• 전력전자학회논문지
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• 제8권6호
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• pp.569-575
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• 2003

본 논문에서는 스위칭 전원장치의 효율을 높은 정밀도로 측정하고 분석학 수 있는 PC 기반 가상계측 기를 구성하여 운용한 결과를 보고한 것이다. 고전압 저전류 방식에 적합한 간접 측정방식과 저전압 대전류 전원장치에 적합한 직접 측정방식의 비교를 수행하였으며, 직접 측정방식에서는 측정 편차를 최소화시키기 위해서 보상 기능을 추가하였다. 구성된 가상계측기의 성능을 검증하기 위해서 50W급 통신기용 전원장치를 대상으로 특성을 계측하였다. 그 결과 기존의 방법에 비해서 전원장치의 정상상태 특성을 정확하게 평가할 수 있으며, 반복 측정 오차를 줄일 수 있을 뿐만 아니라, 실시간 측정이 가능하며, 측정 시간도 절약할 수 있었다.

• 한국통신학회논문지
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• 제28권11A호
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• pp.902-911
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• 2003

에미터 면적이 2.0${\times}$20 $\mu\textrm{m}$$^2$인 단위 InGaP/GaAs HBT power cell을 이용하여 IMT-2000 단말기용 MMIC 2단 전력 증폭기를 설계 및 제작하였다. 온도 변화에 따른 전력증폭기의 RF 특성 변화를 보상시킬 수 있으며, 외부 조절 전압으로 대기전류를 줄일 수 있는 능동 바이어스 회로를 채택하였다. HBT의 실측정 S 파라미터와의 fitting을 통하여 비선형 등가 회로 파라미터를 추출하였고, load-pull 시뮬레이션으로 최대 출력 정합 임피던스를 결정하였다. 제작 및 측정 결과, MMIC 2단 전력증폭기는 on-wafer 측정에서 23 ㏈의 전력 이득과 28.4 ㏈m의 출력 전력( $P_{1-}$㏈/) 및 31%의 전력 부가 효율을 얻었으며, FR-4 기판상에 off-chip 출력정합회로를 구현한 COB 측정에서 22.3 ㏈의 전력이득과 26 ㏈m의 출력전력 및 28%의 전력부가효율을 얻었으며, -40 ㏈c의 ACPR 특성을 얻었다..

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4855-4862
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• 2015

본 논문에서는 전력설비의 동작 상태를 주기적으로 감시 및 기록함으로써 전기안전사고를 예방하고 사후 원인 분석을 지원하기 위한 저가형 전력 성분 측정 및 기록 시스템을 제안한다. 제안된 시스템에서는 정밀한 전력 성분의 측정과 기록, 원격 측정이 가능하면서도 비용을 줄일 수 있도록 부품을 선정하여 제작하였다. 특히, IEEE 1459-2010에 정의된 전력 성분을 계산하기 위해 MAXIM사의 78M6631을 이용함으로써 저비용 고성능 시스템 구현이 가능하였다. 개발된 시스템은 공인 시험기관에서 사용하고 있는 YOKOGAWA 전력분석기 WT1600 과 같은 표준 장비를 이용하여 측정 성능 시험을 실시하였다. 그 결과 측정 오차가 0.5%이하로 나타났고 6개월 이상 현장에 설치하여 동작 신뢰성과 원격 측정 성능 시험을 실시하여 그 성능을 입증하였다.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.304-312
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• 2016

Purpose: Soil strength has been measured using a cone penetrometer, which is making it difficult to obtain the spatial data required for precision agriculture. Our objectives were to evaluate real-time horizontal soil strength (RHSS) to measure soil strength in real time while moving across the field. Using the RHSS data, the tillage depth was determined, and the power consumption of a tractor and rotavators were compared. Methods: The horizontal soil-strength index (HSSI) obtained by the RHSS was compared with the cone index (CI), which was measured using a cone penetrometer. Comparison analysis in accordance with the measurement depth that increased at 5-cm interval was conducted using kriged maps at six sensing depths. For tillage control and evaluation of the power consumption, the system was installed with a potentiometer for tillage depth, a torque sensor from the rear axle, and a power take-off (PTO) shaft. Results: The HSSI was lower than the CI, but they were the same at 54.81% of the total grids for the 5-cm depth and at 3.85% for the 10-cm depth. In accordance with the recommended tillage map, tillage operations between 0 and 15 cm left 2.3% and 7% residue cover on the soil, and that between 20 and 10 cm covered a wider utilization of 3% and 18.4%, respectively. When the tillage depth was 15 cm, the comparison result of the power requirements between the PTO and rear axle in terms of control performance revealed that the maximum power requirements of the axle and PTO were 44.63 and 23.24 kW, respectively. Conclusions: An HSSI measurement system was evaluated by comparison with the conventional soil strength measurement system (CI) and applied to a tractor to compare the tillage power consumption. Further study is needed on its application to various farm works using a tractor for precision agriculture.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.37-40
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• 2001

