This study utilizes major-, trace- and rare earth elements, as well as radiogenic isotopes (Rb-Sr, Sm-Nd, Pb), in bulk sediment, extracted glass shards, and discrete ash layers, at Ocean Drilling Program Site 1149 (Izu-Bonin Arc), Deep Sea Drilling Project Site 52 (Mariana Arc), and Integrated Ocean Drilling Program Sites C0011 and C0012 (Nankai Trough) in order to characterize and quantify the abundance of dispersed ash, rather than discrete ash layers, in sediments from the Northwest Pacific Ocean. Combination of the geochemical methods with multivariate statistical techniques, such as Q-mode Factor Analysis and multiple linear regressions, allows for differentiation of unique chemistries of the dispersed ash, and the terrigenous components. Therefore, we can document sources that change through time and space. At Site 1149 the bulk sediment is a mixture of two dust and two dispersed ash sources. The two dust sources show contrasting accumulation patterns changing over at a tectonically and climactically active time in Earth's past (~22 Ma) and yield a more complete history of Asian aridity than has been previously considered. We interpret the source of the ashes as basalt from the Izu-Bonin Front Arc (IBFA) and rhyolite from the Honshu Arc (HR). Comparison of the dispersed ash component to the discrete ash layers suggests that eruption frequency, rather than eruption size, drives the dispersed ash record. In contrast, at Site 52 Chinese Loess, IBFA, dispersed boninite from the Izu-Bonin arc, and a dispersed felsic ash of unknown origin are the sources. Interestingly, there are no boninite layers, yet boninite is dispersed within the sediment. Changes in the volcanic and eolian inputs through time indicate strong arc- and climate-related controls. The bulk sediment at Site C0011 is characterized by eolian dust, HR, and a dacite of unknown origin. Site C0012 is comprised of eolian dust, a dacite of unknown origin, as well as dacite and andesite from the Izu-Bonin Arc. Analysis of the total ash record at these two sites provides insight into subduction zone mass balance and water budgets as well as information about the changes in physical properties that result from the alteration of volcanic ash.

Les appareils d'acquisition d'image 3D sont désormais omniprésents dans plusieurs domaines scientifiques, dont l'imagerie biomédicale, la science des matériaux ou encore l'industrie. La plupart de ces appareils (IRM, scanners à rayons X, micro-tomographes, microscopes confocal, PET scans) produisent un ensemble de données organisées sur une grille régulière que nous nommerons des données digitales, plus couramment des pixels sur des images 2D et des voxels sur des images 3D. Lorsqu'elles sont bien récupérées, ces données approchent la géométrie de la forme capturée (comme des organes en imagerie biomédicale ou des objets dans l'ingénierie). Dans cette thèse, nous nous sommes intéressés à l'extraction de la géométrie sur ces données digitales, et plus précisément, nous nous concentrons à nous approcher des quantités géométriques différentielles comme la courbure sur ces objets. Ces quantités sont les ingrédients critiques de plusieurs applications comme la reconstruction de surface ou la reconnaissance, la correspondance ou la comparaison d'objets. Nous nous focalisons également sur les preuves de convergence asymptotique de ces estimateurs, qui garantissent en quelque sorte la qualité de l'estimation. Plus précisément, lorsque la résolution de l'appareil d'acquisition est augmenté, notre estimation géométrique est plus précise. Notre méthode est basée sur les invariants par intégration et sur l'approximation digitale des intégrations volumiques. Enfin, nous présentons une méthode de classification de la surface, qui analyse les données digitales dans un système à plusieurs échelles et classifie les éléments de surface en trois catégories : les parties lisses, les parties planes, et les parties singulières (discontinuités de la tangente). Ce type de détection de points caractéristiques est utilisé dans plusieurs algorithmes géométriques, comme la compression de maillage ou la reconnaissance d'objet. La stabilité aux paramètres et la robustesse au bruit sont évaluées en fonction des méthodes de la littérature. Tous nos outils pour l'analyse de données digitales sont appliqués à des micro-structures de neige provenant d'un tomographe à rayons X, et leur intérêt est évalué et discuté. / 3D image acquisition devices are now ubiquitous in many domains of science, including biomedical imaging, material science, or manufacturing. Most of these devices (MRI, scanner X, micro-tomography, confocal microscopy, PET scans) produce a set of data organized on a regular grid, which we call digital data, commonly called pixels in 2D images and voxels in 3D images. Properly processed, these data approach the geometry of imaged shapes, like organs in biomedical imagery or objects in engineering. In this thesis, we are interested in extracting the geometry of such digital data, and, more