Karoui A.,University of Carthage
Journal of the Franklin Institute | Year: 2011
In this work, we give a brief description of the theory and the properties of the 1-D and 2-D prolate spheroidal wave functions (PSWFs). Then, we study some efficient methods for the computation of the different PSWFs and their associated eigenvalues. More precisely, we shall develop a quadrature method for the approximation of the 1-D PSWFs. Then, we extend this method to the construction of the 2-D PSWFs that are concentrated on the unit disk. Also, we give a brief review of the quality of approximation of almost band-limited functions by the 1-D PSWFs. Moreover, we use some numerical tests to compare between PSWFs and wavelets as signal processing tools. In particular, we give some numerical tests that highlight the efficiency of the PSWFs in processing band-limited signals. © 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
Kaaniche M.-B.,University of Carthage |
Bremond F.,French Institute for Research in Computer Science and Automation
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2012
We introduce a new gesture recognition framework based on learning local motion signatures (LMSs) of HOG descriptors introduced by . Our main contribution is to propose a new probabilistic learning-classification scheme based on a reliable tracking of local features. After the generation of these LMSs computed on one individual by tracking Histograms of Oriented Gradient (HOG)  descriptor, we learn a codebook of video-words (i.e., clusters of LMSs) using k-means algorithm on a learning gesture video database. Then, the video-words are compacted to a code-book of codewords by the Maximization of Mutual Information (MMI) algorithm. At the final step, we compare the LMSs generated for a new gesture w.r.t. the learned code-book via the k-nearest neighbors (k-NN) algorithm and a novel voting strategy. Our main contribution is the handling of the N to N mapping between codewords and gesture labels within the proposed voting strategy. Experiments have been carried out on two public gesture databases: KTH  and IXMAS . Results show that the proposed method outperforms recent state-of-the-art methods. © 2012 IEEE.
Naghmouchi I.,University of Carthage
International Journal of Bifurcation and Chaos | Year: 2011
We show that, for monotone graph map f, all the ω-limit sets are finite whenever f has periodic point and for monotone dendrite map, any infinite ω-limit set does not contain periodic points. As a consequence, monotone graph and dendrite maps have no LiYorke pairs. However, we built a homeomorphism on a dendroid with a scrambled set having nonempty interior. © 2011 World Scientific Publishing Company.
Jammazi C.,University of Carthage
IMA Journal of Mathematical Control and Information | Year: 2010
The article gives Lyapunov-type sufficient conditions for partial finite-time and asymptotic stability in which some state variables converge to zero, while the rest converge to constant values that possibly depend on the initial conditions. The article then presents partially asymptotically stabilizing controllers for many non-linear control systems for which continuous asymptotically stabilizing (in the usual sense) controllers are known not to exist.
Chouchani C.,University of Carthage
Canadian journal of microbiology | Year: 2012
The spread of multidrug-resistant strains of Klebsiella pneumoniae in hospitals is of concern to clinical microbiologists, health care professionals, and physicians because of the impact infections caused by these bacteria have in causing morbidity and mortality. Clinical isolates of K. pneumoniae have been found to show resistance to third-generation cephalosporins as a result of acquiring extended-spectrum β-lactamase-producing genes, such as bla(CTX-M). Since little is known about the mechanisms of antibiotic resistance observed in Kasserine hospital, Tunisia, this study was undertaken to investigate the mechanisms by which clinical isolates of K. pneumoniae resist β-lactam antibiotics. Twelve strains of K. pneumoniae were collected from patients admitted to Kasserine hospital; these isolates showed multiresistance phenotypes. Molecular genetics investigations using polymerase chain reaction, S1 digestion, and pulsed-field gel electrophoresisshowed that bla(CTX-M-15) in association with ISEcp1 is responsible for the resistance of these strains to third-generation cephalosporins. It has been determined that bla(CTX-M-15) is chromosomally mediated and plasmid mediated, which alarming need for infection control to prevent the outbreak of such a resistance mechanism.