NCube/papyrus huggingface dataset:
Décoder la localisation de l'attention visuelle spatiale grâce au signal EEG

Visuospatial attention can be deployed to different locations in space independently of ocular fixation, and studies have shown that event-related potential (ERP) components can effectively index whether such covert visuospatial attention is deployed to the left or right visual field. However, it is not clear whether we may obtain a more precise spatial localization of the focus of attention based on the EEG signals during central fixation. In this study, we used a modified Posner cueing task with an endogenous cue to determine the degree to which information in the EEG signal can be used to track visual spatial attention in presentation sequences lasting 200 ms. We used a machine learning classification method to evaluate how well EEG signals discriminate between four different locations of the focus of attention. We then used a multi-class support vector machine (SVM) and a leave-one-out cross-validation framework to evaluate the decoding accuracy (DA). We found that ERP-based features from occipital and parietal regions showed a statistically significant valid prediction of the location of the focus of visuospatial attention (DA = 57%, p < .001, chance-level 25%). The mean distance between the predicted and the true focus of attention was 0.62 letter positions, which represented a mean error of 0.55 degrees of visual angle. In addition, ERP responses also successfully predicted whether spatial attention was allocated or not to a given location with an accuracy of 79% (p < .001). These findings are discussed in terms of their implications for visuospatial attention decoding and future paths for research are proposed.

Keyphrases: EEG, Classification de signal, Visual spatial attention, Event-related potential, Brai, Signal classification, Support vector machine
Le décodage des expressions faciales émotionnelles à travers différentes bandes de fréquences spatiales et ses interactions avec l’anxiété

The decoding of emotional facial expressions (EFE) is a key function of the human visual system since it lays at the basis of non-verbal communication that allows social interactions. Numerous studies suggests that the processing of faces diagnostic features may take place differently for low and high spatial frequencies (SF), respectively in the magno- and parvocellular pathways. Moreover, conditions such as social anxiety are supposed to influence this processing and the associated event-related potentials (ERP). This study explores the feasibility of predicting social anxiety levels using electrophysiological correlates of EFE processing across various SF bands. To this end, ERP from 26 participants (mean age = 23.7 ± 4.7) years old were recorded during visual presentation of neutral, angry and happy facial expressions, filtered to retain only low, medium or high SF. Social anxiety was previously assessed using the LSAS questionnary. Peak latencies and amplitudes of the P100, N170, N2b/P3a complex and P3b components were statistically analyzed and used to feed supervised machine learning algorithms. P100 amplitude was linked to SF content. N170 was effected by EFE. N2b/P3a complex was larger for EFE and earlier for high SF. P3b was lower for neutral faces, which were also more often omitted. The linear discriminant analysis showed a decoding accuracy across significant features with a mean of 56.11%. The nature of these features and their sensitivity to social anxiety will be discussed.

Keyphrases: Emotional facial expressions, Spatial frequencies, Electroencephalography, Event-related potentials, Machine learning, Linear discriminant analysis, Social anxiety
Mesurer les habiletés de la population générale à percevoir et à se synchroniser à la pulsation musicale avec le Montreal – Beat Alignment Test (M-BAT)

There are currently many tests to measure the abilities to perceive the beat in music and to synchronize its movements with it. These tests, however, have certain methodological shortcomings (long duration of administration, different stimuli between sub-tests, mismatch conditions). The Montreal-Beat Alignment Test (M-BAT) has been developed to overcome these deficiencies and provide a simple and sensitive measurement of these skills. A sensitivity study was conducted with 90 participants. For the task of perception, we see a distribution with a slight negative asymmetry and without the presence of floor or ceiling effect. The performances for the perception and synchronization tasks are moderately correlated, suggesting that a good perception of the pulse is usually accompanied by a good ability to synchronize with it. Also, case deficits in one and/or the other of these skills are reported, indicating the presence of dissociations between perception and synchronization with the musical beat.

Keyphrases: Beat perception, synchronization, impairment, perception
Stratégies de résolution de conflits conjugaux et compétence sociale de l'enfant à l'âge préscolaire : l'effet modérateur du sexe de l'enfant

In couples, conflict is often viewed negatively and affecting the quality of the relationship and children's adjustment. On the other hand, not all conflicts are negative. Indeed, in a context where parents use positive resolution strategies, conflicts can become a learning environment for young children and allow them to reuse these models to be more socially competent. This study aims to evaluate the relationship between marital conflict resolution strategies and the social competence of preschool children depending on the sex of the parent and the child's sex. Data were collected from 160 families with a child aged between 4 and 6 years old. This is a transversal research design. Results show marital conflict resolution strategies are marginally related to the level of social competence of the children, but only for the fathers. In addition, children's gender marginally moderate this relation, boys being more socially competent when more exposed to a high ratio of positive resolution strategies from their fathers. A significant difference was observed between boys and girls as to their level of social competence, girls being more competent socially than boys.

