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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.
431

Statistical analysis of a high accuracy pointing and tracking system

Pfeiffer, George Ward January 1975 (has links)
Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / Bibliography: leaf 112. / by George W. Pfeiffer. / M.S.
432

Estimation and variational methods for gradient algorithm generation.

Toldalagi, Paul Michel January 1977 (has links)
Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 110-113. / M.S.
433

Multivariable feedback design by shaping singular values

Pagezy, Christophe Jacques January 1982 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Christophe Jacques Pagezy. / M.S.
434

Panorama do setor energético e seu relacionamento com o agronegócio brasileiro: um estudo com uso de técnicas multivariadas / Overview of the energy sector and its relationship with the Brazilian agribusiness: a study with use of multivariate techniques

Gonsales Neto, Rafael 15 August 2016 (has links)
O complexo agroindustrial (CAI), como relação comercial e industrial envolvendo a cadeia produtiva de produtos de origem vegetal e animal, percebe que o insumo \"energia\" tem se tornado cada dia mais importante, ocupando lugar de destaque na avaliação de custos de produção. Neste contexto, o panorama do setor energético indica uma influência imediata na produção de riquezas advindas deste setor e seus setores correlatos. O CAI é hoje delimitado pelos seguintes segmentos: o das indústrias que fornecem para o setor agropecuário, as quais se entendem como as indústrias de bens de capital, defensivos, fertilizantes, sementes e matrizes, assim como de outros insumos; o do setor agropecuário em si; o das indústrias que fazem uso das matérias-primas do setor agropecuário, do qual se distinguem a agroindústria e a indústria de alimentos; e o do comércio e serviços de produtos agropecuários. Este trabalho apresenta um estudo utilizando técnicas multivariadas que relacionam os segmentos do CAI, suas demandas e consumos de energia, os indivíduos produtores e consumidores, os quais são aqui representados pelas unidades federativas (UF), e suas capacidades em produzir riquezas para o país, ou seja, suas respectivas contribuições ao produto interno bruto (PIB). A análise continua pelos energéticos envolvidos e por suas evoluções na produção e consumo, concluindo com as definições das correlações que apresentam uma visão sistêmica de como o panorama energético do país pode influenciar na cadeia do agronegócio, para dentro e fora da porteira das fazendas. / The agroindustrial complex (CAI), as industrial and commercial relationship involving the production chain of products of plant and animal origin, realizes that the input \"energy\" has become increasingly important, occupying a prominent place in the evaluation of production costs. In this context, the overview of the energy sector indicates an immediate influence on the production of wealth arising from this sector and its related industries. The CAI is now defined by the following segments: the industries that provide for the agricultural sector, which are understood as the industries of capital goods, pesticides, fertilizers, seeds and dies, as well as other inputs; the agricultural sector itself; the industries that make use of raw materials in the agricultural sector, which are distinguished agribusiness and the food industry; and the trade of agricultural products and services. This paper presents a study using multivariate techniques relating segments of the CAI, their demands and energy consumption, producers and consumers individuals, which are represented here by the federal units (UF), and its capacity to produce wealth for the country, ie their contribution to gross domestic product (GDP). The analysis continues by energy involved and their developments in production and consumption, concluding with the definitions of correlations that have a systemic view of how the energy landscape of the country can influence the agribusiness chain, inside and outside the gate of the farm.
435

Significado do trabalho: estudo nos setores público e privado / Meaning of working: a study in the public and private sectors

