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851.
Monika Dockendorff Horacio Solar 《International Journal of Mathematical Education in Science & Technology》2018,49(1):66-84
This case study investigates the impact of the integration of information and communications technology (ICT) in mathematics visualization skills and initial teacher education programmes. It reports on the influence GeoGebra dynamic software use has on promoting mathematical learning at secondary school and on its impact on teachers’ conceptions about teaching and learning mathematics. This paper describes how GeoGebra-based dynamic applets – designed and used in an exploratory manner – promote mathematical processes such as conjectures. It also refers to the changes prospective teachers experience regarding the relevance visual dynamic representations acquire in teaching mathematics. This study observes a shift in school routines when incorporating technology into the mathematics classroom. Visualization appears as a basic competence associated to key mathematical processes. Implications of an early integration of ICT in mathematics initial teacher training and its impact on developing technological pedagogical content knowledge (TPCK) are drawn. 相似文献
852.
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854.
Mathematical definitions are an important mathematical construct which has been noted as a challenging topic for both teachers and students. This study provides an analysis of the form and content of a set of 308 definitions of quadrilateral types provided by 44 novice pre-service elementary teachers (NPSTs) who had not yet studied geometry or definitions on the college level. Analysis of definition structure including necessary, sufficient, and minimal conditions, as well as hierarchical and partitional structure, provides insight into what NPSTs may think about the form of mathematical definitions in general. Analysis of the properties used in definitions of each shape type and the frequency of those properties reveals the shape types with which NPSTs are most and least familiar. These results are presented alongside possible applications and implications for instruction. 相似文献
855.
为了进一步提高基于P2P的内容分发网CDN(content delivery network)的搜索效率,对用户就近组成的节点群(peer group)进行了研究,提出了节点群相似的概念和基于关键词的节点群相似性度量模型.当一个需求在本节点群不能满足时,优先到相似性高的节点群中查找,以较快地满足跨节点群的需求.度量模型对任意两个节点群首先根据节点中各文档关键词的一致程度判断对应两个节点的相似度,然后根据相似节点对的数量和相似度来判断两个节点群相似度.实验表明,使用所提出的度量模型得出的计算结果比传统的基于VSM的算法更接近于实际情况. 相似文献
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857.
Manuel Flores 《Mathematische Zeitschrift》2008,260(3):699-712
In this paper we show that Kohn’s solution to the \({\bar\partial_b}\) problem fails to be hypoelliptic on some class of high codimension submanifolds of \({\mathbb{C}^n}\). The examples presented here carry a Lie group structure which generalize the one-dimensional Heisenberg group. 相似文献
858.
In this paper, we propose a modification of Benson’s algorithm for solving multiobjective linear programmes in objective space
in order to approximate the true nondominated set. We first summarize Benson’s original algorithm and propose some small changes
to improve computational performance. We then introduce our approximation version of the algorithm, which computes an inner
and an outer approximation of the nondominated set. We prove that the inner approximation provides a set of -nondominated points. This work is motivated by an application, the beam intensity optimization problem of radiotherapy treatment
planning. This problem can be formulated as a multiobjective linear programme with three objectives. The constraint matrix
of the problem relies on the calculation of dose deposited in tissue. Since this calculation is always imprecise solving the
MOLP exactly is not necessary in practice. With our algorithm we solve the problem approximately within a specified accuracy
in objective space. We present results on four clinical cancer cases that clearly illustrate the advantages of our method. 相似文献
859.
Andrew Bakan 《Journal of Mathematical Analysis and Applications》2008,339(1):197-216
For the sets , 1?p<∞, of positive finite Borel measures μ on the real axis with the set of algebraic polynomials P dense in Lp(R,dμ), we establish a majorization principle of their “boundaries,” i.e. for every there exists such that dμ/dν?1. A corresponding principle holds for the sets , p>0, of non-negative upper semi-continuous on R functions (weights) w such that P is dense in the space : For every there exists such that w?ω. 相似文献
860.
J. Ch. Pomerol 《Mathematical Programming》1980,19(1):352-355
We give a new minisup theorem for noncompact strategy sets. Our result is of the type of the Matthies-Strang-Christiansen minimax theorem where the hyperplane should be replaced by any closed convex set. As an application, we derive a slight generalization of the Matthies-Strang-Christiansen minimax theorem. 相似文献