Tatouage audio par EMD

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

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

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

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

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

Markov property of the solution of the stochastic generalized equations

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

Codage des signaux par EMD

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

Impact of the food safety policies on the reduction of poverty in Tunisian rural areas

The observed trend of decreasing poverty in Tunisian rural areas, where agriculture is still dominated by family and where illiteracy rate and family size are high, questions may be raised about the economic policies adopted by the state. This article puts the analyses of these policies in the framework of food safety issue as food and poverty are tightly related and as food safety objective is multi-sectorial and multi-disciplinary. In economic development plans, food safety objective took the place of self-sufficiency. The analysis of food safety policy is based on a macro-economic analysis of the offer (policies of production pricing and subsidizing, investment policies) and demand (Policies of consumption subsidies and consumer prices) as well as the policies of fight against poverty. This analysis covers two periods: before and after the economic reforms of privatization and liberalization of 1987 (PAS: Structural Adjustment Plan). The assessment of these policies shows that poverty fighting programs are numerous and rich in experiences. These policies are more and more based on assistance programs oriented toward productive actions. The liberalization and privatization efforts were reflected by better performance and competitiveness of the agricultural sector. This had a positive impact on the employment, the migration and the availability of food products in rural areas. The self targeting of the subsidies by differentiating the products reduced the budgetary cost of these transfers and enhanced the equity and the nutritional and food situation of the poor people. The higher increase in income of country people and the decrease of subsidies indicate the more and more use of income direct transfers.Poverty, rural area, structure adjustment, food safety, agricultural and food policies., Food Consumption/Nutrition/Food Safety, Food Security and Poverty,

Impact of location and forestry conditions on some physical and mechanical properties of northern Tunisian Pinus pinea L. wood

Pinea pines have been used and cultivated for their edible pine nuts since prehistoric times. More recently, Pinus pinea L. has been introduced as an ornamental tree in Mediterranean regions, and is now often found in city parks and gardens. However, it has become naturalized outside North African cities to the point that it is now classified as an invasive species there. Its size (more than 15-20 m in height and 30- 40 cm in diameter) makes Pinus pinea a good candidate eco-resource for construction materials in Tunisia. The focus of this study was to analyze the effects of geographical location and forestry conditions on several physical and mechanical properties of Northern Tunisian Pinea pine wood. The Pinus pinea wood samples studied were collected from four different geographical locations, divided into 87 plots according to tree population density and soil fertility class. Density, shrinkage and moisture content were measured and mechanical tests were performed on each wood sample. Preliminary results showed that Tunisian Pinea pine wood has very good dimensional stability in relation to its density. However, the modulus of rupture (MOR) in bending and compression strength is lower than in other Tunisian softwood species, whatever the geographical situation and soil fertility. A linear regression analysis showed that only tree population density seems to have a significant impact on the variability of Pinea wood properties, except for dimensional stability and volumetric shrinkage. Our findings suggest that the growing population density of P. pinea trees is the most important forestry parameter determining its mechanical and physical wood material properties. It could therefore be of interest to improve forestry conditions to obtain better wood quality. (Résumé d'auteur