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In order to reduce the clock offset caused by network delay jitter, network asymmetry, clock drift and clock frequency difference in the clock synchronization process of IEEE1588, a modified Strong Tracking Adaptive Kalman Filter (MSTAKF) algorithm was proposed. The Kalman filter model established by the algorithm is based on clock offset, network delay, frequency deviation and asymmetry ratio. The filter includes the modified strong tracking algorithm based on fuzzy logic and hypothesis test proposed in this paper, which can effectively eliminate the influence of outliers, and finally make the model tracking effect better. In addition, the modified Sage‐Husa algorithm based on Cholesky decomposition is also included, which makes the measurement noise more stable and ensures the positivity of the measurement noise covariance. The experimental results show that the proposed MSTAKF is smoother than Karman filter (KF), Sage‐Husa adaptive Kalman filter (AKF) and strong tracking Sage‐Husa adaptive Kalman filter (STAKF). Compared with these filter algorithms after testing in the LAN environment, the precision improvement and accuracy rate are significantly improved. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, a new adaptive vector directional distance filter (AVDDF) is proposed. The AVDDF filter is developed to remove the 'salt and papper' impulsive noise in color images. This algorithm consists in first step to detect pixels that are likely to have been contaminated with noise by using a threshold value. In second step, after recognizing the corrupted pixels, the smallest angular‐magnitude distance is used to replace the noisy pixels. The proposed filter is tested with several standard color images which are contaminated with various levels of 'salt and pepper' impulsive noise (3%, 5%, 10%, 20% and 30%). The performance of the proposed filter is measured with peak signal‐to‐noise ratio (PSNR) and normalized color difference (NCD). The simulation results show that the proposed filter permits to ameliorate the performance of the classic vector directional distance filter (VDDF). Indeed, it provides an improvement by an average of 5% and 26% in the PSNR and NCD relative to the VDDF filter, respectively, with a small increase in the execution time by 6%. Besides, the AVDDF filter allows also an enhancement by an average of 2% and 14% in the PSNR and NCD relative to adaptive vector median filter (AVMF), respectively. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In view of the poor performance of the traditional adaptive filtering algorithm in identifying sparse systems under impulse noise, an affine projection maximum correntropy criterion with compound inverse proportional function (APMCCCIPF) algorithm is proposed in this paper, and the compound inverse proportional function approaching l0 norm is introduced into the traditional affine projection maximum correntropy criterion (APMCC) algorithm. The fixed step‐size APMCCCIPF algorithm cannot obtain faster convergence speed and lower steady‐state error at the same time, and the most effective method to solve this contradiction is to change the fixed step‐size in the algorithm to a variable step‐size. Further, a variable step‐size factor is constructed in the APMCCCIPF algorithm, and a novel variable step‐size APMCCCIPF algorithm is proposed. A modified Gaussian function, which can resist impulse noise interference, is applied to adjust the step‐size change. Besides, the convergence and complexity of the proposed algorithms are analyzed. In the simulation of sparse system identification and echo cancellation under impulsive noise, the proposed algorithms not only achieve a lower and faster convergence rate, but also obtain a lower steady‐state error. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This letter proposes an adaptive feature extraction method based on mathematical morphology for fault detection and location on transmission line. Multi‐scale morphological operation is designed where triangular structural elements are employed with the heights adjusted adaptively according to the input signal. Extensive simulation studies were carried out under different fault conditions, and the results demonstrated the effectiveness of the proposed method. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This study proposes an extension of the subband adaptive filtering technique to distributed active noise control systems and the details of the algorithm are presented. The computational requirements and convergence performance are examined for a network with a ring topology without constraints in communication. The proposed algorithm divides the signal of each node into several subbands to reduce the dynamic range of the spectrum and consequently accelerate the convergence speed. Since the subband decomposition contains a decimation process, the computational complexity is reduced as the number of subbands is increased. Simulations are conducted to compare different algorithms and an 8‐node network is studied in terms of noise reduction performance. The results demonstrate the efficacy of the proposed algorithm for broadband active noise control and the convergence speed could be improved compared to the distributed multiple error filtered‐x (DMEFxLMS) algorithm. