Thèses : « Complex rank »

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Entova, Aizenbud Inna. « Schur Weyl duality in complex rank ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104601.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mathematics, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 207-208).
This thesis gives an analogue to the classical Schur-Weyl duality in the setting of Deligne categories. Given a finite-dimensional unital vector space V (i.e. a vector space V with a distinguished non-zero vector 1) we give a definition of a complex tensor power of V. This is an Ind-object of the Deligne category Rep(St) equipped with a natural action of gl(V). This construction allows us to describe a duality between the abelian envelope of the category Rep(St) and a localization of the category Op/t,v (the parabolic category 0 for gl(V) associated with the pair (V, 1)). In particular, we obtain an exact contravariant functor SWt from the category Repab(St) (the abelian envelope of the category Rep(St)) to a certain quotient of the category Op/t v. This quotient, denoted by 0 p/t v, is obtained by taking the full subcategory of Op/t v consisting of modules of degree t, and localizing by the subcategory of finite dimensional modules. It turns out that the contravariant functor SWt makes Op/t v a Serre quotient of the category Repab(St)OP, and the kernel of SWt can be explicitly described. In the second part of this thesis, we consider the case when V = C[infinity] . We define the appropriate version of the parabolic category 0 and its localization, and show that the latter is equivalent to a "restricted" inverse limit of categories Op/t1CN with N tending to infinity. The Schur-Weyl functors SWt,CN then give an anti-equivalence between the category Op[infinity]/t C[infinity]and the category Repab(Se). This duality provides an unexpected tensor structure on the category Op[infinity]/t C[infinity].
by Inna Entova Aizenbud.
Ph. D.

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FENU, CATERINA. « Applications of low-rank approximation : complex networks and inverse problems ». Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266590.

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The use of low-rank approximation is crucial when one is interested in solving problems of large dimension. In this case, the matrix with reduced rank can be obtained starting from the singular value decomposition considering only the largest components. This thesis describes how the use of the low-rank approximation can be applied both in the analysis of complex networks and in the solution of inverse problems. In the first case, it will be explained how to identify the most important nodes or how to determine the ease of traveling between them in large-scale networks that arise in many applications. The use of low-rank approximation is presented both for undirected and directed networks, whose adjacency matrices are symmetric and nonsymmetric, respectively. As a second application, we propose how to identify inhomogeneities in the ground or the presence of conductive substances. This survey is addressed with the aid of electromagnetic induction measurements taken with a ground conductivity meter. Starting from electromagnetic data collected by this device, the electrical conductivity profile of the soil is reconstructed with the aid of a regularized damped Gauss{Newton method. The inversion method is based on the low-rank approximation of the Jacobian of the function to be inverted.

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Varduhn, Vasco [Verfasser], Ernst [Akademischer Betreuer] Rank et Hans-Joachim [Akademischer Betreuer] Bungartz. « A Parallel, Multi-Resolution Framework for Handling Large Sets of Complex Data, from Exploration and Visualisation to Simulation / Vasco Varduhn. Gutachter : Hans-Joachim Bungartz ; Ernst Rank. Betreuer : Ernst Rank ». München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1052307833/34.

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Pujari, Manisha. « Prévision de liens dans des grands graphes de terrain (application aux réseaux bibliographiques) ». Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD010/document.

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Nous nous intéressons dans ce travail au problème de prévision de nouveaux liens dans des grands graphes de terrain. Nous explorons en particulier les approches topologiques dyadiques pour la prévision de liens. Différentes mesures de proximité topologique ont été étudiées dans la littérature pour prédire l’apparition de nouveaux liens. Des techniques d’apprentissage supervisé ont été aussi utilisées afin de combiner ces différentes mesures pour construire des modèles prédictifs. Le problème d’apprentissage supervisé est ici un problème difficile à cause notamment du fort déséquilibre de classes. Dans cette thèse, nous explorons différentes approches alternatives pour améliorer les performances des approches dyadiques pour la prévision de liens. Nous proposons d’abord, une approche originale de combinaison des prévisions fondée sur des techniques d’agrégation supervisée de listes triées (ou agrégation de préférences). Nous explorons aussi différentes approches pour améliorer les performances des approches supervisées pour la prévision de liens. Une première approche consiste à étendre l’ensemble des attributs décrivant un exemple (paires de noeuds) par des attributs calculés dans un réseau multiplexe qui englobe le réseau cible. Un deuxième axe consiste à évaluer l’apport destechniques de détection de communautés pour l’échantillonnage des exemples. Des expérimentations menées sur des réseaux réels extraits de la base bibliographique DBLP montrent l’intérêt des approaches proposées
In this work, we are interested to tackle the problem of link prediction in complex networks. In particular, we explore topological dyadic approaches for link prediction. Different topological proximity measures have been studied in the scientific literature for finding the probability of appearance of new links in a complex network. Supervided learning methods have also been used to combine the predictions made or information provided by different topological measures. The create predictive models using various topological measures. The problem of supervised learning for link prediction is a difficult problem especially due to the presence of heavy class imbalance. In this thesis, we search different alternative approaches to improve the performance of different dyadic approaches for link prediction. We propose here, a new approach of link prediction based on supervised rank agregation that uses concepts from computational social choice theory. Our approach is founded on supervised techniques of aggregating sorted lists (or preference aggregation). We also explore different ways of improving supervised link prediction approaches. One approach is to extend the set of attributes describing an example (pair of nodes) by attributes calculated in a multiplex network that includes the target network. Multiplex networks have a layered structure, each layer having different kinds of links between same sets of nodes. The second way is to use community information for sampling of examples to deal with the problem of classe imabalance. Experiments conducted on real networks extracted from well known DBLP bibliographic database

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Oreifej, Omar. « Robust Subspace Estimation Using Low-Rank Optimization. Theory and Applications in Scene Reconstruction, Video Denoising, and Activity Recognition ». Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5684.

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In this dissertation, we discuss the problem of robust linear subspace estimation using low-rank optimization and propose three formulations of it. We demonstrate how these formulations can be used to solve fundamental computer vision problems, and provide superior performance in terms of accuracy and running time. Consider a set of observations extracted from images (such as pixel gray values, local features, trajectories...etc). If the assumption that these observations are drawn from a liner subspace (or can be linearly approximated) is valid, then the goal is to represent each observation as a linear combination of a compact basis, while maintaining a minimal reconstruction error. One of the earliest, yet most popular, approaches to achieve that is Principal Component Analysis (PCA). However, PCA can only handle Gaussian noise, and thus suffers when the observations are contaminated with gross and sparse outliers. To this end, in this dissertation, we focus on estimating the subspace robustly using low-rank optimization, where the sparse outliers are detected and separated through the `1 norm. The robust estimation has a two-fold advantage: First, the obtained basis better represents the actual subspace because it does not include contributions from the outliers. Second, the detected outliers are often of a specific interest in many applications, as we will show throughout this thesis. We demonstrate four different formulations and applications for low-rank optimization. First, we consider the problem of reconstructing an underwater sequence by removing the turbulence caused by the water waves. The main drawback of most previous attempts to tackle this problem is that they heavily depend on modelling the waves, which in fact is ill-posed since the actual behavior of the waves along with the imaging process are complicated and include several noise components; therefore, their results are not satisfactory. In contrast, we propose a novel approach which outperforms the state-of-the-art. The intuition behind our method is that in a sequence where the water is static, the frames would be linearly correlated. Therefore, in the presence of water waves, we may consider the frames as noisy observations drawn from a the subspace of linearly correlated frames. However, the noise introduced by the water waves is not sparse, and thus cannot directly be detected using low-rank optimization. Therefore, we propose a data-driven two-stage approach, where the first stage “sparsifies” the noise, and the second stage detects it. The first stage leverages the temporal mean of the sequence to overcome the structured turbulence of the waves through an iterative registration algorithm. The result of the first stage is a high quality mean and a better structured sequence; however, the sequence still contains unstructured sparse noise. Thus, we employ a second stage at which we extract the sparse errors from the sequence through rank minimization. Our method converges faster, and drastically outperforms state of the art on all testing sequences. Secondly, we consider a closely related situation where an independently moving object is also present in the turbulent video. More precisely, we consider video sequences acquired in a desert battlefields, where atmospheric turbulence is typically present, in addition to independently moving targets. Typical approaches for turbulence mitigation follow averaging or de-warping techniques. Although these methods can reduce the turbulence, they distort the independently moving objects which can often be of great interest. Therefore, we address the problem of simultaneous turbulence mitigation and moving object detection. We propose a novel three-term low-rank matrix decomposition approach in which we decompose the turbulence sequence into three components: the background, the turbulence, and the object. We simplify this extremely difficult problem into a minimization of nuclear norm, Frobenius norm, and L1 norm. Our method is based on two observations: First, the turbulence causes dense and Gaussian noise, and therefore can be captured by Frobenius norm, while the moving objects are sparse and thus can be captured by L1 norm. Second, since the object's motion is linear and intrinsically different than the Gaussian-like turbulence, a Gaussian-based turbulence model can be employed to enforce an additional constraint on the search space of the minimization. We demonstrate the robustness of our approach on challenging sequences which are significantly distorted with atmospheric turbulence and include extremely tiny moving objects. In addition to robustly detecting the subspace of the frames of a sequence, we consider using trajectories as observations in the low-rank optimization framework. In particular, in videos acquired by moving cameras, we track all the pixels in the video and use that to estimate the camera motion subspace. This is particularly useful in activity recognition, which typically requires standard preprocessing steps such as motion compensation, moving object detection, and object tracking. The errors from the motion compensation step propagate to the object detection stage, resulting in miss-detections, which further complicates the tracking stage, resulting in cluttered and incorrect tracks. In contrast, we propose a novel approach which does not follow the standard steps, and accordingly avoids the aforementioned difficulties. Our approach is based on Lagrangian particle trajectories which are a set of dense trajectories obtained by advecting optical flow over time, thus capturing the ensemble motions of a scene. This is done in frames of unaligned video, and no object detection is required. In order to handle the moving camera, we decompose the trajectories into their camera-induced and object-induced components. Having obtained the relevant object motion trajectories, we compute a compact set of chaotic invariant features, which captures the characteristics of the trajectories. Consequently, a SVM is employed to learn and recognize the human actions using the computed motion features. We performed intensive experiments on multiple benchmark datasets, and obtained promising results. Finally, we consider a more challenging problem referred to as complex event recognition, where the activities of interest are complex and unconstrained. This problem typically pose significant challenges because it involves videos of highly variable content, noise, length, frame size ... etc. In this extremely challenging task, high-level features have recently shown a promising direction as in [53, 129], where core low-level events referred to as concepts are annotated and modeled using a portion of the training data, then each event is described using its content of these concepts. However, because of the complex nature of the videos, both the concept models and the corresponding high-level features are significantly noisy. In order to address this problem, we propose a novel low-rank formulation, which combines the precisely annotated videos used to train the concepts, with the rich high-level features. Our approach finds a new representation for each event, which is not only low-rank, but also constrained to adhere to the concept annotation, thus suppressing the noise, and maintaining a consistent occurrence of the concepts in each event. Extensive experiments on large scale real world dataset TRECVID Multimedia Event Detection 2011 and 2012 demonstrate that our approach consistently improves the discriminativity of the high-level features by a significant margin.
Ph.D.
Doctorate
Electrical Engineering and Computing
Engineering and Computer Science
Computer Engineering

