• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.88-95
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• 1999

Stack filters are a class of digital nonlinear filters with excellent properties for signal restoration. Unfortunately, present algorithms for designing stack filters with large window size are limited in applications by their computational overhead and serial nature. In this paper, new, highly-parallel algorithm is developed for determining a stack filter which minimizes the mean absolute error criterion. It retains the iterative nature of the present adaptive algorithm, but significantly reduces the number of required to converge to an optima filter. A proof is also give that the proposed algorithm converges to an optimal stack filter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.471-478
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• 2007

The SA fillers encompass a large class of filters based on order statistics as veil as linear FIR filters. Using SA later structure, it is possible to design linear and non-linear filters under a unified framework. In this paper SA filters are applied to an image smoothing problem for mixed noise. Original image is contaminated by Gaussian and impulsive noise. Optimal SA filters are designed and applied to contaminated image. The experimental result shows that SA filters outperform linear FIR and ordering-based nonlinear filters.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.379-386
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• 2005

This paper provides a rigorous theory for analysis of quantization effects and optimum filter bank design in quantized multidimensional subband filter banks. Even though subband filter design has been a hot topic for last decades, a few results have been reported on the subband filter with a quantizer. Each pdf-optimized quantizer is modeled by a nonlinear gain-plus-additive uncorrelated noise and embedded into the subband structure. Using polyphase decomposition of the analysis/synthesis filter banks, we derive the exact expression for the output mean square quantization error. Based on the minimization of the output mean square error, the technique for optimal filter design methodology is developed. Numerical design examples for optimum nonseparable paraunitary and biorthogonal filter banks are presented with a quincunx subsampling lattice. Through the simulation, $10\~20\;\%$ decreases in MSE have been observed compared with subband filter with no quantizers especially for low bit rate cases.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.3
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• pp.11-22
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• 2002

The design of optimal filter yielding optimal texture feature separation is a most effective technique in many torture analyzing areas, such as perception of surface, object, shape and depth. But, most optimal filter design approaches are restricted to the issue of computational complexity and supervised problems. In this paper, Our proposed method yields new insight into the design of optimal Gabor filters for segmenting multiple texture images. The optimal frequency of Gator filter is turned to the optimal frequency of the distinct texture in frequency domain. In order to show the performance of the designed filters, we have attempted to build a various texture images. Our experimental results show that the performance of the system is very successful.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.367-370
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• 1999

일반적 인 SAW 필터에서 발생하는 선형성의 한계 및 천이대역의 특성을 개선하기 위한 새로운 구조의 이중구조 사다리형 SAW 필터의 최적 설계 방법을 제시하고 그 가능성을 확인하였다. 이중구조 SAW 필터는 일반적인 사다리형 필터의 구조를 바탕으로 하되, 두 개의 서로 다른 필터가 각각 주어진 대역사양을 반반씩 만족시켜 전체의 필터특성이 구현될 수 있도록 하였다. 특히 고주파 대역에서 만족시키기 어려운 정재파비 및 뛰어난 천이대역 특성을 만족시킬 수 있는 장점을 가지며, 이를 위해 withdrawal 가중기법 및 기판상에 encp화된 마이크로 스티 립라인 인덕터를 이용하였다. 우선 이중 구조 필터구조를 결정한 후, microstrip 라인 인덕터의 위치 및 인덕턴스 변화에 따른 필터특성 변화를 살펴보았으며, 필터의 각종 형상변수의 변화에 따른 필터 특성변화를 조사하였다. 이상의 결과를 바탕으로 새로운 방법의 이중구조 SAW 필터의 설계방법을 제시하였으며 그 타당성을 검증하기 위해 1.8 GHz 대역의 RF 필터에 대한 설계 결과를 나타내었다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1666-1667
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• 2011

본 논문에서는 CSRR을 이용하여 0.5~1.5GHz 대역의 광대역 필터를 최적 설계 연구 하였다. Metamaterial의 일종인 CSRR은 LC 공진기 역할을 하며 전송선로와 결합하여 필터 특성을 나타낸다. 또한 높은 Q-factor의 특성을 갖기 때문에 협대역 대역통과 필터 특성을 갖는다. 이에 본 논문에서는 CSRR을 이용하여 광대역 대역통과 특성을 갑기 위해서 전송선로의 형태를 변형하고 진화알고리즘중 하나인 진화 전략기법을 이용하여 단일 셀의 최적 설계를 수행하였다. 이후 단위 셀을 다단으로 연결하여 최종 광대역 필터를 설계하였다. 본 논문에서 설계된 광대역 필터는 0.5~1.5GHz의 대역폭을 갖으며 00~00dB의 삽입손실을 갖는다. 그리고 저지대역에서 00~00dB의 저지 특성을 갖는다.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.311-320
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• 2003

The Optimal filter yielding optimal texture feature separation is a most effective technique for extracting the texture objects from multiple textures images. But, most optimal filter design approaches are restricted to the issue of supervised problems. No full-unsupervised method is based on the recognition of texture objects in image. We propose a novel approach that uses unsupervised learning schemes for efficient texture image analysis, and the band-pass feature of Gabor-filter is used for the optimal filter design. In our approach, the self-organizing neural network for multiple texture image identification is based on block-based clustering. The optimal frequency of Gabor-filter is turned to the optimal frequency of the distinct texture in frequency domain by analyzing the spatial frequency. In order to show the performance of the designed filters, after we have attempted to build a various texture images. The texture objects extraction is achieved by using the designed Gabor-filter. Our experimental results show that the performance of the system is very successful.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.7
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• pp.999-1008
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• 1993

동기추적 루프는 수신된 확산 부호의 동적 파형에 대한 추적을 수행함에 있어 AWGN 존재 하에서 낮은 동기추적 지터를 목적으로 설계되며, 전송지연에 대한 효율적인 추적을 위한 루프의 대역폭이 요구된다. 본 논문에서는 지연동기루프의 최적 설계를 위한 대역통과필터의 대역폭에 대하여 고찰하였다. NRZ 데이타의 경우 단극, 쌍극 및 이상적 Butterworth 대역통과 필터를 채용한 비코히어런트 BLL의 재곱손실을 구하였으며, 이를 통해 루프의 동기추적 지터를 최소화하는 대역통과필터의 최적의 대역폭을 주어진 데이타율과 수신비트에너지대 잡음밀도비에 대해 구하였다. 결과로서 NRZ 데이타의 경우 합리적인 대역통과필터의 최적대역폭이 존재함을 알 수 있으며, 아울러 DLL의 동기추적 지터에 대한 성능은 사용된 필터의 종류에 대해서는 비교적 민감하지 않음을 알 수 있다.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1159-1168
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• 2003

In this paper, a new wavelet filter design algorithm is proposed which optimizes energy compaction of transformed coefficients. The filter, designed by the proposed algorithm enhances the coding gain of the system with fixed quantizer by most unevenly distributed energy in transform domain. The coding gain function was extended to obtain the optimal filter coefficients in each stage. The experiments showed that the filter designed by proposed method outperforms conventional filters in energy compaction rate.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.549-554
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• 2012

In this paper, we consider the optimal fuzzy filter of nonlinear discrete-time with estimation error variance constraint. First, the Takagi and Sugeno(T-S) fuzzy model is employed to approximate the nonlinear system. Next, the error state is mean square bounded, and the steady state variance of the estimation error of each state is not more than the individual predefined value. It is shown that, the addressed problem can be carried out by solving linear matrix inequality(LMI) and some algebraic quadratic matrix inequalities. Finally, some examples are provided to illustrate the design procedure and expected performance through simulations.