No description available.

O objetivo primordial deste trabalho é analisar se a democracia é uma instituição política que produz resultados econômicos menos desiguais do que os regimes autoritários. A importância deste tema reside no fato que a própria promoção da democracia na agenda da política internacional tornou-se fundamental por inúmeras razões entre as quais sua suposta propensão em reduzir estas disparidades econômicas. Em primeiro lugar apresentamos no Capítulo 1 um balanço da discussão teórica e empírica a partir da qual constatamos que, a despeito do senso comum de que a democracia está relacionada a uma cidadania mais igualitária, os seus efeitos sobre a desigualdade ainda são discutíveis. Mesmo existindo um razoável consenso teórico de que os regimes democráticos devem, de alguma forma, produzir uma melhor distribuição de bens, os resultados empíricos são inconclusivos e contraditórios. Em seguida, diante de tal impasse empírico, propomos no Capítulo 2 uma reformulação da argumentação na qual entendemos que os efeitos da democracia sobre a desigualdade devem ser reinterpretados. A principal contribuição da tese reside na constatação, tanto teórica quanto empírica, de que estes efeitos são heterogêneos e interagem com o próprio nível de desigualdade, e, por conseguinte, é equivocado o suposto de que esses efeitos são homogêneos e independentes do contexto sócio-econômico da desigualdade. No Capítulo 3 apresentamos os dados e os conceitos de democracia e desigualdade. Assumimos que democracia se caracteriza como o regime político no qual os líderes competem entre si por meio de eleições e verificamos se os seus efeitos variam ao longo da própria distribuição de desigualdade econômica mensurada pelo coeficiente de GINI. Para tal análise, realizamos uma série de modelos de regressão quantílica, a metodologia adequada para avaliar o debate sobre a heterogeneidade versus homogeneidade dos efeitos. O argumento teórico, a partir do qual elabora-se a hipótese dos efeitos heterogêneos, refere-se à necessidade de uma convergência entre os interesses eleitorais dos partidos o lado da oferta e as clivagens sobre as quais uma potencial maioria dos eleitores tem interesse em ser atendido o lado da demanda por políticas públicas e plataformas. Isto posto, é 9 necessário discutir as condições que estimulam as lideranças políticas a utilizarem o problema da desigualdade econômica como argumento eleitoral e as condições nas quais surge uma demanda dos cidadãos por redistribuição via ação estatal. Somente nas sociedades mais desiguais tanto os partidos políticos têm interesse em ofertar políticas redistributivas, quanto tende a surgir no seio da cidadania uma demanda por redistribuição por parte de uma maioria de eleitores. No Capítulo 4 comprovamos empiricamente que os efeitos da competição democrática em sociedades mais desiguais são diferentes seus efeitos em sociedades mais iguais; e estes efeitos estão em direção à maior redução da desigualdade apenas nas sociedades mais desiguais. Os resultados são robustos às mais diferentes especificações dos modelos estatísticos, dados e formas de mensuração, tanto de democracia quanto de desigualdade, em diferentes cortes temporais e horizontes históricos de análise. Inclusive quando estendemos o recorte temporal para antes do pós-2ª Guerra Mundial utilizando dados que abrangem o período de surgimento dos primeiros regimes representativos democráticos no século XIX, a veracidade das hipóteses dos efeitos heterogêneos e de que há maior contundência da democracia em direção à redução da desigualdade nas sociedades mais desiguais permanece. Por fim, além deste problema teórico e empírico de crucial importância, também controlamos a análise para a potencial relação recíproca entre democracia e desigualdade. Enquanto parte da literatura discute os potenciais efeitos igualitários da democracia, outra importante literatura debate se o aumento da desigualdade aumenta ou reduz a probabilidade de um país tornar-se ou manter-se democrático. Posto isto, apresentamos uma lista de variáveis instrumentais para estimar validamente os efeitos da democracia sobre a desigualdade independente da relação entre desigualdade e democracia / The primary aim of this study is to analyze whether democracy is a political institution that produces less unequal economic outcomes than authoritarian regimes. The importance of this issue lies in the fact that the very promotion of democracy in the international political agenda has become essential for many reasons, including its supposed propensity to reduce economic disparities. First, at Chapter 1 we overview the theoretical and empirical discussion from which we find that despite the