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Manually monitoring the safety of personnel working on high‐voltage lines is difficult and unreliable. To overcome this problem, this paper proposes an online high‐voltage live safety monitoring and early warning system based on spatial cross‐border prevention. To develop the proposed system, following analysis of high‐voltage typical live working modes and the minimum approach distance, we divide the safe operation space and use a time‐of‐flight (TOF) depth camera to measure the live working distance in real time. This enables us realize safety early warning by detecting the boundary crossing and intrusion of the safe operation space. Subsequently, we analyze the ambient light and noise that affect the imaging quality of the TOF camera, evaluate the confidence of the depth image pixels, and apply a purpose‐designed adaptive filter guided by a confidence map to repair the depth images. The results of field experiments conducted verify that the proposed system accurate and reliable of this system through field experiments. Compared with manual observations, the system can significantly improve the effectiveness of real‐time live working safety monitoring, and can effectively prevent the occurrence of live working personal injury accidents. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

In this work, we introduce an adaptive variable‐step size normalized least mean squares algorithm to be used in finite impulse response structures. In our proposal, the step size is adjusted according to the cross‐correlation between the squared output error of the adaptive filter and the near‐end input signal. We show that the step increases or decreases as the error increases or decreases. This behavior is used to update the filter coefficients in the proposed adaptive filter. The proposed algorithm is named VSS‐CR, after variable step size based on cross‐correlation. This proposal was evaluated using computer simulations, and the obtained results show that it achieves higher levels of echo return loss enhancement and less misalignment than other algorithms. We identified a trade‐off between steady‐state performance and convergence time; the VSS‐CR achieves higher levels of echo reduction, but it takes some more time to reach its mean square error steady‐state value. This algorithm can be used in acoustic echo canceling in public switched telephone networks. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Taking the TFC35 electric forklift as the research object, we analyze the movements and forces of the forklift in three directions: yaw, lateral movement, and roll. Combined with the load transfer formula of the forklift and the nonlinear and linear tire model, the formula for lateral force of the four tires of forklift is deduced, and the nonlinear and linear three‐degree‐of‐freedom (3DOF) forklift dynamics model is established. Because the sideslip angle of the forklift is not easy to measure directly, based on the linear 3DOF forklift model, we take the yaw rate and lateral angle as the observation variables and consider the influence of model error. An adaptive Kalman filter is designed to estimate the sideslip angle of the forklift. In order to improve the accuracy of estimation, an online optimization strategy of the adaptive Kalman filter based on genetic algorithm with an adaptive factor is proposed. Simulation results show the effectiveness of the proposed method. In combination with the forklift reference model, the rear wheel angle of the forklift is corrected by comprehensive proportional feedback of yaw rate and the sideslip angle, and the active steering system for a steering‐by‐wire forklift is designed. Simulation and test results show that the control strategy of forklift's active steering system can improve its driving stability and handling performance. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper proposes a method of realizing an adaptive normalized ARMA lattice filter. This filter was proposed in a previous paper and can be realized with an arbitrary ARM A order and with all the lattice coefficients less than one. Furthermore, these coefficients are equal, so the structure is simplified. The adaptive realization method proposed in this paper retains these features. In addition, we perform spectral estimation of a time-varying signal with frequency weighting and model identification of an unknown input system. In our paper we describe an experiment with a real speech signal to prove that our algorithm can be used for frequency-weighted spectral estimation. The use of real data to perform spectral estimation has not been attempted in other references. [ABSTRACT FROM AUTHOR]

In the SLC (sidelobe canceler) which automatically suppresses the interference signals received by the sidelobe of the main antenna, there is a problem of suppression of the desired signal in addition to the interference signal if the desired signal power in the auxiliary antenna is larger than the receiver noise power and if the number of received interference signal is smaller than that of the auxiliary antennas. In this paper, an SLC is proposed in which the number of auxiliary antennas is adjusted automatically to be equal to that of the interference signals so that the problem of suppression of the desired signal is prevented. It is assumed here that both the desired signal and the interference signals have narrow bandwidths. In this SLC, with a view to adjusting the number of auxiliary antennas and the weights at the same time, the Gram-Schmidt SLC (GS-SLC) is used so that a sudden change of the input-output signal power ratio of the Gram-Schmidt processor is detected and the number of auxiliary antennas are made to coincide with that of the received interference signals. By way of a computer simulation, the fundamental characteristics of the present GS-SLC are evaluated. It is confirmed that the desired signal preservation property is improved in comparison with the conventional SLC. [ABSTRACT FROM AUTHOR]