No description available.

Reinforcement learning (RL) algorithms aim to identify optimal action sequences for an agent in a given environment, traditionally maximizing the expected rewards received from the environment by taking each action and transitioning between states. This thesis explores approaching RL distributionally, replacing the expected reward function by the full distribution over the possible rewards received, known as the value distribution. We focus on the quantile regression distributional RL (QR-DQN) algorithm introduced by Dabney et al. (2017), which models the value distribution by representing its quantiles. With such information of the value distribution, we modify the QR-DQN algorithm to enhance the agent's risk sensitivity. Our risk-averse algorithm is evaluated against the original QR-DQN in the Atari 2600 and in the Gymnasium environment, specifically in the games Breakout, Pong, Lunar Lander and Cartpole. Results indicate that the risk-averse variant performs comparably in terms of rewards while exhibiting increased robustness and risk aversion. Potential refinements of the risk-averse algorithm are presented.

Questa tesi utilizza metodologie differenti al fine di esplorare argomenti generalmente ascritti all'economia dello sviluppo. Il primo capitolo discute la letteratura sul capitale sociale scomponendolo nel suo componente strutturale, le reti, e cognitivo, la fiducia. Ogni componente è a sua volta scomposto in diverse sotto-dimensioni una delle quali, il particolarismo, è utilizzato nel secondo capitolo, sia a livello teorico che empirico, come determinante di forme di corruzione collusiva. Come previsto dalla teoria, il particolarismo ha un effetto positivo e causale sulla probabilità di offrire una tangente. Il terzo capitolo valuta l'impatto di un progetto di estensione agricola realizzato in Etiopia, volto ad introdurre la coltivazione di nuovi prodotti ortofrutticoli insieme ad alcune tecniche e strumenti innovativi. Empiricamente si utilizzano gli strumenti della valutazione d’impatto combinando confronti tra villaggi, attraverso una stima difference-in-differences, con una comparazione all'interno del villaggio usando uno studio controllato randomizzato. I risultati indicano che il progetto ha contribuito alla diversificazione produttiva ma non ha influenzato i ricavi ottenuti dalla vendita dei prodotti ortofrutticoli e, di conseguenza, il benessere delle famiglie. Il quarto capitolo mostra come meccanismi incentivati sufficientemente simili elicitino decisioni correlate in termini di avversione al rischio solo quando si tengono in considerazione altri atteggiamenti relativi al rischio. Inoltre si studia la correlazione tra l'avversione al rischio riportata e l'avversione al rischio ottenuta tramite lotterie. I risultati suggeriscono una misurata validità esterna dei due metodi studiati. / This dissertation makes use of several methodologies to explore topics ascribed to the field of development economics. Chapter 1 reviews the literature on social capital by presenting a decomposition of trust and networks -- the cognitive and the structural component of social capital, respectively--, in several sub-dimensions. One of this dimension is used in chapter 2 where we investigate, both theoretically and empirically, the role played by the cultural norm of particularism, as opposed to universalism, for collusive bribery. Consistent with the theory, particularism is found to have a positive causal effect on the probability of offering a bribe. Chapter 3 assesses the impact of a small-scale agricultural extension project implemented in rural Ethiopia aimed at introducing the cultivation of horticultural gardens. Empirically, a mixed impact evaluation design is used combining across-villages comparisons, through difference-in-differences estimations, with a within village randomized control trial. The findings indicate that the project contributes to production diversification while it does not influence total revenues from sales, household welfare and diet. Chapter 4 shows that similar incentivized mechanisms elicit similar decisions in terms of monetary risk aversion only if other risk-related attitudes are accounted for. Furthermore, it examines whether individuals' characteristics and a self-assessed measure of risk aversion relate to individuals' choices in lotteries. The findings suggest that there is some external validity of the two studied tasks as predictors of self-reported risk attitudes.

