• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.876-883
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• 2012

The paper investigates three types of transfer function methods for detecting displacements of winding in a model transformer. To acquire these transfer functions, the measuring method of input voltage, current and its response is used in impulse method. The applied impulse voltages had three rising times, which were short rising time (less than 0.6 ${\mu}s$), medium rising time (about 0.8 ${\mu}s$) and long rising time (about 1 ${\mu}s$) in front waves. Every 10 measurements of voltage and current waves were averaged from 50 measurements of voltage and current waves. These transfer functions were tested in normal, 24mm elevated and 48mm elevated windings conditions and were analyzed with correlation coefficients and spectrum deviations. In the analysis, the results depend on the types of transfer functions and the rising times of input voltages.

• 센서학회지
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• 제20권2호
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• pp.90-95
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• 2011

In order to protect human lives from disease, various biosensors having the potential to analyze a variety of biomolecules have been utilized. Biosensors constitute one of the most promising ways to monitor and detect various biomolecules corresponding to diseases. In this study, we demonstrate that the reaction of streptavidin molecules with biotin on a gold electrode can be detected using the twoelectrode method with a gold electrode and a platinum reference electrode. We also show the characteristics of the electrical current response. While detecting 2-${\mu}M$ streptavidin molecules dissolved in phosphate buffered saline(PBS) solution, we found that an analytical biosensor can operate on the principle of detecting an antigen-antibody reaction event of protein molecules using the two-electrode method. We think that the "potential step" method might be useful to detect the occurrence of any antigen-antibody reactions and can be combined with other devices or ICs such as BJTs, MOSFETs, and OP-amps for the detection of biomolecules of diseases.

• 조명전기설비학회논문지
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• 제29권5호
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• pp.71-79
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• 2015

Recently, new Low Voltage DC (LVDC) power distribution systems have been constantly researched as uses of DC in end-user equipment are increased. As in conventional AC distribution system, High Impedance Fault (HIF) which may cause a failure of protective relay can occur in LVDC distribution system as well. It, however, is hard to be detected since change in magnitude of current due to the fault is too small to detect the fault by the protective relay using overcurrent element. In order to solve the problem, this paper presents an algorithm for detecting HIF using accumulated energy in LVDC distribution system. Wavelet Singular Value Decomposition (WSVD) is used to extract abnormal high frequency components from fault current and accumulated energy of high frequency components is considered as the element to detect the fault. LVDC distribution system including AC/DC and DC/DC converter is modeled to verify the proposed algorithm using ElectroMagnetic Transient Program (EMTP) software. Simulation results considering various conditions show that the proposed algorithm can be utilized to effectively detect HIF.

• 한국ITS학회 논문지
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• 제15권4호
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• pp.153-160
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• 2016

영상취득 장치를 이용한 지능화된 감시 장치의 개발 기술 또한 발전하고 있다. 비교적 고속으로 움직이는 객체를 탐지해야 하는 분야에서 무엇보다 중요한 것은 배경영상 갱신에 대한 부하를 효과적으로 줄여서 실시간적으로 갱신할 수 있어야 하는데 현재 범용 컴퓨터 능력으로는 질감 등을 특징으로 추출하는 방법 등은 대부분 연산처리의 부하 때문에 적용상의 한계가 있다. 본 논문에서는 적어도 초당 30프레임의 카메라 영상에서 주행 중인 자동차와 같이 고속으로 움직이는 객체를 탐지하는 응용영역에서 실시간으로 배경 영상을 갱신하는 알고리즘을 제시하고, 실제 입력영상에서 객체 영역을 추출하는 시험을 통해 성능을 분석하였다.

