Este trabalho aborda os conceitos necessários para o estudo de tolerâncias dimensionais de um conjunto mecânico e propõe um método eficaz para a especificação de tolerâncias na fase de detalhamento do projeto de um produto, através de um algoritmo de otimização baseado em custos de produção. Conceitos do custo da perda de qualidade desenvolvidos por Genichi Taguchi são também aplicados para a especificação de restrições funcionais, que visam garantir um determinado nível de qualidade em função de valores especificados para critérios funcionais. Comentários e comparações com outros trabalhos de otimização de tolerâncias dimensionais são também realizados, através dos quais podem ser observadas características específicas no método proposto. Um exemplo de aplicação é apresentado através do estudo de caso baseado em um projeto de sistema de transmissão de potência por correias a equipamentos periféricos de um motor de combustão interna. Os resultados da aplicação do algoritmo de otimização são comparados aos de métodos convencionais de síntese de tolerâncias, mostrando sua eficácia. / This work approaches the concepts needed to the study of dimensional tolerances of a mechanical assembly and proposes an effective method for specifying tolerances in the detailing phase of product design, by means of an optimization algorithm based on manufacturing costs. Concepts of quality loss developed by Genichi Taguchi are also applied for specifying functional constraints, which aim to assure an adequate quality level regarding specified values of functional criteria. Comments and comparisons with other dimensional tolerances optimization works are also made, through which specific features of the proposed method can be observed. An application example of the method is presented through a case study based on a belt power transmission system to ancillary equipment of an internal combustion engine. Results of application of the optimization algorithm are compared with the ones of conventional tolerance synthesis methods, showing their effectiveness.

University of Macau / Faculty of Science and Technology. / Department of Computer and Information Science

Orientador: Josineudson Augusto II de Vasconcelos Silva / Coorientador: Daniela Andressa Lino Lourenço / Coorientador: Joslaine Noely dos Santos Gonçalves Cyrillo / Banca: Danísio Prado Munari / Banca: Nedênia Bonvino Stafuzza / Banca: Rusbel Raul Aspilcueta Borquis / Resumo: A disponibilidade de painéis de polimorfismos de nucleotídeos únicos (SNPs) a baixo custo tem viabilizado estudos genômicos em espécies de interesse econômico. Os objetivos do presente estudo foram conduzir análises de estruturação da população e assinaturas de seleção em duas populações de bovinos Gir selecionadas para diferentes critérios de seleção (corte ou leite); e investigar se a estimativa do efeito materno para característica medida na progênie apresenta maior acurácia com uso de "pool" de sêmen e informação genômica em diferentes cenários simulados de suínos. Análise de componentes principais (PCA) e Análise Discriminante de Componentes Principais (DAPC) foram utilizadas para verificar a estrutura da população nas populações Gir analisadas, e três métodos diferentes foram utilizados na detecção de assinaturas de seleção: índice de fixação (Fst), Escore de Integração dos Haplótipos (iHS) e Homozigose do Haplótipo Estendido Entre Populações (XP-EHH). Diferenciação genética entre as duas populações de bovinos foi observada nos resultados de PCA e DAPC. Um total de 282 genes foram identificados sob seleção, com base nos testes Fst, iHS e XP-EHH, dos quais 35 genes estão associados com QTL previamente descritos em bovinos. Os padrões de variação genética nos bovinos Gir foram consistentes com a presença de pressões seletivas em algum momento na história das populações de corte e leite. Estes resultados fornecem informações complementares sobre regiões genômicas de intere... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The availability of commercial SNP panels at a low cost has made it possible the application of genomic studies in domestic species. The aim of this study was to conduct population structure and signatures of selection analyzes in two populations of Gir cattle selected for different criteria (beef or dairy); and to investigate whether maternal direct effect for litter birth weight can be improved when pooled semen and genomic information are used in different simulated scenarios in pigs. Principal Component Analysis (PCA) and Discriminant Analysis of Principal Components (DAPC) were used to verify population structure in the studied Gir cattle populations, and three different methods were used to detect signatures of selection: fixation index (Fst), Integrated Haplotype Score (iHS), and Cross-Population Extend Haplotype Homozygosity (XP-EHH). Genetic differentiation between the two cattle populations was observed in the PCA and DAPC results. A total of 282 genes were identified under selection based on the Fst, iHS and XP-EHH tests, of which 35 genes are associated with QTL previously described in cattle. The patterns of genotypic variation in Gir cattle were consistent with the presence of selective pressures at some point in the history of the beef and dairy populations. These findings can provide complementary information on genomic regions of interest for functional genomic studies, genome-wide associations, and the implementation of breeding schemes aiming genetic improv... (Complete abstract click electronic access below) / Doutor