Keyphrases: marital conflict resolution strategies, marital conflict, preschool aged, social competence, social learning, emotional security, differences between genders
Implantation d’une sonde d’absorption photo-induite dans une expérience de spectroscopie bidimensionnelle d’excitation sur le système polymérique modèle PCDBT:PCBM

This master’s thesis present the implemantation of a photo-induced absorption probe to a collinear phase modulated two-dimensionnal excitation spectroscopy experiment. This type of spectroscopy studies the correlations between different elctronic states of a material on an ultrafast timescale to know better about the system’s dynamics. This new probe, combined to this experiment gives insight on materials where a coupling prevents from understandin the dynamic of the system. If there is such coupling between two states, it is impossible to probe the relaxation directly with light. Studying the correlations between the states, is it possible to learn more about this coupling. To prove that this new technique brings valid information on a studied material, we want to compare the results obtained with the photoinduced absorption probe to those obtained with a photoluminescence one for a system where we expect these results to be the same, PCDTBT:PCBM. Since the two-dimensionnal spectroscopy experiment enlightens the correlations between the excited states and the final products, if we probe the same final products with different probes, we should obtain the same results. Even though it was impossible to compare the results with the photoluminescence probe since the emitted signal was too low to be detected, the validity of the new probe was shown by comparing with data already known in the litterature and by making sure that the sample’s response was linear when it was expected to be. Also, the signal obtained with the new probe came from the excited states of the PCDTBT:PCBM, hence of the absorption. Finally, these results were compared to the ones obtained by a photocurrent probe. The quantum efficiency of the obtained results by the both probes was almost identical, proving the validity of this new probe to study correlations in different materials.

Keyphrases: PCDTBT:PCBM, Photoluminescence, Non-linear spectroscopy, Photo-induced absorption, Linearity
Modulation du spectre infrarouge du graphène

Graphene is a promising nanomaterials thanks to its excellent mechanical, optical and electrical properties. However, its most innovative applications require that it be altered, but the understanding altered graphene is still limited.  Some applications are considered in infrared optics. However, our current understanding of graphene does not explain the appearance of the infrared peaks that are observed in bilayers and grafted monolayers. The behaviour of grafted graphene is especially baffling, since the addition of grafts makes it more transparent, not less!  A model proposed by Bruno Rousseau, a postdoctoral student of Professor Michel Côté at Université de Montréal, suggests an explanation for this phenomenon: although the phonons of graphene cannot couple directly with light, they could couple indirectly through collisions with the electrons, which can couple with photons. This indirect coupling may produce constructive and destructive interference, depending on the conditions, so this mechanism can produce absorbance peaks as much as transparency peaks.  In this master’s thesis, we have undertaken to experimentally verify the validity of this model, and we conclude that it seems to adequately predict the behaviour of the infrared activity of graphene bilayers and grafted monolayers. We also studied the methods by which we synthesized these different types of graphene to optimize them. Finally, we determined techniques based on Raman spectroscopy to characterize the intensity of the alteration induced by these methods.

Keyphrases: Twisted bilayer graphene, Grafted graphene, Infrared spectroscopy, Raman spectroscopy, Drude model, Fano resonance
Étude des conditions d'extinction d'un système prédateur-proie généralisé avec récolte contrôlée

In this master thesis, we study a generalized Gause predator-prey system with controlled prey harvest and a generalized Holling response function of type III. We introduce a controlled prey harvesting function taking into account the number of preys with a harvesting threshold. This makes the system realistic, it optimizes the harvesting, and it prevents the possibility of species' extinction which exists in the system with constant harvest for all parameters. This type of harvesting function a priori implies handling a discontinuous system : therefore we study smoothing techniques of such discontinuities by regularization. We first return on systems without and with constant harvest by drawing the exact bifurcation diagrams and phase portraits of those systems. Then, we study the discontinuous system and the regularization methods in order to choose the optimal one. Finally, we put together everything by studying the regularized prey harvesting system through a complete study of the prey stocking system, and we highlight the different effects on the phase portraits under the initial conditions.

