Ces dernières années, l'importance cruciale des métriques en apprentissage automatique a mené à un intérêt grandissant pour l'optimisation de distances et de similarités en utilisant l'information contenue dans des données d'apprentissage pour les rendre adaptées au problème traité. Ce domaine de recherche est souvent appelé apprentissage de métriques. En général, les méthodes existantes optimisent les paramètres d'une métrique devant respecter des contraintes locales sur les données d'apprentissage. Les métriques ainsi apprises sont généralement utilisées dans des algorithmes de plus proches voisins ou de clustering.Concernant les données numériques, beaucoup de travaux ont porté sur l'apprentissage de distance de Mahalanobis, paramétrisée par une matrice positive semi-définie. Les méthodes récentes sont capables de traiter des jeux de données de grande taille.Moins de travaux ont été dédiés à l'apprentissage de métriques pour les données structurées (comme les chaînes ou les arbres), car cela implique souvent des procédures plus complexes. La plupart des travaux portent sur l'optimisation d'une notion de distance d'édition, qui mesure (en termes de nombre d'opérations) le coût de transformer un objet en un autre.Au regard de l'état de l'art, nous avons identifié deux limites importantes des approches actuelles. Premièrement, elles permettent d'améliorer la performance d'algorithmes locaux comme les k plus proches voisins, mais l'apprentissage de métriques pour des algorithmes globaux (comme les classifieurs linéaires) n'a pour l'instant pas été beaucoup étudié. Le deuxième point, sans doute le plus important, est que la question de la capacité de généralisation des méthodes d'apprentissage de métriques a été largement ignorée.Dans cette thèse, nous proposons des contributions théoriques et algorithmiques qui répondent à ces limites. Notre première contribution est la construction d'un nouveau noyau construit à partir de probabilités d'édition apprises. A l'inverse d'autres noyaux entre chaînes, sa validité est garantie et il ne comporte aucun paramètre. Notre deuxième contribution est une nouvelle approche d'apprentissage de similarités d'édition pour les chaînes et les arbres inspirée par la théorie des (epsilon,gamma,tau)-bonnes fonctions de similarité et formulée comme un problème d'optimisation convexe. En utilisant la notion de stabilité uniforme, nous établissons des garanties théoriques pour la similarité apprise qui donne une borne sur l'erreur en généralisation d'un classifieur linéaire construit à partir de cette similarité. Dans notre troisième contribution, nous étendons ces principes à l'apprentissage de métriques pour les données numériques en proposant une méthode d'apprentissage de similarité bilinéaire qui optimise efficacement l'(epsilon,gamma,tau)-goodness. La similarité est apprise sous contraintes globales, plus appropriées à la classification linéaire. Nous dérivons des garanties théoriques pour notre approche, qui donnent de meilleurs bornes en généralisation pour le classifieur que dans le cas des données structurées. Notre dernière contribution est un cadre théorique permettant d'établir des bornes en généralisation pour de nombreuses méthodes existantes d'apprentissage de métriques. Ce cadre est basé sur la notion de robustesse algorithmique et permet la dérivation de bornes pour des fonctions de perte et des régulariseurs variés / In recent years, the crucial importance of metrics in machine learningalgorithms has led to an increasing interest in optimizing distanceand similarity functions using knowledge from training data to make them suitable for the problem at hand.This area of research is known as metric learning. Existing methods typically aim at optimizing the parameters of a given metric with respect to some local constraints over the training sample. The learned metrics are generally used in nearest-neighbor and clustering algorithms.When data consist of feature vectors, a large body of work has focused on learning a Mahalanobis distance, which is parameterized by a positive semi-definite matrix. Recent methods offer good scalability to large datasets.Less work has been devoted to metric learning from structured objects (such as strings or trees), because it often involves complex procedures. Most of the work has focused on optimizing a notion of edit distance, which measures (in terms of number of operations) the cost of turning an object into another.We identify two important limitations of current supervised metric learning approaches. First, they allow to improve the performance of local algorithms such as k-nearest neighbors, but metric learning for global algorithms (such as linear classifiers) has not really been studied so far. Second, and perhaps more importantly, the question of the generalization ability of metric learning methods has been largely ignored.In this thesis, we propose theoretical and algorithmic contributions that address these limitations. Our first contribution is the derivation of a new kernel function built from learned edit probabilities. Unlike other string kernels, it is guaranteed to be valid and parameter-free. Our second contribution is a novel framework for learning string and tree edit similarities inspired by the recent theory of (epsilon,gamma,tau)-good similarity functions and formulated as a convex optimization problem. Using uniform stability arguments, we establish theoretical guarantees for the learned similarity that give a bound on the generalization error of a linear classifier built from that similarity. In our third contribution, we extend the same ideas to metric learning from feature vectors by proposing a bilinear similarity learning method that efficiently optimizes the (epsilon,gamma,tau)-goodness. The similarity is learned based on global constraints that are more appropriate to linear classification. Generalization guarantees are derived for our approach, highlighting that our method minimizes a tighter bound on the generalization error of the classifier. Our last contribution is a framework for establishing generalization bounds for a large class of existing metric learning algorithms. It is based on a simple adaptation of the notion of algorithmic robustness and allows the derivation of bounds for various loss functions and regularizers.

