Archives Ouvertes HAL
Toutes les publications de l'ENAC en direct.
All ENAC publications.
[hal-02159244] The geometry of the generalized gamma manifold and an application to medical imaging
The Fisher information metric provides parameterized probability densities with a Riemannian manifold structure, yielding the so-called information geometry. The information geometry of the gamma manifold associated to the family of gamma distributions has been well studied. However, only a few results are known for the generalized gamma family, that adds an extra shape parameter. The present article gives some new results about the generalized gamma 5manifold. This paper also introduces an application in medical imaging that is the classification of Alzheimer's disease population. In the medical field, over the past two decades, a growing number of quantitative image...
[hal-02156247] Antenne vectorielle large bande et à diversité de diagramme pour la radiogoniométrie 3D
Les performances d'estimation d'une antenne vectorielle sont améliorées en tirant profit de sa reconfi-gurabilité en diagramme. Une méthode est proposée afin de mettre à profit la diversité de diagramme pour estimer précisément la direction d'arrivée d'une onde électroma-gnétique.
[hal-02073283] Preconditioned P-ULA for Joint Deconvolution-Segmentation of Ultrasound Images - Extended Version
Joint deconvolution and segmentation of ultrasound images is a challenging problem in medical imaging. By adopting a hierarchical Bayesian model, we propose an accelerated Markov chain Monte Carlo scheme where the tissue reflectivity function is sampled thanks to a recently introduced proximal unadjusted Langevin algorithm. This new approach is combined with a forward-backward step and a preconditioning strategy to accelerate the convergence, and with a method based on the majorization-minimization principle to solve the inner non-convex minimization problems. As demonstrated in numerical experiments conducted on both simulated and in vivo ultrasound images, the proposed...
[hal-02149924] Software defined network based architecture to improve security in a swarm of drones
With the trend of developing more and more applications for Unmanned Aerial Vehicles (UAV), several research projects have considered new missions where single UAVs are replaced by swarms of drones. Although today regulations do not take into account such scenarios, implementation of an efficient security policy appears mandatory before operating a swarm of drones in open spaces. Consequently, this paper introduces an architecture for providing security features through the use of software defined network (SDN) technologies. To validate our approach, we compare the routing performance of our architecture with a classical solution based on the AODV routing protocol and...
[hal-02145644] Time-based Consensus
Reaching consensus is fundamental in distributed computing. For each execution of a consensus algorithm, there is no difference between the proposed values by different nodes with respect to their proposed times. By presenting a realistic application scenario related to distributed asynchronous mobile robots in dynamic environments, we argue some safety-critical, real-time systems require reaching consensus on the newest proposed values when the old proposed values may not be valid anymore. Afterward, we formulate a new type of consensus problem called time-based consensus, which requires to take into account the times of proposed values. Finally, to tackle such a...
[hal-02132979] A Continuum of Interfaces to Engage Surgical Staff in Efficient Collaboration
Large hospital surgical suites must combine high quality of care with an efficient management of operations. However, the diversity of procedures, staff, and patients present important challenges for staff collaboration. The complexity of flows between tasks and places, such as interconnections between pre-operation, post-operation and intensive care units, led previous research to address these issues separately using checklists, scheduling, or specialized human-computer interfaces. Approaches to treat the surgical suite as a whole entity have not been explored yet. Here, we build upon a cyber-physical system comprising an electronic whiteboard and different sensors...
[tel-02139581] Évitement de conflits aériens par une régulation subliminale en vitesse : modélisation & résolution via le contrôle optimal
À travers une approche de contrôle optimal, cette thèse de doctorat propose une étude des modèles et des techniques de résolution dans un domaine d'application propre à la gestion du trafic aérien. Motivés par la croissance des flux aériens d'une part, et les développements en théorie du contrôle optimal d'autre part, ces travaux portent sur l'analyse du problème d'évitement de conflits aériens. Cette étude permet le développement de nouvelles approches et algorithmes en vue d'aider les contrôleurs aériens dans leur tâche. Ainsi, dans le cadre du trafic aérien, afin de préserver des distances minimales de sécurité entre avions, lors de phases tactiques et de...
[hal-01722807] GPU based Computational Simulation of Aircraft Evacuation: Temporal and Spatial Analysis
he effectiveness of Aircraft Emergency Evacuation plays a vital role in the safety of the passengers on board an Aircraft, in case of Emergency landing. In this paper, the implementation and development of a Cellular Automata (CA) based simulator which can be used to simulate the Aircraft Evacuation process is presented. Given the seat-map of the Aircraft, number of passengers, passenger feature distribution and number of functional exits, the simulator can calculate the approximate time of Evacuation. For computational implementation, a bi-dimensional as well as uni-dimensional grid which represents the 2D Aircraft seat-map and an agent which control the passenger...
[hal-02138628] Pricing schemes for air traffic services through multi-level approaches
This article addresses the problem of air traffic service (ATS) pricing over a domestic air transportation system with either private or public ATS providers. In both cases, to take into account feedback effects on the air transportation market, it is considered that the adopted pricing approaches can be formulated through optimization problems where an imbedded optimization problem is concerned with the supply of air transportation (offered seat capacity and tariffs for each connection). Under mild assumptions in both situations the whole problem can be reformulated as a mathematical program with linear objective function and quadratic constraints. A numerical...