• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 34
  • 33
  • 9
  • 9
  • 7
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 115
  • 21
  • 16
  • 13
  • 12
  • 12
  • 11
  • 11
  • 11
  • 11
  • 10
  • 10
  • 9
  • 9
  • 9
  • 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.
41

Ensaios sobre fun????o de produ????o e e ci??ncia: uma abordagem baseada em vine-c??pulas

Oliveira, Michel Angelo Constantino de 28 November 2014 (has links)
Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-10-30T13:13:38Z No. of bitstreams: 1 MichelAngeloConstantinodeOliveiraTese2014.pdf: 517065 bytes, checksum: a528b5761c52e0544f3e4b39cddabf3f (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-10-30T13:15:02Z (GMT) No. of bitstreams: 1 MichelAngeloConstantinodeOliveiraTese2014.pdf: 517065 bytes, checksum: a528b5761c52e0544f3e4b39cddabf3f (MD5) / Made available in DSpace on 2017-10-30T13:15:02Z (GMT). No. of bitstreams: 1 MichelAngeloConstantinodeOliveiraTese2014.pdf: 517065 bytes, checksum: a528b5761c52e0544f3e4b39cddabf3f (MD5) Previous issue date: 2014-11-28 / UCB / Economic theory uses the production function to develop microeconomic and macroeconomic analyses, respectively at the level of rm and wealth of nations. This thesis proposes a new model for application in the production function, introducing instrumental copulas for modelling the dependence structure of random variables for analysis of asymmetric behavior and extreme events. In the rst test the function of traditional production is modeled using vine-copula for rms from the USA, Germany and England, so it was possible to construct multivariate distributions and estimation of capital-output pairs (y ???? k) variables; work-product (y ???? l); working-capital as a production (k ???? ljy); and know the structures associated dependencies, evaluating the nonlinear dependence and heavy tails. For the second test, following the data and methodological procedures of the rst test, using vine-copula and the construction parameters and coe cient of dependence are the same. The di erence is in the modelling of stochastic frontier and approach insu ciency using this new type of instrument. The marginal distributions were estimated using the gamma function and normal function, several families of copulas were found, including Gumbel, Student-t, BB7, Normal and Clayton which implies changes in behavior and dependence of each pair of variables over the years and in each country, in addition to showing the heavy tails where rms of large and / or small focus. This change in families con rm the stochastic behavior of the data and the production function, in contrast to the inappropriate use of deterministic functions and multivariate normality assumption. / A teoria econ??mica utiliza a fun????o de produ????o para desenvolver an??lises microecon??micas e macroecon??micas, respectivamente ao n??vel da rma e riqueza das na????es. Este trabalho de tese prop??e uma nova modelagem para aplica????o em fun????o de produ????o, introduzindo o instrumental de c??pulas para modelagem da estrutura de depend??ncia em vari??veis aleat??rias, para an??lise do comportamento assim??trico e dos eventos extremos. No primeiro ensaio a fun????o de produ????o tradicional ?? modelada utilizando vine-c??pulas para as rmas dos EUA, Alemanha e Inglaterra, assim foi poss??vel a constru????o de distribui????es multivariadas e estima????o dos pares de vari??veis produto-capital (y????k); produto-trabalho (y????l); capital-trabalho dado uma produ????o (k????ljy); e conhecer as estruturas de depend??ncias associadas, avaliando a depend??ncia n??o linear e as caudas pesadas. Para o segundo ensaio, segue os dados e procedimentos metodol??gicos do primeiro ensaio, utilizando vine-c??pulas e a constru????o dos par??metros e coe cientes de depend??ncia s??o os mesmos. A diferen??a est?? na modelagem de fronteira estoc??stica e na abordagem de e ci??ncia utilizando esse novo instrumento estat??stico. As distribui????es marginais foram estimadas utilizando a fun????o gamma e a fun????o normal, foram encontradas v??rias fam??lias de c??pulas, entre elas Gumbel, Student-t, BB7, Normal e Clayton que implica em mudan??as no comportamento e na depend??ncia de cada par de vari??veis ao longo dos anos e em cada pa??s, al??m de mostrar as caudas pesadas onde as rmas de grande e/ou pequeno porte se concentram. Essa mudan??a nas fam??lias con rmam o comportamento estoc??stico nos dados e da fun????o de produ????o, em contraste com o uso inadequado de fun????es deterministicas e hip??tese de normalidade multivariada.
42

