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Romain, Sandra. "Identification, génotypage et représentation des variants de structure dans les pangénomes." Electronic Thesis or Diss., Université de Rennes (2023-....), 2024. https://ged.univ-rennes1.fr/nuxeo/site/esupversions/71b8c90f-bac9-4948-9bb1-a4b6d953f322.
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Les variants structuraux (SVs), des variations génomiques de plus de 50 pb, contribuent de manière significative à la diversité génétique et à l'évolution des espèces. La détection et le génotypage précis des SVs est crucial pour comprendre leur rôle dans la variation phénotypique et l'adaptation. Les graphes de variation (VGs) et graphes de pangénomes (PGs), qui représentent les variations génomiques comme des chemins alternatifs dans un graphe, offrent une approche prometteuse pour l'analyse des SVs. Cette thèse explore l'utilisation des VGs et PGs pour la détection et le génotypage des SVs, en se concentrant sur un complexe de quatre espèces de papillons Coenonympha alpins. Deux outils bio-informatiques ont été développés au cours de cette thèse : (1) SVJedi-graph, le premier génotypeur de SVs à partir de lectures longues utilisant un VG pour représenter les SVs, fournissant une précision de génotypage supérieure aux outils de l’état de l’art, en particulier pour les SVs proches et chevauchants, et (2) INVPG-annot, un outil d’identification des inversions dans les PGs, qui a permi de démontrer que les inversions sont représentées par différentes topologies dans les PGs selon l’outil de construction utilisé. L'analyse comparative des génomes des papillons Coenonympha a permis d'identifier douze grandes inversions (≥ 100 kbp) entre les quatre espèces, dont certaines pourraient jouer un rôle dans l'isolement reproductif et l'adaptation locale de deux de ces espèces. Bien que l'approche basée sur les PGs présente des avantages pour la comparaison de génomes, des défis restent à relever pour l'analyse des grands variants comme les inversionsStructural variants (SVs), genomic variations of more than 50 bp, contribute significantly to genetic diversity and species evolution. Accurate detection and genotyping SVs is crucial to understanding their role in phenotypic variation and adaptation. Variation graphs (VGs) and pangenome graphs (PGs), which represent genomic variations as alternative paths in a graph, offer a promising approach for the analysis of SVs. This thesis explores the use of VGs and PGs for the detection and genotyping of SVs, focusing on a complex of four species of alpine Coenonympha butterflies. Two bioinformatics tools were developed during this thesis: (1) SVJedi-graph, the first long-read SV genotyper using a VG to represent SVs, providing a genotyping accuracy superior to state-of-the-art tools, particularly for close and overlapping SVs, and (2) INVPG-annot, a tool for identifying inversions in PGs, which demonstrated that inversions are represented by different topologies in PGs depending on the construction tool used. Comparative analysis of the Coenonympha butterfly genomes identified twelve large inversions (≥ 100 kbp) between the four species, some of which could play a role in the reproductive isolation and local adaptation of two of these species. While the PG-based approach offers advantages for genome comparison, challenges remain for the analysis of large variants such as inversions
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Goudin, Yoann. "L'intercompréhension en langues sinogrammiques : théories, représentations, enjeux, et modalités d'une didactique de la variation." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCF035.
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Cette thèse traite des fondements et modalités d'une didactique de l'intercompréhension entre les langues qui, au cours de leur histoire, ont été en contact avec la langue et l'écriture chinoises, et dont les lexiques contemporains conservent une trace profonde. Cette étude explore dans quelle mesure il est possible de concevoir un enseignement-apprentissage qui tiendrait compte des acquis d'une première expérience d'apprentissage d'une de ces langues pour en apprendre une autre. La thèse défendue repose sur une refondation didactique du sinogramme au moyen d'une réévaluation non plus seulement graphique mais surtout phonologique afin d'entraîner les apprenants à émettre des hypothèses quant à la réalisation de ces sinogrammes dans la langue-cible. Il y a trois parties. Premièrement, il s'agit d'une discussion épistémologique sur la connaissance de l'écriture chinoise en Europe, la réduction de ce système à sa seule dimension graphique - voire idéographique - et l'incapacité des savants européens à intégrer la culture phonologique très développée qui constitue selon cette thèse la matrice sur laquelle fonder l'intercompréhension entre les langues d'Asie Orientale à l'instar de la grammaire contrastive pour les langues romanes. Ensuite, après une recontextualisation des différentes approches didactique des sinogrammes, sont traitées les modalités mises en œuvre pour préparer à l'intercompréhension : tout d'abord, une refondation de l'enseignement-apprentissage du système sinogrammique non plus au moyen de la programmation des types les plus fréquents dans les lexiques contemporains, mais à travers une approche globale incluant la compréhension des principes de toute l'économie du système graphique . Enfin, il est procédé à la présentation de la transposition sinogrammique, ultime contribution de cette thèse et opération qui permet à l'apprenant de passer de la lecture d'un sinogramme dans une langue-pont à celle dans une langue-cibleThis doctoral thesis analyzes the current teaching and learning models among languages that were, and still are, in contact with the Chinese script, and that retain this influence in their modern lexicon : the sinogramic languages. This thesis asserts that such a course can be designed through a complete didactic reformulation of how to teach sinograms, not only in their graphic dimension, but also their phonological identity, in order for the student to imagine pronouncing a sinogram in the target-language according to his/her understanding of an already acquired 'bridge-language'. The thesis is divided into three parts. First, there is an epistemological discussion of the European approach to Chinese language and script, with the sole graphic - «ideographic» - focus, which shadowed traditional phonological practices. Next, the design of an alternative approach is proposed in which sinogram-based learning is not rooted in the so called concentrated approach, according to which sinogram types are selected in order of their frequency and adaptability within the contemporary lexicon. This alternative approach is discussed based on the training of the sinogramic system as a whole: the global approach. Finally, the main process for mutual understanding, which is called sinogramic transposition, is introduced to show how students can be trained to understand and produce readings of sinograms in the target-language
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Jaillard, Dancette Magali. "Vers une cartographie fine des polymorphismes liés à la résistance aux antimicrobiens." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1282/document.
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Mieux comprendre les mécanismes de la résistance aux antibiotique est un enjeu important dans la lutte contre les maladies infectieuses, qui fait face à la propagation de bactéries multi-résistantes. Les études d'association à l'échelle des génomes sont des outils puissants pour explorer les polymorphismes liés aux variations phénotypiques dans une population. Leur cadre méthodologique est très documenté pour les eucaryotes, mais leur application aux bactéries est très récente. Durant cette thèse, j'ai cherché à rendre ces outils mieux adaptés aux génomes plastiques des bactéries, principalement en travaillant sur la représentation des variations génétiques. En effet, parce que les bactéries ont la capacité à échanger du matériel génétique avec leur environnement, leurs génomes peuvent être trop différents au sein d'une espèce pour être alignés contre une référence. La description des variations par des fragments de séquence de longueur k, les k-mers, offre la flexibilité nécessaire mais ne permet pas une interprétation directe des résultats obtenus. La méthode mise au point teste l'association de ces k-mers avec le phénotype, et s'appuie sur un graphe de De Bruijn pour permettre la visualisation du contexte génomique des k-mers identifiés par le test, sous forme de graphes. Cette vue synthétique renseigne sur la nature de la séquence identifiée: il peut par exemple s'agir de polymorphisme local dans un gène ou de l'acquisition d'un gène dans un plasmide. Le type de variant représenté dans un graphe peut être prédit avec une bonne performance à partir de descripteurs du graphe, rendant plus opérationnelles les approches par k-mers pour l'étude des génomes bactériensThe emergence and spread of multi-drug resistance has become a major worldwide public health concern, calling for better understanding of the underlying resistance mechanisms. Genome-wide association studies are powerful tools to finely map the genetic polymorphism linked to the phenotypic variability observed in a population. However well documented for eukaryotic genome analysis, these studies were only recently applied to prokaryota.Through this PhD project, I searched how to better adapt these tools to the highly plastic bacterial genomes, mainly by working on the representation of the genetic variations in these genomes. Indeed, because the bacteria have the faculty to acquire genetic material by a means other than direct inheritance from a parent cell, their genomes can differ too much within a species to be aligned against a reference. A representation using sequence fragments of length k - the so-called k-mers - offers the required flexibility but generates redundancy and does not allow for a direct interpretation of the identified associations. The method we set up tests the association of these k-mers with the phenotype, and takes advantage of a De Bruijn graph (DBG) built over all genomes to remove the local redundancy of k-mers, and offer a visualisation of the genomic context of the k-mers identified by the test. This synthetic view as DBG subgraphs informs on the nature of the identified sequence: e.g. local polymorphism in a gene or gene acquired through a plasmid. The type of variant can be predicted correctly in 96% of the cases from descriptors of the subgraphs, providing a tractable framework for k-mer-based association studies
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Hafiene, Yosra. "Continuum limits of evolution and variational problems on graphs." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC254/document.
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L’opérateur du p-Laplacien non local, l’équation d’évolution et la régularisation variationnelle associées régies par un noyau donné ont des applications dans divers domaines de la science et de l’ingénierie. En particulier, ils sont devenus des outils modernes pour le traitement massif des données (y compris les signaux, les images, la géométrie) et dans les tâches d’apprentissage automatique telles que la classification. En pratique, cependant, ces modèles sont implémentés sous forme discrète (en espace et en temps, ou en espace pour la régularisation variationnelle) comme approximation numérique d’un problème continu, où le noyau est remplacé par la matrice d’adjacence d’un graphe. Pourtant, peu de résultats sur la consistence de ces discrétisations sont disponibles. En particulier, il est largement ouvert de déterminer quand les solutions de l’équation d’évolution ou du problème variationnel des tâches basées sur des graphes convergent (dans un sens approprié) à mesure que le nombre de sommets augmente, vers un objet bien défini dans le domaine continu, et si oui, à quelle vitesse. Dans ce manuscrit, nous posons les bases pour aborder ces questions.En combinant des outils de la théorie des graphes, de l’analyse convexe, de la théorie des semi- groupes non linéaires et des équations d’évolution, nous interprétons rigoureusement la limite continue du problème d’évolution et du problème variationnel du p-Laplacien discrets sur graphes. Plus précisé- ment, nous considérons une suite de graphes (déterministes) convergeant vers un objet connu sous le nom de graphon. Si les problèmes d’évolution et variationnel associés au p-Laplacien continu non local sont discrétisés de manière appropriée sur cette suite de graphes, nous montrons que la suite des solutions des problèmes discrets converge vers la solution du problème continu régi par le graphon, lorsque le nombre de sommets tend vers l’infini. Ce faisant, nous fournissons des bornes d’erreur/consistance.Cela permet à son tour d’établir les taux de convergence pour différents modèles de graphes. En parti- culier, nous mettons en exergue le rôle de la géométrie/régularité des graphons. Pour les séquences de graphes aléatoires, en utilisant des inégalités de déviation (concentration), nous fournissons des taux de convergence nonasymptotiques en probabilité et présentons les différents régimes en fonction de p, de la régularité du graphon et des données initialesThe non-local p-Laplacian operator, the associated evolution equation and variational regularization, governed by a given kernel, have applications in various areas of science and engineering. In particular, they are modern tools for massive data processing (including signals, images, geometry), and machine learning tasks such as classification. In practice, however, these models are implemented in discrete form (in space and time, or in space for variational regularization) as a numerical approximation to a continuous problem, where the kernel is replaced by an adjacency matrix of a graph. Yet, few results on the consistency of these discretization are available. In particular it is largely open to determine when do the solutions of either the evolution equation or the variational problem of graph-based tasks converge (in an appropriate sense), as the number of vertices increases, to a well-defined object in the continuum setting, and if yes, at which rate. In this manuscript, we lay the foundations to address these questions.Combining tools from graph theory, convex analysis, nonlinear semigroup theory and evolution equa- tions, we give a rigorous interpretation to the continuous limit of the discrete nonlocal p-Laplacian evolution and variational problems on graphs. More specifically, we consider a sequence of (determin- istic) graphs converging to a so-called limit object known as the graphon. If the continuous p-Laplacian evolution and variational problems are properly discretized on this graph sequence, we prove that the solutions of the sequence of discrete problems converge to the solution of the continuous problem governed by the graphon, as the number of graph vertices grows to infinity. Along the way, we provide a consistency/error bounds. In turn, this allows to establish the convergence rates for different graph models. In particular, we highlight the role of the graphon geometry/regularity. For random graph se- quences, using sharp deviation inequalities, we deliver nonasymptotic convergence rates in probability and exhibit the different regimes depending on p, the regularity of the graphon and the initial data
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Caron-Aparicio, Jean-Xavier. "Problèmes isopérimétriques sur les graphes quantiques." Master's thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66416.