common sense that democracy must be related to a more egalitarian citizenship, its effects on inequality is still debatable. Even with a reasonable theoretical consensus that democracies must somehow produce a better distribution of goods; the empirical results are inconclusive and contradictory. After that, facing such empirical impasse, we propose at Chapter 2 a reformulation about the rationale to explain and analyze the effects of democracy on inequality. The main contribution of this thesis lies in both the theoretical and the empirical claim that these effects are heterogeneous and should interact with the level of inequality and, therefore, the assumption that these effects are homogeneous and independent of the socio-economic context of inequality is wrong. In Chapter 3, we present the data and concepts of democracy and inequality. We assume that democracy is characterized as a political regime in which leaders compete through elections and we test whether the effects vary along the distribution of economic inequality measured by the Gini coefficient. To do that, we conducted a series of quantile regression models, appropriate to evaluate the alternative hypothesis whether the effects are heterogeneous or homogenous. The theoretical argument, from which we elaborate the hypothesis of heterogeneous effects, refers to the need for a convergence between the electoral interests of the parties - the supply side - and the political cleavages on which a majority of voters have potential interest being played - the demand side for other public policies and platforms. Hence, it is necessary to discuss the conditions that lead the political leadership to use the problem of economic 11 inequality as an electoral argument and the conditions under which a demand by citizens for redistribution via state action rises. Only at the most unequal societies the political parties have an interest in offering redistributive policies, as well as there is a higher propensity for a redistribution demand by a majority of voters. In Chapter 4, we proved empirically that the effects of democratic competition at more unequal societies are different from the effects of democracy in more equal societies; and these effects tend to be greater toward inequality reduction only at more unequal societies. These results are robust to different statistical model specifications, data and measurement methods, about both democracy and inequality, and to the use of different time horizons. Even when we extend the time frame of the analysis to the period before World War II - using new data that covers XIX century, the veracity of the hypotheses about the heterogeneous effects and that these effects of democracy toward the reduction of inequality are larger at the most unequal societies remains intact. Finally, beyond this theoretical and empirical issue of crucial importance, we also control the analysis for potential reciprocal relationship between democracy and inequality. This is because while much of the literature discusses the potential effects of egalitarian democracy, another important literature debate discusses whether greater inequality increases or reduces the probability of a country become or remain democratic. Hence, we present a list of valid instrumental variables to estimate the effects of democracy on inequality independent of the relationship between inequality and democracy

近年來，全球氣候變遷問題已嚴重影響人類生活，而世界各國也逐漸意識到已開發國家和開發中國家必須共同合作以解決此問題。京都議定書中的清潔發展機制 (CDM) 即是讓已開發國家與開發中國家共同實踐減量目標的一種彈性減量機制，然而過去文獻對於其減排成效的看法並不一致。有鑒於此，本文以參與CDM計畫的20個開發中國家和16個已開發國家為研究對象，探討CDM計畫對其2003至2008年二氧化碳減量之影響。根據兩階段最小平方法之固定效果模型的實證結果顯示，CDM計畫能減少開發中國家的二氧化碳排放量，但經認證的排放減量額度 (CERs) 有被過量核發之現象；另一方面，CDM計畫對已開發國家的減排效果則無影響。 / In recent years, global climate change problem has affected humans’ life badly. Therefore, it is gradually realized that the developed countries and developing countries have to cooperate to solve the problem. Clean Development Mechanism (CDM) is one of the flexibility mechanisms defined in the Kyoto Protocol, and it allows the developed countries, in cooperation with developing countries, to fulfill the emission-reduction targets. However, the emissions abatement effects of CDM in the literatures are diverse. Accordingly, this paper uses 20 developed countries and 16 developing countries as an empirical case to examine the impact of CDM on carbon dioxide emissions abatement from 2003 to 2008. According to fixed effects two-stage least squares, CDM projects reduced the carbon dioxide emissions of developing countries, but the certified emissions reductions (CERs) were excessively issued. On the other hand, CDM projects didn’t have an impact of emissions abatement on developed countries.

