三元函数极值的探索

函数极值的存在性及判别方法是微分的重要应用之一.文章就三元函数给出了判别极值的存在的一个必要条件和充分条件.     

Everything is illuminated: What big data can tell us about teacher commentary

What happens to writing instructors’ feedback when they use a common rubric and an online tool to respond to student papers in a first-year composition course at a large state university in the United States? To investigate this question, we analyze the 118,611 comments instructors made when responding to 17,433 student essays. Using concordance software to quantify teachers’ use of rubric terms, we found instructors were primarily concerned with global, substantive, higher-order concerns—such as responding to students’ rhetorical situations, use of reason, and organization—rather than lower-order concerns about grammar or formatting. Given past research has determined teachers overemphasize lower-order concerns such as grammar, mechanics, and punctuation (Connors and Lunsford, 1988, Lunsford and Lunsford, 2008, Moxley and Joseph, 1989, Moxley and Joseph, 1992, Schwartz, 1984, Sommers, 1982, Stern and Solomon, 2006), these results may suggest the possibility of a generational shift when it comes to response to student writing. Aggregating teacher commentary, student work, and peer review responses via digital tools and employing concordance software to identify big-data patterns illuminates a new assessment practice for Writing Program Administrators—the practice of Deep Assessment.     

电影特刊与早期中国电影研究

20世纪20年代,借助着民族电影业蓬勃崛起之势,更得益于电影这一媒介的社会影响力日益扩大,国人自办的电影刊物获得了迅速发展.20年代最具代表性的电影刊物便是“电影特刊”.本文探寻电影特刊的特性及其演变轨迹,同时对学术研究中如何开掘与使用电影特刊的相关问题加以探讨,以期为早期中国电影史的研究拓展新的路径.     

论大数据时代政府职能转变中的商会发展——以湖南民营经济为例

商会组织的发育程度是衡量一个国家或地区市场主体成熟度的重要标志,大数据时代背景下,加强对政府职能转变与商会发展的研究,具有重要的理论意义与重大的实践价值。文章分析了大数据时代政府职能转变对经济社会发展的巨大影响与作用,探讨了民营企业面临的挑战和商会发展面临的新机遇,提出了湖南商会服务民营经济存在的问题和对策。     

Multiple regression analysis of sib-pair data on reading to detect quantitative trait loci

A simple extension of the DeFries and Fulker multiple regression model for twin analysis is applied to the problem of detecting linkage in a quantitative trait. The method, employing sib pairs, is based on that of Haseman and Elston. Reading data from 19 extended pedigrees were analyzed employing RLFPs as markers on chromosome 15 and using the widely available statistical applications software package, SAS. A number of possible linkages were detected, indicating that this approach is both powerful and effective, especially in the case of selected samples. Detecting genotype-environment interaction and the issue of power are briefly discussed. The programs used are available upon request.     

基于分形方法估算部分商为a或b的连分数集维数

连分数的展开式具有结构上的自相似性,部分商满足一定条件的连分数构成的集合是分形集,通过构造迭代映射的方法估算其Hausdorff维数.     

The possibilities of exploring nontraditional datasets with young children

Today's world is characterized by the extensive production of data in different scenarios that everyday citizens need to understand for their informed participation in society. With the increase in the availability of data in a society defined by the industrious production of data, the educational system needs to think of possibilities to bring young children closer to the world of data science. This paper presents a nontraditional data exploration experience with an 8-year-old participant helped by a data visualization tool. A task-based interview was conducted while the participant explored a carbon dioxide emission dataset. This paper studied how the participant interrogates the data, draws inferences and exhibits dispositions. At the end, some reflections are presented when introducing the exploration of nontraditional data in teaching.     

基于关键点的小波提取时间序列近似表示方法

为了克服常见的时间序列近似表示方法参数精确控制不准确而带来的源序列数据表示减损问题,提出一种基于关键点技术的小波变换分解近似表示方法。来自于不同时间序列的仿真实验表明:相比已有的近似表示方法,它保留了原有表示方法的尺度近似系数,摆脱了用户对参数的精确操作控制,在保留住了时序数据的主要特征的同时还极大地实现了时序数据维度的有效约简。     

海量数据的MapReduce相似度检测

针对当前海量数据的相似重复问题,提出了MapReduce下通过SimHash算法检测相似文档的方法:即首先将存储在分布式文件系统的海量文档集进行分类,然后进行特征提取,由SimHash算法生成SimHash指纹和生成Sequence File;最后,计算相似度产生检测结果;通过实验测试可知,提出的检测方法和设计的相似度算法能很好适应海量数据相似检测,并能有效地提高工作效率。     

基于语言输入假说和建构主义理论的大学英语写作教学模式浅探

目前大学英语写作中学生无话可说、缺乏想象力和创造力的现象普遍存在。而有效激发学生英语写作的兴趣,解决创造性思维缺乏的问题,关键在于写作前为学生提供一系列能触发想象力与写作话题相关的问题和线索。主要依据语言输入假说和建构主义理论,探讨写作教学中课前语言最佳输入、课堂输入模式的多样化,提出创建优秀作文库和实行"10+30+5"多形式课堂输入的模式。