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Scheper, Reiny W. A. "Studies on the biology and genetic variation of phomopsis on grapevine /." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phs325.pdf.
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Minichiello, Mark Joseph. "Analysis of genetic variation data using ancestral recombination graphs." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613255.
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Borrelli, William. "L'équation de Dirac en physique du solide et en optique non-lineaire." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLED021/document.
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Ces dernières années, de nouveaux matériaux bidimensionnels aux propriétés surprenantes ont été découverts, le plus connu étant le graphène. Dans ces matériaux, les électrons du niveau de Fermi ont une masse apparente nulle, et peuvent être décrits par l’équation de Dirac sans masse. Un tel phénomène apparaît dans des situations très générales, pour les matériaux bidimensionnels ayant une structure périodique en « nid d’abeille ». De plus, la prise en compte d’interactions mène à des équations de Dirac non linéaires. Ces équations apparaissent également dans l’étude des paquets d’ondes lumineuses dans certaines fibres optiques. Le but de cette thèse est d’étudier l’existence et la stabilité de solutions stationnaires de ces équations avec termes non linéaires sous-critiques et critiques, et de montrer qu’ils sont la limite de solutions stationnaires de l’équation de Schrödinger non linéaire à potentiel périodique dans certains régimes de paramètres. Du point de vue mathématique, on devra résoudre les équations d’Euler-Lagrange de fonctionnelles d'énergie fortement indéfinies faisant intervenir l’opérateur de Dirac. Il s’agira en particulier d’étudier le cas des non-linéarités avec exposant critique, encore mal comprises pour ce type de fonctionnelle, et qui apparaissent naturellement en optique non linéaire. Les résultats de cette thèse pourraient avoir un impact important en physique, en particulier en physique du solide et optique non linéaireRecently, new two-dimensional materials possessing unique properties have been discovered, the most famous being the graphene. In this materials, electrons at the Fermi level behave as massless particles and can be described by the massless Dirac equation. This phenomenon is quite general, and it is a common features of "honeycomb" periodic structures. Moreover, taking into account interaction leads to non-linear Dirac equations, which also appear in the description of light propagation in particular waveguides. The aim of the thesis is to study existence and stability of stationary solutions for those equations with both sub-critical and critical nonlinearities, and to show that they are limit of stationary solutions to the Schroedinger equation with honeycomb potential, for a suitable choice of parameters. This amounts to solving the Euler-Lagrange equation for strongly indefinite energy functionals, involving the Dirac operator. We will deal with critical nonlinearities, which are still poorly understood, and appear naturally in non-linear optics. This results may have an impact on the understanding some solid state or nonlinear optics systems
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Kumar, Sooraj. "Face recognition with variation in pose angle using face graphs /." Online version of thesis, 2009. http://hdl.handle.net/1850/9482.
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Gray, John D. "The basis of variation in the size and composition of grape berries." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phg7794.pdf.
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"Department of Horticulture, Viticulture and Oenology, Faculty of Agriculture and Natural Resource Sciences, The University of Adelaide, Waite Campus, Glen Osmond S.A." Bibliography: leaves 136-149 This investigated focussed on selected aspects of berry development and ripening that were subject to variation. Shiraz and Chardonnay were chosen as experimental varieties because these cultivars presented a large range of variability in the field. The extent of the variation within each of the recorded berry parameters was assessed using the coefficient of variation (CV), a unitless measure of sample variability relative to the sample mean, ideally suited to comparative studies.
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Balacheff, Florent. "Inégalités isopérimétriques sur les graphes et applications en géométrie différentielle." Montpellier 2, 2005. https://tel.archives-ouvertes.fr/tel-00010580.
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Smith, Andrew Duncan. "Total variation denoising and multiresolution on graphs, with applications to house price data." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540873.
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Wainwright, Martin J. (Martin James) 1973. "Stochastic processes on graphs with cycles : geometric and variational approaches." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8371.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (leaves 259-271).
Stochastic processes defined on graphs arise in a tremendous variety of fields, including statistical physics, signal processing, computer vision, artificial intelligence, and information theory. The formalism of graphical models provides a useful language with which to formulate fundamental problems common to all of these fields, including estimation, model fitting, and sampling. For graphs without cycles, known as trees, all of these problems are relatively well-understood, and can be solved efficiently with algorithms whose complexity scales in a tractable manner with problem size. In contrast, these same problems present considerable challenges in general graphs with cycles. The focus of this thesis is the development and analysis of methods, both exact and approximate, for problems on graphs with cycles. Our contributions are in developing and analyzing techniques for estimation, as well as methods for computing upper and lower bounds on quantities of interest (e.g., marginal probabilities; partition functions). In order to do so, we make use of exponential representations of distributions, as well as insight from the associated information geometry and Legendre duality. Our results demonstrate the power of exponential representations for graphical models, as well as the utility of studying collections of modified problems defined on trees embedded within the original graph with cycles. The specific contributions of this thesis include the following. We develop a method for performing exact estimation of Gaussian processes on graphs with cycles by solving a sequence of modified problems on embedded spanning trees.
(cont.) We introduce the tree-based reparameterization framework for approximate estimation of discrete processes. This perspective leads to a number of theoretical results on belief propagation and related algorithms, including characterizations of their fixed points and the associated approximation error. Next we extend the notion of reparameterization to a much broader class of methods for approximate inference, including Kikuchi methods, and present results on their fixed points and accuracy. Finally, we develop and analyze a novel class of upper bounds on the log partition function based on convex combinations of distributions in the exponential domain. In the special case of combining tree-structured distributions, the associated dual function gives an interesting perspective on the Bethe free energy.
by Martn J. Wainwright.
Ph.D.
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Landrieu, Loïc. "Learning structured models on weighted graphs, with applications to spatial data analysis." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEE046/document.
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La modélisation de processus complexes peut impliquer un grand nombre de variables ayant entre elles une structure de corrélation compliquée. Par exemple, les phénomènes spatiaux possèdent souvent une forte régularité spatiale, se traduisant par une corrélation entre variables d’autant plus forte que les régions correspondantes sont proches. Le formalisme des graphes pondérés permet de capturer de manière compacte ces relations entre variables, autorisant la formalisation mathématique de nombreux problèmes d’analyse de données spatiales. La première partie du manuscrit se concentre sur la résolution efficace de problèmes de régularisation spatiale, mettant en jeu des pénalités telle que la variation totale ou la longueur totale des contours. Nous présentons une stratégie de préconditionnement pour l’algorithme generalized forward-backward, spécifiquement adaptée à la résolution de problèmes structurés par des graphes pondérés présentant une grande variabilité de configurations et de poids. Nous présentons ensuite un nouvel algorithme appelé cut pursuit, qui exploite les relations entre les algorithmes de flots et la variation totale au travers d’une stratégie de working set. Ces algorithmes présentent des performances supérieures à l’état de l’art pour des tâches d’agrégations de données geostatistiques. La seconde partie de ce document se concentre sur le développement d’un nouveau modèle qui étend les chaînes de Markov à temps continu au cas des graphes pondérés non orientés généraux. Ce modèle autorise la prise en compte plus fine des interactions entre noeuds voisins pour la prédiction structurée, comme illustré pour la classification supervisée de tissus urbainsModeling complex processes often involve a high number of variables with anintricate correlation structure. For example, many spatially-localized processes display spatial regularity, as variables corresponding to neighboring regions are more correlated than distant ones. The formalism of weighted graphs allows us to capture relationships between interacting variables in a compact manner, permitting the mathematical formulation of many spatial analysis tasks. The first part of this manuscript focuses on optimization problems with graph-structure dregularizers, such as the total variation or the total boundary size. We first present the convex formulation and its resolution with proximal splitting algorithms. We introduce a new preconditioning scheme for the existing generalized forward-backward proximal splitting algorithm, specifically designed for graphs with high variability in neighbourhood configurations and edge weights. We then introduce a new algorithm, cut pursuit, which used the links between graph cuts and total variation in a working set scheme. We also present a variation of this algorithm which solved the problem regularized by the non convex total boundary length penalty. We show that our proposed approaches reach or outperform state-of-the-art for geostatistical aggregation as well as image recovery problems. The second part focuses on the development of a new model, expanding continuous-time Markov chain models to general undirected weighted graphs. This allows us to take into account the interactions between neighbouring nodes in structured classification, as demonstrated for a supervised land-use classification task from cadastral data
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Le, Borgne Yvan. "Variations combinatoires sur des classes d'objets comptées par la suite de Catalan." Bordeaux 1, 2004. http://www.theses.fr/2004BOR12927.
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Cette thèse se situe dans le domaine de la combinaison énumérative. Il existe plusieurs techniques d'énumération des animaux dirigés selon l'aire : empilements bijections avec des chemins, équivalence avec la densité d'un modèle de gaz. On en propose des extensions dans le but de prendre aussi en compte des informations sur le périmètre de site. En utilisant un formalisme proche des grammaires algébriques et l'ordinateur, on propose un schéma commun à plusieurs bijections autour des mots de Dyck. La série génératrice des chemins de Dyck énumérés selon leur longueur et les interactions supérieures est un quotient de q-séries hypergéométriques basiques dans lesquelles apparaît un terme algébrique, une forme récente dans le cadre de la combinatoire énumérative. On donne trois preuves, de plus en plus combinatoires, de ce résultats. Pour tout graphe G, on donne unepreuve bijective du lien entre la distribution de l'activité externe des arbres couvrants, utilisé pour définir le polynôme de Tutte, et la distribution du nombre de grains des configurations récurrentes du modèle du tas de sable.