• 문화기술의 융합
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• 제8권3호
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• pp.501-506
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• 2022

COVID-19의 영향으로 로드샵과 수많은 오프라인 매장은 예전과 달리 많은 어려움을 격고 있다. 이에 대응하기 위하여 뷰티업계에서는 고객들의 수요를 충족하고자 다양한 비대면 서비스들을 선보이고 있다. 본 논문에서는 비대면 서비스 중 모바일 환경에서 이미지 기반 퍼스널 컬러 측정 기술의 품질과 제품 추천 서비스에 대한 고찰을 진행하였다. 현재 글로벌 서비스 시장에서 많이 활용되고 있는 엔진에 대한 다양한 실험과 실제 측색 장비를 활용한 컬러 측정 데이터에 대한 비교 분석, 서비스 구현 및 지표 데이터 등으로 구성되었다. 정밀한 실험결과를 위해 일관된 실험 환경에서 실험을 진행하였다. 본 논문이 이미지 기반 피부 컬러 측정에 따른 개인화 제품 추천 서비스의 확장에 활용될 수 있기를 기대한다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권9호
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• pp.464-469
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• 2004

The leakage current of transmission insulators contaminated with salt, clay, and kaolin was examined in the Gochang's Long Periods Testing Center. The Insulators were artificially contaminated and estimated with the method of equivalent salt deposit density(ESDD). The artificially contaminated insulators were installed with the same condition as in the real transmission power line and applied with 154 (kV). The leakage current of the artificially contaminated insulators was measured with environment conditions, such as temperature and humidity by the a automatic leakage current detecting system. The leakage current of heavily contaminated insulator was abruptly increased above 72［%］ of humidity, even though the leakage current was similar between the contaminated and non-contaminated insulators below 72［%］ of humidity. Also, it was found that the humidity was much more important than the temperature in the leakage current of transmission insulators. The leakage current of contaminated insulator was decreased when it was plenty of rainfall, resulting from natural washing.

• 전력전자학회논문지
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• 제8권1호
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• pp.40-47
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• 2003

A low-cost current-sensing scheme for the motor drives with MOSFET is described. Many motor drives usually employ the common current sensors to measure current for the purpose of control or protection. These current sensors, however, significantly burden the power circuit with the size and cost. The proposed current-sensing scheme utilizes information concerning MOSFET's On-voltage and On-resistance. An analogue circuit detecting On-voltage can overcome the above disadvantages because the circuit is small and is made at a low cost, and the fuzzy inference for On-resistance is also simply designed based on MOSFET's characteristics. The validity of this scheme will be experimentally verified by adopting the current control of a battery car.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.231-233
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• 2006

Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, arc current control algorithm is designed for the interruption of arc fault current which is occurred in the low voltage network. This arc is one of the main causes of electric fire. General arc current sensor has troubles for detecting arc currents, thus we would like to propose the arc current detection method without current sensor. In this paper, arc discharge currents within power lines are being detected through the arc current control algorithm.

• 대한임베디드공학회논문지
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• 제12권2호
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• pp.79-88
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• 2017

One of the important applications of activity sensing in the home is energy monitoring. Many previous methodologies for detecting and recognizing household appliances have been proposed. This paper presents an approach that uses an energy metering circuit (EMC) to classify and identify the various electrical devices in home based on root-mean-square (RMS) consumed current value. EMC gathers the RMS current values created by appliance state transition (e.g., on to off) and apparatus operating process. In this paper, an identification algorithm is proposed to detect a change in current levels using the standard deviation of current signals and their average values. In addition, characteristic of the appliance is extracted concerning four feature parameters concerning the number of current levels, the minimum level, the maximum level, and signal-to-noise ratio (SNR) of them. Experiment results validate the reliable performance of the proposed identification method for 11 representative appliances.

• 전기학회논문지
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• 제57권3호
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• pp.494-500
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• 2008

This paper presents the analyzed result of the series arc fault current by using the discrete wavelet transform. The series arcing is caused by a loose connection in series with the load circuit. The series arc current is limited to a moderate value by the resistance of the device connected to the circuit, such as an appliance or a lighting system. The amount of energy in the sparks from the series arcing is less than in the case of parallel arcing but only a few amps are enough to be a fire hazard. Therefore, it is hard to detect the distinctive difference between a normal current and a intermittent arc current. This paper, presents the variation of the ratio of peak values and RMS values of the series arc fault current, and proposes the novel series arc fault detecting method by using the discrete wavelet transform. Loads such as a CFL lamp, a vacuum cleaner, a personal computer, and a television, which has the very similar normal current with the arc current, were selected to confirm the novel method.