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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.
181

Correcting Errors Due to Species Correlations in the Marginal Probability Density Evolution

Tejeda, Abiezer 01 May 2013 (has links)
Synthetic biology is an emerging field that integrates and applies engineering design methods to biological systems. Its aim is to make biology an "engineerable" science. Over the years, biologists and engineers alike have abstracted biological systems into functional models that behave similarly to electric circuits, thus the creation of the subfield of genetic circuits. Mathematical models have been devised to simulate the behavior of genetic circuits in silico. Most models can be classified into deterministic and stochastic models. The work in this dissertation is for stochastic models. Although ordinary differential equation (ODE) models are generally amenable to simu- late genetic circuits, they wrongly assume that a system's chemical species vary continuously and deterministically, thus making erroneous predictions when applied to highly stochastic systems. Stochastic methods have been created to take into account the variability, un- predictability, and discrete nature of molecular populations. The most popular stochastic method is the stochastic simulation algorithm (SSA). These methods provide a single path of the overall pool of possible system's behavior. A common practice is to take several inde- pendent SSA simulations and take the average of the aggregate. This approach can perform iv well in low noise systems. However, it produces incorrect results when applied to networks that can take multiple modes or that are highly stochastic. Incremental SSA or iSSA is a set of algorithms that have been created to obtain ag- gregate information from multiple SSA runs. The marginal probability density evolution (MPDE) algorithm is a subset of iSSA which seeks to reveal the most likely "qualitative" behavior of a genetic circuit by providing a marginal probability function or statistical enve- lope for every species in the system, under the appropriate conditions. MPDE assumes that species are statistically independent given the rest of the system. This assumption is satisfied by some systems. However, most of the interesting biological systems, both synthetic and in nature, have correlated species forming conservation laws. Species correlation imposes con- straints in the system that are broken by MPDE. This work seeks to devise a mathematical method and algorithm to correct conservation constraints errors in MPDE. Furthermore, it aims to identify these constraints a priori and efficiently deliver a trustworthy result faithful to the true behavior of the system.
182

An Investigation of Methods for Estimating Marginal Values of Irrigation Water

Johnson, Richard L. 01 May 1967 (has links)
Marginal values of water us ed in irrigation are needed if water is to be optimally allocated among alternative uses. Cobb- Douglas production function analysis and linear programming methods were studied in this investigation to find their fruitfulness in predicting these marginal values. The theoretical properties of both methods indicate that they are conceptually capable of yielding valid marginal value estimates for irrigation water. Further investigation of the two methods was carried out as an empirical test in the Milford area of Utah . Marginal values of water used for irrigation in that area were estimated by both procedures. Although inviolable criteria for testing the validity of the estimates are not available, imperfect standards or' measure imply that they are sound. Linear programming and Cobb -Douglas production function anal ysis are therefore concluded to be fruitful methods of es timating marginal values of water used for irrigation.
183

FRINGE BENEFITS: RECLAIMING FORGOTTEN MARGINAL SPACE

SHULL, MATTHEW WILLIAM 14 July 2005 (has links)
No description available.
184

Impacto económico de la amonificación de forrajes de baja calidad en el sudoeste bonaerense

