79 resultados para expectation maximization
Resumo:
Até recentemente, pesquisas sobre a relação do usuário com o uso de tecnologia focaram sistemas utilitários. Com a popularização dos PCs para uso doméstico e o surgimento da Internet, a interação dos usuários com tecnologia deixou de ser vista apenas de forma utilitária, e passou a ser orientada também ao atendimento de necessidades hedônicas, fazendo com que as pesquisas em Tecnologia e Sistemas de Informação (SI) extrapolassem os limites da empresa. As pesquisas no campo tem dado atenção cada vez maior ao uso de sistemas hedônicos, cujo objetivo é satisfazer necessidades como entretenimento e diversão, ao invés de um valor instrumental. Entre os sistemas hedônicos, um em particular recebe cada vez mais destaque, os videogames. Jogos digitais estão presentes por toda a sociedade, existindo uma crescente adoção, institucionalização e ubiquidade dos videogames na vida diária. A nova geração foi criada com jogos interativos e espera o mesmo tipo de interação nos demais SI. Por serem divertidos e envolventes, organizações de diversos setores estão tentando integrar características dos jogos digitais em sistemas organizacionais, com a expectativa de melhorar a motivação e desempenho dos funcionários e engajar consumidores online. Para analisar a relação do usuário com jogos digitais foram desenvolvidas três pesquisas. A primeira aborda os motivos pelos quais o indivíduo se engaja com o jogo, definindo Engajamento com base em desafio, imersão e curiosidade. Já as motivações dos indivíduos são analisadas pelo divertimento e a competição. A partir do momento em que o indivíduo está engajado, é necessário medir a experiência holística que ele experimenta desta interação. Para tanto, a segunda pesquisa analisa os dois construtos mais utilizados no campo para mensurar tal experiência, Flow e Absorção Cognitiva. A última pesquisa se utiliza dos conceitos explorados nas duas anteriores para desenvolver uma rede nomológica para a predição da intenção comportamental do indivíduo para o uso de jogos digitais. Como resultados temos um esclarecimento sobre os fatores que levam a um comportamento engajado dos jogadores, com maior importância do desafio de dominar o jogo e divertimento em relação a competição com outros jogadores. Outra contribuição é a conclusão que Flow e Absorção Cognitiva, dois dos principais construtos utilizados em SI para medir a experiência hedônica do usuário, não são adequados para mensurar tal experiência para videogames. Por fim existe a proposta de uma rede nomológica em um contexto de utilização de um sistema hedônico interativo, permitindo que novos trabalhos possam se beneficiar.
Resumo:
This paper presents optimal rules for monetary policy in Brazil derived from a backward looking expectation model consisting of a Keynesian IS function and an Augmented Phillips Curve (ISAS). The IS function displays'a high sensitivity of aggregate demand to the real interest rate and the Phillips Curve is accelerationist. The optimal monetary rules show low interest rate volatility with reaction coefficients lower than the ones suggested by Taylor (1993a,b). Reaction functions estimated through ADL and SUR models suggest that monetary policy has not been optimal and has aimed to product rather than inflation stabilization.
Infrastructure privatization in a neoclassical economy: macroeconomic impact and welfare computation
Resumo:
In this paper a competi tive general equilibrium model is used to investigate the welfare and long run allocation impacts of privatization. There are two types of capital in this model economy, one private and the other initially public ("infrastructure"), and a positive extemality due to the latter is assumed. A benevolent governrnent can improve upon decentralized allocation intemalizing the extemality, but it introduces distortions in the economy through the finance of its investments. It is shown that even making the best case for public action - maximization of individuais' welfare, no operation inefficiency and free supply to society of infrastructure services - privatization is welfare improving for a large set of economies. Hence, arguments against privatization based solely on under-investment are incorrect, as this maybe the optimal action when the financing of public investment are considered. When operation inefficiency is introduced in the public sector, gains from privatization are much higher and positive for most reasonable combinations of parameters.
