• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.127.6-127
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• 2001

In this paper, we deal with two bias compensation algorithms of acceleration sensor for measuring the galloping on power transmission line. Firstly, the block diagram of galloping measurement system is given and a galloping model is presented. Secondly, two compensation algorithms, a simple compensation and a period compensation, are proposed. A simple compensation algorithm use the drafts of velocity and distance at fixed periods, so it is useful for constant bias case. Next, a period compensation algorithm can compensate a periodic bias. This algorithm use the previous measured data and compensated data for constant period, where the period is obtained by FFT method. Lastly, the effectiveness of proposed algorithms is verified by comparing between two algorithms in simulation, and its characteristics and the bias error bound are shown, respectively.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1380-1388
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• 2013

The conventional graphical representation of the instantaneous compensation power flow for single-phase active power filters(APFs) simply represents the active power flow and the reactive power flow which flowing between the power source and the active filter / the load. But, this method does not provide the information about the rectification mode and the compensation mode of APFs, especially, the loss for each mode was not considered at all. This is very important to understand the compensation operation characteristics of APFs. Therefore, this paper proposes the graphical representation of the instantaneous compensation power flow for single-phase APFs considering the instantaneous rectification mode and the instantaneous inversion mode. Three cases are verified in this paper - without compensation, with compensation of the active power 'p' and the fundamental reactive power 'q', and with compensation of only the distorted power 'h'. To ensure the validity of the proposed approach, PSIM simulation is achieved. As a result, we could confirm that the proposed approach was easy to explain the instantaneous compensation power flow considering the instantaneous rectification mode and the instantaneous inversion mode of APFs, also, Total Harmonic Distortion(THD)/Power Factor (P.F) and Fast Fourier Transform(FFT) analysis were compared for each case.

• 대한전자공학회논문지SP
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• 제46권6호
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• pp.102-111
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• 2009

본 논문에서는 움직임 보상 결과의 신뢰도를 바탕으로 움직임 보상 순차주사화 알고리즘의 결과와 움직임 보상 수직-시간 필터의 결과를 결합하는 순차주사화 알고리즘을 제안한다. 움직임 보상 순차주사화 알고리즘은 높은 공간 해상도를 가진 고화질 영상을 생성하지만 움직임 벡터가 잘못 추정되었을 경우 눈에 띄는 에러를 발생시킨다. 반면에 움직임 보상 수직-시간 필터는 높은 공간 해상도를 제공하지는 못하지만 움직임 벡터의 에러에 강건한 특성을 가지고 있기 때문에 전체적으로 자연스러운 영상을 제공한다. 제안하는 순차주사화 알고리즘은 추정된 움직임 벡터와 움직임 보상 순차주사화 알고리즘의 결과를 분석하여 움직임 보상의 신뢰도를 추정한 후, 움직임 보상 신뢰도에 기반 한 가중치를 바탕으로 두 가지 방법의 장점을 결합한다. 제안된 방법은 움직임 보상의 신뢰도가 높은 영역에서는 높은 공간 해상도를 제공하는 움직임 보상 순차주사화 알고리즘을 적용하고 움직임 보상의 신뢰도가 낮은 영역에 대해서는 움직임 보상 수직-시간 필터를 적용하여 눈에 띄는 에러 없이 높은 공간 해상도를 가지는 영상을 생성한다. 실험 결과에서는 제안된 알고리즘이 기존의 알고리즘에 비해 시각적 및 수치적인 면에서 뛰어난 결과를 보임을 확인할 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.800-803
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• 2004

The refractive index of the laser interferometer is compensated using the simultaneously measured variations of room temperature and humidity in the method. In order to investigate the limit of compensation, the stationary test against two fixed reflectors mounted on the zerodur plate is performed firstly. From the experiment, it is confirmed that the measuring error of the laser interferometer can be improved from 0.12$\mu$m to 0.17$\mu$m by the application of the method. Secondly, for the verification of the compensating effect, it is applied to estimate the positioning accuracy of an ultra precision aerostatic stage. Two times of the refractive index compensation are performed to acquire the positioning error of the stage from the initially measured data, that is, to the initially measured positioning error and to the measured positioning error profile after the NC compensation. Although the positioning error of anaerostatic stage cannot be clarified perfectly, it is known that by the compensation method, the measuring error by the laser interferometer can be improved to within 0.15$\mu$m. English here.

