Dissertations / Theses on the topic 'Dynamic panel GMM method'

The rapid growth of financial markets and the increasing diffusion of corporate ownership have placed tremendous emphasis on the effectiveness of corporate governance in resolving agency conflicts within the firm. This study investigates the corporate governance and firm performance/failure relation by implementing various econometric modelling methods to disaggregate causal relations and spurious correlations. Using a panel dataset of Australian firms, a comprehensive suite of corporate governance mechanisms are considered; including the ownership, remuneration, and board structures of the firm. Initial ordinary least squares (OLS) and fixed-effects panel specifications report significant causal relations between various corporate governance measures and firm outcomes. However, the dynamic generalised method of moments (GMM) results indicate that no causal relations exist when taking into account the effects of simultaneity, dynamic endogeneity, and unobservable heterogeneity. Moreover, these results remain robust when accounting for the firm??s propensity for fraud. The findings support the equilibrium theory of corporate governance and the firm, suggesting that a firm??s corporate governance structure is an endogenous characteristic determined by other firm factors; and that any observed relations between governance and firm outcomes are spurious in nature. Chapter 2 examines the corporate governance and firm performance relation. Using a comprehensive suite of corporate governance measures, this chapter finds no evidence of a causal relation between corporate governance and firm performance when accounting for the biases introduced by simultaneity, dynamic endogeneity, and unobservable heterogeneity. This result is consistent across all firm performance measures. Chapter 3 explores the corporate governance and likelihood of firm failure relation by implementing the Merton (1974) model of firm-valuation. Similarly, no significant causal relations between a firm??s corporate governance structure and its likelihood of failure are detected when accounting for the influence of endogeneity on the parameter estimates. Chapter 4 re-examines the corporate governance and firm performance/failure relation within the context of corporate fraud. Using KPMG and ASIC fraud databases, the corporate governance and firm outcome relations are estimated whilst accounting for the firms?? vulnerability to corporate fraud. This chapter finds no evidence of a causal relation between corporate governance and firm outcomes when conditioning on a firm??s propensity for fraud.

Un financement par Equity lines permet à une entreprise de mobiliser des fonds supplémentaires à tout moment durant une période convenue afin de renforcer ses capitaux propres. Peu de recherches se concentrent sur ce mécanisme de financement par Equity lines et aucune sur les déterminants de la structure du capital, des mécanismes internes liés à la gouvernance et du contenu informationnel des marchés boursiers. Cette thèse s'articule autour de trois segments de recherche inter-reliés. Elle explore l'utilisation des mécanismes d’Equity lines, afin de mieux appréhender les critères qui motivent le recours à ce type de financement, en examinant à la fois les facteurs spécifiques aux entreprises et ceux relevant de leur environnement général. Notre recherche montre que les opportunités de croissance, la liquidité et le degré de développement du marché boursier (maturité, expérience des intermédiaires financiers, nombre de transactions, etc.) constituent les facteurs déterminant dans le choix d’un financement par Equity lines. Cette thèse prouve également que ces financements se retrouvent dans des entreprises à actionnariat managérial, dirigées par des hommes non enracinés, relativement âgés et moins diplômés, qui assurent la fonction de président du conseil d'administration. Nos travaux examinent enfin le contenu informationnel lors de l'annonce de l'émission d'Equity lines. Ils montrent que la réaction négative du marché autour de la date d'annonce, et la persistance de cet effet après la date d’annonce, soutient l’hypothèse de la signalisation d'informations privilégiées. Les différentes conclusions de cette thèse enrichissent le corpus de connaissances sur la structure du capital, la gouvernance d'entreprise et les marchés financiers. Mais les conséquences en termes de risques inhérents aux investissements utilisant cet instrument financier suscitent des interrogations à ce jour. Il s’agit notamment du risque de perte du capital investi, associé à une forte pression à la baisse sur le cours de l'action
Equity lines financing allows a manager to raise additional funds at any time during an agreed period to strengthen his or her equity. Little recent research has focused on this Equity lines financing mechanism and none on the determinants of capital structure, internal governance mechanisms, and the information content of equity markets. This thesis is structured around a set of interrelated research segments. It explores the use of Equity lines mechanisms to better understand the factors that motivate the use of this type of financing, by examining both the factors specific to companies and those related to their general environment. Our research shows that growth opportunities, liquidity, the degree of development of the stock market (maturity, experience of financial intermediaries, number of transactions, etc.) are the factors that determine the choice of Equity lines financing. This thesis also proves that male executives, who are not entrenched, relatively old and less educated, also serve as chairman of the board of companies with managerial shareholding. Our work evaluates the information content of the announcement of the Equity lines issue. We show that the negative market reaction around the announcement date, and the persistence of this effect after the announcement date, support the hypothesis of inside information reporting. The various findings of this thesis add to the body of knowledge on capital structure, corporate governance and financial markets. The consequences on the risks inherent in investments using this financial instrument are questionable. These include the risk of losing the capital invested, which is associated with strong downward pressure on the share price

The aim of the work is twofold. First, we investigate the properties of the dynamic panel data (DPD) GMM estimator when the instrument count is high. We introduce the extraction of principal components fromthe instrument matrix as an effective strategy to reduce the number of instruments. Through Monte Carlo experiments, we want to compare the performances of the GMM estimators when the instrument set is factorized, collapsed or limited. Second, we estimate fiscal response functions on simulated panels and on real data to identify the best-performing estimator in this context, where endogeneity and instrument proliferation issues are unavoidable. The dissertation consists of three chapters. The first reviews the literature of DPD estimation and presents the issue of instrument proliferation in DPD GMM estimation. The second introduces the principal component analysis (PCA) to reduce the dimension of the instrument matrix and compares the performances of the factorized, limited and collapsed GMM estimators, finding them similar. Though the simulated models are extremely simplified, the PCA seems to be promising. The third chapter simulates fiscal response functions and investigates the properties of DPD estimators in fiscal rules estimation; the fiscal rules are then estimated on real data for EMU Countries. The system GMM estimator is the best-performing here. Instrument proliferation does not bias the estimates; collapsing and lag truncation of the instrument matrix can lead to misleading results, while the factorized estimator performs well. Discretionary policies within the EMU are systematically found a-cyclical.

We estimate the speed of income convergence for a sample of 196 European NUTS 2 regions over the period 1985-1999. So far there is no direct estimator available for dynamic panels with strong spatial dependencies. We propose a two-step procedure, which involves first spatial filtering of the variables to remove the spatial correlation, and application of standard GMM estimators for dynamic panels in a second step. Our results show that ignorance of the spatial correlation leads to potentially misleading results. Applying a system GMM estimator on the filtered variables, we obtain a speed of convergence of 6.9 per cent and a capital elasticity of 0.43.
Series: EI Working Papers / Europainstitut

Europe is in the midst of its deepest crisis since the 1930s where unsustainable debt-to-GDP levels are among the most alarming issues. It is so critical that it is unsure if the Euro can be saved. The risk of moral hazard increases within EMU when governments are taking too much risk in their public debt policies due to the anticipation that ECB or other Member States would eventually bail them out. Moreover, the SGP imposes restrictions on government deficits and debts but have previously failed to enforce them. The weakness seen in the past is that no sanctions have been put in place once the limits have been breached and the SGP is therefore incredible. Previous research on common pool and debt spillovers in a monetary union point to an upward drift of public debt as countries join the EMU. Does this argument hold true? In order to find out, 25 OECD countries between the years of 1995 and 2010 are analyzed using System GMM Arellano-Bover/Blundell-Bond one-step estimator. The primary balance, the interest payments, and GDP growth are regressed respectively in order to see through what channel EMU displays its effect. One regression will cover the entire time period and another will only cover the years from 1995 to 2007 in order to isolate the effects of the current crisis. The results, based on the years over the entire time period (including the crisis) suggest that the effect of an EMU Membership goes via the Interest payments which it is connected to positively. By using the equation of debt dynamics, the fact that net debt interest payments are higher for a country within EMU indicates, all else equal, that they have on average higher levels of debt. Nevertheless, this realization might be a crisis phenomenon and the implication of this is not clear. However more importantly, the regressions based on the years of 1995 and 2007 (prior to the crisis) did not display any significant results. These results indicate that there is no significant relationship between a country’s membership in EMU and its level of debt prior to the crisis.