O objetivo primordial deste trabalho é analisar se a democracia é uma instituição política que produz resultados econômicos menos desiguais do que os regimes autoritários. A importância deste tema reside no fato que a própria promoção da democracia na agenda da política internacional tornou-se fundamental por inúmeras razões entre as quais sua suposta propensão em reduzir estas disparidades econômicas. Em primeiro lugar apresentamos no Capítulo 1 um balanço da discussão teórica e empírica a partir da qual constatamos que, a despeito do senso comum de que a democracia está relacionada a uma cidadania mais igualitária, os seus efeitos sobre a desigualdade ainda são discutíveis. Mesmo existindo um razoável consenso teórico de que os regimes democráticos devem, de alguma forma, produzir uma melhor distribuição de bens, os resultados empíricos são inconclusivos e contraditórios. Em seguida, diante de tal impasse empírico, propomos no Capítulo 2 uma reformulação da argumentação na qual entendemos que os efeitos da democracia sobre a desigualdade devem ser reinterpretados. A principal contribuição da tese reside na constatação, tanto teórica quanto empírica, de que estes efeitos são heterogêneos e interagem com o próprio nível de desigualdade, e, por conseguinte, é equivocado o suposto de que esses efeitos são homogêneos e independentes do contexto sócio-econômico da desigualdade. No Capítulo 3 apresentamos os dados e os conceitos de democracia e desigualdade. Assumimos que democracia se caracteriza como o regime político no qual os líderes competem entre si por meio de eleições e verificamos se os seus efeitos variam ao longo da própria distribuição de desigualdade econômica mensurada pelo coeficiente de GINI. Para tal análise, realizamos uma série de modelos de regressão quantílica, a metodologia adequada para avaliar o debate sobre a heterogeneidade versus homogeneidade dos efeitos. O argumento teórico, a partir do qual elabora-se a hipótese dos efeitos heterogêneos, refere-se à necessidade de uma convergência entre os interesses eleitorais dos partidos o lado da oferta e as clivagens sobre as quais uma potencial maioria dos eleitores tem interesse em ser atendido o lado da demanda por políticas públicas e plataformas. Isto posto, é 9 necessário discutir as condições que estimulam as lideranças políticas a utilizarem o problema da desigualdade econômica como argumento eleitoral e as condições nas quais surge uma demanda dos cidadãos por redistribuição via ação estatal. Somente nas sociedades mais desiguais tanto os partidos políticos têm interesse em ofertar políticas redistributivas, quanto tende a surgir no seio da cidadania uma demanda por redistribuição por parte de uma maioria de eleitores. No Capítulo 4 comprovamos empiricamente que os efeitos da competição democrática em sociedades mais desiguais são diferentes seus efeitos em sociedades mais iguais; e estes efeitos estão em direção à maior redução da desigualdade apenas nas sociedades mais desiguais. Os resultados são robustos às mais diferentes especificações dos modelos estatísticos, dados e formas de mensuração, tanto de democracia quanto de desigualdade, em diferentes cortes temporais e horizontes históricos de análise. Inclusive quando estendemos o recorte temporal para antes do pós-2ª Guerra Mundial utilizando dados que abrangem o período de surgimento dos primeiros regimes representativos democráticos no século XIX, a veracidade das hipóteses dos efeitos heterogêneos e de que há maior contundência da democracia em direção à redução da desigualdade nas sociedades mais desiguais permanece. Por fim, além deste problema teórico e empírico de crucial importância, também controlamos a análise para a potencial relação recíproca entre democracia e desigualdade. Enquanto parte da literatura discute os potenciais efeitos igualitários da democracia, outra importante literatura debate se o aumento da desigualdade aumenta ou reduz a probabilidade de um país tornar-se ou manter-se democrático. Posto isto, apresentamos uma lista de variáveis instrumentais para estimar validamente os efeitos da democracia sobre a desigualdade independente da relação entre desigualdade e democracia / The primary aim of this study is to analyze whether democracy is a political institution that produces less unequal economic outcomes than authoritarian regimes. The importance of this issue lies in the fact that the very promotion of democracy in the international political agenda has become essential for many reasons, including its supposed propensity to reduce economic disparities. First, at Chapter 1 we overview the theoretical and empirical discussion from which