Enhancing arithmetic in pre-schoolers with comparison or number line estimation training: Does it matter?

Children's intuitive understanding of number, i.e. number sense, is associated with individual differences in mathematics achievement. To investigate the causal association between number sense, traditionally assessed with comparison or number line estimation tasks, and mathematics achievement, often assessed with an arithmetic test, an intervention study was conducted that aimed at training either comparison or number line estimation skills. We contrasted a comparison and number line estimation training. By doing so, we wanted to address the question which intervention had the largest effect on arithmetic. In addition, such a direct comparison between comparison and number line estimation trainings would allow us to get more insight in the association between both tasks. Participants were 151 five-year-olds that were randomly allocated to either an experimental condition (i.e. comparison or number line estimation) or one of the two control conditions (i.e., active control condition and empty control condition) in a pretest-posttest design measuring number knowledge, (non-)symbolic comparison and number line estimation and arithmetic. The results showed that both comparison and number line estimation trainings had a positive effect on arithmetic. However, the absence of transfer effects from one task to another, also suggested that comparison and number line estimation rely on different mechanisms and probably influence arithmetic through different mechanisms.     

一道IMO试题的推广及应用

给出了一道第36届IMO不等式赛题的推广,并应用推广结论解证了一组不等式。     

Solving arithmetic problems in first and second language: Does the language context matter?

Learning mathematics in a second language is a challenge for many learners. The purpose of the study was to provide new insights into the role of the language context in mathematic learning and more particularly arithmetic problem solving. We investigated this question in a German–French bilingual educational setting in Luxembourg. Participants with increasing bilingual proficiency levels were invited to solve additions in both their first and second instruction languages: German and French. Arithmetic problems were presented in two different conditions: preceded by a semantic judgment or without additional language context. In the French session we observed that additions were systematically performed faster in the condition with an additional language context. In contrast no effect of the context was observed in the German session. In conclusion, providing a language context enhanced arithmetic performances in bilinguals' second instruction language. This finding entails implications for designing optimal mathematic learning environments in multilingual educational settings.     

基于路段流量的交通分配模型的遗传算法

本文讨论了基于路段流量的交通分配问题,指出其最优解是满足wardrop平衡条件的。对这类问题本文采用了遗传算法,并给出了算法的基本思想及详细的实现过程。数值实验表明该方法是可行有效的,可以用于实际交通路网的配流计算。     

应用遗传算法解决数据挖掘问题的实例分析

本文应用遗传算法构造了数据挖掘中关联规则的基本模型，借助此模型可以有效的计算出关联规则中的置信度和支持度。在此基础上以一汽大众汽车有限公司员工的培训信息为基础，通过比较置信度和支持度，进一步分析了员工是否适合现任的职位以及员工内在的潜质等问题，从而使员工素质评价体系更为科学。     

动物转基因技术的研究及应用前景

介绍了基因转移技术在动物生产上的应用,说明基因工程技术已成为动物育种方法发展的方向。通过动物转基因技术的研究,必将在生产实践中产生深远的影响。     

用遗传算法的思想求解大规模线性方程组

本文研究了用遗传算法的思想求解大规模线性方程组的方法,并在计算机上作了试验,得到了较好的结果     

中国红豆杉属及其近缘植物的遗传变异和亲缘关系分析

采用水平式淀粉凝胶电泳技术,对中国产红豆杉属Taxus 3种1变种以及白豆杉Pseudotaxus chienii共12个居群的遗传多样性进行了检测。对7个酶系统9个酶位点的分析结果表明,红豆杉属和 白豆杉的种内遗传多样性水平较高,各类群的多态位点比率(P)为44.4％～77.8％,等位基因平均数 (A)为1．6～2．1,平均期望杂合度(He)和实际观察杂合度(Ho)分别为0.065～0.152和0.068～0.111。 根据对等位酶实验结果的分析,结果表明除云南红豆杉T．yunnanensis与红豆杉属其它几个种的遗传 一致度稍低(I=0.727～0.804)外,红豆杉属的其它几个种的遗传一致度较高(0.906～0.995),体现其 亲缘关系很近。笔者建议将红豆杉属的这几个种合并为一个种,并根据地理分布及不同生境发生的变 异在种下设地理宗。同时根据等位酶的实验分析结果,白豆杉和红豆杉属各种的比较有显著差异,支持白豆杉作为单独属Pseudotaxus的处理。     

基于模式识别的创新概念设计

现提出了一种基于遗传算法的自动求解算法,并将该算法在CAD中的应用作了展望。该算法采用基元模式识别方法识别原有的以图像形式存储的模型,在适应度函数中引入形象度和抽象度的标准,并辅以人机交互的方式来判别算法运行过程中产生的个体。实验结果表明,该算法可以充分利用原有设计图案,并能够在运行过程中产生大量的优良个体。     

中国动植物遗传资源利用现状和制度完善

我国的动植物遗传资源丰富而富有价值。近年来,我国遗传资源流失和国外恶意剽窃等问题频频发生,对资源的过度开发和不合理利用问题也十分突出。主要原因有两方面,客观上我国经济快速发展和庞大的人口基数导致对资源的需求量急剧上升;主观上认为资源极大丰富,是可再生资源的传统观点并未得到根本改变,无论是管理者、经营者还是消费者都缺乏对资源稀缺性和珍贵性的正确认识,导致对资源的不合理使用。虽然我国已初步制订了相应的政策法规,并利用数据库等科技手段加强对遗传资源的保护和利用工作,但是在动植物遗传资源利用及保护方面的法规、政策和制度上仍存在诸多不足。法律层面上,存在立法体系不完整,缺乏操作性等问题;制度层面上,存在管理机构不明,指导体制缺位等缺陷。相关部门应在立法、制度建设、知识产权研究、培育市场化机制等方面入手,完善我国动植物遗传资源保护和利用制度。