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11.
Tahar Boubellouta Romdhane Karoui Annick Lebecque Éric Dufour 《European Food Research and Technology》2010,231(6):873-882
Twelve samples of cheeses (three types of Saint-Nectaire PDO cheeses and Savaron cheeses) differing by manufacturing and ripening
conditions, from 12 different producers, were characterised by attenuated total reflectance mid-infrared (MIR) and front-face
fluorescence spectroscopies, dynamic testing rheology and physico-chemical analysis. Fluorescence spectra (tryptophan residues,
vitamin A and riboflavin) and MIR (3,000–2,800 (fat region), 1,700–1,500 (protein region) and 1,500–900 cm−1 (fingerprint region)) spectra were recorded on cheese samples. The potential of the data tables was investigated for discriminating
the four different groups of cheeses. The results of factorial discriminant analysis (FDA) performed on the fluorescence and
mid-infrared spectra showed a good discrimination of the four cheese groups. Considering cross-validation results, the best
classifications (100%) were achieved from mid-infrared and fluorescence spectra, while only 91.7 and 72.2% of correct classification
were obtained by applying FDA to rheology and physico-chemical data, respectively. Spectroscopic techniques could provide
useful fingerprints and allow the identification of investigated cheeses according to manufacturing conditions. Simple and
rapid spectroscopic methods offer a promising approach to the authentication of cheeses. 相似文献
12.
Amr?T.?Abdel-HamidEmail author Sofiéne?Tahar El?Mostapha?Aboulhamid 《Design Automation for Embedded Systems》2004,9(3):211-227
Intellectual property (IP) block reuse is essential for facilitating the design process of system-on-a-chip. Sharing IP designs poses significant high security risks. Recently, digital watermarking emerged as a candidate solution for copyright protection of IP blocks. In this paper, we survey and classify different techniques used for watermarking IP designs. To this end, we defined several evaluation criteria, which can also be used as a benchmark for new IP watermarking developments. Furthermore, we established a comprehensive set of requirements for future IP watermarking techniques. 相似文献
13.
Molka Attia Hili Tahar Fakhfakh Mohamed Haddar 《Journal of Engineering Mathematics》2007,57(4):351-363
Free vibrations of a spinning disk–shaft system are analysed using the finite-element method. The spinning disk is described
by the Kirchhoff plate theory. The shaft is modelled by a rotating beam. Using Lagrange’s principle and including the rigid-body
translation and tilting motion, equations of motion of the spinning flexible disk and shaft are derived consistently to satisfying
the geometric compatibility conditions on the internal boundaries among the substructures. The finite-element method is then
used to discretize the derived governing equations. The method is applied to the shaft–disk spinning system. The sensitivity
to the running speed as well as the effect of both disk flexibility and boundary condition on the natural frequencies of the
spinning system are numerically investigated. 相似文献
14.
L. Ben Tahar M. Artus F. Herbst S. Ammar F. Fiévet 《Materials Research Bulletin》2007,42(11):1888-1896
Pure nanoparticles of the CoFe2−xRExO4 (RE = Gd, Sm; x = 0.0, 0.1) system have been prepared by forced hydrolysis in polyol. The insertion of Sm3+ and Gd3+ cations into the cobalt ferrite structure has been investigated. X-ray micro-analysis (EDX) shows that the RE contents are close to the nominal ones. X-ray diffraction (XRD) evidences a cell size increase with slight distortions in the spinel-like lattice indicating the entrance of RE3+ ions. Micro-Raman spectroscopy confirms the cubic inverse-spinel structure and rules out the existence of impurities like hematite. Magnetic measurements (SQUID) show important differences in the magnetic properties of the unsubstituted and substituted particles. All the particles are superparamagnetic at room temperature and ferrimagnetic at low temperature. However, their main magnetic characteristics appear to be directly dependent on the RE content. 相似文献
15.
Markov chains are extensively used in modeling different aspects of engineering and scientific systems, such as performance of algorithms and reliability of systems. Different techniques have been developed for analyzing Markovian models, for example, Markov Chain Monte Carlo based simulation, Markov Analyzer, and more recently probabilistic model-checking. However, these techniques either do not guarantee accurate analysis or are not scalable. Higher-order-logic theorem proving is a formal method that has the ability to overcome the above mentioned limitations. However, it is not mature enough to handle all sorts of Markovian models. In this paper, we propose a formalization of Discrete-Time Markov Chain (DTMC) that facilitates formal reasoning about time-homogeneous finite-state discrete-time Markov chain. In particular, we provide a formal verification on some of its important properties, such as joint probabilities, Chapman-Kolmogorov equation, reversibility property, using higher-order logic. To demonstrate the usefulness of our work, we analyze two applications: a simplified binary communication channel and the Automatic Mail Quality Measurement protocol. 相似文献
16.