Cette thèse concerne les codes utilisés pour les télécommunications sans-fil multi-antennes. Les résultats portent notamment sur des constructions explicites ainsi que sur des bornes numériques et théoriques pour les cardinaux de ces codes. Le premier chapitre introduit brièvement les différents contextes multi-antennes et les modélisations qui leur sont associées. Les chapitres 2,3 et 4 traitent respectivement des codes dans les espaces grassmanniens, des codes dans les matrices unitaires et des codes dans les algèbres à division. / This thesis deals with codes used for multi-antennas wireless telecommunications. The results concern explicit constructions and bounds on the cardinalities of such codes (analytical and numerical bounds) . The first chapter introduce various modelisations of the multi-antennas wireless system and the related mathematical problems. Chapters 2,3,4 deal respectively with codes in Grassmannian spaces, code in unitary matrices and code in division algebras.

As cadeias estocásticas de memória ilimitada são uma generalização natural das cadeias de Markov, no caso em que as probabilidades de transição podem depender de todo o passado da cadeia. Estas cadeias, introduzidas, independentemente, por Onicescu e Mihoc em 1935 e Doeblin e Fortet em 1937, vêm recebendo uma atenção crescente na literatura probabilística, não só por serem uma classe mais rica que a classe das cadeias de Markov, como por suas capacidades práticas de modelagem de dados científicos em diversas áreas, indo da biologia à linguística. Neste trabalho, as utilizamos para modelar a interação entre sequências de disparos neuronais. Nosso objetivo principal é desenvolver novos resultados matemáticos acerca das cadeias de memória ilimitada. Inicialmente, estudamos as condições que garantem a existência e a unicidade de cadeias estacionárias compatíveis com uma família de probabilidades de transição descontínua. Em seguida, tratamos do entendimento da fenomenologia dos trens de disparos neuronais e usamos da informação dirigida para modelar a informação que flui de uma sequência de disparos a outra. Nesta ocasião, fixamos limites da concentração para estimação da informação dirigida. / Stochastic chains with unbounded memory are a natural generalization of Markov chains, in the sense that the transition probabilities may depend on the whole past. These process, introduced independently by Onicescu and Mihoc in 1935 and Doeblin and Fortet in 1937, have been receiving increasing attention in the probabilistic literature, because they form a class richer than the Markov chains and have practical capabilities modelling of scientific data in several areas, from biology to linguistics. In this work, we use them to model interactions between spike trains. Our main goal is to develop new mathematical results about stochastic chains with unbounded memory. First, we study conditions that guarantee the existence and uniqueness of stationary chains compatible with a discontinuous family of transition probabilities. Then, we address the understanding of the phenomenology of spike trains and we propose to use directed information to quantify the information flow from one neuron to another. In this occasion, we fix concentration bounds for directed information estimation.

No description available.

