• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.150-158
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• 2010

Filtering is necessary for the SRC(sample rate converter), that is used to change the sampling rate of a digital signal. The larger the conversion ratio of the sampling rate becomes, the more signal processing is needed for the filter, which means more complexity on realization. Thus it is important to reduce the amount of signal processing for the case of substantial conversion ratios. In this paper it is presented an efficient design method of a multistage FIR(finite impulse response) filter, with which the rate conversion occurs in stages rather than in one step. In this method, filter searching is performed exhaustively over all possible factorization of the conversion ratio, and also the filter complexity is measured based on direct realization rather than on estimation. It has been shown a designed multistage filter to have a less number of multiplications for filtering operation in comparison with a conventionally designed one. It has also been found that by allowing some variations of the filter architecture such as a halfband filter or a filter with multiple transition bands, the number of multiplications can be reduced further.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2005.11a
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• pp.278-281
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• 2005

본 논문에서는 백색 잡음이 첨가된 오디오 신호로부터 잡음을 추정하고 이에 따른 지각 필터 보정을 통한 적응적 지각 필터의 속도 개선 알고리즘을 제안한다. 제안된 잡음 추정 알고리즘은 고주파 구간에서 획득한 잡음 에너지를 사용하여 지각필터를 구성하고 일정 대역에서 추정된 기울기를 고주파 영역에 적용함으로써 전 대역의 잡음 에너지를 효과적으로 제거할 수 있게 되며 필터의 속도 향상에도 크게 기여하게 된다. 이는 기존의 적응지각필터와의 비교를 위하여 수행속도 및 SSNR, NMR 비교를 수행하였고 그 결과를 통하여 성능 개선을 확인할 수 있었다.

• Annual Conference of KIPS
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• 2007.11a
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• pp.1139-1142
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• 2007

Separable Gabor 필터는 기존의 2D Gabor 필터를 x축 성분과 y축 성분만을 지니는 두 개의 1D 필터로 나누어 각각 적용하는 방법으로 속도 향상을 가져왔으며, 지문인식 등에서 사용되어왔다. 하지만 정맥과 같은 경우에는 지문의 융선들 보다 더 굵기 때문에 필터의 크기 또한 매우 커진다. 따라서 Separable Gabor 필터의 경우도 지문에서만큼의 빠른 속도를 내지는 못한다. 본 논문에서는 Separable Gabor 필터 보다 더욱 고속의 연산이 가능한 Separable Symmetric Gabor 필터를 제안하였다. 이 필터는 사선 방향으로의 특징을 강조함에 있어 동시에 대칭이 되는 각도의 특성까지 강조하고, 회선 과정에서 필터의 방향 값을 고려하지 않기 때문에 인덱스 계산이 매우 단순해져 기존의 Separable Gabor 필터보다 처리 속도를 향상시킬 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8C
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• pp.806-815
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• 2006

It is studied to design a low pass filter of the SRC(sample rate converter), which is used to change the sampling rate of digital signals such as in digital modulation and demodulation systems. The larger the conversion ratio of the sample rate becomes, the more signal processing is needed for the filter, which corresponds to the more complexity in circuit realization. Thus it is important to reduce the amount of signal processing for the case of high conversion ratio. In this paper it is presented a design method of a two-stage cascaded FIR filter, which proved to have reduced amount of signal processing in comparison with a conventional single-stage one. The reduction effect of signal processing turned out to be more noticeable for larger value of conversion ratio, for instance, giving down to 72% in complexity for the conversion ratio of 32. It has been shown that the reduction effect is dependent to specific combination of conversion ratios of the cascaded filters. So an exhaustive search has been performed in order to obtain the optimal combination for various values of the total conversion ratio. In this paper every filter is considered to be implemented in the form of a polyphase FIR filter, and its coefficients are determined by use of the Parks-McCllelan algorithm.