Caracterização físico-química da maturação da uva Bordô sobre diferentes porta-enxertos

Pozzan, Maria Suzana Vial 10 December 2008 (has links)
Made available in DSpace on 2017-07-10T17:37:31Z (GMT). No. of bitstreams: 1 Maria Suzana Vial Pozzan.pdf: 492113 bytes, checksum: 34c211f5e25ea5c5cf9b1898973945c8 (MD5) Previous issue date: 2008-12-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Bordô grape is highlighted by its potential to produce juices and wines with high levels of color pigments. Different rootstocks have been available in the western region of Parana State in the formation of vines, but are few scientific reports on the behavior of different rootstocks on the physical and chemical characteristics of the grapes when used under the Bordô vine. Therefore, this study aimed to evaluate the rootstocks '420A', 'IAC 766' and 'Riparia of Traviú' in three moments of physiological ripeness of grapes on the technological characteristics of post-harvest grapes of the Bordô varieties. Considering the season 2007/2008, the experiment was conducted in vine located at Missal city, Paraná State, Brazil. The maturation stages were established based on sampling conducted through the collection of three bunches per plant in three distinct periods of fruit maturity, according to the color of the shell surface of the fruits, which were the color green to slightly arroxeado (Stage 1) , the purple (Stage 2) and purple intense (stage 3). The field experiment was conducted in a split plot in 3x3 factorial design in randomized blocks with seven repetitions, three treatments for rootstocks in the plot, and in the sub-plot three stages of maturation, where each plot was composed of five plants and and observed the three plants from the center. This study determined the following characteristics: mass of the rachis, fruits and bunch; and length, diameter and number of fruits. The chemical characteristics were: pH, total acidity, soluble solids, anthocyanins, Vitamin C, total polyphenols and tannins. In the results were applied analysis of variance, F test and Tukey test for comparison of means (p <0.05). The rootstock of Ripária of Traviú to presented the smallest value in relation the following characteristics the Bordô grape the rootstock IAC 766-Campinas was presented the best following productive characteristics. The rootstock 420A presented value of soluble solids higher this content moreover rootstock test. The 420A was the rootstock that presented smallest content anthocyanins suggesting that this rootstock was inferior the moreover rootstock in induction in fixation of color pigments of pellicle the Bordô grape, that is prejudicial that quality that your industrializes products. During of maturation Bordô grape ocorred accumulation of tannins of pellicle of fruits. The rootstock 420A presented rate of total polyphenols of pellicle higher that rootstocks IAC 766-Campinas and Ripária of Traviú / A uva Bordô se destaca pelo seu potencial de produzir sucos e vinhos com elevado teor de pigmentos corantes. Diversos porta-enxertos tem sido disponibilizados na região Oeste do Paraná para a condução de parreirais, porém são escassos os relatos científicos sobre o comportamento dos diferentes porta-enxertos utilizados frente às características físicas e químicas das uvas quando utilizadas sob a cultivar copa Bordô . Portanto, este trabalho teve como objetivos avaliar os porta-enxertos 420A , IAC 766-Campinas e Ripária do Traviú em três momentos fisiológicos da maturação das uvas sobre as características tecnológicas pós-colheita das uvas da cultivar copa Bordô . Considerando a safra 2007/2008, o experimento foi conduzido em parreiral localizado no município de Missal, PR. Os estádios de maturação foram estabelecidos com base em amostragens realizadas através da coleta de três cachos por planta em três períodos distintos da maturação dos frutos, segundo a coloração da superfície da película das bagas, cujas cores foram o esverdeado para levemente arroxeado (Estádio 1), o arroxeado (Estádio 2) e o arroxeado intenso (estádio 3). A coleta inicial (primeiro estádio) foi realizada com 90 dias da floração, em dezembro de 2007 e os intervalos entre as outras duas coletas foram de aproximadamente 8 dias. Foram determinadas as seguintes características físicas: massa do engaço, das bagas e do cacho e comprimento, diâmetro e número de bagas e as características químicas avaliadas foram: pH, Acidez Total Titulável, Sólidos Solúveis Totais, antocianinas, Vitamina C, Polifenóis totais e Taninos. Aos resultados foi aplicado Análise de Variância, teste F e teste Tukey de comparação de médias (p<0,05). O porta-enxerto Ripária do Traviú apresentou os menores valores em relação às características físicas da uva Bordô e o IAC 766-Campinas foi o porta-enxerto que apresentou as melhores características físicas produtivas. O porta-enxerto 420 A apresentou valor de sólidos solúveis superior aos demais porta-enxertos testados. O 420 A foi o porta-enxerto que apresentou conteúdos menores de antocianinas, sugerindo que este porta-enxerto seja inferior aos demais na indução da fixação de pigmentos corantes na película da uva Bordô , o que é prejudicial à qualidade de seus produtos industrializados. Durante a maturação da uva Bordô ocorreu acúmulo de taninos na película da baga. O porta-enxerto 420 A' apresentou índice de polifenóis totais da película superior aos dos porta-enxertos IAC 766-Campinas e Ripária do Traviú
43