we find that despite the common sense that democracy must be related to a more egalitarian citizenship, its effects on inequality is still debatable. Even with a reasonable theoretical consensus that democracies must somehow produce a better distribution of goods; the empirical results are inconclusive and contradictory. After that, facing such empirical impasse, we propose at Chapter 2 a reformulation about the rationale to explain and analyze the effects of democracy on inequality. The main contribution of this thesis lies in both the theoretical and the empirical claim that these effects are heterogeneous and should interact with the level of inequality and, therefore, the assumption that these effects are homogeneous and independent of the socio-economic context of inequality is wrong. In Chapter 3, we present the data and concepts of democracy and inequality. We assume that democracy is characterized as a political regime in which leaders compete through elections and we test whether the effects vary along the distribution of economic inequality measured by the Gini coefficient. To do that, we conducted a series of quantile regression models, appropriate to evaluate the alternative hypothesis whether the effects are heterogeneous or homogenous. The theoretical argument, from which we elaborate the hypothesis of heterogeneous effects, refers to the need for a convergence between the electoral interests of the parties - the supply side - and the political cleavages on which a majority of voters have potential interest being played - the demand side for other public policies and platforms. Hence, it is necessary to discuss the conditions that lead the political leadership to use the problem of economic 11 inequality as an electoral argument and the conditions under which a demand by citizens for redistribution via state action rises. Only at the most unequal societies the political parties have an interest in offering redistributive policies, as well as there is a higher propensity for a redistribution demand by a majority of voters. In Chapter 4, we proved empirically that the effects of democratic competition at more unequal societies are different from the effects of democracy in more equal societies; and these effects tend to be greater toward inequality reduction only at more unequal societies. These results are robust to different statistical model specifications, data and measurement methods, about both democracy and inequality, and to the use of different time horizons. Even when we extend the time frame of the analysis to the period before World War II - using new data that covers XIX century, the veracity of the hypotheses about the heterogeneous effects and that these effects of democracy toward the reduction of inequality are larger at the most unequal societies remains intact. Finally, beyond this theoretical and empirical issue of crucial importance, we also control the analysis for potential reciprocal relationship between democracy and inequality. This is because while much of the literature discusses the potential effects of egalitarian democracy, another important literature debate discusses whether greater inequality increases or reduces the probability of a country become or remain democratic. Hence, we present a list of valid instrumental variables to estimate the effects of democracy on inequality independent of the relationship between inequality and democracy

Submitted by Lucas Pimentel Vilela (lvilela@fgvmail.br) on 2013-10-07T17:22:14Z No. of bitstreams: 2 Dissertação Final.pdf: 665295 bytes, checksum: b54a14202e41e19e863a73328cfb2123 (MD5) Supplement.pdf: 2259071 bytes, checksum: 19718d483c50f35f3878c81521b0acf9 (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2013-10-08T21:33:30Z (GMT) No. of bitstreams: 2 Dissertação Final.pdf: 665295 bytes, checksum: b54a14202e41e19e863a73328cfb2123 (MD5) Supplement.pdf: 2259071 bytes, checksum: 19718d483c50f35f3878c81521b0acf9 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2013-10-14T14:44:28Z (GMT) No. of bitstreams: 2 Dissertação Final.pdf: 665295 bytes, checksum: b54a14202e41e19e863a73328cfb2123 (MD5) Supplement.pdf: 2259071 bytes, checksum: 19718d483c50f35f3878c81521b0acf9 (MD5) / Made available in DSpace on 2013-10-14T14:45:02Z (GMT). No. of bitstreams: 2 Dissertação Final.pdf: 665295 bytes, checksum: b54a14202e41e19e863a73328cfb2123 (MD5) Supplement.pdf: 2259071 bytes, checksum: 19718d483c50f35f3878c81521b0acf9 (MD5) Previous issue date: 2013-09-17 / This dissertation deals with the problem of making inference when there is weak identification in models of instrumental variables regression. More specifically