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Ekonomika ČR v průběhu transformace ve srovnání s Polskem a Maďarskem. / Czech economy during the transformation in comparison with Poland and HungaryŠpičková, Hana January 2010 (has links)
This thesis deals with the transition of centrally planned economic system to market system, namely in the Czech Republic, Poland and Hungary. In the theoretical part are approximated goals and phases ot transformation and transformation strategies. Furthermore, the Washington consensus, the circumstances of its origin, its content and what position occupied in transition economies. The practical part monitor the development of individual economies in the period from 1990 until 2004. Development is not captured only by macroeconomic indicators (GDP, inflation, unemployment), but also by events that these indicators have an impact. Conclusion is devoted to an overall summary and assessment of the transformation process in all three countries.
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Estimação de estado em sistemas elétricos de potência: a interpretação geométrica aplicada ao processamento de erros de medidas, de parâmetros e de topologia / Power systems state estimation: the geometrical view applied to the processing of measurements, parameters and topological errorsBreno Elias Bretas de Carvalho 29 March 2018 (has links)
Este trabalho foi proposto com o objetivo de implementar uma ferramenta computacional para estimar os estados (tensões complexas nodais) de um sistema elétrico de potência e aplicar métodos alternativos para o processamento de erros topológicos, erros de parâmetros e/ou de erros grosseiros em medidas, baseados na interpretação geométrica dos erros e no conceito de inovação das medidas. O método utilizado para a resolução do problema de estimação de estado é o de mínimos quadrados ponderados. Através da interpretação geométrica, demonstrou-se matematicamente que o erro da medida é constituído de uma componente detectável e uma não-detectável, entretanto, as metodologias até então utilizadas para o processamento de erros consideram apenas a componente detectável do erro e, como consequência, podem falhar. Na tentativa de contornar essa limitação e baseado nos conceitos citados previamente, foi estudada e implementada uma metodologia alternativa para processar tais erros baseada na análise das componentes dos erros das medidas. Em primeiro lugar, é testado se o conjunto de medidas possui erros utilizando, para isso, o valor do erro de medida composto normalizado. Em seguida, diferencia-se se um ou outro erro ocorreu, ou mesmo se mais de um tipo de erro ocorreu. A correção a ser feita no parâmetro de linha ou na medida com erro grosseiro será o erro normalizado composto correspondente. A abordagem proposta neste trabalho requer somente um conjunto de medidas, e no mesmo instante. Para validação do programa, foram feitas diversas simulações nos sistemas de 14 e 57 barras do IEEE. / This work was proposed with the objective to implement a computational tool to estimate the states (nodal complex voltages) of a power system and apply alternative methods for the processing of topological errors, parameter errors and/or gross errors in measurements, based on the geometric interpretation of the errors and the innovation concept of measurements. The method used to solve the state estimation problem is the weighted least squares. Through geometric interpretation, it has been demonstrated mathematically that the measurement error is composed by a detectable component and a non-detectable, however, the methodologies heretofore used for error processing consider only the detectable component of the error and, consequently, can fail. In an attempt to overcome this limitation and based on the concepts mentioned previously, an alternative approach to process such errors was studied and implemented based on the analysis of the components of the measurements errors. Firstly, it is tested if the set of measurements has errors using, for that, the value of the composed measurement error in its normalized way. Next, it diers if either an error has occurred, or if more than one type of error occurred. The correction to be made in the line parameter or the measurement with gross error is the correspondent composed normalized error. The proposed approach in this paper requires only a set of measures, and at the same instant. To validate the software, several simulations were performed in the IEEE 14-bus and 57-bus systems.