Kubo, Sergio Hideo 21 October 2009 (has links)
O trabalho tem sido visto não somente como forma de obter a renda, mas como atividade que proporciona realização pessoal, status social e a possibilidade de estabelecer e manter contatos interpessoais, entre outros. Essa pesquisa teve como objetivo investigar os fatores que influenciam e conferem sentido ao trabalho, tais como: - centralidade do trabalho, onde se procurou investigar o grau de importância do trabalho dentro do contexto das diversas áreas da vida das pessoas tais como família, lazer, religião e vida comunitária; - normas da sociedade tanto como fornecedora de condições como cobradora de atitudes; - objetivos e resultados valorizados, refletindo o que se busca com o trabalho. Adicionalmente, verificaram-se os diferentes significados do trabalho em função das características dos respondentes, em especial considerando os trabalhadores do setor público e de outros setores. A partir da pesquisa na literatura, foi elaborado um modelo inicial que, não se mostrando satisfatório à luz da amostra colhida, foi substituído por um outro, entre quatro analisados. O modelo escolhido foi o que melhor goodness of fit apresentou, utilizando-se modelagem de equações estruturais pelo método partial least square. Identificou-se, entre outros resultados, que o significado do trabalho se reflete, na ordem, na centralidade do trabalho, objetivos e resultados valorizados e por último, nas normas sociais. Analisando-se as diferenças entre a sub-amostra do setor público e a de outros setores, concluiu-se que os respondentes do setor público vêem o trabalho também como sentido da vida, valorizam que a tarefa seja adequada à capacidade e que tenha variedade. Os respondentes de outros setores, por sua vez, valorizam um bom ambiente físico, um bom relacionamento interpessoal, o trabalho interessante e um bom salário. Para complementar a pesquisa, foram utilizadas outras técnicas de análises, tais como regressão logística, comparação de médias e análise fatorial exploratória. Quanto à centralidade no trabalho, apresentaram maiores valores: as mulheres, os solteiros e os de maior escolaridade. Se for considerada a influência das normas sociais orientadas a deveres, apresentaram maiores valores: as mulheres, os solteiros, os religiosos, os com menos dependentes e os mais satisfeitos com a vida. Quanto ao índice de significado do trabalho, as mulheres se destacaram, apresentando maiores valores. / Work has been seen not only as a means of obtaining income, but as an activity that promotes personal achievement, social status and the possibility of establishing and maintaining interpersonal contacts, among other factors. This research aimed to investigate the factors that influence and give meaning to work such as: - work centrality, which aimed to investigate the degree of the importance of work within the context of different areas of people\'s lives, such as family, leisure, religion and life in community; - social norms, both as a supplier of conditions such as a collector of attitudes; - valued objectives and results, reflecting what one aspires to by working. Additionally it sought to identify different meanings depending on the respondents´ characteristics, especially considering workers from public and other sectors. Based in the literature, an initial model was developed, which did not prove satisfactory in light of the sample. The initial model was then replaced by another, from among four models examined. The chosen model presented the best goodnessof- fit under the structural equation modeling using partial least square method. It was found, among other results, that the meaning of work reflects, by order, on the centrality of work, on valued objectives and results and finally, on social norms. Analyzing the differences between the public sector´s sub-sample and that of other sectors, it was concluded that the respondents in the public sector see work as a meaning for life, value the appropriateness of the tasks to their capacity and the variety of tasks. The respondents of other sectors, in turn, place a higher value on a proper working environment, good interpersonal relationships, the attractiveness of tasks and good remuneration. To complement the research, other techniques were used, such as logistic regression, comparison of means and exploratory factor analysis. With regard to work centrality, women have higher values than men, as do singles and those with higher education. If considering the influence of duty-oriented social norms, higher values were found for: women, singles, religious individuals, those with less dependents and those more satisfied with life. For the meaning of work, women stood out by showing higher values.
436

Application of Distance Covariance to Extremes and Time Series and Inference for Linear Preferential Attachment Networks

Wan, Phyllis January 2018 (has links)
This thesis covers four topics: i) Measuring dependence in time series through distance covariance; ii) Testing goodness-of-fit of time series models; iii) Threshold selection for multivariate heavy-tailed data; and iv) Inference for linear preferential attachment networks. Topic i) studies a dependence measure based on characteristic functions, called distance covariance, in time series settings. Distance covariance recently gathered popularity for its ability to detect nonlinear dependence. In particular, we characterize a general family of such dependence measures and use them to measure lagged serial and cross dependence in stationary time series. Assuming strong mixing, we establish the relevant asymptotic theory for the sample auto- and cross- distance correlation functions. Topic ii) proposes a goodness-of-fit test for general classes of time series model by applying the auto-distance covariance function (ADCV) to the fitted residuals. Under the correct model assumption, the limit distribution for the ADCV of the residuals differs from that of an i.i.d. sequence by a correction term. This adjustment has essentially the same form regardless of the model specification. Topic iii) considers data in the multivariate regular varying setting where the radial part $R$ is asymptotically independent of the angular part $\Theta$ as $R$ goes to infinity. The goal is to estimate the limiting distribution of $\Theta$ given $R\to\infty$, which characterizes the tail dependence of the data. A typical strategy is to look at the angular components of the data for which the radial parts exceed some threshold. We propose an algorithm to select the threshold based on distance covariance statistics and a subsampling scheme. Topic iv) investigates inference questions related to the linear preferential attachment model for network data. Preferential attachment is an appealing mechanism based on the intuition “the rich get richer” and produces the well-observed power-law behavior in net- works. We provide methods for fitting such a model under two data scenarios, when the network formation is given, and when only a single-time snapshot of the network is observed.
437

