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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.
861

Applications of Spatio-temporal Analytical Methods in Surveillance of Ross River Virus Disease

Hu, Wenbiao January 2005 (has links)
The incidence of many arboviral diseases is largely associated with social and environmental conditions. Ross River virus (RRV) is the most prevalent arboviral disease in Australia. It has long been recognised that the transmission pattern of RRV is sensitive to socio-ecological factors including climate variation, population movement, mosquito-density and vegetation types. This study aimed to assess the relationships between socio-environmental variability and the transmission of RRV using spatio-temporal analytic methods. Computerised data files of daily RRV disease cases and daily climatic variables in Brisbane, Queensland during 1985-2001 were obtained from the Queensland Department of Health and the Australian Bureau of Meteorology, respectively. Available information on other socio-ecological factors was also collected from relevant government agencies as follows: 1) socio-demographic data from the Australia Bureau of Statistics; 2) information on vegetation (littoral wetlands, ephemeral wetlands, open freshwater, riparian vegetation, melaleuca open forests, wet eucalypt, open forests and other bushland) from Brisbane City Council; 3) tidal activities from the Queensland Department of Transport; and 4) mosquito-density from Brisbane City Council. Principal components analysis (PCA) was used as an exploratory technique for discovering spatial and temporal pattern of RRV distribution. The PCA results show that the first principal component accounted for approximately 57% of the information, which contained the four seasonal rates and loaded highest and positively for autumn. K-means cluster analysis indicates that the seasonality of RRV is characterised by three groups with high, medium and low incidence of disease, and it suggests that there are at least three different disease ecologies. The variation in spatio-temporal patterns of RRV indicates a complex ecology that is unlikely to be explained by a single dominant transmission route across these three groupings. Therefore, there is need to explore socio-economic and environmental determinants of RRV disease at the statistical local area (SLA) level. Spatial distribution analysis and multiple negative binomial regression models were employed to identify the socio-economic and environmental determinants of RRV disease at both the city and local (ie, SLA) levels. The results show that RRV activity was primarily concentrated in the northeast, northwest and southeast areas in Brisbane. The negative binomial regression models reveal that RRV incidence for the whole of the Brisbane area was significantly associated with Southern Oscillation Index (SOI) at a lag of 3 months (Relative Risk (RR): 1.12; 95% confidence interval (CI): 1.06 - 1.17), the proportion of people with lower levels of education (RR: 1.02; 95% CI: 1.01 - 1.03), the proportion of labour workers (RR: 0.97; 95% CI: 0.95 - 1.00) and vegetation density (RR: 1.02; 95% CI: 1.00 - 1.04). However, RRV incidence for high risk areas (ie, SLAs with higher incidence of RRV) was significantly associated with mosquito density (RR: 1.01; 95% CI: 1.00 - 1.01), SOI at a lag of 3 months (RR: 1.48; 95% CI: 1.23 - 1.78), human population density (RR: 3.77; 95% CI: 1.35 - 10.51), the proportion of indigenous population (RR: 0.56; 95% CI: 0.37 - 0.87) and the proportion of overseas visitors (RR: 0.57; 95% CI: 0.35 - 0.92). It is acknowledged that some of these risk factors, while statistically significant, are small in magnitude. However, given the high incidence of RRV, they may still be important in practice. The results of this study suggest that the spatial pattern of RRV disease in Brisbane is determined by a combination of ecological, socio-economic and environmental factors. The possibility of developing an epidemic forecasting system for RRV disease was explored using the multivariate Seasonal Auto-regressive Integrated Moving Average (SARIMA) technique. The results of this study suggest that climatic variability, particularly precipitation, may have played a significant role in the transmission of RRV disease in Brisbane. This finding cannot entirely be explained by confounding factors such as other socio-ecological conditions because they have been unlikely to change dramatically on a monthly time scale in this city over the past two decades. SARIMA models show that monthly precipitation at a lag 2 months (=0.004,p=0.031) was statistically significantly associated with RRV disease. It suggests that there may be 50 more cases a year for an increase of 100 mm precipitation on average in Brisbane. The predictive values in the model were generally consistent with actual values (root-mean-square error (RMSE): 1.96). Therefore, this model may have applications as a decision support tool in disease control and risk-management planning programs in Brisbane. The Polynomial distributed lag (PDL) time series regression models were performed to examine the associations between rainfall, mosquito density and the occurrence of RRV after adjusting for season and auto-correlation. The PDL model was used because rainfall and mosquito density can affect not merely RRV occurring in the same month, but in several subsequent months. The rationale for the use of the PDL technique is that it increases the precision of the estimates. We developed an epidemic forecasting model to predict incidence of RRV disease. The results show that 95% and 85% of the variation in the RRV disease was accounted for by the mosquito density and rainfall, respectively. The predictive values in the model were generally consistent with actual values (RMSE: 1.25). The model diagnosis reveals that the residuals were randomly distributed with no significant auto-correlation. The results of this study suggest that PDL models may be better than SARIMA models (R-square increased and RMSE decreased). The findings of this study may facilitate the development of early warning systems for the control and prevention of this widespread disease. Further analyses were conducted using classification trees to identify major mosquito species of Ross River virus (RRV) transmission and explore the threshold of mosquito density for RRV disease in Brisbane, Australia. The results show that Ochlerotatus vigilax (RR: 1.028; 95% CI: 1.001 - 1.057) and Culex annulirostris (RR: 1.013, 95% CI: 1.003 - 1.023) were significantly associated with RRV disease cycles at a lag of 1 month. The presence of RRV was associated with average monthly mosquito density of 72 Ochlerotatus vigilax and 52 Culex annulirostris per light trap. These results may also have applications as a decision support tool in disease control and risk management planning programs. As RRV has significant impact on population health, industry, and tourism, it is important to develop an epidemic forecast system for this disease. The results of this study show the disease surveillance data can be integrated with social, biological and environmental databases. These data can provide additional input into the development of epidemic forecasting models. These attempts may have significant implications in environmental health decision-making and practices, and may help health authorities determine public health priorities more wisely and use resources more effectively and efficiently.
862

