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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.
381

Integrating XML and RDF concepts to achieve automation within a tactical knowledge management environment

McCarty, George E., Jr. 03 1900 (has links)
Approved for public release, distribution is unlimited / Since the advent of Naval Warfare, Tactical Knowledge Management (KM) has been critical to the success of the On Scene Commander. Today's Tactical Knowledge Manager typically operates in a high stressed environment with a multitude of knowledge sources including detailed sensor deployment plans, rules of engagement contingencies, and weapon delivery assignments. However the WarFighter has placed a heavy reliance on delivering this data with traditional messaging processes while focusing on information organization vice knowledge management. This information oriented paradigm results in a continuation of data overload due to the manual intervention of human resources. Focusing on the data archiving aspect of information management overlooks the advantages of computational processing while delaying the empowerment of the processor as an automated decision making tool. Resource Description Framework (RDF) and XML provide the potential of increased machine reasoning within a KM design allowing the WarFighter to migrate from the dependency on manual information systems to a more computational intensive Knowledge Management environment. However the unique environment of a tactical platform requires innovative solutions to automate the existing naval message architecture while improving the knowledge management process. This thesis captures the key aspects for building a prototype Knowledge Management Model and provides an implementation example for evaluation. The model developed for this analysis was instantiated to evaluate the use of RDF and XML technologies in the Knowledge Management domain. The goal for the prototype included: 1. Processing required technical links in RDF/XML for feeding the KM model from multiple information sources. 2. Experiment with the visualization of Knowledge Management processing vice traditional Information Resource Display techniques. The results from working with the prototype KM Model demonstrated the flexibility of processing all information data under an XML context. Furthermore the RDF attribute format provided a convenient structure for automated decision making based on multiple information sources. Additional research utilizing RDF/XML technologies will eventually enable the WarFighter to effectively make decisions under a Knowledge Management Environment. / Civilian, SPAWAR System Center San Diego
382

Inexpensive uncertainty analysis for CFD applications

Ghate, Devendra January 2014 (has links)
The work presented in this thesis aims to provide various tools to be used during design process to make maximum use of the increasing availability of accurate engine blade measurement data for high fidelity fluid mechanic simulations at a reasonable computational expense. A new method for uncertainty propagation for geometric error has been proposed for fluid mechanics codes using adjoint error correction. Inexpensive Monte Carlo (IMC) method targets small uncertainties and provides complete probability distribution for the objective function at a significantly reduced computational cost. A brief literature survey of the existing methods is followed by the formulation of IMC. An example algebraic model is used to demonstrate the IMC method. The IMC method is extended to fluid mechanic applications using Principal Component Analysis (PCA) for reduced order modelling. Implementation details for the IMC method are discussed using an example airfoil code. Finally, the IMC method has been implemented and validated for an industrial fluid mechanic code HYDRA. A consistent methodology has been developed for the automatic generation of the linear and adjoint codes by selective use of automatic differentiation (AD) technique. The method has the advantage of keeping the linear and the adjoint codes in-sync with the changes in the underlying nonlinear fluid mechanic solver. The use of various consistency checks have been demonstrated to ease the development and maintenance process of the linear and the adjoint codes. The use of AD has been extended for the calculation of the complete Hessian using forward-on-forward approach. The complete mathematical formulation for Hessian calculation using the linear and the adjoint solutions has been outlined for fluid mechanic solvers. An efficient implementation for the Hessian calculation is demonstrated using the airfoil code. A new application of the Independent Component Analysis (ICA) is proposed for manufacturing uncertainty source identification. The mathematical formulation is outlined followed by an example application of ICA for artificially generated uncertainty for the NACA0012 airfoil.
383

Zpětná vazba ve výuce češtiny jako cizího jazyka / Feedback in Czech Language Courses for Foreigners