we are interested in one-sided hypothesis testing for the coefficient of the endogenous variable when the instruments are weak. The focus is on the conditional tests based on likelihood ratio, score and Wald statistics. Theoretical and numerical work shows that the conditional t-test based on the two-stage least square (2SLS) estimator performs well even when instruments are weakly correlated with the endogenous variable. The conditional approach correct uniformly its size and when the population F-statistic is as small as two, its power is near the power envelopes for similar and non-similar tests. This finding is surprising considering the bad performance of the two-sided conditional t-tests found in Andrews, Moreira and Stock (2007). Given this counter intuitive result, we propose novel two-sided t-tests which are approximately unbiased and can perform as well as the conditional likelihood ratio (CLR) test of Moreira (2003). / Esta dissertação trata do problema de inferência na presença de identificação fraca em modelos de regresso com variáveis instrumentais. Mais especificamente em testes de hipóteses com relação ao parâmetro da variável endógena quando os instrumentos são fracos. O principal foco é nos testes condicionais unilaterais baseados nas estatísticas de razão de máxima verossimilhança, score e Wald. Resultados teóricos e numéricos mostram que o teste t condicional unilateral baseado no estimador de mínimos quadrados em dois estágios tem uma boa performance mesmo na presença de instrumentos fracamente correlacionados com a variável endógena. A abordagem condicional corrige uniformemente o tamanho do teste t e quando a estatística F populacional é tão pequena quanto dois, o poder do teste é próximo ao power envelope tanto de testes similares quanto de não similares. Tal resultado é surpreendente visto a má performance dos testes t’s condicionais bilaterais relatada em (6, Andrews, Moreira and Stock (2007)). Dado esse resultado aparentemente contra intuitivo, apresentamos novos testes t’s condicionals bilaterais que são aproximadamente não viesados e performam, em alguns casos, tão bem quanto o teste condicional baseado na estatística de razão de verossimilhança de ( 19 , Moreira (2003)).

Les études menées permettent de prendre en main un système depuis l’identification jusqu’à la commande robuste des systèmes non entiers. Les principes de la platitude permettent de parvenir à la planification de trajectoire à condition de connaître le modèle du système, d’où l’intérêt de l’identification des paramètres du système. Les principaux travaux de cette thèse concernent l’identification de système par modèles non entiers, la génération et la poursuite robuste de trajectoire par l’application des principes de la platitude aux systèmes non entiers.Le chapitre 1 rappelle les définitions et propriétés de l’opérateur non entier ainsi que les diverses méthodes de représentation d’un système non entier. Le théorème de stabilité est également remémoré. Les algèbres sur les polynômes non entiers et sur les matrices polynômiales non entières sont introduites pour l’extension de la platitude aux systèmes non entiers.Le chapitre 2 porte sur l’identification par modèle non entier. Après un état de l’art sur les méthodes d’identification par modèle non entier, deux contextes sont étudiés : en présence de bruit blanc et en présence de bruit coloré. Dans chaque cas, deux estimateurs optimaux (sur la variance et le biais) sont propos´es : l’un, en supposant une structure du modèle connue et d’ordres de dérivation fixés, et l’autre en combinant des techniques de programmation non linéaire qui optimise à la fois les coefficients et les ordres de dérivation.Le chapitre 3 établit l’extension des principes de la platitude aux systèmes non entiers.La platitude des systèmes non entiers linéaires en proposant différentes approches telles que les fonctions de transfert et la pseudo-représentation d’état par matrices polynômiales est étudiée.La robustesse du suivi de trajectoire est abordée par la commande CRONE. Des exemples de simulations illustrent les développements théoriques de la platitude au travers de la diffusion thermique sur un barreau métallique.Enfin, le chapitre 4 est consacré à la validation des contributions en identification, en planification de trajectoire et en poursuite robuste sur un système non entier réel : un barreau métallique est soumis à un flux de chaleur. / The general theme of the work enables to handle a system, from identification to robust control. Flatness principles tackle path planning unless knowing the system model, hence the system parameter identification necessity. The