This study examines the impact of fiscal deficits on economic growth in developing countries. Based on deduction from the relevant theoretical and empirical literature, the study tests the following hypotheses regarding the impact of fiscal deficits on economic growth. First, fiscal deficits have significant positive or negative impact on economic growth in developing countries. Second, the impact of fiscal deficits on economic growth depends on the size of deficits as a percentage of GDP – that is, there is a non-linear relationship between fiscal deficits and economic growth. Third, the impact of fiscal deficits on economic growth depends on the ways in which deficits are financed. Fourth, the impact of fiscal deficits on economic growth depends on what deficit financing is used for. The study also examines whether there are any significant regional differences in terms of the relationship between fiscal deficits and economic growth in developing countries. The study uses panel data for thirty-one developing countries covering the period 1972- 2001, which is analysed based on the econometric estimation of a dynamic growth model using the Arellano and Bond (1991) generalised method of moments (GMM) technique. Overall, the results suggest the following. First, fiscal deficits per se have no any significant positive or negative impact on economic growth. Second, by contrast, when the deficit is substituted by domestic and foreign financing, we find that both domestic and foreign financing of fiscal deficits exerts a negative and statistically significant impact on economic growth with a lag. Third, we find that both categories of economic classification of government expenditure, namely, capital and current expenditure, have no significant impact on economic growth. When government expenditure is disaggregated on the basis of a functional classification, the results suggest that spending on education, defence and economic services have positive but insignificant impact on growth, while spending on health and general public services have positive and significant impact. Fourth, in terms of regional differences with regard to the estimated relationships, the study finds that, while there are some regional differences between the four different regions represented in our sample of thirty-one developing countries - namely, Asia and the Pacific, Latin America and the Caribbean, Middle East and North Africa, and Sub-Saharan Africa – these differences are not statistically significant. On the basis of these findings, the study concludes that fiscal deficits per se are not necessarily good or bad for economic growth in developing countries; how the deficits are financed and what they are used for matters. In addition, the study concludes that there are no statistically significant regional differences in terms of the relationship between fiscal deficits and economic growth in developing countries.

This dissertation evaluates the empirical relation between the value-added tax (VAT) and the level of aggregate consumption. Furthermore, it develops a theoretical framework and an empirical analysis to study the impact of the VAT, as a form of taxing consumption, on capital accumulation, productivity growth, and overall economic growth. While recent theoretical work shows that the VAT may boost capital accumulation and growth by encouraging more savings, we find that the net impact of consumption taxes on growth and its sources is theoretically ambiguous, and depends on the interaction between utility parameters, the interest rate, and the tax structure. Moreover, we develop a theoretical model to study the tax design problem in order to rationalize the observed variation in effective VAT rates over time in our sample. This framework considers both equity and efficiency as important factors determining optimal tax structure, and we identify conditions under which taxes could be evolving or constant over time. Empirically, we use a panel of 15 European Union countries and employ the recently developed GMM dynamic panel techniques. After controlling for the potential biases associated with persistence, endogeneity, simultaneity, measurement error, omitted variables, and unobserved country-specific effects, we find that (i) the VAT exerts a negative impact on the level of aggregate consumption, (ii) the VAT affects physical capital accumulation positively, which feeds through to overall GDP growth, and (iii) productivity growth seems to be a less relevant channel for the VAT to influence economic growth.

Migration is a multidimensional phenomenon requiring an interdisciplinary approach. This thesis studies some economic aspects of the internal migration of labour. A model of migration as investment in human capital is applied throughout the thesis to study economic causes and consequences of internal migration on a micro level. Various predictions from the theory are verified on longitudinal micro data from the Household Income and Labour Dynamics in Australia (HILDA) survey. The thesis is composed of three essays: (1) Causes of migration, the individual level push and pull factors facilitating or hampering mobility and representing both costs and benefits to migration, are studied in Chapter 2. A binary dependent variable model for the likelihood of an individual migration decision is estimated on panel data from the HILDA survey by means of the probit model with individual random effects. The main results are that those not in the labour force, similarly to the unemployed, are more mobile than the employed; and that higher individual wages and greater remoteness from larger urban centres also increase the likelihood of migration. (2) Chapter 3 studies wage returns to internal migration. Evidence is sought for the theoretical predictions of the traditional human capital model of investment in migration about a positive wage premium: positive returns to migration distance and human capital. Using individual-level data from the HILDA Survey and applying a system GMM to a dynamic panel earnings model, it is found that in the short-run there are returns to distance which increase with the level of education and decline with the level of pre-migration wage. The conclusion is that internal migration in Australia is a good strategy only for better educated and lower income individuals. (3) Several theoretical models of migration destination search are presented in Chapter 4. It discusses two models of migration as an outcome of the fixed-sample-size search and the sequential search. A model with endogenous investment in search activity demonstrates that lower initial utility increases chances to participate in search and that the likelihood of migration depends on budget constraints: those of the poor who can afford to buy relatively more information are expected to gain more than others.

This study examines the impact of fiscal deficits on economic growth in developing countries. Based on deduction from the relevant theoretical and empirical literature, the study tests the following hypotheses regarding the impact of fiscal deficits on economic growth. First, fiscal deficits have significant positive or negative impact on economic growth in developing countries. Second, the impact of fiscal deficits on economic growth depends on the size of deficits as a percentage of GDP - that is, there is a non-linear relationship between fiscal deficits and economic growth. Third, the impact of fiscal deficits on economic growth depends on the ways in which deficits are financed. Fourth, the impact of fiscal deficits on economic growth depends on what deficit financing is used for. The study also examines whether there are any significant regional differences in terms of the relationship between fiscal deficits and economic growth in developing countries. The study uses panel data for thirty-one developing countries covering the period 1972- 2001, which is analysed based on the econometric estimation of a dynamic growth model using the Arellano and Bond (1991) generalised method of moments (GMM) technique. Overall, the results suggest the following. First, fiscal deficits per se have no any significant positive or negative impact on economic growth. Second, by contrast, when the deficit is substituted by domestic and foreign financing, we find that both domestic and foreign financing of fiscal deficits exerts a negative and statistically significant impact on economic growth with a lag. Third, we find that both categories of economic classification of government expenditure, namely, capital and current expenditure, have no significant impact on economic growth. When government expenditure is disaggregated on the basis of a functional classification, the results suggest that spending on education, defence and economic services have positive but insignificant impact on growth, while spending on health and general public services have positive and significant impact. Fourth, in terms of regional differences with regard to the estimated relationships, the study finds that, while there are some regional differences between the four different regions represented in our sample of thirty-one developing countries - namely, Asia and the Pacific, Latin America and the Caribbean, Middle East and North Africa, and Sub-Saharan Africa - these differences are not statistically significant. On the basis of these findings, the study concludes that fiscal deficits per se are not necessarily good or bad for economic growth in developing countries; how the deficits are financed and what they are used for matters. In addition, the study concludes that there are no statistically significant regional differences in terms of the relationship between fiscal deficits and economic growth in developing countries.