Dinâmica não linear de m Pêndula eletromecânico com excitação vertical

Elias, Leandro José [UNESP] 27 April 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-27Bitstream added on 2014-06-13T19:55:23Z : No. of bitstreams: 1 elias_lj_me_sjrp.pdf: 456982 bytes, checksum: 012c9b4ab5b1b167819de6d4b46a698b (MD5) / Este trabalho apresenta um estudo de um pêndulo eletromecânico com excitação vertical utilizando a teoria de perturbações. O objetivo é fazer um estudo analítico para verificar os efeitos de ressonância no estado estacionário do sistema, efeitos esses provocados por alguns valores de freqüência do sistema dinˆamico. As equações do sistema dinâmico estudado apresentam características que impedem a obtenção de soluções analíticas devido à presença de termos não lineares, e ainda exibem interações ressonantes entre bloco, motor e pêndulo. A análise feita considerou o sistema com ressonância entre o bloco e o motor, mas foi descartada a interação ressonante com o pêndulo. Como a excitação no suporte é vertical, em primeira aproximação a equação do pêndulo é a equação de Mathieu. Devido à presença de um termo não linear nesta equação, foi feito também um estudo com a teoria de perturbações para obter uma solução analítica aproximada, tomando como exemplo a equação de Mathieu analisada no estudo desenvolvido por Nayfeh. As equações para o estado estacionário do sistema foram obtidas através da aplicação de um método de perturbação. O estudo dessas equações foi baseado no trabalho desenvolvido por Kononenko, e os resultados obtidos são análogos, pois o sistema dinâmico deste estudo e o sistema dinâmico considerado por Kononenko guardam certa semelhança. / In this work a study of an electromechanical pendulum with a vertical excitation is done using the Perturbation theory. The main objective is to make an approximate analytic study to verify the effects of resonance at the stationary state of the system, effects that are caused by some values of frequencies of the dynamic system. The equations of the system show characteristics that don’t permit the analytic solutions because of presence of nonlinear terms and there are resonant interactions between the block, the eccentric mass and the pendulum. In this analysis the resonance between the block and the eccentric mass was considered, but the resonance with the pendulum was ignored. As the excitation of the support is vertical, the first approximation of the equation of the pendulum is a Mathieu equation. Due to the presence of one nonlinear term in this equation, a study with the perturbation theory was performed to get a solution at first approximation, following the study made by Nayfeh. The equations for the stationary state were taken through the application of one perturbation method. The study of these equations was based on the work developed by Kononenko and the results obtained are similar, because the dynamic system of this work and the system considered by Kononenko keep certain similarities.
863

