• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.931-932
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• 2006

This paper proposes a control algorithm for 3-phase 4-wire series active power filter. This control algorithm compensates harmonics and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this control algorithm is direct extraction of compensation voltage references. Therefore, calculation time is shorten and the performance of series active power filter is improved. Compensation principle of the proposed control algorithm is presented in detail. Experimental results are shown to verify the effectiveness of the proposed control algorithm.

• 한국통신학회논문지
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• 제28권4C호
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• pp.384-391
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• 2003

Blind channel identification and equalization attempt to identify the communication channel and to remove the inter-symbol interference caused by a communication channel without using any known trainning sequences. In this paper, we propose a blind adaptive channel identification and equalization algorithm with phase offset compensation for single-input multiple-output (SIMO) channel. It is based on the one-step forward multichannel linear prediction error method and can be implemented by an RLS algorithm. Phase offset problem, we use a blind adaptive algorithm called the constant modulus derotator (CMD) algorithm based on condtant modulus algorithm (CMA). Moreover, unlike many known subspace (SS) methods or cross relation (CR) methods, our proposed algorithms do not require channel order estimation. Therefore, our algorithms are robust to channel order mismatch.

• 한국통신학회논문지
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• 제21권1호
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• pp.59-66
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• 1996

In this paper, we present a new effective algorithm for element failure compensation of Generalized Sidelobe Canceller (GSC). While the GSC is well formulated, little works have been done on array element compensation in the presence of faulty elements. Element failure changes the problem of a linearly equally spaced array into that of an unequally spaced array. Typical research approaches have been directed at using search techniques to optimize unequally spaced arrays. The proposed algorithm matches the linear constraint conditions and the general shape of the desired beam pattern at the expense of an increase of beam-width in the overall main lobe. Numerical results are included to demonstrate the capability of compensation for various situations.

• Journal of Power Electronics
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• 제9권5호
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• pp.748-756
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• 2009

This paper presents a compensation algorithm for position error due to an amplitude imbalance between resolver output signals. Resolvers are typically used to obtain absolute position information for motor drive systems in severe environments. Position error is caused by an amplitude imbalance of the resolver output signals. As a result, the d- and q-axis currents of synchronous reference frame have periodic ripples in the stator fundamental frequency in permanent magnet synchronous motor (PMSM) drive systems. Therefore, this paper proposes a compensation algorithm to reduce the position error generated by the amplitude imbalance. The proposed method does not require any additional hardware, and reduces computation time with a simple integral operation according to rotor position. In addition, the position error can be directly compensated for by the estimated position error. The effectiveness of the proposed compensation algorithm is verified through several simulations and experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.661-665
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• 2000

In this study, the control of mounting system for MLGA package was developed using machine vision for the control of rotating position compensation and mounting position of X-Y table. Two type of material (polymer, alumina )were used for the dielectric insulator of the MLGA. And the illumination system and the algorithm of position compensation that be suitable for these materials was developed. Also, the position control order that compensated by machine vision actuated to micro stepping motor and X-Y servo motor by controlled PC and mounted the MLGA on PCB in resolution to$\pm10\mum$ .

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.841-847
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• 1999

For successful assembly of flexible parts, informations about their deformation as well as possible misalignments between the holes and their mating parts are essential. Such informations can be acquired from visual sensors. For robotic assembly, the corrective assembly motion to compensate for such misalignments has to be determined from the measured informations. However, this may not be simply derived from the measured misalignment alone because the part deformation progressively occurs during misalignment compensation. Based on the analysis of flexible parts assembly process, this paper presents a neural net-based inference system that can infer the complex relationship between the corrective motion and the measured information of parts deformation and misalignments. And it verifies the performance of the implemented inference system. The results show that the proposed neural net-based misalignment compensation algorithm Is effective in compensating for the lateral misalignment, and that it can be extended to the assembly tasks under more general conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.234-236
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• 2006

Because of its long measurement range and ultra-precise resolution. the heterodyne laser interferometer systems are very common in various industry area such as semiconductor manufacturing. However the periodical nonlinearity property caused from frequency mixing is an obstacle to improve the high measurement accuracy in nanometer scale. In this paper to minimize the effect of nonlinearity, we propose an adaptive nonlinearity compensation algorithm. We first compute compensation parameters using least square (LS) with the capacitance displacement sensor as a reference input. We then update the parameters with recursive LS (RLS) while the values are optimized to modify the elliptical phase into circular one. Through comparison with some experimental results of laser system, we demonstrate the effectiveness of our proposed algorithm.

• 한국정밀공학회지
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• 제18권11호
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• pp.161-167
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• 2001

In this study, the control of mounting system for MLGA package was developed using machine vision for the control of rotation position compensation and mounting position of X-Y table. Two types of materials, polymer and alumina, were used for the dielectric insulator of the MLGA. The illumination system and the algorithm of position compensation which is suitable for these materials was developed. We found that the mounting accuracy enough to the degree of${\pm}10{\mu}m$ when MLGA was mounted on the PCB.

• 융합신호처리학회논문지
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• 제5권4호
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• pp.287-293
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• 2004

본 논문은 밝기 변화가 심한 비디오 시퀀스에 대해 효율적인 움직임 보상 알고리즘을 제안한다. 제안한 알고리즘에서는 화면간의 밝기 변화 변수들을 추정하고 지역적인 움직임 보상을 수행한다. 밝기 변화가 심한 화면을 검출하기 위해 연속되는 두 프레임간의 히스토그램의 크로스 엔트로피를 계산하여 밝기 변화가 심한 화면을 그렇지 않은 화면과 나누어 밝기 변화가 심하지 않은 경우에 발생할 수 있는 불필요한 계산량을 줄였다. 밝기 변화가 심한 비디오 시퀀스에 대한 실험결과 제안한 알고리즘은 기존의 알고리즘에 비해 적은 계산량으로 높은 PSNR (peak signal to noise ratio) 성능을 나타내었다.

• 한국통신학회논문지
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• 제39C권1호
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• pp.9-16
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• 2014

본 논문에서는 이동객체의 위치인식 정확도 향상을 위하여 최소자승법을 적용한 이동객체 위치인식 보정 알고리즘을 제안하고, 성능을 분석하였다. 제안한 보정 알고리즘은 일정한 속도로 이동 중인 이동객체의 거리 값들을 TMVS (TWR Minimum Value Selection) 기법으로 측정 한 후, 이 값들을 사용하여 삼변측량법으로 이동객체의 위치를 측정하고, 최소자승법을 적용하여 위치인식 값을 보정한다. 실험결과, 시나리오 1 및 2에서 제안하는 보정알고리즘을 적용한 위치인식의 성능은 기존의 삼변측량법을 적16용한 위치인식의 성능에 비해 위치인식 정확도가 시나리오별 각각 58.84%, 40.28% 개선됨을 확인하였다.