La présente thèse tente de savoir s’il est opportun pour les pays en développement les moins avancés de s’engager davantage dans le processus de globalisation financière pour promouvoir leur croissance, et si ce processus influence les effets des instabilités, financière et monétaire, sur cette dernière. A cette fin, la thèse se déroule en trois parties. Avant d’examiner le cadre théorique de la globalisation financière, la première partie esquisse sa genèse avec en arrière-fond la recherche d’une réponse au problème de sa régulation. La deuxième partie s’intéresse à la littérature sur les effets de la globalisation financière sur la croissance, afin d’en tirer les enseignements pour une étude de 72 pays en développement à revenu bas de 1972 à 2011. La troisième partie se focalise sur les impacts de la globalisation financière et des deux instabilités considérées isolément, puis en interaction avec la globalisation sur la croissance à travers deux études empiriques basées sur le même cadre spatio-temporel que l’étude précédente. Ces dernières sont précédées par une revue des relations entre la globalisation financière, l’instabilité financière puis monétaire et la croissance, avec une analyse théorique de l’instabilité financière. Il en ressort que les instabilités, financière et monétaire, ont des effets négatifs sur la croissance, tandis que la globalisation financière, et en particulier la globalisation par l’investissement contrairement à celle par l’endettement, promeut les bienfaits des politiques économiques et du commerce extérieur, en plus de son effet positif direct sur la croissance même en présence des deux instabilités dont elle diminue les effets négatifs
This thesis examines whether or not it is beneficial for least developed countries to engage more in the process of financial globalization in pursuit of their economic growth, and if this process influences the effects of financial and monetary instability on the latter. This thesis is divided into three parts. Before examining the theoretical framework of financial globalization, the first part sketches its genesis on a background of the research for an answer to the problem of its regulation. The second part focuses on the literature on the impact of financial globalization on growth. This is done in order to draw lessons for the establishment of a study covering 72 low-income developing countries over the period 1972-2011. The third part centers on the impact on economic growth of financial globalization and the two aforementioned types of instability, discussed both separately and in conjunction. Evidence is provided by two empirical studies based on the same spatio-temporal framework as the previous one. These studies are preceded by a review of the literature on the relationship between financial globalization, financial and then monetary instability and growth, in addition to a theoretical analysis of financial instability. This illustrates that financial and monetary instability have negative effects on growth, while financial globalization and in particular investment-globalization, unlike indebtedness-globalization, promotes the benefits of macroeconomic policies and international trade. This can be find in addition to its direct positive effect on growth, even in the presence of the two instabilities of which it reduces the negative effects

Esta dissertação tem por objeto de estudo métodos de estimação para modelos dinâmicos com dados de painel. Estes modelos são usualmente estimados pelo método dos momentos generalizados (GMM), sendo o principal objetivo desta dissertação a análise do desempenho de algumas variantes desse método em pequenas amostras, de modo a verificar se as suas propriedades assimptóticas conhecidas são de alguma forma indicadoras das suas propriedades em amostras finitas. Assim, através dum estudo de simulação de Monte Carlo, examinou-se o comportamento desses estimadores em amostras finitas em vários cenários alternativos, que passam: por considerar o caso homoscedástico e heteroscedástico para a componente do termo do erro variante no tempo; por gerar esta componente do erro de acordo com as distribuições Normal, t-Student e Qui-Quadrado; por considerar diferentes valores para a dimensão da amostra tanto em termos seccionais como temporais; por considerar diferentes pesos de cada componente do erro na variância da variável dependente; e por considerar diferentes valores para o parâmetro auto-regressivo. De entre os estimadores GMM, os estimadores SYS revelam um comportamento muito melhor, mostrando-se claramente preferíveis aos DIF para valores de δ` Próximos de um, e evidenciando uma certa robustez face aos vários cenários analisados. Em particular, a Versão proposta por Windmeijer (2000) parece ser a mais indicada para trabalho empírico. /ABSTRACT - In this dissertation we studied estimation methods for dynamic models for panel data. These models are usually estimated by the generalized method of moments (GMM), being the main goal of this dissertation the analysis of the small sample properties of the main variants of that method. Thus, through a Monte Carlo simulation study, the behaviour of those estimators was examined in finite samples in several alternative sceneries, including: homoscedastic and heteroscedastic time-variant error terms; error terms generated according to the Normal, t-Student and chi-square distributions; different cross-sectional and time-series sample sizes; different weights of each error component in the variance of the dependent variable; different values for the autoregressive parameter. The best behaviour was displayed by the variant SYS, which is clearly preferable to the variant DIF for values of the auto-regressive parameter close to the unity and seems to be robust to the several sceneries analyzed. Among the alternative SYS estimators, the version proposed by Windmeijer (2000) appears to be the most suitable for empiric Work.

La présente thèse contribue à la littérature sur trois principaux axes de recherche relatifs à la structure du capital: les déterminants de la structure du capital, la profitabilité et la demande de travail. (i) Le fondement théorique des déterminants de la structure du capital montre qu'il existe trois modèles qui peuvent expliquer la structure du capital: la théorie de ratio optimal d'endettement, la théorie hiérarchique de financement et récemment la théorie de market timing. De plus, l'évaluation empirique montre un effet positif des coûts d'ajustement et de la garantie. Par contre, l'opportunité de croissance, l'impôt non lié à la dette et la rentabilité sont corrélés de façon négative avec l'endettement. (ii) L'impact de la structure du capital sur la profitabilité peut être expliqué par trois théories essentielles: la théorie du signal, l'influence de la fiscalité et la théorie de l'agence. L'analyse empirique a permis de distinguer trois groupes différents de secteurs: pour le premier groupe, la structure du capital n'a aucune incidence sur la profitabilité. Le deuxième, c'est le groupe où l'endettement affecte négativement la profitabilité de manière linéaire. Le dernier groupe se caractérise par la présence d'un effet négatif de façon linéaire et non linéaire (iii) Théoriquement, un impact négatif de la structure du capital sur la demande de travail est prévu. L'application empirique montre une hétérogénéité des comportements entre les secteurs en ce qui concerne l'effet de l'endettement sur la demande de travail, donc, il existe aussi trois groupes différents de secteurs (pas d'effet, effet négatif linéaire et effet négatif linéaire et non linéaire). De plus, la magnitude de l'effet de l'endettement sur la demande de travail et sur la profitabilité dépend, non seulement du secteur, mais aussi de la taille d'entreprise.

La présente thèse contribue à la littérature sur trois principaux axes de recherche relatifs à la structure du capital: les déterminants de la structure du capital, la profitabilité et la demande de travail. (i) Le fondement théorique des déterminants de la structure du capital montre qu’il existe trois modèles qui peuvent expliquer la structure du capital: la théorie de ratio optimal d’endettement, la théorie hiérarchique de financement et récemment la théorie de market timing. De plus, l’évaluation empirique montre un effet positif des coûts d’ajustement et de la garantie. Par contre, l’opportunité de croissance, l’impôt non lié à la dette et la rentabilité sont corrélés de façon négative avec l’endettement. (ii) L’impact de la structure du capital sur la profitabilité peut être expliqué par trois théories essentielles: la théorie du signal, l’influence de la fiscalité et la théorie de l’agence. L’analyse empirique a permis de distinguer trois groupes différents de secteurs: pour le premier groupe, la structure du capital n’a aucune incidence sur la profitabilité. Le deuxième, c’est le groupe où l’endettement affecte négativement la profitabilité de manière linéaire. Le dernier groupe se caractérise par la présence d’un effet négatif de façon linéaire et non linéaire (iii) Théoriquement, un impact négatif de la structure du capital sur la demande de travail est prévu. L’application empirique montre une hétérogénéité des comportements entre les secteurs en ce qui concerne l’effet de l’endettement sur la demande de travail, donc, il existe aussi trois groupes différents de secteurs (pas d’effet, effet négatif linéaire et effet négatif linéaire et non linéaire). De plus, la magnitude de l’effet de l’endettement sur la demande de travail et sur la profitabilité dépend, non seulement du secteur, mais aussi de la taille d’entreprise
This thesis contributes to the literature in three main areas of research about capital structure: the determinants of capital structure, the profitability and the labour demand. (i) The theoretical basis of the determinants of capital structure shows that there are three models that explains the capital structure: Trade-Off theory, Pecking Order theory and Market Timing theory. Further, the empirical evaluation shows a positive effect of the adjustment costs and the tangibility. On the other hand, growth opportunity, non-debt tax shield and profitability are negatively correlated with debt. (ii) The impact of capital structure on profitability can be explained by three essential theories: signal theory, tax theory and the agency costs theory. The empirical analysis allowed to distinguish three different groups of sectors: for the first group, the capital structure has no impact on profitability. The second, it is the group where the debt affects negatively the profitability in a linear way. The last group is characterized by the presence of a negative effect in a linear and nonlinear way. (iii) Theoretically, a negative impact of the capital structure on labour demand is expected. The empirical application shows heterogeneity of behavior between sectors regarding the impact of debt on the demand for labor; therefore, there are three different groups of sectors (i.e. no effect, negative linear effect, and linear and non linear negative effect). Furthermore, the magnitude of the effect of debt on the labour demand and on the profitability depends not only of the sector, but also of the size of company

