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Jorge Rivera Florentino Chavira Alexander Loukianov Susana Ortega Juan J. Raygoza 《Journal of The Franklin Institute》2014
This work deals with the discrete-time modeling of a boost DC-to-DC power converter by means of a discrete Lagrangian formulation based on the midpoint rule integration method. Then in the basis of this model, a discrete-time sliding mode regulator is designed in order to force the boost circuit to track a DC-biased sinusoidal signal. Simulations and experimental tests are carried on where the great performance of the proposed methodology is verified. 相似文献
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David Ruano-Ordás Florentino Fdez-Riverola José R. Méndez 《Information processing & management》2018,54(2):303-317
One of the most relevant problems affecting the efficient use of e-mail to communicate worldwide is the spam phenomenon. Spamming involves flooding Internet with undesired messages aimed to promote illegal or low value products and services. Beyond the existence of different well-known machine learning techniques, collaborative schemes and other complementary approaches, some popular anti-spam frameworks such as SpamAssassin or Wirebrush4SPAM enabled the possibility of using regular expressions to effectively improve filter performance. In this work, we provide a review of existing proposals to automatically generate fully functional regular expressions from any input dataset combining spam and ham messages. Due to configuration difficulties and the low performance achieved by analysed schemes, in this work we introduce DiscoverRegex, a novel automatic spam pattern-finding tool. Patterns generated DiscoverRegex outperform those created by existing approaches (able to avoid FP errors) whilst minimising the computational resources required for its proper operation. DiscoverRegex source code is publicly available at https://github.com/sing-group/DiscoverRegex. 相似文献
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Rodrigo Drumond Vieira José Roberto da Rocha Bernardo Maria Evagorou Viviane Florentino de Melo 《International Journal of Science Education》2013,35(7):1113-1139
In this article, we focus on the contributions that a simulated jury-based activity might have for pre-service teachers, especially for their active participation and learning in teacher education. We observed a teacher educator using a series of simulated juries as teaching resources to help pre-service teachers develop their pedagogical knowledge and their argumentation abilities in a physics teacher methods course. For the purposes of this article, we have selected one simulated jury-based activity, comprising two opposed groups of pre-service teachers that presented aspects that hinder the teachers' development of professional knowledge (against group) and aspects that allow this development (favor group). After the groups’ presentations, a group of judges was formed to evaluate the discussion. We applied a multi-level method for discourse analysis and the results showed that (1) the simulated jury afforded the pre-service teachers to position themselves as active knowledge producers; (2) the teacher acted as ‘animator' of the pre-service teachers' actions, showing responsiveness to the emergence of circumstantial teaching and learning opportunities and (3) the simulated jury culminated in the judges’ identification of the pattern ‘concrete/obstacles–ideological/possibilities' in the groups’ responses, which was elaborated by the teacher for the whole class. Implications from this study include using simulated juries for teaching and learning and for the development of the pre-service teachers’ argumentative abilities. The potential of simulated juries to improve teaching and learning needs to be further explored in order to inform the uses and reflections of this resource in science education. 相似文献
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The present study explored the effects of three different activity conditions on three attentional functions: alerting, orienting, and executive control. A group of highly experienced cyclists performed the Attention Network Test-Interactions (Callejas, Lupiá?ez, & Tudela, 2004) at rest, during moderate aerobic exercise, and during intense aerobic exercise. Results indicated that aerobic exercise accelerated reaction time and reduced the alerting effect compared with the rest condition. However, aerobic exercise did not modulate the functioning of either the orienting or the executive control attentional networks. No differences in reaction time or attentional functioning were observed between the two aerobic exercise workloads. The present results suggest that moderate aerobic exercise modulates the functioning of phasic alertness by increasing the general state of tonic vigilance. 相似文献
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