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Evaluating Students’ Experiences in Hybrid Learning Environments: A Comparative Analysis of Kubi and Double Telepresence Robots
No full textInternational audienceAmidst the Covid-19 pandemic, distance learning was employed on an unprecedented level. As the lockdown measures have eased, it has become a parallel option alongside traditional in-person learning. Nevertheless, the utilization of basic videoconferencing tools such as Zoom, Microsoft Teams, and Google Meet comes with a multitude of constraints that extend beyond technological aspects. These limitations are intricately linked with human behavior, psychology, but also pedagogy, drastically changing the interactions that take place during learning. Telepresence robots have been widely used due to their advantages in enhancing a sense of in-person. To investigate the opportunities, the impact, and the risks associated with the usage of telepresence robots in an educational context, we conducted an experiment in a real setting, in the specific use case of a design school and a project-based class. We are interested in the experience of a classroom and the relationships between a distance student, his/her peers, and the professor/instructor. This study employed two types of robots: a Kubi robot (a semi-static tablet-based system) and a Double robot (a mobile telepresence robot). The primary objective was to ascertain the perceptions and experiences of both remote and in-person students during their interaction with these robots. The results of the study demonstrate a marked preference among students for the Double robot over the Kubi, as indicated by their feedback
Study on the interaction between a projectile and the barrel: Application to cased telescoped technology
No full textInternational audienceMost standard ammunition begin its interior ballistics cycle in the barrel at the forcing cone, thus with a low velocity (a few m/s at most). However, it is not the case for some technologies such as telescoped ammunition (projectile entirely housed in the cartridge). In that case, the projectile begins its interior ballistics (IB) cycle inside the cartridge, arriving at the forcing cone with a non-negligible velocity (several hundreds of m/s). This specificity is not considered in classical interior ballistics models. The ensuing impact has then been studied analytically with two approaches (monodimensionnal shock wave and static engraving considerations), to propose a simple modification of the classical IB equations. Numerical simulations have also been conducted with a finite element software (ABAQUS) to study the influence of the friction coefficient on the velocity of a projectile impacting a forcing cone. The results show trends in agreement with experimental results
Contrôle optimal sous incertitudes pour l'atterrissage vertical d'un premier étage de lanceur réutilisable
No full textThe work in this thesis focuses on the development of a robust trajectory planning and optimal control method. It provides theoretical justifications for the method presented, proving the existence of solutions to the problem formulated. Finally, the method is applied to a trajectory planning problem for the vertical landing of a reusable launch vehicle first stage.Les travaux de cette thèse portent sur le développement d'une méthode robuste de planification de trajectoire et de contrôle optimal. Ils apportent des justifications théoriques à la méthode présentée, prouvant l'existence de solutions au problème formulé. Enfin, la méthode est appliquée à un problème de planification de trajectoire pour l'atterrissage vertical d'un premier étage de lanceur réutilisable. Les contributions proposées sont les suivantes
All-Optical Simultaneous Frequency Metamorphose Contingent on a Three Parallel SOA-MZIs Copula
No full textInternational audienceIn this treatise, we develop a standard modulation design to consummate concomitant frequency up mixing dependent on the three parallel SOA-MZIs by employing a sampling arrangement in Virtual Photonics Inc. (VPI) software. Each SOA-MZI is used to acquire a frequency output sampled signal at higher frequencies. Then, the amalgamation of these three mixed signals leads to a simultaneous up-conversion procedure. The peak and positive conversion gains (CGs) are compassed with the SOA-MZIs connected in parallel for frequency mixing for higher frequencies of data signals from 0.5 to 98 GHz, 1 to 98.5 GHz, and 1.5 to 99 GHz, concurrently, which are in connection with the control signal at the frequency of the fifth harmonic. Moreover, we assess the worth of the performance characterizations of the mixing system using orthogonal frequency division multiplexing (OFDM) complex modulated signals. This novel three parallel SOA-MZIs system is completed for the first time in order to achieve frequency transformation to higher frequencies. The numerically calculated CG, error vector magnitude (EVM), and bit error rate (BER) values are in exceptional concurrence with those procured through the VPI simulator. The upper bit rate that concurs the forward error correction (FEC) confines is 2 Gbit/s for OFDM modulations. The three parallel SOA-MZIs setup leads to well-recognized results and it is deemed as a superb system due to its good achievement. Subsequently, this system is analyzed in order to contrast with our previous systems based on a signal SOA-MZI and a cascaded SOA-MZIs link. Furthermore, this comparison shows that the three parallel SOA-MZIs system has perfect efficiency and quality