Piñeiro, Verónica Ana 09 December 2014 (has links)
El presente estudio evalúa el impacto económico que generaría la incorporación de forrajes de baja calidad amonificados en la alimentación de vacas de cría en el sudoeste de la provincia de Buenos Aires (SOB). El estudio alcanza a las 4 subregiones del SOB delimitadas por la Ley Provincial 13.647, a todo el SOB en general, y se podrá extrapolar a nivel productor particular. La incorporación de rollos de paja de trigo amonificados como único alimento de las vacas de cría en el último trimestre de gestación permite mantener un adecuado estado corporal a los vacas con el consecuente aumento de su porcentaje de preñez. Los beneficios incrementales que surgen del estudio de ingresos y costos de la asociación de la técnica resultan positivos para la mayor parte de la región bajo estudio. Se realiza un análisis de riesgo y simulación para determinar la sensibilidad de variables como el precio de los insumos y productos y el índice de preñez inicial. Los resultados de la investigación confirman parcialmente la hipótesis de que la práctica sea económicamente viable. Palabras clave: forrajes de baja calidad, amonificación, evaluación económica, análisis marginal, simulación / The present study evaluates the impact of the addition of ammoniated low quality forages in the feeding program of beef cows in the southwest Buenos Aires province (SOB). The present study includes the 4 subregions of the SOB defined by the Provincial Law 13.647, all of the SOB in general, and it could be extrapolated to the individual producer farm. The addition of amoniated wheat straw balls as the only food of breeding cows in the last trimester of pregnancy can maintain adequate body condition to cows with consequent increase in pregnancy rate. Incremental benefits from the study of incomes and costs of the association of the technique are positive for most of the region under study. Risk analysis and simulation is performed to determine the sensitivity of variables such as the price of inputs and outputs and the initial rate of pregnancy. The research results partially confirm the hypothesis that the practice is economically viable. Key words: low quality forages, ammoniation; economic evaluation, marginal analysis, simulation.
185

Personal Savings as a Function of Permanent Income

Lung, Robert Bruce 06 September 2002 (has links)
In this paper, a model to estimate personal savings is constructed using an estimate of permanent income. Traditional approaches to studying aggregate personal savings depend on many independent variables that serve as the determinants of personal saving. Because some of the determinants used in such approaches can be difficult to obtain, estimating aggregate saving in this manner can be time-consuming and arduous. Using an estimate of permanent income based on Friedman's Permanent Income Hypothesis (PIH), this paper creates a model to estimate personal savings and tests the model by examining the Marginal Propensity to Save (MPS) that is derived from it. Permanent income was estimated using a two-stage least squares (2SLS) method and aggregate personal savings is estimated using ordinary least squares (OLS). The empirical evidence reveals that savings estimates and marginal propensities to save are consistent with results obtained studies using conventional approaches except during periods in which a wealth effect occurs. During such periods, additional variables need to be added to the model to account for a wealth effect. This analysis therefore serves to further validate the PIH and shows that it can be applied to studying household savings as well as consumption. / Master of Arts
186

Urbanización marginal e impacto ambiental en la ciudad de Montería

Pinedo López, Jhon William 09 July 2012 (has links)
En esta tesis doctoral se analiza el impacto ambiental que tiene la urbanización marginal en una ciudad colombiana. Para ello, se aborda el estudio del fenómeno a partir de un enfoque multidisciplinar, que permite, por un lado, identificar las múltiples causas que estimulan este tipo de ocupación, y por el otro, presentar explicaciones lógicas acerca de su conformación, evolución, consolidación e impacto. El contexto geográfico de estudio es la ciudad de Montería; la investigación se realiza en ocho años, y el periodo analizado transcurre entre 1952 y 2010. La tesis muestra, a partir de diferentes enfoques disciplinares, el efecto negativo que la ocupación irregular causa a los subsistemas ecológico, social, económico y urbanístico, y los respectivos fenómenos que dicho efecto genera en cada uno de ellos, o colectivamente; es decir, la alteración de los ecosistemas locales, los riesgos sanitarios, la insalubridad, los desequilibrios económicos y las deficiencias urbanísticas que inciden negativamente en la calidad ambiental urbana de la ciudad de Montería. Además, se establecen diferentes categorías de asentamientos, asociadas esencialmente, a elementos de tipo constructivo, origen del dominio, tiempo de conformación y percepción de sus ocupantes. El enfoque multidisciplinar con que se aborda esta investigación exigió recurrir a una diversidad de elementos teóricos que provienen no sólo del urbanismo, sino de otras disciplinas como la arquitectura, la economía, la ecología, el derecho y la sociología, y dentro de los cuales destacamos los conceptos tradicionales de urbanización, o ciudad, �informal�, �marginal, �espontánea�, �irregular� �subnormal�, �asentamiento de desarrollo progresivo�, y �vivienda de autoconstrucción�. Igualmente se aportan nuevos elementos teóricos, que posibilitan una mejor comprensión y explicación del fenómeno, y la ampliación de un glosario, hasta ahora un tanto polémico. Estos conceptos son: �vivienda subnorma�, �vivienda de transición� .. / Pinedo López, JW. (2012). Urbanización marginal e impacto ambiental en la ciudad de Montería [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16468
187

