• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권5호
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• pp.258-264
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• 2006

This paper presents an integrative control scheme for series-type active power filters combined with shunt passive filters not only to compensate for the source voltage unbalance and current harmonics but also to correct the power factor. To reduce the power capacity of the active filters, passive filters are connected in parallel. Diode rectifiers are replaced by the PWM converters in order to feed the real power back to the source. Power factor control is performed by changing the phase of the load voltage so that the phase of the source current coincides with that of the source voltage. The resultant voltage reference is the addition of the voltage component compensating for the source voltage unbalance and harmonic currents and the voltage component correcting the power factor. The validity of the proposed algorithm has been verified by experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.139-141
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• 1993

A new scheme to measure the rotor time constant and to set the slip gain of a vector-controller is presented. The approach utilizes the phase difference between the torque producing component of the stator current and rotor current in the stationary frame. It is shown that the rotor time constant can be uniquely identified by detecting the corresponding phase difference. The simulation was carried out by considering the variation of other parameters and the torque producing component of the stator current frequency.

• 한국환경보건학회지
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• 제14권1호
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• pp.47-53
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• 1988

This study was performed to investigate a seasonal and vertical variation of the nutrients, water temperature, pH, DO, BOD, COD in Sukchon lake from May 1985 to Jan. 1986. The results were as follows. 1. Vertical descent of water temperature was the remarkable situation on Jul. and difference between surface layer and bottom layer was 3.5$\circ$C. 2. The value of pH was average 8.0 in both lake. The value of pH in the winter was average 7.6, and Summer was average 8.3. 3. The contents of dissolved oxygen was the highest value (13.0mg/l in surface layer on Jan. and the lowest value (8.1mg/l in bottom layer on Ul. 4. The contents of PO$_4$-P, NH$_3$-N, NO$_3$-N and T-N were 0.03~O.17mg/l 0.12~0.34mg/l 0.36~0.91mg/l and 0.76~1.37mg/l respectively.

• 대한기계학회논문집B
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• 제21권11호
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• pp.1458-1465
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• 1997

This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging spray.

• 한국어류학회지
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• 제18권2호
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• pp.148-150
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• 2006

1997년 10월 경상북도 울릉군 독도연안에서 한국미기록 어종인 동갈돔과 (Apogonidae)의 Apogon cookii 2개체를 채집하였다. 이 종은 줄동갈돔 (A. endekataenia)과 유사하나 체측의 암갈색 세로띠의 수가 5개이며 꼬리지느러미 기부에 눈의 동공크기의 둥근 흑색반점이 있는 점으로 구별된다. 이 종의 신한국명은 "다섯줄얼게비늘"이라 명명하였다.

• 한국어류학회지
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• 제23권4호
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• pp.305-309
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• 2011

충청남도 태안연안 암반조간대에서 채집된 3개체(체장 30.0~33.8 mm)를 근거로 둑중개과 한국미기록종인 Icelinus japonicus를 기재 보고한다. 본 종은 등지느러미 하방에 2열의 즐린이 있고, 배지느러미가 1극조 2연조로 이루어져 있으며 서골과 구개골에 이빨이 있는 특징이 있다. 신한국명으로 '두줄비늘횟대'를 제안한다.

• Animal Systematics, Evolution and Diversity
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• 제28권4호
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• pp.304-307
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• 2012

A three specimen of Icelus toyamensis, belonging to Cottidae, Scorpaeniformes, was firstly collected from the East Sea, Korea during 2007-2009. We herein described the species as the first record from Korea on the basis of these specimens. Icelus toyamensis is characterized by the following morphological combinations: spinous scales absent on the base of dorsal fin; small ctenoid scales scattered on body sides; gill rakers are short, tubular, and relatively broad; the uppermost preopercular spine is sharp and simple; dorsal fin rays VIII-IX, 20-21; anal fin soft rays 18-19; pectoral fin rays 18, and vertebrae 40-41. New Korean name of I. toyamensis is proposed as "Min-jul-ga-si-hoet-dae."

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.103-105
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• 2004

In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics and power factor simultaneously in unified active power filter systems combined with shunt passive filters is proposed, where no low/high-pass filter are used in deriving the reference voltage for compensation. Using digital all-pass filters, the phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage. The amplitude of d-axis current in a series filter is controlled as zero for power factor correction. The validity of the proposed control scheme has been verified by experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.106-108
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• 2004

서보 시스템의 전체 제어 성능은 기계적 상수의 변화와 부하 토크의 영향을 크게 받는다. 그러므로 서보 시스템의 성능을 향상시키기 위해서는 기계적 상수와 부하 토크를 정확히 알 필요가 있다. 본 논문에서는 Support Vector Regression (SVR)을 이용한 기계적 상수와 부하 토크의 추정 알고리즘을 제안한다. 여기서 제안된 추정 알고리즘인 SVR은 통계적인 학습 이론을 기반으로 한 새로운 추정 알고리즘으로 적은 샘플, 비선형, 국부해의 문제를 극복하고 강력한 성능을 발휘한다. 실험 결과는 제안된 SVR 알고리즘이 기계적 상수와 부하토크를 비교적 정확하게 추정하고 있음을 보여준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.147-149
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• 2004

This paper presents a new velocity estimation strategy of a non-salient permanent magnet synchronous motor(PMSM) drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system which has the information of rotor position error. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error to zero. For zero and low speed operation, the PI gains of rotor position tracking controller have a variable structure. The PI tuning formulas are derived by analyzing this control system using the frequency domain specifications such as phase margin and bandwidth assignment.