An analytical research into the price risk management of the soft commodities futures markets

Rossouw, Werner 30 November 2007 (has links)
Agriculture is of inestimable value to South Africa because it is a major source of job creation and plays a key role in earning foreign exchange. The most significant contribution of agriculture, and in particular maize, is its ability to provide food for the nation. For a number of decades government legislation determined prices, and as such the trade of grains on the futures exchange requires market participants to adapt to a volatile environment. The research focuses on the ability of market participants to effectively mitigate price volatility on the futures exchange through the use of derivative instruments, and the possibility of developing risk management strategies that will outperform the return offered by the market. The study shows that market participants are unable to use derivative instruments in such a way that price volatility is minimised. The findings of the study also indicate that the development of derivative risk management strategies could result in better returns than those offered by the market, mainly by exploiting trends on the futures market. / Financial Accounting / M. Comm. (Business Management)
864

Évaluation du POCIS (Polar Organic Chemical Integrative Sampler) : domaine de validité et performances pour 56 micropolluants organiques : application aux hormones, pharmaceutiques, alkyphénols, filtre UV et pesticides / POCIS evaluation : application fields and performances for 56 organic micropollutants : application for hormones, pharmaceuticals, alkylphenols, UV filter and pesticides

Morin, Nicolas 16 April 2013 (has links)
Le POCIS (Polar Organic Chemical Integrative Sampler) est un outil d'échantillonnage intégratif alternatif aux techniques d'échantillonnages classiques (ponctuelle ou automatisée) dédié à la mesure de micropolluants organiques relativement hydrophiles dans les eaux. Cet outil permet d'intégrer les concentrations dans le temps (CTWA, Time-Weighted Average Concentration) et, dans certains cas, d'abaisser les limites de quantification. Une revue bibliographique détaillée a montré la forte variabilité des données de performances du POCIS mesurées en laboratoire (notamment les taux d'échantillonnage ou Rs). Cette variabilité résulte en majeure partie de systèmes expérimentaux d'étalonnage différents selon les études et pas toujours renseignés. Dans la littérature, les CTWA obtenues in situ sont comparées aux concentrations obtenues après échantillonnage classique, tel que mis en œuvre actuellement dans les programmes de surveillance européens ; ces concentrations sont dans la plupart des cas du même ordre de grandeur, même si elles ne représentent pas tout à fait la même information. Avec comme objectif d'obtenir des CTWA les plus justes et robustes possibles, nous avons étudié le comportement du POCIS « pharmaceutique » en laboratoire vis-à-vis de 56 micropolluants (hormones, pharmaceutiques, alkylphénols, pesticides, filtre UV), dans un système expérimental d'étalonnage conçu spécifiquement pour contrôler l'ensemble des conditions expérimentales ayant une influence sur les Rs. Nous avons ainsi déterminé 43 Rs robustes et démontré que le POCIS est bien adapté à l'échantillonnage de la plupart des molécules étudiées. De plus, l'allure des cinétiques d'accumulation est expliquée à l'aide des propriétés physico-chimiques des molécules (log D , surface polaire). Cinq homologues deutérés ont été identifiés en tant que PRC (Performance Reference Compounds), c'est-à-dire qu'ils peuvent être utilisés pour corriger les différences de conditions entre le laboratoire et le terrain. Nous avons également comparé le POCIS au Chemcatcher « polaire » en laboratoire et montré qu'en terme de domaine d'application et de performances, le POCIS est mieux adapté pour les micropolluants étudiés. Enfin, nous avons testé la justesse et la robustesse du POCIS lors de deux essais inter-laboratoires (EIL). Le premier EIL, portant sur l'étalonnage de l'outil en laboratoire, a démontré la robustesse de ses performances pour 3 pesticides. Le deuxième EIL in situ a démontré la pertinence du POCIS pour échantillonner des hormones, des pharmaceutiques et des pesticides dans un effluent de station d'épuration. Cette thèse permet d'avancer dans le domaine des connaissances sur l'outil POCIS et de favoriser son application dans le cadre de la directive sur l'eau / The POCIS (Polar Organic Chemical Integrative Sampler) is an alternative integrative sampling tool to conventional sampling methods (grab or automated) for measuring hydrophilic organic micropollutants in water. This tool permits to supply time-weighted average concentrations (TWAC) and, sometimes, to decrease limits of quantification. A detailed bibliographic review showed the important variability of POCIS performance data measured in laboratory (notably the sampling rates or Rs). This variability is in majority due to different experimental calibration systems, not always well detailed, among studies. In the literature, in situ TWAC are compared to concentrations from conventional sampling, actually used in European monitoring programs ; these concentrations are generally of the same order of magnitude, even if they do not represent the same information. In order to obtain accurate and robust TWAC, we studied in laboratory the “pharmaceutical” POCIS behavior for 56 micropollutants (hormones, pharmaceuticals, alkylphenols, pesticides, UV filter), in a calibration system specifically made for controlling the whole experimental conditions having an influence on Rs. We determined 43 robust RS and demonstrated that POCIS is well adapted for sampling most of studied molecules. Moreover, the pattern of kinetic accumulations is explained using molecule physical-chemical properties (log D, polar surface). Five deuterated homologues were identified as PRCs, meaning that they can be used for correcting differences in conditions between the laboratory and the field. We also compared the POCIS with the “polar” Chemcatcher and we showed that in term of application field and performances, the POCIS is better adapted for studied micropollutants. At last, we tested the accuracy and the robustness of the POCIS during two inter-laboratory studies (ILSs). The first ILS, dealing with the laboratory calibration of the tool, demonstrated performance robustness for 3 pesticides. The second in situ ILS demonstrated the relevance of the POCIS for sampling hormones, pharmaceuticals and pesticides from a waste water treatment plant effluent. This thesis permits to improve knowledge on the POCIS and to promote its application for the water framework directive
865

