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Advanced spectral analysis and cross correlation based on the empirical mode decomposition: application to the environmental time series ArchiMer
Ben Ismail, Dhouha Kbaier; Lazure, Pascal; Puillat, Ingrid.
Abstract—In marine sciences, time series are often nonlinear and nonstationary. Adequate and specific methods are needed to analyze such series. In this paper, an application of the Empirical Mode Decomposition method (EMD) associated to the Hilbert Spectral Analysis (HSA) is presented. Furthermore, EMD based Time Dependent Intrinsic Correlation (TDIC) analysis is applied to consider the correlation between two nonstationary time series. Four temperature time series obtained from automatic measurements in nearshore waters of the Réunion island are considered, recorded every ten minutes from July 2011 to January 2012. The application of the EMD on these series and the estimation of their power spectra using the HSA are illustrated. The authors identify...
Tipo: Text Palavras-chave: Augmented Dickey-Fuller tests; Cross correlation; Empirical mode decomposition (EMD); Hilbert spectral analysis (HSA); Hilbert-Huang transform (HHT); Stationarity; Time-dependent intrinsic correlation (TDIC); Time series; Wavelets.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00270/38077/36205.pdf
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Application of Hilbert-Huang decomposition to temperature and currents data in the Réunion island ArchiMer
Kbaier-ben Ismail, Dhouha; Lazure, Pascal; Puillat Felix, Ingrid.
In marine sciences, time series are often nonlinear and nonstationary. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. We use the Hilbert-Huang Transform (HHT) for the spectral analysis of high frequency sampled time series in near shore waters of the Réunion island, located in the Indian Ocean 700 km east of Madagascar. We focus particularly on automatic measurements of sea level fluctuations, temperature records and current data sets at four different stations in the island. We look at the contribution of different Intrinsic Mode Functions (IMFs) obtained by the Empirical Mode Decomposition (EMD) and also compare the Hilbert spectra with the wavelet spectra. The inertial wave and several...
Tipo: Text Palavras-chave: Cross correlation; Empirical mode decomposition (EMD); Hilbert spectral analysis (HSA); Hilbert-Huang transform (HHT); Stationarity; Time-dependent intrinsic correlation (TDIC); Time series; Wavelets.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00383/49392/49822.pdf
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Implications de la couleur du bruit environnemental sur la variabilité des stocks halieutiques exploités ArchiMer
Rouyer, Tristan.
The origin of fish stocks variability is a key question in fisheries science. The exploitation indeed has an important effect in terms of biomass reduction, but environmental forcing is of central interest as it affects numerous key biological processes. Recent theoretical results have shown that the nature of the environmental fluctuations, the environmental noise, has important ecological consequences on populations and particularly on their fluctuations. In addition the effects of exploitation, that are not a simple removal of individuals but also profoundly modifies the demography, the structure and the trophic interactions of fish stocks, can interact with environmental effects. Through an extensive analysis of time series we aim at understanding the...
Tipo: Text Palavras-chave: Fisheries; Life history traits; Fish stocks variability; Environmental noise; Wavelets; Time series; Pêche; Traits d'histoire de vie; Variabilité des stocks halieutiques; Couleur du bruit environnemental; Ondelettes; Séries temporelles.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/these-6596.pdf
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Sistema computacional para auxílio ao diagnóstico em exames de tuberculose animal Arq. Bras. Med. Vet. Zootec.
Gracioso,A.C.N.R.; Souza Filho,R.A.M.; Gonzaga,A.; Fernandez,F.J.R..
The results obtained in evaluating the efficiency of a Neuro-Fuzzy System NEFCLASS (Neuro-Fuzzy Classification) in image classification of cattle tuberculosis, based on its texture features extracted using the wavelet transform are presented. For testing, images of animal tissues diagnosed with tuberculosis were used, as provided by the Tuberculosis Laboratory at the Instituto Biológico de São Paulo. The results of this study can serve as a basis for developing systems for diagnosis aimed at reducing human effort, by automating all or parts of the classification of images, helping lab technicians to sort amongst different pathologies.
Tipo: Info:eu-repo/semantics/article Palavras-chave: CBIR; Wavelets; Neuro-fuzzy; Tuberculosis.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352013000200045
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Statistical properties and time-frequency analysis of temperature, salinity and turbidity measured by the MAREL Carnot station in the coastal waters of Boulogne-sur-Mer (France) ArchiMer
Ben Ismail, Dhouha Kbaier; Lazure, Pascal; Puillat, Ingrid.
In marine sciences, many fields display high variability over a large range of spatial and temporal scales, from seconds to thus ousands of years. The longer and longer recorded time series, with an increasing sampling frequency, in this field are often nonlinear, nonstationary, multiscale and noisy. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. The objective of this paper is to highlight time series analysis methods already applied in econometrics, signal processing, health,etc. to the environmental marine domain, assess advantages and inconvenients and compare classical techniques with more recent ones. Temperature, turbidity and salinity are important quantities for ecosystem studies. The...
Tipo: Text Palavras-chave: Continuous wavelet transform; Cross-correlation; Empirical mode decomposition; Hilbert Huang Transform; Stationarity; Time dependent intrinsic correlation; Time series; Wavelets.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00324/43519/43050.pdf
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