• Title/Summary/Keyword: Correlation filter

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Applications and analysis on the subband nonlinear adaptive Volterra filter (부대역 비선형 Volterra 적응필터의 응용과 성능분석)

  • Yang, Yoon Gi;Byun, Hee Jung
    • Journal of IKEEE
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    • v.17 no.2
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    • pp.111-118
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    • 2013
  • In this paper, the subband nonlinear adaptive Volterra filters are introduced and its analysis are presented. From the eigenvalue analysis of the input correlation matrix, we show that the proposed subband adaptive Volterra filter has superior convergence performance as compared to the conventional one, which shows that the it can be useful for the recently proposed subband nonlinear adaptive echo canceller. Also, the optimum filter in each subband are introduced and verified from the computer simulations.

Stochastic Model of the Bearing Estimator Using Cross-Correlation Method (상호상관관계를 이용한 방위탐지기의 확률적 모델)

  • 박상배;류존하;이균경
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.1
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    • pp.23-33
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    • 1994
  • In this paper, we propose a probabilistic model appropriate for the bearing estimator which uses cross-correlation method following a close investigation on real underwater acoustic bearing data. The well-known JPDA(Joint Probabilistic Data Association) filter is tuned to the underwater acoustic bearing estimation based on the result that the reliability of the bearing measurement is related to the amplitude of the cross-correlation peak. The proposed probabilistic model is shown to be adequate by presenting the results of the improved tracking performance of the modified filter for various real bearing data as well as artificially generated ones.

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A Fault Location Algorithm for a Transmission Line Using Travelling Waves (진행파를 이용한 송전선로의 고장점 표정 알고리즘)

  • Kang Sang-Hee;Kim Jin-Han
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.10
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    • pp.542-549
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    • 2004
  • The conventional fault location algorithms based on the travelling waves have an inherent problem. In cases of the close-up faults occurring near the relaying point and of the faults having zero degree inception angle of voltage signals, the conventional algorithms can not estimate an accurate fault distance. It is because the shapes of travelling waves are near sinusoidal in those cases. A new method solving this problem is presented in this paper. An FIR(Finite Impulse response) filter which makes high frequency components prominent and makes the power frequency component and dc-offset attenuated is used. With this method, the cross-correlation peak is to be very clear when a close-up fault or a fault having near zero-degree inception angle occurs. The cross-correlation peaks can be clearly distinguished and accurate fault location is practically possible consequently. A series of simulation studies using EMTP(Electromagnetic Transients Program) show that the proposed algorithm can calculate an accurate fault distance having maximum 2% or less error.

An Adaptive Image Quality Assessment Algorithm

  • Sankar, Ravi;Ivkovic, Goran
    • International journal of advanced smart convergence
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    • v.1 no.1
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    • pp.6-13
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    • 2012
  • An improved algorithm for image quality assessment is presented. First a simple model of human visual system, consisting of a nonlinear function and a 2-D filter, processes the input images. This filter has one user-defined parameter, whose value depends on the reference image. This way the algorithm can adapt to different scenarios. In the next step the average value of locally computed correlation coefficients between the two processed images is found. This criterion is closely related to the way in which human observer assesses image quality. Finally, image quality measure is computed as the average value of locally computed correlation coefficients, adjusted by the average correlation coefficient between the reference and error images. By this approach the proposed measure differentiates between the random and signal dependant distortions, which have different effects on human observer. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.

Characteristics of Spatial Coded Binary Phase Only Filter Applied by Simulated Annealing Algorithm (Simulated Annealing 알고리즘을 적용한 이진공간부호필터 특성)

  • 박성균;정창규;전석희;박한규
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.9
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    • pp.64-71
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    • 1994
  • In this study, optimizing BPOFs are encoded by Simulated Annealing algorithm that is widely used among the optimization algorithms. Two BPOFs are trained by digit patterns, 0~9, and the digits each having 4 intraclass patterns are multiplexed. When each digit is encoded by four bit binary code, from the results of computer simulation, the correlation pezk is shown at binary value 1 position among the spatially separated four positions at the correlation plane And then, the designed BPOFs are implemented by CGH technique. Through the optical correlation experiment, satisactory results are achieved, inspite of some experimental errors and information loss owing to the amplitude type CGH filter.

