• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1248-1252
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• 1999

To provide electricity power of good quality, it is essential to establish generation of electricity plan in electric power system based on accurate power-demand prediction and cope with changes of power-need fluctuating constantly. The role of hydraulic-power generation of electricity in electric power system is of importance because responding to electric power-demand counts or reservoir-type hydraulic-power generation of electricity which is designed for additional load in electric power system. So hydraulic-power generation of electricity must have fast start reserve. But the amount of water, resources of reservoir-type hydraulic-power generation of electricity is restricted and multi-used, so the scheduling of management by exact forecasting the amount of water is critical. That is why efficient hydraulic-power generation of electricity makes a main role on pumping up the utility of energy and water resource. This thesis introduced the example of optimal generation of electricity plan establishment which is used in managing reservoir-type hydraulic-power generation of electricity.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.457-462
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• 2009

In this paper we suggest optimal positioning algorithm for DER(distributed energy resource)s near ocean side by using Newton-Rhapson load flow calculation. By installing DERs within urban area, electric power can be effectively transmitted to each loads without constructing additional large scale power stations and transmission lines. Therefore, DERs have attracted worldwide attention as urban area energy sources. However, there are quite a few studies for estimation of power loss due to DERs' location change within urban area Hence, in this study, an optimal positioning scheme for DERs is proposed in order to minimizing electrical power loss.

• Environmental and Resource Economics Review
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• v.17 no.2
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• pp.419-455
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• 2008

This paper analyses the Night Thermal-storage Power Service(NTPS) from the perspective of sustainability. It investigates the economic, environmental and social aspects of NTPS, thereby reveals that NTPS triggers the inefficient use of fuel, the increase of carbon dioxide emission and the increase of cross subsidy between consumers. This paper also analyses NTPS from the perspective of energy security. It investigates how NTPS makes LNG demand volatile in winter, thus threatens our energy security. According to the analysis, NTPS directly violates two basic principles of national energy policy; Sustainability and Energy Security. To solve these problems, not only the harmonized adjustment of Heating Oil Tax and Electric Power Rates is needed to curb the rapier increase of NTPS, but also another separate policy is necessary for converting the electric heating system based on NTPS into the one based on Heating Oil.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.39-44
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• 2010

In LTE-Advanced systems, every sector uses the entire range of the frequency resource, and when the UEs are located at a cell edge, user throughputs degrade due to the interferences from the adjacent cells. In this paper, we propose a combined scheme for inter-cell interference avoidance and power control. In the proposed algorithm, the sectors consist of the right edge, the left edge and the center for resource allocation and we control the transmission power to improve the user throughputs at the edge of each cell. Using a system level simulation, we analyze low 5th percentile and average user throughputs of the UEs who are located the cell, center and edge when the inter-cell interference avoidance and the power control are combined.

• Environmental and Resource Economics Review
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• v.29 no.4
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• pp.443-468
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• 2020

Broad effects of fuel-transition in all type of ground transportation have occurred with the help of the advances in electric vehicle (EV) technologies and the increases in EV supply. This research estimates the economic benefit of air environmental improvements, which results from the fuel-transition of high-mileage business cars(taxies) in metropolis. If we consider power production sector for EV operation, some air pollutants will be produced. In this respect, this research takes both the mixture of power sources in power production level and the driving pattern of business cars into account when investigating the economic benefit in air environment resulted from the fuel-transition of business cars(taxies). According to our results, the business cars' fuel transition from LPG to electricity brings about 21.5￦/km (8.6million won/year) of economic benefit in air environment. These results emphasize the necessity and appropriateness of public polices for expanding power production with renewable energies and facilitating EV distribution.