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Avaliação da qualidade e redundância das medidas para estimação de estado em sistemas elétricos de potência / Measurements quality and redundancy evaluation for power system state estimationRaphael Augusto de Souza Benedito 28 February 2007 (has links)
Os centros de operação de sistemas elétricos de potência (SEP) exigem que uma vasta quantidade de informações esteja disponível para o controle e supervisão dos SEP. Em uma operação segura dos SEP é de suma importância que o processo de estimação de estado (EE) seja confiável. Visando este propósito, neste trabalho: i) propõe-se o desenvolvimento de um programa computacional que permita avaliar e aumentar a confiabilidade de um SEP em termos de qualidade e redundância das medidas disponíveis. Este programa fundamenta-se na fatoração da matriz Jacobiana transposta (\'H POT.t\') para realização da análise e restauração de observabilidade, e identificação de medidas críticas e conjuntos críticos de medidas. Para estimação de estado, é utilizado o algoritmo desacoplado rápido versão BX, e para a detecção e identificação de erros grosseiros, utiliza-se o teste dos resíduos normalizados; ii) propõe-se uma metodologia e um algoritmo para análise de observabilidade e identificação de ilhas observáveis, usando conceitos de caminhos de grafo e a fatoração triangular da matriz \'H POT. t\'. Para comprovar a eficiência das metodologias propostas, vários testes foram realizados, utilizando o sistema de 6, 14, 30 e 118 barras do IEEE. / The operating center requires much information in order to control and supervise the power systems. In a secure power systems operation it is important that the state estimation process be reliable. For that purpose, in this work: i) a computer program to evaluate and increment the reliability of power system in terms of redundancy and measurements availability is developed. That program is based on the \'H POT.t\' matrix factorization with the purpose of observability analysis and restoration; critical measurements and critical sets identification. The version BX of the fast decoupled algorithm for state estimation is used. Gross errors detection and identification is made through the normalized residue test; ii) using of path graph concepts a methodology and algorithm for network observability analysis and observable island identification is developed. To implement that algorithm, the triangular factorization of the transpose Jacobian matrix is used. To prove the efficiency of the proposed methodology, several tests were performed using the system of 6, 14, 30 and 118 buses from IEEE.
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Estimação de estado: a interpretação geométrica aplicada ao processamento de erros grosseiros em medidas / Study of systems with optical orthogonal multicarrier and consistentBreno Elias Bretas de Carvalho 22 March 2013 (has links)
Este trabalho foi proposto com o objetivo de implementar um programa computacional para estimar os estados (tensões complexas nodais) de um sistema elétrico de potência (SEP) e aplicar métodos alternativos para o processamento de erros grosseiros (EGs), baseados na interpretação geométrica dos erros e no conceito de inovação das medidas. Através da interpretação geométrica, BRETAS et al. (2009), BRETAS; PIERETI (2010), BRETAS; BRETAS; PIERETI (2011) e BRETAS et al. (2013) demonstraram matematicamente que o erro da medida se compõe de componentes detectáveis e não detectáveis, e ainda que a componente detectável do erro é exatamente o resíduo da medida. As metodologias até então utilizadas, para o processamento de EGs, consideram apenas a componente detectável do erro, e como consequência, podem falhar. Na tentativa de contornar essa limitação, e baseadas nos trabalhos citados previamente, foram estudadas e implementadas duas metodologias alternativas para processar as medidas portadoras de EGs. A primeira, é baseada na análise direta das componentes dos erros das medidas; a segunda, de forma similar às metodologias tradicionais, é baseada na análise dos resíduos das medidas. Entretanto, o diferencial da segunda metodologia proposta reside no fato de não considerarmos um valor limiar fixo para a detecção de medidas com EGs. Neste caso, adotamos um novo valor limiar (TV, do inglês: Threshold Value), característico de cada medida, como apresentado no trabalho de PIERETI (2011). Além disso, com o intuito de reforçar essa teoria, é proposta uma forma alternativa para o cálculo destes valores limiares, através da análise da geometria da função densidade de probabilidade da distribuição normal multivariável, referente aos resíduos das medidas. / This work was proposed with the objective of implementing a computer program to estimate the states (complex nodal voltages) in an electrical power system (EPS) and apply alternative methods for processing gross errors (GEs), based on the geometrical interpretation of the measurements errors and the innovation concept. Through the geometrical interpretation, BRETAS et al. (2009), BRETAS; PIERETI (2010), BRETAS; BRETAS; PIERETI (2011) and BRETAS et al. (2013) proved mathematically that the measurement error is composed of detectable and undetectable components, and also showed that the detectable component of the error is exactly the residual of the measurement. The methods hitherto used, for processing GEs, consider only the detectable component of the error, then as a consequence, may fail. In an attempt to overcome this limitation, and based on the works cited previously, were studied and implemented two alternative methodologies for process measurements with GEs. The first one is based on the direct analysis of the components of the errors of the measurements, the second one, in a similar way to the traditional methods, is based on the analysis of the measurements residuals. However, the differential of the second proposed methodology lies in the fact that it doesn\'t consider a fixed threshold value for detecting measurements with GEs. In this case, we adopted a new threshold value (TV ) characteristic of each measurement, as presented in the work of PIERETI (2011). Furthermore, in order to reinforce this theory, we propose an alternative way to calculate these thresholds, by analyzing the geometry of the probability density function of the multivariate normal distribution, relating to the measurements residuals.
