. Discharge capacity of the fiber drain board evaluated by triaxial type discharge capacity test was relatively lower than that of plastic drain board. Nevertheless, settlement and pore pressure dissipation behaviors of the fiber drain board and the plastic drain board which were installed in the clayey soil during the composite discharge capacity test were almost similar. It was also found that biodegradation of the fiber drain board was in progress until 18 month after installation in the clayey soil, but they had still enough engineering properties to use at field.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.72-80
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• 2020

A sea dike in the Yeongsan River estuary was constructed in 1981 to supply water and reclaim tidal flats for agriculture, separating the estuary into the freshwater and seawater zones. However, the sluice gates are frequently opened and freshwater is discharged in summer when more rainfall is recorded than other seasons, then converting the estuary to brackish water system. In this study, the direct effect of freshwater discharge was investigated by monitoring daily variation in water properties and phytoplankton size structure before and after the freshwater discharge events from 2013 to 2015. Freshwater discharge resulted in a sharp decrease in salinity and dissolved oxygen (DO) at surface water whereas it increased the turbidity of water column. However, salinity did not decrease sharply in 2014 when freshwater was discharged one day before the monitoring and salinity remained low prior to the monitoring. Levels of nutrients especially dissolved inorganic nitrogen (DIN) increased after the discharge and this contributed to potential limitation of nutrients such as P or Si rather than N in the estuary. Freshwater discharge also caused the changes in phytoplankton biomass (chlorophyll a) and size structure although their responses were different between years. The changes may affect growth of grazers and thus structure of marine food web by alternating food availability in the Yeongsan River estuary.