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Korean Alphabets Recognition Using the Modified CGH Multiplexed Matched Filter (변조된 CGH 다중 정합 필터를 사용한 한글 자모 인식)

  • Jeong, Jae Woo;Kim, Hong Man;Lee, Yong Tag;Kang, Min Ho
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.23 no.3
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    • pp.401-408
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    • 1986
  • In optical pattern recognition, incorrect discrimination may result from a relatively high cross correlation peak between similary shaped objects. In this paper, a new modified matched CGH(computer generated hologram) filter is proposed for reducing the cross-correlation without reducing the autocorrelation. Computer simulation and experimental results show that this new method can be used efficiently for optical Korean alphabets recognition. The signal to noise characteristics are analyzed on the correlation distdribution diagram.

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The design of the matched filter for CDMA rapid initial PN code synchronization acquisition using HW reuse scheme (CDMA 고속초기동기획득을 위한 HW 재사용에 의한 정합필터의 설계)

  • Lim, Myoung-Seob
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.11
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    • pp.28-36
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    • 1998
  • In the CDMA mobile communication system with asynchronous mode among base stations, the initial PN code acquisition method using a matched filter can be considered for the rapid PN code synchronization acquisition in the handoff region. In the model of the noncoherent QPSK/DS-SS under the Rayleigh fading channel, the mean acquisttion time of the matched filter is analyzed to have a shortened time in proportion to the length of matched filter to be compared with the serial correlation method. In this paper to improve the HW complexity of the conventional matched device which enables the repeated correlation process, is designed and its function is verified through the FPGAsimulation using Altera MaxPlus Ⅱ.

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Application of ALE for detection of rolling ball bearing defects in noisy environment (잡음환경에서 구름 볼 베어링의 결함검출을 위한 ALE의 적용)

  • 김영태;최만용;김기복;박해원;박정학;김종억;류준
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.86-91
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    • 2004
  • It is very important to detect the bearing defects in rotating machinery since the critical failure of bearing cause a machinery shutdown. However it is difficult to detect the vibration signal resulting from the initial defects of bearing because of the high level of broadband noise. A signal processing technique, called the adaptive line enhancer(ALE) as one of adaptive filter, is studied in this work. This technique is to eliminate broadband noise without a prior knowledge of the noise and signal characteristics. Also we propose the optimal methods for selecting the three main ALE parameters such as correlation length, filter order and adaptation constant used in the adaptative process. Vibration signals for three abnormal bearings, including inner and outer raceways and ball defects, were acquired from Anderon(angular derivative of radius on)meter. The experimental results showed that the proposed technique can reliably detect the bearing defective signals masked by broadband noise.

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Uncertainty Evaluation of Baseflow Separation Filter methods: A Case Study of the Urmia Lake Basin in Iran

  • Nezhad, Somayeh Moghimi;Jun, Changhyun;Parisouj, Peiman;Narimani, Roya
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.135-135
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    • 2022
  • In this study, we evaluated uncertainties in baseflow separation filter methods focusing on changes in recession constant (𝛼) values, which include Lynie & Holick (LH) algorithm, Chapman algorithm, Eckhardt filter, and EWMA filter. Here, we analyzed daily streamflow data at 14 stations in the Urmia Lake basin, Iran, from 2015 to 2019. The 𝛼 values were computed using three different approaches from calculating the slope of a recession curve by averaging the flow over all seasons, a correlation method, and a mean value of the ratio of Qt+1 to Qt. In addition to the 𝛼 values, the BFImax (maximum value of the baseflow index (BFI)) was determined for the Eckhardt filter through the backward filter method. As results, it indicates that the estimated baseflow is dependent upon the selection of filter methods, their parameters, and catchment characteristics at different stations. In particular, the EWMA filter showed the least changes in estimating the baseflow value by changing the 𝛼 value, and the Eckhardt filter and LH algorithm showed the highest sensitivity to this parameter at different stations.

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Performance Improvement of Stereophonic Acoustic Echo Canceler Using Non-linear Pre-processing Filter (비선형 전처리필터를 이용한 스테레오 음향 반향 제거기의 성능향상)

  • 박장식;정일규;손경식;김현태
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.3
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    • pp.264-273
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    • 2002
  • Adaptive filters cannot exactly estimate the echo path of the receiving room because of the cross-correlation of stereo signals. In this paper, a new pre-processing method reducing the cross-correlation without degradation of stereophony is proposed to enhance the performance of stereophonic acoustic echo canceller. To reduce the cross-correlation, absolutes of two orthogonal signals derived from each channel signals are added to original channel signals. Assuming that the power of each channel signal is larger than that of the cross-correlation, the computation of pre-processing can be reduced. As results of simulations, it is shown that the performance of stereo acoustic echo canceller with the proposed pre-processing method is better than that of conventional ones.