Mitigating the effect of soft-limiting for OFDM peak reduction

Bibi, Nargis January 2014 (has links)
Digital communication systems which use Orthogonal Frequency Division Multiplexing (OFDM) are now widely used and have many advantages. The main disadvantage is the requirement for highly linear analogue electronics including the high power amplifier (HPA). This requirement cannot be met in all circumstances because of the occurrence of symbols with high peak to average power ratio (PAPR). Such symbols may be non-linearly distorted by limiting. Approaches to solve this problem have been either to reduce the PAPR at the transmitter or to try to mitigate the effect of the non-linearity at the receiver. Soft-limiting, i.e. applying limiting in software prior to the HPA is a simple way to reduce the PAPR. It produces non-linear distortion which will cause an increase in the bit-error-rate (BER) at the receiver. This thesis surveys existing alternatives ways of reducing the effect of non-linearity and proposes some new ones. Two iterative receiver techniques, based on statistical analysis of the nature of the non-linearity, have been implemented and investigated. These are the ‘Bussgang Noise Cancellation’ (BNC) technique and the ‘Decision Aided Reconstruction’ (DAR) techniques. As these techniques are valid for any memory-less nonlinearity, an alternative form of limiting, named as Inverted-Wraparound (IWRAP) has been included in the BNC investigation. A new method is proposed which is capable of correcting the received time-domain samples that are clipped, once they have been identified. This is named the ‘Equation-Method’ and it works by identifying constellation symbols that are likely to be correct at the receiver. If there are a sufficient number of these and they are correctly identified, the FFT may be partitioned to produce a set of equations that may be solved for the clipped time-domain samples. The thesis proposes four enhancements to this new method which improve its effectiveness. It is shown that the best form of this method outperforms conventional techniques especially for severe clipping levels. The performance of these four enhancements is evaluated over channels with additive white Gaussian noise (AWGN) in addition to clipping distortion. A technique based on a ‘margin factor’ is designed to make these methods work more effectively in the presence of AWGN noise. A new combining algorithm referred as ‘HARQ for Clipping’ is presented where soft bit decisions are combined from multiple transmissions. ‘HARQ for Clipping’ has been combined with the best version of the Equation-Method, and the performance of this approach is evaluated in terms of the BER with different levels of AWGN. It has been compared to other approaches from the literature and was found to out-perform the BNC iterative receiver by 3dB at signal to noise ratios around 10dB. Without HARQ, the best version of the Equation-Method performs better than the BNC receiver, at signal-to-nose ratios above about 17dB.
866