A madeira é um material de origem biológica, renovável, com papel importante no ciclo do carbono, que contribui para o desenvolvimento sustentável. As madeiras tropicais brasileiras são apreciadas na indústria da construção civil em peças estruturais, componentes de edificação e mobiliário. A melhor utilização da matéria-prima nos diversos processos depende do conhecimento das suas propriedades, e nesse aspecto, os estudos sobre estabilidade dimensional são escassos, em sua maioria, desenvolvidos para coníferas do hemisfério Norte. Este trabalho tem como objetivo geral aprofundar o estudo da estabilidade dimensional, trabalhando com propriedades físicas de madeiras tropicais brasileiras, com ênfase nas densidades, ponto de saturação das fibras, retratibilidade e inchamento. Utilizando madeira de quinze espécies tropicais brasileiras, foram realizados ensaios, de acordo com a NBR 7190/97 para determinar: densidade aparente 0% e 12% de umidade, densidade básica, ponto de saturação das fibras, retração, inchamento, coeficiente de anisotropia, coeficiente de retratibilidade volumétrica e coeficiente de inchamento volumétrico. Investigaram-se as relações entre as propriedades determinadas de modo a poder inferir sobre: a estabilidade dimensional baseando-se nas densidades; as precisões de relações desenvolvidas em pesquisas correlatas. Além disso, foi desenvolvida (e investigada sua precisão, ao nível de significância 5%) uma relação entre densidade básica e densidade aparente via retratibilidade/inchamento. De acordo com os resultados, o melhor coeficiente de determinação ajustado atingido na tentativa de relacionar densidades com os parâmetros da estabilidade dimensional foi 19,58% indicando que a densidade não é um bom estimador da estabilidade dimensional da madeira. Algumas das relações desenvolvidas em pesquisas correlatas não foram consideradas válidas, de acordo com a análise estatística. Para a relação desenvolvida no presente trabalho, embora a mesma apresente média e coeficiente de variação próximos aos dos resultados experimentais, a análise de representatividade não confirmou sua significância. / Wood is an organic and renewable material, with important role in carbon cycle, which contributes to sustainable development. Brazilian tropical woods are considered in building industry in structural ant other components and in furniture. The better use of raw materials in different processes depends on knowledge of their properties and, in this respect, studies of dimensional stability are scarce, mostly developed for Northern Hemisphere conifers. This work aims to extend the study of dimensional stability, now working with physical properties of Brazilian tropical woods, emphasizing densities, fiber saturation point; shrinkage and swelling. Using wood of fifteen Brazilian tropical species, tests were carried out, according to NBR 7190/97 to determine: density (0% and 12% moisture content); basic density; fiber saturation point; shrinkage; swelling; anisotropy coefficient; volumetric shrinkage coefficient; and volumetric swelling coefficient. Correlations between certain properties were investigated in order to be able to infer: dimensional stability based on densities; precision of relationships developed in related research. Furthermore, it was developed (and investigated their accuracy, 5% significance level) a relationship between specific gravity and bulk density via shrinkage/ swelling. According to results, the best determination coefficient, obtained in attempt to correlate density with parameters of dimensional stability, was 19.58%. This indicates that density is not a good estimator of dimensional stability for tropical wood. Based on statistical analysis, some of the relationships developed in related researches were not considered valid. For the relationship developed in this research, although it presents average and coefficient of variation close to experimental results, analysis of accuracy did not confirm its significance.

