NCube/papyrus huggingface dataset:
Étude électrique et spectroscopique des décharges à barrière diélectrique à la pression atmosphérique en milieux réactifs

The work presented in this master’s thesis focuses on the study of atmospheric pressure plasmas in a dielectric barrier discharge (DBD) configuration, which are relevant for surface treatment. More specifically, the DBDs under study are in reactive media for the deposition of (multi)functional coatings, either in the presence of an organosilicon precursor (HMDSO) and/or an oxidizing agent (N₂O). The study focuses on the analysis of two fundamental plasma properties: the electron temperature (Tₑ) and the density of helium atoms in a metastable state (n_He(2³S)). The first is studied using measurements of the n = 3 level helium populations by optical emission spectroscopy, while the second is based on these same measurements coupled with electrical measurements. The peculiarity of this study is the development of new electrical and spectroscopic diagnoses to carry out spatially resolved measurements, that is depending on the residence time (t_res) of the gas mixture injected continuously. In the reactive media studied, these new diagnoses showed changes in the current-voltage characteristics between the entrance and the exit of the discharge. However, the Tₑ maintained a spatially homogeneous profile while the n_He(2³S) was relatively lower at entry, because of their interactions with the precursors and the impurities present in these media. The analysis of the HMDSO optical signatures in the discharge volume also made it possible to establish links with the surface properties of the coatings produced under similar conditions. In particular, the measurements of deposition rate observed on the coatings, being lower with the increase of the t_res, could be linked to the emissions of the carbonaceous fragments, stronger at the entrance, as well as to the n_He(2³S), weaker here, knowing that they play an important role in the fragmentation of the HMDSO precursor. Moreover, the analysis of emission intensity ratios of these fragments seems to show a similar trend to the O/C atomic ratios obtained by X-ray spectroscopy (XPS) measurements on the coatings produced, but the interpretation of these evolutions is more complex.

Keyphrases: DBD, Atmospheric pressure, Helium, Electronic temperature, Spectroscopy, Collisional-radiative model, Density of metastable atoms, Dielectric barrier discharge, Thin films, Coatings, Homogeneous discharge, Glow discharge, Local current measurement, Time resolved optical emission spectroscopy, Reactive media
Analyse d’étoiles naines blanches riches en hélium contaminées par des éléments lourds à l’ère Gaia

We present a homogeneous analysis of 1023 DZ and 319 DQ white dwarf stars taken from the Montreal White Dwarf Database. This represents a significant increase over the previous comprehensive studies on these types of objects, namely those of Dufour et al. (2005; 56 DQs) and Dufour et al. (2007; 159 DZs). We use new trigonometric parallax measurements from the Gaia second data release, together with photometry from the Sloan Digital Sky Survey, PanSTARRS, Gaia, or BVRI from the literature, which allow the determination of the mass for the majority of the objects in our sample. We use the photometric and spectroscopic techniques with the most recent atmosphere models available, which include high density effects, to accurately determine the effective temperature, surface gravity, and heavy element abundances for each object. We study the abundance of hydrogen in DZ white dwarfs and the properties of the accreted planetesimals. We find many white dwarfs dwarfs with progenitor masses above 3 solar mass, demonstrating that the formation of rocky material is not rare around this type of stars. We also present mass distributions for both spectral types. We explore the nature of the second sequence of DQ stars using proper motions from Gaia and discuss the possibility that it is a population of merged white dwarfs. We highlight evidence of crystallization in massive DQ stars.  Finally, we discuss the implications of our findings in the context of the spectral evolution of white dwarfs, and provide the atmospheric parameters for each star.

Keyphrases: Stars: fundamental parameters, Stars: evolution, White dwarfs
Complexité de Kolmogorov et corrélations quantiques; étude du carré magique

Quantum information, this intriguing marriage between computer science and physics, is a promising field of research for future technologies as well as a better understanding of our universe. Entanglement is at the very heart of this new way of understanding information. This thesis focuses on quantum correlations that are observed in nature. They have been studied in great detail by, among others, John Bell. More specifically, two non-signaling games, in which these correlations arise, are studied: the CHSH game, which is probably the best-known example of such games, and the magic square pseudotelepathy game. To do so, two points of view will be adopted: probabilistic and algorithmic. The first is motivated by prediction (what could have happened) and the second focuses on the intrinsic information about an object (what happened). Therefore, the concepts of randomness and information are first addressed from Shannon’s point of view (probabilistic approach) and second from Kolmogorov’s point of view (algorithmic approach). Kolmogorov complexity is used to quantify information in a factual way. Furthermore, the particular case in which multiple repetitions of a game are played in parallel in a classical world is considered. The parallel repetition theorem, an important result on the subject proven by Ran Raz, is presented and used in the algorithmic study of the CHSH game and the magic square game.

