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A Retrospective on DISPEED - Leveraging Heterogeneity in a Drone Swarm for IDS Execution
No full textInternational audienceSwarms of drones are gaining more and more autonomy and efficiency during their missions. However, security threats can disrupt their missions' progression. To overcome this problem, Network Intrusion Detection Systems ((N)IDS) are promising solutions to detect malicious behavior on network traffic. However, modern NIDS rely on resource-hungry machine learning techniques, that can be difficult to deploy on a swarm of drones. The goal of the DISPEED project is to leverage the heterogeneity (execution platforms, memory) of the drones composing a swarm to deploy NIDS. It is decomposed in two phases: (1) a characterization phase that consists in characterizing various IDS implementations on diverse embedded platforms, and (2) an IDS implementation mapping phase that seeks to develop selection strategies to choose the most relevant NIDS depending on the context. On the one hand, the characterization phase allowed us to identify 36 relevant IDS implementations on three different embedded platforms: a Raspberry Pi 4B, a Jetson Xavier, and a Pynq-Z2. On the other hand, the IDS implementation mapping phase allowed us to design both standalone and distributed strategies to choose the best NIDSs to deploy depending on the context. The results of the project have led to three publications in international conferences, and one publication in a journal
Controlling lightning with lasers
No full textInternational audienceLightning is one of nature's most extreme phenomena. As fascinating as it is destructive, it causes billions of euros worth of damage every year. The idea of using lasers to control lightning dates back to the 1970s, but it wasn't until 50 years later, with the European Laser Lightning Rod project, that it was demonstrated for the first time that powerful lasers could guide lightning over long distances
Normal form analysis of nonlinear oscillator equations with automated arbitrary order expansions
No full textInternational audienceArbitrary order expansions for the automatic reduction and solutions of nonlinear vibratory systems have been developed successfully within the realm of the direct parametrisation of invariant manifolds. Whereas the method has been used with high-order expansions and large dimensional systems, this article proposes to look at the same problem from the opposite point of view. By using low-dimensionalsystems, symbolic computations, analytical developments and numerical verifications, this contribution analyses the reduced dynamics appearing in cases where a single master mode is involved, reviewing typical scenarios in nonlinear vibrations: primary resonance, sub- and superharmonic resonances and parametric excitation. To achieve this task, the normal form style is preferentially used. A symbolic open-source package is also provided to generalise the presented results to other styles, higher orders, and different scenarios. It is shown how the low-order terms allow recovering the classical solutions given by perturbation methods, and how the automated expansions allow one to generalise the analysis to arbitrary orders. When analytical solutions are not tractable anymore, numerical solutions are employed to underline how converged solutions are at hand when the validity limit of the expansions is not reached. All the results presented in this paper can thus be used to better understand the nonlinear dynamical solutions occurring in nonlinear vibrations, as well as from a system identification perspective, since the normal form is the simplest dynamical system displaying a given resonance scenario
War on JITs: Software-Based Attacks and Hybrid Defenses for JIT Compilers - A Comprehensive Survey
No full textInternational audienceProgramming Language Virtual Machines (VMs) are composed of several components that together execute and manage languages efficiently. They are deployed in virtually all computing systems through modern web browsers. However, vulnerabilities in any VM component pose a significant threat to security and privacy. In this paper, we present a survey of software attacks on Just-In-Time (JIT) compilers, which dynamically produce optimized code at run time. We first present an overview and categorization of software attacks and their vectors as presented in the literature, identifying three main attack classes: code injection, code-reuse and data-only attacks. We show how each can lead to arbitrary code execution. Next, we present a comprehensive taxonomy of defenses, including diversification, strict memory permissions and capability containment. While some were integrated in modern VMs, we draw recommendations for future protections. Securing JIT compilers remains challenging due to inherent conflicts with security principles, such as WX ( W ritable XOR e X ecutable), and the complexity of JIT optimizations. Finally, we examine how newer architectures, like ARMv8 and RISC-V, face similar threats. With RISC-V’s open architecture offering a promising platform for prototyping VM-specific protections and custom security instructions, we discuss hardware-assisted runtime protections and RISC-V extensions that could enhance VM security
Experimental Validation of a Model-Free Controller on a One-Axis Float with Ballast
No full textInternational audienceA large proportion of underwater vehicles use a ballast or a bladder for depth control. This is notably the case for most gliders and a variety of drifters, buoys, and floats used in oceanography, marine biology, etc. Their regulation in depth usually requires good knowledge of their model and is subject to external disturbances. This work presents the application of Model-Free Control (MFC) to a one-axis float equipped only with a ballast and a depth sensor. MFC is well-suited for this application as it is completely model-oblivious and particularly robust to external disturbances. The two main contributions of this work are the first development of a third-order model-free controller and the experimental validation of the method on a fairly simple system with minimum actuation, the float with ballast. The main objective of this work is to put MFC on the map of control methods suited for marine applications and introduce this method to the community with a rather simple yet striking example