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Lebiez, Judith. « 'Sie rief mich aus der Nacht' : the birth complex in Nietzsche and Wagner ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/278675.

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This thesis addresses the role of the birth complex in Friedrich Nietzsche’s philosophy and in Richard Wagner’s operas. I see the birth complex as characterised by a dialectical relation between flesh and light, which is itself polarised by the tension between desire and anxiety. A structural determinant of the human relation to the world, this complex in my argument is of special importance for understanding the roles given to and assumed by women. Wagner gave the birth complex its first comprehensive elaboration through his operas. This, I contend, is the aspect of Wagner’s work that Nietzsche in his writings particularly reacted to through the ambivalent fascination it awakened in him. I argue that, even after Nietzsche’s break from Wagner, the birth complex remains central in his philosophy. The primary reference I build on here is Otto Rank’s theory of birth trauma, as set out in Das Trauma der Geburt (1924). To me, Rank’s theorisation of the trauma of birth is a translation into psychoanalytic language of Nietzsche’s philosophy, which itself arose with a translation into philosophical language of Wagner’s operas. In this thesis I build especially on Rank’s formulation of the tension between desire and anxiety and on his suggestions concerning the causes of the undoing of women. However, Rank did not take into account what I contend is a key aspect of both Nietzsche’s and Wagner’s work: the role of light in its dialectical relation with the flesh. By flesh I mean the interiority of the mother’s body and, by extension, the human body insofar as it is conceived through its relation to the maternal body. In the first main section of my PhD, I propose a theoretical understanding of the birth complex through an analysis of Nietzsche’s philosophy. I start with his writings pro and contra Wagner, showing that what Nietzsche primarily sees in Wagner’s operas is the birth complex. I then go on to argue that Nietzsche’s philosophy of life and of creativity is an exploration of the ways in which birth could be overcome. The second main section of my PhD is dedicated to Wagner, with largely text-based readings of three operas. I first discuss the extent to which death in Der fliegende Holländer and in the Freudian conception of the death drive is a mask for birth. I then tackle Tristan und Isolde and its famous celebration of night and death, in order to investigate whether love can be reduced to the birth complex. The last chapter of this section presents a close analysis of Das Rheingold and especially of its first scene and of Wagner’s indications on lighting. In a third and shorter section, I show that Hugo von Hofmannsthal’s and Richard Strauss’s Elektra pursued and reviewed this fundamental preoccupation of Nietzsche’s and Wagner’s work in proposing a further formulation of the birth complex that incorporates the scene of matricide. Finally, as a coda to the thesis, I explore the extent to which the uses of stage lighting pioneered by Adolphe Appia have been coming to terms with the birth complex.

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Albergante, L. « A PETRI NET MODEL OF LIVER RESPONSE TO VISCERAL LEISHMANIASIS : SELF-REGULATION AND COMPLEX INTERPLAY IN THE VERTEBRATE IMMUNE SYSTEM ». Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150085.

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Visceral leishmaniasis (also called "Kala-azar") is a widespread disease, which is usually fatal in the absence of treatment. Characteristic of the liver immune response to leishmaniasis is a type of inflammation (granulomatous inflammation) that leads to the formation of "granulomas". A granuloma provides a very interesting micro-environment, which is maintained by the coordination of many cells of the immune system. Due to the complexity of the immune response, only a limited amount of modeling work exists in the context of granulomatous infection, and most of the current models focus only on the formation stage of granulomas. The primary goal of this thesis is to gain insights into the process of formation and development of a granuloma. To this end, we built a model of the granuloma formation and resolution in the liver using stochastic Petri nets, and performed several in silico experiments to study the nature of the immune response to leishmaniasis, possible therapeutic options, and the role of the cells involved. Additionally, the building of the model is extensively documented, and the most important qualitative and quantitative assumptions are referenced and discussed, with the aim of presenting a “conceptual framework” to be used when facing similar problems. The model is validated against available biological data, and its robustness is assessed using sensitivity analysis.

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Bain, Raoul Harley. « The elucidation of the Rana livida complex ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq40881.pdf.

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Eastwood, S. J. « Hybrid LES – RANS of complex geometry jets ». Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598741.

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A promising technique for exploring jet flows is large eddy simulation (LES). However for jet LES a number of key unanswered questions remain. These include the sensitivity of solutions to the numerical scheme, subgrid scale (SGS) model and inlet conditions. Results show that for more dissipative, robust solvers often found in industry, SGS model omission can give useful results. Solutions which use no SGS model are called Numerical LES (NLES). For less dissipative codes, solutions are found to be relatively insensitive to the choice of SGS model. An industrial based solver is selected and validated further by making acoustic and hot jet predictions using the NLES approach. Encouraging agreement with measurements is shown. To relieve computational cost, the near wall modelling issue is also addressed. A novel method is used to blend a near wall Reynolds averaged Navier Stokes (RANS) method with NLES used away from the wall. Blending between the two regions makes use of the Hamilton Jacobi equation. Real engines have high bypass ratio nozzles and so the flow through these is explored. Predictions are made using the hybrid RANS-NLES strategy. Different case set ups are simulated including hot and cold jets and a range of meshes from 6 x 10⁶ to 50 x 10⁶ cells. For all the meshes, results show encouraging agreement with measurements. The near wall RANS modelling is helpful in preventing non-physical separation from curved surfaces highlighting the usefulness of the hybrid approach. A pylon, which attaches the engine to the wing, is shown to influence the flow development, having a significant impact on peak turbulence levels and spreading rates. Wakes, simulating those shed by upstream turbomachinery, are included in the nozzle geometry. The wakes are introduced using a body force model which prevents the need to explicitly model blade geometry. The results have demonstrated that real geometry effects are particularly influential and should be taken into account when moving towards real engine simulations.

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Colon, Laetitia. « L'hybridogenèse dans le complexe Rana klepton esculenta : apports des marqueurs génétiques ». Lyon 1, 2004. http://www.theses.fr/2004LYO10143.

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Cette étude porte sur le complexe hybridogénétique de la grenouille verte Rana klepton esculenta. R. Esculenta résulte d'un croisement entre R. Lessonae et R. Ridibunda. Théoriquement, à chaque méiose, chez les R. Esculenta, le génome lessonae est éliminé, et le génotype hybride est restauré par croisement avec un mâle R. Lessonae. Il y a donc transmission clonale de l'hémigénome ridibunda et formation d'hémiclones. Le déterminisme du sexe fait qu'il y a production d'autant de mâles que de femelles hybrides. Les mâles sont cependant considérés comme n'intervenant pas dans la reproduction. Contrairement à l'attendu théorique, nos études génétiques (enzymologie et microsatellites) montrent que de nombreux têtards R. Ridibunda sont produits. Ces têtards résultent manifestement de croisement entre femelles R. Esculenta et mâles R. Esculenta. Enfin, nos résultats suggèrent que les R. Ridibunda néoformés peuvent participer à la reproduction, permettant ainsi de générer de nouveaux hémiclones

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Cousin, Gaël. « Connexions plates logarithmiques de rang deux sur le plan projectif complexe ». Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00779098.