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Yuan, Zhan. "Multiphase implicit modeling and variational blue noise sampling." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/197095.
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This thesis investigates two fundamental problems in computer graphics including object modeling and sampling. In object modeling problems, implicit function is widely used. It has a wide range of applications in entertainment, engineering and medical imaging. A standard two-phase implicit function only represents the interior and exterior of a single object. To facilitate solid modeling of heterogeneous objects with multiple internal regions, object-space multiphase implicit functions are much desired. Multiphase implicit functions have much potential in modeling natural organisms, heterogeneous mechanical parts and anatomical atlases. In the first part of this thesis, we introduce a novel class of object-space multiphase implicit functions that are capable of accurately and compactly representing objects with multiple internal regions. Our proposed multiphase implicit functions facilitate true object-space geometric modeling of heterogeneous objects with non-manifold features. We present multiple methods to create object-space multiphase implicit functions from existing data, including meshes and segmented medical images. Our algorithms are inspired by machine learning algorithms for training multicategory max-margin classifiers. Comparisons demonstrate that our method achieves an error rate one order of magnitude smaller than alternative techniques.
In the second part of this thesis we study another important problem, sampling, which is a core process for numerous graphics applications including rendering, non-photorealistic image stippling, imaging, and geometry processing. Among all the existing sampling algorithms, blue noise point sampling is especially popular because it can generate spatial uniform point distribution with no aliasing artifacts. We present a new and versatile variational framework for generating point distributions with high-quality blue noise characteristics while precisely adapting to given density functions. Different from previous approaches based on discrete settings of capacity-constrained Voronoi tessellation, we cast the blue noise sampling generation as a variational problem with continuous settings. Based on an accurate evaluation of the gradient of an energy function, an efficient optimization is developed which delivers significantly faster performance than the previous optimization-based methods. Our framework can easily be extended to generating blue noise point samples on manifold surfaces and for multi-class sampling. The optimization formulation also allows us to naturally deal with dynamic domains, such as deformable surfaces, and to yield blue noise samplings with temporal coherence. We present experimental results to validate the efficacy of our variational framework.
A core step in our blue noise sampling algorithm is to compute the Voronoi diagram. This is a fundamental geometry structure which has numerous applications including computer animation, pattern recognition and so on. Efficient computation of Voronoi diagram is critical for improving the performance of these applications. Thus, we also study the problem of using the GPU to compute the generalized Voronoi diagram (GVD) for higher-order sites, such as line segments and curves. We propose an algorithm that can compute considerately more accurate GVD with much less memory than using the existing algorithms, with only moderate increase of the running time.published_or_final_version
Computer Science
Doctoral
Doctor of Philosophy
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Pandey, Arti. "Algorithmic aspects of domination and its variations." Thesis, IIT Delhi, 2016. http://localhost:8080/xmlui/handle/12345678/7038.
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Salavessa, Isabel. "Graphs with parallel mean curvature and a variational problem in conformal geometry." Thesis, University of Warwick, 1987. http://wrap.warwick.ac.uk/99902/.
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This thesis essentially deals with two basic problems, one in Rieinannian, the other in Conformal Geometry, described in Part I resp. Part III. Part II can be considered as an interlude serving as a sort of bridge between Riemannian and Comformal Geometry.
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Peterson, Nicholas Richard. "On Random k-Out Graphs with Preferential Attachment." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1370527839.
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Schoch, Christina Sigrid. "Teacher Variations When Administering Math Graphics Items to Students With Visual Impairments." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194668.
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This exploratory study investigated the techniques used by teachers of the visually impaired when administering math questions with graphics to students with blindness or low vision. The researcher observed and videotaped 10 pairs of students with visual impairments and their teachers while the students were taking a test that consisted of 12 graphic math items and found a wide variance existed between teachers in the administering of mathematical test items with graphics to their students. The most prevalent teacher behaviors observed were teacher initiation and graph detail description. For the majority of the teacher initiated responses, teachers gave information on a specific detail of the math graphic. Students predominantly asked for clarification regarding the math graphic itself or clarification of the math problem itself. Teachers used a variety of factors in determining if and when students required assistance during testing for large print or tactile graphics. No statistical significance was found between braille and large print groups with regard to teacher variation, student variation, and scores on test items, No relationship was found between correct answers on the test and teacher variation scores but a strong, positive correlation existed for total test time and teacher variation scores. In addition, there was no statistical significance, between the six math graph types used in this study. Hand movements of braille students were also observed, 90% of students using either both hands or mostly both hands when exploring the tactile graphic math problem. A horizontal movement was the primary direction students used when examining the tactile graphic. Recommendations were made regarding future research with large print and tactile graphics
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De, Santis Simone. "Quantum Median Filter for Total Variation denoising." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
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In this work we present Quantum Median Filter, an image processing algorithm for applying Total Variation denoising to quantum image representations.
After a brief introduction to TV model and quantum computing, we present QMF algorithm and discuss its design and efficiency; then we implement and simulate the quantum circuit using Qiskit library; finally we apply it to a set of noisy images, in order to compare and evaluate experimental results.
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Khachatryan, Anush [Verfasser]. "Extensions and variations of the two-person game on graphs / Anush Khachatryan. Fakultät für Mathematik." Bielefeld : Universitätsbibliothek Bielefeld, Hochschulschriften, 2012. http://d-nb.info/1024640698/34.
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Chbani, Zaki. "Convergence épigraphique des fonctions et convergence en graphe des opérateurs : Quelques applications en calcul des variations." Montpellier 2, 1993. http://www.theses.fr/1993MON20075.
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Des questions d'approximations des regularisations et de convergence, liees au domaine de l'analyse non lineaire, sont traitees. En premier lieu, on donne une caracterisation de la convergence de certaines fonctionnelles integrales en terme de convergence des coefficients de leurs integrandes. On se consacre ensuite a l'etude de l'approximee de lasry-lions d'une fonction definie sur un espace de hilbert, pour un choix critique des parametres. Par ailleurs, le resultat d'equivalence entre convergence au sens d'attouch-wets d'une suite de fonctions definies sur un espace super reflexif et convergence au meme sens des graphes de leur sous differentiels est precisee. On introduit enfin, une notion de recession pour un operateur maximal monotone defini sur un espace de hilbert. L'un des objectifs est la resolution d'equations gouvernees par des maximaux monotones non coercifs
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Ta, Vinh-Thong. "Equations aux différences partielles définies sur des graphes pour le traitement d'images et de données." Caen, 2009. http://www.theses.fr/2009CAEN2064.
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Cette thèse s’intéresse aux traitements d’images et de données non uniformes en utilisant le formalisme des équations aux différences partielles définies sur des graphes pondérés. Nous exploitons ce formalisme afin de transcrire et d’adapter des modèles définis dans le domaine continu vers des formulations discrètes. Les modèles continus considérés dans ce manuscrit proviennent du domaine du traitement des images et sont définis comme des modèles variationnels ou des approches basées sur des équations aux dérivées partielles. Nous nous sommes intéressés à des modèles de régularisation, à la morphologie mathématique et à l’équation eikonale. Afin de transcrire ces modèles définis dans le domaine continu vers des formulations discrètes, nous avons introduit une large famille de nouveaux opérateurs différentiels discrets définis sur des graphes pondérés : différences pondérées, gradients discrets, p-Laplacien. Ces opérateurs permettent de redéfinir les modèles continus considérés dans un cadre discret mais également de proposer un formalisme général permettant de considérer de nombreux problèmes liées aux traitements des images et, plus généralement, de données arbitraires. À partir des modèles discrets de régularisation, de morphologie mathématique et de l’équation eikonale, nous montrons dans ce manuscrit les potentialités de notre formalisme pour des applications telles que le filtrage, la simplification, la segmentation, le regroupement et la classification d’images et de données. Notre formalisme unifie également les traitements locaux et non locaux basés sur des patchs. Nous avons généralisé l’utilisation de ce type de configuration dans les problématiques considérées et montré la supériorité de ces schémas dans le contexte du traitement des images. Notre formalisme est basé sur des graphes pondérés. Cela nous permet d’étendre les modèles définis dans le domaine continu aux traitements de n’importe quel type de donnée pouvant être représenté par cette structure (par exemple des images, des collections d’images, des nuages de points, des variétés, des bases de données, etc. ). Finalement, ces travaux de thèse permettent d’envisager de nombreuses pistes de recherche tant dans le domaine du traitement des images que dans des domaines tels que celui de l’apprentissage ou de la fouille de donnéesThis works deals with images and non uniform data processing by partial difference equations (PdE) over weighted graphs. Transcription and adaption of continuous models to discrete formulations are considered within this PdEs-based framework. The considered continuous models (from image processing domain) are defined as variational models or approaches based on partial differential equations. The continuous models considered in this work are: regularization models, mathematical morphology, and the eikonal equation. To adapt these latter models within a discrete setting, we introduce a large family of discrete differential operators defined on weighted graphs: weighted differences, discrete gradients and p-Laplacian. These operators enable the transcription and the adaption of continuous models and provide a general formulation for considering numerous applications for images and arbitrary data. Potentialities of our discrete regularization, mathematical morphology and eikonal equation models are shown in applications such as image and data filtering, simplification, segmentation, clustering and classification. Our formulation also unifies local and non local patch-based processing. We have intensively used this latter configuration and shown the superiority of such a scheme in the context of image processing. Our approach is based on weighted graphs. This point provides a natural extension of continuous models for the processing of arbitrary data that can be represented by a weighted graph (for instance: images, manifolds, data sets, data bases, etc. ). Finally, this work opens new insights for image processing and new possible applications in machine learning
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Ni, Kang-Yu. "Variational PDE-based image segmentation and inpainting with applications in computer graphics." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1666392461&sid=2&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Kural, Deniz. "Methods for Inter- and Intra-Species Genomics for the Detection of Variation and Function." Thesis, Boston College, 2014. http://hdl.handle.net/2345/bc-ir:104053.
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Thesis advisor: Gabor T. MarthThis thesis concerns itself with the development of methods for comparing genomes. Chapter 2 is a comparative genomics investigation of coding regions across multiple species. Regions of the genome coding for proteins show higher conservation than non-coding regions. Furthermore, we show that a portion of coding regions are conserved beyond the requirements of protein conservation, supporting functions such as microRNA binding and splicing enhancement, providing the non-coding functional impetus to conservation. In Chapter 3, we focus on the detection and characterization of a particular type of structural variation - mobile element insertions (MEIs). While there are many types of mobile elements in the human genome, three of these are active and cause most of the MEI variation observed in humans: ALU, L1 and SVA elements. We detect variation across 1000 Genomes Pilot populations caused by these elements, assemble ALU elements to single nucleotide resolution, and determine actively copying species of this element. We've developed a variety of algorithmic approaches to MEI detection, and present these. Chapter 4 outlines an approach to remedy reference bias via the incorporation of variation data into the reference. In particular, we construct a pan-genome reference, demonstrated concretely via resolving ALU regions, and develop new alignment software to align against this enriched reference structure
Thesis (PhD) — Boston College, 2014
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Biology
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Pal, Asmita. "Split Latency Allocator: Process Variation-Aware Register Access Latency Boost in a Near-Threshold Graphics Processing Unit." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7155.