Keyphrases: Quantum correlations, Quantum information, Entanglement, Kolmogorov complexity, Parallel repetition theorem, Popescu-Rohrlich boxes, Magic square
L'enfant dans le projet pédagogique de Platon

This study wants to question Plato’s theory of soul through his conception of child and childhood. For this philosopher, human is a mixture of body and soul, which do not belong to the same domain. On the one hand, the body functions following the rules of the sensible world, which are temporal, corporeal and imperfect. On the other, the soul responds to the laws of the intelligible world which are eternal, transcendant and perfect. But the soul is confronted to the obstacles and the imperfections of the sensible world when it becomes the prisoner of a body. A human must try as best as he can to retrieve the perfection that his soul once possessed, especially through the practice of philosophy, which reminds him of what he was and therefore what he has to be. For Plato, the child suffers from a philosophical deficiency that complicates the return of the soul to perfection. He is completely dominated by his body and what his body provokes within his soul. Thus the child becomes a synonym of imperfection. As the first period of human life, childhood is the first obstacle that the soul must overcome to retrieve its true nature. This research would like to show that the child is a central subject of the Platonic system, because he becomes the fundamental stake of a philosophy whose goal is to achieve a better life for humans.

Keyphrases: Platon, Plato, Child, Childhood, Metaphysical, Theory of soul, Education
Conscience et intentionnalité : une évaluation critique des théories de l’intentionnalité phénoménale

Mental states can essentially have two types of properties: intentional properties, in virtue of which mental states have content, and phenomenal properties, in virtue of which mental states are consciously experienced. The instantiation of each of these two types of properties constitutes respectively what is called intentionality and phenomenal consciousness. A crucial question in contemporary philosophy of mind is to ask what the relationship between intentionality and phenomenal consciousness is. The phenomenal intentionality theories, which have gained popularity in recent years, argue that intentionality is fundamentally dependent on phenomenal consciousness. Since these theories now represent one of the main conceptions of intentionality available, it is crucial to assess their plausibility, which I propose to do in this master’s thesis. As I will try to show, intentional properties do not depend on phenomenal properties as understood by the advocates of the phenomenal intentionality theories. Indeed, the phenomenal intentionality theories are not able to explain one of the fundamental characteristics of intentionality, namely the fact that intentional states are accompanied by conditions of satisfaction, and that if they succeed in doing so, it is only by presupposing intentionality by assigning intentional characteristics to phenomenal states. This result forces us to turn to another conception of the relationship between intentionality and phenomenal consciousness.

Keyphrases: Perception, Phenomenal consciousness, Intentionality, Phenomenal intentionality, Content, Representation, Mind, Thought
La téléologie chez Spinoza

This paper examines the theme of the final causes in Spinoza’s Ethics (1677). Using a quadripartite classification of the types of discourse on the final causes, we define theological-metaphysical finalism as the main philosophical target of Spinoza’s critics. Radicalizing the epistemological Cartesian postulate according to which the divine will cannot serve as an explanatory principle for natural phenomena, Spinoza completely rejects the idea that the relationship between God and his creation can be conceived under the mode of the final cause and elaborates, in the shadow of this criticism, a conception of divine causality that presents the production of the world as a necessary result of God’s essence. Then, we briefly look at the concept of conatus, which is at the intersection of natural philosophy and ontology. We explore, according to three hypotheses, the possibility of teleological dynamics in nature. Finaly, the last part of our thesis tries to shed light on the articulation between, on the one hand, Spinoza’s natural philosophy and ontology and, on the other hand, his practical philosophy. We thus demonstrate the usefulness of using the final causes to explain human psychology and to account for the last station of the spinozist ethics, the beatitudo.

Keyphrases: Spinoza, Conatus, Modern philosophy, Natural philosophy, Teleology, Finality, Causality, Salvation
Les ressorts fictionnels au service du vrai : théorie et écriture romanesques dans l’oeuvre de Denis Diderot

This thesis, which deals with the interweaving of philosophy and literature in the work of French Enlightenment thinkers, seeks to shed light on Denis Diderot’s unique contributions to philosophical reflection on the novel, as well as to the exploration of the literary resources that make it possible to delve into philosophical issues through the novel. Beginning with an examination of Diderot’s explicit theories about writing narrative fiction, it argues that the outgrowth of his materialism and the disenchantment following his attempts at theatre reform upended the aesthetic and moral basis for the initial normative framework underpinning his analysis of how fiction is ideally written and received. It goes on to examine how Diderot, as a novelist, undertook an innovative and fruitful exploration of the unsuspected philosophical resources that narrative fiction offers. The final sections are devoted to a close reading of Jacques the Fatalist and His Master, beginning with an attempt to identify the main resources it deploys to train more lucid and critical readers of fiction. The thesis then seeks to show how this knowledge base, if successfully transmitted, ultimately leads the reader to engage in a genuine dialogue with the work, both in terms of the metaphysical and ontological issues raised by Jacques’ “fatalism” and the moral issues that ensue.