Syfte: Den 9:e september föregående år uppdagade Sveriges Television att den socialdemokratiska regeringen har lagt fram en proposition till Riksdagen gällande kvotering i börsbolagsstyrelser. I propositionen föreslås att svenska börsbolagsstyrelser ska bestå av minst 40 procent kvinnor. • Syftet med denna studie är att undersöka om det finns ett statistiskt samband mellan andelen kvinnor i svenska börsbolagsstyrelser och kapitalstrukturen, samt om det finns ett statistiskt samband mellan kapitalstrukturen och om bolagets VD är kvinna. Metod: En kvantitativ metod med en deduktiv ansats har tillämpats. Data har samlats in från svenska börsbolags årsredovisningar från bokslutsåret 2015. Datan har använts för att bygga upp relevanta variabler som sedan har testats i en multivariat regressionsanalys. Resultat & slutsats: På frågan om kvinnor påverkar kapitalstrukturen vill vi mena att resultatet av denna studie tyder på att svaret är nej. Resultatet ger belägg för att det inte finns något samband mellan andelen kvinnor i styrelsen och kapitalstrukturen men att det råder ett mycket svagt positivt samband mellan en kvinnlig VD och kapitalstrukturen. Förslag till fortsatt forskning: Den främsta begränsningen för denna undersökning är att hänsyn endast har tagits till ett bokslutsår, till skillnad från många tidigare vetenskapliga studier som har baserat undersökningarna på flera bokslutsår. Förslag till vidare forskning är således att genomföra denna undersökning över flera bokslutsår för att ta hänsyn till eventuella mönster i finansieringsbeslut. Den kvantitativa metoden bidrar med data som kan användas för att påvisa ett statistiskt samband. Ett annat förslag till fortsatt forskning är att genomföra samma studie fast tillämpa en kvalitativ metod för att analysera skillnader i finansieringsbeslut av män och kvinnor som verkställande direktörer och styrelsemedlemmar. Uppsatsens bidrag: Denna undersökning har bidragit med teoretisk kunskap om faktorer som påverkar kapitalstrukturen samt med praktisk kunskap om hur en eventuell kvoteringslag kan komma att påverka kapitalstrukturen. / Title: Does women in the boardroom affect the capital structure? – An analysis if there is a correlation between the proportion of women in the boardroom and the capital structure and between a female CEO and the capital structure. Aim: On September 9 last year, Sveriges Television revealed that the socialistic government has presented a proposition to the parliament concerning quotas in listed companies’ boards. The proposition proposes that boards in Swedish listed firms’ should consist of at least 40 percent women. • The purpose of this study is to investigate if there is a statistical correlation between the proportion of women on the boards of Swedish listed companies and the capital structure, and if there is a statistical correlation between the capital structure and if the company’s CEO is a woman. Method: A quantitative method with a deductive approach has been applied. Data has been collected from the Swedish listed companies’ annual financial reports from the year 2015. The data has been used to build up relevant variables, which has then been tested in a multivariate regression analysis. Result & Conclusions: On the question if women affect the capital structure, we would like to think that the result of this study indicates the answer is no. The result provides evidence that there is no statistical correlation between the proportion of women on the board and the capital structure but that there is a marginal positive correlation between a female CEO and the capital structure. Suggestions for future research: The main limitation for this study is that consideration has only been given to one fiscal year, unlike many previous studies that have based the surveys on several fiscal years. Suggestion for further research is to implement this study on several fiscal years to account for any potential patterns in the financing decisions. The quantitative method contributes with data that can be used to detect a statistical relationship. Another suggestion for further research is to accomplish the same study, but apply a qualitative method to analyze the differences in financing decisions by men and women as CEOs and board members. Contribution of the thesis: This study has provided theoretical knowledge of factors affecting the capital structure as well as practical knowledge about how a possible quota law may affect the capital structure.

