53 resultados para Navy Center for Applied Research in Artificial Intelligence (U.S.)


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In this paper, a trajectory tracking control problem for a nonholonomic mobile robot by the integration of a kinematic neural controller (KNC) and a torque neural controller (TNC) is proposed, where both the kinematic and dynamic models contains disturbances. The KNC is a variable structure controller (VSC) based on the sliding mode control theory (SMC), and applied to compensate the kinematic disturbances. The TNC is a inertia-based controller constituted of a dynamic neural controller (DNC) and a robust neural compensator (RNC), and applied to compensate the mobile robot dynamics, and bounded unknown disturbances. Stability analysis with basis on Lyapunov method and simulations results are provided to show the effectiveness of the proposed approach. © 2012 Springer-Verlag.

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Many topics related to association mining have received attention in the research community, especially the ones focused on the discovery of interesting knowledge. A promising approach, related to this topic, is the application of clustering in the pre-processing step to aid the user to find the relevant associative patterns of the domain. In this paper, we propose nine metrics to support the evaluation of this kind of approach. The metrics are important since they provide criteria to: (a) analyze the methodologies, (b) identify their positive and negative aspects, (c) carry out comparisons among them and, therefore, (d) help the users to select the most suitable solution for their problems. Some experiments were done in order to present how the metrics can be used and their usefulness. © 2013 Springer-Verlag GmbH.

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Feature selection aims to find the most important information from a given set of features. As this task can be seen as an optimization problem, the combinatorial growth of the possible solutions may be inviable for a exhaustive search. In this paper we propose a new nature-inspired feature selection technique based on the Charged System Search (CSS), which has never been applied to this context so far. The wrapper approach combines the power of exploration of CSS together with the speed of the Optimum-Path Forest classifier to find the set of features that maximizes the accuracy in a validating set. Experiments conducted in four public datasets have demonstrated the validity of the proposed approach can outperform some well-known swarm-based techniques. © 2013 Springer-Verlag.

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This study aims to investigate alcohol consumption within social groups for the elderly in So Jos, dos Campos-Brazil, and to check for a correlation between alcohol consumption and quality of life. A sample of 500 individuals participating on social groups for the elderly were interviewed by using the Alcohol Use Disorders Identification Test (AUDIT) to verify alcohol consumption; the Medical Outcomes Study 36 Item Short Form (SF-36), for evaluating quality of life; and the Oral Health Impact Profile short form (OHIP-14), for evaluating oral health-related quality of life. The average alcohol consumption was very low (1.48), being higher in men (2.23) than women (1.09). The SF-36 average score for the domain of physical function was 70.5; for role-physical function 64.9; for bodily pain,68.3; for general health 73.8; for vitality,72.4; for social function 82.8; for role-emotional function 72.3 and for mental health 75.0. The OHIP-14 average score was 3.87. AUDIT did not correlate with SF-36 domains, or with OHIP-14. However, there was a negative correlation between OHIP 14 and all SF-36 domains. This elderly sample has a very low consumption of alcohol, and no correlation was found between alcohol consumption and oral and medical quality of life.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The establishment of laboratory colonies of ticks is often hampered by their lack of adaptation to alternative hosts. The aim of this study was to artificially feed partially engorged Dermacentor (Anocentor) nitens females through plastic tips, and to identify what are the optimal conditions of application of this technique to get as much as possible close to the natural conditions. The technique of artificial feeding through plastic tips allowed the engorgement of D. nitens ticks to a final weight within the normal range for the species. (C) 2014 Published by Elsevier GmbH.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)