• KEPCO Journal on Electric Power and Energy
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• 제5권2호
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• pp.113-120
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• 2019

We have developed 1 kW-class PEMFC-battery hybrid system independently powering to the building, through the process of system design, current load characteristics analysis, power system configuration for demonstration site and performance evaluation. In order to use the fuel cell and battery as the hybrid type, a control technology for the charging/discharging decision and charging speed of the battery is required rather than using fuel cell. Also output power distribution between PEMFC and the battery is a core of energy management technology. It is confirmed that it is possible to supply independently 1kW powering the building to ensure optimal energy management through the power control experiment of the hybrid system.

• KEPCO Journal on Electric Power and Energy
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• 제4권2호
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• pp.107-114
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• 2018

In recent years, ESS (Energy Storage System) has been widely used in various parts of a power system. Especially, due to its fast response time and high ramp rate, ESS is known to play an important role in regulating grid frequency and providing rotational inertia. As the number of installed and commercially operating ESSs increases, the reliability becomes an important issue. This paper introduces control schemes and presents its test method for grid-connected ESS for primary frequency regulation. The test method allows to verify the control operation in the individual operation mode and state. A validation of the method through actual ESS test in a electrical substation is presented in the case study section.

• KEPCO Journal on Electric Power and Energy
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• 제6권4호
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• pp.399-404
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• 2020

There are many attempts to apply AI technology to diagnose facilities or improve the work efficiency of the power industry. The emergence of new machine learning technologies, such as deep learning, is accelerating the digital transformation of the power sector. The problem is that traditional power systems face security risks when adopting state-of-the-art AI systems. This adoption has convergence characteristics and reveals new cybersecurity threats and vulnerabilities to the power system. This paper deals with the security measures and implementations of the power system using machine learning. Through building a commercial facility operations forecasting system using machine learning technology utilizing power big data, this paper identifies and addresses security vulnerabilities that must compensated to protect customer information and power system safety. Furthermore, it provides security guidelines by generalizing security measures to be considered when applying AI.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 전기설비전문위원
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• pp.33-36
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• 2009

In this paper, evaluation of physical properties was made for dielectric relaxation phenomena by the detection of the surface pressures and displacements current on the monolayer films of fatty acid monomolecular Arachidic Acid, Stearic Acid using compressing velocity. LB(Langmuir-Blodgett) thin films were manufacture by detecting deposition for the accumulation and the current was measured after the electric bias was applied across the manufactured MIM device. The physicochemical properties of the fatty acid monomolecular Arachidic Acid, Stearic Acid films surface structure has been studied by AFM. We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is gas state, liquid state, solid state. Formation that prevent when gas phase state and liquid phase state measure but could know organic matter that molecules form equal and stable film when molecules were not distributed evenly, and accumulated in solid state only.

• Asian Journal of Innovation and Policy
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• 제12권3호
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• pp.345-362
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• 2023

As the widespread adoption and proliferation of electric vehicles continue, the secondary battery market is experiencing rapid growth. However, lithium-ion batteries, which constitute a majority of secondary batteries, present high risks of fire and explosion. Solid-state batteries are thus garnering attention as the next-generation batteries since they eliminate fire hazards and significantly reduce the risk of explosions. Against this background, the study aimed to analyze research trends and provide insights by examining 2,927 domestic papers related to solid-state batteries over the past decade (2013-2022). Specifically, we used topic modeling to extract major keywords associated with solid-state batteries research and to explore the network characteristics across major topics. The changes in research on solid-state batteries were analyzed in-depth by calculating topic dominance by year. The findings provide an overview of the emerging trends in domestic solid-state battery research, and might serve as a valuable reference in shaping long-term research directions.

• 한국철도학회논문집
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• 제3권4호
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• pp.219-228
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• 2000

This paper presents an advanced approach to simulate AC electric railway system in steady-state. The algorithm consists of two parts. One is circuit modeling of elements of electric railway system, the other is an analysis on electric circuit. The modeling procedure has two steps, in the first step, proposed is the modeling method which is considered to be an internal impedance of the autotransformers and mutual impedances between the feeding systems. For the load(locomotives) modeling which is the second step, improved results are obtained as application to the proposed constant power model compared with constant impedance model. In the analysis on electric circuit, a generalized analysis method using the loop equation has been proposed and there is no limit in the number of trains between the ATs. In addition, the computer simulation by the proposed model was practiced. Simulation result seems very reasonable. It is therefore concluded that techniques for the electric circuit modeling and analysis have been established. Accuracy of the techniques will be further investigated.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1037-1040
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• 2009

Using much most electricity electric resistivity survey by nondestructiveness inquiry enforcement design of country base equipment business and facilities preservation administration dimension electric resistivity survey sends and cause much effects in survey believability by electricity medium of survey personality survey contiguity that grasp base special quality by potential difference flowing current artificially in base. Is item that enforce in most in-suite although when make electric resistivity survey until present, electricity medium or effect research by electricity origination was gone much. There is shortcoming that must be difficult to know correct underground utilities establishment state in-suite in this research and do comparison examination running parallel drilling investigation to heighten believability of electric resistivity survey. Did to dam that censure data that regulate grading from construction and is censure construction which can know correctly interior base situation comparatively to electricity medium of interior and electricity eruption won of contiguity and base condition (base rock).

• 한국자동차공학회논문집
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• 제21권2호
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• pp.136-145
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• 2013

It is very important to determine specifications of components included in the drive-train of vehicles at the initial design stage. In this study, component sizing process and performance analysis for Extended-Range Electric Vehicles (E-REV) are discussed based on the foundation of determined system configuration and performance target. This process shows sizing results of an electric driving motor, a final drive gear ratio and a battery capacity for target performance including All Electric Range (AER) limit. For E-REV driving mode, the constant output power of a Gen-set (Engine+Generator) is analyzed in order to sustain State of Charge (SOC) of the battery system.

• 한국광학회지
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• 제17권3호
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• pp.262-267
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• 2006

효율적인 PPLN 제작을 위하여 DC 전계를 인가하면서 $LiNbO_3$에 인가되는 전압 및 전류를 실시간으로 측정할 수 있는 실험 장치를 제안하였다. 제안된 실험 장치를 사용함으로써 PPLN의 분극반전에 필요한 충분한 전하량을 공급하기 위한 전계인가시간을 수초 단위로 증가시킬 수 있어 $LiNbO_3$에 주입되는 전하량의 조절을 용이하게 할 수 있었다. 또한 PPLN의 분극반전 과정을 단계별로 분류하고 각 단계별 실험결과를 바탕으로 분석함으로써 최적의 PPLN 제작조건을 구할 수 있었다.

• 제어로봇시스템학회논문지
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• 제6권8호
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• pp.672-681
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• 2000

Based on the dynamic anti-windup strategy a novel control methodology for state constrained control systems is presented. First a linear controller is designed for an open-loop stable plant to show a desirable nominal performance by ignoring state constraints. And then an additional dynamic compensator is introduced to preserve the nominal performance as closely as possible int he face of state constraints. This paper focuses on the second step under the assumption that a linear controller has already been designed appropriately by using an effective controller design method. By minimizing a reasonable performance index the dynamic compensator is derived explicitly which is expressed int he plant and controller parameters. the proposed method not only guarantees the total stability of the overall resulting systems but also provides desirable output performance because it solves the state-positioning problem completely.