Subject of this paper is analysis of channel noise and impedance characteristics for high speed power line communication to concerned noise of transmission line and impedance in the frequency range up to 30MHz. Parameters of transmission line was inducted from experimentally power line channel measurement. Moreover, Analysis of compared based on measurement of channel characters with simulation test for appear characters.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.116-118
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• 2004

This paper gives a measurement data of the feeder demand factor in small size apartments. The power load measurement data of the feeder shows that the feeders have $10{\sim}30[%]$ margin in capacity. But this margin is not enough to keep up with the trend of power consumption increase from long term standpoint. So it is necessary to measure the feeder power load periodically for the purpose of optimal feeder capacity estimation

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.336-339
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• 2002

CISPR(Committee Internationale Special des Perturbations Radio Electriques) has proposed limits on the noises emitting from power lines and signal lines. But different measurement environment and different measurement methods are used in different countries. This difference causes much confusion in understanding the results measured by different test laboratories. In this paper, we measure EMI noise using the absorbing clamp method that takes short measurement time and is described in CISPR 13, 14-1, 16-2. We analyze the cause of the difference of measurement results.

• 조명전기설비학회논문지
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• 제30권3호
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• pp.73-78
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• 2016

3phase induction motor consumes 40% of national electric power. so It is one of the most important electric device for the national power policy. The efficiency measurement is carried out by IEC standards. After the temperature rise test, It's difficult to measure the winding resistance immediately. because of inertia and power cut-off time. Therefore, IEC standards suggest the measurement time. But during the measurement time, the winding temperature cools down. It causes the value of winding resistance is variable. Several conditions which possibly occurred by the measurement time of IEC 60034-1 are suggested. and The efficiency evaluation of 3phase induction motors is carried out by IEC 60034-2-1 with the several conditions. As the results, we find out the winding resistance rapidly goes down within 15 sec. so It proves that the winding resistance should be measured within 15 sec. for the efficiency evaluating of 3phase induction motor.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.372-380
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• 2012

The optical method Digital Speckle Correlation Measurement (DSCM) has been extensively applied due its capability to measure the entire displacement field over a body surface. A formula of displacement measurement errors by the gradient-based DSCM method was derived. The errors were found to explicitly relate to the image grayscale errors consisting of sub-pixel interpolation algorithm errors, image noise, and subset deformation mismatch at each point of the subset. A power-law dependence of the standard deviation of displacement measurement errors on the subset size was established when the subset deformation was rigid body translation and random image noise was dominant and it was confirmed by both the numerical and experimental results. In a gradient-based algorithm the basic assumption is rigid body translation of the interrogated subsets, however, this is in contradiction to the real circumstances where strains exist. Numerical and experimental results also indicated that, subset shape function mismatch was dominant when the order of the assumed subset shape function was lower than that of the actual subset deformation field and the power-law dependence clearly broke down. The power-law relationship further leads to a simple criterion for choosing a suitable subset size, image quality, sub-pixel algorithm, and subset shape function for DSCM.

• Journal of Advanced Marine Engineering and Technology
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• 제33권8호
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• pp.1152-1161
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• 2009

신조선 선박에서 시운전 중 주 추진 시스템의 동력을 측정하는 방법은 스트레인 게이지를 이용하여 축의 변형률로부터 얻어지는 직접적인 방법과 기계적인 또는 전기적인 픽업을 이용하여 계측한 실린더연소압력으로부터 환산된 면적에 의한 간접적인 방법으로 구분할 수 있다. 이러한 동력은 장주기로 선박의 여러 가지 해상 운동에 의해서 그리고 단주기로는 축계의 비틀림, 축계 배치 및 횡진동의 영향에 의해서 변동한다. 본 논문에서는 축동력측정과 평가를 위하여 통계적인 해석법을 소개하고 있고, 저속2행정디젤엔진과 감속기를 포함 중속 4행정 디젤엔진 모델에 의해서 이들이 확인되고 있다.