Evaluating sex pheromone monitoring as a tool in the integrated management of vine mealybug, Planococcus ficus (signoret) (Homoptera: Pseudococcidae) / M.J. Kotze

Kotze, Maria Johanna January 2006 (has links)
The vine mealybug, Planococcus ficus (Signoret) (Homoptera: Pseudococcidae) is a pest with significant economic impact on the grape growing industry in South Africa and other parts of the world. With the isolation and synthesizing of the vine mealybug sex pheromone in 2001, new control options for the integrated management of the vine mealybug have been created. The status of sex pheromone monitoring as a tool in the integrated management of the vine mealybug has been evaluated from different perspectives. A significant quantitative difference in male vine mealybug trap catch numbers has been observed between wine and table grape vineyards and results indicated that there were differences in the susceptibility of grape cultivars to vine mealybug. Currently, the delta trap design is the accepted trap design for vine mealybug monitoring. No studies have yet been conducted to determine the optimum trap parameters like size or design. Population pressure may have an influence on the qualitative efficiency of various trap designs. The basis for degree-day forecasting models has been established adequately. However, refinements need to be done and the incorporation of factors such as humidity and regionality also need to be considered. Daily maximum temperatures fluctuating around the upper developmental threshold temperature for prolonged periods of time seemed to suppress population numbers. Different vineyard management practices exist for wine and table grape production. While an action threshold of 65 vine mealybug males per trap per two-week period seems an acceptable threshold for table grape production, it may not be appropriate for wine grape (or raisin grape) production. Using sex pheromone traps for population monitoring is a valid technique in the arsenal of management tactics against the vine mealybug. However, refinements and validation of research results must be done further to build credibility into the monitoring system. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2006.
44

Resourceful housing co-operative: the Vine Street project

January 1995 (has links) (PDF)
Thesis (M.Env. St.)--University of Adelaide University, Mawson Graduate Centre for Environmental Studies, 1995.
45

The initial impact of a small group Bible study ministry on a declining church

Greene, Perry Michael. January 1990 (has links)
Thesis (D. Min.)--Abilene Christian University, 1990. / Abstract. Includes bibliographical references (leaves 286-287).
46

"How good is the street?" a characteristic-based evaluation of Vine, Walnut, and Main streets, Cincinnati, Ohio /

Chittajallu, Dilip R. January 2004 (has links)
Thesis (Master of Community Planning)--University of Cincinnati, 2004. / Title from PDF t.p. (viewed Jan. 11, 2005). Includes bibliographical references.
47