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Over the last decade, Graphics Processing Units (GPUs) have been used extensively in gaming consoles, mobile phones, workstations and data centers, as they have exhibited immense performance improvement over CPUs, in graphics intensive applications. Due to their highly parallel architecture, general purpose GPUs (GPGPUs) have gained the foreground in applications where large data blocks can be processed in parallel. However, the performance improvement is constrained by a large power consumption. Likewise, Near Threshold Computing (NTC) has emerged as an energy-efficient design paradigm. Hence, operating GPUs at NTC seems like a plausible solution to counteract the high energy consumption. This work investigates the challenges associated with NTC operation of GPUs and proposes a low-power GPU design, Split Latency Allocator, to sustain the performance of GPGPU applications.
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Sibel, Jean-Christophe. "Region-based approximation to solve inference in loopy factor graphs : decoding LDPC codes by the Generalized Belief Propagation." Phd thesis, Université de Cergy Pontoise, 2013. http://tel.archives-ouvertes.fr/tel-00905668.
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This thesis addresses the problem of inference in factor graphs, especially the LDPC codes, almost solved by message-passing algorithms. In particular, the Belief Propagation algorithm (BP) is investigated as a particular message-passing algorithm whose suboptimality is discussed in the case where the factor graph has a loop-like topology. From the equivalence between the BP and the Bethe approximation in statistical physics that is generalized to the region-based approximation, is detailed the Generalized Belief Propagation algorithm (GBP), a message-passing algorithm between clusters of the factor graph. It is experimentally shown to surpass the BP in the cases where the clustering deals with the harmful topological structures that prevents the BP from rightly decoding any LDPC code, namely the trapping sets. We do not only confront the BP and the GBP algorithms according to their performance from the point of view of the channel coding with the error-rate, but also according to their dynamical behaviors for non-trivial error-events for which both algorithms can exhibit chaotic beahviors. By means of classical and original dynamical quantifiers, it is shown that the GBP algorithm can overcome the BP algorithm.
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Lee, Sunmi. "The edge-isoperimetric problem for the square tessellation of plane." CSUSB ScholarWorks, 2000. https://scholarworks.lib.csusb.edu/etd-project/1622.
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The solution for the edge-isoperimetric problem (EIP) of the square tessellation of plane is investigated and solved. Summaries of the stabilization theory and previous research dealing with the EIP are stated. These techniques enable us to solve the EIP of the cubical tessellation.
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Carrier, Grégory. "Bases moléculaires de la variation clonale chez la vigne (Vitis vinifera L.) : approche pangénomique." Thesis, Montpellier, SupAgro, 2011. http://www.theses.fr/2011NSAM0039/document.
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L'exploitation de la variation clonale est une des voies d'amélioration utilisée chez un grand nombre de plantes d'intérêts agronomiques telles que la pomme de terre, le café et la vigne. En effet, après plusieurs cycles de reproduction végétative, des caractéristiques agronomiques stables apparaissent donnant naissance à une diversité phénotypique remarquable, appelée « diversité clonale ». Chez la vigne, cette diversité clonale est d'une importance majeure pour les viticulteurs puisqu'elle permet une amélioration variétale sans changer d'identité de cépage en conformité avec la réglementation fixée par Appellations d'Origine Protégée. L'hypothèse la plus parcimonieuse expliquant cette diversité phénotypique clonale est l'accumulation de mutations somatiques au cours des cycles de reproduction végétative. L'objectif de cette thèse a été de dresser un panorama le plus exhaustif possible des différents polymorphismes moléculaires entre les génomes de plusieurs clones. Dans un premier temps trois clones de Pinot ont été séquencés par la technique 454 GS-FLX puis dans un second temps 11 clones de quatre cépages ont été séquencés la technique Illumina HiSeq 2000. Afin d'analyser la grande quantité de données obtenues, nous avons construit un pipeline d'analyse (Bacchus pipeline) permettant d'identifier tous les types de polymorphismes moléculaires entre les différents génomes.Nos résultats permettent, pour la première fois un inventaire exhaustif des polymorphismes moléculaires dans un contexte multiplication végétatif. L'ensemble des mutations polymorphes entre deux clones a pu être identifié, SNPs, indels (2,5 SNPs et 11,5 indels par Mb en moyenne) ainsi que des variations d'ordre structural (larges insertions ou délétions) représentant la classe la plus fréquente (129 évènements par Mb entre deux clones en moyenne). Afin d'évaluer le polymorphisme d'insertion généré par ces éléments nous en avons étudié quatre par une approche S-SAP sur plusieurs niveaux de diversité (inter-espèces, inter-cépages, inter-clones et entre plusieurs tissus d'un même individu). L'analyse phylogénétique au niveau des espèces est conforme à celle réalisée avec d'autres types de marqueurs moléculaires (SSR, SNP). Cependant, une forte instabilité de ces insertions a été confirmée entre les clones et entre les tissus d'un même d'individu. L'identification des clones par une méthodologie moléculaire serait d'une grande importance pour la filère. Pour cet objectif, nos résultats indiquent que les mutations de types SNP et petits indels qui sont certes moins fréquentes que les variations structurales mais qui sont plus stables semblent plus pertinentes pour la mise en place d'une méthodologie d'identification des clonesClonal variation is considered as an effective contribution to breeding programs of vegetatively propagated species with major agronomical interest such as banana, potato, coffee and grape. Indeed, after several propagation cycles, stable and heritable phenotypic variations appear giving rise to a phenotypic variation termed “clonal diversity”. This clonal diversity is very important for wine-growers because it allows preserving cultivars identity in the strict respect of Appellation (A.O.P) wines specifications The most parsimonious hypothesis explaining clonal phenotypic diversity is the accumulation of somatic mutations. The objective of my thesis was to provide a broad description of molecular polymorphisms in the context of vegetative propagation. Three clones were first sequenced by 454 GS-FLX technology and eleven clones were then sequenced with Illumina Hiseq2000 technique. To analyse the high quantity of data obtained, we built a pipeline (Bacchus pipeline) allowing the identification of all existing molecular polymorphisms between different genomes.All polymorphism types were observed: indels and SNPs which have a low polymorphism frequency (2.5 SNPs and 11.5 indels per Mb between two clones in average) and structural variations (large insertions or deletions) which have a high polymorphism frequency (129 per Mb between two clones in average) but are unstable. To evaluate stability and polymorphism level of these transposable elements, we have studied 4 elements using S-SAP method at different diversity levels (inter-species, inter-cultivars, inter-clones and between organs/tissues of a single individual). Our interspecific phylogenetic analysis is similar to other phylogenies performed with SSR or SNPs markers. However, we confirm the high instability of these elements between clones and between tissues in single individuals.Clone identification through molecular methods would be of high significance for the wine industry. SNP or small indels mutations are less frequent but more stable than structural variation and could be used for accurate clone identification
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Bui, Hoa. "Extremality and stationarity of collections of sets : metric, slope and normal cone characterisations." Thesis, Federation University of Australia, 2019. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/178600.
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Variational analysis, a relatively new area of research in mathematics, has become one of the most powerful tools in nonsmooth optimisation and neighbouring areas. The extremal principle, a tool to substitute the conventional separation theorem in the general nonconvex environment, is a fundamental result in variational analysis. There have seen many attempts to generalise the conventional extremal principle in order to tackle certain optimisation models. Models involving collections of sets, initiated by the extremal principle, have proved their usefulness in analysis and optimisation, with non-intersection properties (or their absence) being at the core of many applications: recall the ubiquitous convex separation theorem, extremal principle, Dubovitskii Milyutin formalism and various transversality/regularity properties. We study elementary nonintersection properties of collections of sets, making the core of the conventional definitions of extremality and stationarity. In the setting of general Banach/Asplund spaces, we establish nonlinear primal (slope) and linear/nonlinear dual (generalised separation) characterisations of these non-intersection properties. We establish a series of consequences of our main results covering all known formulations of extremality/ stationarity and generalised separability properties. This research develops a universal theory, unifying all the current extensions of the extremal principle, providing new results and better understanding for the exquisite theory of variational analysis. This new study also results in direct solutions for many open questions and new future research directions in the fields of variational analysis and optimisation. Some new nonlinear characterisations of the conventional extremality/stationarity properties are obtained. For the first time, the intrinsic transversality property is characterised in primal space without involving normal cones. This characterisation brings a new perspective on intrinsic transversality. In the process, we thoroughly expose and classify all quantitative geometric and metric characterisations of transversality properties of collections of sets and regularity properties of set-valued mappings.Doctor of Philosophy
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Serpaggi, Xavier. "Variations sur le calcul des vecteurs d'éclairement indirect." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2001. http://tel.archives-ouvertes.fr/tel-00804892.
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L'exploration des diverses solutions liées au problème de l'éclairement global en synthèse d'images a vu l'émergence de deux disciplines fort différentes. La plus ancienne est l'application d'un principe utilisé par les physiciens dans les calculs d'échanges thermiques. Dans le cas de la synthèse d'images, ce ne sont en fait que les grandeurs échangées qui diffèrent et les ondes infrarouges sont remplacées par la lumière visible. Ce ne sont donc plus des échanges thermiques qui sont traités, mais uniquement des échanges lumineux entres différentes surfaces : la radiosité. Plus récemment, nous avons vu l'application de concepts mathématiques statistiques (les méthodes de Monte-Carlo) à un algorithme de lancer de rayons : l'équation de rendu et sa résolution par le suivi de chemins. Le travail présenté dans cette thèse fait partie de cette seconde famille. Les vecteurs d'éclairement indirect (VEI) obtenus à l'aide du lancer de rayons,s'appliquent dans le cadre de scènes d'intérieur et utilisent, pour leur calcul,une méthode de Monte-Carlo. Les recherches que nous avons menées ont pour but de développer cette jeune méthode que sont les VEI. Nous avons,pour cela,tenté d'explorer différentes voies, parfois en appliquant des principes connus,parfois en proposant des méthodes originales. Le résultat est une collections de propositions permettant de calculer les VEI plus rapidement et plus précisément. Ces propositions se séparent en deux groupes bien distincts dont le premier est l'étude du calcul d'un VEI. Le second propose des améliorations pour visualiser l'éclairement indirect calculé avec les VEI.
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Aydemir, Evsen Ozlem. "Investigation of strain related to displacement transfer and along-strike variation using 3-D seismic interpretation, physical modelling and computer-graphics visualization." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0004/MQ28173.pdf.
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Kong, Junhua. "Analysis of genomic DNA methylation variations and roles during grape berry ripening." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0095.
