Song Gao^1,*, Xin Jin¹, Qiaohong Liu²

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 511-529, 2021, DOI:10.32604/fdmp.2021.012741

Abstract The signals generated by electromagnetic flow sensors used for slurry fluids are often affected by noise interference produced by interaction with the slurry itself. In this study, the power spectrum characteristics of the signal are studied, and an attempt is made to determine the relationship between the characteristics of the related noise and the velocity and concentration of the slurry fluid. Dedicated experiments are conducted and the related power spectrum curve is obtained processing the signal measured by the sensor with Matlab. Numerical simulations are also carried out in the frame of an Eulerian approach in order get additional insights… More >

Dah-Jing Jwo^1,*, Wei-Yeh Chang¹, I-Hua Wu²

CMC-Computers, Materials & Continua, Vol.67, No.3, pp. 3983-4003, 2021, DOI:10.32604/cmc.2021.014752

Abstract This paper revisits the characteristics of windowing techniques with various window functions involved, and successively investigates spectral leakage mitigation utilizing the Welch method. The discrete Fourier transform (DFT) is ubiquitous in digital signal processing (DSP) for the spectrum analysis and can be efficiently realized by the fast Fourier transform (FFT). The sampling signal will result in distortion and thus may cause unpredictable spectral leakage in discrete spectrum when the DFT is employed. Windowing is implemented by multiplying the input signal with a window function and windowing amplitude modulates the input signal so that the spectral leakage is evened out. Therefore,… More >

Brian Schwarz, Patrick McHargue, Mark Richardson

Sound & Vibration, Vol.52, No.2, pp. 1-6, 2018, DOI:10.32604/sv.2018.03637

Abstract In this paper, we show how Operating Deflection Shapes (ODS’s) and mode shapes can be obtained experimentally from measurements that are made using only two sensors and two short wires to connect them to a multi-channel acquisition system. This new test procedure is depicted in Figure 1. Not only is the equipment required to do a test much more cost effective, but this method can be used to test any sized test article, especially large ones.
The testing method introduced here involves moving a pair of sensors along together in a prescribed manor, and calculating the Transmissibility between them. The… More >

Xiaoying Chen^{1, 2, *}, Shijun Zhao², Xiaolei Wang², Xuejin Sun², Jing Feng², Nan Ye³

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 861-875, 2019, DOI:10.32604/cmc.2019.06230

Abstract It is important to extract texture feature from the ground-base cloud image for cloud type automatic detection. In this paper, a new method is presented to capture the contour edge, texture and geometric structure of cloud images by using Contourlet and the power spectrum analysis algorithm. More abundant texture information is extracted. Cloud images can be obtained a multiscale and multidirection decomposition. The coefficient matrix from Contourlet transform of ground nephogram is calculated. The energy, mean and variance characteristics calculated from coefficient matrix are composed of the feature information. The frequency information of the data series from the feature vector… More >