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Dans cette thèse on étudie les propriétés des connexions plates logarithmiques de rang 2 et leurs projectifies qui sont des feuilletages de Riccati, principalement sur le plan projectif. L'invariant principal d'un tel objet est sa représentation de monodromie, qui est une représentation vers SL2(C) ou PSL2(C) du groupe fondamental du complémentaire de son lieu polaire. Dans un premier temps, on étudie la propriété, pour un feuilletage de Riccati sur P2, d'être obtenu en tirant un en arrière un feuilletage de Riccati au dessus d'une courbe. Ensuite on s'intéresse aux feuilletages de Riccati qui ne sont pas construits de cette maniere et qui peuvent être obtenus a partir d'une solution algébrique de l'équation de Painleve VI. Nous les classons par orbites sous le groupe de Galois de Q ̄ sur Q. Finalement, on s'int ́eresse aux feuilletages transversalement projectifs : ces feuilletages s'obtiennent par restriction de feuilletages de Riccati a' des sections de leurs P1-fibres sous-jacents. On s'interesse particulierement aux feuilletages modulaires de Hilbert, dont on decrit assez finement la structure transverse. On conclut notre travail par l'exhibition de modeles birationnels sur P2 pour certains feuilletages modulaires de Hilbert.

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Saak, Jens, et Stephan Schlömer. « RRQR-MEX - Linux and Windows 32bit MATLAB MEX-Files for the rank revealing QR factorization ». Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-201000022.

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The rank revealing QR decomposition is a special form of the well known QR decomposition of a matrix. It uses specialized pivoting strategies and allows for an easy and efficient numerical rank decision for arbitrary matrices. It is especially valuable when column compression of rectangular matrices needs to be performed. Here we provide documentation and compilation instructions for a MATLAB MEX implementation of the RRQR allowing the easy usage of this decomposition inside the MATLAB environment.

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Baï, Siau Wei. « Caractérisation fonctionnelle du complexe Nup107 : un sous-complexe protéique du pore nucléaire chez la levure Schizosaccharomyces pombe ». Paris 11, 2004. http://www.theses.fr/2004PA112251.

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Chez les eucaryotes, les pores nucléaires (NPC) contrôlent tous les échanges de macromolécules entre le noyau et le cytoplasme. Les caractéristiques générales de la structure du NPC et ses principaux constituants (appelés nucléoporines ou Nups) ont été conservés au cours de l'Evolution Contrairement au NPC de S. Cerevisiae et des Vertébrés, il existe actuellement peu de données sur le NPC chez S. Pombe. Par homologie de séquence avec les Nups du complexe Nup84 de S. Cerevisiae, j'ai nouvellement identifié le complexe Nup107 chez S. Pombe. En dépit des différences de viabilité des souches délétées pour ces Nups entre ces deux levures, l'analyse phénotypique des souches mutantes suggère que l'implication du complexe Nup84/107, dans la distribution des NPC au sein de l'enveloppe nucléaire ainsi que dans l'export nucléaire des ARNm, a été conservée au cours de l'Evolution. Par ailleurs, certaines des souches S. Pombe présentent des défauts de mitoses (condensation anormale de la chromatine, défauts de ségrégation des chromosomes et de cytocinèse/septation), suggérant un rôle additionnel du complexe Nup107 en mitose. Mes travaux ont montré l'existence d'une interaction génétique entre le complexe Nup107 et la petite GTPase Ran, suggérant que l'implication du complexe Nup107 dans les mécanismes de mitose pourrait être liée aux fonctions de Ran en mitose. Ainsi bien que le complexe Nup107 chez S. Pombe ne soit pas localisé aux kinétochores comme cela a été montré chez l'humain, mes travaux mettent en évidence la participation du complexe Nup84/107 au processus de mitose et la conservation au cours de l'Evolution du lien étroit entre le complexe Nup84/107 et Ran
The overall organization of the nuclear pore complexes (NPC) has been evolutionary conserved. Yet variations in organisms likely provide important clues to NPC functions. While most NPC proteins (nucleoporins or Nups) have been identified in S. Cerevisiae and vertebrates, few nucleoporins have been characterized in the yeast Schizosaccharomyces pombe. During my PhD, through sequence homology with S. Cerevisiae, I have identified and further functionally characterized 6 novel S. Pombe nucleoporins. Biochemical approaches have confirmed the organization of these Nups within conserved NPC subcomplexes. While examination of the S. Pombe deletion mutants revealed different viability phenotype as compared to their S. Cerevisiae orthologues, functional studies indicated that the involvement of this complex in NPC distribution and mRNA export has been partly conserved between these highly divergent yeasts. Unexpectedly microscopic analyses of the S. Pombe mutants showed additional cell division defects (spindles, chromosome segregation and septation) reminiscent to some GTPase Ran-cycle mutants. Consistently I further showed a specific functional link between the SpNup107 complex and the Ran pathway. During mitosis, the Human Nup107 complex colocalizes with kinetochores suggesting an as yet unidentified evolutionary conserved role of these Nups in mitosis, even though this feature does not seem to be conserved in S. Pombe. These differences between yeast S. Pombe and vertebrates could be associated to some specificity related to closed versus opened mitosis. My work has thus provided additional clues of the involvement of the Nup107 complex in cell division mechanisms

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Lan, Ma. « Abschätzungen von Lösungen der [delta bar]-Gleichung auf streng q-konvexen Mengen mit nicht glattem Rand ». Bonn : [s.n.], 1989. http://catalog.hathitrust.org/api/volumes/oclc/20436892.html.

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Covanov, Svyatoslav. « Algorithmes de multiplication : complexité bilinéaire et méthodes asymptotiquement rapides ». Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0057/document.

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Depuis 1960 et le résultat fondateur de Karatsuba, on sait que la complexité de la multiplication (d’entiers ou de polynômes) est sous-quadratique : étant donné un anneau R quelconque, le produit sur R[X] des polynômes a_0 + a_1 X et b_0 + b_1 X, pour tous a_0, a_1, b_0 et b_1 dans R, peut être calculé en seulement trois et non pas quatre multiplications sur R : (a_0 + a_1 X)(b_0 + b_1 X) = m_0 + (m_2 - m_0 - m_1)X + m_1 X^2, avec les trois produits m_0 = a_0b_0, m_1 = a_1b_1 et m_2 = (a_0 + a_1)(b_0 + b_1). De la même manière, l’algorithme de Strassen permet de multiplier deux matrices 2nx2n en seulement sept produits de matrices nxn. Les deux exemples précédents tombent dans la catégorie des applications bilinéaires : des fonctions de la forme Phi : K^m x K^n -> K^l, pour un corps donné K, linéaires en chacune des deux variables. Parmi les applications bilinéaires les plus classiques, on trouve ainsi la multiplication de polynômes, de matrices, ou encore d’éléments d’extensions algébriques de corps finis. Étant donnée une application bilinéaire Phi, calculer le nombre minimal de multiplications nécessaires au calcul de cette application est un problème NP-difficile. L'objectif de cette thèse est de proposer des algorithmes minimisant ce nombre de multiplications. Deux angles d'attaques ont été suivis. Un premier aspect de cette thèse est l'étude du problème du calcul de la complexité bilinéaire sous l'angle de la reformulation de ce problème en termes de recherche de sous-espaces vectoriels de matrices de rang donné. Ce travail a donné lieu à un algorithme tenant compte de propriétés intrinsèques aux produits considérés tels que les produits matriciels ou polynomiaux sur des corps finis. Cet algorithme a permis de trouver toutes les décompositions possibles, sur F_2, pour le produit de polynômes modulo X^5 et le produit de matrices 3x2 par 2x3. Un autre aspect de ma thèse est celui du développement d’algorithmes asymptotiquement rapides pour la multiplication entière. Une famille particulière d'algorithmes récents ont été proposés suite à un article de Fürer publié en 2007, qui proposait un premier algorithme, reposant sur la transformée de Fourier rapide (FFT) permettant de multiplier des entiers de n bits en O(n log n 2^{O(log^* n)}), où log^* est la fonction logarithme itéré. Dans cette thèse, un algorithme dont la complexité dépend d'une conjecture de théorie des nombres est proposé, reposant sur la FFT et l'utilisation de premiers généralisés de Fermat. Une analyse de complexité permet d'obtenir une estimation en O(n log n 4^{log^* n})
Since 1960 and the result of Karatsuba, we know that the complexity of the multiplication (of integers or polynomials) is sub-quadratic: given a ring R, the product in R[X] of polynomials a_0 + a_1 X and b_0 + b_1 X, for any a_0, a_1, b_0 and b_1 in R, can be computed with three and not four multiplications over R: (a_0 + a_1X)(b_0 + b_1X) = m_0 + (m_2 - m_0 - m_1)X + m_1X^2, with the three multiplications m_0 = a_0b_0, m_1 = a_1b_1 et m_2 = (a_0 + a_1)(b_0 + b_1). In the same manner, Strassen's algorithm allows one to multiply two matrices 2nx2n with only seven products of matrices nxn. The two previous examples fall in the category of bilinear maps: these are functions of the form Phi : K^m x K^n -> K^l, given a field K, linear in each variable. Among the most classical bilinear maps, we have the multiplication of polynomials, matrices, or even elements of algebraic extension of finite fields. Given a bilinear map Phi, computing the minimal number of multiplications necessary to the evaluation of this map is a NP-hard problem. The purpose of this thesis is to propose algorithms minimizing this number of multiplications. Two angles of attack have been studied. The first aspect of this thesis is to study the problem of the computation of the bilinear complexity under the angle of the reformulation of this problem in terms of research of matrix subspaces of a given rank. This work led to an algorithm taking into account intrinsic properties of the considered products such as matrix or polynomial products over finite fields. This algorithm allows one to find all the possible decompositions, over F_2, for the product of polynomials modulo X^5 and the product of matrices 3x2 by 2x3. Another aspect of this thesis was the development of fast asymptotic methods for the integer multiplication. There is a particular family of algorithms that has been proposed after an article by Fürer published in 2007. This article proposed a first algorithm, relying on fast Fourier transform (FFT), allowing one to multiply n-bit integers in O(n log n 2^{O(log^* n)}), where log^* is the iterated logarithm function. In this thesis, an algorithm, relying on a number theoretical conjecture, has been proposed, involving the use of FFT and generalized Fermat primes. With a careful complexity analysis of this algorithm, we obtain a complexity in O(nlog n 4^{log^* n})