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La vigne est une plante cultivée dans le monde entier dont l’importance économique est principalement liée à la production de vin. La baie de raisin est également l’un des principaux modèles d’étude pour les fruits non-climatériques notamment pour l’étude des mécanismes contrôlant le mûrissement des baies. Le développement de la baie de raisin est caractérisé par deux phases de croissance séparées par une phase de latence se produisant au moment de la véraison. La baie de raisin est composée de trois tissus principaux: la peau, la pulpe et les graines. La peau et la pulpe présentent une structure et une composition en métabolites distinctes et contribuent de manière différente à la qualité du vin, la pulpe fournissant essentiellement le sucre, les acides aminés et organiques alors que la peau est riche en anthocyanes. A l'heure actuelle, les mécanismes moléculaires impliqués dans le contrôle de la maturation des baies de raisin sont encore mal compris. Si l'ABA, le sucre et différents facteurs de transcription jouent un rôle important dans le contrôle de cette phase de développement, les mécanismes épigénétiques, en particulier la méthylation de l’ADN, apparaissent aussi comme des régulateurs importants du développement et du mûrissement des fruits charnus. Dans ce contexte, Le projet de thèse présenté vise à analyser le rôle de la méthylation de l’ADN (1) dans la maturation des baies de raisin et (2) dans la synthèse des anthocyanes en utilisant comme système modèle des cellules de baie de raisin cultivées in vitro.La culture in vitro de baies de raisin en présence d’inhibiteurs de la méthylation de l'ADN, aboutit à une inhibition de la maturation, suggérant que la méthylation de l’ADN joue un rôle crucial pour cette étape du développement chez la vigne. La pellicule et la chair de baies de raisin récoltées à divers stades de développement ont ensuite été analysées séparément pour déterminer les variations des transcriptomes, de l’abondance de différents métabolites, et de la méthylation de l'ADN. Les principaux résultats indiquent des variations des métabolites et du transcriptome, avec des spécificités liés au tissu analysé. En outre, l'analyse des variations de méthylation de l'ADN à deux stades de développement dans chacun de ces deux tissus révèle l’existence de variations de méthylation spécifiques à chaque tissu, tandis que les variations communes aux deux tissus restent limitées. Ces résultats suggèrent un contrôle de la méthylation de l’ADN spécifique à chaque tissu lors de la maturation de la baie. Cependant les régions différentiellement méthylées identifiées dans chaque tissu, ne sont pas associées à des gènes exprimés différentiellement au cours de la maturation des baies, ce qui pose la question du rôle de la méthylation de l’ADN dans le contrôle de l’expression génique dans les baies.Pour analyser le rôle de la méthylation de l’ADN dans le contrôle de la synthèse des anthocyanes, nous avons utilisé des suspensions de cellules de raisin du génotype Gamay Teinturier (GT), connues pour accumuler des anthocyanes lorsqu’elles sont cultivées à la lumière. L’utilisation de la zébularine, un inhibiteur de la méthylation d’ADN, permet de stimuler l’accumulation d'anthocyanes dans les cellules GT en présence de lumière, et de l’induire à l’obscurité. Les traitements à la zébularine provoquent en outre une limitation de la croissance cellulaire, une modification de l’accumulation des sucres solubles et acides organiques ainsi qu’une reprogrammation importante du transcriptome. Ces résultats suggèrent un effet général de la zébularine sur les cellules GT plutôt qu’un effet spécifique sur l’accumulation d’anthocyanes.Dans l'ensemble, les résultats indiquent que la méthylation de l'ADN est importante pour le contrôle de la maturation des fruits de la vigne, bien que les mécanismes qui sous-tendent les variations de la méthylation et leurs rôles dans les différents tissus de la baie de raisin restent à préciserGrapevine is a worldwide cultivated fruit crop with high economic importance mainly because of its usage for vine production. Grape berry is also one of the main models for non-climacteric fruits to study the mechanisms controlling the ripening process. Grape berry development is characterized by two phases of rapid size increase separated by a lag phase at the time of ripening induction. Grape berries are composed of three main tissues, the peel, the pulp and the seeds. Peel and pulp present distinct structure and metabolite composition and contribute in a different way to wine quality, the pulp providing sugar, amino and organic acids whereas the peel is important for anthocyanins and other phenolic compound abundance. At the present time, the molecular mechanisms involved in the control of grape berry ripening are still poorly understood. Recent results indicate that both ABA and sugar may be important signals together with various transcription factors. In addition, epigenetic mechanisms are now emerging as important regulators of fleshy fruit development, DNA methylation being critically important for tomato, sweet range and strawberry ripening.The present project aims at analyzing the potential role of DNA methylation in the control grape berry ripening. It also investigates the potential role of DNA methylation in the synthesis of anthocyanins, a compound of primary importance in peel of red grape berries, using in vitro grown fruit cells. To address these questions, grape berries cultivated in vitro were treated with DNA methylation inhibitors. Treatments resulted in delayed and reduced grape berry ripening, therefore sustaining the idea that DNA methylation plays critical roles at this developmental step. Grape berries harvested at various developmental stages were then dissected and each tissue was separately analyzed for transcriptomic, metabolic and DNA methylation variations. Main results indicate significant and distinct metabolic and transcriptomic variations consistent with each tissue following specific modifications during ripening. In addition, analysis of DNA methylation variations at two developmental stages in each tissue indicates both common and tissue specific changes in DNA methylation patterns during fruit ripening. A very small proportion of DMRs is found similarly in the pup and the peel, but most are tissue specific, also consistent with tissue specific control at this developmental phase. Of note, among the different DMRs identified in each tissue, only a few were associated with differentially expressed genes (DEG) during ripening, whereas most were not, questioning the general role of DNA methylation in the control of gene expression at this developmental transition in grape.As Anthocyanins are the most abundant polyphenolic compounds in the skin of red grape berries, we used grape cell suspensions of the Gamay Teinturier genotype, that are known to accumulate anthocyanins when grown in light conditions, to analyze the potential role of DNA methylation in their synthesis. GT cells cultivated in light conditions were treated with the DNA methyltransferase inhibitor zebularine, they accumulate higher quantities of anthocyanins. Of note, GT cells grown in the absence of light do not accumulate anthocyanins. However, zebularine was sufficient to induce anthocyanin accumulation in the absence of light. Zebularine treatments had significant additional effects on grape cells including, cell growth limitation, and modification of soluble sugar, organic acid or stilbene accumulation, together with important transcriptomic reprogramming, consistent with a general effect on cells rather than a specific effect on anthocyanin accumulation.Taken together, results are consistent with DNA methylation being important in the control of grape fruit ripening, although the precise mechanisms underlying methylation variations and roles in grape berries remain to be deciphered
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Le, Corre Gaëlle. "Variations non standard dans les écrits épistolaires de soldats de l'armée confédérée de l'état de Virginie." Thesis, Brest, 2015. http://www.theses.fr/2015BRES0063.
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Durant la guerre de Sécession (1861-1865), des milliers de soldats, de chaque côté du front, prirent leur plume afin de s'enquérir de leur famille et de donner des nouvelles du front. Généralement peu lettrés, la plupart de ces soldats ne maîtrisaient que très partiellement les codes de l'écrit. Le corpus sur lequel se base la présente recherche doctorale se compose de 366 lettres (soit environ 170 000 mots) rédigées par 80 soldats de première et deuxième classes originaires de Virginie. L'orthographe idiosyncratique et approximative de leurs écrits ainsi que les nombreuses variations morphosyntaxiques non standard permettent de mieux saisir ce que pouvait être le vernaculaire des locuteurs blancs issus des couches les plus basses de la société virginienne durant la première moitié du XIXe siècle.Selon Guy Bailey (1997), certaines caractéristiques du vernaculaire du Sud des Etats-Unis (Southern American English) seraient apparues après la guerre de Sécession et seraient le fruit d'une réaction identitaire face à la domination du Nord et à l'humiliation causée par la défaite. Les variations non standard répertoriées dans le Virginia Civil War Corpus nous invitent à nuancer cette assertion. Malgré une orthographe phonétique et l'emploi de nombreuses variations morphosyntaxiques et lexicales non standard, leurs écrits révèlent la tension constante entre le registre paritaire et disparitaire. Cette perpétuelle oscillation est-elle le fruit d'un conflit interne entre différents modèles linguistiques ou est-elle, au contraire, le signe d'opérations énonciatives spécifiques ?Throughout the Civil War (1861-1865), thousands of low ranking soldiers on both sides of the conflict took up their pens to inquire after their families and give news from the front. Usually semiliterate, most of these soldiers were far from mastering written conventions. The 170,000-word corpus, on which this thesis is based, is composed of 366 letters written by 80 privates, corporals and sergeants from Virginia. Their idiosyncratic and ingenuous spellings as well as their use of non-standard morphosyntactic variations offer a great opportunity to gain further insight into the vernacular spoken by white lower-class people in Virginia around the middle of the 19th century.According to Guy Bailey (1997), certain specificities of the Southern American Vernacular English (SAVE) appeared after the Civil War, as a reaction against Northern domination and the humiliation caused by the defeat. The non standard variations found in the Virginia Civil War Corpus tend to question this hypothesis and reveal that most of the features, that are today associated with SAVE, were already present in low ranking soldiers' writings.Despite the phonetic spelling and the use of non-standard grammatical and lexical forms, the letters reveal that the soldiers were fully aware that their vernacular speech was not in line with academic conventions. We thus observe a constant tension between the academic prescriptive norm and non-standard variations. We may wonder if this constant oscillation is only triggered by an internal conflict between different linguistic models or if, on the contrary, the presence of these dialectal variations must be understood as signs of specific enunciative operations
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Couprie, Camille. "Graph-based variational optimization and applications in computer vision." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00666878.
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Many computer vision applications such as image filtering, segmentation and stereovision can be formulated as optimization problems. Recently discrete, convex, globally optimal methods have received a lot of attention. Many graph-based methods suffer from metrication artefacts, segmented contours are blocky in areas where contour information is lacking. In the first part of this work, we develop a discrete yet isotropic energy minimization formulation for the continuous maximum flow problem that prevents metrication errors. This new convex formulation leads us to a provably globally optimal solution. The employed interior point method can optimize the problem faster than the existing continuous methods. The energy formulation is then adapted and extended to multi-label problems, and shows improvements over existing methods. Fast parallel proximal optimization tools have been tested and adapted for the optimization of this problem. In the second part of this work, we introduce a framework that generalizes several state-of-the-art graph-based segmentation algorithms, namely graph cuts, random walker, shortest paths, and watershed. This generalization allowed us to exhibit a new case, for which we developed a globally optimal optimization method, named "Power watershed''. Our proposed power watershed algorithm computes a unique global solution to multi labeling problems, and is very fast. We further generalize and extend the framework to applications beyond image segmentation, for example image filtering optimizing an L0 norm energy, stereovision and fast and smooth surface reconstruction from a noisy cloud of 3D points
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Belhadj, Djedjiga. "Multi-GAT semi-supervisé pour l’extraction d’informations et son adaptation au chiffrement homomorphe." Electronic Thesis or Diss., Université de Lorraine, 2024. http://www.theses.fr/2024LORR0023.