Resumo:
We develop and empirically test a continuous time equilibrium model for the pricing of oil futures. The model provides a link between no-arbitrage models and expectation oriented models. It highlights the role of inventories for the identification of different pricing regimes. In an empirical study the hedging performance of our model is compared with five other one- and two-factor pricing models. The hedging problem considered is related to Metallgesellschaft´s strategy to hedge long-term forward commitments with short-term futures. The results show that the downside risk distribution of our inventory based model stochastically dominates those of the other models.
Resumo:
The inability of rational expectation models with money supply rules to deliver inflation persistence following a transitory deviation of money growth from trend is due to the rapid adjustment of the price level to expected events. The observation of persistent inflation in macroeconomic data leads many economists to believe that prices adjust sluggishly and/or expectations must not be rational. Inflation persistence in U.S. data can be characterized by a vector autocorrelation function relating inflation and deviations of output from trend. In the vector autocorrelation function both inflation and output are highly persistent and there are significant positive dynamic cross-correlations relating inflation and output. This paper shows that a flexible-price general equilibrium business cycle model with money and a central bank using a Taylor rule can account for these patterns. There are no sticky prices and no liquidity effects. Agents decisions in a period are taken only after all shocks are observed. The monetary policy rule transforms output persistence into inflation persistence and creates positive cross-correlations between inflation and output.
Resumo:
Despite the difficulties involved in the precise determination of equilibrium real interest rates, it seems clear that nominal interest rates has been higher in Brazil than in similar emerging economies. This paper aims to shed light on the possible reasons for this feature of the Brazilian economy. We extend Miranda and Muinhos (2003) one-country study to a sample of 20 countries, using many methods to compare measures of the real interest: (i) extracting equilibrium interest rates from IS curves; (ii) extracting steady state interest rates from marginal product of capital; (iii) capturing relevant variables and the fixed effects having real interest rates as dependent variable in a panel for emerging countries; and (iv) extracting inflation expectation from the spread between fixed rate and inflation-indexed treasure notes.
Resumo:
This paper measures the importance of indirect network effects in the adoption by colleges and students of ENEM, a standardized exam for high-school students in Brazil that can be used in college application processes. We estimate network effects and find that they are economically significant. Students are more likely to take ENEM the larger the number of colleges adopting it. Similarly, colleges are more likely to adopt it the larger the number of students taking the exam. Moreover, we find evidence that colleges play strategically and that heterogeneity determines their decisions. A college is less likely to adopt ENEM the larger the number of competitors adopting it. Colleges’ characteristics such as ownership and organization affect adoption decisions. In a counterfactual exercise we compare colleges’ adoption decisions under competition and under joint colleges’ payoffs maximization. Adoption rates are significantly reduced when colleges internalize the competitive effect, i.e., the effect of their decisions on other colleges’ payoffs. On the other hand, they increase when indirect network effects - the effect of students’ response to their decisions on other colleges’ payoffs - are also internalized. Competitive adoption rates are found to exceed joint optimum rates by a small difference. These results suggest that, without considering students’ welfare, adoption rates are excessive, but close to the joint optimum.
Resumo:
O objetivo dessa dissertação é analisar como evolui a relação entre os sócios em uma sociedade anônima de capital fechado, à medida que suas expectativas e posicionamentos em termos de estratégia se modificam ao longo do tempo. Tendo como referência a governança corporativa, o estudo constrói uma revisão da relação principal-principal em uma empresa subsidiária criada para um propósito específico com a participação de grandes grupos multinacionais.
Resumo:
Our focus is on information in expectation surveys that can now be built on thousands (or millions) of respondents on an almost continuous-time basis (big data) and in continuous macroeconomic surveys with a limited number of respondents. We show that, under standard microeconomic and econometric techniques, survey forecasts are an affine function of the conditional expectation of the target variable. This is true whether or not the survey respondent knows the data-generating process (DGP) of the target variable or the econometrician knows the respondents individual loss function. If the econometrician has a mean-squared-error risk function, we show that asymptotically efficient forecasts of the target variable can be built using Hansens (Econometrica, 1982) generalized method of moments in a panel-data context, when N and T diverge or when T diverges with N xed. Sequential asymptotic results are obtained using Phillips and Moon s (Econometrica, 1999) framework. Possible extensions are also discussed.