[en] ELECTRICAL ENERGY PRICE STRUCTURING FOR THE BRAZILIAN MARKET / [pt] FORMAÇÃO DE PREÇOS DE ENERGIA ELÉTRICA PARA O MERCADO BRASILEIRO

CAROLINA FERREIRA SZCZERBACKI 27 September 2007 (has links)
[pt] Os preços de energia elétrica, insumo básico para todo o Modelo Setorial, constituem uma das maiores incertezas do setor. Estas incertezas abrangem todos os elementos formadores de preços: a oferta, a demanda e as regras de mercado, tornando muitas vezes difícil ao agente a avaliação concreta e precisa do processo da formação de preços e do impacto que a variação de um dos elementos do processo produz no resultado final. O objetivo deste trabalho é apresentar a estrutura de formação de preços no mercado energético brasileiro de forma sistematizada, avaliando a composição das variáveis que afetam esta estrutura: a demanda por consumo, a expansão do sistema e as disponibilidades energéticas. O mercado é modelado em todos os seus detalhes físicos, e o cálculo é realizado a partir de todo o arcabouço regulatório, incluindo a reprodução do modelo de operação ótima responsável pelos preços de energia. Descreve-se inicialmente um modelo de previsão de demanda por subsistema, utilizando-se técnicas de Teoria de Análise Funcional. Focaliza-se em seguida o suprimento futuro de energia no país a partir da expansão da oferta. Finalmente, utiliza-se uma simulação da operação ótima do sistema a partir da reprodução dos resultados do modelo utilizado no setor - o Newave - a partir de uma implementação própria desenvolvida especialmente no escopo deste trabalho. De posse dos possíveis cenários futuros, pode-se mensurar o impacto que a variação de cada elemento formador (demanda, expansão e afluências) tem sobre os custos de energia. É possível observar que as incertezas nestas variáveis podem gerar grandes impactos nos custos marginais e, conseqüentemente, nos custos futuros de energia elétrica. / [en] Energy Prices, essential input for the Sectorial Model, consist on the biggest uncertainties of the Electric Sector. These uncertainties enclose all price elements: the supply, the demand and the market rules, making sometimes difficult for the agents to evaluate the price process and the impact that the variation of each process element can produce on the result. The objective is to present Brazilian price process in a structuralized way, evaluating the variables composition that affects this structure: the demand, the electric system expansion and the energy supply availability. The market is modeled in all its physical details, and the calculation is done into the regulatory environment, including a reproduction of the optimal operation model responsible for energy prices. First, a demand forecast model is described, based on Functional Analysis Theory. Then, the focus is on the energy future supply, analyzing the supply expansion in Brazil. Finally, an optimal operation system is simulated, reproducing the sector model (Newave) results from an implementation developed in this work. From these possible future settings, each element (demand, expansion and energy supply availability) variation impact on energy prices can be measured. The simulations show that uncertainties about these variables can have big impacts on marginal costs and, consequently, on the energy future prices.
188

Avaliação da fusibilidade, desajuste marginal e união metalocerâmica do titânio comercialmente puro em função do tipo de revestimento e da temperatura final do molde / Evaluation of the castability, marginal misfit, and metal-ceramic bond strength of the commercially pure titanium in terms of investment type and mold final temperature