precisely, we focus on approaching geometrical differential quantities such as the curvature of these objects. These quantities are the critical ingredients of several applications like surface reconstruction or object recognition, matching or comparison. We focus on the proof of multigrid convergence of these estimators, which in turn guarantees the quality of estimations. More precisely, when the resolution of the acquisition device is increased, our geometric estimates are more accurate. Our method is based on integral invariants and on digital approximation of volumetric integrals. Finally, we present a surface classification method, which analyzes digital data in a multiscale framework and classifies surface elements into three categories: smooth part, planar part, and singular part (tangent discontinuity). Such feature detection is used in several geometry pipelines, like mesh compression or object recognition. The stability to parameters and the robustness to noise are evaluated with respect to state-of-the-art methods. All our tools for analyzing digital data are applied to 3D X-ray tomography of snow microstructures and their relevance is evaluated and discussed.

We prove that the non-k-equal configuration space of a graph has a discretized model, analogous to the discretized model for configurations on graphs. We apply discrete Morse theory to the latter to give an explicit combinatorial formula for the ranks of homology and cohomology of configurations of two points on a tree. We give explicit presentations for homology and cohomology classes as well as pairings for ordered and unordered configurations of two and three points on a few simple trees, and show that the first homology group of ordered and unordered configurations of two points in any tree is generated by the first homology groups of configurations of two points in three particular graphs, K_{1,3}, K_{1,4}, and the trivalent tree with 6 vertices and 2 vertices of degree 3, via graph embeddings.

Resumo: Neste trabalho é feito um estudo sobre os métodos de redução de ruído aditivo em sinais de voz baseados em wavelets e, através deste estudo, propõe-se um novo método de redução de ruído em sinais de voz no domínio wavelet. O princípio básico da maioria dos métodos de redução de ruído baseados em wavelets é a determinação e aplicação de um limiar, que permite bons resultados para sinais contaminados por ruído branco, mas não são eficientes no processamento de sinais contaminados por ruído colorido, que é o tipo de ruído mais comum em situações reais. Nesses métodos, o limiar, geralmente, é calculado nos intervalos de silêncio e aplicado em todo o sinal. Os coeficientes no domínio wavelet são comparados com este limiar e aqueles que estão abaixo deste valor são eliminados, fazendo assim uma aplicação linear deste limiar. Esta eliminação acaba causando descontinuidades no tempo e na freqüência no sinal processado. Além disso, a forma com que o limiar é calculado pode degradar os trechos de voz do sinal processado, principalmente nos casos em que o limiar depende fortemente da última janela do último trecho de silêncio. O método proposto neste trabalho também é baseado em corte por limiar, mas em vez de uma aplicação linear do limiar, ele faz uma aplicação não-linear, o que evita as descontinuidades causadas por outros algoritmos. O limiar é calculado nos trechos de silêncio e não depende apenas da última janela do último trecho de silêncio, mas sim de todas as janelas, já que este limiar é uma média de todos os limiares calculados neste trecho. Isto faz com que a redução do ruído seja mais uniforme e introduza menos distorções no sinal processado. Além disso, nos trechos de voz ainda é calculado um novo limiar que também será usado, em conjunto com o limiar calculado no silêncio. Isto faz com que a energia da janela que... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: In this work a study of additive noise reduction in speech based on wavelets is presented and, based on this study a new noise reduction method in speech in the wavelet domain is proposed. The basic idea of most methods of noise reduction based on wavelets is the determination and application of a threshold, that produces good results for signals contaminated by white noise, but they are not very efficient in processing signals contaminated by colored noise, which is more common in real situations. In those methods, the threshold, generally, is calculated in the silence intervals and applied to the whole signal. The coefficients in the wavelet domain are compared with this threshold and those that are below this value are eliminated, making a linear application of this threshold. This elimination causes discontinuities in time and frequency of the processed signal. Besides, the way that the threshold is computed can degrade the voice segments of the processed signal, principally when the threshold depends strongly on the last window of the last silence segment. The proposed method in this work is also based in thresholding, but, instead