Análise de taxa média de bloqueio em conexões por algoritmos de caminhos mínimos: algoritmo de Yen e algoritmo genético / Average Analysis in blocking connections shortest paths algorithm: Yen algorithm and a genetic algorithm

Barreto, Tarcisio da Silva 15 December 2014 (has links)
Made available in DSpace on 2016-08-31T13:33:41Z (GMT). No. of bitstreams: 1 TarcisioSB_DISSERT.pdf: 1571314 bytes, checksum: 86e8646fa8da6455187767e219181490 (MD5) Previous issue date: 2014-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Studies on connections lock in computer networks have been gaining prominence in recent research focused on computational communication and technology. Several researchers have used various methods in order to identify and minimize the blocking rate that prevent a connection is established. This paper presents a blocking rate analysis in connections of shortest paths algorithms. They have on the performance of a transparent optical network. Two algorithms will be used to perform the analysis and simulations, the Genetic Algorithm (AG) and the algorithm Yen (AY). The Genetic Algorithm is based on Computational Intelligence (CI) and the Yen algorithm is based on the principle of finding and identifying the K shortest paths. Numerical simulations performed on different network scenarios show that the greater the number of connections, the higher the blocking rate in the connections. This study will help to identify which algorithm behaves better in the specific cases described in this work / Os estudos sobre bloqueio de conexões em redes de computadores vêm ganhando destaque em recentes pesquisas voltadas à comunicação computacional e tecnologia. Vários pesquisadores têm utilizado diversos métodos buscando identificar e minimizar ao máximo a taxa média de bloqueio que impedem que uma conexão seja estabelecida. Este trabalho apresenta uma análise de taxa média de bloqueio em conexões por algoritmos de caminhos mínimos. Têm sobre o desempenho de uma rede ótica transparente. Serão utilizados dois algoritmos para realizar a análise e as simulações, o Algoritmo Genético (AG) e o Algoritmo de Yen (AY). O Algoritmo Genético fundamentado por Inteligência Computacional (IC) e o Algoritmo de Yen baseado no princípio de encontrar e identificar os K menores caminhos. Simulações numéricas realizadas em diferentes cenários da rede mostram que, quanto maior o número de conexões, maior será a taxa média de bloqueio nas conexões. Através desse estudo será possível identificar qual algoritmo se comporta melhor para os casos específicos descritos nesse trabalho
867