Macedo, Mônica Barbosa Leal 31 January 2008 (has links)
O propósito deste trabalho foi avaliar a fusibilidade, o desajuste marginal e a resistência de união metalocerâmica (RUMC) do titânio comercialmente puro (CP) em função do tipo de revestimento, Rematitan Plus (P) ou Rematitan Ultra (U), e da temperatura final do molde: 400°C (T1), 550°C (T2) ou 700°C (T3). A partir de uma matriz metálica com linha de término cervical em bisel de 30°, foram obtidos sessenta padrões de resina/cera em forma de coping para os ensaios de fusibilidade e desajuste marginal. Para o ensaio de RUMC, foram obtidos sessenta padrões de resina/cera em forma de cilindro, com 8 mm de comprimento e 5 mm de diâmetro, utilizando uma matriz de teflon. Os padrões foram incluídos em dois revestimentos para titânio (P e U), compreendendo um coping e um cilindro para cada um dos anéis, que foram submetidos a ciclos térmicos, com variação da temperatura final (T1, T2 e T3) e fundidos em titânio CP. Após resfriamento, as fundições foram desincluídas e jateadas com óxido de alumínio (100 &micro;m). Depois de recortados dos canais de alimentação, os copings foram submetidos aos ensaios de fusibilidade e desajuste marginal, enquanto os cilindros foram preparados para aplicação da cerâmica: suas superfícies foram usinadas, jateadas com óxido de alumínio (150 &micro;m) e limpas com jato de vapor. A fusibilidade foi expressa como a deficiência (&micro;m) entre a margem real da fundição e uma margem perfeita. As margens das amostras foram registradas em silicona e o raio (R) do arredondamento quantificado para o cálculo da deficiência em &micro;m (D), pela expressão D=2,7&middot;R. As medidas de desajuste marginal (&micro;m) foram feitas com os copings na matriz sob carga de 29,4 N. Na seqüência, os cilindros compostos pelo metal e disco cerâmico (5 mm de diâmetro de 2 mm de espessura) foram submetidos aos ensaios de RUMC por cisalhamento. Os dados obtidos foram analisados estatisticamente pelos testes ANOVA e Tukey (&alpha;=0,05). Os resultados mostraram que para fusibilidade do titânio CP, expressa em forma de deficiência marginal (&micro;m), houve diferença significante tanto para fatores, revestimentos (P<0,001, P=81±23 e U=64±11) e temperaturas (P<0,001, T1=69±9; T2=68±9 e T3=82±31), como para interação (P<0,001, PT1=66±7; PT2=69±10; PT3=109±18; UT1=71±11; UT2=67±8 e UT3=55±7). Para o desajuste marginal (&micro;m), também houve diferença significante para fatores, revestimentos (P<0,001, P=465±69 e U=69±58) e temperaturas (P=0,024, T1=220±190; T2=250±212 e T3=332±312), assim como para interação entre eles (P=0,032, PT1=369±150; PT2=436±118; PT3=590±233; UT1=70±63; UT2=64±63 e UT3=74±52). Porém, para RUMC (MPa) não houve diferenças significantes para os fatores revestimentos (P=0,062) e temperaturas (P=0,224), nem para interação entre eles (P=0,149). Concluiu-se que o revestimento U proporcionou melhor fusibilidade e menor desajuste marginal para o titânio CP do que P. T3 determinou pior fusibilidade e maior desajuste marginal do que T1. O efeito do aumento da temperatura final do molde na fusibilidade do titânio CP foi diferente para os revestimentos testados, produzindo melhores resultados para U e piores para P quando se passou de T2 para T3; porém, para o desajuste marginal, este efeito foi observado somente para P, determinando aumento do desajuste marginal quando se passou de T2 para T3. A RUMC não foi afetada pelos revestimentos testados, nem pelo aumento da temperatura do molde no momento da fundição do titânio