Análise multivariada no mapeamento genético de traços quantitativos / Multivariate analysis in genetic mapping of quantitative traits

Esteban Duarte, Nubia 18 June 2007 (has links)
Em pesquisa Genômica é de grande interesse o mapeamento de genes que controlam traços ou fenótipos quantitativos. Metodologias estatsticas para identicar genes que tenham efeitos sobre um unico traço são bem conhecidas na literatura e têm sido exaustivamente aplicadas no mapeamento genético de muitas doenças. Porem, na pratica, diferentes traços são correlacionados, como é o caso de hipertensão e obesidade, possivelmente, devido a aço de genes comuns envolvidos na sua regulação. Nestes casos, por meio de tecnicas estatísticas multivariadas, que exploram a estrutura de covariância entre os traços, é possvel identificar genes não detectados por analises univariadas, ganhar precisão nas estimativas dos efeitos e conhecer a posicão desses genes, alem de testar efeitos de pleiotropia (um mesmo gene controlando varios traços) e interacções gene-ambiente (os genes que controlam a pressão antes e depois de dieta com sal). Neste trabalho diferentes alternativas de analise estatstica são consideradas para explorar a informacão de vários tracos conjuntamente: modelo de regressão intervalar multivariado (Jiang & Zeng, 1995), mapeamento multivariado via a teoria espectral (Mangin et al.,1998), via medidas resumo relevantes (como a diferenca entre respostas antes e depois de uma exposição) e via ajustes por covariaveis. Também são introduzidas algumas abordagens graficas para o estudo do efeito de pleiotropia e interação geneambiente. As metodologias supracitadas são aplicadas a dados reais fornecidos pelo Laboratorio de Cardiologia e Genética Molecular do InCor/USP, que consideram várias medidas de pressão arterial em ratos provenientes de uma população F2. / In Genomic research, the mapping of genes which control quantitative traits has been of great interest. Statistical methods for detection of genes, in uencing a single trait, are well known in the literature and they have been exhaustive used in the genetic mapping of many diseases. However, in real situations, dierent kind of traits are correlated, such as hypertention and obesity, that would be due to the action of a set of commom genes involved in the regulation of these traits. In these cases, through of multivariate statistical techniques, which explore the covariance structure between the traits, it is possible to identify genes that are not detected by univariated analysis. In addition multivariate analysis are useful to obtain accurate estimates and to know the position of these genes, besides testing eects of pleiotropic (a gene controlling several traits) and geneenvironmental interations (genes that control the pressure before and after salt diet). In this work dierent alternatives from statistical analysis are considered to explore information of several traits jointly: Interval multivariate regression models (Jiang and Zeng, 1995); multivariate mapping through the espectral theory (Mangin et al. 1998), summary measures (for example, models formulated in terms of the dierence between two traits) and adjustments including covariates. Also, graphics procedures are introduced in order to study eects of pleiotropy and geneenvironmental interactions . The methodologies mentioned above are applied to real data set, supplied by the Cardiology and Molecular Genetic Laboratory of Heart institute (InCor-USP), that consider several measurements of blood pressure in rats that come from a F2 population.
438

O uso de técnicas estatísticas multivariadas em dissertações e teses sobre o comportamento do consumidor: um estudo exploratório / The use of the statistics technique of multivariate analysis in dissertations and theses related to consumer behavior: a exploratory study

