• 한국정보처리학회논문지
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• 제6권10호
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• pp.2830-2837
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• 1999

Image processing steps are consist of image acquisition, preprocessing, region, segmentation and recognition. But image corrupted commonly by noise reduction methods, many filters were proposed like mean filter, median filter, weighted median filter, Cheikh filter, and Kyu-cheol lee filter as spatial noise reduction filtering. We propose a new edge detection algorithm so that we find out edge existence and nonexistence. In non-edge area, we selectively apply weighted median filter based upon using information of difference value between weighted median filter's value and center pixel's value. As a result, we finally prove a better performance of noise reduction by applying adaptive weighted median filter and improvement of processing time through using simple algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1679-1683
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• 1997

In this paper a linear Kalman filter for calibration of gimballed inertial navigation system(GINS) is designed and its performace is analyzed through the simulation with a real navigation data. Simulation results show that the proposed Kalman filter gives a good performance to calibrate the sensor errors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1137-1138
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• 2013

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.269-274
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• 1986

A continuous-time modified gain extended Kalman filter (MGEKF) is developed in an effort to extend the discrete-time results of 1) and 2). Used as an observer, it is globally exponentially convergent. For stochastic system, the stability of the MGEKF is proven under certain conditions. The performance of the MGEKF is compared with that of the EKF for a particular nonlinear system where the fininate dimensional optimal filter exists.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.185-185
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• 2000

This paper designs an interference mitigation filter for GPS receiver using a time-domain signal processing techniques (Adaptive Transversal filter). ATF is designed using verilog and simulated using COSSAP for evaluating its performance.

• Journal of Communications and Networks
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• 제9권1호
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• pp.18-27
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• 2007

The conventional normalized least mean square (NLMS) algorithm is the most widely used for adaptive identification within a non-stationary input context. The convergence of the NLMS algorithm is independent of environmental changes. However, its steady state performance is impaired during input sequences with low dynamics. In this paper, we propose a new NLMS algorithm which is, in the steady state, insensitive to the time variations of the input dynamics. The square soot (SR)-NLMS algorithm is based on a normalization of the LMS adaptive filter input by the Euclidean norm of the tap-input. The tap-input power of the SR-NLMS adaptive filter is then equal to one even during sequences with low dynamics. Therefore, the amplification of the observation noise power by the tap-input power is cancelled in the misadjustment time evolution. The harmful effect of the low dynamics input sequences, on the steady state performance of the LMS adaptive filter are then reduced. In addition, the square root normalized input is more stationary than the base input. Therefore, the robustness of LMS adaptive filter with respect to the input non stationarity is enhanced. A performance analysis of the first- and the second-order statistic behavior of the proposed SR-NLMS adaptive filter is carried out. In particular, an analytical expression of the step size ensuring stability and mean convergence is derived. In addition, the results of an experimental study demonstrating the good performance of the SR-NLMS algorithm are given. A comparison of these results with those obtained from a standard NLMS algorithm, is performed. It is shown that, within a non-stationary input context, the SR-NLMS algorithm exhibits better performance than the NLMS algorithm.

• 한국인터넷방송통신학회논문지
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• 제13권1호
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• pp.221-227
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• 2013

최근 인터넷이 주 정보원으로 작용하고 인터넷의 보급이 확산되는 정보화시대에 인터넷 망이 닿지 않는 지역의 Last Mile Solution에 적합한 대안으로서 전력선 통신에 관한 연구가 진행되고 있다. 하지만, 전력선 통신은 전력을 전송하도록 설계되었기 때문에 높은 고주파 신호를 보내게 되면 부근의 무선통신 서비스에 영향을 주게 된다. 이러한 간섭을 제거하기 위해서 일반적인 방법으로는 Notch filter를 주로 사용한다. 본 논문에서는 WDF 방식을 적용한 동적 고성능 Notch filter를 MATLAB을 통해 성능을 확인하였고 TI사의 TMS320C6416T DSP 보드를 이용하여 구현하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제4권3호
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• pp.163-168
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• 2015

Many IP address lookup approaches employ Bloom filters to obtain a high-speed search performance. Especially, it has been recently studied that the search performance of trie-based algorithms can be significantly improved by adding Bloom filters. In such algorithms, the number of trie accesses can be greatly reduced because Bloom filters can determine whether a node exists in a trie without actually accessing the trie. Bloom filters do not have false negatives but have false positives. False positives can lead to unnecessary trie accesses. The false positive rate must thus be reduced to enhance the performance of lookup algorithms applying Bloom filters. One important characteristic of trie-based algorithms is that all the ancestors of a node are also stored. The proposed algorithm utilizes this characteristic in reducing the false positive rate of a Bloom filter without increasing the size of the memory for the Bloom filter. When a Bloom filter produces a positive result for a node of a trie, we propose to check whether the ancestors of the node are also positives. Because Bloom filters have no false negatives, the negatives of any of the ancestors mean that the positive of the node is false. In other words, we propose to use more Bloom filter queries to reduce the false positive rate of a Bloom filter in trie-based algorithms. Simulation results show that querying one ancestor of a node can reduce the false positive rate by up to 67% with exactly the same architecture and the same memory requirement. The proposed approach can be applied to other trie-based algorithms employing Bloom filters.

• 한국정보통신학회논문지
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• 제15권12호
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• pp.2511-2520
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• 2011

본 논문은 다중 센서 융합의 성능을 높이기 위해 적응형 퍼지-칼만 필터를 적용하고 교차검증법(cross-validation)으로 퍼지시스템 입 출력 소속 함수의 매개변수를 조정하는 방법을 제안한다. 적응형 퍼지-칼만 필터는 가속도의 변화량과 칼만 필터의 잔여오차를 입력으로 시스템잡음, 측정잡음을 추정하여 칼만 이득을 변화시킨다. 적용된 퍼지-칼만 필터는 잡음들을 가우시안 분포로 가정한 이전 방법과 비교하여 비선형/비가우시안 잡음에 강인한 추정 결과를 보여준다. 본 논문에서 제안한 퍼지-칼만 필터를 평가하기 위해 가속도센서/자이로센서를 융합하여 2축 자세추정시스템(Attitude Heading Reference System)을 설계하였고 무인항공기에 사용되는 자세추정센서 NAV420CA-100과 비교하여 성능을 검증하였다.

• 한국가스학회지
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• 제13권4호
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• pp.1-7
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• 2009

최근 연료경제성 및 강화되는 배출가스 규제를 만족하기 위하여 대체연료의 하나인 LPG에 대한 수요가 증가하고 있다. 현재 LPG 차량에 적용되고 있는 제3세대 LPG 연료공급방식인 LPLi(Liquid Phase LPG Injection) 시스템은 가솔린 차량과 비교하여 배출가스는 적게 배출하면서 동등한 출력을 낼 수 있게 하는 핵심 기술이다. LPG 연료를 고압의 액상 상태로 공급하기 위해서는 LPG 펌프가 필요하다. 연료펌프의 성능을 저하 시킬 수 있는 연료 내 불순물을 제거하기 위하여 연료펌프에는 연료필터가 장착되어 있으며 장착되는 연료필터의 종류에 따라서 연료펌프의 성능도 변하게 된다. 본 연구에서는 임펠라 방식을 채택한 LPG 연료펌프에서 극세사, 이중메쉬, 외장형 필터의 세 가지 필터에서 부하별 토출성능 및 효율을 파악하였으며 온도 변화에 따른 펌프유량 변화를 측정하였다.