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Estimação de estado: a interpretação geométrica aplicada ao processamento de erros grosseiros em medidas / Study of systems with optical orthogonal multicarrier and consistentCarvalho, Breno Elias Bretas de 22 March 2013 (has links)
Este trabalho foi proposto com o objetivo de implementar um programa computacional para estimar os estados (tensões complexas nodais) de um sistema elétrico de potência (SEP) e aplicar métodos alternativos para o processamento de erros grosseiros (EGs), baseados na interpretação geométrica dos erros e no conceito de inovação das medidas. Através da interpretação geométrica, BRETAS et al. (2009), BRETAS; PIERETI (2010), BRETAS; BRETAS; PIERETI (2011) e BRETAS et al. (2013) demonstraram matematicamente que o erro da medida se compõe de componentes detectáveis e não detectáveis, e ainda que a componente detectável do erro é exatamente o resíduo da medida. As metodologias até então utilizadas, para o processamento de EGs, consideram apenas a componente detectável do erro, e como consequência, podem falhar. Na tentativa de contornar essa limitação, e baseadas nos trabalhos citados previamente, foram estudadas e implementadas duas metodologias alternativas para processar as medidas portadoras de EGs. A primeira, é baseada na análise direta das componentes dos erros das medidas; a segunda, de forma similar às metodologias tradicionais, é baseada na análise dos resíduos das medidas. Entretanto, o diferencial da segunda metodologia proposta reside no fato de não considerarmos um valor limiar fixo para a detecção de medidas com EGs. Neste caso, adotamos um novo valor limiar (TV, do inglês: Threshold Value), característico de cada medida, como apresentado no trabalho de PIERETI (2011). Além disso, com o intuito de reforçar essa teoria, é proposta uma forma alternativa para o cálculo destes valores limiares, através da análise da geometria da função densidade de probabilidade da distribuição normal multivariável, referente aos resíduos das medidas. / This work was proposed with the objective of implementing a computer program to estimate the states (complex nodal voltages) in an electrical power system (EPS) and apply alternative methods for processing gross errors (GEs), based on the geometrical interpretation of the measurements errors and the innovation concept. Through the geometrical interpretation, BRETAS et al. (2009), BRETAS; PIERETI (2010), BRETAS; BRETAS; PIERETI (2011) and BRETAS et al. (2013) proved mathematically that the measurement error is composed of detectable and undetectable components, and also showed that the detectable component of the error is exactly the residual of the measurement. The methods hitherto used, for processing GEs, consider only the detectable component of the error, then as a consequence, may fail. In an attempt to overcome this limitation, and based on the works cited previously, were studied and implemented two alternative methodologies for process measurements with GEs. The first one is based on the direct analysis of the components of the errors of the measurements, the second one, in a similar way to the traditional methods, is based on the analysis of the measurements residuals. However, the differential of the second proposed methodology lies in the fact that it doesn\'t consider a fixed threshold value for detecting measurements with GEs. In this case, we adopted a new threshold value (TV ) characteristic of each measurement, as presented in the work of PIERETI (2011). Furthermore, in order to reinforce this theory, we propose an alternative way to calculate these thresholds, by analyzing the geometry of the probability density function of the multivariate normal distribution, relating to the measurements residuals.
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Characterizing the Low Net-to-Gross, Fluviodeltaic Dry Hollow Member of the Frontier Formation, Western Green River Basin, WyomingMeek, Scott Romney 01 August 2017 (has links)
The Frontier Formation in the Green River Basin of southwestern Wyoming consists of Late Cretaceous (Cenomanian-Turonian) marine and non-marine sandstones, siltstones, mudstones and coals deposited on the western margin of the Cretaceous Interior Seaway. Tight gas reservoirs exist in subsurface fluviodeltaic sandstones in the upper Frontier Formation (Dry Hollow Member) on the north-south trending Moxa Arch within the basin. These strata crop out in hogback ridges of the Utah-Idaho-Wyoming Thrust Belt approximately 40 km west of the crest of the Moxa Arch. Detailed, quantitative outcrop descriptions were constructed using emerging photogrammetric techniques along with field observations and measured sections at five key outcrop localities along the thrust belt. Understanding the architectural style of this low net-to-gross fluvial system allows for improved reservoir prediction in this and other comparable basins. The architectural style of the Dry Hollow Member fluvial deposits varies vertically as the result of a relative shoreline transgression during Dry Hollow deposition. Amalgamated conglomerates and associated fine to coarse sandstones near the base of the section and much thinner, isolated sandstones near the top of the Dry Hollow occur in laterally extensive units that can be identified over tens of kilometers. These units also provide means to relate outcrop and subsurface stratigraphic architecture. Combined with available subsurface data, fully-realized 3D static reservoir models for use as analogs in subsurface reservoir characterization may be constructed. Grain size, reservoir thickness and connectivity of fluvial sandstones is generally greatest near the base of this member and decreases upward overall. Despite relative isolation of some channel bodies, geocellular facies modeling indicates good lateral and vertical connectivity of most channel sandstones. The Kemmerer Coal Zone, with little sandstone, divides lower and upper well-connected sandy units.