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Ould, Sehla Daf. « Les complexes hybridogénétiques des grenouilles vertes méridionales : identification, distribution et adaptation à la temporarité (rana perezi-rana kl. grafi) ». Angers, 2005. http://www.theses.fr/2005ANGE0042.

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L’écologie des grenouilles vertes « méridionales » a été étudiée à travers le prisme de la comparaison des traits d’histoire de vie liés positivement à la fitness des têtards. Ce travail de recherche a consisté en 1) l’identification génétique des grenouilles, 2) l’évaluation de l’apport de la morphométrie dans l’identification morphologique et la mise en évidence de ces limites, 3) la distribution géographique de 5 taxons (R. Ridibunda, R. Lessonae, R. Perezi, esculenta et R. Kl. Grafi dans le sud de la France à travers l’étude de 9 populations et 4) l’étude des processus d’adaptation locales. L’électrophorèse des protéines a permis l’identification taxonomique des grenouilles (marqueurs spécifiques allozymiques) et a mis en évidence la présence de nouveaux allèles pour R. Perezi ; et R. Lessonae. A contrario, aucun trait morphologique des 24 variables et ratios mesurés ne permet de différencier entre les 5 taxons. Les moyennes présentent un chevauchement interspécifique et intraspécifique. En revanche, ce travail a mis en évidence que la variation écotypique masque les variations spécifiques. La présence de R. Lessonae dans le Sud de la France constitue une avancée dans les connaissances de la répartition géographique de cette espèce. De plus, une nouvelle zone de contact entre 2 complexes d’hybridation distincts, les systèmes P-G et L-E a été localisée dans un milieu temporaire dans le sud de la France. Les processus d’adaptation locale ont été mis en évidence par des protocoles expérimentaux permettant la comparaison des performances écologiques (mesure indirecte de la fitness) des taxons du complexe P-G à travers des traits d’histoire de vie comme le développement larvaire, la survie et le poids à la métamorphose dans le contexte de 2 types de milieux : temporaire et permanent. Nous concluons que les taxons de grenouilles vertes présentent des réponses spécifiques au niveau génétique et phénotypique (adaptation locale) aux variations des facteurs abiotiques et biotiques de l’environnement. Les individus de milieux temporaires présentent une meilleure fitness en comparaison avec leurs fratries de milieux permanents dans un contexte de milieu temporaire
The ecology of the“southernmost” green frogs was studied by comparing the life history traits, which were found to be positively related to the fitness of the tadpoles. This research project mainly consisted of 1) the genetic identification of frogs, 2) the evaluation of the contribution of morphometry in the morphological identification and the analyses of these limits, 3) the geographic distribution of five taxa (R. Ridibunda, R. Lessonae, R. Perezi, R. Kl. Esculenta R. Kl. Grafi) in the south of France by studying 9 populations and 4) the study of the local processes of adaptation. The protein electrophoresis allowed the taxonomic identification of the frogs (specific allozymic markers) and the presence of new alleles for R. Perezi: and R. Lessonae was evidenced. On the contrary, of all the 24 variables and ratios measured, no morphological traits made it possible to differentiate between the 5 taxa. The averages indicate an interspecific and intraspecific overlapping. Although, this work clearly highlighted that the ecotypic variations masked the specific variations. The distribution of R. Lessonae in the South of France constitutes an improvement in the knowledge of the geographic distribution of this species. Moreover, one new of contact zone between 2 distinct complexes of hybridization, the P-G and the L–E systems, was localised in a temporary pond in the south of France. The local processes of adaptations were highlighted by experimental protocols which allow the comparison of the ecological performances (indirect measurement of fitness) of the taxa of the complex R. Perezi - R. Kl. Grafi, through life history traits like larval development, survival and weight at metamorphosis in 2 different types of environments: temporary and permanent. We, thus, conclude that the green frog taxa show/demonstrate specifics responses at genetic and phenotypical levels (local adaptation) to the variations of the abiotic and biotic environmental factors. However the tadpoles of the temporary environment present a better fitness when compared with their siblings of permanent environments in context of temporary ponds

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Akin, Cigdem. « Detection Of Species Boundaries In The Rana Ridibunda Complex Of Southwestern Turkey Using Mitochondrial Nd3 Marker ». Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608156/index.pdf.

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Water frogs are one of the most interesting vertebrate groups, showing great diversity and complexity in their reproductive modes, ecology and evolutionary relationships, and with many cryptic species due to high morphological similarity. For many decades, a single species, Rana ridibunda, has been suggested to exist in Turkey. However, the application of new morphometric, molecular and bioacoustic techniques has recently revealed the occurrence of several distinct water frog taxa in Turkey. In this study, 340 bp long mtDNA ND3 region in 195 specimens was sequenced and subjected to phylogenetic analyses to detect geographical structure and species boundaries. Neighbor joining tree, minimum spanning network, SAMOVA and AMOVA were used to understand relationship within and among clades. Population demography was studied through mismatch distribution and neutrality tests. Results indicated that populations in southwestern Turkey show high diversity and strong geographic structuring. In Turkey there are four major maternal lineages, each probably representing a species: Thrace lineage represents Rana ridibunda Pallas 1771 in European Turkey
Ceyhan lineage indicates an unnamed taxon in Cilicia plain
South-central lineage occurs at the Lake District, Antalya, Konya and Karaman provinces and represents Rana caralitana Arikan, 1988
Anatoliaca lineage (occuring in Asiatic Turkey except for central southern Turkey, Rhodes &
Karpathos, northeastern Syria, and probably also Iraq and Transcaucasia) is designated either as Rana cerigensis Beerli, Hotz, Tunner, Heppich, and Uzzell 1994 or as a new subspecies of R. caralitana, based on the degree of reproductive isolation present between the last two lineages.

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Nolin, Guillaume. « Une méthode de couplage RANS/LES zonal pour la simulation instationnaire d'écoulements turbulents complexes ». Paris 6, 2007. http://www.theses.fr/2007PA066714.

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La pertinence des méthodes de couplage RANS/LES zonal pour la simulation instationnaire d’écoulements turbulents est présentée. Les problèmes à résoudre pour mettre en place une stratégie de couplage zonal sont exposés. Parmi ceux-ci deux sont traités. Le premier est l’amélioration des stratégies de couplage zonal afin d’étendre la zone d’influence LES le plus loin possible dans le domaine RANS. La solution proposée consiste en une méthode originale de reconstruction de la viscosité turbulente RANS à partir de champs LES, alliée à une fonction corrigeant le modèle de turbulence RANS. Le second est la génération d’une turbulence réaliste en entrée des domaines LES par enrichissement des solutions RANS, afin de réduire au maximum la taille des domaines LES. Il est résolu en utilisant des conditions d’entrée instationnaire pour la LES reposant sur des bases de données. Ces techniques sont évaluées sur un écoulement autour d’un profil d’aile à grand nombre de Reynolds et à forte incidence
The relevance of the zonal RANS/LES coupling methods for the unsteady simulation of turbulent flows is presented. The problems to be solved in order to develop a strategy of zonal coupling are outlined. Two of these problems are addressed. The first one is the improvement of the strategies of the zonal coupling to extend the area of influence of the LES zone in the RANS zone as far as possible. The proposed solution is based on an original RANS eddy viscosity reconstruction method, combined with a correction for the RANS turbulence model. The second one deals with the generation of a realistic turbulence at the inflow of the LES domains thanks to an enrichment of the RANS solutions, in order to reduce as much as possible the size of the LES domains. This turbulence is generated through LES inflow conditions based on databases. These techniques are applied to the flow around an airfoil at high Reynolds number and high angle of attack

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Ben, Abdallah Rayen. « Statistical signal processing exploiting low-rank priors with applications to detection in Heterogeneous Environment ». Thesis, Paris 10, 2019. http://www.theses.fr/2019PA100076.

