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L’imagerie médicale: du 2D au 3D, les problèmes particuliers posés par la reconstruction tomographique en tomographie par émission de positons
1917: Radon shows that a function can, be recontructed from its projections. For 60 years, the implementation of this theory to analogue data is a...
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Fiber optic applications of multiple quantum well electroabsorption modulators
Electroabsorption modulators ( eam ) have proved to be very attractive both as optical sources (monolithically integrated NRZ transmitters and rz pulse...
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Potentialités des séquences d’étalement chaotiques pour l’amélioration duTEEB d’un systèmeDS-CDMA asynchrone
The use of chaotic sequences as spectral spreading sequences in a Direct Sequence-Code Division Multiple Access is proposed in this paper. The...
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Multimedia forward error correcting codes for wirelessLAN
In this paper the forward error correction ( FEC ) codes useful for multimedia wireless transmissions are discussed. The class of usable codes are...
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Analyse des performances d’un système de transmission de séquences vidéo comprimées H.263 et turbo-codées sur un lien umts/tdd descendant
The aim of this paper is to present a comparative study of the performances, in terms of the mean psnr (Peak Signal to Noise Ratio), of a umts/tdd...
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Vers les 20 kbit/s en transmission décamétrique ionosphérique : une application du traitement d’antenne sur des capteurs colocalisés
This paper presents an operational system of digital transmission within the h.f. frequency range, aiming at a significant increase of the data...
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3D Scan-Based Wavelet Transform and Quality Control for Video Coding
Wavelet coding has been shown to achieve better compression than DCT coding and moreover allows scalability. 2D DWT can be easily extended to 3D and...
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Du Minitel à l’Internet: perception du risque et transition chez les internautes utilisateurs des services bancaires
Based on media richness theory and on the technology acceptance model, this article shows that, in general, Internet is perceived as superior to the...
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Les outils du commerce électronique
Electronic commerce ( ec ) is a combination of practices, strategies, processes, applications and technologies, enabling business transactions. This...
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Nouvelle utilisation de l’information spatiale pour l’indexation d’images basée contenu
Most indexing systems are based on global image descriptors. Nowadays, new representations are used. They try to describe images more precisely...
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Application level framing applied to image compression
Two well-known wavelet zerotree encoding algorithms, Embedded Zerotree Encoding ( Ezw ) and Set Partitioning in Hierarchical Trees ( Spiht ), provide...
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Traitement itératif conjoint pour les systèmes mobiles sans fil
The classical receiver performs separately three tasks, namely, channel estimation , equalization and decoding. The optimal receiver however would...
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Tracking of Objects in Video Scenes with Time Varying Content
We propose a method for tracking of objects contained in video sequences. Each video object is represented by a set of polygonal regions. A bottom up...
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Maximuma posteriori semi-blind channel estimation for ofdm systems operating on highly frequency and time selective channels
We propose a semi-blind block-by-block channel estimation algorithm for ofdm systems operating in highly frequency and time selective channels. This...
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La compression d’images embarquée pour les missions spatiales
On-board space instruments produce more and more high amount of data due to the increase in both resolution and number of bits per pixel, not...
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Compression de données brutes et d’images de radar à synthèse d’ouverture
This paper draws a state of the art of synthetic aperture radar (sar) data compression. Both raw data and synthesized image compression have been...
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Décodage par le treillis de codes polynomiaux: un écueil à éviter
We give a simple proof of a well known property of the maximum likelihood decoding of polynomial block codes: the systematic version of the code...
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A generalized framework for iterative source-channel decoding
Joint source-channel decoding is considered for a transmission system, in which the quantizer indices of several autocorrelated source signals are...