Keyphrases: Cycles limites, Controlled harvesting, Discontinuous dynamical system, Regularization, Hoft bifurcation, Heteroclinic bifurcation, Limit cycles, Prey stocking
Fibrés symplectiques et la géométrie des difféomorphismes hamiltoniens

This thesis presents a reasonably complete account of the elements theory of symplectic and Hamiltonian fibrations.  We assume a familiarity and comfort with the basic notions of differential geometry and algebraic topology but little else.  Proceeding from this, the first chapter develops the necessary notions from the theory of fiber bundles and G-fiber bundles, while the second chapter develops all the notions and theorems required to understand the later theory of symplectic fibrations.  Most notably the second chapter includes a detailed account of the classical relationship between the flux homomorphism and Hamiltonian isotopies.  The third chapter is where we develop the theory of symplectic and locally Hamiltonian fiber bundles, and in particular give an invariant construction of the coupling form on a symplectic fibration admitting an extension class.  the third chapter ends with a proof of a structure theorem characterizing those symplectic fibrations for which the structure group reduces to the Hamiltonian group.  In the final chapter, we present some applications of the theory of Hamiltonian fibrations by the way of characterizing the positive part of the Hofer norm of a Hamiltonian loop as the K-area of its associated Hamiltonian bundle over the sphere, and we finish by giving a proof of the non-degeneracy of the Hofer norm for closed symplectic manifolds.

Keyphrases: G-fiber bundles, Symplectic fiber bundles, Hamiltonian fiber bundles, Flux morphism, Hofer norm, K-area, Coupling form
Enseignement de la traductologie au Brésil : étude ethnographique à l'Universidade Federal de Santa Catarina (UFSC)

Brazil is a country which attracts the attention of the whole world. Indeed, specialists from all fields are fascinated by this emerging country. The situation is not different when it comes to Translation Studies. Brazil captivates the attention of Translation scholars worldwide, who are interested in the dynamism of its translation practices and theoretical reflection on translation. The objective of this thesis is to draw an overall picture of Translation Studies teaching in Brazil, more particularly in the Pós-Graduação em Estudos da Tradução (PGET) of the Universidade Federal de Santa Catarina (UFSC). This program, established in 2003, is the first specialized programme in Translation Studies in Brazil, and the first PhD in Translation Studies in Latin America. In 2016, there are about 200 students who are registered at Master’s degree and PhD level in the PGET. After an overview of different theories on translation teaching and learning, we describe the main publications in Translation Studies teaching. That description reveals that Translation Studies teaching is still a rather under-exploited field. Our interest in Brazil has been motivated by the fact that it has an important number of students specializing in Translation Studies, which is above the world average. We start by going through the history of translation teaching since 1968, date of creation of the first Translation program in the Pontifícia Universidade Católica do Rio de Janeiro. We then engage in the history and the structure of the UFSC’s PGET, our main subject of study. Using an ethnographic field study, we describe the main features of the teaching of Translation Studies at the PGET/UFSC, the general profile of its students and teachers, the subjects taught and the teachers’ teaching methodologies.

Keyphrases: Brazil, Translation Studies, Translation Teaching, Postgraduate Studies in Translation
Implémentation des collocations pour la réalisation de texte multilingue

Natural Language Generation (NLG) produces text in natural language from non-linguistic content. NLG aims at developing generators that are reusable across languages and applications. In order to do so, these systems’ architecture is modular: while the deep generation module determines the content of the message to be expressed, the text realization module maps the message into its most appropriate linguistic form. Multilingual text realization requires to model the core linguistic phenomena that one finds in language. Collocations represent one of the core linguistic phenomena that remain problematic not only in NLG, but also in Natural Language Processing in general. The Meaning-Text theory analyses collocations as constraints on lexical selection. In other words, a collocation is made up of three constituents: (i) the base, (ii) the collocate, chosen according to (iii) a semantico-lexical relation. Some of these semantico-lexical relations are systematic and shared by many collocations. Lexical functions are a system for modeling these relations. In fact, collocations such as heavy rain or strong preference instantiate the same relation, intensity, can be described with the lexical function Magn: Magn(RAIN) = HEAVY, Magn(PREFERENCE) = STRONG, etc. There are hundreds of lexical functions. Our work presents a methodology for the implementation of collocations in a multilingual text realization engine, GÉCO, that relies on simple and complex syntagmatic standard lexical functions. The principal aspect of the methodology consists of regrouping lexical functions that show a similar behavior into generic patterns. As a result, 26 000 lexical functions have been implemented, which is a considerable progress in the treatment of collocations in multilingual text realization.

