• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.1
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• pp.38-42
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• 2017

The wear of the third track power collector is one of the essential check factors for safe train operation. Rapid wear of the current collector accelerates the line of the catenary. In addition, the arc generated when the catenary line is turned off causes a malfunction in the minute portion of the catenary line, thereby shortening the life of the catenary line. In this paper, to analyze the mechanical wear of the current collector during driving according to the environmental factor of the Maglev(magnetic levitation train), it was divided into dry season and wet season. the wear of metallized collector, copper alloy collector and carbon collector were measured and compared with each other. The wear rate was measured according to the position of the wire, the position of the power collector and the position per hour. Microscopic photographs of the cross section and surface of the power collector were measured. The electrical currents of the metallized collector, copper alloy collector and carbon collector were measured.

• Journal of Environmental Science International
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• v.29 no.9
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• pp.907-914
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• 2020

In this study, the two-stage electroflotation-rising process was investigated with the aim of improving the performance of the conventional one-stage electroflotation process. A total of 32 min (the electroflotation and rising times were 30 min and 2 min, respectively,) was required when a current of 0.35 A was applied in the one-stage electroflotation-rising experiment. The amount of electric power required to treat 1 ㎥ of water was 1.75 kWh/㎥. For the two- stage system, the time required to achieve a turbidity removal rate of over 95% was 16 min (50% of the one-stage system). The amount of electric power required to treat 1 ㎥ of water was 0.59 kWh/㎥, which was only 33.7% of that required for the one-stage process. The total treatment time and electric power were excellent in case of the two-stage system in comparison with those of the one-stage process. The rate of turbidity removal for the horizontal electrode arrangement is 9.3% higher than that of vertical electrode arrangement. When Na₂SO₄ was used as the electrolyte, the optimum electrolyte concentration was 1.0 g/L.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.189-191
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• 1994

YBCO bulks for levitation have fabricated using MPMG method. The superconducting properties and repulsive/attractive force against permanent magnet were investigated for the specimens annealed at various periods after MPMG. A linear induction motor type levitation - traveling vehicle using the pinning force of MPMG processed YBCO bulk has fabricated. The floating or hanging small vehicle mounted with two YBCO pellets was confirmed to travel stabley on the Nd-Fe-B permanent magnet track. The traveling speed of the vehicle was confirmed to depend on AC frequency linearly. At 200 Hz, the travel ins speed was found to be 110 cm/sec.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.902-910
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• 2016

This paper presents the overall measurement system for on-line test of super-speed maglev train. The super-speed maglev train is composed of vehicle, propulsion, power, and so on. In order to evaluate and diagnose for sub-system, we made overall measurement system. Just like the other measurement system, it is designed to distributed type. The hardware is consist of SCXI, PXI, Terminal, UPS, and so forth. It is installed on a train, control room, power room and track to collect lots of signals. The software controls hardware system, monitors main data such as inverter current, converter voltage. Using the measurement system, we evaluated a lot of performances for vehicle, track, and so forth. Through the developed system have improved reliability and safety for super-speed maglev train.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.209-210
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• 2007

본 연구에서는 건설현장에서 빈번히 발생하는 안전사고를 줄이기 위해 근로자의 안전모 턱끈 착용을 도와주고 안전관리 감독자가 쉽게 확인 및 관리할 수 있는 전자식 안전모 착용 확인 시스템을 개발하였다. 안전모 착용을 확인하기 위해 마그네틱 근접 센서를 안전모 턱끈에 장착하여 안전모 착용 여부를 검출할 수 있게 하였다. 그리고 무선 센서 네트워크를 구성하기 위해 424.700MHz 주파수를 사용하는 무선 모듈을 개발하여 안전모의형에 장착하여 센서 노드(Sensor Node)를 구성하였으며, 메쉬 토폴로지(Mesh Topology)를 적용하였다. 그리고 중앙 관리실에서 근로자의 상황 인지를 위한 안전모 확인 모니터링 시스템을 개발하였다. 본 시스템으로 인하여 근로자의 안전을 도모하고, 안전 사고에서 근로자의 부상 및 인명 손실을 최소화할 수 있으며, 건설용 엘리베이터 안전 상황 인지, 타워크레인 안전 문제등의 시스템으로 활용이 가능할 것이다.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.221-225
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• 2005

