Bearing and gear are essential components in gearbox, which is easily damaged and breaks down. Thus gearbox compound fault diagnosis has become a challenging topic in recent decades. Both bearing and gear faults in th...
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ISBN:
(纸本)9781467392204
Bearing and gear are essential components in gearbox, which is easily damaged and breaks down. Thus gearbox compound fault diagnosis has become a challenging topic in recent decades. Both bearing and gear faults in the gearbox tend to result in different transient impulse responses in the vibration signal and therefore it is necessary to present a method whose main task is to extract the different fault features. In this paper, a sparse representation method combining majorizationminimization (MM) algorithm and different wavelet bases is proposed to resolve the problem. Through the proposed method, different transients buried in the noisy signal can be converted into sparse coefficients. Both the simulation study and the practical application show the proposed method is effective in extracting gearbox compound fault features.
Orthogonal frequency division multiplexing (OFDM) systems are susceptible to impulsive noise;in essence, if the impulsive noise is not addressed adequately, system performance loss intensifies by the indelible impairm...
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One objective of this paper is to propose a novel class of sequence pairs, called "quasi-orthogonal Z-complementary pairs (QOZCPs)", each depicting Z-complementary property for their aperiodic auto-correlati...
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One objective of this paper is to propose a novel class of sequence pairs, called "quasi-orthogonal Z-complementary pairs (QOZCPs)", each depicting Z-complementary property for their aperiodic auto-correlation sums and also having a low correlation zone when their aperiodic cross-correlation is considered. Construction of QOZCPs based on Successively Distributed algorithms under majorizationminimization (SDAMM) is presented. Another objective of this paper is to apply the proposed QOZCPs in fully polarimetric radar systems and analyse the corresponding ambiguity functions. It turns out that QOZCP waveforms are much more Doppler resilient than the known Golay complementary waveforms.
In this paper, sequences with low local ambiguity functions are presented by analyzing the matrix-valued ambiguity function in a fully polarimetric radar system, and then generated by majorizationminimization algorit...
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ISBN:
(纸本)9781728116693
In this paper, sequences with low local ambiguity functions are presented by analyzing the matrix-valued ambiguity function in a fully polarimetric radar system, and then generated by majorization minimization algorithm. The two sequences, formed from the obtained Quasi Z-complementary pair whose transmission orders are determined by the Prouhet-Thue-Morse sequence and the Alamouti matrix, can result in a low local auto-ambiguity function in a modest Doppler shift interval and a very low local cross-ambiguity function among all Doppler shifts.
The Sylvester or smallest enclosing circle problem involves finding the smallest circle enclosing a finite number of points in the plane. We consider generalized versions of the Sylvester problem in which the points a...
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The Sylvester or smallest enclosing circle problem involves finding the smallest circle enclosing a finite number of points in the plane. We consider generalized versions of the Sylvester problem in which the points are replaced by sets. Based on the log-exponential smoothing technique and Nesterov's accelerated gradient method, we present an effective numerical algorithm for solving these problems.
In this paper, we review an auxiliary function approach to independent component analysis (ICA) and independent vector analysis (IVA). The derived algorithm consists of two alternative updates: 1) weighted covariance ...
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ISBN:
(纸本)9781628416121
In this paper, we review an auxiliary function approach to independent component analysis (ICA) and independent vector analysis (IVA). The derived algorithm consists of two alternative updates: 1) weighted covariance matrix update and 2) demixing matrix update, which include no tuning parameters such as a step size in the gradient descent method. The monotonic decrease of the objective function is guaranteed by the principle of the auxiliary function method. The experimental evaluation shows that the derived update rules yield faster convergence and better results than natural gradient updates. An efficient implementation on a mobile phone is also presented.
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