A New Wavelet Modulus Maximum Method for Noise Reduction of Chaotic Signals

Author(s):  
Guo-shi Yang ◽  
Yun-xia Liu
2012 ◽  
Vol 19 (6) ◽  
pp. 1837-1842 ◽  
Author(s):  
S. Jafari ◽  
S.M.R. Hashemi Golpayegani ◽  
A.H. Jafari

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhigang Feng ◽  
Xuezai Pan ◽  
Guoxing Dai ◽  
Hongguang Liu

In order to test the differences in the morphology characterization of rock fracture surfaces under different loading directions and rates, the following three steps are operated. Firstly, using Brazilian test, the Brazilian discs are loaded to fracture under different loading modes. Secondly, each rock fracture surface is scanned with a highly accurate laser profilometer and accordingly the coordinates of three lines on every rock fracture surface and three sections of every line are selected to analyze their fracture morphology characterization. Finally, modulus maximum method of wavelet transform, including a new defined power algorithm and signal to noise ratio, and fractal variation method are used to determine the differences in rock fracture surfaces’ morphology characterization under different loading directions and rates. The result illustrates that both modulus maximum and fractal variation method can detect anisotropy of rock fracture failure. Compared to modulus maximum method, fractal variation method shows stronger sensitivity to the change of loading rates, which is more suitable to differentiate the rock fracture surface’s morphology characterization under different loading modes.


2011 ◽  
Vol 130-134 ◽  
pp. 2160-2165
Author(s):  
Hua Qiang ◽  
Rui Yang ◽  
Guo Dong Zhang

In this paper, in accordance with several common signal interference in sleep EEG detection, it is processed by wavelet transform. It mainly includes: ①.remove white noise from EEG using wavelet threshold method; ②.remove baseline drift from EEG using wavelet decomposition and reconstruction method; ③.remove sharp pulse interference using wavelet modulus maximum algorithm; ④.remove EMG from EEG using wavelet decomposition and reconstruction as well as modulus maximum method. The results of simulation study show that: it can filter a variety of common interference in EEG detection preferably by wavelet transform.


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