Plísková, Kamila January 2015 (has links)
This thesis explores teacher's feedback, its definition, types, and is specifically focused on feedback moves in context of teaching Czech as a foreign language. The aim of this thesis is to present current research on the feedback in the context of teaching a second/foreign language and describe how the feedback is used in Czech language courses for foreigners and what instruments teachers use for such purpose. The first part is focusing on the feedback as part of the educational dialogue and communication in the language classroom; introducing some concepts and hypotheses of second language acquisition in which feedback figures. We also provide a description of feedback, both positive and corrective, and we present current studies concerning feedback within language learning. The empirical part carries out conversational analysis of transcribed recordings of participant observation in Czech courses for foreigners, in which we focus on feedback moves of lecturers. The thesis includes glossary explaining relevant terms translated into Czech. Key words: Feedback, positive feedback, corrective feedback, communication in the language classroom, error correction, Czech for foreigners, conversation analysis
384

Monetární transmisní mechanizmus: pohled do černé skříňky / Monetary Transmission Mechanism: A Closer Look Inside the Black Box

Dvořák, Martin January 2014 (has links)
The recent economic and financial turmoil has led central banks around the world to heavily utilize unconventional monetary policy measures. Unconventional in this sense means a deflection from traditional central bank policy measures, i.e. interest rate innovations. Although these measures were widely discussed, the uniformed, coherent and comprehensive framework of such measures is still missing. The aim of this thesis is to establish the framework for possible classification of such policies together with transmission channels to the real economy. The empirical part examines the impacts of unconventional policies on real data using vector autoregression and vector error correction models. This analysis is based on monthly data period between 1999 and 2013, which is strongly affected by implementation of the unconventional policies in its second half. The last section examines the possible future of these policies as a normal instrument of central banks and describes their main challenges and shortcomings. JEL classification: C32, E40, E44, E50, E52, E58, E60 Keywords: Unconventional monetary policy, Interest rate, Decoupling principle, Balance sheet policy stratification, Quantitative easing, Channels of transmission, Vector Autoregression, Vector error correction model Author's e-mail:...
385

Makro-fundamentální analýza CEE & SEE trhů / CEE & SEE Markets Macro-Fundamental Analysis

Poštulková, Jitka January 2016 (has links)
The aim of this thesis is to verify and analyse presumed relations between selected macro-fundamentals, namely USD exchange rate, production index, interbank offered rate, inflation, money supply and two exogenous indices ( Standard & Poor's 500 and EURO STOXX 50), and CEE (Austria, Czech Republic, Poland, Hungary) or SEE (Bulgaria, Croatia, Slovenia, Romania) financial markets over the period from December 1995 to December 2015. In order to test the long-run cointegration relationships between studied markets and the set of macroeconomic variables, the Engle-Granger and Johansen tests are applied. The vector error correction model is used to confirm the long-run equilibrium interlinkages and the results show similar trend tendencies between stock indices and some of the macro-fundamentals in Croatia, Czech Republic, Hungary, Poland and Romania. To verify the short-run causal linkages, the Granger causality test is employed. Based on retrieved findings, the efficiency of studied markets with respect to Efficient Market Theory is reviewed. Our findings reveal several pairwise short-run causal impacts between studied macroeconomic indicators and stock indices. The only indicator which does not impact any stock market is the interbank offered rate. Moreover, according to our results, all CEE&SEE stock...
386

Equações de oferta e demanda por exportações do Brasil: um estudo comparativo do setor de madeira e móveis