The aim of this work is the development of a refined reduced order model suitable for numerical applications in solid and fluid mechanics with a remarkable reduction in computational cost. Nowadays, numerical reduced order models are widely exploited in many areas, such as aerospace, mechanical and biomechanical engineering for structural analysis, fluid dynamic analysis and coupled (aeroelastic) fluid-structure interaction analysis. One-dimensional (1D) structural models, commonly known as beams, are for instance used in many applications to analyze the structural behavior of slender bodies, such as columns, arches, blades, aircraft wings, bridges, skyscrapers, rotor and wind turbine blades. One-dimensional structural elements are simpler and computationally more efficient than 2D (plate/shell) and 3D (solid) elements. This feature makes beam theories still very attractive for the static, dynamic response, free vibration and aeroelastic analyses, despite the approximations which they introduce in the simulation. Recently, 1D models are intensively exploited for the simulation of the human cardiovascular system under either physiological or pathological conditions. As it is easily comprehensible, fluid flows in pipes, channel, capillaries or even arteries are particularly suitable for the application of one-dimensional models also to fluid dynamics. Typically, one-dimensional models for fluid dynamics and fluid-structure interaction (FSI) problems are again remarkably more efficient than three-dimensional methods in terms of computational cost. A key point for reduced order models is the capability in simulating in an accurate way the investigated physical problem. For instance, in last decades the growing use of advanced composite and sandwich materials in thin-walled beam-like structures has revealed that 1D theories have to be refined in order to predict the behavior of such complex structures with high fidelity. For this purpose, a higher-order one-dimensional method is introduced in this work and its capabilities are highlighted and discussed. The present work is subdivided into three fundamental parts corresponding to the physical fields the proposed refined model is applied to. Firstly, a structural part presents the formulation of a displacement-based higher-order one-dimensional model for the analysis of beam-like structures. Classical beam theories (Euler-Bernoulli and Timoshenko) have intrinsic limitations which preclude their applications for the analysis of a wide class of engineering problems. The Carrera Unified Formulation (CUF) is employed to introduce a hierarchical modeling with a variable order of expansion for the displacement unknowns over the beam cross-section. The finite element method (FEM) is used to handle arbitrary geometries and loading conditions. The influence of higher-order effects over the cross-section deformation, not detectable by classical and low-order beam theories, on the static, free vibration and time-dependent response of several structures with arbitrary cross-section geometries and made of arbitrary materials is remarked through the numerical results presented. Secondly, an aeroelastic part describes the extension of the refined structural model to the static aeroelastic analysis of lifting surfaces made of metallic and composite materials. A coupled aeroelastic computational model based on the Vortex Lattice aerodynamic Method and the finite element method (FEM) is formulated. A refined aeroelastic approach is also presented by replacing the Vortex Lattice aerodynamic Method with the more powerful 3D Panel Method. Comparison with results obtained by existing plate/shell aeroelastic models shows that the present 1D model could result less expensive from the computational point of view with respect to shell cases with same accuracy. The effect of the cross-section deformation on the aeroelastic static response and on the critical wing divergence velocity is evaluated for different wing configurations. The beneficial effects of aeroelastic tailoring in the case of wings made of composite anisotropic materials are also confirmed by using the present model. Finally, a third part concerning the use of the refined one-dimensional CUF model for fluid dynamic problems is presented. The basic partial differential equations (PDEs) of fluid mechanics (Navier-Stokes and Stokes equations) are faced and 1D refined models with variable velocity-pressure accuracy are presented on the basis of the one-dimensional Carrera Unified Formulation and the finite element method. The application of these higher-order models to describe the three-dimensional fluid flow evolution on a computational domain is formulated for the Stokes problem. The present approach reveals its capabilities in predicting accurately, with a reduced computational cost with respect to more consuming two-dimensional or three-dimensional methods, nonclassical and complex fluid flows. Moreover, the numerical results show the promising potentiality of such an approach to the future extension of fluid-structure CUF-CUF models, i.e. the coupling of CUF models used for both structural and fluid dynamic analyses.

La question du développement inclusif dans les pays en développement est au cœur de cette thèse. Cette dernière s'articule autour de quatre chapitres sur les questions de politique fiscale et les questions liées à la croissance inclusive. Le chapitre 1 explore comment la politique fiscale de l’Etat affecte l'inclusivité de la croissance dans les pays en développement. Nous observons que la politique fiscale affecte la croissance inclusive de manière significative si et seulement si les pays ont de fortes qualités institutionnelles. En outre, notre résultat montre qu'il existe un seuil optimal au-delà duquel toute augmentation du taux d'imposition négativement la croissance inclusive. Le chapitre 2 examine les effets des composantes des dépenses publiques sur l'équité et la croissance dans les pays d’Afrique subsaharienne, notamment s'il est possible de concevoir des dépenses publiques en vue de promouvoir une société plus équitable sans sacrifier la croissance économique. Notre étude a permis de montrer que l’investissement en infrastructure a contribué à une croissance plus inclusive en Afrique subsaharienne que d'autres dépenses publiques. Ces résultats suggèrent que des programmes temporaires et bien ciblés devraient être mis en place pour aider ceux qui sont laissés pour compte par le processus de croissance. Le chapitre 3 cherche à savoir si les problèmes d’inégalités de revenus se sont posés ou non dans les périodes d'ajustement budgétaire en Côte d'Ivoire au cours de la période 1980-2014. Nos résultats montrent une amélioration de la performance de croissance après les épisodes de consolidation budgétaire, mais aussi des diminutions de l'écart de revenu dans les périodes suivantes les années d’ajustements budgétaires. Enfin, le chapitre 4 évalue la crédibilité des prévisions budgétaires et leurs effets sur le bien-être social dans les pays de la CEMAC et de l'UEMOA. Nous sommes aboutis aux résultats que l'inefficacité des prévisions budgétaires se produit dans la plupart des cas parce que les erreurs de prévisions sont proportionnelles à la prévision elle-même, mais aussi parce que les erreurs passées sont répétées dans le temps. En outre, une partie des erreurs de prévision des recettes peut s'expliquer par des chocs aléatoires survenus dans l'économie. Par conséquent, ces erreurs dans les prévisions de revenus considérées comme des chocs de politique budgétaire ont un effet négatif sur la croissance inclusive
The issue of inclusive development in developing countries is at the heart of this thesis. The latter revolves around four chapters on fiscal policy issues and inclusive growth-related matters. Chapter 1 explores how government tax policy affects the inclusiveness of growth in developing countries. Evidence is shown that tax policy affects significantly inclusive growth if and only if the countries have a strong institution quality like low corruption and a good bureaucratic policy. In addition, our result shows that there is an optimal tax beyond which, any increase in the personal income tax rate should have negative impact on inclusive growth. The Chapter 2 examines the effects of government expenditure components on both equity and growth in sub-Saharan countries, especially whether it is possible to design public spending to promote a more equitable society without sacrificing economic growth. We find that investment in infrastructure contributed to more inclusive growth in Sub-sub Saharan African economies than others government spending. These results suggest that temporary and well-targeted programs should be implemented to help those being left out by the growth process. The Chapter 3 investigates whether income inequality matters in the periods of fiscal adjustments in Côte d’Ivoire over the period 1980-2014. The results show an improvement in growth performance after fiscal consolidations episodes, but also income gap decreases in the periods ahead fiscal adjustments. Lastly, Chapter 4 assesses the credibility of fiscal forecasts and their social effects in CEMAC and WAEMU countries. We obtain evidence that the inefficiency of fiscal forecast occurs in most time because the forecast deviation is proportional to the forecast itself, but also because the past errors are repeated in the present. Furthermore, a part of revenue forecast errors can be explained by random shocks to the economy. Therefore, these errors in revenue forecast considered as fiscal policy shocks has a detrimental effect on inclusive growth