A Constituição Federal de 1988 inseriu no ordenamento jurídico uma série de direitos e garantias fundamentais. Dentre eles, pode-se citar a divisão de poderes, a qual distribuiu no texto constitucional o papel de cada ente estatal, sobretudo, para o presente estudo, a função relativa ao Judiciário. Nesse esteio, pode-se afirmar que tanto as normas promulgadas no período pós 1988, como as que foram recebidas pelo novo ordenamento, passaram a ser analisadas sob o espectro do prisma principiológico. As normas procedimentais e processuais coordenam os trilhos da aplicação do Direito ao caso concreto e a formação do Direito para o caso abstrato. No entanto, há que se mitigar toda aplicabilidade ordinária pelo tempero dos princípios. Essa pesquisa terá como guia a colisão entre os princípios processuais da efetividade e da instrumentalidade em face do devido processo legal. Tem-se por premissa que o percurso do devido processo deve servir como ferramenta para a busca pela decisão final de mérito e consequente pacificação social. Caso contrário, em nada serviria todo o aparato do judiciário disponibilizado para a população. Desse modo, o presente estudo propõe uma análise sobre a atuação do Estado-Juiz no que tange ao ativismo processual. Diante do objetivo maior, qual seja a necessidade de efetivação dos direitos fundamentais e sociais, o fenômeno do ativismo judicial às vezes esquecido, às vezes exacerbado, se mostra como ferramenta necessária no contexto destacado. / The Federal Constitutional of 1988 introduces at the legal system a series of fundamental rights and guarantees. Among them, its significant the division of powers, which distributed in the Constitution the role of each state entity, above all, for this study, the judiciary function. Thus, it can be said that both the rules promulgated in the period after 1988 as those received by the new system, have been analyzed through the principles spectrum prism. The procedural rules coordinate the application of law to the cases and the creation of law for abstract case. However, it is necessary to mitigate any regular applicability with the principles orientation. This research tries are the collision between the procedural principles of effectiveness and instrumentality in the face of due process of law. As premised the route of due process should serve as a tool to the final decision and consequent social peace. Otherwise, it would be unnecessary the entire legal apparatus available to the public. Lastly, this study proposes an analysis about the performance of the Judge-State regarding the judicial activism. Looking to a larger goal, the need for enforcement of fundamental and social rights, the judicial activism phenomenon sometimes forgotten, sometimes exacerbated, shown itself as a necessary tool in the context highlighted.

Diese Arbeit befasst sich mit Untersuchung der Hölder Calmness, eines Stabilitätskonzeptes das man als Verallgemeinerung des Begriffs der Calmness erhält. Ausgehend von Charakterisierungen dieser Eigenschaft für Niveaumengen von Funktionen, werden, unter der Voraussetzung der Hölder Calmness, Prozeduren zur Bestimmung von Elementen dieser Mengen analysiert. Ebenso werden hinreichende Bedingungen für Hölder Calmness studiert. Da Hölder Calmness (nichtleerer) Lösungsmengen endlicher Ungleichungssysteme mittels (lokaler) Fehlerabschätzungen beschrieben werden kann, werden auch Erweiterungen der lokalen zu globalen Ergebnissen diskutiert. Als Anwendung betrachten wir speziell den Fall von Niveaumengen von Polynomen bzw. allgemeine Lösungsmengen polynomialer Gleichungen und Ungleichungen. Eine konkrete Frage, die wir beantworten wollen, ist die nach dem Zusammenhang zwischen dem größten Grad der beteiligten Polynome sowie dem Typ, d.h. dem auftretenden Exponenten, der Hölder Calmness des entsprechenden Systems. / This thesis is concerned with an analysis of Hölder calmness, a stability property derived from the concept of calmness. On the basis of its characterization for (sub)level sets, we will cogitate about procedures to determine points in such sets under a Hölder calmness assumption. Also sufficient conditions for Hölder calmness of (sub)level sets and of inequality systems will be given and examined. Further, since Hölder calmness of (nonempty) solution sets of finite inequality systems may be described in terms of (local) error bounds, we will as well amplify the local propositions to global ones. As an application we investigate the case of (sub)level sets of polynomials and of general solution sets of polynomial equations and inequalities. A concrete question we want to answer here is, in which way the maximal degree of the involved polynomials is connected to the exponent of Hölder calmness or of the error bound for the system in question.