Prearo, Leandro Campi 29 August 2008 (has links)
A presente dissertação teve como principal objetivo avaliar o nível de adequação das técnicas estatísticas de análise multivariada em dissertações e teses da área de Marketing, na temática do comportamento consumidor, entre 1997 e 2006, apresentadas aos Programas de Pós Graduação da Faculdade de Economia, Administração e Contabilidade da Universidade de São Paulo e da Escola de Administração de Universidade Federal do Rio Grande do Sul. Para atender a esse objetivo, buscou-se organizar um referencial teórico que subsidiasse a discussão sobre os objetivos de aplicação de cada uma das técnicas, bem como que subsidiasse a construção de um procedimento de avaliação a partir do atendimento a premissas subjacentes ao uso dessas técnicas. Foram analisados cinqüenta e seis estudos com aplicação das técnicas multivariadas, dentre os cento e noventa seis estudos disponíveis sobre a temática em referência no período. Desse universo, delimitou-se o público-alvo em noventa e nove aplicações dessas técnicas. A adequação da aplicação das técnicas às necessidades dos problemas de pesquisa foi verificada em 100% dos casos. Entretanto, quanto ao atendimento às premissas, o resultado foi negativo: apenas 16,8% das aplicações mostraram-se adequadas, atendendo a todas as premissas exigidas. A técnicas de Análise Fatorial Exploratória foi a mais utilizada no período, seguida da Modelagem de Equações Estruturais e da Análise de Regressão. As premissas mais verificadas foram a de sensibilidade ao tamanho da amostra e a de padronização dos dados; as menos verificadas foram as premissas de normalidade multivariada, linearidade, homoscedasticidade e autocorrelação dos resíduos. De forma geral, os resultados sugerem a necessidade de um aumento do comprometimento dos pesquisadores na verificação de todos os preceitos teóricos de aplicação de cada técnica. / This dissertation has the purpose to evaluate the level of adaptation of the statistics technique of multivariate analysis in dissertations and theses related to Marketing, consumer behavior, during 1997 and 2006, introduced at Programs of Masters degree of the Faculdade de Economia, Administração e Contabilidade da Universidade de São Paulo and of the Escola de Administração da Universidade Federal do Rio Grande do Sul. To reach this purpose, was organized a theoretical referential that would subsidize the discussion about the objectives of each technique application, and one that would subsidize the construction of an evaluation procedure starting with the attention to the subjacent premises to the use of these techniques. It was analyzed fifty-six studies of a hundred-ninety-six available on the thematic on the period, which used multivariate application techniques. Based on a consumer target, was delimited ninety-nine applications of that technique. The application of the techniques was observed at 100% of the cases where they were suited to the necessities of the research problems. However, taking the premise attention the results were negative: only 16.8% of the applications were suited, following all the premises required. The technique Factorial Exploration Analysis was the most used technique on the period, followed by Structures Equations Modeling and Regression Analysis. The most verified premises were the sensibility to the size of the sample and the data standardization; the least verified were multivariate normality, linearity, homoscedasticity, and autocorrelation. The results suggest the necessity of a higher commitment of the researchers on the verification of all theoretical precept of each technique application.
439

Building reliable credit rating system for firms in China.

January 2005 (has links)
Bai Ling. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 77-80). / Abstracts in English and Chinese. / INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Research Approach and Design --- p.4 / Chapter 1.3 --- Organization of the Thesis --- p.5 / LITERATURE REVIEW ON CREDIT RISK MODELING --- p.6 / Chapter 2.1 --- Overview --- p.6 / Chapter 2.2 --- Discriminant Analysis --- p.8 / Chapter 2.3 --- Logit Regression --- p.10 / Chapter 2.4 --- Regression and Classification Tree (CART) --- p.10 / Chapter 2.3 --- Chapter Summary --- p.12 / FALSE FINANCIAL STATEMENTS DETECTION --- p.13 / Chapter 3.1 --- Overview --- p.13 / Chapter 3.2 --- Empirical Studies on Financial Scandal and False Financial Statements (FFS) --- p.14 / Chapter 3.3 --- False Financial Statements (FFS) Detection --- p.17 / Chapter 3.4 --- Chapter Summary --- p.23 / RESEARCH METHODOLOGIES IN CREDIT SCORING & FALSE FINANCIAL STATEMENTS DETECTION --- p.25 / Chapter 4.1 --- Overview --- p.25 / Chapter 4.2 --- Logit Regression --- p.26 / Chapter 4.3 --- Classification and Regression Tree (CART) --- p.31 / Chapter 4.4 --- Chapter Summary --- p.34 / PROPOSED STUDY FRAMEWORK --- p.35 / Chapter 5.1 --- The COMPLETE Framework --- p.35 / Chapter 5.2 --- Rating Process --- p.43 / Chapter 5.3 --- Chapter Summary --- p.45 / DEVELOPING THE CREDIT SCORING MODEL --- p.46 / Chapter 6.1 --- Overview --- p.46 / Chapter 6.2 --- Sample --- p.46 / Chapter 6.3 --- Variables --- p.47 / Chapter 6.4 --- Result of the Univariate Analysis --- p.49 / Chapter 6.5 --- Develop the Bankruptcy Risk Model with Logit Regression --- p.50 / Chapter 6.6 --- Chapter Summary --- p.54 / INVESTIGATING FALSE FINANCIAL STATEMENTS --- p.55 / Chapter 7.1 --- Overview --- p.55 / Chapter 7.2 --- Impact of False Financial Statements (FFS) on Credit Risk Assessments - Evidence from Lantian's Case --- p.55 / Chapter 7.3 --- Evaluating the Trustworthiness Aspect for Lantian --- p.56 / Chapter 7.4 --- Analyze FFS with Statistical Tools --- p.59 / Chapter 7.5 --- Chapter Summary --- p.73 / SUMMARY --- p.75 / REFERENCES --- p.77
440