Estratégias de momentum no mercado cambial

Silva, Kesley Leandro da 15 February 2016 (has links)
Submitted by Kesley Leandro da Silva (kesley.leandro@gmail.com) on 2016-03-10T17:32:09Z No. of bitstreams: 1 Dissertação v02.docx: 272937 bytes, checksum: 8b3b51152e65026481b1ba2a1541fcde (MD5) / Rejected by Renata de Souza Nascimento (renata.souza@fgv.br), reason: Kesley, Segue abaixo as alterações que deverão ser realizadas em seu trabalho: - O arquivo deve estar em pdf. - Nome e Título em Letra maiúscula. - Retirar a sigla SP que consta ao lado de SÃO PAULO. - A ficha catalográfica deve estar na parte inferior da pagina - Centralizar os títulos Resumo e Abstract - As páginas anteriores da Introdução não podem estar numeradas. Em seguida, submeter novamente o trabalho. Att on 2016-03-10T21:57:30Z (GMT) / Submitted by Kesley Leandro da Silva (kesley.leandro@gmail.com) on 2016-03-11T15:24:37Z No. of bitstreams: 1 Dissertação v03.pdf: 1405923 bytes, checksum: 28d2a1fb855d75506c6f1f010f4ff5a5 (MD5) / Approved for entry into archive by Renata de Souza Nascimento (renata.souza@fgv.br) on 2016-03-11T15:42:19Z (GMT) No. of bitstreams: 1 Dissertação v03.pdf: 1405923 bytes, checksum: 28d2a1fb855d75506c6f1f010f4ff5a5 (MD5) / Made available in DSpace on 2016-03-11T16:00:12Z (GMT). No. of bitstreams: 1 Dissertação v03.pdf: 1405923 bytes, checksum: 28d2a1fb855d75506c6f1f010f4ff5a5 (MD5) Previous issue date: 2016-02-15 / Utilizo dados semanais para investigar a lucratividade de estratégias de momentum no mercado de câmbio baseadas em dois diferentes métodos de extração da tendência, possivelmente não linear. Comparo a performance com as tradicionais regras de médias móveis, método linear bastante utilizado pelos profissionais do mercado. Eu encontro que o desempenho de todas as estratégias é extremamente sensível à escolha da moeda, às defasagens utilizadas e ao critério de avaliação escolhido. A despeito disso, as moedas dos países do G10 apresentam resultados médios melhores com a utilização dos métodos não lineares, enquanto as moedas dos países emergentes apresentam resultados mistos. Adoto também uma metodologia para o gerenciamento do risco das estratégias de momentum, visando minimizar as 'grandes perdas'. Ela tem êxito em diminuir as perdas máximas semanais, o desvio-padrão, a assimetria e curtose para a maior parte das moedas em ambas as estratégias. Quanto ao desempenho, as operações baseadas no filtro HP com gestão do risco apresentam retornos e índices de Sharpe maiores para cerca de 70% das estratégias, enquanto as baseadas na regressão não paramétrica apresentam resultados melhores para cerca de 60% das estratégias. / I use weekly data to investigate the profitability of momentum strategies in the currency market based on two different methods of trending extraction, possibly nonlinear. I compare the performance with the traditional moving averages rules, linear method of trading broadly used by market professionals. I find that the performance of all strategies is extremely sensitive to the choice of currency, lags parameters and the evaluation criteria. Nevertheless, the G10 currencies show better average results with the nonlinear methods, while the emerging market currencies show mixed results. I also adopt a methodology for managing the risk of momentum strategies to minimize the “worst crashes”. It works to lower the maximum weekly losses, the standard deviation, the skewness and the kurtosis for most currencies in both strategies. In terms of performance, HP filter with risk-managed momentum shows higher return and Sharpe ratio for about 70% the observations, while those based on nonparametric regression show higher numbers for about 60% the observations.
868

Determinação do custo médio ponderado de capital regulatório para distribuidoras de gás natural

Villela, João Paulo Mesquita 18 January 2018 (has links)
Submitted by João Paulo Mesquita Villela (jpmv_nit@yahoo.com.br) on 2018-03-05T22:41:17Z No. of bitstreams: 1 Dissertação JP - WACC-GN - Final.pdf: 4843974 bytes, checksum: 53a8c6a560387b7ac0c7d2f370bdc655 (MD5) / Approved for entry into archive by GILSON ROCHA MIRANDA (gilson.miranda@fgv.br) on 2018-03-12T15:00:37Z (GMT) No. of bitstreams: 1 Dissertação JP - WACC-GN - Final.pdf: 4843974 bytes, checksum: 53a8c6a560387b7ac0c7d2f370bdc655 (MD5) / Made available in DSpace on 2018-03-16T17:17:30Z (GMT). No. of bitstreams: 1 Dissertação JP - WACC-GN - Final.pdf: 4843974 bytes, checksum: 53a8c6a560387b7ac0c7d2f370bdc655 (MD5) Previous issue date: 2018-01-18 / The objective of this work is to propose a methodology for determining the weighted average cost of capital to be employed by the regulatory agency in the tariff review process of natural gas distributors in the state of São Paulo. The challenge in this process is to establish a remuneration that guarantees the lowest cost with the greatest benefit to the customers and at the same time provides the maintenance of the economic balance and the incentive to expand the services provided by the concessionaires. The complexity of the study becomes evident when we verify the great dispersion of values proposed in the contributions sent to the Sanitation and Energy Regulatory Agency of the State of São Paulo (ARSESP) during the public consultation process. In this sense, the different approaches used by other regulatory agencies also make it difficult to establish a standardized solution to the problem. In this way, we analyzed initially the methodology defined by the ARSESP, the contributions received during the public consultation process carried out by the agency and some references of national and international regulatory practices. Finally, we sought to solve the issue by proposing a methodology considered adequate to estimate the weighted average cost of capital for the natural gas distributors in the state of São Paulo. / O objetivo deste trabalho é propor uma metodologia para a determinação do custo médio ponderado de capital a ser empregado pela agência reguladora no processo de revisão tarifária das distribuidoras de gás natural do estado de São Paulo. O desafio nesse processo é estabelecer uma remuneração que garanta o menor custo com o maior benefício para os clientes e ao mesmo tempo proporcione a manutenção do equilíbrio econômico e do estímulo a ampliação dos serviços prestados pelas concessionárias. A complexidade do estudo torna-se evidente ao verificarmos a grande dispersão de valores propostos nas contribuições enviadas a Agência Reguladora de Saneamento e Energia do Estado de São Paulo (ARSESP) durante o processo de consulta pública. Nesse sentido, as diferentes abordagens utilizadas por outras agências regulatórias também dificultam a definição de uma solução padronizada para o problema. Desta forma, analisou-se inicialmente a metodologia definida pela ARSESP, as contribuições recebidas durante o processo de consulta pública realizado por esta agência e referências das práticas regulatórias nacionais e internacionais. Finalmente, procurou-se solucionar a questão propondo uma metodologia considerada adequada para estimar o custo médio ponderado de capital para as distribuidoras de gás canalizado do estado de São Paulo.
869