Defining Sustainable Vine Balance for Cabernet Franc in Southern Illinois

Ray, Alexandra 01 May 2012 (has links)
In 2009 and 2010 a split, split, split plot experiment with training system, VSP or Smart-Dyson Ballerina (main plot), N, 0 or 33.6 kg/ha (split), crop level, 14.0, 18.7, or 23.4 clusters/m/canopy (split), clone, Cabernet Franc 1,4, 8 and 214 treatments with five replications were established in Union County, Illinois on mature vines. The Smart-Dyson Ballerina training system produced a Ravaz index that was 89% and 28% bigger compared to the VSP respectively in 2009 and 2010. In 2009, the Smart-Dyson Ballerina produced a 80% bigger yield than VSP and in 2010 yield was also larger, but influenced by both training system and crop level. Maintaining a balanced vineyard can increase profit for the grower by up to $6,356.87/ha.
48

Gaussian copula modelling for integer-valued time series

Lennon, Hannah January 2016 (has links)
This thesis is concerned with the modelling of integer-valued time series. The data naturally occurs in various areas whenever a number of events are observed over time. The model considered in this study consists of a Gaussian copula with autoregressive-moving average (ARMA) dependence and discrete margins that can be specified, unspecified, with or without covariates. It can be interpreted as a 'digitised' ARMA model. An ARMA model is used for the latent process so that well-established methods in time series analysis can be used. Still the computation of the log-likelihood poses many problems because it is the sum of 2^N terms involving the Gaussian cumulative distribution function when N is the length of the time series. We consider an Monte Carlo Expectation-Maximisation (MCEM) algorithm for the maximum likelihood estimation of the model which works well for small to moderate N. Then an Approximate Bayesian Computation (ABC) method is developed to take advantage of the fact that data can be simulated easily from an ARMA model and digitised. A spectral comparison method is used in the rejection-acceptance step. This is shown to work well for large N. Finally we write the model in an R-vine copula representation and use a sequential algorithm for the computation of the log-likelihood. We evaluate the score and Hessian of the log-likelihood and give analytic solutions for the standard errors. The proposed methodologies are illustrated using simulation studies and highlight the advantages of incorporating classic ideas from time series analysis into modern methods of model fitting. For illustration we compare the three methods on US polio incidence data (Zeger, 1988) and we discuss their relative merits.
49

Bayesian Network Approach to Assessing System Reliability for Improving System Design and Optimizing System Maintenance

January 2018 (has links)
abstract: A quantitative analysis of a system that has a complex reliability structure always involves considerable challenges. This dissertation mainly addresses uncertainty in- herent in complicated reliability structures that may cause unexpected and undesired results. The reliability structure uncertainty cannot be handled by the traditional relia- bility analysis tools such as Fault Tree and Reliability Block Diagram due to their deterministic Boolean logic. Therefore, I employ Bayesian network that provides a flexible modeling method for building a multivariate distribution. By representing a system reliability structure as a joint distribution, the uncertainty and correlations existing between system’s elements can effectively be modeled in a probabilistic man- ner. This dissertation focuses on analyzing system reliability for the entire system life cycle, particularly, production stage and early design stages. In production stage, the research investigates a system that is continuously mon- itored by on-board sensors. With modeling the complex reliability structure by Bayesian network integrated with various stochastic processes, I propose several methodologies that evaluate system reliability on real-time basis and optimize main- tenance schedules. In early design stages, the research aims to predict system reliability based on the current system design and to improve the design if necessary. The three main challenges in this research are: 1) the lack of field failure data, 2) the complex reliability structure and 3) how to effectively improve the design. To tackle the difficulties, I present several modeling approaches using Bayesian inference and nonparametric Bayesian network where the system is explicitly analyzed through the sensitivity analysis. In addition, this modeling approach is enhanced by incorporating a temporal dimension. However, the nonparametric Bayesian network approach generally accompanies with high computational efforts, especially, when a complex and large system is modeled. To alleviate this computational burden, I also suggest to building a surrogate model with quantile regression. In summary, this dissertation studies and explores the use of Bayesian network in analyzing complex systems. All proposed methodologies are demonstrated by case studies. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2018
50

