Archives Ouvertes HAL
Toutes les publications de l'ENAC en direct.
All ENAC publications.
[hal-03665747] A Dual-Band Hollow Dielectric Resonator Antenna for GPS Applications
This work presents a dual-band hollow rectangular dielectric resonator antenna (DRA) fed by a single coaxial probe, which is designed to operate at the L5 and L1 bands for Global Positioning System (GPS) applications. The dimensions of the dielectric resonator are designed so that each one of its fundamental modes TE x δ11 and TE y 1δ1 resonates at the L5 and L1 bands, respectively. However, the higher-mode TE x δ21 may appear at the upper band and, thus, disturbing the radiation characteristics of the TE x δ11 mode. To overcome this situation, an air gap is introduced into the DRA to shift this mode away from the L1 band. Also, the reflection coefficient and radiation...
[hal-03668033] A Lightweight Fluid Model for Mobile Ad hoc Distributed Systems
Emerging edge applications introduced new computing timevariant topologies with mobile nodes connected via ad hoc networks. Such topologies are fundamentally different from cloud infrastructures due to the lack of hierarchy and clear network function separation. Sometimes, nodes that are sources are also destinations and routers, hence, creating dynamic flow patterns traversing the network. The latter, thus, can change the average performance of a distributed system, such as throughput and latency. This work introduces an analytical model based on fluid quantities to study data flows of distributed systems in mobile ad hoc networks. Using an approach based on a network of...
[hal-03668711] Attention Networks for Time Series Regression and Application to Congestion Control
This paper studies a new attention-based recurrent architecture, lighter and less computationally expensive than a global attention network. This type of architecture achieves better performance than commonly used recurrent networks for time series regression. An application to congestion control is considered, where the history of round trip times (RTT) evolution history is used to monitor congestion control. The performance of the proposed new congestion control strategy is evaluated with both synthetic and real traces, showing that it can be efficiently used to estimate the congestion state of a network.
[hal-03667323] Statistical Analysis of Aircraft Trajectories in a Multivariate Functional Data Analysis Framework
While advanced inference and registration methods for functional data analysis have recently been developed in the literature, statistical analyses of aircraft trajectories have remained scarce, despite operational relevance. Using more than 3,000 trajectories matched with weather data, this paper explores how the experienced wind speed can be associated to en-route delays in a multivariate functional data analysis framework. The processing of aircraft trajectories is challenging as it requires constraint smoothing and rescaling. The paper emphasizes that the choice of the registration strategy influences further inference. Five scenarios are developed to compare...
[hal-03655570] NON DEGENERACY OF AFFINELIKE LIE ALGEBRA
The aim of this note is to prove some cohomological vanishing theorems for non solvable affinelike Lie algebras, say ALLA. There are some relevant consequences of our vanishing theorems: (1) Every real non solvable affinelike Lie algebra is formally nondegenerate in the sense of A. Weinstein, (Theorem 1.1). (2) Let G be a non solvable Lie group whose Lie algebra is an affinelike Lie algebra (g,e). If the radical of [ker(ad(e)),ker(ad(e))] is commutative, then G admits a left invariant symplectic structure if and only if it has an open coadjoint orbit, (Theorem 1.2). (a) In Section 6, we use our vanishing theorems to supply an algebraic proof of the normal form theorem for...
[hal-03663984] Successive Convexification for Optimal Control with Signal Temporal Logic Specifications
As the scope and complexity of modern cyber-physical systems increase, newer and more challenging mission requirements will be imposed on the optimal control of the underlying unmanned systems. This paper proposes a solution to handle complex temporal requirements formalized in Signal Temporal Logic (STL) specifications within the Successive Convexification (SCvx) algorithmic framework. This SCvx-STL solution method consists of four steps: 1) Express the STL specifications using their robust semantics as state constraints. 2) Introduce new auxiliary state variables to transform these state constraints as system dynamics, by exploiting the recursively defined structure of...
[hal-03660605] Interactive trajectory modification and generation with FPCA
Moving object analysis is a constantly growing field with numerous concrete applications in terms of traffic understanding, prediction and simulation. While many algorithms and analytic processes exist, there are still areas of investigation with novel trajectory analysis methods. As such, the geometric information analyses data with respect to its statistical distribution along extracted dimensions. This opens new ways of gaining a better understanding of large and complex trajectory data sets while providing flexible data manipulations. In this paper, we report our investigations with the development of an interactive methodology based on the geometric information...
[hal-03664170] An Efficient Summation Algorithm for the Accuracy, Convergence and Reproducibility of Parallel Numerical Methods
Nowadays, parallel computing is ubiquitous in several application fields, both in engineering and science. The computations rely on the floating-point arithmetic specified by the IEEE754 Standard. In this context, an elementary brick of computation, used everywhere, is the sum of a sequence of numbers. This sum is subject to many numerical errors in floating-point arithmetic. To alleviate this issue, we have introduced a new parallel algorithm for summing a sequence of floating-point numbers. This algorithm which scales up easily with the number of processors, adds numbers of the same exponents first. In this article, our main contribution is an extensive analysis of its...
[hal-03653339] CandyFly: Bringing fun to drone pilots with disabilities through adapted and adaptable interactions
Flying drones is an increasingly popular activity. However, it is challenging due to the required perceptual and motor skills for following and stabilizing the drone, especially for people with special needs. This paper describes CandyFly, an application supporting people with diverse sensory, cognitive and motor impairments to pilot drones. We observed an existing accessible piloting workshop and evaluated CandyFly during eight additional workshops over three and a half years using a research-through-design process and ability-based design methods. We identified users' needs, formulated requirements and explored adaptive interactions such as using pressure-sensitive keys...