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Toutes les publications de l'ENAC en direct.
All ENAC publications.

[hal-01896749] Model-Free Control Approach for Fixed-Wing UAVs with Uncertain Parameters Analysis

Publications ENAC - Friday, 19 October 2018 - 19:10:46
This paper presents first results of an innovative Model-Free Control (MFC) architecture applied to fixed-wing UAVs. MFC is an algorithm dedicated to systems with poor modeling knowledge. Indeed, the costs to derive a reliable and representative aerodynamic model for UAVs motivated the use of such a controller. By exploiting a purely numerical model, this algorithm provides an intuitive method to tune the control loop without any information about the controlled system. We propose to extend the MFC architecture to the case of fixed-wing UAVs and study the MFC properties in terms of uncertain parameters. As a first result, our designed MFC architecture provides a...

[hal-01897108] Modeling flight delay propagation in airport and airspace network

Publications ENAC - Friday, 19 October 2018 - 18:55:10
An Airport-Sector Network Delays model is developed in this paper for flight delay estimation within air transport network. This model takes both airports and airspace capacities into account by iterating among its three main components: a queuing engine, which treats each airport in the network as a queuing system and is used to compute delays at individual airport, a Link Transmission Model, which computes delays at individual sector and transmits all air delays into ground delays, and a delay propagation algorithm that updates flight itineraries and demand rates at each airport on the basis of the local delays computed by the queuing engine and flow control delays...

[tel-01894861] Bundling : une Technique de Réduction d'Occultation par Agrégation Visuelle et son Application à l'Étude de la Maladie d'Alzheimer

Publications ENAC - Wednesday, 17 October 2018 - 18:18:35
Le big data est un challenge majeur de la visualisation ; l’augmentation du nombre de données à visualiser augmente la densité et l’occultation des graphes et il devient difficile de distinguer les éléments qui le compose. Pour résoudre ce challenge, plusieurs techniques de visualisation se focalisent sur la simplification visuelle ; parmi elles, l’agréga- tion visuelle (bundling) permet l’agrégation des liens pour créer des zones de fortes densités au profit d’espaces plus clairsemés faisant ainsi émerger des structures visuelles. Cette thèse s’efforce à faire le trait d’union entre la complexité technique des algorithmes de bundling et les utilisateurs finaux. Dans un...

[hal-01893968] The pwpfit Toolbox for Polynomial and Piece-wise Polynomial Data Fitting

Publications ENAC - Tuesday, 16 October 2018 - 19:38:25
Several techniques have been proposed for piece-wise regression as extension to standard polynomial data fitting, either selecting the joints a priori or adding computational load for optimal joints. The pwpfit toolbox provides piece-wise polynomial fitting without pre-selection of joints using linear-least square (LSQ) optimization only. Additional constraints are realised as constraint matrices for the LSQ problem. We give an application example for the multi-variable aerodynamic coefficients of the general transport model in pre-stall and post-stall.

[hal-01886536] Design of a novel network intrusion detection system for drone communications

Publications ENAC - Wednesday, 10 October 2018 - 16:34:14
This paper proposes an hybrid method based on both a spectral traffic analysis and a robust controller / observer for anomaly estimation inside UAV networks. This method is based on both Lyapunov Krasovskii functional and dynamic behavior of Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). The proposed hybrid method considers, as a preliminary step, a statistical signature of the traffic exchanged in the network. By looking up this signature in a bank of signatures, it is possible to characterize the different anomalies that can be observed in UAV networks. Consequently, the different signatures that we can process, based on the different types of...

[hal-01852144] On the geodesic distance in shapes K-means clustering

Publications ENAC - Tuesday, 9 October 2018 - 18:44:03
Using Information Geometry tools, we represent landmarks of a complex shape as probability densities in a statistical manifold. Then, in the setting of shapes clustering through a K-means algorithm, we evaluate the discriminative power of two different shapes distances. The first, derived from Fisher-Rao metric, is related with the minimization of information in the Fisher sense and the other is derived from the Wasserstein distance which measures the minimal transportation cost.

[hal-01876486] The Cyclic Job Shop Problem with uncertain processing times

Publications ENAC - Tuesday, 9 October 2018 - 18:29:53
Most models for scheduling problems assume deterministic parameters. In contrast, real world scheduling problems are often subject to many sources of uncertainty, for example activities duration can decrease or increase, machines can break down, new activities can be incorporated, etc. In this paper, we focus on scheduling problems that are cyclic and where activity durations are affected by uncertainty. Indeed, the best solution for a deterministic problem can quickly become the worst one in the presence of uncertainties. In this paper, we consider the Cyclic Job Shop Problem (CJSP) where processing times are affected by uncertainty. Several studies were conducted on...

[hal-01887290] Synchronization of Traffic Flow and Sector Opening for Collaborative Demand and Capacity Balancing

Publications ENAC - Tuesday, 9 October 2018 - 17:57:43
This paper proposes a method to synchronize traffic flow optimization and sector opening scheduling, with the aim of achieving flexible demand and capacity balancing (DCB). Delay assignment, trajectory options and sector collapsing are used to manage the traffic demand, while sector opening schemes are to affect the airspace capacity. Mixed Integer Programming (MIP) model is built to incorporate these initiatives. Three model variants are presented to illustrate the synchronization process, and their results in a real-world case study demonstrate some promising improvements for the DCB performances. Index Terms-air traffic flow management, trajectory options, dynamic...

[hal-01888558] Interval Observers for Secure Estimation in Cyber-Physical Systems

Publications ENAC - Friday, 5 October 2018 - 20:57:05
Stealthy attacks on the sensors and actuators embedded in cyber-physical systems could hinder the safe operation of these systems if the state estimators monitoring them cannot detect such attacks in time. In this paper, we study stealthy attacks in the framework of interval observers. We consider two classes of attacks: when a malicious agent compromises the sensors and when it is able to alter the system's actuators. For each type of attack, we design a dedicated interval observer for the system's state and we construct bounds for the attack signal. We investigate the ability of such interval observer to provide accurate estimates when the system is under the attack....
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