• Environmental and Resource Economics Review
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• v.30 no.4
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• pp.627-648
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• 2021

The fine-dust season management system refers to the policy of implementing enhanced reduction measures in transportation, power, business and living sectors in winter, when fine dust levels are high. The fine dust season management system is a regulatory policy that causes social costs and transfers to various economic players. Equity is an important issue for the cost burden. Therefore, in this study, the cost of each power generator was analyzed using the coal power generation reduction amount of each power generator to verify that the cost of the power sector is evenly distributed. In particular, the effect of the fine dust season management system on coal power generation of power generators was analyzed by applying a synthetic control method that can identify the time-variable effect of the policy. It was confirmed that the fine dust season management system reduced volume of fuel and power generation in coal power plants, resulting in an increase in the cost of the power generation sector, even considering the effect of some power demand due to the COVID-19 crisis. However, it could be seen that these costs were not distributed equally among the generators, and that they were more costly to the specific generators.Social costs incurred by fine dust season management need to be improved so that stakeholders are equally burdened.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.95-103
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• 2018

As a guideline for desulfurization and dehumidification pretreatment facility for optimizing utilization of biogas, the $H_2S$ concentration is set at 150 % which can be treated with iron salts, dehumidification is the optimum value for generator operation, and the relative humidity applied at the utilization of biogas in EU is set at 60 %. We have set up the generator facility guidelines to optimize utilization of biogas. The appropriate amount of biogas should be at least 90 % of the total gas generation, and the capacity of generator facility should be set at 20~30 %. In order to equalize the pressure of the incoming gas the generator, a gas equalization tank should be installed and the generator room average temperature should be kept at $45^{\circ}C$ or less. Since the gas is not produced at a certain methane concentration in the digester, the efficiency is lowered. Therefore, it is required to install an air fuel ratio control system according to the change in methane concentration. Therefore, it is necessary to compensate for the disadvantages of biogasification facilities of organic waste resources and optimize utilization of biogas and improve operation of facilities. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure), investigate the facilities problem and propose design, operation guidelines such as pre-treatment facilities and generators.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1225-1228
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• 2011

This paper presents an advanced energy saving algorithm in building. It is important to aggregate a various demand side resource which is controllable on demand response environment. Previous demand side algorithm for building is restricted on peak power. In this paper, we suggest duty cycle algorithm for AHU on demand response to reduce the quantity of building power consumption. The test results show that the proposed algorithm is very effective.

• Korean Journal of Medicinal Crop Science
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• v.27 no.6
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• pp.412-418
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• 2019

Background: Previously, studies have observed that the leaf extract of Cotoneaster wilsonii Nakai has potent antioxidant and anti-inflammatory activites. Therefore, further research was conducted to separate the active antioxidant and anti-inflammatory compounds in the leaf of the C. wilsonii. Methods and Results: The anti-oxidant effects were evaluated by analyzing the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, estimating the totla phenolic content (TPC) and total flavonoid content (TFC), and using reducing power assay method. The ethyl acetate (EtOAc) fraction demonstrated the highest DPPH radical scavenging activity (IC₅₀; 9.69 ㎍/㎖), and the highest TPC and TFC (345.98 mg·GAE/g, and 74.23 mg·QE/g). Moreover, it indicated the highest effects on nitric oxide production. Therefore, the active compound was separated using the EtOAc fraction, determined on the basis of spectral data, and identified as (+)-catechin. Conclusions: The first compound separated was made from the leaf of C. wilsonii was (+)-catechin, which produced potent anti-oxidant and anti-inflammatory effects.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.784-795
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• 2016

In this paper, we investigate the resource allocation problem in time-varying heterogeneous wireless networks (HetNet) with multi-homing user equipments (UE). The stochastic optimization model is employed to maximize the network utility, which is defined as the difference between the HetNet's throughput and the total energy consumption cost. In harmony with the hierarchical architecture of HetNet, the problem of stochastic optimization of resource allocation is decomposed into two subproblems by the Lyapunov optimization theory, associated with the flow control in transport layer and the power allocation in physical (PHY) layer, respectively. For avoiding the signaling overhead, outdated dynamic information, and scalability issues, the distributed resource allocation method is developed for solving the two subproblems based on the primal-dual decomposition theory. After that, the adaptive resource allocation algorithm is developed to accommodate the timevarying wireless network only according to the current network state information, i.e. the queue state information (QSI) at radio access networks (RAN) and the channel state information (CSI) of RANs-UE links. The tradeoff between network utility and delay is derived, where the increase of delay is approximately linear in V and the increase of network utility is at the speed of 1/V with a control parameter V. Extensive simulations are presented to show the effectiveness of our proposed scheme.