Matra

About: Matra is a based out in . It is known for research contribution in the topics: Signal & Detector. The organization has 1330 authors who have published 1216 publications receiving 17967 citations.

Evaluation of root-normalised front-end (RN LFCC) for speech recognition in wireless GSM network environments

Abstract: With the emergence of mobile telephony, the conditions of use of speech recognisers have been completely reconsidered. Speech can be input from a wide range of environments, having to face several degradation causes principally induced by noise and/or channel distortions. The root-normalised front-end is evaluated on several databases. Special attention is given to the GSM environment where noise, channel and coder effects are analysed. Experimental results indicate that this analysis model, when compared to the more conventional mel-scale cepstral representation (MFCC), is proved to be more robust to several types of perturbations. This advantage is maintained when using explicit channel and noise compensation schemes such as NSS (non-linear spectral subtraction).

Foundation of a computable solid modeling

Abstract: Solid modelling and computational geometry are based on classical topology and geometry in which the basic predicates and operations, such as membership, subset inclusion, union and intersection, are not continuous and therefore not computable. But a sound computational framework for solids and geometry can only be built in a framework with computable predicates and operations. In practice, correctness of algorithms in computational geometry is usually proved using the unrealistic Real RAM machine model of computation, which allows comparison of real numbers, with the undesirable result that correct algorithms, when implemented, turn into unreliable programs. Here, we use a domain-theoretic approach to recursive analysis to develop the basis of an e3ective and realistic framework for solid modelling. This framework is equipped with a well de5ned and realistic notion of computability which re6ects the observable properties of real solids. The basic predicates and operations on solids are computable in this model which admits regular and non-regular sets and supports a design methodology for actual robust algorithms. Moreover, the model is able to capture the uncertainties of input data in actual CAD situations. c 2002 Elsevier Science B.V. All rights reserved.

Method of connecting the output pads on an integrated circuit chip, and multichip module thus obtained

Abstract: The chip is fixed to a substrate by its lower face. At least one wire-bonding adaptor in the form of a board is used, the upper face of which has first bonding pads along at least one first edge and second bonding pads along at least one second edge, and including electrical connections between the first and second bonding pads. The wire-bonding adaptor is adhesively bonded by its lower face to the upper face of the chip so that the said first edge is adjacent to a row of output pads located elsewhere than on the periphery of the upper face of the chip and so that the said second edge is adjacent to the periphery of the chip. Bonding wires are bonded, on the one hand, between the output pads of the said row and the first bonding pads and, on the other hand, between the second bonding pads and conducting pads on the substrate.

Control for variable reluctance motors

Abstract: A control for a variable reluctance motor, comprising a d.c. source, a power control circuit, and a command circuit, in which the power control circuit comprises main control switches in series with the windings of the motor to form terminal branches, the terminal branches being connected in groups of two in series between the two poles of the source in such a way that two complementary windings are never in series, as well as free-wheel branches to close the circuit of each winding when at most one main control switch in a branch is conducting, and a turn-off circuit for the main control switches, and including at least one current detector to register the current in the windings; each free-wheel branch includes a coil and a diode, the diode polarized to oppose normal current flow through its associated main control switch.

Effects of material and/or structure on shielding of electronic devices

Abstract: In this paper, we have pioneered a new direction concerning the shielding of electronic devices (at a microcircuit-packaging or a larger level) in a radiative environment. As a matter of fact, this work not only considers the role of the material itself on the shielding efficiency but also the effect of the structure of the shield. By simulations with the NOVICE Code, we have explored the possibility of combining the specific attenuation properties of given materials in an optimized multilayer (and multimaterial) structure. This study is based on a brief theoretical overview of interaction of space radiation with material. Then, the results of simulations are presented. The workframe of these calculations is a worst-case geosynchronous orbit (160/spl deg/ West) for a period of 15 years (trapped electrons and protons from 4 anomalously large solar particle events). We found that it is possible to improve the shielding properties of a monomaterial absorber by using an optimized multilayer, multimaterial shield.