In a generalized linear mixed model (GLMM), the random effects are typically uncorrelated and assumed to follow a normal distribution. However, findings from recent studies on how the misspecification of the random effects distribution affects the estimated model parameters are inconclusive. In the thesis, we extend the randomization approach for deriving linear models to the GLMM framework. Based on this approach, we develop an algorithm for estimating the model parameters of the randomization-based GLMM (RBGLMM) for the completely randomized design (CRD) which does not require normally distributed random effects. Instead, the discrete uniform distribution on the symmetric group of permutations is used for the random effects. Our simulation results suggest that the randomization-based algorithm may be an alternative when the assumption of normality is violated. In the second part of the thesis, we consider an RB-GLMM for the randomized complete block design (RCBD) with random block effects. We investigate the effect of misspecification of the correlation structure and of the random effects distribution via simulation studies. In the simulation, we use the variance covariance matrices derived from the randomization approach. The misspecified model with uncorrelated random effects is fitted to data generated from the model with correlated random effects. We also fit the model with normally distributed random effects to data simulated from models with different random effects distributions. The simulation results show that misspecification of both the correlation structure and of the random effects distribution has hardly any effect on the estimates of the fixed effects parameters. However, the estimated variance components are frequently severely biased and standard errors of these estimates are substantially higher.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2016-09-14T18:15:51Z No. of bitstreams: 1 Maria Eliana Santana Da Cruz Silva.pdf: 2630796 bytes, checksum: 59dcb18293cd1765db482b9ff7efb016 (MD5) / Made available in DSpace on 2016-09-14T18:15:51Z (GMT). No. of bitstreams: 1 Maria Eliana Santana Da Cruz Silva.pdf: 2630796 bytes, checksum: 59dcb18293cd1765db482b9ff7efb016 (MD5) Previous issue date: 2016-03-21 / This doctoral dissertation reports an investigation of the conceptions of linear transformation held by teaching certification students in mathematics following a course of linear algebra devised to involve students in the search for elements to build the concept of this mathematical object. The analysis of these conceptions was carried out according to the APOS theory by Dubinsky and Lewin (1986) and Asiala et al. (1996), in articulation with premises of didactic engineering (MACHADO, 2010). The investigation was a qualitative, case-study type, which, according to Bogdan and Biklen (1994) and Lüdke and André (1986), enables the context studied to be investigated and interpreted, given that all qualitative studies seek to portray reality in a more dense fashion and represent the different perspectives present in a given social situation. Centered on this understanding of qualitative research, classes were organized with the aim of actively involving the study participants to facilitate data collection, which was carried out three semesters after the linear algebra course. Premises of didactic engineering were employed to prepare and conduct the activities, which were discussed and solved by paired students. Their interactions were audio recorded and also noted by an observer. The analysis revealed that the subjects paired for the activities experienced different stages in terms of conception (action, process, and object) in most of the activities. We concluded that the students investigated did not always show a conception of object during the activities, but were all able to demonstrate a conception of process for the notion of linear transformation / Esta tese apresenta uma pesquisa que busca investigar as concepções de transformação linear de alunos de uma licenciatura em matemática ao vivenciarem um curso de álgebra linear elaborado com a intenção de envolvê-los na busca de elementos para a construção desse objeto matemático. A análise das concepções se embasou principalmente em partes da teoria APOS, de Dubinsky e Lewin (1986) e Asiala et al. (1996), articulada com alguns pressupostos da engenharia didática (MACHADO, 2010). A pesquisa se caracteriza como qualitativa, abordagem que, segundo Bogdan e Biklen (1994) e Lüdke e André (1986), possibilita investigar e interpretar o contexto investigado, uma vez que todo estudo qualitativo visa retratar a realidade de forma densa, procurando representar as diferentes perspectivas presentes em dada situação social. A partir dessa compreensão de pesquisa qualitativa, foi possível organizar aulas com o objetivo de envolver ativamente os participantes da pesquisa, de forma a facilitar a coleta de dados, que foi realizada após três semestres do curso em questão. Utilizamos pressupostos da engenharia didática na preparação e execução das atividades, discutidas e resolvidas em duplas, atividades essas audiogravadas e descritas por um observador. As análises revelaram que os sujeitos que compuseram as duplas durante a realização das atividades vivenciaram diferentes etapas em termos de concepção (ação, processo e objeto) na maioria das atividades propostas. Concluímos que os sujeitos da pesquisa nem sempre demonstraram uma concepção de objeto no desenvolvimento das atividades, mas todos foram capazes de demonstrar uma concepção de processo da noção de transformação linear

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Vita. / Bibliography: leaves 307-312. / by Peter Parr Mongeau. / Ph.D.

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Este trabalho visa obter um plano de corte economicamente ótimo para florestas de eucaliptos. A técnica utilizada é a programação linear. O objetivo do modelo desenvolvido é a maximização do retorno sobre os investimentos. Para tanto, foram calculados o Valor Líquido Presente (VLP) de todas as alternativas de manejo dadas ao modelo, neste cálculo foi considerado como parte integrante do fluxo de caixa o Valor Esperado da Terra (VET). Na determinação do plano de manejo mais adequado, foram analisados quatro diferentes cenários de planejamento dos pontos de vista econômico e operacional. Os quatro cenários foram: 1) oscilação livre da produção anual; 2) suprimento anual de madeira para celulose superior ao limite de 40.000 m3/ano; 3) suprimento anual de madeira para celulose inferior ao limite máximo de 100.000 m3/ano; 4) suprimento anual de madeira para celulose restrito a intervalos. Os resultados demonstraram que, independente da estratégia de manejo obtida, dentro das condições etipuladas, a produção florestal não é deficitária. A estratégia de manejo de corte considerada mais apropriada foi a do cenário cujo fluxo de produção ficou restrito a intervalos / The purpose of this paper was to obtain, an optimal economic planning for management and logging of Eucalypt forests. The technique utilized is linear programming. The objective of the modelo was to maximize the return over the investiments. Therefor the Net Present Value (NPV) of all management alternative conditions given to were calculated the model. In this computation the Bare Land Value (BLV) was considered part of the cash flow. For determination of the most suitable management planning to the mill supply, four different scenarios of economical and operational planning were analised. The scenarios were: 1) free oscillation to the anual productions of wood; 2) Annuak wood supply for pulpwood above minimum limit (40.000 m3/year); 3) annual wood supply for pulpwood below the maximum limit the 100.000 m3/year; 4) annual woos supply for pulpwood restricted to pre-fixed intervals. The results showed that, independent of management strategy obtained under the considered adjusted conditions, the forest production was not deficient. The best management alternative, considering the technological and operational limitations, was that from the scenary in which the production flow was restricted to pre-fixed intervals

Dissertação (Mestrado em Engenharia Mecânica) - Centro Universitário da FEI, São Bernardo do Campo, 2015

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Tese de mestrado. Métodos Computacionais em Ciências e Engenharia. 2004. Faculdade de Engenharia. Universidade do Porto

Dissertation submitted to the Faculty of the Graduate School of the University of Maryland in partial fulfillment of the requirements for the degree of Doctor of Philosophy