Time‐frequency energy distribution analysis of a shallow water acoustics experiment at the AGS site

1994 ◽  
Vol 95 (5) ◽  
pp. 2928-2928 ◽  
Author(s):  
Indra Jaya ◽  
Mohsen Badiey ◽  
Alexander Cheng ◽  
Mark Pulaski
Keyword(s):  
Energy Distribution ◽  
Shallow Water ◽  
Distribution Analysis ◽  
Shallow Water Acoustics ◽  
Time Frequency

Copula-Based Time-Frequency Distribution Analysis for Planetary Gearbox Fault Detection

2017 ◽  
Author(s):  
Libin Liu ◽  
Ming J. Zuo
Keyword(s):  
Fault Detection ◽  
Energy Distribution ◽  
Simulated Data ◽  
Frequency Resolution ◽  
Data Sets ◽  
Distribution Analysis ◽  
Frequency Distributions ◽  
Copula Theory ◽  
Planetary Gearbox ◽  
Time Frequency

Linear and bilinear time-frequency distributions (TFDs) have been employed in planetary gearbox fault diagnosis. For linear TFDs, there is a trade-off between the time localization and frequency resolution and the spectrogram may not have correct energy marginals. For bilinear TFDs, they cannot be interpreted as an energy distribution because of the existence of possible negative values even though they are designed for energy density representation. To overcome these shortcomings, TFDs based on copula theory have been reported in the literature. In this paper, we analyze two simulated data sets using linear TFD and copula-based TFD. The results show that the constructed copula-based TFD has desirable properties of being positive, free from cross-term interference, having high time-frequency resolution and matching well with true marginals. The copula-based TFD is also able to locate fault-induced impulses by vertical lines over a certain frequency range in the time-frequency domain. Consequently, this study confirms the advantages of the copula-based TFD as an energy distribution and its capability in fault detection for planetary gearboxes.

scholarly journals SPEAKER LOCALIZATION AND SPEECH SEPARATIONIN TWO ECHOIC MIXTURES / KALBĖTOJO APTIKIMAS IR ŠNEKOS IŠSKYRIMAS DVIEJŲ SIGNALŲ MIŠINIUOSE SU AIDU

2011 ◽  
Vol 3 (1) ◽  
pp. 43-49
Author(s):  
Włodzimierz Kasprzak ◽  
Ning Ding ◽  
Nozomu Hamada
Keyword(s):  
Energy Distribution ◽  
Estimation Error ◽  
Real Life ◽  
Low Frequency ◽  
Delay Estimation ◽  
Distribution Analysis ◽  
Time Frequency ◽  
Time Points ◽  
Fundamental Frequencies ◽  
Orientation Histogram

We are developing two crucial improvements on the time-frequency masking approach to the blind speech separation of underdetermined mixtures when processing anechoic and echoic mixtures. First, the proposed method copes with the usually large amount of delay estimation error that appears in a low frequency band. This step generates a restrictive mask for phase delays on the basis of local and global energy distribution analysis. This mask allows the selected cells to contribute to the orientation histogram. Second, the strong WDO assumption (disjoint orthogonal frequency domain) is relaxed by allowing some frequency bins to be shared by both sources. By detecting fundamental frequencies of speakers at instantaneous time points, mask creation is supported by exploring their harmonic frequencies. The proposed method is proved to be effective and reliable in conducting experiments with both simulated and real-life mixtures.

Hawaii Experimental Acoustics Range for Shallow Water Applications

2011 ◽  
Vol 45 (3) ◽  
pp. 69-76 ◽  
Author(s):  
Tom Fedenczuk ◽  
Eva-Marie Nosal
Keyword(s):  
Shallow Water ◽  
Water Environment ◽  
Shallow Water Acoustics ◽  
Central Node ◽  
Long Baseline ◽  
Wide Range ◽  
Shallow Water Environment ◽  
Near Shore ◽  
Monitoring And Surveillance ◽  
Passive Acoustic

AbstractShallow water acoustics provide a means for monitoring and surveillance of near-shore environments. This paper describes the current and future capabilities of the low- to high-frequency Hawaii Experimental Acoustics Range (HEAR) that was designed to facilitate a wide range of different shallow water acoustics experiments and allow researchers from various institutions to test various array components and configurations. HEAR is a portable facility that consists of multiple hydrophones (12‐16) cabled independently to a common central node. The design allows for variable array configurations and deployments in three modes: experimental (off boats and piers), autonomous, and cabled. An application of HEAR is illustrated by the results from a deployment at Makai Research Pier, Oahu, Hawaii. In this deployment, HEAR was configured as a long-baseline range of two volumetric subarrays to study passive acoustic tracking capabilities in a shallow water environment.

Adsorption of levofloxacin onto mechanochemistry treated zeolite: Modeling and site energy distribution analysis

2019 ◽  
Vol 222 ◽  
pp. 30-34 ◽  
Author(s):  
Zhen Chen ◽  
Wei Ma ◽  
Guang Lu ◽  
Fanqing Meng ◽  
Shibo Duan ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Distribution Analysis ◽  
Site Energy

Simulation Study of Damage Identification Method Based on Lamb Wave Scattering in Aluminium Plate

2012 ◽  
Vol 433-440 ◽  
pp. 2611-2618
Author(s):  
Zhen Hua Tian ◽  
Hong Yuan Li ◽  
Hong Xu
Keyword(s):  
Energy Distribution ◽  
Lamb Wave ◽  
Damage Identification ◽  
Optimization Method ◽  
Propagation Path ◽  
Transient Dynamic Analysis ◽  
Time Frequency ◽  
Damage Location ◽  
Identification Method ◽  
Short Time

The propagation of scattering Lamb wave in plate was simulated using transient dynamic analysis in ANSYS. In order to extract the characteristic information of received signal for damage identification, the short time Fourier transform based on time-frequency analysis was utilized, and then the energy distribution and envelop of received signal were obtained. Based on the displacement contour of simulation and energy distribution, the propagation of scattering wave in plate with a through hole was examined. Also, a mathematic relationship between damage location and scattering signal was developed, with the help of wave propagation path through actuator, damage and sensor. A nonlinear optimization method was applied on the mathematic relationship to obtain the damage location. The damage identification method using scattering Lamb wave was therefore established.

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