Desde o trabalho de Lucas (1987), diversos autores se dedicaram a medir o custo de bem-estar dos ciclos econômicos. Embora a literatura desse tema para os Estados Unidos seja extensa, há poucos estudos para países em desenvolvimento. O objetivo do presente trabalho é estimar este custo para uma amostra de países latino-americanos e compará-lo ao custo obtido dos dados da economia dos Estados Unidos. É utilizada a metodologia proposta por Reis (2009), que assume que o consumo segue um processo ARIMA(p,1,q), que tem as ordens selecionadas com base no critério de informação bayesiano. Os resultados obtidos indicam que, sob todos os processos assumidos para as série de consumo, os países latino-americanos possuem custo consideravelmente maior do que o dos Estados Unidos. Entretanto, quando se assume a estrutura ARIMA, a diferença entre os custos dos países latino-americanos e dos Estados Unidos é a menor. / Since the work of Lucas (1987), several authors have dedicated to measure the welfare costs of business cycle. Although the literature on this subject is extensive for the United States, few studies were made considering developing countries data. The objective of this study is to estimate this cost for a sample of Latin American countries and compare it to the cost obtained from the US economy data. The methodology proposed by Reis (2009) is used. It assumes that consumption follows an ARIMA (p,1,q) model, and the p and q orders are selected based on the Bayesian information criterion. The results indicate that, in all processes assumed for the consumption series, Latin American countries have considerably higher welfare costs than the US. However, when the ARIMA structure is assumed, the difference between the costs of Latin American countries and the United States is the smallest.

Nesta tese desenvolvemos modelos de apreçamento de ativos financeiros baseados no conceito de influência social, analisamos também algumas das consequências destes modelos e comparamos com os modelos correspondentes clássicos. Por meio das funções de utilidade generalizadas exponencial e quadrática, deduzimos o CAPM com influência social. Obtivemos que o coeficiente beta da fórmula do CAPM depende de uma aversão ao risco efetiva do mercado que depende da distribuição de riqueza dos agentes do mercado. Supondo que distribuição de riqueza dos agentes do mercado segue uma distribuição de Pareto, fomos capazes de conectar, aversão ao risco média efetiva do mercado, volatilidade e distribuição de riqueza dos agentes, estabelecendo a previsão empírica de que a volatilidade aumenta com a concentração da distribuição de riqueza dos agentes do mercado, a qual foi corroborada por meio de análise estatística. Através da função generalizada tipo potência são feitas algumas considerações sobre alguns \"puzzles\" econômicos bem conhecidos (o \"Equity Premium Puzzle\" e o \"Riskfree Rate Puzzle\") que mostram que a modelagem da influência social pode ter impacto no esclarecimento destes \"puzzles\". / In this thesis we develop pricing models for financial assets based in the concept of social influence, we analyze too some of consequences of this models and we compare with the corresponding classical models. By means of the exponential and quadratic generalized utility functions, we deduce the CAPM with social influence. We obtained that the coefficient beta from the formula of the CAPM depends of a market effective risk aversion that depends of the wealth distribution of the market agents. Supposing that the wealth distribution of the market agents follows a Pareto distribution, we were able to connect, market effective average risk aversion, volatility and wealth distribution of the agents, establishing the empirical forecasting that the volatility grows with the concentration of the wealth distribution of the market agents, which was corroborated by means of statistical analysis. Through the generalized power function are made some considerations about some economic puzzles well-known (the Equity Premium Puzzle and the Riskfree Rate Puzzle) that show us that the modeling of the social influence can to have impact in the clarification these puzzles.

