Hagenmeyer V.,BASF |
Delaleau E.,Brest National School of Engineering |
Delaleau E.,European University of Brittany
IEEE Transactions on Automatic Control | Year: 2010
A methodology to analyze robustness with respect to exogenous perturbations for exact feedforward linearization based on differential flatness is presented. The analysis takes into consideration the tracking error equation and makes thereafter use of a stability result by Kelemen coupled with results issued from interval analysis. This turns exact feedforward linearization based on differential flatness into a general control methodology for flat systems. © 2010 IEEE.
Tabbache B.,CNRS Brest Laboratory of Mechanics and Systems Laboratory |
Tabbache B.,Polytechnic School of Algiers |
Benbouzid M.E.H.,CNRS Brest Laboratory of Mechanics and Systems Laboratory |
Kheloui A.,Polytechnic School of Algiers |
Bourgeot J.-M.,Brest National School of Engineering
IEEE Transactions on Vehicular Technology | Year: 2013
This paper describes a sensor fault-tolerant control (FTC) for electric-vehicle (EV) powertrains. The proposed strategy deals with speed sensor failure detection and isolation within a reconfigurable induction-motor direct torque control (DTC) scheme. To increase the vehicle powertrain reliability regarding speed sensor failures, a maximum-likelihood voting (MLV) algorithm is adopted. It uses two virtual sensors [extended Kalman filter (EKF) and a Luenberger observer (LO)] and a speed sensor. Experiments on an induction-motor drive and simulations on an EV are carried out using a European urban and extraurban driving cycle to show that the proposed sensor FTC approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. © 2012 IEEE.
Ganier F.,University of Western Brittany |
Hoareau C.,University of Western Brittany |
Tisseau J.,Brest National School of Engineering
Ergonomics | Year: 2014
Virtual reality opens new opportunities for operator training in complex tasks. It lowers costs and has fewer constraints than traditional training. The ultimate goal of virtual training is to transfer knowledge gained in a virtual environment to an actual real-world setting. This study tested whether a maintenance procedure could be learnt equally well by virtual-environment and conventional training. Forty-two adults were divided into three equally sized groups: virtual training (GVT® [generic virtual training]), conventional training (using a real tank suspension and preparation station) and control (no training). Participants then performed the procedure individually in the real environment. Both training types (conventional and virtual) produced similar levels of performance when the procedure was carried out in real conditions. Performance level for the two trained groups was better in terms of success and time taken to complete the task, time spent consulting job instructions and number of times the instructor provided guidance. Practitioner Summary: A key issue for virtual environments for training (VETs) is the transfer of skills to real situations. An experiment investigated whether skills acquired in a VET could be applied in a real situation. Results suggest that a procedure can be successfully transferred from the virtual to the real. © 2014 © 2014 Taylor & Francis.
Gedouin P.-A.,Brest National School of Engineering |
Chirani S.A.,Brest National School of Engineering |
Chirani S.A.,CNRS Brest Laboratory of Mechanics and Systems Laboratory |
Calloch S.,CNRS Brest Laboratory of Mechanics and Systems Laboratory
International Journal of Plasticity | Year: 2010
The microstructure of shape memory alloys changes with the thermomechanical history of the material. During thermomechanical loading, austenite, thermally-induced martensite or stress-induced martensite can be simultaneously present in the material. In applications integrating SMA parts, utilization conditions seriously affect the microstructure and can generate macroscopic strain or stress. Consequently, during thermomechanical loadings, it is important to be able to proportion the different phases and consequently to understand the kinetic transformation. This is very useful in the development of constitutive equations. This study shows, by a series of tests, that the proposed experimental method, based on the measurement of the variation of electric resistance of CuAlBe wires, permits to determine the volume fraction of the different phases present in the material (i.e., austenite, stress-induced martensite and thermally-induced martensite). The proposed method is applied to the most common thermomechanical behavior met in engineering applications of shape memory alloys: pseudoelasticity, pseudoplasticity, recovery-stress and stress-assisted two-way shape memory effect. The proportioning method based on a mixture law integrating the resistivity of pure phases present in the SMA is first performed on different two-phase mixture cases and then applied to a three phase mixture case. © 2009 Elsevier Ltd. All rights reserved.
Zoiros K.E.,Democritus University of Thrace |
Morel P.,Brest National School of Engineering
AIP Advances | Year: 2014
We employ a birefringent fiber loop (BFL) for enhancing the performance of a semiconductor optical amplifier (SOA) which is directly modulated. By properly exploiting the BFL comb-like spectral response, we show that the SOA can be directly modulated at a data rate which is more than five times faster than that enabled by the SOA electrical bandwidth. The experimental results, which include chirp measurements, demonstrate the significant improvements achieved in the performance of the directly modulated SOA with the help of the BFL. © 2014 Author(s).