Mazzotti, Argos Unildo 01 August 2008 (has links)
Made available in DSpace on 2015-03-05T18:57:20Z (GMT). No. of bitstreams: 0 Previous issue date: 1 / Nenhuma / Esta dissertação trata da estimação das equações de exportação para o total da economia brasileira e para o setor madeira e mobiliário do Brasil, a partir de dados trimestrais, no período entre 1985 e 2006. Os procedimentos econométricos utilizam o conceito de co-integração de Johansen associado a um modelo de correção de erros. É dada especial atenção a um possível problema de instabilidade dos parâmetros resultante, principalmente, do impacto da abertura comercial no início do período, das mudanças associadas ao Plano Real e da elevação nos preços de exportação no final do período. Um dos aspectos mais interessantes, relacionado com a abertura comercial brasileira, está presente na demanda por exportações onde a renda externa passa a ter uma importância relativa muito maior ao longo do período quando comparada ao câmbio. Esta mudança está presente no âmbito do setor madeira e mobiliário, mas também é destaque no agregado. Outro resultado importante, agora no lado da oferta por exportações, mostra a relação / This dissertation is about the estimation of export equations for both Brazilian total economy and Brazilian wood-furniture sector, using quarterly data, from 1985 to 2006. The econometric procedures use the Johansen’s co-integration concept associated to an error-correction model. Special attention is dedicated to a possible problem of instability in parameters resulting, mainly, from the impact of the opening trade in the beginning of the period, from changes associated to the Real Plan and from the raise of the export prices in the end of the period. One of the most interesting aspects, related to the Brazilian trade opening, occurs in the export demand where the foreign income starts to have relatively higher importance along the period when compared to the exchange rate. This change is present in the ambit of the wood-furniture sector, but it also stands out for the aggregate. Another important result, now related to export supply, shows the relation of significance between the main sources of exporter
387

Prise en compte des erreurs de mesure dans l’analyse du risque associe a l’exposition aux rayonnements ionisants dans une cohorte professionnelle : application à la cohorte française des mineurs d'uranium / Taking into account measurement error in the analysis of risk associated with exposure to ionizing radiation in an occupational cohort : application to the French cohort of uranium miners.

