Limoges, France
Limoges, France

Time filter

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Bernard A.,XLIM | Gama N.,National Engineering School of Caen
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

We present a variant of the Lagrange-Gauss reduction of quadratic forms designed to minimize the norm of the reduction matrix within a quadratic complexity. The matrix computed by our algorithm on the input f has norm , which is the square root of the best previously known bounds using classical algorithms. This new bound allows us to fully prove the heuristic lattice based attack against NICE Cryptosystems, which consists in factoring a particular subclass of integers of the form pq 2. In the process, we set up a homogeneous variant of Boneh-Durfee-HowgraveGraham's algorithm which finds small rational roots of a polynomial modulo unknown divisors. Such algorithm can also be used to speed-up factorization of pq r for large r. © 2010 Springer-Verlag Berlin Heidelberg.


Carsenat D.,MINACOM | Crunteanu A.,MINACOM | Chatras M.,MINACOM | Passerieux D.,XLIM
IEEE Antennas and Wireless Propagation Letters | Year: 2015

Surface acoustic wave (SAW) filters have been developed to code the information received by an antenna array and sum them into a single signal. In post-processing, these waveforms are retrieved exploiting the orthogonal propagation in each SAW filter. Thus, a proof a concept of beamforming and imaging using SAW filters is presented. © 2002-2011 IEEE.


Casagrande R.,GERAC | Maurice O.,GERAC | Reineix A.,XLIM
IEEE International Symposium on Electromagnetic Compatibility | Year: 2013

The purpose of the paper is to model cable bundles in the high frequency range. The principle of the model is based on the combination of the Vabre's and Branin's equations. The calculation uses the Kron's method applied to EMC. The calculation results are checked by experimental tests. © 2013 EMC Europe Foundation.


Toubet M.S.,XLIM | Chantalat R.,XLIM | Hajj M.,CISTEME | Jecko B.,CISTEME | Diot J.C.,CEA Cesta
Proceedings of 6th European Conference on Antennas and Propagation, EuCAP 2012 | Year: 2012

In this paper, we present a Wide Bandwidth (71%), ultra Low-Profile (<λ/10) and High-Gain (17 dB) EBG antenna which is used for high power and electronic warfare applications. A prototype of this modelized antenna is manufactured and the measured performances are compared to the simulated ones. © 2012 IEEE.


Baron T.,University of Franche Comte | Gachon D.,University of Franche Comte | Romand J.P.,University of Franche Comte | Alzuaga S.,University of Franche Comte | And 4 more authors.
2010 IEEE International Frequency Control Symposium, FCS 2010 | Year: 2010

In this work, we propose a pressure sensor fabricated on compound LiNbO3/Silicon/Silicon substrates obtained by Au/Au bonding at room temperature and double face lapping/polishing of LiNbO3/silicon stack and a final gold bonding with a structured silicon wafer. Sensitivity of the final sensor to bending moments then is tested and results show pressure sensitivity of such devices. ©2010 IEEE.


Jardel O.,III V Laboratory | Laurent S.,XLIM | Reveyrand T.,XLIM | Quere R.,XLIM | And 5 more authors.
IEEE MTT-S International Microwave Symposium Digest | Year: 2013

We propose here a non-linear GaN HEMT model for CAD including a trapping effects description consistent with both small-signal and large-signal operating modes. It takes into account the dynamics of the traps and then allows to accurately model the modulated large signal characteristics that are encountered in telecommunication and radar signals. This model is elaborated through low-frequency S-parameter measurements complementary to more classical pulsed-IV characterizations. A 8×75μm AlInN/GaN HEMT model was designed and particularly validated in large-signal pulsed RF operation. It is also shown that thermal and trapping effects have opposite effects on the output conductance, thus opening the way for separate characterizations of the two effects. © 2013 IEEE.


Hamani R.,NXP Semiconductors | Andrei C.,NXP Semiconductors | Jarry B.,XLIM | Lintignat J.,XLIM
IEEE International Conference on Microelectronic Test Structures | Year: 2014

This paper, presents a novel methodology for small signal equivalent circuit extraction suitable for high frequency characterization up to mm-wave range. This methodology allows the de-embedding and the extraction of RF characteristics by the use of a smart matching at 50Ω of the transistor connected in GSG probe pads. The method has been validated first on a test module based on RFMOS transistor fabricated in BiCMOS 0.25μm technology from NXP Semiconductors. The results of matched RFMOS transistors at 30.5GHz are presented here and show good agreement between measurements/extractions and calculations (e.g. for Cgs). Second, a bipolar transistor matched test structure is investigated. An improvement of transmission gain of matched test structured from-12dB to-0.2dB has been found using measurements and simulated data. © 2014 IEEE.


Bohl E.,XLIM | Terraz O.,XLIM | Ghazanfarpour D.,XLIM
Visual Computer | Year: 2015

Modeling a fruit using classic 3D modeling software can be a relatively complicated task. Moreover, modeling every single fruit when we need to generate a large variety of fruits of the same species is not a viable option because it is time consuming. This paper presents an original ad hoc method for modeling a wide range of 3D fruits, using a single formal grammar. Fruits are modeled by parametric 3Gmap L-systems that describe their shape and internal structure, thanks to variables and mathematical functions. At the end of our work, our method will eventually be an interesting solution to realistic modeling of fruits and their interior, and to automatic detection and recognition of real fruits. © 2015, Springer-Verlag Berlin Heidelberg.


Chreim H.,XLIM | Kanso A.,XLIM | Arnaud E.,XLIM | Menudier C.,XLIM | Monediere T.,XLIM
Microwave and Optical Technology Letters | Year: 2014

This article describes the design of an ultrawide band (UWB) biconical antenna operating in the 400-3000 MHz frequency band. The antenna will be used for high-rate communication applications. The method for designing an UWB biconical antenna will be given. As the antenna must operate starting from 400 MHz, the size of the designed antenna will exceed the dimensions constraints, required in the specifications. Thus, the antenna edges are curved, which allows us to decreasing its dimensions while keeping the same performances. Finally, a prototype of the antenna is fabricated and measured, and the measured results are compared to the simulated ones. © 2014 Wiley Periodicals, Inc.


Bouyeron L.,XLIM | Olivier S.,XLIM | Delage L.,XLIM | Reynaud F.,XLIM | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2010

In this paper, we report the first experimental demonstration of a temporal hypertelescope (THT). Our breadboard including eight telescopes is first tested in a manual cophasing configuration on a one-dimensional object. The point-spread function (PSF) is measured and exhibits dynamics in the range of 300. A quantitative analysis of the potential biases demonstrates that this limitation is related to the residual-phase fluctuation on each interferometric arm. Secondly, an unbalanced binary star is imaged, demonstrating the imaging capability of THTs. In addition, a two-dimensional PSF is recorded, even if the telescope array is not optimized for this purpose. © 2010 The Authors. Journal compilation © 2010 RAS.

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