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Dans un premier lieu, nous considérons le problème de l'estimation de sous-espace d'un signal d'intérêt à partir d'un jeu de données bruité. Pour ce faire, nous adoptons une approche Bayésienne afin d'obtenir un estimateur minimisant la distance moyenne entre la vraie matrice de projection et son estimée. Plus particulièrement, nous étendons les estimateurs au contexte Gaussien composé pour les sources où l'a priori sur la base sera une loi complexe generalized Bingham Langevin. Enfin, nous étudions numériquement les performances de l'estimateur proposé sur une application de type space time adaptive processing pour un radar aéroporté au travers de données réelles.Dans un second lieu, nous nous intéressons au test de propriété communes entre les matrices de covariance. Nous proposons des nouveaux tests statistiques dans le contexte de matrices de covariance structurées. Plus précisément, nous considérons un signal de rang faible corrompu par un bruit blanc Gaussien additif. Notre objectif est de tester la similarité des composantes principales à rang faible communes à un ensemble de matrices de covariance. Dans un premier temps, une statistique de décision est dérivée en utilisant le rapport de vraisemblance généralisée. Le maximum de vraisemblance n'ayant pas d'expression analytique dans ce cas, nous proposons un algorithme d'estimation itératif de type majoration-minimisation pour pouvoir évaluer les tests proposés. Enfin, nous étudions les propriétés des détecteurs proposés à l'aide de simulations numériques
In this thesis, we consider first the problem of low dimensional signal subspace estimation in a Bayesian context. We focus on compound Gaussian signals embedded in white Gaussian noise, which is a realistic modeling for various array processing applications. Following the Bayesian framework, we derive algorithms to compute both the maximum a posteriori and the so-called minimum mean square distance estimator, which minimizes the average natural distance between the true range space of interest and its estimate. Such approaches have shown their interests for signal subspace estimation in the small sample support and/or low signal to noise ratio contexts. As a byproduct, we also introduce a generalized version of the complex Bingham Langevin distribution in order to model the prior on the subspace orthonormal basis. Numerical simulations illustrate the performance of the proposed algorithms. Then, a practical example of Bayesian prior design is presented for the purpose of radar detection.Second, we aim to test common properties between low rank structured covariance matrices.Indeed, this hypothesis testing has been shown to be a relevant approach for change and/oranomaly detection in synthetic aperture radar images. While the term similarity usually refersto equality or proportionality, we explore the testing of shared properties in the structure oflow rank plus identity covariance matrices, which are appropriate for radar processing. Specifically,we derive generalized likelihood ratio tests to infer i) on the equality/proportionality ofthe low rank signal component of covariance matrices, and ii) on the equality of the signalsubspace component of covariance matrices. The formulation of the second test involves nontrivialoptimization problems for which we tailor ecient Majorization-Minimization algorithms.Eventually, the proposed detection methods enjoy interesting properties, that are illustrated on simulations and on an application to real data for change detection

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Xu, Xianfeng. « Two sides of the plant nuclear pore complex and a potential link between Ran GTPase and plant cell division ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1190050471.

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Jacques, Julien. « Contribution à l'apprentissage statistique à base de modèles génératifs pour données complexes ». Habilitation à diriger des recherches, Université des Sciences et Technologie de Lille - Lille I, 2012. http://tel.archives-ouvertes.fr/tel-00761184.

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Ce mémoire synthétise les activités de recherche que j'ai menées de 2005 à 2012, sur la thématique de l'apprentissage statistique des données complexes, abordée par le biais de modèles probabilistes paramétriques génératifs. Plusieurs types de données complexes sont considérées. Les données issues de populations différentes ont été abordées en proposant des modèles de lien paramétriques entre populations, permettant d'adapter les modèles statistiques d'une population vers l'autre, en évitant une lourde collecte de nouvelles données. Les données de rang, définissant un classement d'objets selon un ordre de préférence, les données ordinales, qui sont des données qualitatives ayant des modalités ordonnées, et les données fonctionnelles, où l'observation statistique consiste en une ou plusieurs courbes, ont également été étudies. Pour ces trois types de données, des modèles génératifs probabilistes ont été définis et utilisés en classification automatique de données multivariées. Enfin les données de grande dimension, que l'on rencontre lorsque le nombre de variables du problème dépasse celui des observations, ont été étudiées dans un cadre de régression. Deux approches, fruits de deux thèses de doctorat que je co-encadre, sont proposés: l'une utilisant des algorithmes d'optimisation combinatoire pour explorer de façon efficace l'espace des variables, et l'autre définissant un modèle de régression regroupant ensemble les variables ayant un effet similaire.

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Laraufie, Romain. « Simulations avancées de turbulence pariétale à haut nombre de Reynolds sur des géométries curvilignes par une approche hybride RANS/LES ». Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00831614.

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La capacité de simuler la dynamique de la couche limite turbulente représente aujourd'hui un enjeu important pour la prévision de l'aérodynamique instationnaire et de l'aéroacoustique des aéronefs et des véhicules terrestres. Aussi, les travaux présentés dans ce manuscrit proposent une méthode originale de simulation de la dynamique des écoulements turbulents pariétaux, à haut nombre de Reynolds, sur des géométries curvilignes. L'approche ZDES, dans son mode " Wall Modelled Large Eddy Simulation ", est ici retenue. Dans un premier temps, une méthode de réactivation turbulente, par combinaison de l'injection de turbulence synthétique et de l'application de termes de forçage, est développée afin de permettre une résolution WMLES locale des régions d'intérêt au sein d'une simulation majoritairement RANS. Puis l'étude des interactions entre la physique et la méthode de résolution numérique (ZDES), sur le cas d'une couche limite turbulente sans gradient de pression en développement spatial jusqu'à Re13 000, a conduit à une généralisation des conditions d'emploi du mode WMLES de la ZDES. Des post-traitements instationnaires avancés ont permis de démontrer la capacité de la méthode à simuler la dynamique particulière de la zone externe à ces grands nombres de Reynolds. Enfin, les différentes méthodes développées au cours de cette étude ont été appliquées à la simulation d'une manche à air coudée de section rectangulaire. Cette nouvelle méthode a permis de simuler avec succès la dynamique multi-échelles de cet écoulement et des distorsions dynamiques associées, pour un coût environ 50 fois inférieur à celui d'une approche LES classique

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Distel, Christopher A. « Effects of an Insecticide on Competition in Anurans : Could Pesticide-Induced Competitive Exclusion be a Mechanism for Amphibian Declines ? » Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1280363910.

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Ramirez, Villalba Leidy catherine. « Towards an efficient modeling of Fluid-Structure Interaction ». Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0029.

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Les applications industrielles FSI se caractérisent par des géométries et des matériaux complexes. Afin de prédire avec précision leur comportement, des coûts de calcul élevés sont associés, à la fois en temps et en ressources informatiques. Pour améliorer la qualité de la prédiction sans pénaliser le temps de calcul, et pour réduire le temps de calcul sans impacter la précision disponible aujourd'hui, deux axes principaux sont explorés dans ce travail. Le premier est l'étude d'un algorithme asynchrone qui pourrait permettre l'utilisation de modèles structurels complexes. Le second consiste à étudier la méthode des tranches en combinant l'utilisation d'un modèle RANS et d'un modèle FEM non linéaire. D'une part, l'étude de l'asynchronicité dans le domaine FSI a révélé différents aspect d'intérêt qui doivent être approfondis avant que l'approche puisse être utilisée industriellement. Cependant, un premier traitement des points mentionnés ci-dessus a montré des signe d'amélioration qui pourraient conduire à un algorithme prometteur, qui se situe naturellement entre l'algorithme explicite et l'algorithme implicite. D'autre part, il a été montré que la méthode des tranches développée dans ce travail conduit à une réduction significative du temps de calcul sans dégradation de la précision
FSI industrial applications are often described by complex geometries and materials. In order to accurately predict their behavior, high computational costs are associated, both in time and in computational resources. To improve the quality of the prediction without penalizing the computational time, and to reduce the computational time without impacting the accuracy that is available today, two main axes are explored in this work. The first one is the study of an asynchronous algorithm that could allow the use of complex structural models. The second axis consists of the study of the strip method while combining the use of a RANS model and a non-linear FEM model. On the one hand, the study of asynchronicity in the FSI domain revealed different aspects of interest that must be addressed before the approach can be used industrially. However, a first treatment of the limitations found showed signs of an improvement that could lead to a promising algorithm, one that naturally lies between the implicit external algorithm and the implicit internal algorithm. On the other hand, it was shown that the strip method developed in this work achieves a significant reduction in calculation time while maintaining excellent accuracy

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Chen, Zhangchi. « Differential invariants of parabolic surfaces and of CR hypersurfaces ; Directed harmonic currents near non-hyperbolic linearized singularities ; Hartogs’ type extension of holomorphic line bundles ; (Non-)invertible circulant matrices On differential invariants of parabolic surfaces A counterexample to Hartogs’ type extension of holomorphic line bundles Directed harmonic currents near non-hyperbolic linearized singularities Affine Homogeneous Surfaces with Hessian rank 2 and Algebras of Differential Invariants On nonsingularity of circulant matrices ». Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASM005.

