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Xu-Guang Li Jun-Xiu Chen Silviu-Iulian Niculescu Arben Çela 《Journal of The Franklin Institute》2018,355(17):8683-8697
Most of the reported Lotka–Volterra examples have at most one stability interval for the delay parameters. Furthermore, the existing methods fall short in treating more general case studies. Inspired by some recent results for analyzing the stability of time-delay systems, this paper focuses on a deeper characterization of the stability of Lotka–Volterra systems w.r.t. the delay parameters. More precisely, we will introduce the recently-proposed frequency-sweeping approach to study the complete stability problem for a broad class of linearized Lotka–Volterra systems. As a result, the whole stability delay-set can be analytically determined. Moreover, as a significant byproduct of the proposed approach, some Lotka–Volterra examples are found to have multiple stability delay-intervals. To the best of the authors’ knowledge, such a characterization represents a novelty for having some insights in the population dynamics: in some situations, a longer maturation period of species is helpful for the stability of a population system. 相似文献
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Dirk T. Tempelaar Alexandra Niculescu Bart Rienties Wim H. Gijselaers Bas Giesbers 《The Internet and Higher Education》2012,15(3):161-169
This empirical study investigates students' learning choices for mathematics and statistics in a blended learning environment, composed of both online and face-to-face learning components. The students (N = 730) were university freshmen with a strong diversity in prior schooling and a wide range of proficiency in quantitative subjects. In this context, we investigated the impact that individual differences in achievement emotions (enjoyment, anxiety, boredom, hopelessness) had on students' learning choices, in terms of the intensity of using the online learning mode versus the face-to-face mode. Unlike the general level of learning activities, which is only minimally influenced by achievement emotions, these emotions appear to have a moderately strong effect on a student's preference for online learning. Following this, we explored the antecedents of achievement emotions. Through the use of path-modeling, we conclude that while goal setting behavior only marginally impacts achievement emotions, effort views—a crucial component of the social-cognitive model of implicit theories of intelligence—have a substantial impact on achievement emotions. 相似文献
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