Multi-PBil: an estimation distribution algorithm applied to multimodal optimization problems

The Estimation Distribution Algorithms (EDAs) compose an evolutionary metaheuristic whose main characteristic is the construction of solutions in randomly form, using a distribution of probabilities that evolves during the execution. The Population-Based Incremental Learning Algorithm (PBIL) is a type of EDA where the variables are independent, that is, they do not have significant interactions between themselves. The PBIL considers that the solutions can be represented as vectors of discrete variables, what makes it more adequate for combinatorial optimization problems. This paper presents a method called Multi-PBil that is an extension of PBIL with applications in multimodal problems. The Multi-PBil was developed with the goal to have an efficient and non expensive algorithm of search in multimodal spaces. From PBIL, it was implemented a routine that allows the Multi-PBil to create a probability model to act in the search space. A formula that allows initiating the probability models in regions of the search space next to the searched global points was applied in the process of the probability model initialization rule. The Multi-PBil method was tested and analyzed, presenting some experimental results that highlight its viability and characteristics. It is also shown a comparison of the performance between the Multi-PBil and a traditional Genetic Algorithm using the sharing method.VII Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Underinvoicing of exports, overinvoicing of imports, and the dollar premium on the black market

This paper is divided in two parts. The first is a theoretical development of the question of under or overinvoicing of exports and imports within the context of a model of choice between risky and secure assets. The second part attempts to ascertain the empirical evidence for the Brazilian economy. It is concluded that the hypothesis that the black market dollar premium plays a role in this process can not be rejected.

On the phase transitions of graph coloring and independent sets

We study combinatorial indicators related to the characteristic phase transitions associated with coloring a graph optimally and finding a maximum independent set. In particular, we investigate the role of the acyclic orientations of the graph in the hardness of finding the graph's chromatic number and independence number. We provide empirical evidence that, along a sequence of increasingly denser random graphs, the fraction of acyclic orientations that are `shortest' peaks when the chromatic number increases, and that such maxima tend to coincide with locally easiest instances of the problem. Similar evidence is provided concerning the `widest' acyclic orientations and the independence number

Os desafios da Organização Mundial do Comércio

The author appraises the current World Trade Organization identity crises. He evaluates the difficulties in concluding the Doha Round, the challenge of regional trade agreements and governance issues, particularly those related to new themes.Examina-se, no artigo, a atual crise de identidade da Organização Mundial do Comércio. Isso é feito pela análise de três desafios enfrentados atualmente pela organização. Primeiro, a dificuldade de conclusão da Rodada Doha. Segundo, a própria capacidade de negociação de acordos multilaterais diante da expansão do regionalismo. Por fim, está o problema de governança da organização, especialmente nos novos temas

Liberalização do comércio, integração regional e Mercado Comum do Sul: o papel do Brasil

RESUMO Este artigo adota uma abordagem evolutiva e sistêmica da questão da integração regional na América Latina, revisando os principais instrumentos de comércio preferencial na região, desde a experiência da LAIA (Associação de Integração Latino-Americana, Aladi) até o mercado comum do sul (Mercosul), e seu estágio intermediário, o programa de integração Argentina-Brasil. Especial atenção é dada à posição do Brasil, sendo o principal parceiro no comércio intrarregional dos países membros da Aladi e o país-chave para o sucesso do Mercosul, o experimento mais recente no processo de integração latino-americana. Os acordos comerciais preferenciais de Aladi foram profundamente afetados por suas crises econômicas dos anos 80, que atingiram praticamente todos os seus países membros, reduzindo assim os fluxos comerciais intrarregionais e as virtudes de criação de comércio de seu principal mecanismo multilateral, o Preferência Tarifária Regional (PTR). Em meados da década de 80, o Brasil e a Argentina já haviam decidido iniciar um novo processo de integração bilateral, que expandiu e abarcou os acordos setoriais assinados sob a estrutura Aladi. Após concordar com os procedimentos institucionais do processo de integração bilateral, os dois países negociaram e concluíram um Acordo de Complementação Econômica (ACE), que se tornou a base do Tratado de Assunção, assinado em março de 1991 com a adesão do Paraguai e Uruguai. O novo experimento de integração sub-regional ocorre no meio dos processos de liberalização do comércio e do desmantelamento das políticas de substituição de importações nos quatro países

Multi-PBil: an estimation distribution algorithm applied to multimodal optimization problems

The Estimation Distribution Algorithms (EDAs) compose an evolutionary metaheuristic whose main characteristic is the construction of solutions in randomly form, using a distribution of probabilities that evolves during the execution. The Population-Based Incremental Learning Algorithm (PBIL) is a type of EDA where the variables are independent, that is, they do not have significant interactions between themselves. The PBIL considers that the solutions can be represented as vectors of discrete variables, what makes it more adequate for combinatorial optimization problems. This paper presents a method called Multi-PBil that is an extension of PBIL with applications in multimodal problems. The Multi-PBil was developed with the goal to have an efficient and non expensive algorithm of search in multimodal spaces. From PBIL, it was implemented a routine that allows the Multi-PBil to create a probability model to act in the search space. A formula that allows initiating the probability models in regions of the search space next to the searched global points was applied in the process of the probability model initialization rule. The Multi-PBil method was tested and analyzed, presenting some experimental results that highlight its viability and characteristics. It is also shown a comparison of the performance between the Multi-PBil and a traditional Genetic Algorithm using the sharing method.VII Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Reflexões sobre a administração municipal da educação: um início de conversa...

Este artigo discute uma experiência de administração pública na educação na cidade de São Carlos, procurando realizar uma reflexão sobre os entraves e as dificuldades encontrados, podendo servir como uma contribuição, na medida em que recupera algumas propostas, ações e os devidos cuidados com alguns percalços à frente de órgão público da educação municipal. Após apresentar o detalhamento do município e dos dados educacionais, o texto aborda as questões da organização da educação municipal e dos problemas relativos ao controle social na educação. Por fim, aborda, de maneira mais pormenorizada, processos, proposições e dinâmicas realizados no primeiro semestre de 2001, período analisado neste artigo. Reflections on municipal administration of education: start of conversation Abstract This article discusses an experience of Public Administration of Education in the city of São Carlos. This research tries to analyze impediments and difficulties of municipal administration of public education; it also can be considered a contribution, in the way that it recovers proposals, actions and the necessary cautions related to difficulties that public organisms of municipal education have. Right after the municipality and its education data introduction, this text approaches to questions related to the organization of municipal education and problems related to social control of education. Finally, it analyzes, in a more detailed way, processes, propositions, dynamics and difficulties identified in the first semester of 2001, the term focused in this article