Keyphrases: Denis Diderot, XVIIIe siècle, Philosophy, Literature, French Enlightenment, Jacques the Fatalist and His Master, Philosophical novel, Materialism, Narrative self-reflexivity, 18th century
Perspectives pluralistes critiques sur l’indétermination du droit

No theory of the legitimacy of judges accompanies the Critical Legal Studies’ arguments on the indeterminacy of law, which entails there are no criteria to identify a legitimate interpretation. Critical legal pluralism, which redefines law to take account of its inherent plurality rather than denying its very possibility on these grounds, could however provide such criteria. Indeed, it presents many resemblances with Dworkin’s theory of law which argues that citizens are entitled to reap the benefits of the interpretative nature of law. Both theories defend that law allows to bridge a group’s past, which is essential to its self-understanding, with the present, and both insist that law must be made to appear relevant in the present.  Pluralists however prioritize the current significance of law and stress that communities are split by a variety of definitions of the good. According to them, law is mainly a process to think about human conduct and grant it meaning, and it depends as such on citizens’ creative capacities. Accordingly, only an interpretation that is accepted by a group and seen as meaningful can be considered legitimate. This criterion forces us to consider a form of negotiated justice, where two persons consult a judge to develop a common reading of a rule which would be legitimate in each person’s legal universe.

Keyphrases: Philosophy of law, Critical Legal Studies, Critical legal pluralism, Legal indeterminacy, Interpretivism, Legal meaning, Law and society, Alternative dispute resolution
Michel Foucault et l’heureuse coïncidence de la vérité : matériaux pour une critique de l’épistémologie foucaldienne

This research aims to circumscribe the epistemological foundation of the Foucauldian constructivism. More specifically, it tries to indicate his limits by challenging his internal consistency. In L’archéologie du savoir, Foucault develops a method to analyze the historical conditions of the possibility of knowledge, while putting aside the question of their conditions of legitimacy. The genealogic project, on the other hand, focuses on the social function of discourses, regardless of their epistemic validity. Therefore, the analyses of Foucault leaves, in both cases, the possibility of knowledge entirely open. However, the author sometimes seems to  adopt a nominalist position that radically jeopardizes this possibility. This work takes as its point of departure this apparent contradiction between the moderate constructivism on the basis of which is established the Foucauldian project and the linguistic idealism that Foucault defend at times. The aim is to evaluate if this tension can be solved by a clarification of the philosophical theses that underlie - in spite of their respective differences – the archeological and the genealogical project. This dissertation finally tries to show that any undertaking that would try to bring the philosophical foundations of the Foucauldian constructivism to their ultimate logical consequences necessarily hinges on serious aporias.

Keyphrases: Foucault, Savoir, Ideology, Knowledge, Constructivism, Postmodernism
Théorie idéale et théorie non idéale : analyse du contractualisme subversif de Charles Mills

In this thesis we will examine the debate between ideal theory and non-ideal theory. This is a debate that has already been much discussed, but new authors are constantly adding new arguments and new approaches. One of the authors who caught our attention is Charles Mills. We believe that he has made several interesting contributions to debates surrounding the relationship between ideal and non-ideal theory and specifically on the methodological aspect. In this study, we will focus on Mills criticisms of the methodology developed by Rawls and the political consequences of these problems. By relating Mills criticism not only to Rawls ideas, but also to contemporary debates, we will observe how his criticisms and his propositions answer certain problems that we can observe when we try to think of concrete actions from the ideal theory.

Keyphrases: Charles Mills, Racial justice, Ideal-theory, Non ideal-theory, Justice raciale, Rawls
Bornes sur les nombres de Betti pour les fonctions propres du Laplacien

In this thesis, we will work with the nodal sets of Laplace eigenfunctions on a few simple manifolds, like the sphere and the flat torus. We will obtain bounds on the total Betti number of the nodal set that depend on the corresponding eigenvalue. Our work generalize Courant's theorem.

