• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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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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• v.8 no.6
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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.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.6
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• pp.102-111
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• 2009

In this paper, we propose a de-interlacing algorithm that combines a motion compensation (MC) method and the vertical-temporal filter with motion compensation (MC V-T filter) according to motion compensation reliability. The MC method represent one of the best ways of improving the resolution of de-interlaced frames, but it may introduce motion compensation artifacts in regions with incorrect motion information. In these regions, the MC V-T filter that is very robust to motion vector errors can be used to correct motion compensation artifacts. The combination between two methods is controlled by the motion compensation reliability that is measured by analyzing the estimated motion vectors and the results of MC. The motion compensation reliability contains information about motion compensation artifacts of MC results and determines the combination weight according to this information. Therefore, the combination rule of the proposed method is more accurate than those of the conventional methods and it enables the proposed method to provide high quality video sequences without producing any visible artifacts. Experimental results with various test sequences show that the proposed algorithm outperforms conventional algorithms in terms of both visual and numerical criteria.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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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.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.477-484
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• 1997

In this paper, we proposed the compensation method to evaluate arousal level in different initial arousal states. Arousal level was measured by the relationship between IRI and Nz. Since Nz is affected by BI which is directly proportional to initial arousal state of subjects, the arousal level is underestimated To overcome this problem, we proposed the compensation method using modified Karolinska sleepiness scale, and determined compensation coefficients derived from this scale with five arousal levels. Applying these coefficients to portable arousal monitoring system, the proposed method in this paper could be useful for real-time evaluation and control of arousal level. As a result the developed system can detect and control the arousal state from initial drowsing sate.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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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.

• MALSORI
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• no.52
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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.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.11
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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.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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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%.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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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.