Allodji, Setcheou Rodrigue 09 December 2011 (has links)
Dans les études épidémiologiques, les erreurs de mesure de l’exposition étudiée peuvent biaiser l’estimation des risques liés à cette exposition. Un grand nombre de méthodes de correction de l’effet de ces erreurs a été développé mais en pratique elles ont été rarement appliquées, probablement à cause du fait que leur capacité de correction et leur mise en œuvre sont peu maîtrisées. Une autre raison non moins importante est que, en l’absence de données répétées ou de données de validation, ces méthodes de correction exigent la connaissance détaillée des caractéristiques (taille, nature, structure et distribution) des erreurs de mesure. L’objectif principal de cette thèse est d’étudier l’impact de la prise en compte des erreurs de mesure dans les analyses du risque de décès par cancer du poumon associé à l’exposition au radon à partir de la cohorte française des mineurs d’uranium (qui ne dispose ni de données répétées, ni de données de validation). Les objectifs spécifiques étaient (1) de caractériser les erreurs de mesure associées aux expositions radiologiques (radon et ses descendants, poussières d’uranium et rayonnements gamma), (2) d’étudier l’impact des erreurs de mesure de l’exposition au radon et à ses descendants sur l’estimation de l’excès de risque relatif (ERR) de décès par cancer du poumon et (3) d’étudier et comparer la performance des méthodes de correction de l’effet de ces erreurs. La cohorte française des mineurs d’uranium comprend plus de 5000 individus exposés de manière chronique au radon et à ses descendants qui ont été suivis en moyenne pendant 30 ans. Les erreurs de mesure ont été caractérisées en prenant en compte l’évolution des méthodes d’extraction et de la surveillance radiologique des mineurs au fil du temps. Une étude de simulation basée sur la cohorte française des mineurs d’uranium a été mise en place pour étudier l’impact de ces erreurs sur l’ERR ainsi que pour comparer la performance des méthodes de correction. Les résultats montrent que les erreurs de mesure de l’exposition au radon et à ses descendants ont diminué au fil des années. Pour les premières années, avant 1970, elles dépassaient 45 % et après 1980 elles étaient de l’ordre de 10 %. La nature de ces erreurs a aussi changé au cours du temps ; les erreurs essentiellement de nature Berkson ont fait place à des erreurs de nature classique après la mise en place des dosimètres individuels à partir de 1983. Les résultats de l’étude de simulation ont montré que les erreurs de mesure conduisent à une atténuation de l’ERR vers la valeur nulle, avec un biais important de l’ordre de 60 %. Les trois méthodes de correction d’erreurs considérées ont permis une réduction notable mais partielle du biais d’atténuation. Un avantage semble exister pour la méthode de simulation extrapolation (SIMEX) dans notre contexte, cependant, les performances des trois méthodes de correction sont fortement tributaires de la détermination précise des caractéristiques des erreurs de mesure.Ce travail illustre l’importance de l’effet des erreurs de mesure sur les estimations de la relation entre l’exposition au radon et le risque de décès par cancer du poumon. L’obtention d’estimation de risque pour laquelle l’effet des erreurs de mesure est corrigé devrait s’avérer d’un intérêt majeur en support des politiques de protection contre le radon en radioprotection et en santé publique. / In epidemiological studies, measurement errors in exposure can substantially bias the estimation of the risk associated to exposure. A broad variety of methods for measurement error correction has been developed, but they have been rarely applied in practice, probably because their ability to correct measurement error effects and their implementation are poorly understood. Another important reason is that many of the proposed correction methods require to know measurement errors characteristics (size, nature, structure and distribution).The aim of this thesis is to take into account measurement error in the analysis of risk of lung cancer death associated to radon exposure based on the French cohort of uranium miners. The mains stages were (1) to assess the characteristics (size, nature, structure and distribution) of measurement error in the French uranium miners cohort, (2) to investigate the impact of measurement error in radon exposure on the estimated excess relative risk (ERR) of lung cancer death associated to radon exposure, and (3) to compare the performance of methods for correction of these measurement error effects.The French cohort of uranium miners includes more than 5000 miners chronically exposed to radon with a follow-up duration of 30 years. Measurement errors have been characterized taking into account the evolution of uranium extraction methods and of radiation protection measures over time. A simulation study based on the French cohort of uranium miners has been carried out to investigate the effects of these measurement errors on the estimated ERR and to assess the performance of different methods for correcting these effects.Measurement error associated to radon exposure decreased over time, from more than 45% in the early 70’s to about 10% in the late 80’s. Its nature also changed over time from mostly Berkson to classical type from 1983. Simulation results showed that measurement error leads to an attenuation of the ERR towards the null, with substantial bias on ERR estimates in the order of 60%. All three error-correction methods allowed a noticeable but partial reduction of the attenuation bias. An advantage was observed for the simulation-extrapolation method (SIMEX) in our context, but the performance of the three correction methods highly depended on the accurate determination of the characteristics of measurement error.This work illustrates the importance of measurement error correction in order to obtain reliable estimates of the exposure-risk relationship between radon and lung cancer. Corrected risk estimates should prove of great interest in the elaboration of protection policies against radon in radioprotection and in public health.
388

The determinants of government expenditure in South Africa

Maluleke, Glenda 11 1900 (has links)
This study empirically examines the determinants of government expenditure in South Africa using annual data for the period from 1970 to 2014; and provides an overview of the South African government expenditure. The Johansen-Juselius co-integration test established that there is a long-run relationship between government expenditure and its determinants. The error correction model was used to examine the key determinants. The results of this study show that urbanisation rate, national income, poverty reduction; trade openness lagged one period and the wage rate significantly influence the size of government expenditure. Therefore, the study recommend that government create job opportunities; increase its expenditure in developing rural areas; and find ways to manage the public sector wage bill. The study concludes that population growth, inflation and trade openness in current period are not important in determining government expenditure in South Africa / Economics / M. Com. (Economics)
389

Elasticidade-PIB do Imposto de Renda Pessoa Física e Jurídica / Elasticity of income tax revenue for individuals and corporations