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Cette thèse est réalisée dans le cadre du projet BPI DeepTech, en collaboration avec la société Fair&Smart, veillant principalement à la protection des données personnelles conformément au Règlement Général sur la Protection des Données (RGPD). Dans ce contexte, nous avons proposé un modèle neuronal profond pour l'extraction d'informations dans les documents administratifs semi-structurés (DSSs). En raison du manque de données d'entraînement publiques, nous avons proposé un générateur artificiel de DSSs qui peut générer plusieurs classes de documents avec une large variation de contenu et de mise en page. Les documents sont générés à l'aide de variables aléatoires permettant de gérer le contenu et la mise en page en respectant des contraintes visant à garantir leur proximité avec des documents réels. Des métriques ont été introduites pour évaluer la diversité des DSSs générés en termes de contenu et de mise en page. Les résultats de l'évaluation ont montré que les jeux de données générés pour trois types de DSSs (fiches de paie, tickets de caisse et factures) présentent un degré élevé de diversité, ce qui permet d'éviter le sur-apprentissage lors de l'entraînement des systèmes d'extraction d'informations. En s'appuyant sur le format spécifique des DSSs, constitué de paires de mots (mots-clés, informations) situés dans des voisinages proches spatialement, le document est modélisé sous forme de graphe où les nœuds représentent les mots et les arcs, les relations de voisinage. Le graphe est incorporé dans un réseau d'attention à graphe (GAT) multi-couches (Multi-GAT). Celui-ci applique le mécanisme d'attention multi-têtes permettant d'apprendre l'importance des voisins de chaque mot pour mieux le classer. Une première version de ce modèle a été utilisée en mode supervisé et a obtenu un score F1 de 96 % sur deux jeux de données de factures et de fiches de paie générées, et de 89 % sur un ensemble de tickets de caisse réels (SROIE). Nous avons ensuite enrichi le Multi-GAT avec un plongement multimodal de l'information au niveau des mots (avec des composantes textuelle, visuelle et positionnelle), et l'avons associé à un auto-encodeur variationnel à graphe (VGAE). Ce modèle fonctionne en mode semi-supervisé, capable d'apprendre à partir des données annotées et non annotées simultanément. Pour optimiser au mieux la classification des nœuds du graphe, nous avons proposé un semi-VGAE dont l'encodeur partage ses premières couches avec le classifieur Multi-GAT. Cette optimisation est encore renforcée par la proposition d'une fonction de perte VGAE gérée par la perte de classification. En utilisant une petite base de données non annotées, nous avons pu améliorer de plus de 3 % le score F1 obtenu sur un ensemble de factures générées. Destiné à fonctionner dans un environnement protégé, nous avons adapté l'architecture du modèle pour son chiffrement homomorphe. Nous avons étudié une méthode de réduction de la dimensionnalité du modèle Multi-GAT. Ensuite, nous avons proposé une approche d'approximation polynomiale des fonctions non-linéaires dans le modèle. Pour réduire la dimension du modèle, nous avons proposé une méthode de fusion de caractéristiques multimodales qui nécessite peu de paramètres supplémentaires et qui réduit les dimensions du modèle tout en améliorant ses performances. Pour l'adaptation au chiffrement, nous avons étudié des approximations polynomiales de degrés faibles aux fonctions non-linéaires avec une utilisation des techniques de distillation de connaissance et de fine tuning pour mieux adapter le modèle aux nouvelles approximations. Nous avons pu minimiser la perte lors de l'approximation d'environ 3 % pour deux jeux de données de factures ainsi qu'un jeu de données de fiches de paie et de 5 % pour SROIEThis thesis is being carried out as part of the BPI DeepTech project, in collaboration with the company Fair&Smart, primarily looking after the protection of personal data in accordance with the General Data Protection Regulation (RGPD). In this context, we have proposed a deep neural model for extracting information in semi-structured administrative documents (SSDs). Due to the lack of public training datasets, we have proposed an artificial generator of SSDs that can generate several classes of documents with a wide variation in content and layout. Documents are generated using random variables to manage content and layout, while respecting constraints aimed at ensuring their similarity to real documents. Metrics were introduced to evaluate the content and layout diversity of the generated SSDs. The results of the evaluation have shown that the generated datasets for three SSD types (payslips, receipts and invoices) present a high diversity level, thus avoiding overfitting when training the information extraction systems. Based on the specific format of SSDs, consisting specifically of word pairs (keywords-information) located in spatially close neighborhoods, the document is modeled as a graph where nodes represent words and edges, neighborhood connections. The graph is fed into a multi-layer graph attention network (Multi-GAT). The latter applies the multi-head attention mechanism to learn the importance of each word's neighbors in order to better classify it. A first version of this model was used in supervised mode and obtained an F1 score of 96% on two generated invoice and payslip datasets, and 89% on a real receipt dataset (SROIE). We then enriched the multi-GAT with multimodal embedding of word-level information (textual, visual and positional), and combined it with a variational graph auto-encoder (VGAE). This model operates in semi-supervised mode, being able to learn on both labeled and unlabeled data simultaneously. To further optimize the graph node classification, we have proposed a semi-VGAE whose encoder shares its first layers with the multi-GAT classifier. This is also reinforced by the proposal of a VGAE loss function managed by the classification loss. Using a small unlabeled dataset, we were able to improve the F1 score obtained on a generated invoice dataset by over 3%. Intended to operate in a protected environment, we have adapted the architecture of the model to suit its homomorphic encryption. We studied a method of dimensionality reduction of the Multi-GAT model. We then proposed a polynomial approximation approach for the non-linear functions in the model. To reduce the dimensionality of the model, we proposed a multimodal feature fusion method that requires few additional parameters and reduces the dimensions of the model while improving its performance. For the encryption adaptation, we studied low-degree polynomial approximations of nonlinear functions, using knowledge distillation and fine-tuning techniques to better adapt the model to the new approximations. We were able to minimize the approximation loss by around 3% on two invoice datasets as well as one payslip dataset and by 5% on SROIE
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Meister, Julio César. "Tracker Physics : objetos em movimento e registros de representação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/150248.
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Esta pesquisa traz um estudo sobre a construção inicial dos conceitos de limites e taxa de variação, com alunos do segundo ano do Ensino Médio da Escola Antônio de Castro Alves. Como metodologia utilizamos a perspectiva do Estudo de Caso (PONTE, 2006). O trabalho propõe a utilização do software Tracker Physics, que possibilita a análise de objetos em movimento gravados por vídeo a partir de diferentes registros gerados pelo software, tais como gráficos, tabelas e registros algébricos. Com o uso deste software e da teoria de Duval, procuramos responder à seguinte pergunta norteadora: como os alunos do Ensino Médio compreendem os conceitos de taxa de variação e de limite a partir de objetos em movimento analisados com o Tracker Physics? Por tratar-se de objetos em movimento, utilizamos a Física como meio para trabalharmos os conceitos matemáticos. Antes de chegarmos ao debate sobre limite e taxa de variação, a proposta levanta questões acerca da interpretação de gráficos, tabelas, equações e cálculos numéricos, que não são o escopo principal do trabalho, mas que são importantes para o processo de construção dos conceitos propostos, e a análise dos dados aponta resultados interessantes. Os dados da pesquisa são analisados à luz da teoria dos Registros Semióticos de Duval. Podemos apontar, ao final da pesquisa, que os alunos avançaram na compreensão dos conceitos abordados nas situações apresentadas e analisadas.This research brings a study about the initial construction of the concepts of limits and rate of variation, with students of the second year of High School of the School Antônio de Castro Alves. As methodology we use the case study perspective (PONTE, 2006). The work proposes the use of Tracker Physics software, which enables the analysis of moving objects recorded by video from different records generated by the software, such as graphs, tables and algebraic records. With the use of this software and Duval's theory, we try to answer the following guiding question: how do the students of the High School understand the concepts of rate of variation and limit from moving objects analyzed with Tracker Physics? Because we are dealing with moving objects, we use Physics as the means to work on mathematical concepts. Before we reach the debate about limit and rate of variation, the proposal raises questions about the interpretation of graphs, tables, equations and numerical calculations, which are not the main scope of the work, but which are important for the process of construction of the proposed concepts , And the analysis of the data points interesting results. The data of the research is analyzed in light of the theory of the Duval Semiotic Registers. We can point out, at the end of the research, that the students advanced in understanding the concepts addressed in the situations presented and analyzed.
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Holmes, Glen A. "Two computer-graphics variations (animated vs still) and their impact on the knowledge and performance of cognitive-behavioral skills: fire-safety training." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/37750.
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Fifty-six fourth-grade children served as participants in this study. Three training procedures (behavioral, animated-graphics, and still-graphics) were assessed for relative effectiveness in the acquisition of fire emergency skills and attainment of knowledge, Each of the training groups was compared to a no-treatment control group. Performance on dependent measures was assessed prior to and immediately following training. Hypotheses predicted that the behavioral and animated graphics conditions would produce the greatest level of skill and knowledge acquisition. Results demonstrated a significantly higher level of fire emergency skill acquisition and knowledge attainment for both the behavioral and animated graphics groups relative to the still graphics and no-training groups. The value of using animated versus static images in computerized instruction for fire-safety skills training was demonstrated.Ed. D.
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Ta, Vinh Thong. "Equations aux différences partielles définies sur des graphes pour le traitement d'images et de données." Phd thesis, Université de Caen, 2009. http://tel.archives-ouvertes.fr/tel-00472041.
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Cette thèse s'intéresse aux traitements d'images et de données non uniformes en utilisant le formalisme des équations aux différences partielles définies sur des graphes pondérés. Nous exploitons ce formalisme afin de transcrire et d'adapter des modèles définis dans le domaine continu vers des formulations discrètes. Les modèles continus considérés dans ce manuscrit proviennent du domaine du traitement des images et sont définis comme des modèles variationnels ou des approches basées sur des équations aux dérivées partielles. Nous nous sommes intéressés à des modèles de régularisation, à la morphologie mathématique et à l'équation eikonale. Afin de transcrire ces modèles définis dans le domaine continu vers des formulations discrètes, nous avons introduit une large famille de nouveaux opérateurs différentiels discrets définis sur des graphes pondérés: différences pondérées, gradients discrets, p-Laplacien. Ces opérateurs permettent de redéfinir les modèles continus considérés dans un cadre discret mais également de proposer un formalisme général permettant de considérer de nombreux problèmes liées aux traitements des images et, plus généralement, de données arbitraires. A partir des modèles discrets de régularisation, de morphologie mathématique et de l'équation eikonale, nous montrons dans ce manuscrit les potentialités de notre formalisme pour des applications telles que le filtrage, la simplification, la segmentation, le regroupement et la classification d'images et de données. Notre formalisme unifie également les traitements locaux et non locaux basés sur des patchs. Nous avons généralisé l'utilisation de ce type de configuration dans les problématiques considérées et montré la supériorité de ces schémas dans le contexte du traitement des images. Notre formalisme est basé sur des graphes pondérés. Cela nous permet d'étendre les modèles définis dans le domaine continu aux traitements de n'importe quel type de donnée pouvant être représenté par cette structure (par exemple des images, des collections d'images, des nuages de points, des variétés, des bases de données, etc.). Finalement, ces travaux de thèse permettent d'envisager de nombreuses pistes de recherche tant dans le domaine du traitement des images que dans des domaines tels que celui de l'apprentissage ou de la fouille de données.
