A systematic comparison of supervised classifiers

Pattern recognition techniques have been employed in a myriad of industrial, medical, commercial and academic applications. To tackle such a diversity of data, many techniques have been devised. However, despite the long tradition of pattern recognition research, there is no technique that yields the best classification in all scenarios. Therefore, the consideration of as many as possible techniques presents itself as an fundamental practice in applications aiming at high accuracy. Typical works comparing methods either emphasize the performance of a given algorithm in validation tests or systematically compare various algorithms, assuming that the practical use of these methods is done by experts. In many occasions, however, researchers have to deal with their practical classification tasks without an in-depth knowledge about the underlying mechanisms behind parameters. Actually, the adequate choice of classifiers and parameters alike in such practical circumstances constitutes a long-standing problem and is the subject of the current paper. We carried out a study on the performance of nine well-known classifiers implemented by the Weka framework and compared the dependence of the accuracy with their configuration parameter configurations. The analysis of performance with default parameters revealed that the k-nearest neighbors method exceeds by a large margin the other methods when high dimensional datasets are considered. When other configuration of parameters were allowed, we found that it is possible to improve the quality of SVM in more than 20% even if parameters are set randomly. Taken together, the investigation conducted in this paper suggests that, apart from the SVM implementation, Weka's default configuration of parameters provides an performance close the one achieved with the optimal configuration

Análise do perfil socioeconômico dos pescadores profissionais artesanais dos municípios de Aquidauana e Anastácio/MS.

O propósito deste trabalho é analisar o perfil socioeconômico dos pescadores artesanais dos municípios de Aquidauana e Anastácio / MS. Além dos coeficientes econômicos, levou-se em consideração a fala do pescador com respeito a temas relacionados ao seu contexto. Foram considerados 145 pescadores moradores destes municípios cadastrados no Instituto do Meio Ambiente do Mato Grosso do Sul ? IMASUL, assumindo esse numero como representativo do total da comunidade de pescadores artesanais. Observou-se a tendência de que o pescador típico tenha em média 49,51 anos de idade, e não mais que a quarta serie do ensino fundamental. São na sua maioria homens, casados, na faixa entre 40 e 50 anos, sendo que mais da metade tem até dois filhos. Esse pescador é nascido na própria localidade, 43,05%, sendo ainda 75,69% nascidos no estado do Mato Grosso do Sul. Quanto à renda mensal, 66,5% ganham até um salário mínimo. Quanto à permanência dos filhos na profissão, apresentaram argumentos relacionados com as dificuldades da profissão e a falta de perspectiva de futuro, tanto no sentido econômico como ecológico. A maior queixa dos pescadores relaciona-se com a falta de acesso ao rio, a presença de turistas e as proibições de usos de petrechos como o anzol de galho. Notou-se na fala dos pescadores a grande oposição ao trabalho na cidade, onde a falta de estudo impossibilita a obtenção de rendimentos como os provenientes da pesca

Good practices for a literature survey are not followed by authors while preparing scientific manuscripts

The number of citations received by authors in scientific journals has become a major parameter to assess individual researchers and the journals themselves through the impact factor. A fair assessment therefore requires that the criteria for selecting references in a given manuscript should be unbiased with respect to the authors or the journals cited. In this paper, we advocate that authors should follow two mandatory principles to select papers (later reflected in the list of references) while studying the literature for a given research: i) consider similarity of content with the topics investigated, lest very related work should be reproduced or ignored; ii) perform a systematic search over the network of citations including seminal or very related papers. We use formalisms of complex networks for two datasets of papers from the arXiv repository to show that neither of these two criteria is fulfilled in practice

Predicting language diversity with complex network

Evolution and propagation of the world's languages is a complex phenomenon, driven, to a large extent, by social interactions. Multilingual society can be seen as a system of interacting agents, where the interaction leads to a modification of the language spoken by the individuals. Two people can reach the state of full linguistic compatibility due to the positive interactions, like transfer of loanwords. But, on the other hand, if they speak entirely different languages, they will separate from each other. These simple observations make the network science the most suitable framework to describe and analyze dynamics of language change. Although many mechanisms have been explained, we lack a qualitative description of the scaling behavior for different sizes of a population. Here we address the issue of the language diversity in societies of different sizes, and we show that local interactions are crucial to capture characteristics of the empirical data. We propose a model of social interactions, extending the idea from, that explains the growth of the language diversity with the size of a population of country or society. We argue that high clustering and network disintegration are the most important characteristics of models properly describing empirical data. Furthermore, we cancel the contradiction between previous models and the Solomon Islands case. Our results demonstrate the importance of the topology of the network, and the rewiring mechanism in the process of language change

Soil enzyme activity in conservation systems in the Southwestern Brazilian Amazon.

Conservation agriculture in family production in the sandy soil of Mâncio Lima municipality, western Acre State, has a positive effect on its biological attributes.Editores: Rafael Silvaro; Marie Luise Carolina Bartz

Novo modelo de negócios para desenvolvimento de biodefensivos pela Embrapa: projeto piloto Plataforma de Serviços Customizados Embrapa Recursos Genéticos e Biotecnologia.

O objetivo geral dessa proposta é buscar solução alternativa para otimizar as oportunidades para a Embrapa em relação ao desenvolvimento de soluções de inovação para o mercado B2B de Biodefensivos, por meio de novo modelo de negócio de inovação, baseado na criação de uma plataforma de serviços técnicos especializados relacionados às diferentes etapas do desenvolvimento da solução tecnológica, customizados de acordo com o interesse e perfil do cliente, a partir de projeto piloto a ser desenvolvido na Embrapa Recursos Genéticos e Biotecnologia.Monografia (Especialização) - Programa Corporativo de MBA em Gestão da Inovação e Capacidade Tecnológica, Fundação Getúlio Vargas, Brasília, DF