principal contribution of this thesis deal with system identification by non integer models and with robust path tracking by the use of flatness principles for fractional models.Chapter 1 recalls the definitions and properties of a fractional operator and also the various representation methods of a fractional system. The stability theorem is also brought to mind. Fractional polynomial and fractional polynomial matrice algebras are introduced for the extension of flatness principles for fractional systems.Chapter 2 is about non integer model identification. After a state of the art on system identification by non integer model. Two contexts are considered : in presence of white noise and of colored noise. In each situation, two optimal (in variance and bias sense) estimators are put forward : one, when considering a known model structure with fixed differentiating orders, and another one by combining nonlinear programming technics for the optimization of coefficients and differentiating orders.Chapter 3 establishes the extension of flatness principles to fractional systems. Flatness of linear fractional systems are studied while considering different approaches such as transfer functions or pseudo-state-space representations with polynomial matrices. Path tracking robustness is ensured with CRONE control. Simulation examples display theoretical developments on flatness through thermal diffusion on a metallic rod. Finally, Chapter 4 is devoted to validate the contributions to system identification, to trajectory planning and to robust path tracking on a real fractional system : a metallic rod submitted to a heat flux.

En 2018, environ un milliard de personnes vivaient sans électricité. Or l'extension des réseaux est confrontée à de nombreux défis qui compromettent la soutenabilité de l'électrification traditionnelle. Les Projets d'Electrification Décentralisée (PED) offrent désormais des solutions réalistes pour un accès à l'électricité hors réseau dans les pays en développement. Cette thèse explore le rôle de la demande de fiabilité du service d’électricité comme déterminant d’une extension durable du réseau, et l'efficacité de l'offre d’électricité décentralisée pour l’atteinte des objectifs du développement durable. Avec des données sur les coupures observées par les ménages au Kenya, le premier chapitre établit la préférence des ménages pour la fiabilité du service d'électricité, laquelle pourrait constituer le levier majeur d’une extension efficace du réseau. Dans le deuxième chapitre, une méta-analyse consolidant 112 évaluations de projets décentralisés montre que la technologie, la capacité et la gouvernance supportent les choix de conception les plus déterminants pour atteindre les objectifs du développement durable. Le troisième chapitre explore la gamme d'objectifs atteints par les pratiques de l’électrification décentralisée. Les plus efficaces sont celles qui adressent les utilisations productives et les services publics, ainsi que les micro-réseaux dans les zones éloignées, qui ont des impacts positifs sur l’information et la communication. La probabilité d'impacts positifs augmente avec la capacité des systèmes solaires individuels, qui favorisent la santé et l’éducation. / By 2018, about one billion people were living without electricity. The extension of electrical grids is facing many challenges that jeopardize the sustainability of traditional electrification. Decentralized Electrification Projects (DEP) now offer feasible solutions for offgrid access to electricity in developing countries. This thesis explores the role of the demand for reliability of the electricity service as a determinant of sustainable extension of the electrical grid, and the efficiency of electricity supply by DEP to achieve the sustainable development goals. With data on outages observed by households in Kenya, the first chapter establishes the households' preference for the reliability of electricity service, which could be the major lever for effective network expansion. In the second chapter, a meta-analysis consolidating 112 decentralized project evaluations shows that technology, capacity and governance support the design choices that are most critical to achieving the sustainable development goals. The third chapter explores the range of objectives achieved by decentralized electrification practices. The most effective are those that address productive uses and public services, as well as micro-networks in remote areas, which have positive impacts on information and communication. The likelihood of positive impacts increases with the capacity of solar home systems, which favor health and education.

