• 한국군사과학기술학회지
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• 제16권3호
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• pp.285-294
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• 2013

In this paper, we present a tunable BPF with a novel structure. The filter is very useful to optimization of low frequency filter performance, because the fiilter has air-coils and tuning screws. This filter also has the merits of light weight and small size in comparison with conventional tunable filter at low frequency. This type filters are especially suitable for switched filter bank due to tuning structure. We designed 4 channel filter bank with two SP4Ts and 4 BPFs using novel structure. Tuning processes were subsequently executed. We obtained satisfactory performances as a result; consequently, the validity of our proposal was proved.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.276-280
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• 2016

A fixed rate speech coder based on the filter bank and the non-uniform sampling technique is proposed. The non-uniform sampling is achieved by the detection of inflection points (IPs). A speech block is band passed by the filter bank, and the subband signals are processed by the IP detector, and the detected IP patterns are compared with entries of the IP database. For each subband signal, the address of the closest member of the database and the energy of the IP pattern are transmitted through channel. In the receiver, the decoder recovers the subband signals using the received addresses and the energy information, and reconstructs the speech via the filter bank summation. As results, the coder shows fixed data rate contrary to the existing speech coders based on the non-uniform sampling. Through computer simulation, the usefulness of the proposed technique is confirmed. The signal-to-noise ratio (SNR) performance of the proposed method is comparable to that of the uniform sampled pulse code modulation (PCM) below 20 kbps data rate.

• 한국통신학회논문지
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• 제7권4호
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• pp.156-160
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• 1982

A Comb Filter(C.F.) is constucted with a N-stages one-dimensional B.B.D.(Bucket-Brigade Device) delay line. One channel of the B.P.F. (Band Pass Filter) Bank is experimented, which includes a R.F.(Recursie Filter) using S/H circuits cascaded to the C.F. This algorithm of the C.F.B.(Comb Filter Bank) becomes the parallel spectrum analyzer circuit. The algorithm has less number of multiplication than that of FFT and improves the SNR.

• 대한전자공학회논문지SP
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• 제41권6호
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• pp.279-283
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• 2004

음성신호의 스펙트럼으로부터 MFCC를 추출할 때, 일반적으로 필터뱅크의 처리과정에서 삼각형 형태의 필터를 사용한다. 그러나 더 나은 인식성능을 위해, 훈련 음성데이터의 스펙트럼에 PCA를 적용하여 필터뱅크의 필터형태를 최적화하는 PCA-optimized 필터뱅크 방법이 Lee et al. 에 의해 제안되었다. 본 논문에서는 대용량의 4연숫자 전화음성 DB를 사용하여PCA-optimized 필터뱅크 기반의 MFCC 특징파라미터를 추출하고 인식실험을 수행한 후, 기존의 삼각형 형태의 필터를 사용하는 MFCC와 각 대역별 로그에너지로 가중시켜서 얻어지는 MFCC와의 인식성능을 비교하였다. 실험결과, PCA-optimized 필터뱅크 기반의 MFCC 특징파라미터가 기존의 삼각형 형태의 필터뱅크 기반 MFCC에 비해 조금 향상된 인식률을 나타내었지만, 각 대역별 로그에너지로 가중치를 주어 얻어지는 MFCC보다는 인식률이 떨어졌다.

• 제어로봇시스템학회논문지
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• 제20권9호
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• pp.930-935
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• 2014

A Gabor filter is a linear filter used for edge detectionas frequency and orientation representations of Gabor filters are similar to those of the human visual system. In this thesis, we propose a pedestrian detection algorithm using a Gabor filter bank. In order to extract the features of the pedestrian, we use various image processing algorithms and data structure algorithms. First, color image segmentation is performed to consider the information of the RGB color space. Second, histogram equalization is performed to enhance the brightness of the input images. Third, convolution is performed between a Gabor filter bank and the enhanced images. Fourth, statistical values are calculated by using the integral image (summed area table) method. The calculated statistical values are used for the feature matrix of the pedestrian area. To evaluate the proposed algorithm, the INRIA pedestrian database and SVM (Support Vector Machine) are used, and we compare the proposed algorithm and the HOG (Histogram of Oriented Gradient) pedestrian detector, presentlyreferred to as the methodology of pedestrian detection algorithm. The experimental results show that the proposed algorithm is more accurate compared to the HOG pedestrian detector.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.413-418
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• 2003

