Résumé
ABSTRACT: The aim of this study was to evaluate the growth responses of various Eucalyptus and Corymbia species subjected to different intensities of simulated hypergravity relative to the control. A centrifuge was used to simulate hypergravity. It was developed and built at the Centro de Microgravidade of the Pontifícia Universidade Católica do Rio Grande do Sul, Brazil. Seeds of five Eucalyptus and one Corymbia species (E. grandis, Eucalyptus globulus, Eucalyptus benthamii, Eucalyptus saligna, Eucalyptus dunnii, and C. maculata) were placed on moist germination paper in plastic containers and rotated at speeds simulating 5 Gz and 7 Gz for different lengths of time. Hypergravity technology significantly increased seedling production (diameter, height, and survival at 120 days) in nurseries. In E. globulus, the effects of hypergravity were significant at 7 Gz at all lengths of time (from 1 d to 9 days). Effects of hypergravity were significant in both E. benthamii and E. grandis at 7 Gz and 8 h exposure. Therefore, simulated hypergravity could be used in performance tests of Eucalyptus seedlings in early stages of development.
RESUMO: O presente trabalho objetivou avaliar o crescimento de espécies de Eucalyptus e Corymbia em diferentes intensidades de hipergravidade simulada em relação ao controle. Uma centrífuga foi usada para simular a hipergravidade. Este equipamento foi desenvolvido e construído no Centro de Microgravidade da Pontifícia Universidade Católica do Rio Grande do Sul, Brasil. Sementes de cinco espécies de Eucalyptus e uma de Corymbia (E. grandis, E. globulus, E. benthamii, E. saligna, E. dunnii, e C. maculata) foram colocadas em papeis de germinação e em recipientes plásticos, em que foram rotacionadas a velocidades simuladas de 5 Gz e 7 Gz, por diferentes períodos de tempo. A tecnologia da hipergravidade proporcionou aumento significativo na taxa de crescimento das plântulas (diâmetro, altura e sobrevivência aos 120 dias) no viveiro. Para Eucalyptus globulus, os efeitos da hipergravidade foram significativos na intensidade de 7 Gz em qualquer período de tempo (do primeiro até o nono dia). Os efeitos da hipergravidade foram significativos para as espécies E. benthamii e E. grandis na intensidade 7 Gz e 8 horas de exposição. Dessa maneira, a hipergravidade simulada apresenta potencial de uso em testes com plântulas de eucaliptos em estágios iniciais de desenvolvimento.
Résumé
Abstract Introduction Skateboarding is one of the most popular cultures in Brazil, with more than 8.5 million skateboarders. Nowadays, the discipline of street skating has gained recognition among other more classical sports and awaits its debut at the Tokyo 2020 Summer Olympic Games. This study aimed to explore the state-of-the-art for inertial measurement unit (IMU) use in skateboarding trick detection, and to develop new classification methods using supervised machine learning and artificial neural networks (ANN). Methods State-of-the-art knowledge regarding motion detection in skateboarding was used to generate 543 artificial acceleration signals through signal modeling, corresponding to 181 flat ground tricks divided into five classes (NOLLIE, NSHOV, FLIP, SHOV, OLLIE). The classifier consisted of a multilayer feed-forward neural network created with three layers and a supervised learning algorithm (backpropagation). Results The use of ANNs trained specifically for each measured axis of acceleration resulted in error percentages inferior to 0.05%, with a computational efficiency that makes real-time application possible. Conclusion Machine learning can be a useful technique for classifying skateboarding flat ground tricks, assuming that the classifiers are properly constructed and trained, and the acceleration signals are preprocessed correctly.