This thesis analyses impact of exchange rate exposure in Czech Republic on sample of ten Czech companies. Empirical part of thesis builds on Nazl, Kar, Akel (2014) and through market-based approach states significant impact of exchange rate exposure for 40 % of companies. Higher robustness of results was achieved through improvements in the methodology which, contrary to related literature, eliminates endogeneity of market index through instrumental variable. Surprisingly, the correlations between exchange rates and stocks of Czech companies are positive. An alternative model considering ROA of individual companies as dependent variable was used to confirm these results. The resulting impact of exchange rate exposure of alternative model is opposite. This inconsistency of the results of both models is confusing. The sudden change in exchange rate policy of the Czech National Bank in November 2013 did not affect the sensitivity of the relationship between exchange rates and stocks. The reaction of stock market in November 2013 indicates that policy change made by CNB was not entirely expected. Contrary to the related literature, higher data aggregation decreases the significance of the exchange rate exposure, signifying higher ability of Czech companies to reduce exchange rate risk in longer...

Cette thèse traite de l’identification de systèmes dynamiques à partir de données échantillonnées à pas variable. Ce type de données est souvent rencontré dans les domaines biomédical, environnemental, dans le cas des systèmes mécaniques où un échantillonnage angulaire est réalisé ou lorsque les données transitent sur un réseau. L’identification directe de modèles à temps continu est l’approche à privilégier lorsque les données disponibles sont échantillonnées à pas variable ; les paramètres des modèles à temps discret étant dépendants de la période d’échantillonnage. Dans une première partie, un estimateur optimal de type variable instrumentale est développé pour estimer les paramètres d’un modèle Box-Jenkins à temps continu. Ce dernier est itératif et présente l’avantage de fournir des estimées non biaisées lorsque le bruit de mesure est coloré et sa convergence est peu sensible au choix du vecteur de paramètres initial. Une difficulté majeure dans le cas où les données sont échantillonnées à pas variable concerne l’estimation de modèles de bruit de type AR et ARMA à temps continu (CAR et CARMA). Plusieurs estimateurs pour les modèles CAR et CARMA s’appuyant sur l’algorithme Espérance-Maximisation (EM) sont développés puis inclus dans l’estimateur complet de variable instrumentale optimale. Une version étendue au cas de l’identification en boucle fermée est également développée. Dans la deuxième partie de la thèse, un estimateur robuste pour l'identification de systèmes à retard est proposé. Cette classe de systèmes est très largement rencontrée en pratique et les méthodes disponibles ne peuvent pas traiter le cas de données échantillonnées à pas variable. Le retard n’est pas contraint à être un multiple de la période d’échantillonnage, contrairement à l’hypothèse traditionnelle dans le cas de modèles à temps discret. L’estimateur développé est de type bootstrap et combine la méthode de variable instrumentale itérative pour les paramètres de la fonction de transfert avec un algorithme numérique de type gradient pour estimer le retard. Un filtrage de type passe-bas est introduit pour élargir la région de convergence pour l’estimation du retard. Tous les estimateurs proposés sont inclus dans la boîte à outils logicielle CONTSID pour Matlab et sont évalués à l’aide de simulation de Monte-Carlo / The output of a system is always corrupted by additive noise, therefore it is more practical to develop estimation algorithms that are capable of handling noisy data. The effect of white additive noise has been widely studied, while a colored additive noise attracts less attention, especially for a continuous-time (CT) noise. Sampling issues of CT stochastic processes are reviewed in this thesis, several sampling schemes are presented. Estimation of a CT stochastic process is studied. An expectation-maximization-based (EM) method to CT autoregressive/autoregressive moving average model is developed, which gives accurate estimation over a large range of sampling interval. Estimation of CT Box-Jenkins models is also considered in this thesis, in which the noise part is