MANEJO DA IRRIGAÇÃO PELO MÉTODO PENMAM MONTEITH NA CULTURA DA VIDEIRA / MANAGEMENT OF IRRIGATION METHOD FOR THE CULTURE OF PENMAM MONTEITH VINE

Turchiello, Maurício Scalvenzi 26 September 2011 (has links)
This study evaluated the effect of different irrigation levels by the yield components and quality of fruit of vine. The experiment was conducted at the experimental cultivation of grapes in the Polytchnic School of University of Santa Maria in Santa Maria, RS, and was utilized the variety Vênus, by the trellis way beteween october 1, 2010 and january 5, 2011 for gain the experiment data. The experimental design was ramdomized blocks with five treatments and four replications. It was determined a irrigation level of reference in accordance with the characteristic curve of water retention in soil. The irrigations were performed whenever the cumulative evapotranspiration in the period approaching the value of water deth reference. Irrigations treatments were called T2, T3, T4 and T5 corresponding the fractions 50, 75, 100, and 125% of water deth reference, and a control treatment (T1) that received no irrigation. It was evaluated the following parameters: by the plant, productivity and number of bunches.plant-1, by the fruit, weight, lenght and width of the bunch, number of the berries.cluster-1, weight of five berries, berry weight and diameterof of the stalk, hydrogenic potential and total soluble solids. The data used to evaluated the parameters through regression analysis are homogeneous and normal, without changes. The resuts of this study showed a significant difference (5%) for some parameters evaluated between the irrigated treatments and the control. Treatment with the highest productivity was the T4, with a yield of 17.794 kg.ha-1, an increase in productivity of 72,84% over the treatment without irrigation, however the effect on quality of the bunch was not significant. Given these results, the conditions under which the experiment was conducted, it is concluded that for the culture of the vine there is an increase in productivity related to the increase of irrigation water applied to a certain limit, after wich this increase in prodictivity is lower, without changind the quality of fruit. / Com o objetivo de avaliar o efeito de diferentes lâminas de irrigação em relação a produtividade, aos componentes de rendimento e aos atributos físicoquimicos do mosto da cultura da videira, foi conduzido um experimento na área experimental de cultivo de uvas no Colégio Politécnico da Universidade Federal de Santa Maria no município de Santa Maria - RS. Foi utilizada a cultivar Vênus, conduzida sob sistema de latada durante o período de 01 de outubro de 2010 a 05 de janeiro de 2011. A área onde foi instalado o experimento situa-se ao lado da estação meteorológica da Universidade Federal de Santa Maria do qual foram retirados os dados climáticos para o cálculo da evapotranspiração de referência pelo método de Penman-Monteith. O delineamento experimental utilizado foi blocos casualizados com cinco tratamentos e quatro repetições. Foi determinada uma lâmina de irrigação de referência. Os tratamentos das irrigações realizadas foram chamados de T2, T3, T4 e T5 e correspondem às frações de 50, 75, 100, 125% da lâmina de irrigação de referência, e um tratamento testemunha (T1) que não recebeu irrigação. Foram avaliados parâmetros da planta (produtividade e número de cachos.planta-1), do cacho (peso dos cachos, dimensões dos cachos, número de bagas.cacho-1, peso de cinco bagas, diâmetro das bagas e peso do engaço) e do mosto (pH e teor de sólidos solúveis totais). Os resultados obtidos neste trabalho mostraram que houve diferença significativa para os parâmetros avaliados, entre os tratamentos irrigados e a testemunha. O tratamento que apresentou maior incremento de produtividade foi o T4, com rendimento de 17.794 Kg.ha-1, correspondendo a um aumento de produtividade 72,84% em relação ao T1 sem irrigação, no entanto, o efeito sobre os atributos físico-quimicos do mosto não foi significativo. Diante desses resultados, nas condições em que o experimento foi realizado, conclui-se que para a cultura da videira, ocorre um aumento de produtividade relacionado ao aumento da lâmina de irrigação, até um determinado limite, após este limite, o incremento de produtividade é reduzido.

Page generated in 0.0506 seconds