1,931 research outputs found

    Tatouage audio par EMD

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    In this paper a new adaptive audio watermarking algorithm based on Empirical Mode Decomposition (EMD) is introduced. The audio signal is divided into frames and each one is decomposed adaptively, by EMD, into intrinsic oscillatory components called Intrinsic Mode Functions (IMFs). The watermark and the synchronization codes are embedded into the extrema of the last IMF, a low frequency mode stable under different attacks and preserving audio perceptual quality of the host signal. The data embedding rate of the proposed algorithm is 46.9–50.3 b/s. Relying on exhaustive simulations, we show the robustness of the hidden watermark for additive noise, MP3 compression, re-quantization, filtering, cropping and resampling. The comparison analysis shows that our method has better performance than watermarking schemes reported recently

    Codage des signaux par EMD

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    In this letter a new signals coding framework based on the Empirical Mode Decomposition (EMD) is introduced. The EMD breaks down any signal into a reduced number of oscillating components called Intrinsic Modes Decomposition (IMFs). Based on IMF properties, different coding strategies are presented. No assumptions concerning the linearity or the stationarity are made about the signal to be coded. Results obtained on ECG signals are presented and compared to those of wavelets coding

    An active contour for range image segmentation

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    In this paper a new classification of range image segmentation method is proposed according to the criterion of homogeneity which obeys the segmentation, then, a deformable model-type active contour 201C;Snake201D; is applied to segment range images

    L'ELEVAGE OVIN EXTENSIF EN TUNISIE : DISPONIBILITES ALIMENTAIRES ET INNOVATIONS POUR LA VALORISATION DES RESSOURCES FOURRAGERES LOCALES

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    N° ISBN - 978-2-7380-1284-5International audienceSheep farming plays a vital role in food safety in Tunisia. This paper aims to reflect the current status of sheep farming through an analysis of their food availability and limits. A study of the possibilities for improving the local feeding resources is then made identifying the innovations in this field. Results show that the decrease in pasture areas is caused by the over-grazing, the frequent droughts and the expansion of cereal crops and tree plantations. Use of concentrates becomes more frequent in livestock industry. These concentrates are heavily based on imported ingredients whose prices have tripled over the last two decades. Consequently, a renewed interest has been given to the use of local feed resources and looking for alternatives such as their partial or total replacement of the imported raw materials. The use of the local barley and field beans in the sheep feeding could ensure acceptable animal performances. In the arid and semi-arid Tunisian zones, thousands of hectares of fodder shrubs have been established, especially spineless cactus, Atriplex nummularia and Acacia cyanophylla. Other innovations in animal feeding demonstrated the effectiveness of alternative feed resources like using feed blocks which could represent a promising nutritional tool especially when animals are grazing on poor pastures, the use of multi-purpose shrubs, or several agricultural and agro-industrial by-products (treated straws, cakes, pulps...). A lack of adequate co-ordination and synergy between the different stakeholders is inhibiting the progress and implementation of transversal approaches that are necessary for the delivery of integrated sustainable policies

    Rehaussement du signal de parole par EMD et opérateur de Teager-Kaiser

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    The authors would like to thank Professor Mohamed Bahoura from Universite de Quebec a Rimouski for fruitful discussions on time adaptive thresholdingIn this paper a speech denoising strategy based on time adaptive thresholding of intrinsic modes functions (IMFs) of the signal, extracted by empirical mode decomposition (EMD), is introduced. The denoised signal is reconstructed by the superposition of its adaptive thresholded IMFs. Adaptive thresholds are estimated using the Teager–Kaiser energy operator (TKEO) of signal IMFs. More precisely, TKEO identifies the type of frame by expanding differences between speech and non-speech frames in each IMF. Based on the EMD, the proposed speech denoising scheme is a fully data-driven approach. The method is tested on speech signals with different noise levels and the results are compared to EMD-shrinkage and wavelet transform (WT) coupled with TKEO. Speech enhancement performance is evaluated using output signal to noise ratio (SNR) and perceptual evaluation of speech quality (PESQ) measure. Based on the analyzed speech signals, the proposed enhancement scheme performs better than WT-TKEO and EMD-shrinkage approaches in terms of output SNR and PESQ. The noise is greatly reduced using time-adaptive thresholding than universal thresholding. The study is limited to signals corrupted by additive white Gaussian noise

    Investigating Willingness to Communicate: The Case of EFL Learners at Tlemcen University, Algeria

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    This paper deals with EFL learners’ willingness to communicate (WTC). The main objective is find whether communication confidence and classroom environment affect learners’ willingness to enter into discourse in the classroom. A questionnaire was administered to twenty-one university students studying English at Tlemcen university, Algeria. The main results revealed that high levels of WTC are associated with both communication confidence and classroom environment. The paper also suggests some implications for EFL teachers. Keywords: willingness, communicate, EFL

    Markov property of the solution of the stochastic generalized equations

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    Some models of probabilities are described by generalized stochastic equations. These models (like that prediction) lead to the resolution of boundary problems for random distributions (generalized equations). We are interested in the equation Lx = f in S ⊂ IRd where L is a linear operator, f is a random distribution and to the class of boundary conditions on the frontier Γ = ∂S in order to define for the corresponding boundary conditions. The resolutions of boundary problems for random distributions lead to the Markov property for the solution of these equations. © 2007 Science Publication

    The Conceptualization and Development of the Social Self Image / Brand Image Construct: A Confirmatory Data Analysis Approach

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    This research paper reviews various conceptualizations and perspectives on the nature of the self image, brand image, and the social self congruity as presented in the previous literature. The aim of this paper is to propose a global and situation-free measure of the social self congruity construct. Confirmatory data analysis revealed that the proposed measure is highly reliable and demonstrates high levels of content, criterion, predictive, and convergent validity. Keywords: Self image, brand image, image congruence, confirmatory factor analysis, symbolic meaning, consumer behavior, social interaction
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