• Journal of Korean Society of Water and Wastewater
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• v.34 no.5
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• pp.335-344
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• 2020

Due to global climate change, mega-droughts have occurred frequently. Since long-term droughts make it difficult to secure the water resources, water supply needs to be restricted in a reasonable manner. In the event of limited water supply, the waterworks need to develop a restricted water supply strategy. This study showed that analyzing daily water supply could be used to respond to the first stage of a drought. According to an analysis of Korea's major water authorities, there was about 7~21% of room for daily minimum water supply in case of a drought. Restricting the water supply by lowering pressure is a good strategy for local water authorities with high water leakage rate since leakage is inversely dependent with pressure. For this method, it is necessary to quantify water deficiency and pressure at each node using a simulation. Since DDA-based software is not possible to predict changes in demand at nodes with pressure reduction, WaterGEMS, a PDA software, was used to quantitatively predict water shortages and pressures at each node. Locations where water is deficient need to install booster pumps or to be dispatched with water tank truck and bottled water. Without these support, lowering pressure could not be an option for water works. This paper suggests a method for waterworks to plan a drought by lowering pressure to restrict water supply using daily water supply analysis and PDA based simulation.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.339-362
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• 2018

In this paper, we simulate the contribution of an increasing renewable energy to demands for fossil fuels and power supply price by estimating a cost function for the Korean electric power generation sector. Since the renewable energy is a composite input, it is not feasible to compute the price index for renewable energy due to data limit. We estimate a restricted cost function, which is derived by minimizing the costs of fossil fuels conditional on the quantity of renewable energy set to its optimal level, jointly with supply relation. In particular, derivation of the shadow price of renewable energy would make it possible to analyze potential costs incurred by power plants.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.1-11
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• 2014

The water distribution system should be invariably operated on continuous pattern for 24 hours a day. Occasionally, it is not practically possible to operate for 24 hours due to water shortage or financial constraints. Therefore an intermittent water supply is unavoidable in water shortage area and developing countries. But the intermittent water supply can introduce large pressure forces and rapid fluid accelerations into a water supply network. These disturbances may result in new pipe failure, leakage and secondary contamination. This paper proposed an improvement methodology to prevent the disturbances by intermittent water supply. For the study, the hydraulic variation of intermittent flow in water distribution system was measured and analyzed in the field by comparing with simulation of hydraulic model. Installations of control valves such as, pressure reducing and sustaining and air valves were employed for pressure and flow control. The effectiveness of the methods are presented by comparing hydraulic conditions before and after introducing the proposed solutions.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.243-246
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• 2003

A radical environmental change of enterprise and varieties of customer needs demand that the value-added activities of enterprise should be restructured and coordinated. But it is not sufficient that the reengineering processes are restricted withen a firm, so the value-added processes should be expanded into intercompany. The integrated organizational structure between enterprises refer to supply chain network. In this paper we present characteristics, structure concepts, and axiomatic model of supply chain network.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.169-172
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• 2003

A design power supply for car audio installation which uses SCR phase control method is able to get output DC 15[V]-100[A] in US wall outlet restricted to input AC 120[V]-15[A]. As the power supply for car audio is tested, output is DC 15[V]-100[A] in ripple voltage 110[mV].

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.67-76
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• 2003

The principal operation rule of irrigation reservoir is to accelerate the water use and supply water actively when water is sufficient, and to restrict water use and supply water deficiently in order not to stop the irrigation activity when water is scarce. In drought seasons. water should be saved in order to keep the reservoir not to be dried up during the irrigation season. It is important to know how much water should be saved, depending on the rice-growing season and water storage volume. For the drought control of irrigation reservoirs. the rotational irrigation scheduling in paddy with the operation rule curve developed in this study could be utilized as a software program to install TM/TC system for irrigation water supply by automation facilities.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.2
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• pp.75-80
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• 2002

The severity of drought in (the) irrigation reservoir could be evaluated by the accumulative rainfall method, soil moisture content method, storage ratio method, and water supply restricted intensity method, etc. The storage ratio method would be the most reliable one for irrigation reservoir. The pattern of drought might be forecast with the most similar pattern of accumulative rainfall and/or storage ratio out of the file of past operation history.

• The Korean Journal of Ecology
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• v.9 no.1
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• pp.19-24
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• 1986

Effects of temperature, pH, light-and-dark and degree of oxygen supply on germination of Papaver somniferum L. seeds were investigated. The optimum temperature of the germination was 2$0^{\circ}C$, but the germination was decreased as temperatures changed to the upper and lower. The largest elongation of both radicle and hypocotyl also occurred at 2$0^{\circ}C$. The best germination occurred at pH 7 but this decreased suddenly the above and below of that pH value. Although no effect of light-and-dark on the germination was, this was restricted under limited. oxyten supply in terms of underwater germination as compared with abovewater one.

• Korean Journal of Poultry Science
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• v.8 no.1
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• pp.25-30
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• 1981

This study was conducted to find the method that the least-cost formula can be determined thus allowing a better keeping of raw material supplies under the constraints having to be used some raw materials that are either in limited supply or for other reason in restricted use. In this study, it was considered that three kinds of feed were produced under limited supply of six kinds of raw materials, and data for the analysis were collected from a feed mill in southern part of Korea. According to the result of this study, it was proved better to determine the least-cost formula as the multi-mix problem than as the simple least-cost problem when more than two kinds of feed were produced wilt limited supply of raw materials.

• IE interfaces
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• v.18 no.1
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• pp.63-72
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• 2005

In this paper, we present a distribution planning method for a supply chain. Like a typical distribution network of manufacturing firms, we have the form of arborescence. To consider more realistic situation, we investigated that an outside supplier has limited capacity. The customer demands are given in deterministic form in finite number of discrete time periods. In this environment, we attempt to minimize the total costs, which is the sum of inventory holding and backorder costs over the distribution network during the planning horizon. To make the best of the restricted capacity, we propose the look-ahead feature. For looking ahead, we convert this problem into a single machine scheduling problem and utilize tabu search approach to solve it. Numerous simulation tests have shown that the proposed algorithm performs quite well.