of a linear application of the threshold, it makes a non-linear application, which avoids the discontinuities caused by other algorithms. The threshold is calculated in the silence segments and is not dependent only on the last window of the last silence segment, but of all the windows, since this threshold is an average of all thresholds calculated in this segment. It makes noise reduction more uniform and introduces less distortion in the processed signal. Besides, in the voice segments a new threshold is calculated that will be also used with the threshold calculated in the silence. It makes that the energy of the window that is being processed is also considered. This way, it is... (Complete abstract, click electronic address below). / Orientador: Francisco Villarreal Alvarado / Coorientador: Jozué Vieira Filho / Banca: Carlos Roberto Minussi / Banca: Fernando Oscar Runstein / Banca: Roberto Kawakami Harrop Galvão / Banca: Ricardo Tokio Higuti / Doutor

Resumo: Neste trabalho é feito um estudo dos métodos de redução de ruído aditivo em sinais de voz baseados em wavelets e, através deste estudo, propõe-se um novo método não-limiar para redução de ruído em sinais de voz no domínio wavelet. Em geral os sinais de voz podem estar contaminados com ruídos artificiais ou reais. O problema consiste que dado um sinal limpo adiciona-se o ruído branco ou colorido, obtendo assim o sinal ruidoso, ambos no domínio do tempo. O que se propõe neste trabalho, é aplicar a transformada wavelet, obtendo assim o sinal transformado no domínio wavelet, reduzindo ou atenuando o ruído sem o uso de limiar. Os métodos mais usados no domínio wavelet são os métodos de redução por limiar, pois permitem bons resultados para sinais contaminados por ruído branco, mas não são eficientes no processamento de sinais contaminados por ruído colorido, que é o tipo de ruído mais comum em situações reais. Nesses métodos, o limiar, geralmente, é calculado nos intervalos de silêncio e aplicado em todo o sinal. Os coeficientes no domínio wavelet são comparados com este limiar e aqueles que estão abaixo deste valor são eliminados ou reduzidos, fazendo assim uma aplicação linear deste limiar. Esta eliminação, na maioria das vezes, causa descontinuidades no tempo e na frequência no sinal processado. Além disso, a forma com que o limiar é calculado pode degradar os trechos de voz do sinal processado, principalmente nos casos em que o limiar depende fortemente da última janela do último trecho de silêncio. O método proposto nesta pesquisa consiste na execução de três processamentos, agindo de acordo com as suas características nas regiões de voz e silêncio, sem o uso de limiar. A execução dos três processamentos é sintetizada numa única função, denominada de função de transferência, que atua como um filtro no processamento do sinal... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work a study of the methods for speech noise reduction based on wavelets is done and, through this study, a new non-thresholding method for speech noise reduction in the wavelet domain is proposed. Generally, a speech signal may be corrupted by artificial or real noise. Let a clean signal be corrupted by white or colored noise, rising a noisy signal in time domain. This work proposes the wavelet application to which gives rise to in the wavelet domain. In this domain, noise is reduced or attenuated without a threshold use. After, the signal is recomposed using the inverse discrete wavelet transform. The most used methods in the wavelet domain wavelet are the thresholding reduction methods, because they allow good results for signals corrupted by white noise, but they do not have the same efficiency when processing signals corrupted by colored noise, this is the most common noise in real situations. In those methods, the threshold is usually calculated in the silence intervals and applied to the whole signal. The coefficients in the wavelet domain are compared with this threshold and those that have absolute value below this value are eliminated or reduced, making a linear application of this threshold. This elimination causes discontinuities in time and in the frequency of the processed signal. Besides, the form with that the threshold is applied can degrade the voice segments of the processed signal, principally in cases that the threshold depends strongly on the last window of the last silence segment. The method proposed in this research consists in the execution of three processing, acting according to their characteristics in the voice and silence segments, without the threshold use. The three processing execution is synthesized in an unique function, called transfer function, acting as a filter in the signal processing. This method has as main objective the overcoming... (Complete abstract click electronic access below) / Orientador: Francisco Villarreal Alvarado / Coorientador: Jozué Vieira Filho / Banca: Carlos Roberto Minussi / Banca: Ailton Akira Shinoda / Banca: Jorge Diaz Calle / Banca: Leandro de Campos Teixeira Gomes / Doutor

