• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.469-470
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• 2017

디지털 계측기는 전압 또는 전류 한주기에 대하여 여러 번 샘플링 하여 실효치를 구하고 위상은 전압영점에서 카운터를 시작하여 전류 영점에서 그 카운터의 값에 의해 전력을 구하는 것이 일반적이다. 그러나 계측대상 주파수가 샘플링 주파수와 유사한 경우 사실상 전력 계측이 불가능하게 되는 취약점을 안고 있다. 따라서 본 논문에서는 계측대상 주파수가 샘플링 주파수와 유사한 경우 샘플링 시프트 기능을 사용하여 계측하는 정규화 기법과 이를 이용하여 DFT를 사용하여 각 차수의 고조파 성분을 분석할 수 있는 알고리즘을 제안한다. 또한 제안된 방식을 Psim을 이용한 시뮬레이션을 통하여 그 타당성을 검증하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1283-1289
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• 2016

Electrical energy is the essential resource for modern society. Recently, the demand for power was significantly increased. Increase of power demand has lead to a decrease in the power quality. Power quality in modern society has been an important factor that can cause a major problem throughout the home and general industry. Therefore, we need a system for preventing the power quality problems. To avoid power issues, it is important that the measurement of the power quality and initial response. In this paper, we propose real-time power quality measurement system and harmonics monitoring system. We design the system using DM240001 board include dsPIC33FJ256GP710A of microchip. This system can adapt three-phase three-wire system. And optimized the algorithm, we can measure momentary changes of the power system. In addition, designed system can measure harmonics distortion like to VTHD, ITHD and ITDD for 31th harmonics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.508-517
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• 2009

The real time movement of the caisson was measured when it was open to the waves during breakwater construction. As a result of measurement, no more settlement after the preloading in condition of designed loading was expected but sudden abnormal settlement took place through whole area of the breakwater when waves occurred by typhoon effect. To clarify the reason of this case, wave of the site has been reproduced and the equivalent wave pressure on the caisson was calculated. The numerical analysis of the effect of wave to the ground had been done. Site measurement data is in accordance with the result of numerical analysis.

• NEWSLETTER 전기공업
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• no.97-19 s.188
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• pp.32-43
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• 1997

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.49-63
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• 1989

Wave drift forces which are small in magnitudes compared to the first order wave exciting forces can cause very large motion of a vessel in waves. In this paper a theoretical and experimental analysis is made of the mean and slowly varying wave dirft forces on the semi-submersible platform. Theoretical calculations are performed by using near field method with three dimensional diffraction theory and model tests are carried out in regular and irregular waves with a 1/60 semi model. Test results are compared with theoretical calculations and the mooring spring effects in the test are discussed.

• Journal of KSNVE
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• v.8 no.6
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• pp.1158-1165
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• 1998

Low frequency interior noise in cars is mainly due to structure-borne excitations which are related with road excitation and component vibrations such as suspension and engine mounts. In order to analyze the annoying interior noise. a technique (Transfer Path Analysis) is introduced to find a noise source and the path of that noise. In this study, TPA is reviewed theoretically and applied to investigate the case when the low frequency interior noise at front seat due to road excitations needs to be optimized. The subjective and objective appraisal was performed under the conditions that a testing vehicle traveled on asphalt at 30 km/h. so that the low frequency to be eliminated was detected. The related vibration and noise data for TPA were measured on running and static vehicle. The results reveal that the noise contribution along the z-direction of trailing arm is prominent to low frequency interior noise.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.163-171
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• 2020

A model test for assessment of towing stability and seakeeping of a multi-purpose mobile base (MMB) was performed in calm water and wave conditions. Scale ratio of the MMB was 1/48. Tension of the towing line was measured during tests to estimate effective power to tow the full scale MMB. The tests were repeated with towing speed. In addition, an inertial measurement unit was used to measure six DOF motion of the model. Seakeeping performance was assessed through the captive model test.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.249-258
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• 2000

본 논문에서는 지반-구조물 상호작용계의 강성에 관련된 물성값들을 지진계측결과를 바탕으로 효과적으로 추정할 수 있는 방법에 대해 연구하였으며 제안된 방법의 검증은 국제공동 연구의 일환으로 최근 대만의 화련에 건설된 대형지진시험구조물에서 계측된 지진 응답을 사용하여 수행하였다. 지반-구조물 상호작용계의 지진응답해석을 위해서 구조물과 근역지반은 축대칭유한요소로 모형화하고 원역지반은 축대칭 무한요소를 사용하였으며 이때 입력 지진하중은 부구조법에 근거한 파입력기법이 고려되었다 지진계측결과를 사용하여 각 영역의 물성값을 제약적 최속강하법을 사용하여 추정하였는데 추정된 계수들을 사용하여 계산된 지진응답이 계측치와 매우 잘 일치하여 추정결과의 타당성을 검증할 수 있었다.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.3
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• pp.125-130
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• 1992

A digital 6-dof motion measuring system is developed using 7 accelerometers following Miles'[1] method. A snoic wave height gauge is also developed to measure the relative wave height at the foremost end of the ship. By combining the time series of both 6-dof motions and relative wave height, we can estimate the time series of real sea wave. Results of model tests shows the validity of the developed system.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2106-2108
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• 2003

단상 또는 3상의 AC 전원의 전류나 전압 또는 전력을 계측하기 위해 Analog Signal들을 Digital Signal로 변환하여 특정 Algorithm의 연산을 수행하여 결과를 얻는 과정을 Microprocessor를 이용하여 처리하는 방법은 산업현장이나 연구개발에서 흔히 사용하는 방법이다. 본 논문에서는 Microprocessor를 이용하여 보편화된 3가지의 계측 Algorithm인 DFT, True RMS, Summation Algorithm을 사용하여 동일 System에 3상 AC의 전류 부하를 일정 범위에서 가변 하여 인가시키면서 계측 값을 사용하여 Algorithm의 계측 결과의 오차율과 연산에 소요되는 시간과 외부 잡음인 Surge, Impulse, 정전기, 방파, 고조파에 대한 System의 처리 효율을 연구 하였다.