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Aspects of analysis of small-sample right censored data using generalized Wilcoxon rank testsÖhman, Marie-Louise January 1994 (has links)
The estimated bias and variance of commonly applied and jackknife variance estimators and observed significance level and power of standardised generalized Wilcoxon linear rank sum test statistics and tests, respectively, of Gehan and Prentice are compared in a Monte Carlo simulation study. The variance estimators are the permutational-, the conditional permutational- and the jackknife variance estimators of the test statistic of Gehan, and the asymptotic- and the jackknife variance estimators of the test statistic of Prentice. In unbalanced small sample size problems with right censoring, the commonly applied variance estimators for the generalized Wilcoxon rank test statistics of Gehan and Prentice may be biased. In the simulation study it appears that variance properties and observed level and power may be improved by using the jackknife variance estimator. To establish the sensitivity to gross errors and misclassifications for standardised generalized Wilcoxon linear rank sum statistics in small samples with right censoring, the sensitivity curves of Tukey are used. For a certain combined sample, which might contain gross errors, a relatively simple method is needed to establish the applicability of the inference drawn from the selected rank test. One way is to use the change of decision point, which in this thesis is defined as the smallest proportion of altered positions resulting in an opposite decision. When little is known about the shape of a distribution function, non-parametric estimates for the location parameter are found by making use of censored one-sample- and two-sample rank statistics. Methods for constructing censored small sample confidence intervals and asymptotic confidence intervals for a location parameter are also considered. Generalisations of the solutions from uncensored one-sample and two-sample rank tests are utilised. A Monte-Carlo simulation study indicates that rank estimators may have smaller absolute estimated bias and smaller estimated mean squared error than a location estimator derived from the Product-Limit estimator of the survival distribution function. The ideas described and discussed are illustrated with data from a clinical trial of Head and Neck cancer. / digitalisering@umu
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Greenhouse gas emissions (CH4, CO2 and N2O) from a newly flooded hydroelectric reservoir in subtropical South Asia : The case of Nam Theun 2 Reservoir, Lao PDRDeshmukh, Chandrashekhar 28 March 2013 (has links) (PDF)
L'augmentation de l'intérêt concernant la part des réservoirs hydroélectrique dans l'augmentation de la concentration atmosphérique des Gaz à Effet de Serre (GES) a amené à mesurer les émissions nettes d'un réservoir hydroélectrique, Nam Theun 2 (NT2) dans la région subtropicale de la République Démocratique Populaire du Laos, Asie. Ce travail est la première évaluation de l'empreinte carbone des GES (c'est à dire : les émissions après ennoiement moins les émissions avant ennoiement) en relation avec la création d'un réservoir hydroélectrique. C'est le résultat d'une étude à grande échelle qui s'est déroulée pendant cinq ans (2008-2012). Nous avons tout d'abord quantifié les sources et les puits majeurs des GES des composants terrestres et aquatiques du paysage avant ennoiement (Mai 2008). Ensuite, à partir d'Avril 2009, cette étude similaire a été réalisée au niveau du réservoir, sa zone de marnage et son aval. C'est en Octobre 2009 que le réservoir hydroélectrique NT2 a, pour la première fois, atteint son niveau maximal et c'est huit mois plus tard, en Mars 2010, que les turbines ont fonctionnées pour la première fois. En se basant sur un suivi bimensuel et sur cinq missions de terrain couvrant toutes les saisons, les émissions des principaux GES (c'est à dire l'oxyde nitreux (N2O), le méthane (CH4) et le dioxyde de carbone (CO2)) ont été mesurées d'Avril 2009 à Décembre 2011. Les émissions ont été déterminées à la surface du réservoir (flux diffusifs et ébullitifs) ainsi que dans les sols de la zone de marnage, qui peut atteindre 370 km2 pour une surface totale de réservoir de 450 km2.
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Internal Nitrogen Cycling in Tropical Forest Soils / Bodeninterne Stickstoffkreisläufe in tropischen RegenwäldernArnold, Julia 10 December 2008 (has links)
No description available.
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Nitrogen response efficiency, nitrogen retention efficiency, and asymbiotic biological nitrogen fixation of a temperate permanent grassland site under different sward compositions and management practicesKeuter, Andreas 08 January 2013 (has links)
No description available.
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