Resumo:
This work aims to analyze the interaction and the effects of administered prices in the economy, through a DSGE model and the derivation of optimal monetary policies. The model used is a standard New Keynesian DSGE model of a closed economy with two sectors companies. In the first sector, free prices, there is a continuum of firms, and in the second sector of administered prices, there is a single firm. In addition, the model has positive trend inflation in the steady state. The model results suggest that price movements in any sector will impact on both sectors, for two reasons. Firstly, the price dispersion causes productivity to be lower. As the dispersion of prices is a change in the relative price of any sector, relative to general prices in the economy, when a movement in the price of a sector is not followed by another, their relative weights will change, leading to an impact on productivity in both sectors. Second, the path followed by the administered price sector is considered in future inflation expectations, which is used by companies in the free sector to adjust its optimal price. When this path leads to an expectation of higher inflation, the free sector companies will choose a higher mark-up to accommodate this expectation, thus leading to higher inflation trend when there is imperfect competition in the free sector. Finally, the analysis of optimal policies proved inconclusive, certainly indicating that there is influence of the adjustment model of administered prices in the definition of optimal monetary policy, but a quantitative study is needed to define the degree of impact.
Resumo:
Bali, Cakici e Chabi-Yo (2011) introduziram uma nova medida de risco, englobando as medidas de risco de Aumann e Serrano (2008) e Foster e Hart (2009). Trata-se de um modelo de medida de risco implícito de opções baseado na distribuição neutra ao risco dos retornos de ativos financeiros. Este trabalho se propõe a calcular a medida de risco de Bali, Cakici e Chabi-Yo (2011) com base nas opções de petróleo, a commodity mais importante da economia mundial. Como os preços das opções incorporam a expectativa do mercado, a medida de risco calculada é considerada forward-looking. Desta forma, esse trabalho também analisa a significância dessa medida em prever a atividade econômica futura. Os resultados indicaram poder preditivo em relação ao índice VIX, o qual representa a incerteza do mercado financeiro, e ao índice CFNAI, indicador da atividade econômica norte-americana.
Resumo:
Recent regulatory efforts aim at lowering the cyclicality of bank lending because of its potential detrimental effects on financial stability and the real economy. We investigate the cyclicality of SME lending by local banks with vs. without a public mandate, controlling for location, size, loan maturity, funding structure, liquidity, profitability, and credit demand-side factors. The public mandate is set by local governments and stipulates a deviation from strict profit maximization and a sustainable provision of financial services to local customers. We find that banks with a public mandate are 25 percent less cyclical than other local banks. The result is credit supply-side driven and especially strong for savings banks with high liquidity and stable deposit funding. Our findings have implications for the banking structure, financial stability and the finance-growth nexus in a local context.
