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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Modelo de calibração ultraestrutural / Ultrastructural calibration model

Alina Marcondes Talarico 23 January 2014 (has links)
Os programas de Ensaios de Prociência (EP) são utilizados pela sociedade para avaliar a competência e a confiabilidade de laboratórios na execução de medições específicas. Atualmente, diversos grupos de EP foram estabelecidos pelo INMETRO, entre estes, o grupo de testes de motores. Cada grupo é formado por diversos laboratórios que medem o mesmo artefato e suas medições são comparadas através de métodos estatísticos. O grupo de motores escolheu um motor gasolina 1.0, gentilmente cedido pela GM Powertrain, como artefato. A potência do artefato foi medida em 10 pontos de rotação por 6 laboratórios. Aqui, motivados por este conjunto de dados, estendemos o modelo de calibração comparativa de Barnett (1969) para avaliar a compatibilidade dos laboratórios considerando a distribuição t de Student e apresentamos os resultados obtidos das aplicações e simulações a este conjunto de dados / Proficiency Testing (PT) programs are used by society to assess the competence and the reliability in laboratories execution of specific measurements. Nowadays many PT groups were established by INMETRO, including the motor\'s test group. Each group is formed by laboratories measuring the same artifact and their measurements are compared through statistic methods. The motor\'s group chose a gasoline engine 1.0, kindly provided by GM as an artifact. The artifact\'s power was measured at ten points of rotation by 6 laboratories. Here, motivated by this set data, we extend the Barnet comparative calibration model (1969) to assess the compatibility of the laboratories considering the Student-t distribution and show the results obtained from application and simulation of this set data
32

Uma abordagem da distribuição normal através da resolução de uma situação problema com a utilização do software Geogebra / A normal dsitribution approach through the resolution of a problem situation using the Geogebra software

Gonçalves, Paulo Henrique Rodrigues 24 October 2014 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-26T10:53:11Z No. of bitstreams: 2 Dissertação - Paulo Henrique Rodrigues Gonçalves - 2014.pdf: 5144667 bytes, checksum: a888421e690cbbc6b7b5c585dee8115c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-26T11:00:07Z (GMT) No. of bitstreams: 2 Dissertação - Paulo Henrique Rodrigues Gonçalves - 2014.pdf: 5144667 bytes, checksum: a888421e690cbbc6b7b5c585dee8115c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-26T11:00:07Z (GMT). No. of bitstreams: 2 Dissertação - Paulo Henrique Rodrigues Gonçalves - 2014.pdf: 5144667 bytes, checksum: a888421e690cbbc6b7b5c585dee8115c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-10-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Normal Distribution, also known as the Gaussian bell curve, is a mathematical model used to describe a compound of values and one of its main uses is providing an estimate about the mean of the compound. The Normal Distribution is essential for the statistical inference; yet, it is rarely studied during high school, being more commonly included in high education course outlines more specifically inside disciplines related to probability and statistics. The PCNs (National Curriculum Parameters) highlight the teaching’s relevance of inference techniques about a population through the evidences provided by a sample. This study proposes a Normal Distribution approach through the resolution of a problem situation with the aid of the Geogebra software to be applied to a veterans’ high school group. By reaching the resolution of this problem, the students will be motivated to estimate the mean weight of the mass of 40 kilograms of oranges to (considering this information) estimate the number of oranges contained in the mass. The students will also be able to determine the amount of oneliter juice boxes that could be produced from it. The methodology used was bibliographic research and contextualization. The presented work is pure theoretical which final product is a purpose to teach the Normal Function, working with the Geogebra software. / A Distribuição Normal ou curva de Gauss é um modelo matemático usado para descrever um conjunto de valores e uma das suas principais utilidades é fornecer uma estimação sobre a média desse conjunto. A Distribuição Normal é essencial para a inferência estatística, no entanto, raramente é vista no Ensino Médio, sendo mais comum em currículos de cursos de graduação em disciplinas de probabilidade ou estatística. Os PCNs destacam a relevância do ensino de técnicas de inferência sobre uma população através de evidências fornecidas por uma amostra. Este trabalho propõe uma abordagem da Distribuição Normal através da resolução de uma situação problema com auxílio do software Geogebra a ser aplicada numa turma de terceiro ano do Ensino Médio. Na resolução dessa situação problema os alunos serão motivados a estimar o peso médio de massa de quarenta quilos de laranjas pera para, através desta informação, estimar o número de laranjas contidas nessa massa e determinar a quantidade de caixas de um litro de suco que podem ser produzidas. A metodologia usada neste trabalho trata-se de pesquisa bibliográfica e contextualização. O trabalho apresentado é de caráter teórico cujo produto final é uma proposta para ensinar a Função Normal articulando com o software Geogebra.
33

Explicit Estimators for a Banded Covariance Matrix in a Multivariate Normal Distribution

Karlsson, Emil January 2014 (has links)
The problem of estimating mean and covariances of a multivariate normal distributedrandom vector has been studied in many forms. This thesis focuses on the estimatorsproposed in [15] for a banded covariance structure with m-dependence. It presents theprevious results of the estimator and rewrites the estimator when m = 1, thus makingit easier to analyze. This leads to an adjustment, and a proposition for an unbiasedestimator can be presented. A new and easier proof of consistency is then presented.This theory is later generalized into a general linear model where the correspondingtheorems and propositions are made to establish unbiasedness and consistency. In thelast chapter some simulations with the previous and new estimator verifies that thetheoretical results indeed makes an impact.
34