Three dimensional (3-D) seismic reflection surveying is accepted as the preferred method for imaging complex geology for proving and developing commercial oil and gas fields. However, the cost of 3-D seismic recording and processing is substantial and often can be as expensive as the cost of production drilling. This is particularly the case for land oil field development, where the cost of 3-D surveying is often unacceptably high. Such high costs also restrict its application in coal exploration, where 2-D seismic methods have long been accepted.During the early 1980's, a low fold technique for recording land 3-D data was devised which offered significant cost savings. The technique was adapted by the author for land 3-D surveying over coal fields. Inherent in the technique was a requirement that the data must have a high signal-to-noise ratio, which is not generally the case in land surveying due to the presence of strong source generated surface wave noise. A further major impediment to the technique was its inability to perform an acceptable stacking velocity analysis because of the low number of seismic traces generated. This thesis defines three data collection and processing advancements in low fold 3-D technology which go some way towards resolving these impediments.The first advancement is a method to enhance the signal-to-noise ratio of the stacked seismic data, and consists of a Radon-based transform which stacks shot domain data along a curved trajectory, thereby attenuating surface waves on swath recorded data. This transform is termed the 'Radial Transform' of 3-D data.The second advancement is a statics method to improve the stacked image from a low number of input traces. The method uses the concept that if both the reflected and refracted waves pass through a weathering layer with very similar travel paths, then static corrections to remove the ++ / effects of weathering variations on the refraction travel times would be very similar to those required for the reflections. This method, which was patented, is used equally for both 2-D and 3-D field data, and is regularly used in high resolution seismic processing for coal at Curtin University.The third advancement resolves the problem of azimuthal variation of stacking velocities. By predicting the true reflector dip and its azimuth, apparent dip can be included in the normal moveout equation, which is named the Generalized Moveout equation. The requirement for an azimuthally dependent stacking velocity is then no longer an impediment in low fold 3-D processing of coal data.After developing these transforms and applying them to synthetic data, they were tested with success on modelled field data. All field data used within this thesis were either recorded in the field by the author, or were produced with a physical modelling system, which was built by the author at the University of Houston and later at Curtin University.Results indicate that the procedures described in this thesis enable the low fold 3-D technique to be used as a viable method for recording seismic data when survey economics are a major issue. Furthermore, all three advancements are suitable for application in conventional two dimensional (2-D) and swath seismic surveying.

