Taghizad A.,ONERA |
Biannic J.-M.,ONERA |
5th Asian-Australian Rotorcraft Forum, ARF 2016 | Year: 2016
The complexity of helicopter flight dynamics combined to an increasing demand to improve its mission performance are two sources of difficulties for the efficient design of helicopter flight control systems. Handling qualities requirements, as specified in ADS-33 standards (Ref. 1) provide a useful guideline for control laws design. The right selection of the criteria in relation with the helicopter planned missions (MTEs) and the usable cues to realize them (UCE) can ensure an optimized design of the control system. However, designing robust control laws with such constrained requirements remains a challenging task. Recent activities at ONERA have led to the development of an approach to integrate handling qualities requirements in robust control design techniques. As a first step Handling Qualities charts are generated using an equivalent model of a conventional PID controller for an Attitude Command Attitude Hold (ACAH) control law. After what the charts are used to feed robust control design tools. The paper presents the charts, their validation process and their use in ONERA robust control design environment. Copyright © 2016 by the American Helicopter Society International, Inc. All rights reserved.
Yang Y.,ENSEEIHT |
Memin E.,French Institute for Research in Computer Science and Automation
Tellus, Series A: Dynamic Meteorology and Oceanography | Year: 2017
In this paper, we explore a dynamical formulation allowing to assimilate high-resolution data in a large-scale fluid flow model. This large-scale formulation relies on a random modelling of the small-scale velocity component and allows to take into account the scale discrepancy between the dynamics and the observations. It introduces a subgrid stress tensor that naturally emerges from a modified Reynolds transport theorem adapted to this stochastic representation of the flow. This principle is used within a stochastic shallow water model coupled with an 4DEnVar assimilation technique to estimate both the flow initial conditions and the inhomogeneous time-varying subgrid parameters. The performance of this modelling has been assessed numerically with both synthetic and real-world data. Our strategy has shown to be very effective in providing a more relevant prior/posterior ensemble in terms of the dispersion compared to other tests using the standard shallow water equations with no subgrid parameterization or with simple eddy viscosity models.We also compared two localization techniques. The results indicate the localized covariance approach is more suitable to deal with the scale discrepancy-related errors. © 2017 The Author(s).
News Article | December 20, 2016
With constant evolution of technology, brand manufacturers and their procurement teams need to be confident that the electronic parts used in their products are of the required quality and reliable. This is where the IECQ comes in. Its goal is to minimize costs associated with incoming inspection and quality auditing of suppliers when a manufacturer sources components with IECQ product certification. Bureau Veritas' Marie-Elisabeth d'Ornano, the Chair of IECQ since January 2014, has recently been recognized by the IEC for her outstanding contribution at the Thomas Edison Awards. The IEC Website states, "...Marie-Elisabeth d'Ornano embraced her role, responsibilities and duties with enthusiasm and a dynamic hands-on approach. In this role, she has had the strong support of her employer, LCIE - a Bureau Veritas company. IECQ has been reinforced as an international "best practice" model for supplier assessment and as an extremely valuable Supply Chain Management tool for the many industries involved in the manufacture, supply and distribution of electrical/electronic components, parts and assemblies. During her initial term as Chair, IECQ has benefited from d'Ornano's leadership as illustrated in a number of key initiatives and achievements: Marie-Elisabeth d'Ornano has a Masters in Engineering from ENSEEIHT, the University for Electronic Engineering, Electronics, Computer Science, Hydraulics and Telecommunications in Paris, France, and a Masters in Management of Technology and Innovation from the University Dauphine, Paris, France. After completing her studies, Marie-Elisabeth worked first for Electricité de France (EDF), the French public utility with worldwide activities, and then for the French branch of the Swiss company, ASCOM, a leader in the telecommunications sector. In 2005, Marie-Elisabeth joined LCIE Bureau Veritas in France. Initially responsible for the transportation, aeronautics and defense markets, Marie-Elisabeth has additionally managed the training and consulting activities and is now looking after Bureau Veritas' LCIE global certification and eco-design businesses. The IECQ is a worldwide approval and certification system covering the supply of electronic components and associated materials and assemblies (including modules) and processes. It uses quality assessment specifications that are based on International Standards prepared by the International Electrotechnical Commission (IEC). IECQ QC 080000 (Hazardous Substance Process Management System Requirements) provides manufacturers with a tool that makes it easier for them to produce "clean" products and to comply with the increasingly tough requirements and legislation that restrict the use of hazardous substances in electronic products and components. Created in 2010, the Thomas A. Edison Award recognizes exceptional achievement (within the past five years), dedicated service and significant contributions to the IEC through the effective management of committees of currently active TC/SC Officers (Chair, Secretary or Assistant Secretary of a Technical Committee or Subcommittee) and officers of the IEC Conformity Assessment Systems and their subsidiary bodies. Bureau Veritas is a global leader in testing, inspection and certification services. Founded in 1828, the group has more than 68,400 employees in around 1,400 offices and laboratories all across the world. Bureau Veritas helps its clients to improve their performances by offering innovative services and solutions in order to ensure that their products, infrastructure and processes meet standards and regulations in terms of quality, health and safety, environment protection and social responsibility. Website: http://www.bureauveritas.com Bureau Veritas' Consumer Products Services division is a leading global quality assurance provider for the global consumer product and retail markets. It offers an array of specialized services including testing, inspections, certification, audits and engineering services for a wide range of consumer products. These products include soft goods; electrical and electronic products; smartworld products and services including wireless and mobile devices; automotive equipment; hard goods; toys and juvenile products; premiums; food products as well as health, beauty, cosmetics, and household products. Website: http://www.bureauveritas.com/cps
Gratton S.,ENSEEIHT |
Toint P.L.,University of Namur |
Troltzsch A.,European Center for Research and Advanced Training in Scientific Computation
Optimization Methods and Software | Year: 2011
We consider an implementation of a recursive model-based active-set trust-region method for solving bound-constrained nonlinear non-convex optimization problems without derivatives using the technique of self-correcting geometry proposed in K. Scheinberg and Ph.L. Toint [Self-correcting geometry in model-based algorithms for derivative-free unconstrained optimization. SIAM Journal on Optimization, (to appear), 2010]. Considering an active-set method in bound-constrained model-based optimization creates the opportunity of saving a substantial amount of function evaluations. It allows US to maintain much smaller interpolation sets while proceeding optimization in lower-dimensional subspaces. The resulting algorithm is shown to be numerically competitive. © 2011 Taylor & Francis.