Made available in DSpace on 2016-04-26T18:14:10Z (GMT). No. of bitstreams: 1 Rodrigo Fonseca Fernandes.pdf: 2505031 bytes, checksum: c4760dc36224d7da88111c1494a3e713 (MD5) Previous issue date: 2014-06-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research investigates the tensions between the linear logic of radio production and the creative possibilities and liberating the language of radio. From the analysis of programs geared to children, we intend to demonstrate that the radio is a binding environment through sound performances from the bodies. In this way, we try to answer the following problem: to which extent the sound games present in children's programs allow the freedom of creation and disassembly of logical narrative elements among children? The goal is to understand the sound performances of the programmes in Brazilian radio stations as possible gestures of disassembly of the linear characteristics of traditional radio. The research has as corpus the following programs: Rádio Maluca and Estação Brincadeira MECRJ, both from Rádio MEC-Rio de Janeiro; Para ouvir e aprender program, broadcasted on Radio Rural de Santarém/Pará; pilot project Loja do Tio Nico, developed by students of Universidade Municipal de São Caetano do Sul; didactic audio Projeto Faz de Conta, produced by Rádio Cultura and used in schools in the State of São Paulo in Brazil. The performances were observed live from the Auditorium of Rádio Nacional, where it is broadcast Rádio Maluca program, between 2011 and 2012. The theoretical framework is based on concept of game in Huizinga and Caillois, which operates in constructions of cultural environments present in Bystrina, Wulf, Gebauer and Baitello Junior. The playful radio operation is possible through performances with sounds that have been observed in Schafer, Schaefffer, Sperber, Arnheim, Deharme e Menezes, looking for the aesthetic elements and binding present in radio soundscapes. It was observed that the games aired by radio children's programs explore the creativity of the child from elements of visuality, rather than purely sound creation / Esta pesquisa investiga as tensões entre as lógicas lineares da produção radiofônica e as possibilidades criativas e libertadoras da linguagem do rádio. A partir da análise de programas voltados às crianças, pretende-se demonstrar que o rádio é ambiente de vinculação através de performances sonoras oriundas dos corpos. Desta forma, busca-se responder ao seguinte problema: em que medida os jogos sonoros presentes nos programas infantis permitem a liberdade de criação e desmontagem de elementos lógicos narrativos entre as crianças? O objetivo é compreender a partir dos programas existentes em emissoras de rádios brasileiras as performances sonoras como possíveis gestos de desmontagem das características lineares do rádio tradicional. A pesquisa tem como corpus os seguintes programas: Rádio Maluca e Estação Brincadeira, ambos da Rádio MEC/RJ; programa Para Ouvir e Aprender, veiculado na Rádio Rural de Santarém-PA; projeto-piloto A Loja do Tio Nico, desenvolvido pelos alunos da Universidade Municipal de São Caetano do Sul; áudio didático Projeto Faz de Conta, produzido pela Rádio Cultura e utilizado nas escolas do Estado de São Paulo. Foram observadas as performances sonoras ao vivo no auditório da Rádio Nacional, de onde é transmitido o programa Rádio Maluca, entre os anos de 2011 e 2012. É proposto como referencial teórico o conceito de jogo em Huizinga e Caillois, que opera nas construções de ambientes culturais presentes em Bystrina, Wulf, Gebauer e Baitello Junior. A operação do lúdico no rádio é possível através de performances com sonoridades que foram observadas a partir de Schafer, Schaefffer, Sperber, Arnheim, Deharme e Menezes, buscando os elementos estéticos e de vinculação presentes nas paisagens sonoras do rádio. Observou-se que os jogos veiculados pelos programas infantis de rádio exploram a criatividade da criança a partir de elementos da visualidade, em detrimento da criação puramente sonora

Made available in DSpace on 2016-04-26T20:19:28Z (GMT). No. of bitstreams: 1 Gabriel Magalhaes Borges Prata.pdf: 1161117 bytes, checksum: 097b88b9075813692863edbcfe55b97f (MD5) Previous issue date: 2010-10-14 / This scientific work has the scope to identify the criteria that permit the semantics content delimitation expended to the tax legal competence norms, and establish the condition which is legitimized by this activity. In order to fulfill that purpose the academic assignment was divided in six chapters. At the first one, several epistemological premises shall be stated with the intention to guide and direct the entire task herein. Language concepts, as well as reality and its correlation with the Law will be spotted; the foremost matter developed herein concerns to the methods used to verify the significance of the words, which in our technical sense starts by the criteria acknowledged like concepts of use conceived by Wittgenstein. The main issue here concerns the way crafted check the meanings of words, a process that, in our experience, occurs from the use criteria such as Wittgenstein designed and engineered by Bakhtin's dialogism, authors whose thoughts will be addressed in second chapter. In the third, revisit the traditional conception of what is interpreted by comparing it with the thought of Gadamer, see how this activity gets a new contours from the perspective of philosophical hermeneutics and as the reason ceases to be something to put off any prior understanding of the world. In the fourth chapter, we will bring to the field of legal interpretation the ideas previously developed in order to confront them with the current concepts in the classical doctrine on the subject. At the fifth, we will bring closer the conclusions founded at the first ones above mentioned, with the intent to demonstrate how the legal language is provided and molded by the common, technical and scientific language. We will demonstrate that the use which is made of those languages games reverberates and influences the construction of the concepts employed at the tax legal competence norms, given to the fact that herein we approximate the dialogism conceived by Bakhtin, admitting thus that legal-prescriptive texts are connected with all species texts. Finally, at the last chapter, we will analyze some casuistic questions discussed at our National Supreme Court (Last Court of Appeals), in order to exhibit how the criteria structured during this work shall be employed to delimitate the significance contents that represents a true bound to the tax activities performed by the government bodies / Este trabalho tem por finalidade última identificar critérios que permitam encontrar limites à atividade de construção do conteúdo semântico dos conceitos empregados nas normas de competência tributária, assim como estabelecer a condição pela qual tal atividade pode se legitimar. A fim de realizar tal empresa, o trabalho será divido em seis capítulos. No primeiro, serão firmadas algumas premissas epistemológicas, que orientarão toda a pesquisa aqui realizada. Verse- ão conceitos de linguagem, realidade e sua co-relação com o direito. A principal questão aqui trabalhada diz respeito à forma de verificação dos significados das palavras, processo esse que, em nosso sentir, se dá a partir dos critérios de uso tais como concebidos por Wittgenstein e do dialogismo engendrado por Bakhtin, autores cujos pensamentos serão abordados no segundo capítulo. No terceiro, revisitaremos a tradicional concepção do que seja interpretação confrontando-a com pensamento de Gadamer; veremos como essa atividade ganha nova coloração sob a perspectiva da hermenêutica filosófica e como a razão deixa de ser um algo posto para fora de todo entendimento prévio de mundo. No quarto capítulo, traremos ao campo da hermenêutica jurídica as ideias até então desenvolvidas, a fim de confrontá-las com os conceitos vigentes na doutrina clássica sobre o tema. No quinto capítulo, aproximamos as conclusões firmadas nos quatro primeiros a fim de mostrar como a linguagem jurídica é informada e conformada pelas linguagens ordinária, técnica e científica, com as quais estabelece um constante diálogo. Mostraremos que os usos que se fazem no seio de tais tipos de linguagem repercutem e influenciam a construção dos conceitos empregados nas normas de competência, eis que os textos jurídico-prescritivos não encerram em si significados absolutos; evidenciaremos, ainda sob a influência da noção do dialogismo, como a tradição entra no discurso interpretativo como sua condição de possibilidade, na medida em que o diálogo com ela travado é o que a tornará legítima. Por fim, no último e sexto capítulo, faremos uma análise casuística de algumas questões debatidas no Supremo Tribunal Federal, em ordem a demonstrar como os critérios estruturados ao longo do trabalho podem ser empregados para delimitação de conteúdos de significado das normas de competência tributária