Keyphrases: Collocation, Natural language generation, Lexical functions, Meaning-Text Theory, Linguistics, Natural language processing
Étude de l’évolution dans la terminologie de l’informatique en anglais avant et après 2006

In this study, we propose a method to observe lexical changes (neology and necrology) in English in the field of computer science in short-period diachrony. Since computer science evolves quickly, we believe that a short-period diachronic approach (over a period of 10 years) lends itself to studying the terminology of that field. For this purpose, we built a corpus in English with articles taken from computer science magazines for the general public, PC Magazine and PC World, covering the years 2001 to 2010. The corpus was divided into two subcorpora: 2001-2005 and 2006-2010. We chose year 2006 as a pivot, because Facebook (the most popular social network) has been open to the public since that year, and we believed that would cause quick changes in computer science terminology. For each of the magazines, we selected one issue per year from 2001 to 2010, for a total of about 540,000 words for the 2001-2005 subcorpus and about 390,000 words for the 2006-2010 subcorpus. Each subcorpus was submitted to term extractor TermoStat to extract nominal, verbal and adjectival term candidates. We proceeded to three experiment groups, according to the reference corpus used. In the first experiment group (Exp1), we compared each subcorpus to the default reference corpus in TermoStat for English, a British National Corpus (BNC) extract. In the second experiment group (Exp2), we compared each subcorpus to the whole computer science corpus we created. In the third experiment group (Exp3), we compared the two subcorpora with each other. After cleaning up the term candidates lists thus obtained to retain only the terms in the field of computer science, and generating data about relative frequency and relative specificity of the terms between subcorpora, we proceeded to the validation of novelty and obsolescence of the first terms of each list to determine whether the proposed method works better with a particular type of lexical change (novelty or obsolescence), part of speech (nominal, verbal or adjectival term), or experiment group. The validation results show that the method seems to work better with neology extraction than with necrology extraction. Also, we had better results with nominal and adjectival terms than with verbal terms. Finally, we had much more results with Exp1 than with Exp2 and Exp3.

Keyphrases: Terminology, Short-period diachrony, Semi-automatic term extraction, Neology, Necrology, Computer science
Influencing the Properties of Latent Spaces

Machine learning models rely on learned parameters adapted to a given set of data to perform a task, such as classifying images or generating sentences. These learned parameters form latent spaces which can adapt various properties, to impact how well the model performs. Enabling a model to better fit properties of the data in its latent space can improve the performance of the model. One criteria for quality is the set of properties expressed by the latent space - that is, for example, topological properties of the learned representation. We develop a model which leverages a variational autoencoder’s generative ability and augments it with the ladder network’s lateral connections for discrimination. We propose a method to decouple two tasks perfomed by convolutional layers (that of learning useful filters for feature extraction, and that of arranging the learned filters such that the next layer may train eff ectively) by using interspersed fully-connected layers. Finally, we apply batch normalization to the recurrent state of the pixel-rnn layer and show that it significantly improves convergence speed as well as slightly improving overall performance. We show results applied in unsupervised and supervised settings, and augment models with various inter-layer interractions, such as encoder-to-decoder connections, affine post-layer transformations, and side-network connections. The effects of the proposed methods are assessed by measuring supervised performance or the quality of samples produced by the model and training curves. Models and methods are tested on popular image datasets such as MNIST and CIFAR10 and are compared to the state-of-the-art on the task they are applied to.

Keyphrases: Non-supervise, Machine learning, Deep learning, Computer vision, Unsupervised, Autoencoder, Neural network
Sur l’identification des états produits par une source quantique maximalement décorrélée

We define a maximally uncorrelated quantum source as an ensemble of quantum states, each taken in a different base from a set of mutually unbiased basis and such that the number of states equals the dimension of the space they live in. We explore upper bounds on the probability of distinguishing such states using numerical and analytical techniques. We also propose a novel cryptographic protocol for a non interactive proof of knowledge in which such a source is used as the main technical tool for the security proof.

Keyphrases: Identification, Quantum computing, Cryptography, Information theory, Semidefinite optimization, Distinguishability, Measure, Proof of knowledge
Learning a graph made of boolean function nodes : a new approach in machine learning

In this document we present a novel approach in machine learning for classification. The framework we propose is based on boolean circuits, more specifically the classifier produced by our algorithm has that form. Using bits and boolean gates enable the learning algorithm and the classifier to use very efficient boolean vector operations. The accuracy of the classifier we obtain with our framework compares very favourably with those produced by conventional techniques, both in terms of efficiency and accuracy. Furthermore, the framework can be used in a context where information privacy is a necessity, for example we can classify private data. This can be done because computation can be performed only through boolean circuits as encrypted data is quantized in bits. Moreover, assuming that the classifier was trained, it can then be easily implemented on FPGAs (i.e., Field-programmable gate array) as those circuits are also based on logic gates and bitwise operations. Therefore, our model can be easily integrated in real-time classification systems.

Keyphrases: Classification, FPGA, Machine learning, Classifier, Private data