• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.303-308
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• 2016

A light-emitting diode (LED) has been increasingly applied to various industrial fields and general lightings because of its high efficiency, low power consumption, environment-friendly characteristic and long lifetime. To drive this LED lighting, various types of power converters have been applied. Also, power factor correction (PFC) techniques play an important role in the power supply technology. In this paper, design and control of a DCM interleaved boost PFC converter is discussed. The proposed converter can reduce current ripples at input and output side by cancelling an each phase of inductor currents. Since the IC does not require the auxiliary winding of inductor for current detection, simple PFC circuit is achieved. Therefore, it contributes to increase efficiency and downsize the whole system volume, cost. Also, the performance of the proposed system is demonstrated through experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.303-310
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• 2004

In this paper, for compensating dynamic voltage sag and harmonic current, 3-phase hybrid series active power filter based on the space vector detection is proposed. The Space vector algorithm for detecting the voltage sag and the harmonic current in compared with conventional theory is a simple method for calculating the compensating reference without any coordinated transformation. The effectiveness of the proposed system is verified by the PSIM simulation in the steady state and the transient state, which the proposed system is able to simultaneously compensate harmonics and source voltage unbalance / sag.

• Journal of Biomedical Engineering Research
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• v.30 no.5
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• pp.412-417
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• 2009

The purpose of this study was to assess the ability of this device during clinically important episodes of extravasation. The extravasation detection accessory (EDA) system was based of infrared ray with detection sensor, an amplifier, alarm device, receiver, cable and a computer based system. This study was a prospective, observational study in which the EDA system was used to monitor the automated mechanical injection of contrast media. Three hundred patients referred for contrast media enhanced body computed tomography studied in a prospective, observation study in which the EDA system was used to identify and interrupt any injection associated with clinically important extravasation. There were 8 true-positive cases, 276 true-negative cases, 15 false-positive cases and 1 false-negative cases. The EDA system had a sensitivity of 88.8% and a specificity of 94.8% for the detection of clinically important extravasation. The EDA system had good sensitivity for the detection of clinically important extravasation and the EDA system has the clinical potential for the early detection of extravasation of the contrast medium that is administered with power injectors.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.248-253
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• 2006

The purpose of this study is to develop a portable gait-event detection system which is necessary for the cycle-to-cycle FES(functional electrical stimulation) control of locomotion. To make the system portable, we made following modifications in the gait signal measurement system. That is, 1) to make the system wireless using Bluetooth communication, 2) to make the system small-sized and battery-powered by using low power consumption ${\mu}$ P(ATmega8535L). The gait-events were analyzed in off-line at the main computer using ANN(Artificial Neural Network). The Proposed system showed no mis-detection of the gait-events of normal subject and hemiplegia subjects. The performance of the system was better than the previous wired-system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.1
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• pp.35-40
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• 2012

An AC generator is an important component in producing an electric power and so it requires highly reliable protection relays to minimize the possibility of demage occurring under fault conditions. It is a need for research of digital generator protection system(DGPS) for the next-generation ECMS and an efficient operation of protection control system in power station. However, most of protection and control system used in power plants have been still imported as turn-key and operated in domestic. This may cause the lack of the correct understanding on the protection systems and methods, and thus have difficulties in optimal operation. In this paper, presented ratio differential relaying(RDR) is main protective element in generator protection IED. The fault detection technique, operation zone and setting value of the RDR were studied and, compared with two of the fault detection algorithm. For evaluation performance of the RDR, the data obtained from ATPDraw5.7p4 modeling was used. The proposed methods are shown to be able to rapidly identify internal fault and did not operate a miss-operation for all the external fault.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.9
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• pp.450-455
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• 2001

We proposed a new sensitivity verification method for the UHF partial discharge(PD) detection system. Initially, we measure the UHF power induced by 5 pC PD which takes place near UHF sensor. Subsequently, we inject the swept UHF signal from a network analyzer into the GIS and measure the attenuation of the signal along the 71S Both the UHF power by 5 pC PD and the attenuation make it possible to verify the sensitivity and spatial coverage of the PD detection system. This method doesn\`t require the calibration of injected pulse type UHF signal into the GIS and makes us precisely measure the attenuation in frequency domain.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.185-186
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• 2007

In this paper, We propose the selective detection scheme based on pulse repetition considering Bit Error Rate (BER) performance and complexity of noncoherent Ultra Wide Band (UWB) systems. To consider system complexity, the proposed scheme transmits the UWB signals by pulse repetition at the transmitter, like the conventional Pulse Repetition Coding (PRC). However, to effectively improve BER performance of the system the proposed scheme performs selective detection by estimating the Signal-to-Noise Ratio (SNR) of the received pulse-repeated signal at the receiver. Hence, the proposed scheme effectively improves BER performance of the noncoherent UWB systems without increase of the system complexity, as compared to the conventional PRC algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1774-1779
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• 2016

This paper proposes a portable cable fault detection system with automatic fault distinction and distance measurement using time-frequency correlation and reference signal elimination method and automatic fault classification algorithm in order to have more accurate fault determination and location detection than conventional time domain refelectometry (TDR) system despite increased signal attenuation due to the long distance to cable fault location. The performance of the developed system method was validated via an experiment in the test field constructed for the standardized performance test of power cable fault location equipments. The performance evaluation showed that accuracy of the developed system is less than 1.34%. Also, an error of automatic fault type and location by detection of phase and peak value through elimination of the reference signal and normalization of correlation coefficient and automatic fault classification algorithm not occurred.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.2
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• pp.101-111
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• 2023

Many spoofing detection studies have been conducted to cope with the most difficult types of deception among various disturbances of GPS, such as jamming, spoofing, and meaconing. In this paper, we propose a spoofing detection scheme based on elevation masked-relative received power between GPS L1 and L2 signals in a system using a multi-band array antenna. The proposed scheme focuses on enabling spoofing to be normally detected and minimizes the possibility of false detection in an environment where false alarms may occur due to pattern distortion among elements of an array antenna. The pattern distortion weakens the GPS signal strength at low elevation. It becomes confusing to detect a spoofing signal based on the relative power difference between GPS L1 and L2, especially when GPS L2 has weak signal strength. We propose design parameters for the relative power threshold including beamforming gain, the minimum received power difference between L1 and L2, and the patch antenna gain difference between L1 and L2. In addition, in order to eliminate the weak signal strength of GPS L2 in the spoofing detection process, we propose a rotation matrix that sets the elevation mask based on platform coordinates. Array antennas generally do not have high usefulness in commercial areas where receivers are operated alone, but are considered essential in military areas where GPS receivers are used together with signal processing for beamforming in the direction of GPS satellites. Through laboratory and live sky tests using the device under test, the proposed scheme with an elevation mask detects spoofing signals well and reduces the probability of false detection relative to that without the elevation mask.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.351-352
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• 2016

Since anti-islanding scheme of grid-connected inverter is a key function of standards compliance, unintentional islanding results in safety hazards, reliability, and many other issues. Therefore, many anti-islanding schemes have been researched, however, existing anti-islanding schemes show poor power quality and non-detection zone issues. Besides, most of them have problems which deteriorate performance of islanding detection under parallel-operation. Therefore, this paper proposes a new anti-islanding scheme that has both negligible power quality degradation, no non-detection zone and precise islanding detection under parallel-operation. Finally, both simulation and experimental results validate the proposed scheme.