A comparative evaluation of filter-based feature selection methods for hyper-spectral band selection
Bo Wu Chongcheng Chen Tahar Mohand Kechadi Liya Sun 《International journal of remote sensing》2013,34(22):7974-7990
Band selection (dimensionality reduction) plays an essential role in hyper-spectral image processing and applications. This article presents a unified comparison framework for systematic performance comparison of filter-based feature selection models and conducts a comparative evaluation of four methods: maximal minimal associated index (MMAIQ), mutual information-based max-dependency criterion (mRMR), relief feature selection (Relief-F), and correlation-based feature selection (CFS) for hyper-spectral band selection. The evaluation is based on the performance of effectiveness, robustness, and classification accuracy, which involves five measuring indices: class separability, feature entropy, feature stability, feature redundancy, and classification accuracy. Three images acquired by different sensors were used to investigate the performance of the metrics. Experimental results show the best results for MMAIQ for all data sets in terms of used measurements, except for feature stability where mRMR and Relief-F exhibit their superiority. 相似文献
17.
Rim Khlifi Sami Sayadi Lassaad Belbahri Steve Woodward Tahar Mechichi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(12):1828-1833
BACKGROUND: This study concerns the assessment of laccase stability during textile industry effluent treatment by laccase in the presence of a mediator RESULTS: The effects of 1‐hydroxybenzotriazole (HBT) and textile wastewater on the stability of a crude laccase prepared from cultures of Trametes trogii during the process of textile industry effluent decolourization were determined. HBT was essential for decolourization of effluent by laccase. Decolourization efficiency decreased when effluent was repeatedly added to the reaction mixture, suggesting inhibition of laccase during the process. Stability of the laccase was not affected by different concentrations of effluent, but inactivation was proportional to HBT concentration. CONCLUSION: Experimental results showed that a redox mediator such as HBT was required for high decolourization rate of textile industry effluent; however free radicals generated from this compound inactivated the laccase used in the process. Copyright © 2009 Society of Chemical Industry 相似文献
18.
Photodegradation of phenol red in the presence of oxyhydroxide of Fe(III) (Goethite) under artificial and a natural light
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Sara Belattar Nadra Debbache Imen Ghoul Tahar Sehili Ala Abdessemed 《Water and Environment Journal》2018,32(3):358-365
The (α‐FeOOH) Goethite composite is a stable and an efficient catalyst in aqueous suspension under irradiation at 365 nm and by solar light. The photocatalytic activities of this composite were evaluated using Phenol Red (PR) dye (phenolsulfonphthalein class). In the dark, controlling factors, such as the pH and the adsorption of PR on Goethite surface were evaluated (before starting the photochemical experiments). It was found that the system PR‐Goethite present a small decrease in the main band of the dye (435 nm) which was explained by the low rate of adsorption of this dye on the Goethite. Also, we note that 40% of PR decolourisation was obtained after 200 min by the system PR‐Goethite‐hydrogen peroxide (H2O2) in dark due to the formation of ?OH by thermal decomposition of H2O2 on the surface of Goethite. The effects of various experimental parameters, such as initial dye concentration, pH, photocatalyst amount, tert‐Butyl alcohol effect and H2O2 addition were investigated in the study of photodegradation of the dye. The results showed that the photodegradation of PR under UV‐A (365 nm) irradiation could be enhanced greatly in the presence of H2O2. Natural radiation tests (under sunlight) showed that degradation was faster comparing with that obtained using the artificial one at 365 nm. Studies of the mineralization using total organic carbon method under naturel light certify that this method, compatible with the environment, may be considered in the treatment of wastewater and generally in the process of removal of this kind of pollutant. 相似文献
19.
Today’s analog/RF design and verification face significant challenges due to circuit complexity, process variations and short
market windows. In particular, the influence of technology parameters on circuits, and the issues related to noise modeling
and verification still remain a priority for many applications. Noise could be due to unwanted interaction between the circuit
elements or it could be inherited from the circuit elements. In addition, manufacturing disparity influence the characteristic
behavior of the manufactured circuits. In this paper, we propose a methodology for modeling and verification of analog/RF
designs in the presence of noise and process variations. Our approach is based on modeling the designs using stochastic differential
equations (SDE) that will allow us to incorporate the statistical nature of noise. We also integrate the device variation
due to 0.18μ
m fabrication process in an SDE based simulation framework for monitoring properties of interest in order to quickly detect
errors. Our approach is illustrated on nonlinear Tunnel-Diode and a Colpitts oscillator circuits. 相似文献
20.
In the treatment of cancerous tumors, the thermal dose is the time temperature history required to treat or destroy the undesirable tissue. The aim of this article is to calculate the optimum history of the heat source that, in the one-dimensional bioheat transfer model, results in the desired thermal dose. The time dependent strength of this source defines the accumulated energy at the end of a single heat treatment period. First the optimum control problem is formulated in infinite-dimensional form. The associated adjoint problem is obtained using the calculus of variations and an analytical formula is derived for the gradient of the functional of interest. Then a parametric representation of the control parameter is developed and the adjoint state approach is performed in conjugation with the conjugate gradient method for the solution of this control problem in finite-dimensional form. A one-dimensional numerical case is analyzed and discussed to demonstrate the performance and the robustness of the present method. 相似文献