A Markov random field model for combining optimum-path forest classifiers using decision graphs and game strategy approach

The research on multiple classifiers systems includes the creation of an ensemble of classifiers and the proper combination of the decisions. In order to combine the decisions given by classifiers, methods related to fixed rules and decision templates are often used. Therefore, the influence and relationship between classifier decisions are often not considered in the combination schemes. In this paper we propose a framework to combine classifiers using a decision graph under a random field model and a game strategy approach to obtain the final decision. The results of combining Optimum-Path Forest (OPF) classifiers using the proposed model are reported, obtaining good performance in experiments using simulated and real data sets. The results encourage the combination of OPF ensembles and the framework to design multiple classifier systems. © 2011 Springer-Verlag.

Combinação linear ponderada na definição de áreas prioritárias à conectividade entre fragmentos florestais em ambiente SIG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Improving accuracy and speed of optimum-path forest classifier using combination of disjoint training subsets

The Optimum-Path Forest (OPF) classifier is a recent and promising method for pattern recognition, with a fast training algorithm and good accuracy results. Therefore, the investigation of a combining method for this kind of classifier can be important for many applications. In this paper we report a fast method to combine OPF-based classifiers trained with disjoint training subsets. Given a fixed number of subsets, the algorithm chooses random samples, without replacement, from the original training set. Each subset accuracy is improved by a learning procedure. The final decision is given by majority vote. Experiments with simulated and real data sets showed that the proposed combining method is more efficient and effective than naive approach provided some conditions. It was also showed that OPF training step runs faster for a series of small subsets than for the whole training set. The combining scheme was also designed to support parallel or distributed processing, speeding up the procedure even more. © 2011 Springer-Verlag.

O investimento em transmissão de energia elétrica no Brasil: uma análise da atratividade das concessões por leilão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação das alterações dentárias e esqueléticas induzidas pelo uso do aparelho de Herbst no tratamento da classe II na dentadura mista: Revisão sistemática

Objective: evaluate the immediate dental and skeletal changes induced by the Herbst appliance on early treatment of Angle´s Class II malocclusion. Material and Method: several electronic databases such as Scopus, Pub Med, Medline, Cochrane Library, Lilacs and Scielo were searched. The abstracts that fullfilled the selection criteria were selected and those that did not provide enough information about these criteria were selected but the final decision of including them or not on the research, was taken after the complete reading of the article. The selection criteria were: clinical studies with Class II individuals, both male and female, with initial age of 7 to 10 years, treated with the Herbst appliance that analysed the dental and/or skeletal changes evaluated on lateral cephalometric radiographs; researches where the treatment performed did not involve extractions or surgical interventions; studies that included patients without syndromes or health concerns and articles published in English or Portuguese. Results and Conclusions: five articles were selected. The articles showed that significant changes happened in the mandibular sagittal lenght, on facial convexity angle, on maxillo-mandibular relationship, on retroclination of the upper incisors and on distal movement of the upper molars, on proclination of the lower incisors and on extrusion of the lower molars. The appliance exerted a limited effect on the anterior relocation of the maxillary complex and on facial heights. However, more studies about the performance of the Herbst appliance on early treatment of Class II are needed.

Teoria e metodologia na escrita da História do Brasil: Afonso de Taunay e a Academia Brasileira de Letras

The history of historiography in recent decades has the breathing space needed in the concerns of historians and has been transformed into a research field with its own issues. Uploaded this in perspective, this paper aims to understand how aspects of the theory of history and methodology have been addressed by Afonso de Escragnolle Taunay (1876-1958). We selected the letters exchanged by the author, the speeches of acceptance at the ABL, some articles and books produced by Taunay in the 1930s. In the first decades of the twentieth century, when it sought to define the historiography and its limits in both the literature and social science sources, the subjectivity is presented as the final decision making of the author, especially those related to the new site production Taunay, the Brazilian Academy of Letters.