Scaling of Free Subduction on a Sphere
No full textInternational audienceBecause Earth's tectonic plates are doubly curved shells, their mechanical behavior during subduction can differ significantly from that of flat plates. We use the boundary-element method (BEM) to study free (gravity-driven) subduction in axisymmetric and 3-D geometry, with a focus on determining the dimensionless parameters that control the dynamics. The axisymmetric model comprises a shell with thickness and viscosity subducting in an isoviscous planet with radius and viscosity . The angular radius of the trench is . Scaling analysis based on thin-shelltheory reveals two key dimensionless parameters: a `flexural stiffness' that is also relevant for flat plates, and a new `dynamical sphericity number' that is unique to spherical geometry.Here is the `bending length', or the sum of the lengths of the slab and of the seaward flexural bulge. The definition of implies that the dynamical effect of sphericity is greater for small plates than for large ones; we call this the `sphericity paradox'. By contrast, the purely geometric effect of sphericity is opposite, i.e. greater for large plates than for small ones. The dynamical and geometrical effects together imply that sphericity significantly influences subduction at all length scales. We confirm the scaling analysis using BEM numerical solutions, which show that the influence of sphericity on the slab sinking speed (up to a few tens of percent) and on the hoop stress (up to a factor of 2-3) are largest for small plates such as the Juan de Fuca, Cocos and Philippine Sea plates. We next study a 3-D model comprising a plate bounded by a ridge and a semicircular trench subducting in a three-layer earth consisting of an upper mantle, a lower mantle and an inviscid core. We examine the linear stability of the shell to longitudinal perturbations corresponding to buckling, and determinea scaling law for the most unstable wavelength that we compare with the observed shapes of northern/western Pacific trenches
Objective characterisation of corneal transparency by analysis of clinical SD-OCT images
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Augmenting Autotelic Agents with Large Language Models
No full textInternational audienceHumans learn to master open-ended repertoires of skills by imagining and practicing their own goals. This autotelic learning process, literally the pursuit of self-generated (auto) goals (telos), becomes more and more open-ended as the goals become more diverse, abstract and creative. The resulting exploration of the space of possible skills is supported by an inter-individual exploration: goal representations are culturally evolved and transmitted across individuals, in particular using language. Current artificial agents mostly rely on predefined goal representations corresponding to goal spaces that are either bounded (e.g. list of instructions), or unbounded (e.g. the space of possible visual inputs) but are rarely endowed with the ability to reshape their goal representations, to form new abstractions or to imagine creative goals. In this paper, we introduce a language model augmented autotelic agent (LMA3) that leverages a pretrained language model (LM) to support the representation, generation and learning of diverse, abstract, human-relevant goals. The LM is used as an imperfect model of human cultural transmission; an attempt to capture aspects of humans' common-sense, intuitive physics and overall interests. Specifically, it supports three key components of the autotelic architecture: 1) a relabeler that describes the goals achieved in the agent's trajectories, 2) a goal generator that suggests new high-level goals along with their decomposition into subgoals the agent already masters, and 3) reward functions for each of these goals. Without relying on any hand-coded goal representations, reward functions or curriculum, we show that LMA3 agents learn to master a large diversity of skills in a task-agnostic text-based environment
Evidence of coherence in strong-field electron photoemission from a semiconductor
No full textStrong-field quantum electronics is emerging as a potential candidate in information processing but still coherence vs decoherence is a primary concern of the concept. Strong-field coherent processes in band gap materials have led during the last decade to the emergence of high harmonic generation in semiconductors, petahertz electronics, or strong-field quantum states. However, the coherent behavior of the sub-optical cycle-driven electrons has never been directly observed. We report here on the experimental evidence of coherent ultrashort emission of hot electrons from a nanostructured semiconductor. Our method uses sub-wavelength electric field enhancement to localize the electron emission within a nanometer-scale spot. We found similarities with the electron emission from metallic nanotips in the strong-field regime, a topic that has opened a vast domain of applications during the last decade. The electron spectra display both odd and even harmonic orders of the driving femtosecond laser frequency, a signature of the coherent nature of the electron emission and their attosecond timing. Our findings complete our knowledge of phenomena governing coherent strong-field processes in semiconductors and open perspectives for the generation of future quantum devices operating in the strong-field regime