Características anatômicas foliares e controle químico em pós-emergência de Brachiaria decumbens e Brachiaria plantaginea

Marques, Renata Pereira [UNESP] 13 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-13Bitstream added on 2014-06-13T20:48:37Z : No. of bitstreams: 1 marques_rp_me_botfca.pdf: 737244 bytes, checksum: 34ea11b2b5ef3ad998b96669ba44d3d7 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / objetivo do presente trabalho foi relacionar as características anatômicas foliares de Brachiaria decumbens Stapf (capim-braquiária) e Brachiaria plantaginea (Link) Hitchc. (capim-marmelada), com a eficiência do controle químico em pósemergência por meio de herbicidas inibidores da enzima ACCase, visando fornecer subsídios para o manejo químico dessas espécies daninhas. A semeadura de B. decumbens e B. plantaginea foi feita em vasos plásticos contendo solo e mantidos em casa de vegetação. Para se proceder à análise anatômica foliar, foi amostrada a porção mediana do limbo da terceira folha expandida, contada a partir da base do colmo, compreendendo três estádios de desenvolvimento da planta: Estádio 1 (plantas com 4-6 folhas aos 15 dias após a emergência), Estádio 2 (plantas com 3-4 perfilhos aos 23 dias após a emergência), Estádio 3 (plantas adultas no início do florescimento aos 48 dias após a emergência). Avaliaram-se as estruturas anatômicas das regiões da quilha (nervura central) e da asa (porção compreendida entre a nervura central e a margem do limbo), utilizando-se de mesa digitalizadora com programa computacional específico. Os caracteres anatômicos foliares quantitativos analisados, nos três estádios de desenvolvimento, foram: área da seção transversal; porcentagens de epiderme das faces adaxial e abaxial, esclerênquima, endoderme (bainha do feixe vascular), feixe vascular e parênquima; espessura da folha; distância entre os feixes vasculares; comprimento do estômato; número de estômatos e de tricomas (curtos e longos). Os valores desses caracteres foram submetidos aos testes estatísticos multivariados de Análise de Agrupamento e Análise de Componentes Principais. Para a avaliação do controle químico foram testados os herbicidas fluazifop-p-butil na dose... / The aim of this study was to correlate the leaf anatomical characteristics of Brachiaria decumbens Stapf (signal grass) and Brachiaria plantaginea (Link) Hitchc. (Alexandergrass) with the chemical control efficacy in post-emergence through ACCase-inhibitor enzyme herbicide application in order to contribute to the chemical management of those weed species. B. decumbens and B. plantaginea were sown in plastic pots filled with soil and kept in a greenhouse. For leaf anatomical analysis, the blade median portion of the third expanded leaf, counted from the stem basis, was sampled. Plants were divided into three developmental phases: Stage 1 (plants presenting 4-6 leaves at 15 days after emergence), Stage 2 (plants presenting 3-4 tillers at 23 days after emergence), and Stage 3 (adult plants in the beginning of flowering at 48 days after emergence). Anatomical structures of keel (midrib) and wing (a portion between the midrib and the blade margin) were evaluated by using a digitizer tablet including specific software. Leaf quantitative anatomical characters analyzed in the three development stages were: transversal section area; percentages of epidermal cells in adaxial and abaxial surfaces, sclerenchyma, endodermis (vascular bundle sheath), vascular bundle, and parenchyma; leaf thickness; distance among vascular bundles; stomatal length; number of stomata and trichomes (short and long). The values of these characters were subjected to multivariate statistical tests through Cluster Analysis and Principal Component Analysis. For chemical control evaluation, the following herbicides were tested: fluazifop-p-butyl 150 g ha-1, haloxyfop-methyl 50 g ha-1 and sethoxydim 230 g ha-1. Post-emergence applications were performed in all three plant development stages, and visual evaluations were... (Complete abstract click electronic access below)

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