Arioli M.,Rutherford Appleton Laboratory |
Gratton S.,ENSEEIHT |
Gratton S.,European Center for Research and Advanced Training in Scientific Computation
Computer Physics Communications | Year: 2012
Minimum-variance unbiased estimates for linear regression models can be obtained by solving least-squares problems. The conjugate gradient method can be successfully used in solving the symmetric and positive definite normal equations obtained from these least-squares problems. Taking into account the results of Golub and Meurant (1997, 2009) [10,11], Hestenes and Stiefel (1952) , and Strakoš and Tich (2002) , which make it possible to approximate the energy norm of the error during the conjugate gradient iterative process, we adapt the stopping criterion introduced by Arioli (2005)  to the normal equations taking into account the statistical properties of the underpinning linear regression problem. Moreover, we show how the energy norm of the error is linked to the χ2-distribution and to the Fisher-Snedecor distribution. Finally, we present the results of several numerical tests that experimentally validate the effectiveness of our stopping criteria. © 2012 Elsevier B.V. All rights reserved.
Khodja A.,A.P.S. University |
Yagoub M.C.E.,University of Ottawa |
Touhami R.,A.P.S. University |
International Journal of RF and Microwave Computer-Aided Engineering | Year: 2013
To sustain the ever-increasing use of coupled-line structures in RF/microwave systems, efficient design tools should be developed. In this article, an original approach combining accuracy and speediness is proposed to shorten time-to-market design cycles when such structures are involved. By introducing the quasi-symmetric approach, CPU-time required to analyze asymmetric coupled-lines can be significantly reduced, leading to faster models without sacrificing the overall design accuracy. To achieve this aim, a rigorous formulation was developed and, for the first time, trial functions of C- and π-modes were obtained from the quasi-symmetric case and applied to the asymmetric case. The proposed approach, easily implementable in commercial simulators, was demonstrated through comparisons with published data. Copyright © 2012 Wiley Periodicals, Inc.
Marques O.,Florida Atlantic University |
Barenholtz E.,Florida Atlantic University |
Multimedia Tools and Applications | Year: 2011
In recent years there has been a surge of interest in context modeling for numerous applications in computer vision. The basic motivation behind these diverse efforts is generally the same-attempting to enhance current image analysis technologies by incorporating information from outside the target object, including scene analysis as well as metadata. However, many different approaches and applications have been proposed, leading to a somewhat inchoate literature that can be difficult to navigate. The current paper provides a 'roadmap' of this new research, including a discussion of the basic motivation behind context-modeling, an overview of the most representative techniques, and a discussion of specific applications in which contextual modeling has been incorporated. This review is intended to introduce researchers in computer vision and image analysis to this increasingly important field as well as provide a reference for those who may wish to incorporate context modeling in their own work. © 2010 Springer Science+Business Media, LLC.
Hayouni M.,University of Carthage |
El Oualkadi A.,LabTIC |
Choubani F.,University of Carthage |
Vuong T.H.,ENSEEIHT |
Progress in Electromagnetics Research Letters | Year: 2012
In this paper, antenna ultra wideband enhancement by non-uniform matching is proposed. The antenna consisted of a rectangular shaped radiator with two convex circled corners. Simulated results using CST Microwave Studio and measured results of a fabricated antenna concord well to prove that it can operate from about 3.5 GHz to 4.6 GHz and from 7.4 GHz to 12.7 GHz for S 11(dB) < -10 dB. In addition, a good impedance matching is noted in the IEEE radar engineering X band range since the return loss coe±cient remains below -50 dB value at 9.5 GHz and can reach -45 dB at 11 GHz. A current density comparison at 11 GHz, supporting our argument, between a stepper corner and convex corner demonstrates that the current density can reach 52A/m with a convex corner whereas it does not exceed 33A/m for the antenna with a stepper corners. Radiation patterns at various frequencies and peak gains show clearly interesting features of such antennas.
Dakhli N.,Research Unit of Telecommunication Systems 6Tel at supCom |
Choubani F.,Research Unit of Telecommunication Systems 6Tel at supCom |
Applied Physics A: Materials Science and Processing | Year: 2011
A novel resonant metamaterial antenna based on the Composite Right/Left-Handed (CRLH) transmission line (TL) model is presented. The proposed small antenna is designed to operate simultaneously over multiple wireless services (UMTS-WLAN-WIMAX) © 2011 Springer-Verlag.
Chabert M.,ENSEEIHT |
European Signal Processing Conference | Year: 2015
This paper addresses the problem of AC detection in multiplicative noise using the Continuous Wavelet Transform (CWT) and possible non-linear preprocessing. The quadratic pre-processing is shown to improve the performance of signature-based time-scale detectors under specific conditions on noise and signal parameters. © 2000 EUSIPCO.