Le but de cette thèse est d'étudier par quatre essais l'économie de migration de pays en voie de développement. Le premier chapitre évalue l'effet des catastrophes naturelles (principalement en raison du changement climatique), dans les pays en voie de développement, sur des taux de migration et regarde comment cet effet varie selon le niveau d'enseignement des personnes. Nos résultats montrent que les catastrophes naturelles sont positivement associées aux taux d'émigration et impliquent aussi la migration des personnes fortement qualifiés. Le deuxième chapitre présente les différents canaux expliquant l'intention de migrer illégalement. Une des nouveautés de l'analyse est qu'elle utilise une enquête sur mesure parmi des individus sénégalais urbains. Nous constatons que les migrants illégaux potentiels sont enclins à accepter un risque substantiel de mort et sont souvent jeunes, célibataires et avec un niveau bas d'éducation. Nous montrons aussi que le prix de l'immigration illégale, les réseaux d'immigrés, de hautes espérances, des politiques d'immigration serrées et le pays de destination jouent tous un rôle dans l'empressement de migrer illégalement. Le troisième chapitre complète le deuxième en étudiant le rôle d'aversion des risques et le taux d'escompte dans la migration illégale du Sénégal. Nos résultats montrent que ces préférences individuelles comptent dans l'empressement de migrer illégalement et payer à un contrebandier. Finalement dans le quatrième chapitre, nous nous sommes intéressés à la place des migrants sur les marchés de crédit dans un contexte rural. Selon nos résultats, avoir un migrant dans un ménage augmente autant la probabilité d'avoir un prêt que sa taille, que le prêt soit formel ou informel. Nous constatons aussi que cet effet positif reste significatif peu importe si le prêt est pris pour des raisons professionnelles ou simplement pour acheter de la nourriture. / The aim of this thesis is to study through four essays the economics of migration from developing countries. The first chapter assesses the effect of natural disasters (mainly due to climate change), in developing countries, on migration rates and looks at how this effect varies according to the level of education of people. Our results show that natural disasters are positively associated with emigration rates and also involve the migration of highly skilled people. The second chapter presents the different channels explaining the intention to migrate illegally. One of the novelties of the analysis is that it uses a tailor-Made survey among urban Senegalese individuals. We find that potential illegal migrants are willing to accept a substantial risk of death and tend to be young, single and with a low level of education. We also show that the price of illegal migration, migrant networks, high expectations, tight immigration policies and the preferred destination country all play a role in the willingness to migrate illegally. The third chapter completes the second one by studying the role of risk-Aversion and discount rate in illegal migration from Senegal. Our results show that these individual preferences matter in the willingness to migrate illegally and to pay a smuggler. Finally in the fourth chapter, we are interested in the effect of migrants on credit markets in a rural Senegalese context. According to our results, having a migrant in a household increases both the likelihood of having a loan and its size, whether the loan is formal or informal. We also find that this positive effect remains significant no matter if the loan is taken for professional activities or simply to buy food.

Il est admis dans les théories économiques que l’existence de risques importants peut être source de sérieuses perturbations au bien-être des ménages et à l’équilibre budgétaire de l’Etat, car les risques ne permettent pas souvent l’optimisation des ressources. En admettant que le risque est un produit d’aléa et de vulnérabilité, nous constatons que l’aléa est souvent considéré au Niger comme l’unique «coupable» de ces perturbations, alors que le comportement des agents face au risque peut en être un facteur déterminant. Sur ce constat, cette thèse se propose d’analyser ces comportements et leurs implications dans les décisions économiques des ménages. Les principaux résultats montrent d’abord une aversion au risque assez relative qui s’explique par deux approches dominantes: une perception fataliste des risques naturels et anthropiques d’une part, et une rationalité adaptative au regard de l’importance de ces risques et de la vulnérabilité des ménages, d’autre part. Cette notion d’aversion a été ensuite utilisée pour servir de lien à l’analyse des risques de comportement inhérents essentiellement à l’asymétrie d’information. Il ressort de cette analyse que face aux risques naturels auxquels les individus paraissent impuissants, ces derniers développent des comportements opportunistes au détriment des contrats de crédit mutuellement avantageux, par un usage abusif de la rente informationnelle. Nous pensons que dans ce cas-ci, la contrainte des incitations doit être sérieusement prise en compte. Par ailleurs, la simultanéité des risques climatiques et d’une forte asymétrie d’information en milieu rural laisse penser que l’assurance agricole indicielle doit être progressivement envisagée. / It is recognized in economic theory that the existence of significant risks can cause serious disruption to the well-being of households and to the State budget’s balance, because the risks do not often value for money. Assuming that the risk is a hazard and vulnerability occurs, we find that the hazard is often seen in Niger as the only "guilty" of these disturbances, while the agents' behavior towards risk can be a factor. On this observation, this thesis proposes to analyze these behaviors and their implications in the economic decisions of households. The main results first show a rather relative risk aversion, which can be explained by two main approaches: a fatalistic perception of natural and man-made hazards on the one hand, and adaptive rationality in terms of the importance of these risks and the vulnerability of households, on the other. This notion of aversion was then used to provide a link to the analysis of risk behavior associated with information asymmetry. It is clear from this analysis, to natural hazards which individuals appear powerless; they are developing opportunistic behavior at the expense of credit agreements mutually beneficial, by abuse of informational rent. We believe that in this case, the incentive constraint must be taken seriously. The simultaneity of climate risk and high information asymmetry rural index suggests that the agricultural insurance should be progressively considered.