Cette thèse de doctorat porte sur la dynamique de l’emploi dans les entreprises et sur la relation entre la dynamique de l’emploi et l’innovation, avec une attention particulière portée sur les entreprises nouvellement créées. Cette thèse conceptualise théoriquement et analyse empiriquement les différents aspects de l’interaction complexe entre le changement technologique et la dynamique de l’emploi, en se concentrant sur les effets hétérogènes des différents types d’innovation sur la croissance de l’emploi. Compte tenu le rôle primordial joué par les nouvelles et jeunes entreprises dans le processus de destruction créatrice et leur apport à la création globale de l’emploi, cette thèse fournit une caractérisation de la contribution nette d’emplois des nouvelles entreprises dans un nombre important de pays, en utilisant des données micro-agrégées issues d’une nouvelle base de données. En outre, elle analyse comment un certain nombre de caractéristiques institutionnelles affectent la création nette d’emplois dans les start-ups, en se concentrant sur les effets hétérogènes des politiques sur les nouvelles entreprises et les entreprises déjà existantes. Cette thèse étudie enfin une caractéristique particulière des lois de distribution des taux de croissance de l’emploi, c’est-à-dire la volatilité de la croissance de l’emploi, que non seulement se révèle être une médiation cruciale des effets des politiques sur la création nette d’emplois, mais a aussi d’importantes implications à la fois micro- et macroéconomiques
This doctoral thesis focuses on employment dynamics in firms, and on the relationship between employment dynamics and innovation, with a particular focus on the entry process. It conceptualizes theoretically and analyses empirically different aspects of the complex interaction between technical change and employment dynamics, focusing on the heterogeneous effects of different types of innovation on employment growth. In the light of the prominent role of newly-born firms in shaping the creative destruction process and contributing to overall job creation, this thesis provides a characterization of the net job contribution by surviving entrants across a significant number of countries. Using newly collected representative micro-aggregated data, it further analyses whether and how a number of institutional characteristics affect start-ups’ net job creation, focusing on the heterogeneous effects of policies on entrants and incumbents. This thesis finally characterizes a particular feature of the employment growth distributions – employment growth volatility – that not only proves to be crucially mediating the effects of policies on entrants’ net job creation, but also has important micro and macroeconomic implications

This thesis investigates the determinants of the use of debt and leasing in the UK using a comprehensive measure of debt and leases, in recognition of the link between lease and debt-type financing decisions, based on financial contracting theory and the tax advantage hypothesis. The design of the study takes account three lacunae in our current understanding of this topic. Firstly, despite the fact that the capital structure literature is voluminous, it is perhaps surprising that relatively little research has been carried out on lease finance, given its significant role as a major source of finance for many firms. Secondly, the role of tax in the capital structure decision is unclear. Empirically testing for tax effects is challenging because spurious relationships may exist between the financing decision and many commonly used tax proxies. More importantly, our understanding of the impact of taxes on UK financing decisions is far from complete, especially since several major corporate tax reforms have taken place in the last decade. Thirdly, empirical evidence on capital structure determinants is also voluminous but far from conclusive. Notably, contradictory signs and significance levels are commonly observed. Using the standard regression approach invariably involves identification of the average behaviour of firms, and therefore does not measure diversity across firms. In response to these three major issues, this study employs empirical research methods, namely cross-sectional pooled regression, static and dynamic panel data regression, and quantile regression to analyse a large sample of 361 non-financial firms, drawn from the FTSE 350 and FTSE All-Small indices over the tax years 1995 through 2003. The operating lease data are estimated using the constructive capitalisation method while the simulated before-financing marginal tax rate is used to proxy for the firms’ tax status. The endogeneity of corporate tax status is evident since the use of simple tax proxy, the effective tax rate, leads to a spurious negative relation between debt usage and tax rates. The problem was avoided with a better measure of tax variable that is the simulated before-financing marginal tax rate where it is found that the empirical relationships between the tax factor and debt and leasing are consistent with those theoretical predictions. Furthermore, there is a clear distinction between the effect of taxes on debt and leasing where the firm’s marginal tax status is only relevant when managers make decisions on debt financing. The use of quantile regression method in the present study represents a novel approach in investigating the determinants of the use of debt and leasing. The results reveal that the determinants of debt and leasing are heterogeneous across the whole distribution of firms, consistent with the notion of heterogeneity as promoted by Beattie et al. (2006), but contradicting their claim that the large-scale regression approach cannot measure firms’ diversity. This finding implies that average model results (e.g., from OLS or panel data models) may not apply to the tails of debt and leasing levels, and hence assuming that the determinants of debt and leasing decisions are the same for all firms in the economy is clearly unrealistic. Using the dynamic panel data model, this thesis confirms that debt and leasing are substitutes rather than complements, and that the degree of substitutability is more pronounced among smaller firms, where the degree of information asymmetry is greater. More importantly, the use of a joint specification for debt and leasing improves our understanding of the determinants of the two fixed-claim financing instruments. There is also significant evidence to support the view that firm characteristics affect contracting costs which in turn impact on the choice between alternative forms of finance, namely equity, debt and leasing.

Mestrado em Econometria Aplicada e Previsão
Neste trabalho é apresentado inicialmente um levantamento da literatura referente a modelos dinâmicos, modelos de regressão não lineares, com variável dependente binária com dados de painel. Estes modelos podem incluir efeitos de várias fontes, tais como, variáveis específicas de interesse, heterogeneidade não observada dos indivíduos e valores desfasados da variável dependente. Neste trabalho iremos analisar aspetos relacionados com a especificação, estimação e inferência do modelo proposto por Wooldridge (2005). O modelo probit é um dos métodos de estimação viáveis de modelos de resposta binária. Este modelo irá ser usado para explicar o uso de internet no telemóvel no período que decorre entre Fevereiro de 2011 e Junho de 2001. Utilizou-se com este fim o software STATA.
This paper presents an initial survey of the literature on dynamic models, nonlinear regression models with binary dependent variable for panel data. These models may include effects of various sources, such as specific variables of interest, unobserved individual heterogeneity and lagged values of the dependent variable. In this paper we analyze aspects related to the specification, estimation and inference of the model proposed by Wooldridge (2005). The probit model is a viable estimation method for binary response models of the type described above. This model will be used to explain the use of mobile internet with dates between February 2011 and June 2011. The software STATA was used for this purpose.

The constant increase in public sector spending in the advanced economies, increases pressure on the revenue side of public budgets. The primary sources of public budgets are taxes. This raises a question of what type of tax instrument to choose in respect to meet the high efficiency in sourcing public budgets restriction and at the same time, to minimize the negative impact on the private sector and households. As generally effective tax is considered a consumption tax. But what is the real effect of this tax in the short run and long run? The aim of this thesis is to analyze the influence of value -- added tax (VAT) on household expendictures in the short and long run. At first I provide empirical test of the short-term effect of VAT on household spending using quarter panel data for Visegrad fore countries, as I am focused mostly on the Czech Republic and Slovakia. Then construct a broader set of data for 14 EU countries, in purpose to test the long-term effect. For testing, I use several estimation techniques for panel data, taking into account the dynamic nature of these data sets.