Resumo:
In the 1970s, Corporate Social Responsibility (CSR) was discussed by Nobel laureate Milton Friedman in his article “The Social Responsibility of Business Is to Increase Its Profits.” (Friedman, 1970). His view on CSR was contemptuous as he referred to it as “hypocritical window-dressing” a reflection of the view of Corporate America on CSR back then. For a long time short-term maximization of shareholder value was the only maxim for top management across industries and companies. Over the last decade, CSR has become a more important and relevant factor of a company’s reputation, shifting the discussion from whether CSR is necessary to how best CSR commitments should be done (Smith, 2003). Inevitably, companies do have an environmental, social and economic impact, thereby imposing social costs on current and future generations. In 2013, 50 of the world biggest companies have been responsible for 73 percent of the total carbon dioxide (CO2) emission (Global 500 Climate Change Report 2013). Post et al. (2002) refer to these social costs as a company’s need to retain its “license to operate”. In the late 1990s, CSR reporting was nearly unknown, which drastically changed during the last decade. Allen White, co-founder of the Global Reporting Initiative (GRI), said that CSR reporting”… has evolved from the extraordinary to the exceptional to the expected” (Confino, 2013). In confirmation of this, virtually all of the world’s largest 250 companies report on CSR (93%) and reporting by now appears to be business standard (KPMG, 2013). CSR reports are a medium for transparency which may lead to an improved company reputation (Noked, 2013; Thorne et al, 2008; Wilburn and Wilburn, 2013). In addition, it may be used as part of an ongoing shareholder relations campaign, which may prevent shareholders from submitting Environmental and Social (E&S)1 proposals (Noked, 2013), based on an Ernst & Young report 1 The top five E&S proposal topic areas in 2013 were: 1. Political spending/ lobbying; 2. Environmental sustainability; 3. Corporate diversity/ EEO; 4.Labor/ human rights and 5. Animal testing/ animal welfare. Three groups of environmental sustainability proposal topics of sub-category number two (environmental sustainability) 6 2013, representing the largest category of shareholder proposals submitted. PricewaterhouseCoopers (PwC) even goes as far as to claim that CSR reports are “…becoming critical to a company’s credibility, transparency and endurance.” (PwC, 2013).
Resumo:
A presente dissertação investiga a utilização de medidas como a adesão automática pela regulação da previdência complementar fechada a partir da flexibilização do conceito de racionalidade, tendo como base a Análise Econômica e Comportamental do Direito. Inicia-se o trabalho pela evolução histórica da regulação da previdência no Brasil, avaliando os impactos sistêmicos das alterações ocorridas no primeiro pilar previdenciário (regimes básicos). Em virtude dessas alterações e do crescimento da relevância do segundo pilar de previdência social (Previdência Complementar Fechada) para a manutenção do bem-estar, analisa-se a possibilidade de ocorrência de vieses cognitivos que implicam desvios de racionalidade dos indivíduos nas decisões relativas à previdência complementar. Esses vieses cognitivos podem fazer com que indivíduos escolham alternativas que não maximizam seu bem-estar, por razões como inércia, procrastinação e superotimismo, ao contrário do que aponta o pressuposto de racionalidade da Economia Neoclássica. Os resultados analisados conduzem à necessidade de adoção de medidas regulatórias capazes de mitigar esses desvios de racionalidade, na forma de adoção de arquitetura de escolhas que induzam à maximização do bem-estar individual, sem limitar a liberdade individual dos envolvidos. Essas medidas, entretanto, especialmente a adesão automática aos planos de benefícios, destinam-se à mitigação de vieses cognitivos, sendo criticável sua adoção em planos de previdência onde observa-se predominância de outras razões para baixos níveis de adesão, como desconfiança em relação à gestão do plano. Ademais, faz-se necessário respeitar certos critérios para sua implementação, a fim de garantir que esse instrumento somente seja utilizado quando se observar vieses cognitivos que prejudiquem significativamente o bem-estar, bem como que a opção à qual os indivíduos estão sendo induzidos é vantajosa, ao menos na grande maioria das vezes. Ao final, verifica-se a juridicidade dessas medidas, à luz da proporcionalidade, norma que permite identificar os limites para a intensidade regulatória.
Resumo:
Recent regulatory efforts aim at lowering the cyclicality of bank lending because of its potential detrimental effects on financial stability and the real economy. We investigate the cyclicality of SME lending by local banks with vs. without a public mandate, controlling for location, size, loan maturity, funding structure, liquidity, profitability, and credit demand-side factors. The public mandate is set by local governments and stipulates a deviation from strict profit maximization and a sustainable provision of financial services to local customers. We find that banks with a public mandate are 25 percent less cyclical than other local banks. The result is credit supply-side driven and especially strong for savings banks with high liquidity and stable deposit funding. Our findings have implications for the banking structure, financial stability and the finance-growth nexus in a local context.