CP. / The aim of this study was to evaluate the castability, marginal misfit, and metal-ceramic bond strength (MCBS) of the commercially pure (CP) titanium, in terms of investment type, Rematitan Plus (P) and Rematitan Ultra (U), and mold final temperature: 400°C (T1), 550°C (T2), and 700°C (T3). Sixty wax/acrylic resin crown patterns were prepared on a stainless steel stylized crown die having a 30-degree beveled finish line for castability and marginal misfit tests. Sixty wax/acrylic resin cylinder-shaped patterns (height of 8 mm and diameter of 5 mm) were prepared on a plastic matrix for MCBS test. The patterns were invested using two different investments for titanium (P and U). Each investing ring had two patterns: a crown and a cylinder. The casting rings were placed in a furnace to burn out patterns and thermally expand the molds, that were cooled at three temperatures (T1, T2, and T3) for casting in CP titanium. After the rings cooled, the castings were divested manually and airborne-particle abraded with 100-&micro;m aluminum oxide abrasive. Castings were then separated from their sprues. The cast crowns were performed for castability and marginal misfit tests. The cast cylinders were prepared for applying porcelain: their surfaces were machined, airborneparticle abraded with 150-&micro;m aluminum oxide abrasive and cleaned with steam spray. The castability was expressed in terms of the deficiency (&micro;m) between an actual casting margin and a perfect margin. Crown margins were recorded in a silicone impression material. The degree of marginal rounding (R) was measured and margin length deficiencies (&micro;m) (D) were calculated using the formula D=2.7&middot;R. The measurements of marginal misfit (&micro;m) of the cast crowns were performed on the stainlees steel die at a load of 29.4 N. The cylinders composed by metal and ceramic disk (height of 2 mm and diameter of 5 mm) were performed for test of metal-ceramic shear bond strength. Data were subjected to 2-way ANOVA and Tukey HSD test (&aplha;=.05). The results indicated for castability of CP titanium, expressed in terms of marginal deficiency (&micro;m), a significant difference for the main factors, investment (P<.001, P=81±23 and U=64±11), and temperature (P<.001, T1=69±9; T2=68±9; and T3=82±31), as well as for interaction (P<.001, PT1=66±7; PT2=69±10; PT3=109±18; UT1=71±11; UT2=67±8; and UT3=55±7). For marginal misfit (&micro;m), also there was significant difference for the main factors, investment (P<.001, P=465±69 and U=69±58) and temperature (P=.024, T1=220±190; T2=250±212; and T3=332±312), as well as for interaction (P=.032, PT1=369±150; PT2=436±118; PT3=590±233; UT1=70±63; UT2=64±63; and UT3=74±52). However, for MCBS (MPa) there were no significant differences for the main factors, investment (P=.062) and temperature (P=.224), as well as for interaction (P=.149). It was concluded that investment U provided better castability and lower marginal misfit for CP titanium than investment P. T3 provided worse castability and higher marginal misfit for CP titanium than T1. The effect of the increase in mold final temperature on the castability of CP titanium was different between investments, producing better results for U and worse results for P, from T2 to T3; for marginal misfit, this effect was only observed for P, provided higher marginal misfit from T2 to T3. The MCBS was similar between investments and there were no differences with the increase in the mold temperature for casting CP titanium.
189