• Clean Technology
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• v.5 no.1
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• pp.30-41
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• 1999

The experimental set-up with a 1m long ceramic candle filter of Schumacher(Germany) was built in this work. The dust velocity field around the filter was measured using PDPA. The effects of dust cake layer and dust inlet position on the dust velocity field were also analyzed. It was found that the filtration velocity decreases as the dust cake builds up on the filter. The filtration velocity largely decreases around the filters near the dust inlet since the dust cake develops fast there. The average dust velocity on the filter due to the pressure difference through the filter was measured to be 0.28m/s. More uniform dust velocity field around the filter was obtained when feeding dust in a lower position of the pressure vessel.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.193-196
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• 1999

본 논문은 음향 임펄스를 모델링하는데 코사인 변조된 필터 뱅크와 Decimation을 이용하여 수렴 속도를 개선하는 방법을 제안하고 이를 잡음제거에 응용하였다. 제안된 구조는 입력신호를 필터뱅크를 이용하여 각 서브밴드로 분할한 후 필터 입력신호의 고유벡터의 최대값과 최소값의 비를 줄이고 필터의 탭수를 줄이기 위해서 decimation을 행한다. 그리고 서브밴드대역의 샘플링 주파수를 낮추어 신호 스펙트럼을 확장시켜 이를 적응필터에 입력하여 수렴속도를 향상시켰다. 실험 결과, Colored잡음의 경우 LMS 알고리즘보다 제안된 방법이 MSE(Mean Square Error)는 좋지는 않았다. 실제 음향시스템의 모델링에는 거의 같은 MSE을 갖으며, 수렴 속도에는 모두 빠른 성능을 보였으며, 이를 음질향상에 적용하여 향상된 음질을 얻을 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.967-972
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• 2012

In order to implement good control of the permanent magnet synchronous motor(PMSM), the exact speed and rotor position information is needed.Recently, many studies have performed about sensorless speed control of the PMSM. This paper proposed sensorless speed controls of PMSM by using the Unscented Kalman Filter(UKF).The UKF is designed to eliminate the noise and get to the accuracy value and deals with the estimation of the speed and the rotor position of PMSM. Simulation and experiment have been performed for the verification of the proposed algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.1013-1020
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• 2011

This paper deals with the tracking problem of a moving target using multiple unmanned aerial vehicles. A decentralized extended information filter is designed to cooperatively estimate the position and the velocity of the moving target. The extended information filter is adopted to consider the range and the line-of-sight angle as measurement data. The decentralized scheme is applied to enhance the estimation performance using the information provided by other vehicles. Numerical simulation is performed to verify the tracking performance of the proposed decentralized filters.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.434-436
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• 1997

본 연구에서는 저속에서 발생하는 측정잡음에 대한 문제를 불규칙 확률시스템으로 고려하여 Kalman 필터를 관측자로서 사용하고 고속에서뿐만 아니라 저속에서의 위치와 속도 추정성능을 향상시키고자 한다. Kalman 필터는 확률적 외란을 포함하고 있는 동적시스템에 적용되는 최적상태 추정자이다. 또한 이 Kalman 필터는 외란을 가지는 이산형 실시간 동적 처리 시스템에서 최적의 미지 상태를 추정하기 위해 선형, 불편향, 그리고 최소 오차분산 회귀형 알고리즘을 제공한다. 또한, MRAS(Model Reference Adaptive System) 방법을 이용하여 모터와 부하에 대응되는 기계적 시정수를 동정한다. 이 방법은 기계적인 시정수가 알려지지 않은 시스템에 적용하여 위치와 속도의 추정을 가능하게 하기 위해서이다. 더욱이 동정의 결과를 이용하여 Kalman 필터 알고리즘에 적용한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.995-1001
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• 2012

This paper compares the performance of several tracking filters, namely, alpha-beta filter, Kalman filter and TBM tracking filter for ballistic target tracking problem using multi-function radar. Every of three tracking filters suggested was tested on simulator developed in accordance with TBM trajectory and MFR RSP measurement. The result shows the method using TBM tracking filter gives 75.3 % decreased velocity RMS error than alpha-beta filter. After initialization, the RMS error of range and velocity of the proposed filter is also smaller than the Kalman filter. Finally the proposed filter is suitable for high-speed TBM tracking due to the stable angle tracking accuracy.