Correction de deux paquets d’erreurs par un code de Reed-Solomon

Algebraic decoding procedures can be greatly simplified in case the number of errors being corrected is small. The authors present here a decoder which is capable of correcting errors occuring on four bits packets. The considered code is a (15, 11) Reed-Solomon code over GF (16). A Meggitttype decoder has been selected. The hardware implementation consists of 49 ttl (ls) packages and operates for the present at a rate of 5 Mbit/s. The utilisation of this decoding scheme is considered for other Reed-Solomon codes.     

À propos de la conception de systèmes d’aide aux déplacements des déficients visuels

This paper aims to contribute to studies related to visual handicap in order to reduce/eliminate it with new technologies. It addresses shortly the main principle of 3D world human perception, the main rules for environmental pertinent data acquisition and their processing. The proposed state of art on blind people travel assisting aids (taa) allow to understand the requirements for new aids design. A few examples of research project show how solution from new information technologies (such as artificial vision, virtual reality, high densityvlsi, tactile systems, GPS, wireless networks, etc) can be integrated in new systems. These examples allow also to determine which concepts should be targeted when designing any new travel assistance for blind people autonomous and safe displacement, and to characterise new devices.     

Méthode originale d’analyse du diagramme de diffraction en puissance d’une cible radar en vue de la reconnaissance des formes

Aircraft modeling is often accomplished by replacing the skin of the aircraft by several conveniently placed scatterers. We show that a Radar Cross Section (rcs)diagram can be described as a sum of bipoint s diagrams and that this decomposition can be greatly simplified. Then we consider the extraction of bipoints parameters from the knowledge of a diagram of radar cross section in the far field. This study exhibits that the bipoint function is a system of Chebyshev polynomials of the first or second kind. After a changement of variables,the bipoint function becomes then a A.M. function. By a Fourier analysis of transformed rcs,we can find the lengths between the points and the amplitudes. This study can be also extended to a multipoint in a line which radiates with spatial directivity.     

Modélisation d’un anneauSDH pour les besoins de la gestion de fautes

When an anomaly occurs in aSDH network, many notifications are emitted towards the supervision center. The emission of these notifications is the result of the signals treatment on the level of the objects describing the network. This document describes the modeling process of the behavior and the interaction between the objects intervening in the data processing of faults management. It gives a methodology ofSDH network model construction for the needs for faults situations diagnosis.     

Utilisation de la corrélation pondérée dans un processus de détection d’intrusions

Generally, an intruder must perform several actions, organized in an intrusion scenario, to achieve his or her malicious objectives. Actions are modeled by their pre and post conditions, which are a set of logical predicates or negations of predicates. Pre conditions of an action correspond to conditions the system’s state must satisfy to perform the action. Post conditions correspond to the effects of executing the action on the system’s state. When an intruder begins his intrusion, we can deduce, from the alerts generated byidss (Intrusion Detection Systems), several possible scenarios, by correlating attacks, that lead to multiple intrusion objectives. However, with no further analysis, we are not able to decide which are the most plausible ones among the possible scenarios. We propose in this paper to define an order over the possible scenarios by weighting the correlation relations between successive attacks composing the scenarios. These weights reflect to what level executing some actions are necessary to execute some action B. We will see that to be satisfactory, the comparison operator between two scenarios must satisfy some properties.     

Conception et réalisation d’un simulateur de canal hertzien

The paper presents the design and implementation of a line-of-sight (Los)microwave channel simulator. The basic principle is to reproduce channel transfer functions given by their amplitude and group delay characteristics by driving a linear transversal filter with precomputed data. The transfer functions can be either collected from measurements in the field or derived from any analytical modelling of the Los microwave channel. It is shown that a thirteen tap filter with a 70 MHz period leads to accurate realtime simulations of selective fading in a 50 MHz bandwidth. The control interface, microprocessorbased, allows an efficient and smooth use of the simulator. Finally,hardware problems and technological solutions related to the implementation are presented.     

Démarche de conception d’une plate-forme monopuce de réception de radiodiffusion numérique DRM

The newdrm standard for digital radio broadcast in theam band requires integrated devices for radio receivers at low cost and very low power. A chipset has been developed based on anarm9 dual-core architecture. This paper introduces the application itself, and then presents the development process followed to design such a chip covering the hardware/software partitioning, the architecture definition and all the validation issues. Therf part that partially drives the baseband is also briefly presented. The legal aspects are also investigated. Then as a conclusion, this paper presents the next steps of this development and the methodological gap in the system on chip design process.     

L’apprentissage des modes de vie: une base indispensable au développement d’un habitat «intelligent»

The advent of new technologies in the field of data processing, electronics and wireless communications currently support the integration of essential functions for the provision of services tailored to the user needs at home. These services are destined to address two key societal demands, i.e., keeping health costs and energy costs under control. With this objective in mind, a number of research works involving various approaches have been conducted as those carried out atlaas for the purpose of integrating the habits and practices of home automation users. The principles under investigation rely on learning habits. Two examples of application using these concepts are presented through use of two home automation systems for a personalized behavioral monitoring of the elderly with a view to providing home care, and for the automatic management of thermal comfort. Promising results have been obtained and pave the way for efficient and cost effective systems that could be associated with other functions to contribute to the development of a truly «smart home».     

Architecture d’un réseau actif à base de services Web

This paper presents a novel active architecture for building and deploying network services:aswa, Web Services based Active network Architecture. At the architectural level,aswa defines an active node whose functionalities are divided into the Node Operating System, the Execution Environment, and the Active Applications. At the implementation level,aswa is a Web Services based platform where new components could be added and deployed, in order to dynamically modify network nodes behavior. Applications can be developed with any language and communicate across heterogeneous environments, and across Internet and Intranet structures. At the deployment levelaswa uses an active node approach, and offers a controlled deployment mode. In terms of security, Authentication of deployed code and protection of the nodes is achieved by the use ofhttps and the header extensions of thesoap envelope. Finally to validate this architecture,aswa defines a Firewall as an Active Application to secure the code deployment.     

Utilisation d’un analyseur syntaxique pour la reconnaissance de la parole continue

The author describes the syntactic analyzer which is used in the system keal for continuous speech recognition. After detection of the words in an utterance by a lexical analyzer, the syntactic analyzer builds all the possible syntactic structures according to a context free grammar previously defined by means of a compiled metalanguage. This analyzer allows, in some cases, to correct some errors such as omission and insertion of phonemes by the phonemic analyzer, or non-detection of short words by the lexical analyzer. This program enables presently the recognition of 65 % of utterances in simple dialogs. A few seconds are enough to recognize a sentence.