Testes bayesianos para homogeneidade marginal em tabelas de contingência / Bayesian tests for marginal homogeneity in contingency tables

Carvalho, Helton Graziadei de 06 August 2015 (has links)
O problema de testar hipóteses sobre proporções marginais de uma tabela de contingência assume papel fundamental, por exemplo, na investigação da mudança de opinião e comportamento. Apesar disso, a maioria dos textos na literatura abordam procedimentos para populações independentes, como o teste de homogeneidade de proporções. Existem alguns trabalhos que exploram testes de hipóteses em caso de respostas dependentes como, por exemplo, o teste de McNemar para tabelas 2 x 2. A extensão desse teste para tabelas k x k, denominado teste de homogeneidade marginal, usualmente requer, sob a abordagem clássica, a utilização de aproximações assintóticas. Contudo, quando o tamanho amostral é pequeno ou os dados esparsos, tais métodos podem eventualmente produzir resultados imprecisos. Neste trabalho, revisamos medidas de evidência clássicas e bayesianas comumente empregadas para comparar duas proporções marginais. Além disso, desenvolvemos o Full Bayesian Significance Test (FBST) para testar a homogeneidade marginal em tabelas de contingência bidimensionais e multidimensionais. O FBST é baseado em uma medida de evidência, denominada e-valor, que não depende de resultados assintóticos, não viola o princípio da verossimilhança e respeita a várias propriedades lógicas esperadas para testes de hipóteses. Consequentemente, a abordagem ao problema de teste de homogeneidade marginal pelo FBST soluciona diversas limitações geralmente enfrentadas por outros procedimentos. / Tests of hypotheses for marginal proportions in contingency tables play a fundamental role, for instance, in the investigation of behaviour (or opinion) change. However, most texts in the literature are concerned with tests that assume independent populations (e.g: homogeneity tests). There are some works that explore hypotheses tests for dependent proportions such as the McNemar Test for 2 x 2 contingency tables. The generalization of McNemar test for k x k contingency tables, called marginal homogeneity test, usually requires asymptotic approximations. Nevertheless, for small sample sizes or sparse tables, such methods may occasionally produce imprecise results. In this work, we review some classical and Bayesian measures of evidence commonly applied to compare two marginal proportions. We propose the Full Bayesian Significance Test (FBST) to investigate marginal homogeneity in two-way and multidimensional contingency tables. The FBST is based on a measure of evidence, called e-value, which does not depend on asymptotic results, does not violate the likelihood principle and satisfies logical properties that are expected from hypothesis testing. Consequently, the FBST approach to test marginal homogeneity overcomes several limitations usually met by other procedures.
190

Um estudo sobre os saraus da periferia de São Paulo: espaços para \"aprender na amizade e na liberdade\" / A study of the saraus of the outskirts of São Paulo: spaces to \"learn in friendship and in freedom

Chamone, Aline Maria Macedo 20 October 2016 (has links)
Este trabalho buscou estabelecer relações possíveis entre a literatura e a formação, para isso, se debruçou em um estudo sobre os saraus da periferia de São Paulo. O tema da literatura marginal/periférica é trazido juntamente à noção da literatura como possibilidade de formação, ação social, sociabilidade e resistência. Autores como Candido e Larrosa auxiliaram na compreensão formativa da literatura e seu caráter humanizador. Martuccelli aparece como perspectiva teórica para o entendimento dos indivíduos latino-americanos, suas especificidades e relações com o movimento de literatura marginal/periférica. É apresentada uma discussão sobre a literatura marginal/periférica no cenário atual, bem como, um mapeamento dos saraus que acontecem na periferia da cidade. Foram realizadas entrevistas com escritores e escritoras desse movimento para entender suas trajetórias de formação por meio da literatura assim como o encontro com os saraus. Por fim, traz o sarau como um espaço formativo no qual é possível aprender na amizade e na liberdade. / This study aimed to establish possible links between literature and training, to this end, it leaned on the study of the saraus of the outskirts of São Paulo. The theme of marginal/peripheral literature is brought together with notion of literature as a possible training, social action, sociability and resistance. Authors like Candido and Larrosa assisted in the formative understanding of literature and its humanizing character. Martuccelli appears as a theoretical perspective for the understanding of Latin American individuals, their characteristics and relations with the movement of marginal/peripheral literature. A discussion of the marginal/peripheral literature is presented in the current scenario, as well as a mapping of saraus that take place on the outskirts of the city. Interviews with writers of this movement were conducted to understand their learning paths through literature as well as the meeting with the saraus. Finally, bringing the saraus as a formative space in which to learn in friendship and in freedom.

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