A produção brasileira de cana-de-açúcar foi de cerca de 426 milhões de toneladas na safra 2006/2007, tendo o estado de São Paulo participado com aproximadamente 264 milhões desse total. Esses valores conferem ao país a posição de maior produtor mundial de cana-de-açúcar, comprovando a importância do setor sucroalcooleiro na economia brasileira. As paradas na indústria açucareira, caracterizadas pela interrupção da produção por falta de matéria-prima, podem afetar negativamente a qualidade do produto final. Para que o abastecimento de cana na moenda seja feito de forma contínua é importante que o dimensionamento da frota para execução das operações de corte, carregamento e transporte (CCT) da cana-de-açúcar, até a entrega dela na usina, seja realizado de forma criteriosa, sob pena de se incorrer em elevado custo operacional. Estas operações podem ser executadas de diversas maneiras, variando parâmetros desde o tipo de corte (corte manual ou mecanizado) como o tipo de equipamento utilizado (carregadoras, colhedoras, tratores-reboque, etc.). Devido à interdependência dos processos, é possível a ocorrência de tempos não produtivos (filas) nos locais de carregamento e descarga, justamente pela quantificação desbalanceada dos recursos ou devido à variabilidade dos tempos de processo. Este trabalho aborda o problema de dimensionamento da frota de equipamentos utilizados no CCT, utilizando-se a técnica de simulação de eventos discretos. Este problema consiste, basicamente, em determinar a quantidade de equipamentos necessários ao cumprimento das operações citadas, de forma a maximizar a produção do sistema como um todo, minimizando o custo operacional. Foi desenvolvido um modelo de simulação que representa com fidelidade as operações de uma usina de cana-de-açúcar com capacidade de moagem de 19.500 t/dia. Investigou-se necessidade de equipamentos frente a diferentes políticas de despacho da frota de caminhões, comparando o despacho estático de conjuntos de caminhões por frente de corte versus despacho Dinâmico; avaliou-se também a adoção de sistema drop and hook (D&H) para as composições de transporte. O modelo desenvolvido foi capaz de mostrar como as decisões logísticas afetam a produtividade da frota e, conseqüentemente, o custo do sistema. O cenário com despacho dinâmico e sem adoção de D&H apresentou o melhor resultado de custo operacional. Os resultados indicaram também que a adoção de reboques reserva na lavoura é economicamente viável. Como o modelo é bastante flexível quanto às configurações de cenários, outras combinações de fatores podem ser avaliadas. / The Brazilian production of cane sugar was around 426 million tonnes in the 2006/2007 season, the state of São Paulo participated in about 264 million from that sum. These figures give the country the position of the world\'s largest sugar cane producer , showing the importance of sugar-alcohol section in the Brazilian economy. The halts on the sugar industry, characterized by the interruption of production due to the lack of raw material, may adversely affect the quality of the final product. For the supply of cane in the milling to be done on a continuous way, it is important that the size of the fleet which runs the cutting, loading and transportation of sugar cane (CCT) operations up to its delivery in the mill- is carried out carefully, under penalty of incurring high operational costs. These operations might be implemented in different ways, ranging parameters from the kind of cut (manual or mechanical cutting) as the kind of equipment (loaders, harvesters, tractors, trailers, etc.). Due to the interdependence in the processes, it is possible the occurrence of non-productive time (queues) in place of loading and unloading, due to unbalanced quantifying of resources or due to the variability of time during the process. This paper approaches the problem of the equipment fleet sizing used in the CCT, using the simulation of discrete events technique. This problem consists in determining the necessary amount of equipment to perform the above operations, in order to maximize the production of the system as a whole, minimizing the operational costs. We developed a simulation model that represents with accuracy the operations of a sugar cane plant with a milling capacity of 19,500 ton / day. The need for equipments facing different political dispatch from the fleet of trucks has been investigated, by comparing the dispatch of Static sets of trucks for each cutting front versus dynamic dispatch and the use of drop and hook system (D & H) for the transportation setting. The developed model was able to show how the logistics decisions affect the fleet productivity and, consequently, the cost of the system. The scenario with dynamic dispatch and no D & H use had the best results of operational costs. The results also indicated that the use of backup trailers in farming is economically viable. As the model is quite flexible concerning scenario settings , other combinations of factors can be evaluated.