This study examined the relationship between a set of macroeconomic variables and stock market development in Hong Kong and the Philippines for the periods of 1992Q4-2016Q3 and 2001Q4-2016Q4 respectively. In recent decades, the stock markets in Hong Kong and the Philippines have experienced remarkable growth. While the literature has produced diverse views on the relationship between each determinant and the stock market, there are no relevant studies on the determinants of stock market development on these two countries. Against this background, this study enriched the literature by investigating the macroeconomic determinants of stock market development in these two countries using the autoregressive distributed lag bounds testing approach. The empirical results of this study revealed a number of interesting findings. In the case of Hong Kong, the results showed that banking sector development and economic growth exerted positive impacts, whereas the inflation rate and exchange rate exerted negative impacts on stock market development both in the long and short run. In addition, the results showed that trade openness had a positive long-run impact, but a negative short-run impact on stock market development. Therefore, policymakers should pursue policies that foster banking sector development, enhance economic growth and maintain trade openness in order to foster the development of the stock market. In addition, monetary authority should strive to maintain a low level of inflation rate and the value of the domestic currency so as to further promote stock market development. In the case of the Philippines, the study found that trade openness had a negative impact on the development of the stock market in the long run, whereas banking sector development, and the exchange rate had positive impacts in the short run. Based on these findings, policymakers should consider policies that promote the use of equity financing in the production of main exports, enhance banking sector development, and maintain the stability of the domestic currency in order to promote the development of the stock market. / Economics / D. Phil. (Economics)

The task of choosing a preconditioner M to use when solving a linear system Ax=b with iterative methods is often tedious and most methods remain ad-hoc. This thesis presents a randomized algorithm to make this chore less painful through use of randomized algorithms for estimating traces. In particular, we show that the preconditioner stability || I - M-1A ||F, known to forecast preconditioner quality, can be computed in the time it takes to run a constant number of iterations of conjugate gradients through use of sketching methods. This is in spite of folklore which suggests the quantity is impractical to compute, and a proof we give that ensures the quantity could not possibly be approximated in a useful amount of time by a deterministic algorithm. Using our estimator, we provide a method which can provably select a quality preconditioner among n candidates using floating operations commensurate with running about n log(n) steps of the conjugate gradients algorithm. In the absence of such a preconditioner among the candidates, our method can advise the practitioner to use no preconditioner at all. The algorithm is extremely easy to implement and trivially parallelizable, and along the way we provide theoretical improvements to the literature on trace estimation. In empirical experiments, we show the selection method can be quite helpful. For example, it allows us to create to the best of our knowledge the first preconditioning method for kernel regression which never uses more iterations over the non-preconditioned analog in standard settings.