In this paper, a new multirate optimal finite impulse response (FIR) filter is proposed for the signal reconstruction in the nosy filter bank systems. The multirate optimal FIR filter replaces the conventional synthesis filters and the Kalman synthesis filter. First, the generic linear model is derived from the multirate state space model for an autoregressive (AR)input signal. Second, the multirate optimal FIR filter is derived from the multirate generic linear model using the minimum variance criterion. This paper also provides numerical examples and results. The simulation results illustrate that the performance is improved compared with conventional synthesis filters and the proposed filter has advantages over the Kalman synthesis filter.

• The Journal of the Acoustical Society of Korea
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• 제15권2E호
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• pp.24-32
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• 1996

A rigorous theory for modeling, analysis, optimum nonseparable filter bank in multidimensional M-band quantized subband codec are developed in this paper. Each pdf-optimized quantizer is modeled by a nonlinear gain-plus-additive uncorrelated noise and embedded into the subband structure. We then decompose the analysis/synthesis filter banks into their polyphase components and shift the down-and up-samplers to the right and left of the analysis/synthesis polyphase matrices respectively. Focusing on the slow clock rate signal between the samplers, we derive the exact expression for the output mean square quantization error by using spatial-invariant analysis. We show that this error can be represented by two uncorrelated components : a distortion component due to the quantizer gain, and a random noise component due to fictitious uncorrelated noise at the uantizer. This mean square error is then minimized subject to perfect reconstruction (PR) constraints and the total bit allocation for the entire filter bank. The algorithm gives filter coefficients and subband bit allocations. Numerical design example for the optimum nonseparable orthonormal filter bank is given with a quincunx subsampling lattice.

• 대한전자공학회논문지
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• 제26권6호
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• pp.140-146
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• 1989

일반적으로 레이다 표적은 클러터 환경에 있으며 클러터 제거가 요구된다. 클러터는 지표, 기상 조건의 변화로 부터 발생되는 원하지 않는 레이다 반사파로 클러터의 통계적 특성은 시간, 거리 그리고 방향에 따라 변화함으로 효과적인 클러터 제거를 위하여 적응 신호 처리가 필요하다. 본 논문에서는 clutter whitening filter와 doppler filter bank를 이용한 클러터 제거 알고리듬을 제안하였으며 그 성능을 종래의 비적응 클러터 제거 알고리듬의 성능과 비교하였다. Clutter whitening filter 알고리듬 Burg가 제안한 최대 엔트로피 방법을 이용하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제1권1호
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• pp.55-64
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• 1997

We show that if an even length filter has the same length complementary filter in a generalized linear phase case, the complementary filter is unique, we find sufficient conditions for a unique existence of even length N complementary filter in a quadrature mirror filter bank, and we find all higher degree symmetric filters of length N + 4m which are complementary to a given symmetric filter of even length N.

• 전기학회논문지
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• 제65권1호
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• pp.179-193
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• 2016

In power quality monitoring, voltage fluctuation is one of the power quality problems, which cause light flickers. To determine the flicker severity, the flicker meter concept was developed in an IEC 61000-4-15 standard. Generally, voltage fluctuations are described as an amplitude modulation(AM). The flicker meter of IEC 61000-4-15 as an international standard for flicker measurement recommends square demodulation method to detect flicker signals from voltage fluctuation signals. This paper suggests a new effective method using filter bank to detect and estimate flicker signals, which do not need square demodulation. For the accurate detection of flicker signals, the filter bank is designed with a full consideration of the spectrum characteristics of voltage fluctuation signals described as AM. The frequency and magnitude of the detected flicker signals are estimated using recursive method. Computer simulations were performed on synthesized signals to prove validity of the proposed method.