Discreto e contínuo são termos que se referem respectivamente a duas das ações básicas na elaboração da Matemática: contar e medir. Neste trabalho examinamos o problema pedagógico que surge da tendência de se abordar os temas de Matemática elementar optando por um ou outro aspecto, sem explorar a interação entre eles. Nossa ideia é que isso se resolve através da administração da tensão conceitual entre essas noções. Trata-se de caminhar com ambas as pernas, a da ideia do discreto e a da continuidade, na construção dos conceitos matemáticos. Este trabalho é baseado na pesquisa em História da Matemática, justificada pela visão do conhecimento como uma rede conceitual, uma rede de significações em permanente transformação. Procuramos assim fazer uso da História para repensar aspectos do ensino de Matemática elementar, especialmente relacionados ao nosso tema: a construção da ideia de Número; o nascimento do Cálculo Diferencial e Integral; as relações entre qualidade/quantidade. Ao final, mostramos exemplos de Oficinas Temáticas para a formação de professores, nas quais procuramos aplicar a abordagem histórica visando administrar o par conceitual discreto/contínuo dentro de assuntos do currículo elementar de matemática. / Discrete and continuous are concepts related respectively to two basic actions in Mathematics: to count and to measure. In this work we examine the pedagogical problem originated in the tendency of approaching elementary Mathematics by making an option between either one or other feature, without exploring the relationship between them. Our idea is that it can be solved by managing the conceptual tension between those notions. It is a matter of getting along with both ideas, the discreteness and the continuity, in the construction of mathematical concepts. The present work is based on Mathematics History research, justified by the image of knowledge as a conceptual net, a net of meanings which always change. We make use of the History to think over certain features of Mathematics elementary teaching specially meaningful to our work: the construction of the idea of Number, the birth of the Differential and Integral Calculus, the relationship between quality and quantity. At last, we show examples of Thematical Workshops to teachers training, in which our aim is to apply the historical approach in order to deal with the conceptual pair discrete/continuous in topics of the mathematical elementary curriculum.