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La thèse se compose de 6 articles. (1) Nous calculons les générateurs des SA₃(ℝ)-invariants pour les surfaces paraboliques. (2) Nous calculons les invariants rigides relatifs pour les hypersurfaces rigides 2-non-dégénérées de rang de Levi constant 1 dans ℂ³: V₀, I₀, Q₀ ayant 11, 52, 824 monômes au numérateur. (3) Nous organisons tous les modèles affinement homogènes non-dégénérés dans ℂ³ en branches inéquivalentes. (4) Pour un courant harmonique dirigé autour d'une singularité linéarisée non-hyperbolique qui ne charge pas les séparatrices triviales dont l'extension triviale à travers 0 est ddc-fermée, nous démontrons que le nombre de Lelong en 0 est : 4.1) strictement positif si λ>0 ; 4.2) nul si λ est rationnel et négatif ; 4.3) nul si λ est négatif et si T est invariant sous l'action d'un sous-groupe cofini du groupe de monodromie. (5) Nous construisons des fibrés holomorphes en droites en toute dimension n>=2 non-prolongeables au sens de Hartogs. (6) Nous montrons que les matrices circulantes ayant k entrées 1 et k+1 entrées 0 dans leur première rangée sont toujours non singulières lorsque 2k+1 est soit une puissance d'un nombre premier, soit un produit de deux nombres premiers distincts. Pour tout autre entier 2k+1, nous exhibons une matrice circulante singulière
The thesis consists of 6 papers. (1) We calculate the generators of SA₃(ℝ)-invariants for parabolic surfaces. (2) We calculate rigid relative invariants for rigid constant Levi-rank 1 and 2-non-degenerate hypersurfaces in ℂ³: V₀, I₀, Q₀ having 11, 52, 824 monomials in their numerators. (3) We organize all affinely homogeneous nondegenerate surfaces in ℂ³ in inequivalent branches. (4) For a directed harmonic current near a non-hyperbolic linearized singularity which does not give mass to any of the trivial separatrices and whose trivial extension across 0 is ddc-closed, we show that the Lelong number at 0 is: 4.1) strictly positive if the eigenvalue λ>0; 4.2) zero if λ is a negative rational number; 4.3) zero if λ<0 and if T is invariant under the action of some cofinite subgroup of the monodromy group. (5) We construct non-extendable, in the sense of Hartogs, holomorphic line bundles in any dimension n>=2. (6) We show that circulant matrices having k ones and k+1 zeros in the first row are always nonsingular when 2k+1 is either a power of a prime, or a product of two distinct primes. For any other integer 2k+1 we exhibit a singular circulant matrix

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Lebed, Victoria. « Objets tressés : une étude unificatrice de structures algébriques et une catégorification des tresses virtuelles ». Phd thesis, Université Paris-Diderot - Paris VII, 2012. http://tel.archives-ouvertes.fr/tel-00775857.

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Dans cette thèse on développe une théorie générale des objets tressés et on l'applique à une étude de structures algébriques et topologiques. La partie I contient une théorie homologique des espaces vectoriels tressés et modules tressés, basée sur le coproduit de battage quantique. La construction d'un tressage structurel qui caractérise diverses structures - auto-distributives (AD), associatives, de Leibniz - permet de généraliser et unifier des homologies familières. Les hyper-bords de Loday, ainsi que certaines opérations homologiques, apparaissent naturellement dans cette interprétation. On présente ensuite des concepts de système tressé et module multi-tressé. Appliquée aux bigèbres, bimodules, produits croisés et (bi)modules de Hopf et de Yetter-Drinfel'd, cette théorie donne leurs interprétations tressées, homologies et actions adjointes. La no- tion de produits tensoriels multi-tressés d'algèbres donne un cadre unificateur pour les doubles de Heisenberg et Drinfel'd, ainsi que les algèbres X de Cibils-Rosso et Y et Z de Panaite. La partie III est orientée vers la topologie. On propose une catégorification des groupes de tresses virtuelles en termes d'objets tressés dans une catégorie symétrique (CS). Cette approche de double tressage donne une source de représentations de V Bn et un traitement catégorique des racks virtuels de Manturov et de la représentation de Burau tordue. On définit ensuite des structures AD dans une CS arbitraire et on les munit d'un tressage. Les techniques tressées de la partie I amènent alors à une théorie homologique des structures AD catégoriques. Les algèbres associatives, de Leibniz et de Hopf rentrent dans ce cadre catégorique.

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MACCIONI, MAURO. « Tensor rank and eigenvectors ». Doctoral thesis, 2017. http://hdl.handle.net/2158/1077336.

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I investigate on the number t of real eigenvectors of a real symmetric tensor. In particular, given a homogeneous polynomial f of degree d in 3 variables, I prove that t is greater or equal than 2c+1, if d is odd, and t is greater or equal than max(3,2c+1), if d is even, where c is the number of ovals in the zero locus of f. About binary forms, I prove that t is greater or equal than the number of real roots of f. Moreover, the above inequalities are sharp for binary forms of any degree and for cubic and quartic ternary forms. Previously, I worked on the computation of the real ranks of real binary forms of degree four and five with assigned complex rank.

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28

Gouaya, Guy Mathias. « Algebraic and multilinear-algebraic techniques for fast matrix multiplication ». Diss., 2015. http://hdl.handle.net/10500/20180.

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This dissertation reviews the theory of fast matrix multiplication from a multilinear-algebraic point of view, as well as recent fast matrix multiplication algorithms based on discrete Fourier transforms over nite groups. To this end, the algebraic approach is described in terms of group algebras over groups satisfying the triple product Property, and the construction of such groups via uniquely solvable puzzles. The higher order singular value decomposition is an important decomposition of tensors that retains some of the properties of the singular value decomposition of matrices. However, we have proven a novel negative result which demonstrates that the higher order singular value decomposition yields a matrix multiplication algorithm that is no better than the standard algorithm.
Mathematical Sciences
M. Sc. (Applied Mathematics)

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Tung, Shiu-Feng, et 董須豐. « Purification and characterization of a ribonuclease-inhibitor complex from Rana catesbeiana oocytes ». Thesis, 1993. http://ndltd.ncl.edu.tw/handle/90206202664157968074.

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碩士
國立清華大學
輻射生物研究所
81
There are two forms of RC-RNase, free form and latent form, found in the oocyte of bullfrog (Rana catesbeiana). The latent form of RC-RNase is complexed with an RNase inhibitor (RCI). This RC-RNase-RCI complex was purified to homogeneity by a combination of phosphocellulose chromatography, ammonium sulfate fractionation, DEAE-cellulose chromatography and affinity chromatography. The molecular weight of RCI, estimated by 6% SDS-PAGE,is about 110,000 Daltons. The RCI could be irreversibly activated by heating to 60 C for 20 minutes, 3 M of urea oruM of p-hydroxymercuribenzoate(p-HMB). Further purification of RCI from RC-RNase-RCI complex was tried and discussed.

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30

Ribeiro, Duarte Chambel. « Coherent presentation for the hypoplactic monoid of rank n ». Master's thesis, 2017. http://hdl.handle.net/10362/23281.

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In this thesis, we construct a coherent presentation for the hypoplactic monoid of rank n and characterize the confluence diagrams associated with it, then we use the theory of quasi-Kashiwara operators and quasi-crystal graphs to prove that all confluence diagrams can be obtained from those diagrams whose vertices are highest-weight words. To do so, we first give a complete rewriting system for the hypoplactic monoid of rank n, then, using an extension of the Knuth–Bendix completion procedure called the homotopical completion procedure, we compute the previously mentioned coherent presentation, which, from a viewpoint of Monoidal Category Theory, gives us a family of generators of the relations amongst the relations. These coherent presentations are used for representations of monoids and are particularly useful to describe actions of monoids on categories. The theoretical background is given without proof, since the main purpose of this thesis is to present new results.

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31

Wang, Hui-Min, et 汪惠敏. « Constructing Endophenotypes of Complex Diseases Using Non-Negative Matrix Factorization and Adjusted Rand Index ». Thesis, 2012. http://ndltd.ncl.edu.tw/handle/nnjs4h.

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博士
國立陽明大學
公共衛生研究所
101
Complex diseases are typically caused by combinations of molecular disturbances that might vary strongly in different patients. Endophenotypes offer a simplified approach to this problem by reducing genetic heterogeneity. To construct endophenotype of complex disease, a supervised learning method, support vector machine (SVM), was firstly tried to apply. However, there were several difficulties. For example, high-dimension data structure and missing value of covariates in control dataset. These problems were reduced the accuracy of prediction in SVM. Since molecular dissimilarities often exist between patients with indistinguishable disease symptoms, and these unique molecular features may underlie pathogenic heterogeneity. In order to detect molecular dissimilarities between patients and to reduce the complexity of high-dimension data, we have explored an endophenotype-identification analytic procedure that combines non-negative matrix factorization (NMF) and adjusted rand index (ARI). To evaluate this procedure, we compared it with a common used method principal component analysis with k-means clustering (PCA-K). A simulation study with gene expression datasets that added genotype informative was conducted to examine the performance between our procedure and PCA-K. Our results showed that NMF was superior to PCA-K. Additionally, we performed our proposed procedure with a publicly available dataset of Alzheimer’s disease (LOAD). NMF distilled information associated with 1,116 transcripts into three metagenes and three molecular subtypes among patients with LOAD ( ): MS1 ( ), MS2 ( ), and MS3 ( ). ARI was then used to determine the most representative transcripts for each metagene. As results, 123, 89, and 71 metagene-specific transcripts were identified for MS1, MS2, and MS3, respectively. These metagene-specific transcripts could be treated as endophenotypes. Our findings revealed that MS1 might have a specific biological characteristic relative to APOE gene comparing to other molecular subtypes and MS2 might be a normal-like subtype. Our proposed procedure provided an alternative approach to investigate the pathogenic mechanism of disease to better understand the relationship between phenotype and genetic information.

