scholarly journals Dolphins Underwater Sounds Database: Preliminary Analysis Results

TEM Journal ◽  
2020 ◽  
pp. 1426-1434
Author(s):  
Hristo Zhivomirov ◽  
Ivaylo Nedelchev

The present paper treats the signal recording and the preliminary analysis of the vocalization of five Caribbean bottlenose dolphins (Tursiops Truncates) in the controlled aquatic environment – a dolphinarium water pool. The data are taken using measurement equipment from the world's leading companies – Brüel&Kjær and National Instruments Corporation. All records have been denoised and segmented in advance so that only the vocal-active parts to be analyzed. The most representative part of the records and analysis results are deposited in one of world's most reputable databases – IEEE DataPort™, under the name "Dolphins Underwater Sounds Database". All analyses are conducted in the Matlab environment, thus they include: signal oscillogram, overall frequency spectrum, time-frequency spectrogram, time-quefrency cepstrogram and also signal correlogram and amplitude histogram. The report is rich in figures that represent some of the most interesting results. Finally, some common conclusions are drawn, based on the analysis results, and along with considerations for feature work.

2018 ◽  
Vol 44 (3) ◽  
pp. 256-266 ◽  
Author(s):  
Don R. Bergfelt ◽  
John Lippolis ◽  
Michel Vandenplas ◽  
Sydney Davis ◽  
Blake A. Miller ◽  
...  

2012 ◽  
Vol 518-523 ◽  
pp. 3847-3851
Author(s):  
Mei Jun Zhang ◽  
Chuang Wang ◽  
Hao Chen ◽  
Qun Zhang Tu

In order to solve the endpoint effect and modal aliasing phenomenon in EMD and EEMD,Improved EEMD is put forward, and the application in signal singularity detection is researched in this paper. The improved EEMD will signal drops down into a series of different IMF to highlight the different local characteristics of original data, and then calculate Hilbert marginal spectrum and time-frequency spectrum to determine the frequency of these mutations and mutations position. To compared with FT, STFT, WVD,WT, EMD and EEMD etc, No cross-terms and no false IMF components are produced in the Hilbert time-frequency spectrum of the improved EEMD. Different frequency components and frequency mutations position are clearly distinguished at the same time. The Hilbert time-frequency spectrum of the improved EEMD has more superior detection signal singularity ability.


Author(s):  
Z. Cherneva ◽  
C. Guedes Soares

The main goal of the present paper is to study the differences of the descriptors of the wave groups in the nonlinear case in comparison with the same parameters for a Gaussian process. The data analyzed are from a deep water basin of Marintek. They consist of sequence of five identical independent experimental runs of unidirectional waves measured at ten fixed points situated in different distances from the wave maker. Each series contain about 1800 waves. Thus the statistics collected from a given gauge comprise about 9000 waves combined in a number of wave groups. Because the series describe a process significantly different from the Gaussian one, an upper and lower envelopes are introduced as lines which connect the peaks of the crests and the lower points of the troughs respectively. Spline functions are applied to calculate these envelopes. Then, the mean high run and mean group length are estimated for different levels, their ensemble average over five experimental runs is found for every gauge and is compared with the results of the theory of Gaussian process. It is found that the values of the mean time intervals of the groups correlate with coefficient of kurtosis of the process. It is determined also that mean group length is shorter and the mean high run is larger for the nonlinear wave groups in comparison with the Gaussian wave groups. The modification of wave groups in space and time is investigated in the work as well. Wigner time-frequency spectrum with Choi-Williams kernel is applied to describe the process of entire modulation and demodulation of the groups. It is found that before formation of the high wave a wave down-shifting takes place. At this stage the local spectrum is relatively narrow and the group shrinks continuously. Close to the focus the time-frequency spectrum is very wide and the group has a triangle form. Further the high wave breaks and the wave group acquires the form of “three sisters.” The transform of the group continues by its disintegration, the local spectrum stands narrow and an up-shifting is observed.


2014 ◽  
Vol 333 (17) ◽  
pp. 3889-3903 ◽  
Author(s):  
Shuaiyong Li ◽  
Yumei Wen ◽  
Ping Li ◽  
Jin Yang ◽  
Xiaoxuan Dong ◽  
...  

Geophysics ◽  
2007 ◽  
Vol 72 (1) ◽  
pp. V13-V20 ◽  
Author(s):  
Yanghua Wang

A seismic trace may be decomposed into a series of wavelets that match their time-frequency signature by using a matching pursuit algorithm, an iterative procedure of wavelet selection among a large and redundant dictionary. For reflection seismic signals, the Morlet wavelet may be employed, because it can represent quantitatively the energy attenuation and velocity dispersion of acoustic waves propagating through porous media. The efficiency of an adaptive wavelet selection is improved by making first a preliminary estimate and then a localized refining search, whereas complex-trace attributes and derived analytical expressions are also used in various stages. For a constituent wavelet, the scale is an important adaptive parameter that controls the width of wavelet in time and the bandwidth of the frequency spectrum. After matching pursuit decomposition, deleting wavelets with either very small or very large scale values can suppress spikes and sinusoid functions effectively from the time-frequency spectrum. This time-frequency spectrum may be used in turn for lithological analysis—for instance, detection of a gas reservoir. Investigation shows that the low-frequency shadow associated with a carbonate gas reservoir still exists, even high-frequency amplitudes are compensated by inverse-[Formula: see text] filtering.


2017 ◽  
Vol 14 (2) ◽  
pp. 236-246 ◽  
Author(s):  
De-Ying Wang ◽  
Jian-Ping Huang ◽  
Xue Kong ◽  
Zhen-Chun Li ◽  
Jiao Wang

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