Radiation from non uniformly moving sources in the plasma

2004 ◽  
Author(s):  
V.S. Rabinovich ◽  
I.M. Sancez
Keyword(s):  
Moving Sources

Separating Multiple Moving Sources by Microphone Array Signals for Wayside Acoustic Fault Diagnosis

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Wei Xiong ◽  
Qingbo He ◽  
Zhike Peng
Keyword(s):  
Fault Diagnosis ◽  
Time Domain ◽  
Feature Matching ◽  
Matching Pursuit ◽  
Microphone Array ◽  
Time Frequency ◽  
Moving Sources ◽  
The Time Domain ◽  
Envelope Spectrum ◽  
Threshold Setting

Wayside acoustic defective bearing detector (ADBD) system is a potential technique in ensuring the safety of traveling vehicles. However, Doppler distortion and multiple moving sources aliasing in the acquired acoustic signals decrease the accuracy of defective bearing fault diagnosis. Currently, the method of constructing time-frequency (TF) masks for source separation was limited by an empirical threshold setting. To overcome this limitation, this study proposed a dynamic Doppler multisource separation model and constructed a time domain-separating matrix (TDSM) to realize multiple moving sources separation in the time domain. The TDSM was designed with two steps of (1) constructing separating curves and time domain remapping matrix (TDRM) and (2) remapping each element of separating curves to its corresponding time according to the TDRM. Both TDSM and TDRM were driven by geometrical and motion parameters, which would be estimated by Doppler feature matching pursuit (DFMP) algorithm. After gaining the source components from the observed signals, correlation operation was carried out to estimate source signals. Moreover, fault diagnosis could be carried out by envelope spectrum analysis. Compared with the method of constructing TF masks, the proposed strategy could avoid setting thresholds empirically. Finally, the effectiveness of the proposed technique was validated by simulation and experimental cases. Results indicated the potential of this method for improving the performance of the ADBD system.

scholarly journals Electromagnetic fields produced by moving sources in a curved beam pipe

2009 ◽  
Vol 50 (6) ◽  
pp. 063510 ◽  
Author(s):  
Shin-itiro Goto ◽  
Robin W Tucker
Keyword(s):  
Electromagnetic Fields ◽  
Curved Beam ◽  
Moving Sources ◽  
Beam Pipe

Diffraction of sound due to moving sources by barriers and ground discontinuities

2006 ◽  
Vol 120 (3) ◽  
pp. 1274-1283 ◽  
Author(s):  
M. Buret ◽  
K. M. Li ◽  
K. Attenborough
Keyword(s):  
Moving Sources
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