Casca de mamona em dietas para ovinos de corte / Castor bean hulls in diets cut.

Beserra, Liandro Torres January 2010 (has links)
BESERRA, Liandro Torres. Casca de mamona em dietas para ovinos de corte. 2010. 80 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Zootecnia, Fortaleza-CE, 2010 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-03T13:50:38Z No. of bitstreams: 1 2010_dis_ltbeserra.pdf: 593748 bytes, checksum: ddf4e4ea9844d0f6222a6607d66473c8 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-03T13:50:54Z (GMT) No. of bitstreams: 1 2010_dis_ltbeserra.pdf: 593748 bytes, checksum: ddf4e4ea9844d0f6222a6607d66473c8 (MD5) / Made available in DSpace on 2016-08-03T13:50:54Z (GMT). No. of bitstreams: 1 2010_dis_ltbeserra.pdf: 593748 bytes, checksum: ddf4e4ea9844d0f6222a6607d66473c8 (MD5) Previous issue date: 2010 / The objective of this study was to evaluate four substitution levels (0, 33, 67 and 100%) of Tifton 85 hay by castor hulls on the diet of Morada Nova, males, non-castrated, crossbred sheep on average aged 7 months and weighting 20.3 kg so that it was possible to compare bioeconomic performance of each diet. The experimental design was established with four treatments and five repetitions. It has been used a 50% ratio between roughage and concentrated feed. Confinement lasted 70 days: 14 days of adaptation and 56 of data collection. It has been observed reductions on both progressive intake nutrient and animal performance, however, from 67% substitution level on, biological performance has dropped drastically. Increasing the percentage of substitution level has not resulted in significant changes on feedlot sheep behavioral characteristics. It has been observed both higher food and rumination efficiency with lower levels of castor hulls and also differences between on morphometric measures: body weight (PC), body weight at slaughter (PVA), empty body weight (PCV), hot carcass weight (PCQ), cold carcass weight (PCF) and empty body performance (RCV). Analyses on cut weights made on the carcass have presented differences on: half carcass, leg, loin back, shoulder, flank and neck. Concerning cut economic returns, leg and loin cuts later have presented differences between different substitution levels and regarding on non-carcass treatments, it has been observed economic differences for skin, head, feet, trachea/ lung/ tongue, diaphragm, heart, liver, spleen, kidney, omasum, rumen/ reticulum and for perirenal fat. Concerning to nutrients, 0-33% substitution level has presented best results followed by 67% substitution level, which has presented intermediate values, and 100% substitution level, with the worst results. Finally, it has been made technical, zootechnical and economical analysis based on both costs of each diet and dry matter (MS) consumption. Daily production (kg / PV) and productivity (kg / day x sheep) have been higher in production systems with smaller amount of castor hulls on the diet due to the higher consumption of dry matter (MS) which has resulted in: increased animal performance; higher number of animals with ideal weight to be slaughtered per year; and in higher gross income kg/ PV (R$/ month). On the other hand, total cost (R$/ month) decreases while increasing substitution levels, mainly because of the low prices of castor hulls. Results pointed on drastically feed decreasing costs on systems with higher castor hulls. 67% substitution level have presented the highest liquid income per year (R$ 4,600.00); a 1.04 cost-benefits relation; a 23% internal return rate (TIR); and a Liquid Present Value (VPL) of R$ 22,888.97. / Objetivou-se, com este trabalho, avaliar a influência de quatro níveis de substituição (0; 33; 67 e 100) do feno de capim-tifton 85 pela casca de mamona em rações sobre o desempenho bioeconômico de ovinos mestiços de Morada Nova, machos, inteiros, com peso vivo médio de 20,3 kg e idade média de 7 meses. O delineamento experimental empregado foi inteiramente casualizado com quatro tratamentos e cinco repetições. A ração