Leonardo Ribeiro de Freitas 03 December 2012 (has links)
O objetivo específico da presente dissertação é estimar a elasticidade-PIB do Imposto de Renda Pessoa Física (IRPF) e Imposto Renda Pessoa Jurídica (IRPJ) no Brasil entre 1986 e 2012. A pesquisa também incorpora em seus objetivos uma análise técnica a respeito da tributação e seus impactos sobre o sistema econômico, tanto a nível microeconômico e macroeconômico, além de abordar o IRPF e IRPJ em seu aspecto econômico e jurídico. No tratamento metodológico são utilizados modelos de Vetor de Correção de erros (VEC) para estimar as elasticidades-PIB do IRPF e IRPJ. Os resultados apontam uma elasticidade-PIB, tanto para IRPF quanto IRPJ, acima da unidade, na maioria dos modelos estimados, e existem períodos determinados que impactam consideravelmente sobre à arrecadação desses tributos. / This dissertation estimates the GDP elasticity of income tax revenue for individuals (IRPF) and corporations (IRPJ) between 1986 and 2012. Additionally the research incorporates an analysis of the macroeconomic and microeconomic effects of taxation. IRPF and IRPJ are analyzed in great detail, including economic as well as legal aspects. An Error Correction Model is estimated to obtain the elasticities. The results show that both elasticities are higher than unit and that reforms that took place in some periods have a significant impact on tax collection.
390

Modelo de cointegração variando com o tempo: abordagem via ondaletas / Time varying cointegration model: approach using wavelets

Eder Lucio da Fonseca 06 March 2017 (has links)
Duas ou mais séries não estacionárias são cointegradas se existir uma relação de equilíbrio de longo prazo entre elas. Nas últimas décadas, o interesse na literatura sobre o tema cointegração aumentou de maneira expressiva. Os modelos tradicionais supõem que o vetor de cointegração não varia ao longo do tempo. Entretanto, existem evidências na literatura de que esta suposição pode ser considerada muito restritiva. Utilizando o conceito de ondaletas, propomos um modelo de correção de erros vetorial em que é permitido ao vetor de cointegração variar ao longo do tempo. Diferente de trabalhos similares, é permitido ao vetor de cointegração variar suave ou abruptamente, dependendo da família de ondaletas considerada. Experimentos de Monte Carlo foram utilizados para estudar os quantis e o poder do teste de razão de verossimilhanças entre as hipóteses de cointegração usual e a de cointegração variando com o tempo. Os experimentos sugerem que o teste possui poder contra alternativas que variam ao longo do tempo. Foi demonstrada a capacidade do modelo em lidar satisfatoriamente com séries cointegradas simuladas, que apresentavam mudança de regime para o vetor de cointegração. O modelo foi empregado ainda para testar a validade da hipótese de paridade de poder de compra entre Estados Unidos e doze países da Organização para Cooperação e Desenvolvimento Econômico (OECD): Canadá, Japão e mais dez países europeus. Assim como em trabalhos similares, foram verificadas evidências de cointegração variando com o tempo entre os países. Foram utilizados valores-p bootstrap para verificar a significância da estatística do teste. / Two or more non-stationary time series are cointegrated if there is a long-run equilibrium relationship between them. In recent decades, interest in the literature on the subject of cointegration increased expressively. Traditional models that address this issue assume that the cointegration vector does not vary over time. However, there is evidence in the literature that this assumption can be considered very restrictive. Using the concept of wavelets, we propose a vector error correction model in which is allowed to the cointegration vector vary over time. Unlike similar works, the cointegration vector is allowed to vary smoothly or abruptly, depending on the considered family of wavelets. Monte Carlo experiments were used to study the quantiles and the power of the likelihood ratio test of the hypotheses of usual cointegration versus the time-varying cointegration. The experiments suggest that the test has power against alternatives that vary over time. It was demonstrated the ability of the model to deal satisfactorily with simulated cointegrated series, which presented regime change for the cointegration vector. The model was also used to test the validity of the Purchasing Power Parity hypothesis between United States and twelve countries of the Organization for Economic Cooperation and Development (OECD): Canada, Japan and ten other European countries. As in similar works, evidence of time-varying cointegration was verified among countries. Bootstrap p-values were used to verify the significance of the likelihood ratio of the test.

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