Ecole Nationale de l'Aviation Civile
Toutes les publications de l'ENAC en direct.
All ENAC publications.
Corona discharge modeling mostly relies on two, mostly distinct, approaches: high-fidelity, numerically challenging, unsteady simulations having high-computational cost or low-fidelity simulations based on empirical assumptions such as constant electric field at the emitter electrode. For the purpose of steady discharge current predictions, high-fidelity models are very costly to use whilst empirical models have limited range of validity owing the subtle use of tuned parameters. We propose an intermediate approach: an asymptotic multi-scale/two-domain numerical modeling based upon generalizing previous asymptotic axi-symmetrical analysis [1,2]. We show how the initial...
As an alternative method to the discrete split-step Fourier method, the split-step wavelet method has recently been derived. This method based on a wavelet decomposition of the field is efficient and accurate in simulating the long-range propagation of electromagnetic waves in the low troposphere. In this paper, to further improve the computational efficiency and take full advantage of wavelet characteristics, a waveletto-wavelet propagation method is proposed. The propagation, variable refractivity, and apodization are accounted in the wavelet domain. The computational complexity is reduced, since no transforms are performed between wave fields and wavelet coefficients...
Eye movements are particularly important in aeronautics where operators rely on numerous sources of visual information. Eye-tracking reveals what we are looking at, but also the physical and psychological condition of an operator. The human perception, and more particularly the vision, is a vector of errors well known in human factors (tunnel effect, eye strain, etc.). The eyes can help finding where the attention is focused (gaze position), how the subject feels (fatigue), and interact with a system by eye movements [1]. Ocular interactions meet the need that HOTAS commands in aircraft are complexified by the high number of buttons and complex multiplexing. Oculometry...
Modeling the long-range propagation in the low troposphere is a topic of major concern for many systems such as radar. In 3D, split-step Fourier methods are limited by both computation time and memory size. Therefore, the N times 2D split-step Fourier method is usually used to model the propagation even if 3D effects are not taken into account. To overcome this, we propose a 3D wavelet-based split-step method that is memory and time efficient. This method is based on the use of the fast wavelet transform, which is of low complexity and allows efficient sparse representations. From numerical experiments, we show that the 3D proposed split-step wavelet method is efficient...
Widely linear (WL) receivers have been developed in the past for single antenna interference cancel- lation (SAIC) of one rectilinear (R) or quasi-rectilinear (QR) data-like multi-user interference (MUI) or co-channel interference (CCI) in particular. The SAIC technology has been implemented in global system for mobile communications (GSM) handsets in particular and has been further analyzed for voice ser- vices over adaptive multi-user channels on one slot (VAMOS) standard. It remains of great interest for several current and future applications using R or QR signals, such as anti-collisions processing in radio frequency identification (RFID) or in satellite-AIS systems...
Cet article s’inscrit dans le cadre de notre doctorat, codirigé par Alain Bonardi et Jean-Marc Chouvel. Il propose une étude de l’électronique de Répons (1984) de Pierre Boulez (1925-2016). Son objectif est de mettre à jour un choix musical déterminant dans la composition de Répons, à partir de l’analyse de l’utilisation de l’électronique dans cette œuvre. L’article se concentre sur les différents types d’utilisation d’une ligne à retard numérique en temps réel dans Répons, en tant que traitement sonore inédit et omniprésent. La création de Répons, le 18 octobre 1981 à Donaueschingen, inaugure en effet la 4X, premier processeur de son numérique en temps réel. Plusieurs...
This paper presents Trajectory Score Library, an Antescofo library of scripts, converting mathematical parametric functions into curves in order to control the Spat5 sources trajectories. These scripts are written in the Antescofo language, a timed synchronous language which allows the use of relative time to synchronize the trajectories with musical events. This language can also provide a convenient way of creating and transmitting automation parameters to the Spat5 through the Open Sound Control protocol implemented in Ascrentescofo. Trajectory Score Library is an additional tool amongst existing spatialization solutions. In the context of this presentation these...
L’objectif au cœur de la systémique, définie par Ludwig von Bertalanffy comme une maxime méthodologique, est de fournir « une façon de voir les hoses qui autrefois étaient négligées ou contournées 1 ». Notre approche, qui s’attache au développement d’une compétence spécifique aux angages musicaux inspirés par l’informatique, ne vise pas à approfondir l’analyse musicale en détail, mais plutôt à comprendre le sens global d’une œuvre en fonction de son évolution dynamique. Ainsi, en définissant une méthodologie pour la modélisation de l’œuvre musicale, il sera possible dorénavant de mettre en lumière certains éléments souvent laissés dans l’ombre, tels que des dimensions...