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Pan, Chenyun. "A hierarchical optimization engine for nanoelectronic systems using emerging device and interconnect technologies." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53931.
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A fast and efficient hierarchical optimization engine was developed to benchmark and optimize various emerging device and interconnect technologies and system-level innovations at the early design stage. As the semiconductor industry approaches sub-20nm technology nodes, both devices and interconnects are facing severe physical challenges. Many novel device and interconnect concepts and system integration techniques are proposed in the past decade to reinforce or even replace the conventional Si CMOS technology and Cu interconnects. To efficiently benchmark and optimize these emerging technologies, a validated system-level design methodology is developed based on the compact models from all hierarchies, starting from the bottom material-level, to the device- and interconnect-level, and to the top system-level models. Multiple design parameters across all hierarchies are co-optimized simultaneously to maximize the overall chip throughput instead of just the intrinsic delay or energy dissipation of the device or interconnect itself. This optimization is performed under various constraints such as the power dissipation, maximum temperature, die size area, power delivery noise, and yield. For the device benchmarking, novel graphen PN junction devices and InAs nanowire FETs are investigated for both high-performance and low-power applications. For the interconnect benchmarking, a novel local interconnect structure and hybrid Al-Cu interconnect architecture are proposed, and emerging multi-layer graphene interconnects are also investigated, and compared with the conventional Cu interconnects. For the system-level analyses, the benefits of the systems implemented with 3D integration and heterogeneous integration are analyzed. In addition, the impact of the power delivery noise and process variation for both devices and interconnects are quantified on the overall chip throughput.
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Sanyal, Sourav. "Predicting Critical Warps in Near-Threshold GPGPU Applications Using a Dynamic Choke Point Analysis." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7545.
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General purpose graphics processing units (GP-GPU), owing to their enormous thread-level parallelism, can significantly improve the power consumption at the near-threshold (NTC) operating region, while offering close to a super-threshold performance. However, process variation (PV) can drastically reduce the GPU performance at NTC. In this work, choke points—a unique device-level characteristic of PV at NTC—that can exacerbate the warp criticality problem in GPUs have been explored. It is shown that the modern warp schedulers cannot tackle the choke point induced critical warps in an NTC GPU. Additionally, Choke Point Aware Warp Speculator, a circuit-architectural solution is proposed to dynamically predict the critical warps in GPUs, and accelerate them in their respective execution units. The best scheme achieves an average improvement of ∼39% in performance, and ∼31% in energy-efficiency, over one state-of-the-art warp scheduler, across 15 GPGPU applications, while incurring marginal hardware overheads.
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Marak, Laszlo. "On continuous maximum flow image segmentation algorithm." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00786914.
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In recent years, with the advance of computing equipment and image acquisition techniques, the sizes, dimensions and content of acquired images have increased considerably. Unfortunately as time passes there is a steadily increasing gap between the classical and parallel programming paradigms and their actual performance on modern computer hardware. In this thesis we consider in depth one particular algorithm, the continuous maximum flow computation. We review in detail why this algorithm is useful and interesting, and we propose efficient and portable implementations on various architectures. We also examine how it performs in the terms of segmentation quality on some recent problems of materials science and nano-scale biology
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Gementi-Spolzino, Mariana Moretto [UNESP]. "Consoantes fricativas: um estudo das relações entre letras e sons na lírica medieval galego-portuguesa." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154222.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo da presente tese é estudar as fricativas (sibilantes e chiantes) nas cantigas trovadorescas, a partir das relações existentes entre letras e sons e as possíveis grafias nas cantigas religiosas e profanas. O corpus é composto por 50 Cantigas de Santa Maria (CSM), das 420 cantigas marianas em louvor à Virgem Maria, compiladas em galego-português por Afonso X, e por 150 cantigas profanas, sendo 50 cantigas de amigo, 50 cantigas de amor e 50 cantigas de escárnio e maldizer. A metodologia utilizada baseia-se na análise das rimas e das variações gráficas presentes nas cantigas trovadorescas, o que nos possibilitou um estudo inédito sobre a realização fônica das fricativas (sibilantes e chiantes) de uma época da língua em que não há mais falantes vivos. Além disso, fez parte dos procedimentos metodológicos de nossa pesquisa a consulta a glossários, rimários e dicionários do português medieval, material que nos auxiliou no mapeamento das rimas nas cantigas medievais. A análise do sistema consonantal do Português Arcaico (PA), para estabelecer se havia ou não oposição entre os sons representados pelos grafemas focalizados, foi embasada no modelo estruturalista de Pike (1971 [1947]) e em obras que retomam o modelo de Pike, como Cagliari (2002), Souza e Santos (2012), Ferreira Netto (2011), Pickering (2010). Através da análise dos dados, verificamos que as consoantes fricativas na posição de onset silábico nas cantigas religiosas e profanas se comportam de maneira um pouco diferente nos dois corpora. Os segmentos representados pelos grafemas
The objective of this thesis is to study (sibilant and nonsibilant) fricatives on medieval cantigas as from the existing relation among graphemes and represented sounds and possible spelling in religious and secular songs. The corpus is composed by 50 Cantigas de Santa Maria (CSM in Portuguese acronyms), extracted from 420 Marian songs to worship the Virgin Mary, compiled in Galician-Portuguese by Afonso X, and 150 secular songs, composed by 50 cantigas de amigo (= friend songs), 50 cantigas de amor (= love songs) and 50 cantigas de escárnio e maldizer (= satirical songs). The methodology is based on the analysis of rhymes and spelling variations presented on medieval songs, in order to study the phonetic realization of fricatives from a language time with no more living speakers. In addition, our research consultation on glossaries, rhyming dictionaries and dictionaries of medieval Portuguese was part of the methodological procedure. The analysis of the consonantal system of archaic Portuguese (PA in Portuguese acronyms) to establish whether there was or not opposition among sounds represented by the focused graphemes was based on the structuralist model of Pike (1971 [1947]) and on contributions which resume Pike’s model, as Cagliari (2002), Sousa and Santos (2012), Ferreira Netto (2011), Pickering (2010). Through data analysis, we verified that fricative consonants on onset syllabic position present a little different behavior in religious and secular cantigas. Sounds represented by graphemes
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Barnuud, Nyamdorj Namjildorj. "Determining climate change impacts on viticulture in Western Australia." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/1677.
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Global climate model simulations indicate 1.3°C to 1.8°C increase in the Earth’s average temperature by middle of this century above the 1980 to 1999 average. The magnitude and rate of change of this projected warming is greater than the average warming during the last century. Global climate models project an even higher degree of warming later in the century also due to increasing grrenhouse gases concentrations in the atmosphere from human activity. Impacts of future climate change on viticulture are likely to be significant as viticulture requires a narrow climate range to produce grapes of suitable quality for premium wine production.In this thesis, impacts of climate change on winegrape growing conditions across the Western Australian wine regions were spatially and temporally examined by utilising fine resolution downscaled climate projections. Relationships between climate variation and grape maturity or key quality attributes of Cabernet Sauvignon, Shiraz and Chardonnay were modelled from measured fruit and climate data along a natural climate gradient encompassing a 5°C range in winegrape growing season average temperature. Potential future climate change impacts on grape quality were quantitatively evaluated by driving the grape quality models with the downscaled climate projections.Analyses of climate conditions for winegrape growth were carried out under future climate projections for the Western Australian wine regions. A total of 10 global climate models forced with an A2 emission scenario were downscaled. Of these models, the MEDRES Miroc3.2 and CSIRO Mk3.5 climate models, which indicated the low and high warming ranges (projections of these models will be referred as low and high range warming, hereafter) across the study regions, were selected to take into account the uncertainty of future climate change for impact assessment. Our results indicate increasingly warmer and drier climate conditions for the Western Australian wine regions. The current October to April average temperature (averaged across the regions) is projected to be 0.5°C to 1.5°C warmer by 2030, respectively. The magnitude of the warming will likely be uneven across the regions. For example, 0.1 to 0.3°C higher average temperature during October to April period has been projected for the northern regions than the southern regions by 2030, depending on the warming ranges. On the other hand, rainfall is projected to decrease across the regions under the future scenario we assessed in this study. By 2030, annual rainfall, averaged across the regions, is projected to decline by 5 to 8%, respectively, under the low and high warming ranges of climate change under the A2 emission scenario. Among seasons, the greatest decline in rainfall is projected to occur during spring. On average, up to 8% and 19% decline in spring rainfall is projected respectively under the low and high warming ranges by 2030.The magnitude of these changes are projected to increase as time progresses. For example, by 2070, averaged across the study regions, our modelling results show current mean temperature during October to April is projected to be between 1.1°C and 3.9°C warmer, but the annual rainfall is likely to be 15 to 24% lower than the current climate averages (1975 to 2005) under the A2 scenario.Maturity dates of the studied varieties are projected to advance asymmetrically across the study regions. For example, Cabernet Sauvignon may reach 22 °Brix total soluble solid maturity about 4 and 7 days earlier respectively for the northern and the southern regions by 2030 under the low warming range. Our results also indicate maturity date shifting a further 8 and 18 days earlier by 2070 for the northern and the southern regions respectively under the same warming range. Patterns of this maturity date shifting is likely to be similar under the high warming range. However, the magnitude of advancement is projected to be doubled.If no adaptive measures are implemented future climate change will likely reduce wine quality due to declining concentrations of berry anthocyanins and acidity under a warmer climate. The reductions of berry quality attributes are likely to be more pronounced in the warmer northern wine regions compared to the cooler southern regions. For example, Cabernet Sauvignon current median anthocyanins concentration is projected to decline by about 12% and 33% for the warmer northern regions, and about 6 to 18% for the cooler southern wine regions respectively by 2030 and 2070 under the high warming range. In contrast, the maximum decline in Cabernet Sauvignon anthocyanin concentration under the lower warming range is projected to be small, up to 5% for the cooler southern and up to 8% for the warmer northern regions by 2070. Shiraz anthocyanins concentration decrease pattern is similar to that of Cabernet Sauvignon, however, our modelling indicates the magnitude is smaller, with maximum of 18% for Swan District and about 11% for the southern regions by 2070 under the high warming range.Modelled impacts of climate change on grape titratable acidity are also region and variety specific. Among the varieties studied, Chardonnay exhibits the highest decline in median titratable acidity across the regions (17% for the Margaret River and 42% for the Swan District regions), followed by Shiraz (7% for the Margaret River and 15% for the Peel regions) and Cabernet Sauvignon (no change for Blackwood and 12% for the Swan District regions) by 2070 under high climate warming. On the other hand, the median titratable acidity levels are less impacted by low warming scenario (maximum decline is 4% for Shiraz only by 2070).Under the future warming scenarios studied in this thesis currently established wine regions and wine styles across the Western Australian wine regions are likely to be affected to the extent that some regions may not be conducive to premium wine production, while for some regions changing the variety may be the only option to adapt to the climate change. For example, by 2070, under high warming range Swan District, Perth Hills, and some parts of the Peel and Geographe regions are projected to be suited more to producing fortified wines or table grapes due to high average growing season temperature (>24°C). In this future climate the present cool climate southern regions are likely to have the same climate conditions that currently prevail in the warmer Swan District. Apparent differences in currently planted varieties between the cooler southern and warmer northern regions clearly indicate the need to adapt to the warming climate in the southern wine regions.Analysis of other potential factors that influence viticulture such as frequency of hot days, vapour pressure deficit and disease pressure were examined. The results indicated that winegrape fungal disease pressure will likely decrease across the regions due to the declining rainfall, potentially lessening the need for spraying during the growing season. On the other hand, there will likely be increased frequency of hot days and elevated vapour pressure deficit. The impacts of these, combined with the decreasing rainfall during growing season will potentially drive irrigation demand higher requiring altered water management under climate change.Climatically, most of the Western Australian wine regions are known as premium wine producing areas. The results from this study indicate potential challenges of climate change for the Western Australian wine industry. Under the future climate scenarios examined, some currently warmer regions may become less suitable for premium quality wines due to the increased temperature, which is projected to be out of the optimum temperature range for premium wine production. For most of the other regions, the challenge will likely be a decreased grape quality required to produce premium wine with the current varieties. Suitable adaptation strategies may be required to maintain the current market reputation. Furthermore, the warmer and drier conditions under climate change is likely to necessitate revised water management across the wine growing regions, especially some regions which are already limited by available water for grape production. However, the magnitude of the impacts is projected to be dependent upon the magnitude of future climate change.