Keyphrases: Ensemble nodal, Betti numbers, Eigenfunctions, Nodal set, Algebraic topology, Algebraic geometry
Extension de l'homomorphisme de Calabi aux cobordismes lagrangiens

In this master's thesis, we construct a new invariant of Lagrangian cobordisms. This construction is inspired by the recent works of Solomon in which an extension of the Calabi homomorphism to exact Lagrangian paths is given. Solomon's extension was motivated by the fact that the graph of any Hamiltonian isotopy is  an exact Lagrangian path. We use the Lagrangian suspension construction, which associates to every exact Lagrangian path a Lagrangian cobordism, to extend Solomon's invariant to Lagrangian cobordisms. In the first chapter, we give a brief introduction to the elementary properties of symplectic manifolds and their Lagrangian submanifolds. In the second chapter, we present an introduction to the group of Hamiltonian diffeomorphisms and discuss the fundamental properties of the Calabi homomorphism. Chapter 3 is dedicated to Lagrangian paths, Solomon's invariant and its critical points. In the last chapter, we introduce the notion of Lagrangian cobordism and we construct the new invariant. We analyze its critical points and evaluate it on the trace of the Lagrangian surgery of two curves on the torus. In this setting we further bound the new invariant in terms of the shadow of the cobordism, a notion recently introduced by Cornea and Shelukhin.

Keyphrases: Symplectic topology, Hamiltonian diffeomorphisms, Calabi homomorphism, Lagrangian paths, Lagrangian cobordism, Lagrangian surgery
Balancing signals for semi-supervised sequence learning

Recurrent Neural Networks(RNNs) are powerful models that have obtained outstanding achievements in many sequence learning tasks. Despite their accomplishments, RNN models still suffer with long sequences during training. It is because error propagate backwards from output to input layers carrying gradient signals, and with long input sequence, issues like vanishing and exploding gradients can arise. This thesis reviews many current studies and existing architectures designed to circumvent the long-term dependency problems in backpropagation through time (BPTT). Mainly, we focus on the method proposed by Trinh et al. (2018) which uses semi- supervised learning method to alleviate the long-term dependency problems in BPTT. Despite the good results Trinh et al. (2018)’s model achieved, we suggest that the model can be further improved with a more systematic way of balancing auxiliary signals. In this thesis, we present our paper – RNNs with Private and Shared Representations for Semi-Supervised Learning – which is currently under review for AAAI-2019. We propose a semi-supervised RNN architecture with explicitly designed private and shared representations that regulates the gradient flow from auxiliary task to main task.

Keyphrases: Auxiliary Learning, Deep Learning, Sequence Learning, Semi-supervised Learning, Machine Learning
Comparaison de systèmes de traduction automatique pour la post édition des alertes météorologique d'Environnement Canada

The purpose of this paper is to determine the strategy for the automatic translation of weather warnings produced by Environment Canada, which requires the least post-editing effort by the proofreaders of the Translation Bureau. We will begin by developing a bilingual corpus of weather warnings representative of this task. Then, this data will be used to compare the performance of different approaches of machine translation, translation memory configurations and hybrid systems. We will compare the results of these models with the system WATT, the latest system provided by RALI for Environment Canada, as well as with the industry systems GoogleTranslate and DeepL. Finaly, we will study an automatic post-edition system.

Keyphrases: Automatic translation, Machine learning, Weather warnings, Translation memory, Statistical machine translation, Neural machine translation
Unsupervised representation learning in interactive environments

Extracting a representation of all the high-level factors of an agent’s state from level-level sensory information is an important, but challenging task in machine learning. In this thesis, we will explore several unsupervised approaches for learning these state representations. We apply and analyze existing unsupervised representation learning methods in reinforcement learning environments, as well as contribute our own evaluation benchmark and our own novel state representation learning method.  In the first chapter, we will overview and motivate unsupervised representation learning for machine learning in general and for reinforcement learning. We will then introduce a relatively new subfield of representation learning: self-supervised learning.  We will then cover two core representation learning approaches, generative methods and discriminative methods. Specifically, we will focus on a collection of discriminative representation learning methods called contrastive unsupervised representation learning (CURL) methods. We will close the first chapter by detailing various approaches for evaluating the usefulness of representations.  In the second chapter, we will present a workshop paper, where we evaluate a handful of off-the-shelf self-supervised methods in reinforcement learning problems. We discover that the performance of these representations depends heavily on the dynamics and visual structure of the environment.  As such, we determine that  a more systematic study of environments and methods is required.   Our third chapter covers our second article, Unsupervised State Representation Learning in Atari, where we try to execute a more thorough study of representation learning methods in RL as motivated by the second chapter. To facilitate a more thorough evaluation of representations in RL we introduce a benchmark of 22 fully labelled Atari games. In addition, we choose the representation learning methods for comparison in a more systematic way by focusing on comparing generative methods with contrastive methods, instead of the less systematically chosen off-the-shelf methods from the second chapter. Finally, we introduce a new contrastive method, ST-DIM, which excels at the 22 Atari games.

Keyphrases: Deep learning, Unsupervised learning, Representation learning, Reinforcement learning, Self-supervised learning, Constrastive unsupervised representation learning