Paper [I] theoretically analyzes how the level and uncertainty of future prospects affect incentives to abstain from sexual risk taking in the presence of HIV. The results suggest that, for individuals with limited access to HIV treatment, uncertainty of future health may be an important factor driving unsafe sex practices and support the empirical finding of a weak link between sexual behavior, HIV prevalence, and HIV knowledge in poor countries; therefore suggesting that AIDS policy needs to be calibrated in order to fit within different social contexts. Paper [II] empirically tests the link between uncertainty of future prospects and sexual risk taking in a group of young adults in Cape Town, South Africa. The findings indicate that expected income and health and future uncertainty are significant determinants of current patterns of sexual risk taking. However, the empirical results only provide limited support to a link between expected health and sexual risk taking. Paper [III] theoretically analyzes effects of affect and defensive denial on incentives to engage in sexual risk taking related to HIV. The results of the theoretical analysis suggest that the effect of rationalization of personal risk depends on the risk of being HIV positive. Although rationalization causes excessive risk taking behavior for individuals with a relatively low lifetime risk, it may prevent fatalism among individuals whose lifetime risk of HIV is perceived as overwhelming. Paper [IV] theoretically analyzes the role of identity conflict for the evolution of female labor supply over time. The results suggest the fear of becoming an outsider in society may have prevented a complete transition of women from housewives to breadwinners. In addition, our analysis shows that not recognizing that the weights attached to different social identities are endogenous may imply that the long-run effects on labor supply of a higher wage may be underestimated.

ABSTRACT INFLATION TARGETING AND FISCAL DOMINANCE: EVIDENCE FROM TURKEY SEL, TUgBA M.Sc., Department of Economics Supervisor: Prof. Dr. Erdal &Ouml / zmen September 2007, 60 pages. This study investigates the significance of fiscal dominance for an inflation targeting regime in the context of the recent Turkish experience. To this end, capital flows and country risk equations are estimated for the Turkish monthly data pertaining the inflation targeting regime implementation period. The results from the capital flows models based on portfolio approach strongly suggest that the real effective exchange rates in Turkey during the period are determined by foreign interest rates and the Emerging Markets Bond Index (EMBI) but not by the domestic interest rates in the long run. This supports the view that the risk premium channel dominates the standard portfolio channel in the determination of real exchange rates in Turkey during the period. The country risk of Turkey, proxied by the EMBI spread in the long run is determined by risk appetite of foreign investors and domestic variables including real debt stock, real consolidated budget balance, international gross reserves, current account deficits and credit ratings. All these results are found to be important manifestations of the presence fiscal dominance in Turkey. Consequently, contrary to the postulations of the conventional monetary policy transmission mechanism, interest rate increases to cope with inflationary pressures may lead to an inflation acceleration, rather than the reverse.