modeled to improve the performance of plant model estimation. The proposed method for CT Box-Jenkins model identification is in a two-step and iterative framework. Two-step means the plant and noise models are estimated in a separate and alternate way, where in estimating each of them, the other is assumed to be fixed. More specifically, the plant is estimated by refined instrumental variable (RIV) method while the noise is estimated by EM algorithm. Iterative means that the proposed method repeats the estimation procedure several times until a optimal estimate is found. Many practical systems have inherent time-delay. The problem of identifying delayed systems are of great importance for analysis, prediction or control design. The presence of a unknown time-delay greatly complicates the parameter estimation problem, essentially because the model are not linear with respect to the time-delay. An approach to continuous-time model identification of time-delay systems, combining a numerical search algorithm for the delay with the RIV method for the dynamic has been developed in this thesis. In the proposed algorithm, the system parameters and time-delay are estimated reciprocally in a bootstrap manner. The time-delay is estimated by an adaptive gradient-based method, whereas the system parameters are estimated by the RIV method. Since numerical method is used in this algorithm, the bootstrap method is likely to converge to local optima, therefore a low-pass filter has been used to enlarge the convergence region for the time-delay. The performance of the proposed algorithms are evaluated by numerical examples

Submitted by Gustavo Rabello de Castro (grdcastro@outlook.com) on 2016-01-17T15:36:58Z No. of bitstreams: 1 Dissertacao Final.pdf: 1716177 bytes, checksum: 6516904780e3dae7837ee9b481d63ba7 (MD5) / Approved for entry into archive by BRUNA BARROS (bruna.barros@fgv.br) on 2016-01-21T17:18:28Z (GMT) No. of bitstreams: 1 Dissertacao Final.pdf: 1716177 bytes, checksum: 6516904780e3dae7837ee9b481d63ba7 (MD5) / Approved for entry into archive by Maria Almeida (maria.socorro@fgv.br) on 2016-02-11T17:59:08Z (GMT) No. of bitstreams: 1 Dissertacao Final.pdf: 1716177 bytes, checksum: 6516904780e3dae7837ee9b481d63ba7 (MD5) / Made available in DSpace on 2016-02-11T17:59:18Z (GMT). No. of bitstreams: 1 Dissertacao Final.pdf: 1716177 bytes, checksum: 6516904780e3dae7837ee9b481d63ba7 (MD5) Previous issue date: 2015-04-28 / In this work we focus on tests for the parameter of an endogenous variable in a weakly identi ed instrumental variable regressionmodel. We propose a new unbiasedness restriction for weighted average power (WAP) tests introduced by Moreira and Moreira (2013). This new boundary condition is motivated by the score e ciency under strong identi cation. It allows reducing computational costs of WAP tests by replacing the strongly unbiased condition. This latter restriction imposes, under the null hypothesis, the test to be uncorrelated to a given statistic with dimension given by the number of instruments. The new proposed boundary condition only imposes the test to be uncorrelated to a linear combination of the statistic. WAP tests under both restrictions to perform similarly numerically. We apply the di erent tests discussed to an empirical example. Using data from Yogo (2004), we assess the e ect of weak instruments on the estimation of the elasticity of inter-temporal substitution of a CCAPM model. / Este trabalho trata de testes para o parâmetro de uma variável endógena em modelos de regressão com variáveis instrumentais fracas. Propomos uma nova restrição para o viés dos testes weighted average power (WAP), desenvolvidos em Moreira e Moreira (16, 2013). A motivação para essa nova restrição se baseia na eficiência do teste score sob a hipótese de identificação forte. Essa hipótese permite reduzir o custo computacional dos testes WAP, substituindo a restrição de strongly unbiased. Esta ultima demanda que, sob a hipótese nula, o teste seja ortogonal a uma dada estatística com sua dimensão dada pelo número de instrumentos. A restrição aqui proposta exige somente que o teste seja não correlacionado com uma combinação linear dessa estatística. Nas simulações, ambos os testes apresentam um desempenho numericamente similar. Aplicamos ainda os testes discutidos neste trabalho na estimação da elasticidade de substituição intertemporal de um modelo CCAPM.