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Flotho, Annette. « Characterizing the RanGAP1-RanBP2 complex in mitosis ». Doctoral thesis, 2008. http://hdl.handle.net/11858/00-1735-0000-0006-AD39-C.

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Szydlik, Stephen. « Milnor fiber complexes for rank 2 Shephard groups and a note on the Poincarʹe polynomial of an arrangement ». 1997. http://catalog.hathitrust.org/api/volumes/oclc/37623346.html.

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Nourse, Jonathan Alan. « Geological Evolution of Two Crustal Scale Shear Zones : Part I : The Rand Thrust Complex, Northwestern Mojave Desert, California. Part II : The Magdalena Metamorphic Core Complex, North Central Sonora, Mexico ». Thesis, 1989. https://thesis.library.caltech.edu/8067/2/Nourse_ja_1989.pdf.

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The geology and structure of two crustal scale shear zones were studied to understand the partitioning of strain within intracontinental orogenic belts. Movement histories and regional tectonic implications are deduced from observational data. The two widely separated study areas bear the imprint of intense Late Mesozoic through Middle Cenozoic tectonic activity. A regional transition from Late Cretaceous-Early Tertiary plutonism, metamorphism, and shortening strain to Middle Tertiary extension and magmatism is preserved in each area, with contrasting environments and mechanisms. Compressional phases of this tectonic history are better displayed in the Rand Mountains, whereas younger extensional structures dominate rock fabrics in the Magdalena area.

In the northwestern Mojave desert, the Rand Thrust Complex reveals a stack of four distinctive tectonic plates offset along the Garlock Fault. The lowermost plate, Rand Schist, is composed of greenschist facies metagraywacke, metachert, and metabasalt. Rand Schist is structurally overlain by Johannesburg Gneiss (= garnet-amphibolite grade orthogneisses, marbles and quartzites), which in turn is overlain by a Late Cretaceous hornblende-biotite granodiorite. Biotite granite forms the fourth and highest plate. Initial assembly of the tectonic stack involved a Late Cretaceous? south or southwest vergent overthrusting event in which Johannesburg Gneiss was imbricated and attenuated between Rand Schist and hornblende-biotite granodiorite. Thrusting postdated metamorphism and deformation of the lower two plates in separate environments. A post-kinematic stock, the Late Cretaceous Randsburg Granodiorite, intrudes deep levels of the complex and contains xenoliths of both Rand Schist and mylonitized Johannesburg? gneiss. Minimum shortening implied by the map patterns is 20 kilometers.

Some low angle faults of the Rand Thrust Complex formed or were reactivated between Late Cretaceous and Early Miocene time. South-southwest directed mylonites derived from Johannesburg Gneiss are commonly overprinted by less penetrative north-northeast vergent structures. Available kinematic information at shallower structural levels indicates that late disturbance(s) culminated in northward transport of the uppermost plate. Persistence of brittle fabrics along certain structural horizons suggests a possible association of late movement(s) with regionally known detachment faults. The four plates were juxtaposed and significant intraplate movements had ceased prior to Early Miocene emplacement of rhyolite porphyry dikes.

In the Magdalena region of north central Sonora, components of a pre-Middle Cretaceous stratigraphy are used as strain markers in tracking the evolution of a long lived orogenic belt. Important elements of the tectonic history include: (1) Compression during the Late Cretaceous and Early Tertiary, accompanied by plutonism, metamorphism, and ductile strain at depth, and thrust driven? syntectonic sedimentation at the surface. (2) Middle Tertiary transition to crustal extension, initially recorded by intrusion of leucogranites, inflation of the previously shortened middle and upper crustal section, and surface volcanism. (3) Gravity induced development of a normal sense ductile shear zone at mid crustal levels, with eventual detachment and southwestward displacement of the upper crustal stratigraphy by Early Miocene time.

Elucidation of the metamorphic core complex evolution just described was facilitated by fortuitous preservation of a unique assemblage of rocks and structures. The "type" stratigraphy utilized for regional correlation and strain analysis includes a Jurassic volcanic arc assemblage overlain by an Upper Jurassic-Lower Cretaceous quartz pebble conglomerate, in turn overlain by marine strata with fossiliferous Aptian-Albian limestones. The Jurassic strata, comprised of (a) rhyolite porphyries interstratified with quartz arenites, (b) rhyolite cobble conglomerate, and (c) intrusive granite porphyries, are known to rest on Precambrian basement north and east of the study area. The quartz pebble conglomerate is correlated with the Glance Conglomerate of southeastern Arizona and northeastern Sonora. The marine sequence represents part of an isolated arm? of the Bisbee Basin.

Crosscutting structural relationships between the pre-Middle Cretaceous supracrustal section, younger plutons, and deformational fabrics allow the tectonic sequence to be determined. Earliest phases of a Late Cretaceous-Early Tertiary orogeny are marked by emplacement of the 78 ± 3 Ma Guacomea Granodiorite (U/Pb zircon, Anderson et al., 1980) as a sill into deep levels of the layered Jurassic series. Subsequent regional metamorphism and ductile strain is recorded by a penetrative schistosity and lineation, and east-west trending folds. These fabrics are intruded by post-kinematic Early Tertiary? two mica granites. At shallower crustal levels, the orogeny is represented by north directed thrust faulting, formation of a large intermontane basin, and development of a pronounced unconformity. A second important phase of ductile strain followed Middle Tertiary? emplacement of leucogranites as sills and northwest trending dikes into intermediate levels of the deformed section (surficial volcanism was also active during this transitional period to regional extension). Gravitational instabilities resulting from crustal swelling via intrusion and thermal expansion led to development of a ductile shear zone within the stratigraphic horizon occupied by a laterally extensive leucogranite sill. With continued extension, upper crustal brittle normal faults (detachment faults) enhanced the uplift and tectonic denudation of this mylonite zone, ultimately resulting in southwestward displacement of the upper crustal stratigraphy.

Strains associated with the two ductile deformation events have been successfully partitioned through a multifaceted analysis. R_f/Ø measurements on various markers from the "type" stratigraphy allow a gradient representing cumulative strain since Middle Cretaceous time to be determined. From this gradient, noncoaxial strains accrued since emplacement of the leucogranites may be removed. Irrotational components of the postleucogranite strain are measured from quartz grain shapes in deformed granites; rotational components (shear strains) are determined from S-C fabrics and from restoration of rotated dike and vein networks. Structural observations and strain data are compatable with a deformation path of: (1) coaxial strain (pure shear?), followed by (2) injection of leucogranites as dikes (perpendicular to the minimum principle stress) and sills (parallel to the minimum principle stress), then (3) southwest directed simple shear. Modeling the late strain gradient as a simple shear zone permits a minimum displacement of 10 kilometers on the Magdalena mylonite zone/detachment fault system. Removal of the Middle Tertiary noncoaxial strains yields a residual (or pre-existing) strain gradient representative of the Late Cretaceous-Early Tertiary deformation. Several partially destrained cross sections, restored to the time of leucogranite emplacement, illustrate the idea that the upper plate of the core complex bas been detached from a region of significant topographic relief. 50% to 100% bulk extension across a 50 kilometer wide corridor is demonstrated.

Late Cenozoic tectonics of the Magdalena region are dominated by Basin and Range style faulting. Northeast and north-northwest trending high angle normal faults have interacted to extend the crust in an east-west direction. Net extension for this period is minor (10% to 15%) in comparison to the Middle Tertiary detachment related extensional episode.

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Nsimba, Elysee Bakatula. « Cyanide and cyanide complexes in the goldmine polluted land in the East and Central Rand Goldfields, South Africa ». Thesis, 2009. http://hdl.handle.net/10539/7052.