The CEO and CFO are the two key executives of a firm. They work cohesively to ensure the growth of the firm. After the adoption of the Sarbanes Oxley Act (SOX) in 2002, the importance of CFOs has increased due to their personal legal obligation in certifying the accuracy of financial statements. Only a few papers such as Mian (2001), Fee and Hadlock (2004), and Geiger and North (2006) focus on CFOs in the pre-SOX era. However, a vacuum exists in research focusing exclusively on CFOs in the post-SOX era. The purpose of this dissertation is to delve into a comprehensive investigation of the CFOs. More specifically, I answer three questions: a) does the CEO change lead to the CFO change? b) does the CFO appointment type affect the firm’s debt-equity choice? and c) does the CFO appointment affect the firm’s information environment? I use Shumway’s (2001) dynamic hazard model in answering question ‘a’. For question ‘b’, I use instrumental variable (IV) regression under various estimation techniques to control for endogeneity. For part ‘c’, I use the cross sectional difference-in-difference (DND) methodology by pairing treatment firms with control firms chosen by the propensity scores matching (PSM). I find there is about a 70% probability of CFO replacement after the CEO replacement. Both of their replacements are affected by prior year’s poor performance. In addition, as a custodian of the firm’s financial reporting, the CFO is replaced proactively due to a probability of restatement of earnings. I find firms with internal CFO hires issue more equity in the year of appointment than firms with external hires. The promoted CFO significantly improves the firm’s overall governance which helps the firm obtain external financing from equity issue. However, I find that CFO turnover does not significantly affect the firm’s information environment. To ensure that my finding is not due to mixing up of samples of good and distressed firms together, I separated distressed firms and re-ran my models and my finding still holds. This dissertation fills the gap in the literature with regards to CFOs and their post SOX relationship with the firm.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Trabalhos recentes mostraram que a teoria assintÃtica traz resultados equivocados nos testes de causalidade quando o MÃtodo de Momentos Generalizados (MGM) à utilizado. Este estudo re-examina a relaÃÃo dinÃmica entre receitas prÃprias, despesas correntes e transferÃncias correntes para os governos municipais brasileiros no perÃodo de 2000 a 2008. A estimaÃÃo do modelo de dados em painel dinÃmico à feita atravÃs do MGM, mas os testes de especificaÃÃo utilizam valores crÃticos gerados por bootstrap para fornecer melhor aproximaÃÃo à distribuiÃÃo da estatÃstica de teste. Uma defasagem de dois anos à encontrada na equaÃÃo de despesas, mas nenhuma dinÃmica à observada nas equaÃÃes de receitas prÃprias e de transferÃncias, sugerindo a hipÃtese de que receitas passadas afetam despesas correntes
Recent works has shown that the asymptotic theory provides misleading results in causality tests when the Generalized Method of Moments (GMM) is used. This study re-examines the dynamic relationship between own revenues, current expenditures and current grants to municipal governments in Brazil in the period 2000 to 2008. The dynamic panel data model estimation is done by GMM, but the specification tests use bootstrap critical values to provide a better approximation to the distribution of the test statistic. A lag of two years is found in the expenditure equation, but no dynamics is observed in the own revenues and transfers equations, suggesting the hypothesis that past revenues affect current expenditures

L'éolienne Darrieus connaît un intérêt accru ces dernières années parce qu'elle représente une solution alternative potentielle de production d'électricité dans les milieux urbains. En particulier,une éolienne de forte solidité peut être choisie car certaines de ses propriétés peuvent être avantageuses pour son implantation proche de zones habitées. A l'inverse, certaines difficultés aérodynamiques émergent. Ce type d'éolienne fonctionne à de faibles vitesses réduites pour lesquelles le décrochage dynamique a un rôle très significatif. L'objectif de ce travail de thèse consiste à compléter la connaissance du phénomène de décrochage dynamique sur une éolienne à axe vertical afin d'améliorer les modèles numériques de prédiction existants. Cette étude s'appuie sur une analyse combinée de résultats numériques et expérimentaux. Les simulations numériques sont produites avec une méthode des panneaux bidimensionnelle instationnaire. Les effets de la viscosité sont introduits par des corrections utilisant notamment un modèle semi-empirique de décrochage dynamique. Le travail expérimental s'est concentrée sur la dynamique tourbillonnaire à proximité immédiate du rotor résultante du décrochage dynamique. Le montage se compose d'une éolienne à pale droite placée dans une soufflerie. Des mesures instationnaires de la répartition de pression pariétale le long de la corde et des mesures de champ de vitesse par vélocimétrie par images de particules ont été accomplies. Les résultats révèlent la manière dont les caractéristiques du décrochage dynamique sont conditionnées par la vitesse réduite. Le retard au décrochage, l'intensité de l'effet du tourbillon de décrochage dynamique et sa convection ont été quantifiés. Enfin, un examen critique de l'applicabilité du modèle de Leishman-Beddoes pour simuler efficacement les effets du décrochage dynamique a été réalisé
The Darrieus wind turbine has entered a period of renewed interest over the last years because it may stand for an alternative solution to produce electricity in urban areas. In particular, high solidity wind turbine can be chosen to take benefit from some of its key properties for use near populated city areas. Conversely, some aerodynamic problems arise. This type of wind turbine operates at low tip speed ratio for which dynamic stall has a very significant role. The goal of this work is to provide valuable data to complement the knowledge of the dynamic stall phenomenon that occurs on a vertical axis wind turbine in order to improve existing numerical models. This study relies on a combined analysis of numerical and experimental results. The numerical simulations are based on a bidimensional unsteady vortex panel method. Effects of viscosity are introduced by adding corrections computed with a semi-empirical dynamic stall model. The experimental work focuses on the dynamics of the shed vortices existing in the vicinity of the rotor as a result of dynamic stall. The set-up consists of a straight-bladed wind turbine tested in a wind tunnel. Unsteady pressure distribution measurements along the chord and velocity fields measurements by particle image velocimetry were carried out. Results indicate how the characteristics of dynamic stall are conditioned by the tip speed ratio. Stall inception delay, magnitude of the dynamic stall vortex effects and its convection velocity were evaluated. Blade/Vortex interaction was analyzed through the observation of the vortical system downstream of the rotor. In addition, a critical review of the suitability of the Leishman-Beddoes model to effectively simulate the effects of dynamic stall was accomplished

Les éoliennes offshore modernes ont atteint ces dernières années de très grandes dimensions, qui ne cessent d’augmenter en vue de diminuer les coûts de production de l’électricité. Des designs innovants sont alors nécessaires afin d’améliorer les performances aérodynamiques et de réduire les charges structurelles. Les outils de l’état de l’art tels que la théorie de l’élément de pale couplée à la méthode de la quantité de mouvement (BEMT en anglais), utilisés pour la prédiction des charges et performances des rotors, ont été conçus pour des rotors de plus faibles dimensions et dans des conditions standards d’utilisation. Des conditions particulières comme les cas de désalignement du rotor par rapport à l’axe du vent sont a priori hors du domaine de validité des outils de l'état de l'art. Le but de cette thèse est d'étudier des modèles aérodynamiques plus poussés et de les comparer avec les outils de l'état de l'art sur des cas spécifiques. Les écoulements instationnaires sont particulièrement intéressants puisque difficiles à simuler avec les méthodes standards. Ainsi, un code de méthode des panneaux prenant en compte les phénomènes visqueux tels que le décrochage dynamique est comparé à un code BEMT dans des conditions de vent réalistes et avec un fort désalignement du rotor. Les calculs sont réalisés dans le cadre d'un couplage aéro-servo-élastique de manière à être le plus représentatif possible des calculs de chargement effectués dans l'industrie et nécessaires pour la certification des machines. L'impact du modèle de décrochage dynamique est étudié avec les deux méthodes, pour des cas de chargement extrêmes et en fatigue avec désalignement du rotor. Des différences ont été observées entre les deux méthodes et avec plusieurs paramétrisations du modèle de décrochage dynamique. De plus, la prise en compte du couplage servo-élastique modifie les observations faites sur les comparaisons aérodynamiques. De plus, les angles d'attaque observés sur les pales en cas de fort désalignement sont très élevés. L'écoulement autour de profils dans ces conditions est dominé par des effets visqueux non capturés par les méthodes des panneaux ou de BEMT mais modélisés via des modèles semi-empiriques. Des modèles alternatifs doivent donc être utilisés pour mieux prédire de tels phénomènes. Dans la seconde partie de cette thèse l'écoulement autour de profils aérodynamiques d'éoliennes, plus épais que dans l'aéronautique, est étudié à l'aide de Simulation aux Grandes Échelles avec loi de paroi. Plusieurs cas d'écoulement attachés et détachés sont simulés, pour des profils fixes et oscillants. De très grands angles d'attaque sont également simulés, jusqu'à 90°, à un nombre de Reynolds réaliste. Dans les cas attachés et très fortement détachés, la Simulation aux Grandes Échelles avec loi de paroi est capable de capturer correctement l'écoulement avec des maillages peu raffinés. Cependant les cas proches du décrochage se sont révélés plus difficiles à obtenir, et nécessitent des maillages très fins même en utilisant des lois de paroi adéquates. Enfin, des cas oscillants avec fréquence réduite élevée sont également étudiés et comparés avec d'autres modèles. La Simulation aux Grandes Échelles est alors particulièrement adaptée et donne des résultats prometteurs
The size of modern offshore wind turbine rotors has reached very large dimensions and keeps increasing in order to reduce the cost of electricity. More challenging designs are thus needed to improve the aerodynamic performances and reduce the structural loads. The state-of-the-art tools such as Blade Element Momentum Theory (BEMT) used to predict the loads and performances of wind turbines have been designed for much smaller rotors in standard operating conditions. Load cases in specific conditions such as yaw misalignment are a priori out of the validity range for such tools. The goal of the thesis is to investigate more advanced aerodynamic models in order to assess the differences in load predictions compared to state-of-the-art tools. In particular, this work focuses on unsteady flows which represent a challenge for engineering tools. For this purpose, a panel method code including viscous effects such as dynamic stall is compared to a BEMT code in realistic wind conditions with large yaw misalignment. The calculations are performed in the framework of aero-servo-elasto coupling in order to be represen¬tative of the load calculations performed in industry following certification standards. The impact of the dynamic stall model is investigated in particular for both BEMT and panel method, for extreme and fatigue loading in cases of yaw misalignment. Differences have been observed between both codes and for several parametrizations of dynamic stall model. In addition, it has been noticed that including the servo-elasto coupling changes a lot the observations regarding aerodynamic loading. Large angles of at¬tack are observed on wind turbine blades in yaw misalignment cases, and the flow around blade sections in such conditions is particularly affected by viscous effects such as dynamic stall or vortex shedding which are not inherently solved by panel methods nor BEMT but modeled with semi-empirical models. Alternative models such as Large Eddy Simulation (LES) that would capture these effects have to be considered. Wall-modeled LES (WMLES) is thus used in the second part of this thesis to investigate the flow around wind turbine dedicated airfoils, much thicker than airfoils used in aeronautics. Several cases are simulated, for attached and detached flows and in steady or oscillating cases. Angles of attack up to 90° are investigated at realistic Reynolds number. It appears that WMLES is able to capture correctly the main flow features in attached conditions and at very high angle of attack with coarse meshes. However, the near stall cases are more challenging to capture even with appropriate wall laws and require very fine meshes to be correctly solved. A comparison is also performed for motions with high reduced frequency and compared to other models, revealing the promising capacities of WMLES in such cases

