ABSTRACT In Brazil, graduate courses are evaluated by the National Graduate Program System and regulated by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), an agency linked to the Ministry of Education (MEC). The intellectual production of the faculty of the programs is the main criteria in determining a program’s grade. In this study, we verified whether the grade attributed to the programs is dependent on the co-authorship network of the faculty of the program. Particularly, we analyze whether programs composed mostly by faculty members who cooperate in academic productions and have a more central position in the co-authorship network perform better than those with faculty with fewer collaboration. The paper concludes that there is a relation between the programs’ grade and the number of faculty members that collaborates in their intellectual productions. It is also concluded that programs that improved the grade are composed mainly of faculty members with high centrality or have few faculty members with low centrality measures. Moreover, programs that have decreased their grade are formed mainly by faculty members with low centrality measures or with few faculty members with high centrality measures.

Resumo Concluiu-se que, pela regra do fator previdenciário, as alíquotas vigentes são insuficientes para cobertura dos benefícios previdenciários, uma vez que as alíquotas atuarialmente justas são 30,69% e 35,27% para homens e mulheres, respectivamente. Contudo, caso a reforma da Previdência fosse aprovada em seu texto original, os percentuais justos seriam reduzidos para 22,25%, e 21,60%, respectivamente. Além da idade mínima, grande parte dessa redução deve-se às regras propostas para cálculo da pensão, que admitem valor abaixo do salário mínimo. Esses resultados atenderam ao objetivo deste trabalho, que foi comparar as alíquotas previdenciárias atuarialmente justas para o Regime Geral de Previdência Social, tendo como base as regras do fator previdenciário e da proposta de idade mínima, presente na Proposta de Emenda à Constituição n. 287/2016. As mudanças demográficas ocorridas no Brasil nos últimos anos chamam a atenção para a questão da sustentabilidade do sistema previdenciário nacional, e aprovar a reforma previdenciária tem sido prioridade do governo. Logo, é indiscutível a necessidade de um estudo atuarial que viesse calcular alíquotas atuarialmente justas e comparar o atual cenário com as propostas de reforma. Utilizaram-se modelos atuariais com múltiplos decrementos para o cálculo das alíquotas justas, considerando uma família padrão [funcionário(a) de 25 anos, cônjuge e dois filhos], sendo o homem três anos mais velho que a mulher. Adotaram-se como premissas biométricas as tábuas IBGE 2015 - Extrapolada (mortalidade) e Álvaro Vindas (invalidez), a taxa real de crescimento salarial de 2% a.a. e a taxa real de juros de 3% a.a.

Abstract It has been shown that under the social security factor rule current contribution rates are insufficient to cover social security benefits, since the actuarially fair rates are 30.69% and 35.27% for men and women, respectively. However, if the social security reform were approved as submitted, the fair rates would be reduced to 22.25% and 21.60%, respectively. Besides the minimum age, part of this reduction is due to the proposed rules allowing pension values lower than the minimum wage. These results served the objective of this work, which was to compare the actuarially fair social security rates for the General Social Welfare Policy (GSWP), based on the social security factor rules and the minimum age proposal present in Proposed Constitutional Amendment n. 287/2016. The demographic changes that have taken place in Brazil in recent years raise questions about the sustainability of the national social security system and approving social security reform has been a government priority. Therefore, there is an undisputed need for an actuarial study that calculates actuarially fair rates and compares the current scenario with the reform proposals. Multiple decrement actuarial models were used to calculate the fair rates considering a standard family (25-year-old worker, spouse, and two children), in which the man is three years older than the woman. The IBGE 2015 Extrapolated (mortality) and Álvaro Vindas (disability) tables were adopted as biometric assumptions, and a real wage growth rate of 2% p.a. and real interest rate of 3% p.a. were used.

ABSTRACT In this article, we have built a co-authorship network among researchers with CNPQ grant in research productivity (PQ) in the area of Industrial Engineering and analyze which Social Network Analysis metrics impact their productivity level. Unlike other studies that mostly analyze unweighted networks, ours explored more broadly the network since the metrics were calculated in three ways: unweighted, including the edges weights and including the edges and nodes’ attributes. Thus, the generated results are more precise and detailed since more information is obtained. We consider the h-index of the researchers as the nodes’ attributes and measured the impact using Kendall correlation. We show that geographical distance is still a barrier to collaboration among PQs in this area and that collaboration with researchers with different levels of grant has the greatest impact in the level of the grant a researcher has.