Este trabalho cria um modelo, em simulação a eventos discretos, utilizando o software ARENA 5.0, do centro de distribuição de peças de uma empresa do ramo automotivo, para geração de informações relacionadas ao deslocamento dos funcionários nos corredores. Existem diversas variáveis que estão diretamente relacionadas à movimentação no processo de retirada de itens, tais como capacidade e velocidade do transportador manual, influência do peso dos itens na coleta, dentre outras, que dificultam o processo de tomada de decisão. As técnicas propostas na bibliografia apresentam dificuldades em fornecer soluções já que não são capazes de trabalhar simultaneamente com estas variáveis, apresentando, assim, resultados discrepantes com a realidade. A simulação permite lidar com tais variáveis e fornecer resultados que servirão de suporte aos decisores para a tomada de decisão e assim gerenciar melhor os funcionários para completar a coleta de itens dos pedidos sem atrasos / This work builds a model, by the discrete event simulation, using the software ARENA 5.0, of a parts distribution centre of an automotive company, to generate information related to employees routing in aisles. There are several variables related to the movement in the retrieving process, such as capacity and velocity of the manual trolley, influence of the mass of items in the collecting process, among others, which make the decision process difficult. The techniques found in the literature demonstrate certain difficulties in providing solutions because they are not capable of dealing with those variables simultaneously, presenting, consequently, discrepancy results to the reality. The simulation permits to deal with those variables simultaneously and proving results to support managers in decisions and, therefore, to improve employees management in order to finalize the collecting of items without delay

A proposta do trabalho é criar um modelo de simulação híbrida capaz de representar um sistema logístico. Partindo de uma investigação bibliográfica conceitual das metodologias de simulação de eventos discretos e da metodologia de simulação contínua (System Dynamics) capaz de revelar suas características principais e seus potenciais de aplicabilidade, é possível delinear as possibilidades de contribuição de ambas as metodologias para o desenvolvimento de modelos híbridos (metodologias discreta + contínua) de simulação. O modelo híbrido é desenvolvido sob a plataforma AnyLogic, e a integração adequada de ambas as metodologias no modelo criado é capaz de expandir o espectro de compreensão do sistema, com a possibilidade de integração de aspectos físicos e dimensionais a aspectos políticos e comportamentais do sistema em estudo, apresentando-se como ferramenta poderosa para sobrevivência às exigentes demandas concorrenciais. / This study aims at creating a hybrid simulation model able to properly represent a logistics system. Departing from a conceptual literature review about the discrete-event and the continuous (System Dynamics) simulation methodologies able to reveals its main features and potential of applicability, it is possible to define the possibilities of developing hybrid (discrete + continuous) simulation models. The proper integration of both methodologies in a hybrid model allows the expansion of the comprehension spectrum of the system, with the possibility of integrating the physical and dimensional aspects to political and behavior patterns, revealing the hybrid methodology as a powerful tool to succeed in the highly demanding business world.

Thesis advisor: Andrew Beauchamp / Thesis advisor: Peter Gottschalk / This dissertation examines how caregiving for an elderly parent affects an adult child's labor supply and wages. In the first chapter (co-authored with Courtney H. Van Houtven and Norma B. Coe) we identify the relationship between informal care and labor force participation in the United States, both on the intensive and extensive margins, and examine wage effects. We control for time-invariant individual heterogeneity; rule out or control for endogeneity; examine effects for men and women separately; and analyze heterogeneous effects by task and intensity. We find modest decreases--1.4-2.4 percentage points--in the likelihood of working for caregivers providing personal care. Male and female chore caregivers, meanwhile, are more likely to retire. For female care providers who remain working, we find evidence that they decrease work by 3-10 hours per week and face a 2.3-2.6 percent wage penalty. We find little effect of caregiving on working men's hours or wages except for a wage premium for male intensive caregivers. In the second chapter I formulate and estimate a dynamic discrete choice model of elder parent care and work to analyze how caregiving affects a woman's current and future labor force participation and wages. Intertemporal tradeoffs, such as decreased future earning capacity due to a current reduction in labor market work, are central to the decision to provide care. The existing literature, however, overlooks such long-term considerations. I depart from the previous literature by modeling caregiving and work decisions in an explicitly intertemporal framework. The model incorporates dynamic elements such as the health of the elderly parent, human capital accumulation and job offer availability. I estimate the model on a sample of women from the Health and Retirement Study by efficient method of moments. The estimates indicate that intertemporal tradeoffs matter considerably. In particular, women face low probabilities of returning to work or increasing work hours after a caregiving spell. Using the estimates, I simulate several government sponsored elder care policy experiments: a longer unpaid leave than currently available under the Family and Medical Leave Act of 1993; a paid work leave; and a caregiver allowance. The leaves encourage more work among intensive care providers since they guarantee a woman can return to her job, while the caregiver allowance discourages work. A comparison of the welfare gains generated by the policies shows that half the value of the paid leave can be achieved with the unpaid leave, and the caregiver allowance generates gains comparable to the unpaid leave. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.