Nasreddine K.,Brest National School of Engineering |
Benzinou A.,Brest National School of Engineering |
Fablet R.,Telecom Bretagne
Pattern Recognition Letters | Year: 2010
In this paper we define a multi-scale distance between shapes based on geodesics in the shape space. The proposed distance, robust to outliers, uses shape matching to compare shapes locally. The multi-scale analysis is introduced in order to address local and global variabilities. The resulting similarity measure is invariant to translation, rotation and scaling independently of constraints or landmarks, but constraints can be added to the approach formulation when needed. An evaluation of the proposed approach is reported for shape classification and shape retrieval on the part B of the MPEG-7 shape database. The proposed approach is shown to significantly outperform previous works and reaches 89.05% of retrieval accuracy and 98.86% of correct classification rate. © 2009 Elsevier B.V. All rights reserved.
Khaleghi H.,Brest National School of Engineering |
Morel P.,Brest National School of Engineering |
Sharaiha A.,Brest National School of Engineering |
Rampone T.,Brest National School of Engineering
Journal of Lightwave Technology | Year: 2013
In this paper, a numerical model of Semiconductor Optical Amplifiers (SOA) is experimentally validated in terms of the Alpha Factor αH and the Four-Wave Mixing (FWM). Besides, a Coherent Optical-Orthogonal Frequency Division Multiplexing (CO-OFDM) simulation platform is used to confirm the good agreement between the measured and the simulated Error Vector Magnitude (EVM) of a received signal amplified by the studied SOA in an optical transmission link. In addition, the performance of the SOA on the amplification of a 10.94 Gb/s QPSK CO-OFDM signal is numerically analyzed with respect to the Amplified Spontaneous Emission (ASE) noise, the Alpha Factor, the output saturation power of the SOA and the bit rate. © 2012 IEEE.
Bohemond C.,Brest National School of Engineering |
Rampone T.,Brest National School of Engineering |
Sharaiha A.,Brest National School of Engineering
Journal of Lightwave Technology | Year: 2011
The key goal of this paper consists of a theoretical and an experimental performances analysis of a photonic microwave mixer used as a signal down- and up-converter based on cross-gain modulation in a semiconductor optical amplifier (SOA). We give, by a small-signal analysis approach, the analytical equations of the output optical power carrying the down- and up-converted signal. Simplified formulas are developed, relating the mixing conversion gain to the modeling parameters of the SOA. The efficiency of the photonic microwave mixer based on an SOA has been evaluated in terms of mixing conversion gain, third-order input intercept point, and electrical phase noise. In addition, a subcarrier modulated by a QPSK, a 16 quadratic-amplitude modulation (QAM) and a 64 QAM at a data rate of 270 ksymb/s has been down converted from 1 GHz to 100 MHz with a low error vector magnitude of about 3.5%. © 2011 IEEE.
Buche C.,Brest National School of Engineering |
Querrec R.,Brest National School of Engineering
Expert Systems with Applications | Year: 2011
This research is situated within the context of the creation of human learning environments using virtual reality. We propose the integration of a generic and adaptable intelligent tutoring system (Pegase). The aim is to instruct the learner, and to assist the instructor. The multi-agent system emits a set of knowledge (actions carried out by the learner, knowledge of the field, etc.) used by an artificial intelligence to make pedagogical decisions. Our study focuses on the representation of knowledge about the environment, and on the adaptable pedagogical agent providing instructive assistance. © 2011 Elsevier Ltd. All rights reserved.
Polceanu M.,Brest National School of Engineering
IEEE Conference on Computatonal Intelligence and Games, CIG | Year: 2013
Believability of automated characters in virtual worlds has posed a challenge for many years. In this paper, the author discusses a novel approach of using human-inspired mirroring behavior in MirrorBot, an Unreal Tournament 2004 game bot which crossed the humanness barrier and won the 2K BotPrize 2012 competition with the score of 52.2%, a record in the five year history of this contest. A comparison with past contest entries is presented and the relevance of the mirroring behavior as a humanness improvement factor is argued. The modules that compose MirrorBot's architecture are presented along with a discussion of the advantages of this approach and proposed solutions for its drawbacks. The contribution continues with a discussion of the bot's results in humanness and judging accuracy. © 2013 IEEE.