formulada possuía uma relação volumoso (feno de capim-tifton 85 e/ou a casca de mamona): concentrado de 50%. O confinamento durou 70 dias, sendo 14 de adaptação e 56 de coleta. Houve redução progressiva no consumo dos nutrientes e no desempenho dos animais com a substituição do feno de capim-tifton 85 pela casca de mamona na dieta, no entanto, só partir do nível 67% de substituição do feno de capim-tifton 85 pela casca de mamona o rendimento biológico diminuiu acentuadamente. O aumento do percentual de substituição do feno de capimtifton 85 pela casca de mamona não propiciou grandes mudanças comportamentais dos ovinos confinados. Apenas nas eficiências de alimentação e de ruminação observou-se diferença nos níveis com menor porcentagem de casca de mamona na dieta dos animais, acarretando maiores eficiências. Foram obtidas diferenças entre os níveis de substituição sobre peso vivo (PV), peso vivo ao abate (PVA), peso de corpo vazio (PCV), pesos de carcaça quente (PCQ) e carcaça fria (PCF) e rendimento do corpo vazio (RCV). Também houve diferença para as medidas morfométricas. Em relação aos pesos dos cortes feitos na carcaça os que apresentaram diferenças foram os da meia carcaça, da perna, do lombo posterior, da paleta, da fraldinha e do pescoço. Quanto aos rendimentos dos cortes, a perna e o lombo posterior apresentaram diferenças entre os tratamentos. Para o peso dos constituintes não-carcaça, foram obtidas diferenças para pele, cabeça, pés, traquéia/pulmão/língua, diafragma, coração, fígado, rins, baço, omaso, rúmen/retículo e para gorduras perirenal, omental e mesentérica. Em geral, os níveis 0 e 33% de substituição foram os que apresentaram os melhores resultados, seguido do nível 67%, com valores intermediários, sendo o nível de 100% de casca de mamona o que apresentou os piores resultados. De posse do custo de cada ração e do consumo de matéria seca das mesmas, foram analisados os indicadores técnicos, zootécnicos e econômicos. A produção diária (kg/PV) e a produtividade (kg/ovino x dia) foram maiores nos sistemas de produção com menor porcentagem de casca de mamona na dieta dos animais, consequência do maior consumo de MS, resultando em um maior desempenho dos animais e um maior número de animais terminados por ano, gerando maior renda bruta kg/PV (R$/mês). Em contrapartida, o custo total (R$/mês) diminui com o aumento da substituição do feno de capim-tifton 85 pela casca de mamona na dieta animal, principalmente pelo baixo valor de aquisição da casca de mamona, reduzindo drasticamente os custos com alimentação nos sistemas com maior porcentagem de casca de mamona. O nível de substituição 67% de casca de mamona foi o que apresentou maior renda líquida anual (R$ 4600,00), relação benefício custo (1,04), valor presente líquido (R$ 22888,97) e taxa interna de retorno (23%).
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A comparative study of permutation procedures

Van Heerden, Liske 30 November 1994 (has links)
The unique problems encountered when analyzing weather data sets - that is, measurements taken while conducting a meteorological experiment- have forced statisticians to reconsider the conventional analysis methods and investigate permutation test procedures. The problems encountered when analyzing weather data sets are simulated for a Monte Carlo study, and the results of the parametric and permutation t-tests are compared with regard to significance level, power, and the average coilfidence interval length. Seven population distributions are considered - three are variations of the normal distribution, and the others the gamma, the lognormal, the rectangular and empirical distributions. The normal distribution contaminated with zero measurements is also simulated. In those simulated situations in which the variances are unequal, the permutation test procedure was performed using other test statistics, namely the Scheffe, Welch and Behrens-Fisher test statistics. / Mathematical Sciences / M. Sc. (Statistics)

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