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Jones, Bevan Keeley. "Learning words and syntactic cues in highly ambiguous contexts." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/15959.
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The cross-situational word learning paradigm argues that word meanings can be approximated by word-object associations, computed from co-occurrence statistics between words and entities in the world. Lexicon acquisition involves simultaneously guessing (1) which objects are being talked about (the ”meaning”) and (2) which words relate to those objects. However, most modeling work focuses on acquiring meanings for isolated words, largely neglecting relationships between words or physical entities, which can play an important role in learning. Semantic parsing, on the other hand, aims to learn a mapping between entire utterances and compositional meaning representations where such relations are central. The focus is the mapping between meaning and words, while utterance meanings are treated as observed quantities. Here, we extend the joint inference problem of word learning to account for compositional meanings by incorporating a semantic parsing model for relating utterances to non-linguistic context. Integrating semantic parsing and word learning permits us to explore the impact of word-word and concept-concept relations. The result is a joint-inference problem inherited from the word learning setting where we must simultaneously learn utterance-level and individual word meanings, only now we also contend with the many possible relationships between concepts in the meaning and words in the sentence. To simplify design, we factorize the model into separate modules, one for each of the world, the meaning, and the words, and merge them into a single synchronous grammar for joint inference. There are three main contributions. First, we introduce a novel word learning model and accompanying semantic parser. Second, we produce a corpus which allows us to demonstrate the importance of structure in word learning. Finally, we also present a number of technical innovations required for implementing such a model.
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Meinhardt, Llopis Enric. "Morphological and statistical techniques for the analysis of 3D images." Doctoral thesis, Universitat Pompeu Fabra, 2011. http://hdl.handle.net/10803/22719.
Full textAbstract:
Aquesta tesi proposa una estructura de dades per
emmagatzemar imatges tridimensionals. L'estructura da dades té
forma d'arbre i codifica les components connexes dels conjunts de
nivell de la imatge. Aquesta estructura és la eina bàsica per
moltes aplicacions proposades: operadors morfològics
tridimensionals, visualització d'imatges mèdiques, anàlisi
d'histogrames de color, seguiment d'objectes en vídeo i detecció
de vores. Motivada pel problema de la completació de vores, la
tesi conté un estudi de com l'eliminació de soroll mitjançant variació
total anisòtropa es pot fer servir per calcular conjunts de
Cheeger en mètriques anisòtropes. Aquests conjunts de Cheeger
anisòtrops es poden utilitzar per trobar òptims globals d'alguns
funcionals per completar vores. També estan relacionats amb
certs invariants afins que s'utilitzen en reconeixement
d'objectes, i en la tesi s'explicita aquesta relació.This thesis proposes a tree data structure to encode the connected components of level sets of 3D images. This data structure is applied as a main tool in several proposed applications: 3D morphological operators, medical image visualization, analysis of color histograms, object tracking in videos and edge detection. Motivated by the problem of edge linking, the thesis contains also an study of anisotropic total variation denoising as a tool for computing anisotropic Cheeger sets. These anisotropic Cheeger sets can be used to find global optima of a class of edge linking functionals. They are also related to some affine invariant descriptors which are used in object recognition, and this relationship is laid out explicitly.
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Aqeeli, Mohammed Ali M. "Microwave oscillator with phase noise reduction using nanoscale technology for wireless systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/microwave-oscillator-with-phase-noise-reduction-using-nanoscale-technology-for-wireless-systems(46287d2a-bc90-4cee-b893-ccf6a3b0747f).html.
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This thesis introduces, for the first time, a novel 4-bit, metal-oxide-metal (MOM) digital capacitor switching array (MOMDCSA) which has been implemented into a wideband CMOS voltage controlled oscillator (VCO) for 5 GHz WiMAX/WLAN applications. The proposed MOMDCSA is added both in series and parallel to nMOS varactors. For further gain linearity, a wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to four nMOS varactor pairs, each of which is biased at a different voltage. Thus, VCO tuning gain reduces and optimal phase noise variation is obtained across a wide range of frequencies. Based on this premise, a wideband VCO is achieved with low phase noise variation of less than 4.7 dBc/Hz. The proposed VCO has been designed using UMC 130 nm CMOS technology. It operates from 3.45 GHz to 6.23 GHz, with a phase noise of -133.80 dBc/Hz at a 1 MHz offset, a figure of merit (FoM) of -203.5 dBc/Hz. A novel microstrip low-phase noise oscillator is based on a left-handed (LH) metamaterial bandpass filter which is embedded in the feedback loop of the oscillator. The oscillator is designed at a complex quality factor Qsc peak frequency, to achieve excellent phase noise performance. At a centre frequency of 2.05 GHz, the reported oscillator demonstrates, experimentally, a phase noise of -126.7 dBc/Hz at a 100 kHz frequency offset and a FoM of -207.2 dBc/Hz at a 1 MHz frequency offset. The increasing demands have been placed on the electromagnetic compatibility performance of VCO devices is crucial. Therefore, this thesis extends the potential of highly flexible and conductive graphene laminate to the application of electromagnetic interference (EMI) shielding. Graphene nanoflake-based conductive ink is printed on paper, and then it is compressed to form graphene laminate with a conductivity of 0.43×105 S/m. Shielding effectiveness is experimentally measured at above 32 dB as being between 12GHz and 18GHz, even though the thickness of the graphene laminate is only 7.7µm. This result demonstrates that graphene has great potential for offering lightweight, low-cost, flexible and environmentally friendly shielding materials which can be extended to offering required shielding from electromagnetic interference (EMI), not only for VCO phase noise optimisation, but also for sensitive electronic devices.
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Chagas, Rebeca Meirelles das. "Estatística para alunos do 6º ano do ensino fundamental: um estudo dos conceitos mobilizados na resolução de problemas." Pontifícia Universidade Católica de São Paulo, 2010. https://tede2.pucsp.br/handle/handle/11444.
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Previous issue date: 2010-05-11Secretaria da Educação do Estado de São Paulo
This study aims to identify the perception of variability and the level of reasoning about this peculiarity, with students of the sixth year at basic education at a state school in Cotia. We discussed what are the concepts and procedures deployed when they resolve issues that involve reading, interpretation and construction of graphs. In particular, diagnose which operative invariants related to the notion of variability that these students mobilized in these activities. As theoretical references, we consider the levels of understanding graphical mobilized by students who are solving problems in statistical context. We also considered the theory of Conceptual Fields seeking to identify the operational invariants by observing the students in situations of problem solving. We performed a qualitative research, with application of a diagnostic instrument, with voluntary participation by two pairs of students. The results pointed to the difficulties of students in reading, interpreting and constructing graphs in specific situations, such as graphs with non-unit scales and null often. For calculating the range, the results showed a stable procedure, especially on the part of one of the pairs studied, in other words, a possible operational invariant, the confusion between the variable frequency and the variable
O presente trabalho tem como objetivo identificar a percepção da variabilidade e o nível de raciocínio sobre essa característica, junto a alunos do sexto ano do Ensino Fundamental de uma escola pública estadual de Cotia. Discutimos quais são os conceitos e procedimentos mobilizados quando estes resolvem questões que envolvem leitura, interpretação e construção de gráficos. Particularmente, diagnosticar quais invariantes operatórios relacionados à noção de variabilidade que estes alunos mobilizaram nessas atividades. Como referências teóricas, consideramos os níveis de compreensão gráfica mobilizados pelos alunos em situação de resolução de problemas em contexto estatístico. Consideramos também a teoria dos Campos Conceituais, buscando identificar os invariantes operatórios por meio da observação dos alunos em situações de resolução de problemas. Foi realizada uma pesquisa qualitativa, com aplicação de um instrumento diagnóstico, com participação voluntária de duas duplas de alunas. Os resultados apontaram para as dificuldades dos alunos na leitura, interpretação e construção de gráficos em situações específicas, como gráficos com escalas não unitárias e o com freqüência nula. Quanto ao cálculo da amplitude, os resultados mostraram um procedimento estável, por parte principalmente de uma das duplas pesquisadas, ou seja, um possível invariante operatório, a confusão entre freqüência da variável e a variável
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Yeo, Ronald A., Sephira G. Ryman, den Heuvel Martijn P. van, Reus Marcel A. de, Rex E. Jung, Jessica Pommy, Andrew R. Mayer, et al. "Graph Metrics of Structural Brain Networks in Individuals with Schizophrenia and Healthy Controls: Group Differences, Relationships with Intelligence, and Genetics." Cambridge University Press, 2016. https://tud.qucosa.de/id/qucosa%3A70691.
Full textAbstract:
Objectives: One of the most prominent features of schizophrenia is relatively lower general cognitive ability (GCA). An emerging approach to understanding the roots of variation in GCA relies on network properties of the brain. In this multi-center study, we determined global characteristics of brain networks using graph theory and related these to GCA in healthy controls and individuals with schizophrenia.
Methods: Participants (N = 116 controls, 80 patients with schizophrenia) were recruited from four sites. GCA was represented by the first principal component of a large battery of neurocognitive tests. Graph metrics were derived from diffusion-weighted imaging.
Results: The global metrics of longer characteristic path length and reduced overall connectivity predicted lower GCA across groups, and group differences were noted for both variables. Measures of clustering, efficiency, and modularity did not differ across groups or predict GCA. Follow-up analyses investigated three topological types of connectivity—connections among high degree “rich club” nodes, “feeder” connections to these rich club nodes, and “local” connections not involving the rich club. Rich club and local connectivity predicted performance across groups. In a subsample (N = 101 controls, 56 patients), a genetic measure reflecting mutation load, based on rare copy number deletions, was associated with longer characteristic path length.
Conclusions: Results highlight the importance of characteristic path lengths and rich club connectivity for GCA and provide no evidence for group differences in the relationships between graph metrics and GCA.