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The use of cyanide in gold extraction is of concern when it is not properly managed from the extraction process to the management of wastes. The distribution and fate of cyanide in the environment upon release from the tailings dumps depends on its physical-chemical speciation. This study presents results of distribution, speciation and fate of cyanide in selected compartments, namely: tailings, sediments and water systems in gold mine polluted land. Sampling of tailings in a facility that is being rehabilitated was done in 2006 and 2007 to assess the impact of AMD on cyanide release over that period. Deposition of materials in the tailings dams stopped in 2004. The results revealed that the pH of the tailings decreased between 2006 and 2007. Elevated concentrations of CNfree, SCN- and CNO- were observed for 2007 compared to 2006. Most cyanide species had degraded as a result, primarily, of decrease in pH due to generation of AMD, also the oxidation of CNfree and the reaction with active sulphur species such as S2O3. The decrease of cyanide total (CNT) with time is a consequence of natural attenuation of cyanides in tailings which may be attributed to physicalchemical and microbiological mechanisms. Cyanide and its metal complexes were found to be unstable following generation of AMD in the dump over a period of one year. The dissociation of metal-cyanide complexes when the pH drops, releases CNfree which is either volatilised as HCN(g) or transported in solution with the contamination plume or converted to SCN- ,CNO- and NH4 +. However, in most of cases high concentrations of metal-cyanide complexes were found even at low pH values of the tailings suggesting that these complexes are very stable. This was substantiated by the geochemical modelling which predicted the predominance of iron-cyanide complexes in tailings at low pH. iii Cyanide released from cyanide complexes flows into the central pond of the tailings facility and partly leaches into the groundwater. Salt crusts were observed along the capillary fringe of the central pond as well as around other water bodies considered in the study. These crusts were found to contain elevated concentrations of heavy metals (e.g. 12940 mg kg-1 Fe and 186.1 mg kg-1 Co) and cyanide (e.g. 118.4 mg kg-1 CNT, 14.36 mg kg-1 CNWAD and 100.2 mg kg-1 CNSAD). This obviously has implications of secondary pollution as these crusts tend to be very soluble in water thus leading to the release of heavy metals and cyanide into water systems during rainfall. Characterization of cyanide was also done in drainage water from an active slimes dam where deposition from a reprocessing plant takes place. The slimes dam had drainage pipes and a solution trench around it that drained away excess water. Low concentration of CNT was obtained in pipe water from the pipe with low pH values (2 - 4) whilst this concentration was high in water from the trench with high pH values (5 -7). Copper and iron complexes were the most abundant. High concentrations of SCN- and CNO- were obtained as result of conversion of CNfree as explained previously. Salt crusts collected around the dam presented low pH (3) and high conductivity, the evidence of high metals content. High concentrations (198.4 mg kg-1) of CNT were obtained in the crusts with predominance of CNSAD (Fe and Co). The bluish-green colour of the crusts and the elevated concentrations of CNSAD as well as those for iron could suggest the presence of Prussian blue. Analysis of the wetland sediments showed the transport of cyanide from the tailings dumps to the wetland through the streams. An enrichment of cyanide was observed in the sediment with the enrichment factor of 3 for CNT with predominance of strong complexes (Fe and Co). The sediment is rich in organic matter and cyanide is known to bind strongly with organic matter. Although other possible sources (e.g. bacterial or microbial sources) could have contributed to the enrichment of cyanide in sediment, this was not investigated. Cyanide can be transported from the tailings dams to natural streams and other surface water bodies through groundwater. A natural stream within a reprocessing area was considered as a water system and cyanide in it was characterised. Three clusters were observed: water collected upstream with high pH, water from downstream with low pH (4) and the groundwater with low pH (3). Low concentrations of CNfree were obtained downstream. This could be due by the lost of CNfree by volatilization due acidic pH conditions. CNT was found to be lower downstream than upstream with the predominance of CNWAD. CNT concentrations were high at the seepage point, where the groundwater discharges to the surface. These concentrations were similar to those obtained in the groundwater. Copper and iron complexes were dominant in the surface and groundwater and this was substantiated by modelling results as well. SCN- was not detected in surface water as it is highly soluble in water and then leaches in the groundwater. The concentrations of CNO- were the same up and downstream. The results obtained from the study revealed that concentration of CNfree in most water bodies exceeded stipulated limits by bodies such as WHO, USEPA and UE. For instance, concentrations of up to 0.304 mg l-1 of CNfree were obtained in some instances to compare with limits of 0.07 mg l-1 by WHO, 0.02 mg l-1 by DWAF/South Africa. Additional studies should be done to find out the impact of organic matter (e.g. humic and fulvic acids) on the fate of cyanide. Various natural attenuation mechanisms of cyanide in tailings dams should be investigated. An assessment of the phytoremediation program vis-à-vis cyanide cyclisation is recommended and a monitoring of groundwater (borehole water) quality is required.

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Chien-chang, Tseng, et 曾建璋. « Part I. Crystal Structure of Cytotoxic RC-RNase3 from Rana catesbeiana in Complex with Heparin Part II. Crystallization and Preliminary X-ray Diffraction Analysis of Muscarinic Toxin-Like Proteins,BM14 and BM8 from Bungarus multicinctus ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/00852193855937445814.

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碩士
國立清華大學
生命科學系
92
Crystal Structure of Cytotoxic RC-RNase3 from Rana catesbeiana in Complex with Heparin Abstract The Rana catesbeiana (bullfrog) ribonucleases, which belong to the RNase A superfamily, exert cytotoxicity and lectin activity. RC-RNase3 has a unique base preference for pyrimidine-guanine rather than pyrimidine-adenine in RNase A. The crystal structure of RC-RNase3 in complex with heparin disaccharide was determined to resolution of 1.6Å. Heparin is one type of glycosaminoglycan locating primarily on the surface of cells or in the extra-cellular matrix. The overall structure of RC-RNase3-heparin complex consists of seven β-strands and three α-helices that present a bowl shape. Heparin was found locating between sheet 1 (β1, β2, β4, and β5) and sheet 2 (β3, β6, and β7). One of the sulfate groups in heparin takes place in a very close position to the free sulfate in the retro binding RC-RNase6 and d(CpG) complex. More interestingly, two sulfate groups in heparin are close to the phosphate groups of d(ApCpGpA) in the catalytic binding RC-RNase and d(ApCpGpA) complex. Our results indicate a new binding mode where heparin sharing approximately the same binding site to the catalytic and retro binding modes. Crystallization and Preliminary X-ray Diffraction Analysis of Muscarinic Toxin-Like Protein, BM14 and BM8 from Bungarus multicinctus Abstract Two novel proteins BM14 and BM8 were isolated from Bungarus multicinctus (Taiwan banded krait) venom. BM14 and BM8 are sequence identical except Lys37-Lys38 in BM14 and Glu37-Ala38 in BM8. In contrast to BM8, BM14 exhibited an activity on binding to the M2 muscarinic acetlycholine (mAchR) receptor subtype, indicating Lys37 and Lys38 of BM14 play the crucial roles on binding to M2 mAchR. Although BM14 and BM8 shared a 20-38% sequence identity with snake venom cardiotoxins, they did not show the cytotoxicity. Eight out of ten Cys residues in BM14 and BM8 are located at the conserved positions as those in neurotoxin, cardiotoxin and muscarinic toxin protein sequences, so called the three-finger protein. BM14 and BM8 crystals were grown by the hanging drop vapor diffusion method. The crystals of BM14 diffract to 3.0Å and belong to the tetragonal space group I422 with unit-cell parameters a=81.68Å, b=81.68Å, c=207.30Å, and α=β=γ=90°. The crystals of BM8 diffract to 3.8 Å and belong to the hexagonal space group with unit-cell parameters a=55.37Å, b=55.37Å, c=338.0Å, α=β=90°, and γ=120°.

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Shakibaei, M., C. Buhrmann et A. Mobasheri. « Resveratrol-mediated SIRT-1 interactions with p300 modulate receptor activator of NF-kappaB ligand (RANKL) activation of NF-kappaB signaling and inhibit osteoclastogenesis in bone-derived cells ». 2011. http://hdl.handle.net/10454/6182.

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Resveratrol is a polyphenolic phytoestrogen that has been shown to exhibit potent anti-oxidant, anti-inflammatory, and anti-catabolic properties. Increased osteoclastic and decreased osteoblastic activities result in bone resorption and loss of bone mass. These changes have been implicated in pathological processes in rheumatoid arthritis and osteoporosis. Receptor activator of NF-kappaB ligand (RANKL), a member of the TNF superfamily, is a major mediator of bone loss. In this study, we investigated the effects of resveratrol on RANKL during bone morphogenesis in high density bone cultures in vitro. Untreated bone-derived cell cultures produced well organized bone-like structures with a bone-specific matrix. Treatment with RANKL induced formation of tartrate-resistant acid phosphatase-positive multinucleated cells that exhibited morphological features of osteoclasts. RANKL induced NF-kappaB activation, whereas pretreatment with resveratrol completely inhibited this activation and suppressed the activation of IkappaBalpha kinase and IkappaBalpha phosphorylation and degradation. RANKL up-regulated p300 (a histone acetyltransferase) expression, which, in turn, promoted acetylation of NF-kappaB. Resveratrol inhibited RANKL-induced acetylation and nuclear translocation of NF-kappaB in a time- and concentration-dependent manner. In addition, activation of Sirt-1 (a histone deacetylase) by resveratrol induced Sirt-1-p300 association in bone-derived and preosteoblastic cells, leading to deacetylation of RANKL-induced NF-kappaB, inhibition of NF-kappaB transcriptional activation, and osteoclastogenesis. Co-treatment with resveratrol activated the bone transcription factors Cbfa-1 and Sirt-1 and induced the formation of Sirt-1-Cbfa-1 complexes. Overall, these results demonstrate that resveratrol-activated Sirt-1 plays pivotal roles in regulating the balance between the osteoclastic versus osteoblastic activity result in bone formation in vitro thereby highlighting its therapeutic potential for treating osteoporosis and rheumatoid arthritis-related bone loss.

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