Resumo Neste artigo. Nós analisamos a rede de coautoria entre todos os bolsistas de produtividade do CNPq na área de probabilidade e estatística no Brasil. Nosso objetivo foi descrever e entender como medidas da rede influenciam na produtividade dos pesquisadores. A base de dados foi coletada do Plataforma Lattes do CNPq utilizando o programa scriptLattes, e uma ligação entre dois bolsistas representa o fato deles terem escrito um artigo juntos no período de 2009 à 2013. A rede é desconexa e tem apenas 4,7% das possíveis conexões. Por meio da análise de regressão, fomos capazes de inferir que as posições de centralidade de um autor importam para a produtividade dele ou dela. Como esperado, a centralidade de proximidade teve um efeito negativo na produtividade do bolsista, enquanto a centralidade de grau teve um efeito positivo.

Abstract In this paper, we analyzed the co-authorship network between all CNPq’s productivity research fellows in the Probability and Statistics area in Brazil. Our aim was to describe and to understand how network measures influence researchers’ productivity. The data was gathered from the CNPq’s Lattes Platform using the software scriptLattes, and a link between two fellows represents the fact that they wrote an article together from 2009 to 2013. The network is disconnected and has only 4.7% of its possible connections. Through a regression analysis, we were able to infer that the centrality positions of an author matters to his/her productivity. As expected, closeness centrality had a negative effect on fellows’ productivity, while the degree centrality had a positive effect.

ABSTRACT We discuss the rationality of burning money behavior from a new perspective: the mixed Nash equilibrium in 2 × 2 normal form games. We support our argument analyzing the first-order derivatives of the players' mixed equilibrium expected utility payoffs with respect to their own utility payoffs. We establish necessary and sufficient conditions that guarantee the existence of negative derivatives. In particular, games with negative derivatives are the ones that create incentives for burning money behavior since such behavior in these games improves the player's mixed equilibrium expected utility payoff. We show that a negative derivative of some player i 's mixed equilibrium expected utility payoff occurs if, and only if, he has a strict preference for one of the strategies of the other player. Moreover, negative derivatives always occur when they are taken with respect to player i 's highest and lowest game utility payoffs. We also present sufficient conditions that ensure that such derivatives are always non-negative in finite normal form games.

ABSTRACT Contributions from the sensitivity analysis of the parameters of the linear programming model for the elicitation of experts' beliefs are presented. The process allows for the calibration of the family of probability distributions obtained in the elicitation process. An experiment to obtain the probability distribution of a future event (Brazil vs. Spain soccer game in the 2013 FIFA Confederations Cup final game) was conducted. The proposed sensitivity analysis step may help to reduce the vagueness of the information given by the expert.

This paper analyzes defense systems taking into account the strategic interactions between two rational agents; one of them is interested in designing a defense system against purposeful attacks of the other. The interaction is characterized by a sequential game with perfect and complete information. Reliability plays a fundamental role in both defining agents' actions and in measuring performance of the defense system for which a series-parallel configuration is set up by the defender. The attacker, in turn, focuses on only one defense subsystem in order to maximize her efficiency in attacking. An algorithm involving backward induction is developed to determine the equilibrium paths of the game. Application examples are also provided.

In this article, we analyze how reasonable it is to play according to some Nash equilibria if players have a preference for one of their opponents' strategies. To formalize our argument, we propose the concepts of collaborative dominance and collaborative equilibrium studying some of its properties. First, we prove that if the collaborative equilibrium exists, then it is always efficient, what can be seen as a focal property. Moreover, we argue that one reason that may lead players not to collaborate is that they can focus on security instead of efficiency properties, in which case they would prefer to play according to maximin strategies. This argument allows us to reduce the hall of reasonable equilibria for games where a collaborative equilibrium exists. Finally, we show that two-player zero-sum games do not have collaborative equilibrium, and that if they contain a strategy profile composed only of collaboratively dominated actions, then such profile is a Nash equilibrium of the game.