Upon dimensional reduction, certain supergravity theories exhibit symmetries otherwise undetected, called hidden symmetries. Not only do these symmetries teach us about the structure of the corresponding theories but moreover they provide methods to construct black hole solutions. In this thesis, we study the hidden symmetries of supergravity theories of particular interest and how these help constructing black hole solutions in dimensions D>4. We focus on three representative cases that are the symmetries appearing upon dimensional reduction to three, two and one dimensions. They are respectively described by finite, affine and hyperbolic algebras. In the first two cases, we develop and apply solution generating techniques. The first part of this thesis introduces the background concepts. We start with an introduction to black holes and other black objects in dimensions D>4. We present their subtleties, the known solutions and the conjectured ones. We insist on stationary axisymmetric solutions of vacuum and to the corresponding solution generating technique. The next chapter gives an introduction to Kac-Moody algebras. These indeed play a central role in this thesis as the symmetries appearing in three, two and one dimensions are described by three types of Kac-Moody algebras called respectively finite, affine and hyperbolic. In the second part, we first review the notion of dimensional reductions and how the hidden symmetries can be uncovered. The rest of the thesis contains three applications of these hidden symmetries. The first two concern five-dimensional minimal supergravity. Upon dimensional reduction to three dimensions, this theory exhibits a symmetry under the exceptional finite Kac-Moody algebra g2. This 14-dimensional algebra is the smallest exceptional finite Kac-Moody algebra. We use this duality to generate solutions while focussing mainly on black strings. After reduction to two dimensions, the symmetry becomes infinite-dimensional and is described by the affine extension of g2. Moreover, the two-dimensional theory is integrable, which allows us to develop another type of solution generating technique, hitherto applied only to vacuum gravity. In this work we generalize it to a case with matter fields. Finally, the notion of dimensional reduction to one dimension provides the necessary intuition for the conjecture of an algebraic formulation of M-theory, candidate to the unification of all interactions, based on the hyperbolic Kac-Moody algebra e10. In the last chapter of this thesis, we study an aspect of this correspondence, namely the e10 symmetry of massive type IIA supergravity in ten dimensions. / On sait depuis longtemps que par un processus appelé réduction dimensionnelle, on peut faire apparaître dans certaines théories de gravitation des symétries autrement indétectées. On les appelle des symétries cachées. La mise en évidence de ces symétries non seulement nous informe sur la structure de ces théories, mais de plus elle permet d'élaborer des méthodes de construction de solutions de trous noirs. Dans cette thèse, nous étudions les symétries cachées de certaines théories de supergravité en dimensions supérieures à quatre. Nous nous concentrons sur trois cas représentatifs que sont les symétries apparaissant après réduction à trois, deux et une dimensions. Dans les cas des symétries apparaissant à trois et à deux dimensions nous développons et appliquons des méthodes de construction de solutions. La première partie introduit les concepts préliminaires. Nous commençons par une introduction aux trous noirs et autres objets noirs en dimensions supérieures à quatre. Nous en présentons les subtilités, les solutions connues à ce jour et celles qui ne sont encore que conjecturées. Nous insistons particulièrement sur les solutions stationnaires à symétrie axiale dans le vide et à la méthode de construction de solutions correspondante. Le chapitre suivant présente une introduction aux algèbres de Kac-Moody. Celles-ci jouent en effet un rôle central dans cette thèse puisque les symétries apparaissant à trois, deux et une dimensions sont décrites par trois types d'algèbres de Kac-Moody appelées respectivement finies, affines et hyperboliques. Dans la deuxième partie, nous rentrons dans le vif du sujet, en commençant par rappeler le principe des réductions dimensionnelles et la mise en évidence des différents types de symétries cachées. Les trois derniers chapitres contiennent ensuite trois applications de ces symétries cachées. Dans deux d'entre eux, nous nous concentrons sur la théorie de supergravité minimale à cinq dimensions. Après réduction à trois dimensions, cette théorie présente un symétrie cachée sous le groupe G2 qui, avec quatorze dimensions, est le plus petit des groupes de Lie exceptionnels. Nous utilisons cette dualité pour engendrer des solutions, en nous focalisant essentiellement sur les solutions de cordes noires. A deux dimensions, la symétrie est décrite par l'extension affine de G2. De plus, la théorie est alors complètement intégrable. Cela conduit à un autre type de méthode de construction de solutions, jusqu'alors uniquement appliquée à des théories dans le vide. Dans ce travail, nous la généralisons donc à un cas avec champs de matière. Enfin, la notion de réduction à une dimension fournit l'intuition d'une conjecture selon laquelle la théorie M, candidate à l'unification de toutes les interactions, pourrait être reformulée en une théorie basée sur l'algèbre de Kac-Moody hyperbolique e10. Dans le dernier chapitre de cette thèse, nous étudions un aspect de cette correspondance, à savoir, la symétrie sous e10 de la supergravité massive de type IIA à dix dimensions.

Thesis (M.S. in Modeling, Virtual Environments and Simulation)--Naval Postgraduate School, September 2003. / Thesis advisor(s): Christian J. Darken, Joseph A. Sullivan. Includes bibliographical references (p. 91-92). Also available online.

Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Allen R. Tannenbaum; Committee Member: Anthony J. Yezzi; Committee Member: Gregory Turk; Committee Member: Joel R. Jackson; Committee Member: Patricio A. Vela

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [89]-98).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains x, 220 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 69-74).