Vibration-based damage detection in structures

Asnaashari, Erfan January 2014 (has links)
Structural health monitoring systems have a great potential for cost saving and safety improvement in different types of structures. One of the most important tasks of these systems is to identify damage at an early stage of its development. A variety of methods may be used to identify, locate, or quantify the extent of damage or fault in a structural or mechanical component. However, the preferable method is the one which maximises the probability of detecting the flaw, while also considering feasibility of in-situ testing, ease of use and economic factors. Cracks are one of the common defects in structural components that may ultimately lead to failure of structures if not detected. The presence of cracks in a structure brings about local variations in the stiffness of the structure. These variations cause the dynamic behaviour of the cracked structure to be different from that of a healthy one. Vibration-based damage detection methods have attracted considerable attention over the past few decades. These methods generally use changes to the physical properties of structures for the purpose of crack detection. In this thesis, two new vibration-based methods have been developed for damage detection in beam-like and rotor-type structures. The first method performs the entire signal processing required for crack detection in time domain. It is based on assessing the normality of vibration responses using the normal probability plot (NPP). The amount of deviation between the actual and normal distribution of measured vibration responses was calculated along the length of the structure to localise the crack. The second proposed method converts the vibration responses into frequency domain for further processing. Excitation of the cracked structure at a given frequency always generates higher harmonic components of the exciting frequency due to the breathing of the crack. This method uses the operational deflection shape of the structure at the exciting frequency and its higher harmonics to identify the crack location. Avoiding complicated signal processing in frequency domain is the main advantage of the first method. However, more precise identification of crack locations can be obtained through the second method. Generally, both methods have the advantage of being easy, reference-free and applicable to in-situ testing for any structure. The concept and computational approach of both methods along with their validations through numerical and experimental examples have been presented. Moreover, different input excitations have been used to evaluate the capability of the developed methods in detecting the crack location(s).
35

Inferences about Parameters of Trivariate Normal Distribution with Missing Data

Wang, Xing 05 July 2013 (has links)
Multivariate normal distribution is commonly encountered in any field, a frequent issue is the missing values in practice. The purpose of this research was to estimate the parameters in three-dimensional covariance permutation-symmetric normal distribution with complete data and all possible patterns of incomplete data. In this study, MLE with missing data were derived, and the properties of the MLE as well as the sampling distributions were obtained. A Monte Carlo simulation study was used to evaluate the performance of the considered estimators for both cases when ρ was known and unknown. All results indicated that, compared to estimators in the case of omitting observations with missing data, the estimators derived in this article led to better performance. Furthermore, when ρ was unknown, using the estimate of ρ would lead to the same conclusion.
36

A Geometry-Based Multiple Testing Correction for Contingency Tables by Truncated Normal Distribution / 切断正規分布を用いた分割表の幾何学的マルチプルテスティング補正法

Basak, Tapati 24 May 2021 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第23367号 / 医博第4736号 / 新制||医||1051(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 森田 智視, 教授 川上 浩司, 教授 佐藤 俊哉 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
37

A Study on Distribution Learning of Generative Adversarial Networks

Liu, Jiaping 27 October 2020 (has links)
This thesis is an exploration of the properties of shallow generative adversarial networks (GANs). We focus on several aspects of GANs to investigate the learnability of a class of distributions using shallow GANs and conduct experiments to explore the influence of these aspects on the performance of the GAN models. We identify and analyze several pathological phenomena in theoretical analysis and experiments, and propose potential solutions for them.
38

Probable Circular Error (CEP) of Ballistic Missiles

Moran, James Edward, Jr. 01 May 1966 (has links)
The survival of our nation, during a nuclear exchange, depends upon an effective national defense structure. The prime weapon system in this defense structure is the ballistic missile. Although many factors enter into an evaluation of the effectiveness of a ballistic missile, one of the most important measure is accuracy. Without an accurate weapon system we have no weapon system. The Department of Defense has places emphasis on using a method of accuracy evaluation called "Probably Circular Error (CEP)." Probably Circular Error is defined as "The radius of a circle, centered at the intended target, within which 50% of the missiles would be expected to impact" or "The probability is 0.50 that an individual missile will impact within a circle whose radius is equal to the CEP." The statistical techniques and assumptions used in generation a CEP value will be investigated.
39

Bolstering Pine Lumber Value Through Statistical Analysis And Nondestructive Testing

Owens, Frank Charles, IV 11 August 2017 (has links)
In or around 2010, a nationwide reevaluation of the allowable properties for southern pine dimension lumber was initiated. This led to a 2013 reduction in the design values of visually graded southern pine dimension lumber and a resulting decrease in its commercial and utility value. This change compelled researchers and industry professionals to ponder what could be done to shore up the value of solid-sawn southern pine products going forward and potentially increase design values if appropriate. In pursuit of this question, this dissertation looks closely at three areas: 1) the possibility this reduction in mechanical performance is not merely limited to southern pine structural lumber but can also be observed in other solid-sawn softwood products and species, 2) flaws that might exist in commonly utilized statistical models for estimating allowable properties in lumber, and 3) the feasibility of using existing technologies to begin to compensate for the economic and/or utility losses attributed to the recent reduction in design values. This work is comprised of an introduction, a conclusion, and three independent content chapters utilizing a variety of statistical techniques to investigate whether strength and stiffness reduction might also be occurring in southern pine (and Douglasir) utility crossarms, evaluate the propriety of using a Weibull distribution model for estimating allowable properties in dimension lumber, and gauge the suitability of nondestructive testing methods for potentially identifying high-value premium grades in solid-sawn softwood products.
40

ESTIMATING LEAKS IN WATER DISTRIBUTION SYSTEMS BY SEQUENTIAL STATISTICAL ANALYSIS OF CONTINUOUS FLOW READINGS

NADIMPALLI, GAYATRI January 2003 (has links)
No description available.

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