Evaluating the YellowScan Navigator Topo-Bathymetric Lidar against IHO S44 Standards
No full textInternational audienceAs part of a student project, the Shom and ENSTA Bretagne had the opportunity to implement and evaluate the performance of the YellowScan Navigator Topo-Bathymetric Lidar. The YellowScan Navigator Lidar is a system that operates at a wavelength of 532 nm. One of its standout features is its ultra-lightweight design, weighing less than 5 kg, which allows for rapid deployment using a drone weighing under 25 kg. The primary objective of this project was to assess the system's compliance with the International Hydrographic Organization's (IHO) S44 standards.To achieve this, the system was deployed in two distinct environments: a freshwater quarry and along the Brittany coast. The freshwater quarry provided a controlled environment to assess the Lidar's precision and accuracy. The Brittany coast offered an open sea scenario to test the system's robustness and adaptability. The Flight plans were designed to evaluate the system's relative and absolute uncertainties, as well as its repeatability. Performance evaluations were conducted using ground truth data obtained through topographic poles and multibeam echo sounders. Additionally, a 1m x 1m cube was submerged to test the system's detection capabilities.The results of this project are expected to provide valuable insights into the capabilities and limitations of the YellowScan Navigator Lidar. This evaluation is crucial for understanding how such advanced technologies can be integrated into hydro graphic surveying practices
Real-Time Guaranteed Monitoring for a Drone Using Interval Analysis and Signal Temporal Logic
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: UNDERSTANDING INNOVATION IN INDUSTRY TO THINK ABOUT ENGINEERING SCHOOL TRAINING
No full textInternational audienceDesigning a training program dedicated to innovation in engineering schools raises challenging questions.Our objective here is to understand the representations that 22 innovators have of their activity in order tobe able to model different archetypical categories of innovator. We conducted individual interviews to studytheir discourse, then we analyzed them in two stages, firstly, using Iramuteq software, and secondly,manually. We thus have identified three archetypical forms of innovative actors which show that there ismore than one path to becoming the leader of an innovative project. Based on this, we suggest a two-levelinnovation training program.Concevoir un programme de formation dédié à l’innovation fait débat dans les écoles d’ingénieurs. Notre objectif ici est de comprendre les représentations qu’ont 22 acteurs de l’innovation de leur activité afin de pouvoir modéliser différents archétypes d’innovateur. Dans ce but, nous les avons interrogés sur leurs activités d’innovation, puis nous avons analysé leurs récits en deux étapes : via le logiciel Iramuteq premièrement, et de manière manuelle ensuite. Nous avons ainsi identifié trois archétypes d’acteurs de l’innovation qui montrent qu’il n’y a pas qu’une seule voie pour devenir porteur d’un projet innovant. À la suite de cela, nous proposons un programme de formation à l’innovation à deux niveaux
Physics of high-charge laser-plasma accelerators for few-MeV applications
No full textInternational audienceLaser-plasma accelerators represent a promising technology for future compact accelerating systems, enabling the acceleration of tens of pC to above 1GeV over just a few centimeters. Nonetheless, these devices currently lack the stability, beam quality, and average current of conventional systems. While many efforts have focused on improving acceleration stability and quality, little progress has been made in increasing the beam’s average current, which is essential for future laser-plasma-based applications, such as three-dimensional X-ray tomography for cargo inspection. In this paper, we investigate a laser-plasma acceleration regime aimed at increasing the beam average current with energies up to few MeVs, efficiently enhancing the beam charge. We present experimental results on configurations that allow reaching charges of 5–30 nC and a maximum conversion efficiency of around 14%. Through comprehensive particle-in-cell simulations, we interpret the experimental results and present a detailed study on electron dynamics. From our analysis, we show that most electrons are not trapped in a plasma wave; rather, they experience ponderomotive acceleration. Thus, we prove the laser pulse as the main driver of the particles’ energy gain process
Identification of a plasma actuated open-cavity under flow control
No full textInternational audienceThis paper addresses an input-output identification problem for a simulated incompressible open cavity flow. Despite the highly nonlinear and infinite-dimensional nature of the system, we look for a low complexity, linear, finite-dimensional model still capable of capturing the most salient features of the system. The inherent system instability, leading to the formation of its characteristic limit cycle, is a major obstacle in the application of classical identification schemes. To overcome such difficulty, we adopt a closed-loop identification method, which requires a preventive stabilization via an empirically designed controller. Being the controller perfectly known, an indirect approach is pursued. It consists of identifying the closed-loop transfer function and then reconstructing the unstable open-loop model by loop inversion. Extensive experiments led us to opt for a frequency domain identification based on an Output Error model structure. The identified model proves to be consistent with the infinite-dimensional one and, in particular, to reproduce its main instabilities.</div