This paper proposes a gain scheduled control technique using time-delay for the nonlinear system with plant uncertainties and unexpected disturbances. The time delay-based gain scheduled control depends on a direct estimation of a function representing the effect of uncertainties. The information from the estimation is used to cancel the unknown dynamics and the unexpected disturbances simultaneously. The proposed estimation scheme with a finite convergence time is formulated in order to estimate the unborn scheduling variable variation. In other words, the time delay-based gain scheduled control uses the past observation of the system's response and the control input to directly modify the control actions rather than to adjust the controller gains or to identify system parameters. It has a simple structure so as to minimize the computational burden. The benefits of this proposed scheme are demonstrated in the simulation of an electromagnetic suspension system with plant uncertainties and external disturbances, and the proposed controller is compared with the conventional state feedback controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1782-1791
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• 2017

In this paper, an optimal design of hybrid magnetic levitation(Maglev) system using intelligent optimization algorithms is proposed. The proposed maglev system adopts hybrid suspension system with permanent-magnet(PM) and electro magnet(EM) to reduce the suspension power loss and the teaching-learning based optimization(TLBO) that can overcome the drawbacks of conventional intelligent optimization algorithm is used. To obtain the mathematical model of hybrid suspension system, the magnetic equivalent circuit including leakage fluxes are used. Also, design restrictions such as cross section areas of PM and EM, the maximum length of PM, magnetic force are considered to choose the optimal parameters by intelligent optimization algorithm. To meet desired suspension power and lower power loss, the multi object function is proposed. To verify the proposed object function and intelligent optimization algorithms, we analyze the performance using the mean value and standard error of 10 simulation results. The simulation results show that the proposed method is more effective than conventional optimization methods.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.162-165
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• 2004

현재 한전은 전력자동화시스템에 다양한 통신매체를 사용하지만 경제적, 기술적, 지역적, 운용 및 유지보수 측면에서 문제점을 내포하고 있어 다양한 통신망을 적용하여 자동화시스템을 사용 중에 있다. 산악지역이나 오지는 대부분이 유 무선통신 취약 지역이므로 이에 대한 감시 제어망 구축이 힘든 형편이다. 이러한 여건 속에 국내 위성사업의 기술력 확보, 이용료 하락 및 활성화로 위성통신이 경쟁력 있는 통신망으로 부상되고 있다. 하지만 현재의 위성통신서비스는 방송서비스 및 음성서비스가 대부분이며, 위성통신을 이용한 데이터서비스는 일부회사에 국한하여 사용 중에 있다. 또 전력산업구조개편에 따라 분사된 발전소 와 전국에 산재한 배전사업소의 광역 네트워킹에 대한 필요성도 증대되고 있는 시점이다. 본 연구에서는 산재되고 분산되어 있어 감시제어가 힘든 기기에 대한 통신망 해결책을 제시한다. 또한 전력서비스에 적용하기 위한 위성통신망을 구축하고 전력산업 관리의 효율성을 극대 화하기 위한 적용방안을 제시하고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.321-324
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• 2024

본 논문에서는 LLM(Large Language Models) 기반의 STT 결합 챗봇 시스템을 제안한다. 제조업 공장에서 안전 교육의 부족과 외국인 근로자의 증가는 안전을 중시하는 작업 환경에서 새로운 도전과제로 부상하고 있다. 이에 본 연구는 언어 모델과 음성 인식(Speech-to-Text, STT) 기술을 활용한 혁신적인 챗봇 시스템을 통해 이러한 문제를 해결하고자 한다. 제안된 시스템은 작업자들이 장비 사용 매뉴얼 및 안전 지침을 쉽게 접근하도록 지원하며, 비상 상황에서 신속하고 정확한 대응을 가능하게 한다. 연구 과정에서 LLM은 작업자의 의도를 파악하고, STT 기술은 음성 명령을 효과적으로 처리한다. 실험 결과, 이 시스템은 작업자의 업무 효율성을 증대시키고 언어 장벽을 해소하는데 효과적임이 확인되었다. 본 연구는 제조업 현장에서 작업자의 안전과 업무 효율성 향상에 기여할 것으로 기대된다.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.83-88
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• 2004

High voltage AC electric field has been applied to turbulent propane jets to investigate the effect of electric field on liftoff characteristics. Liftoff velocity and liftoff height have been measured by varying the applied voltage and frequency. Liftoff velocities were delayed and liftoff heights were reduced by applying AC, not by DC. The electric effect became disappeared with further increasing jet velocities, which shows that the effect can be explained by the balance between inertia force and electric force. The flame stabilization effect was intensified as either applied voltage or frequency increased. Plasma streamers were generated between the flame and the jet under high voltage conditions. Liftoff velocity in the absence of plasma can be well correlated by the function of voltage and frequency.