碩士
國立暨南國際大學
國際企業學系
100
This thesis estimates China’s equilibrium exchange rate and misalignment since China announced a shift in exchange rate policy from a simple peg to the US dollar to a basket peg about 11 countries by using the dynamic panel GMM estimators with the period of 1975-2010. We estimate the China’s equilibrium exchange rate based on using the purchasing power parity from Penn World Tables with the consideration of Balassa-Samuelson effect, and the others variables from the theory defining equilibrium exchange rate, including BEER/FEER. Compared panel data (fixed/random) model with dynamic panel GMM Estimators, we find Renminbi is significantly overvalued by 31.3% and undervalued by 52.2% .We concern real exchange rate with not only the persistent but also cause and effect with other Macroeconomic variables.We consider the results of exchange rate misalignment using dynamic panel GMM estimators solving endogeneity problems by lag term of real exchange rate are more reliable and significant. With long term estimation, sign dosen’t change across model specifications. We summarize our findings as follows: 1. The coefficients of lagged real exchange rate are positive (0.61~0.82). 2. Real exchange rate have positive relationship with government operating balance(0.0047~0.0099),and negative relationship with money supply(-0.03~-0.068)；have a positive relationship with capital account openness(0.007~0.03)； Current account with negitive relationship (-0.003~-0.004) 3. With dynamic panel GMM estimators ,we find Renminbi is significantly undervalued by 52.2% .

碩士
國立交通大學
電機與控制工程系所
93
In this thesis, a robust and adaptive Background Subtraction algorithm is proposed and implemented. This system mainly consists of three stages. In the first stage, we build a dynamic background image model based on Gaussian Mixture Model method and estimate the model parameters using Expectation Maximization Algorithm. Then, a hierarchical method with color and gradient statistical information to separate background and foreground is proposed. The parameters of background model are updated according to the results of separation and variation of sequence images so all events happened are recorded in the background model. The changes of environment or moving object may cause brightness variations in background scene. These effects will deteriorate the performance of system. Therefore, a shadow removal algorithm combining long-term model with short-term model is proposed. Lastly, the methods are experimented in various indoor conditions. Discussion and comparison on the results are given.

This paper discusses capital structure theories, with special attention to partial-adjustment model. Strategic waiting theory of IPO firms and its relation to market timing theory are also discussed. Two empirical tests related to capital structure theory are included. First one is a test on the relation between a firm’s strategic waiting behavior in IPO market and its stock return. Second one is on the relation of a firm’s strategic waiting behavior in IPO market and its subsequent capital structure decision.

The study aims to investigate the impact of natural resource wealth on the shadow economy. The theoretical section provides the basis of understanding the nature of two phenomena and discusses the possible transmission channels through which natural resources might influence the shadow economy. Consequently, the key determinants of the shadow economy are examined by static and dynamic models. Natural resource abundance is proxied by natural resource rents. We employ a panel data set for 109 countries for the period from 1996 to 2006. The results reveal that resource wealth is associated with the decrease of the shadow economy. This result is robust for different resource types (durable and non-durable), and the effect is more profound for countries with a low income level. JEL Classification C33, E26, O13 Keywords natural resources, shadow economy, dynamic panel data models, system GMM estimator Title Natural Resource Curse and Shadow Economy: Empirical Evidence