• 대한의용생체공학회:의공학회지
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• 제18권4호
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• pp.477-484
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• 1997

본 논문에서는 각성도 평가시 초기 각성상태 차이에 따른 보상방법을 제안하고 보상상수를 결정하였다. 각성도는 IRI와 Nz에 의하여 측정되었다. BI는 초기 저각성상태의 영향을 많이 받게 되며 이는 각성도의 지표인 Nz 값에 영향을 주게 되어 각성수준이 실제보다 높게 평가된다. 따라서 본 연구에서는 BI의 과대평가로 인한 오판정 문제를 해결하기 위하여 수정된KSS 측도(mKSS)를 이용한 보상법을 제안하고 각성수준에 따른 수정된 KSS 측도에 대응하는 보상상수를 결정하였다. 이 보상상수를 개발된 휴대형 각성도 측정 시스템에 적용하여, 실시간으로 각성도를 평가 및 제어한 결과, 본 연구에서 제안한 보상법 및 보상상수의 유용성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.834-844
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• 2012

Nonlinear electronic loads draw harmonic currents from the power grids that can cause energy loss, miss-operation of power equipment, and other serious problems in the power grids. This paper proposes a harmonic compensation method using multiple distributed resources (DRs) such as small distributed generators (DGs) and battery energy storage systems (BESSs) that are integrated to the power grids through power inverters. For harmonic compensation, DRs should inject additional apparent power to the grids so that certain DRs, especially operated in proximity to their rated power, may possibly reach their maximum current limits. Therefore, intelligent coordination methods of multiple DRs are required for efficient harmonic current compensation considering the power margins of DRs, energy cost, and the battery state-of-charge. The proposed method is based on fuzzy multi-objective optimization so that DRs can cooperate with other DRs to eliminate harmonic currents with optimizing mutually conflicting multi-objectives.

• 대한음성학회지:말소리
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• 제52호
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• pp.145-160
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• 2004

In this paper, a new noise compensation method based on the eigenvoice framework in feature space is proposed to reduce the mismatch between training and testing environments. The difference between clean and noisy environments is represented by the linear combination of K eigenvectors that represent the variation among environments. In the proposed method, the performance improvement of speech recognition systems is largely affected by how to construct the noisy models and the bias vector set. In this paper, two methods, the one based on MAP adaptation method and the other using stereo DB, are proposed to construct the noisy models. In experiments using Aurora 2 DB, we obtained 44.86% relative improvement with eigen-environment method in comparison with baseline system. Especially, in clean condition training mode, our proposed method yielded 66.74% relative improvement, which is better performance than several methods previously proposed in Aurora project.

• 제어로봇시스템학회논문지
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• 제6권11호
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• pp.1039-1044
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• 2000

In this paper, the error caused by the measurement delay in INS/GPS integrated systems with Kalman filtering is defined and analyzed through the analytical method and the simulation. It is proved that the error of measurement delay causes not only the position error but also the estimate error of the x-axis accelerometer bias when a vehicle turns. And the estimation method of the delay time and the compensation method using an extrapolation method are presented. The performance of the compensation method is shown by the analytic method and the simulation.

• 전자공학회논문지D
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• 제35D권5호
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• pp.63-68
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• 1998

The absolute pressure sensor using SDB wafer has been fabricated. the structure of the sensor consists of two wheatstone bridges and a diaphragm. One of the two wheatstone bridges is located on the edge of diaphragm, and the other is located on the center of diaphragm. The diaphragm cavity is sealted in vacuum (~10$^{5}$ Torr) to reduce the effect of temperature due to the vapor in the cavity on the sensitivity of pressure sensor. This is the minor method of temperature compensation method. In this experiment the main compensation method is to use the difference of the two bridge offset voltages. The drift of offset voltage with temperature is reduced by using this method so that temperature charcteristics is improved. In this method the temperature effect in the range of 22~100.deg. C was compensated over 80%.

• 전력전자학회논문지
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• 제23권2호
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• pp.121-128
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• 2018

This work proposes a simple control method of a buck-type active power decoupling circuit that can minimize the ripple values in the dc link voltage. The proposed method utilizes a simplified duty calculation method and an optimal compensation gain tracking algorithm with variable-step approach. Thus, the dc link voltage ripple can be effectively reduced through the proposed method along with rapid response in tracking the optimum compensation gain. Moreover, the proposed method has better dynamic responses in the load fluctuation or abnormal situation. MATLAB/Simulink simulation and hardware-in-the-loop-simulation(HILS)-based experimental results are presented to validate the effectiveness of the proposed control method.