Approche par blocs du filtrage des signaux piloté par les données
No full textInternational audienceThe aim of this work is the signals filtering by a data driven approach, namely the empirical mode decomposition (EMD). The filtered signal est estimated by the partial reconstruction of a reduced number of sifted empirical modes (IMFs) using an energetic criterion, the Consecutive MSE (CMSE). This CMSE-based filtering, largely used in the literature of the domain, is a simple way to estimate signals of interest embedded in noise. However, this strategy is a global one and thus informative events such as fine details or short events are not well reconstructed at the expense of large structures of the signal of interest. To improve the performances of the filtering, a local filtering version is proposed where CMSE strategy is applied block wise. Simulation results are presented and compared to those of wavelet-based approach.Dans cet article on s'intéresse au problème du filtrage des signaux par une méthode pilotée par les données, à savoir la décomposition modale empirique (EMD). Le signal filtré est obtenu par une reconstruction partielle des modes empiriques (IMFs) extraits par l'EMD et ce en utilisant un critère énergétique mesurant l'écart quadratique moyen entre deux reconstructions consécutives, le CMSE (Consecutive MSE). L'approche CMSE, largement utilisée dans la littérature du domaine, fournit un moyen simple pour estimer des signaux, en présence de bruit. Cela étant, ce filtrage est global. Ainsi, pour les signaux d'intérêt caractérisés, par exemple, par des détails fins, des événements courts ou peu contrastés (non stationnaires) cette approche a tendance à mal les reconstruire au détriment des grandes structures du signal informatif. On propose dans cet article, une approche locale ou par blocs de la méthode CMSE qui permet d'améliorer les performances de la reconstruction du signal d'intérêt. Des résultats de simulation sont présentés et comparés à ceux de l'approche par ondelettes
Where There is Weirdness, Critique has Not Run Out of Steam: On Weird Literature, Pragmatist Ecology, and Democracy
No full textInternational audienceEcologists are now terrified. They are afraid of the ghosts of the Anthropocene, the memories of thingsdisplaced. They are anguished by the new beings that seem to be popping up everywhere, disrupting theirestablished sense of the order of things. But perhaps most of all, they are afraid that others are possessed bydangerous ontological spirits. Dualists have become existential monstrosities. Liberals are now a lusus naturae.The vestiges of modernity—so Latour—demand “exorcism”. For thinkers such as these, the Anthropoceneordinary is a one with the world of horror fiction. They are not cool-headed narrators. Their desire to dis-enchantthe world has made them see others as possessed. Delirious they are as they go on and on about the dangers ofdualisms in texts that are themselves dualistic. Ecological thinking needs to get a hold on horror. It needs toreflect on what is really horrifying to avoid making war on made up monsters, or—which would be worse—senselessly torturing innocents or potential allies as witches. Like puritanism before it, ecological thinking needsto get pragmatic.But even pragmatists feel fear. They also fall back into metaphysical fantasies. They do this, because theyperfectly well know that the real horror is the human susceptibility to the myth of the given, the fact that—in thewords of Emerson—"the world I converse with in the city and in the farms, is not the world I think” , and gettingthese two worlds right—exactly, and not pragmatically, right—seems to matter more than ever in theAnthropocene. But does it? And is attaining such a cosmic synthesis really a rational pragmatic expectation, or isit only, as we have accepted since Kant, but a disfunction of reason? After all, why should the capacities ofreason ally anything stand in exception to the entropy of the cosmos? No reason at all. And yet where there is nohope, there may be understanding of our fear and its promptings towards metaphysics. Where there is no wayout, there may too be therapies.Pragmatism, like the eco-weird, is a child of Transcendentalism. The two are twins: the narrative transcendencesof the weird making manifest what happens when affect pushes pragmatism to its limits. But the weird, and inparticular the eco-weird, is also a cure for pragmatism, a means that pragmatists can use to push back, to gettheir horror, and their metaphysics, into perspective, and so to rationally confront the horrors of theAnthropocene, attending to what matters, which is not the exorcism of other ways of viewing the world, but thepractical task of struggling for realism with our own limited minds and languages.Or so this intervention will argue via its double exposition of the horrors of ecology, and the pragmatic spiritualpractice of reading the eco-weird for the plane