Cette thèse est organisée en trois chapitres. Les deux premiers proposent une approche régularisée pour l’estimation du modèle de données de panel dynamique : l’estimateur GMM et l’estimateur LIML. Le dernier chapitre de la thèse est une application de la méthode de régularisation à l’estimation des élasticités de l’offre de travail en utilisant des modèles de pseudo-données de panel. Dans un modèle de panel dynamique, le nombre de conditions de moments augmente rapidement avec la dimension temporelle du panel conduisant à une matrice de covariance des instruments de grande dimension. L’inversion d’une telle matrice pour calculer l’estimateur affecte négativement les propriétés de l’estimateur en échantillon fini. Comme solution à ce problème, nous proposons une approche par la régularisation qui consiste à utiliser une inverse généralisée de la matrice de covariance au lieu de son inverse classique. Trois techniques de régularisation sont utilisées : celle des composantes principales, celle de Tikhonov qui est basée sur le Ridge régression (aussi appelée Bayesian shrinkage) et enfin celle de Landweber Fridman qui est une méthode itérative. Toutes ces techniques introduisent un paramètre de régularisation qui est similaire au paramètre de lissage dans les régressions non paramétriques. Les propriétés en echantillon fini de l’estimateur régularisé dépend de ce paramètre qui doit être sélectionné parmis plusieurs valeurs potentielles. Dans le premier chapitre (co-écrit avec Marine Carrasco), nous proposons l’estimateur GMM régularisé du modèle de panel dynamique. Sous l’hypothèse que le nombre d’individus et de périodes du panel tendent vers l’infini, nous montrons que nos estimateurs sont convergents and assymtotiquement normaux. Nous dérivons une méthode empirique de sélection du paramètrede régularisation basée sur une expansion de second ordre du l’erreur quadratique moyenne et nous démontrons l’optimalité de cette procédure de sélection. Les simulations montrent que la régularisation améliore les propriétés de l ’estimateur GMM classique. Comme application empirique, nous avons analysé l’effet du développement financier sur la croissance économique. Dans le deuxième chapitre (co-écrit avec Marine Carrasco), nous nous intéressons à l’estimateur LIML régularisé du modèle de données de panel dynamique. L’estimateur LIML est connu pour avoir de meilleures propriétés en échantillon fini que l’estimateur GMM mais son utilisation devient problématique lorsque la dimension temporelle du panel devient large. Nous dérivons les propriétes assymtotiques de l’estimateur LIML régularisé sous l’hypothèse que le nombre d’individus et de périodes du panel tendent vers l’infini. Une procédure empirique de sélection du paramètre de régularisation est aussi proposée. Les bonnes performances de l’estimateur régularisé par rapport au LIML classique (non régularisé), au GMM classique ainsi que le GMM régularisé sont confirmées par des simulations. Dans le dernier chapitre, je considère l’estimation des élasticités d’offre de travail des hommes canadiens. L’hétérogéneité inobservée ainsi que les erreurs de mesures sur les salaires et les revenus sont connues pour engendrer de l’endogéneité quand on estime les modèles d’offre de travail. Une solution fréquente à ce problème d’endogéneité consiste à régrouper les données sur la base des carastéristiques observables et d’ éffectuer les moindres carrées pondérées sur les moyennes des goupes. Il a été démontré que cet estimateur est équivalent à l’estimateur des variables instrumentales sur les données individuelles avec les indicatrices de groupe comme instruments. Donc, en présence d’un grand nombre de groupe, cet estimateur souffre de biais en échantillon fini similaire à celui de l’estimateur des variables instrumentales quand le nombre d’instruments est élevé. Profitant de cette correspondance entre l’estimateur sur les données groupées et l’estimateur des variables instrumentales sur les données individuelles, nous proposons une approche régularisée à l’estimation du modèle. Cette approche conduit à des élasticités substantiellement différentes de ceux qu’on obtient en utilisant l’estimateur sur données groupées.
This thesis is organized in three chapters. The first two chapters propose a regularization approach to the estimation of two estimators of the dynamic panel data model : the Generalized Method of Moment (GMM) estimator and the Limited Information Maximum Likelihood (LIML) estimator. The last chapter of the thesis is an application of regularization to the estimation of labor supply elasticities using pseudo panel data models. In a dynamic panel data model, the number of moment conditions increases rapidly with the time dimension, resulting in a large dimensional covariance matrix of the instruments. Inverting this large dimensional matrix to compute the estimator leads to poor finite sample properties. To address this issue, we propose a regularization approach to the estimation of such models where a generalized inverse of the covariance matrix of the intruments is used instead of its usual inverse. Three regularization schemes are used : Principal components, Tikhonov which is based on Ridge regression (also called Bayesian shrinkage) and finally Landweber Fridman which is an iterative method. All these methods involve a regularization parameter which is similar to the smoothing parameter in nonparametric regressions. The finite sample properties of the regularized estimator depends on this parameter which needs to be selected between many potential values. In the first chapter (co-authored with Marine Carrasco), we propose the regularized GMM estimator of the dynamic panel data models. Under double asymptotics, we show that our regularized estimators are consistent and asymptotically normal provided that the regularization parameter goes to zero slower than the sample size goes to infinity. We derive a data driven selection of the regularization parameter based on an approximation of the higher-order Mean Square Error and show its optimality. The simulations confirm that regularization improves the properties of the usual GMM estimator. As empirical application, we investigate the effect of financial development on economic growth. In the second chapter (co-authored with Marine Carrasco), we propose the regularized LIML estimator of the dynamic panel data model. The LIML estimator is known to have better small sample properties than the GMM estimator but its implementation becomes problematic when the time dimension of the panel becomes large. We derive the asymptotic properties of the regularized LIML under double asymptotics. A data-driven procedure to select the parameter of regularization is proposed. The good performances of the regularized LIML estimator over the usual (not regularized) LIML estimator, the usual GMM estimator and the regularized GMM estimator are confirmed by the simulations. In the last chapter, I consider the estimation of the labor supply elasticities of Canadian men through a regularization approach. Unobserved heterogeneity and measurement errors on wage and income variables are known to cause endogeneity issues in the estimation of labor supply models. A popular solution to the endogeneity issue is to group data in categories based on observable characteristics and compute the weighted least squares at the group level. This grouping estimator has been proved to be equivalent to instrumental variables (IV) estimator on the individual level data using group dummies as intruments. Hence, in presence of large number of groups, the grouping estimator exhibites a small bias similar to the one of the IV estimator in presence of many instruments. I take advantage of the correspondance between grouping estimators and the IV estimator to propose a regularization approach to the estimation of the model. Using this approach leads to wage elasticities that are substantially different from those obtained through grouping estimators.

碩士
大葉大學
管理學院碩士在職專班
100
In this paper we investigate the dyanmic relationship between stock prices and exchange rates among Japan and three emerging economies: Korea, Singapore and Taiwan. Daily data spanned from 1996/3/8 to 2011/3/10 are used. We employ the Panel VAR approach to estimate the panel data model. Furthermore, the causal relationship between stock prices and exchange rates is tested carefully. Evidence based on the data from the four Asian economies indicates that in the short run there is uni-directional causality from stock prices to exchange rates. Our finding emphasizes important implications for policy makers of these governments.

El proceso de apertura comercial experimentado por Argentina en los años 90 sometió a la industria por primera vez en mucho tiempo a la competencia externa. Este trabajo investiga en qué medida la competencia externa potencial actuó como un limitante del poder de mercado de la industria local. Utilizando modelos dinámicos para datos en panel se demostró que dicha competencia fue significativa durante el período 1995-2001. En particular, algunos de los modelos estimados sugieren que aquellas industrias menos concentradas, con menor protección arancelaria, con economías de escala más reducidas, no vinculadas directamente a la actividad agropecuaria o que producen productos menos diferenciados son las que enfrentaron una competencia potencial externa significativa.
The process of trade liberalization experienced by Argentina in the 90s subjected domestic industries to foreign competition for the first time in many years. This paper studies to what extent potential foreign competition was a limiting factor of domestic market power. Using dynamic panel data models, this paper shows that such competition was significant between 1995 and 2001. Specifically, some of the models suggest that those industries not directly linked to agricultural activities, with a low degree of concentration, with low tariff barriers, with a low degree of economies of scale and whose output has a low degree of differentiation are the ones that experienced significant potential foreign competition.
Una versión de este trabajo obtuvo el premio "Elías Salama" otorgado en las X Jornadas de Economía Monetaria e Internacional, organizadas por el Departamento de Economía de la Universidad Nacional de La Plata.

Foreign aid has been used on the one hand by donors as an important international relations policy tool and on the other hand by developing countries as a source of funds for development. Since its inception in the 1940s, foreign aid has been one of the most researched topics in development economics. This study adds to this growing aid effectiveness literature, with a particular focus on the under-researched relationship between foreign aid and extreme poverty. The main empirical assessment is based on a sample of 120 developing countries from 1981 to 2013. The study had two main objectives, namely: (i) to estimate the impact of foreign aid on poverty reduction and (ii) to examine the direction of causality between foreign aid and poverty in developing countries. From these two broad objectives, there are six specific objectives, which include to: (i) examine the overall impact of foreign aid (total official development assistance) on extreme poverty, (ii) investigate the impact of different proxies of foreign aid on the three proxies of extreme poverty, (iii) assess whether political freedom (democracy) or economic freedom enhances the effectiveness of foreign aid, (iv) compare the impact of foreign aid on extreme poverty by developing country income groups, and (v) examine the direction of causality between extreme poverty and foreign aid. To achieve these objectives, the study employed two main dynamic panel data econometric estimation methods, namely the systemgeneralised method of moments (SGMM) technique and the panel vector error correction model (VECM) Granger causality framework. While the SGMM was used to assess the impact of foreign aid on extreme poverty, the panel VECM Granger causality was used to examine the direction of causality between foreign aid poverty. The SGMM was used because of its ability to deal with endogeneity by controlling for simultaneity and unobserved heterogeneity, whereas the panel VECM was preferred because the variables were stationary and cointegrated.
Economics
D. Phil. (Economics)

The present study aims to deliberate over a wider perspective on the topic of physical currency, assuming the global conversion to digital payment instruments affecting stakeholders at different scales alters number of aspects. The theoretical section discusses the process of transition to cashless society by identifying transformation stages and the barriers faced to undertake the shift. Subsequently, the links between factors as business environment, globalization, and shadow economy in relation to physical currency in circulation are examined by static and dynamic panel data analyses applying annual panel data for 70 countries for the period from 2013 to 2017. The conclusive inference is formulated based on outputs from the Blundell-Bond (1998) system GMM estimator. The empirical results provide significant evidence on negative relationship between business environment and physical currency in circulation and contrary positive link for shadow economy. Further, the greater impact of business environment on physical money among variables included, implies the promotion of electronic money solutions solely to be not sufficient to transit to cashless economy. We also construct transformation score ranking for the last five years to snap the transit stage among countries included in the study with...