试论皮亚杰的运算逻辑

皮亚杰认为抽象模式是心理学因果解释的一种形式,文章认为皮亚杰所开创的运算逻辑是儿童实际思维发展机制的形式化模型,也是解释儿童认知结构转换规律的抽象模式。     

不同语料下基于LDA主题模型的科学文献主题抽取效果分析

[目的/意义]潜在狄利克雷分布(Latent Dirichlet Allocation,LDA)在科技情报分析中用来发现学科主题、挖掘研究热点以及预测研究趋势等。对常见的科学文献文本语料库(关键词、摘要、关键词+摘要)进行LDA主题抽取效果的评价,以揭示不同语料库的主题抽取效果,提高LDA在科技情报分析中的应用效果。[方法/过程]对上述3种语料库下的LDA主题模型进行对比研究,采用基于查全率、查准率、F值以及信息熵的定量分析和基于主题抽取的广度和主题粒度的定性分析相结合的方法对主题抽取效果进行评价。[结果/结论]通过国内风能领域的科学文献数据实证研究发现,无论是从定量分析还是从定性分析来看,摘要和关键词+摘要作为语料的LDA主题抽取的效果均优于关键词作为语料的LDA主题抽取效果,并且前者在主题抽取的广度方面表现更好,而后者抽取的主题粒度更细。     

论历史时期汉水流域的文化政治地位

李家村与龙岗等仰韶文化遗存的分布表明 ,汉水流域是华夏文明的重要发祥地之一。对建都秦岭以北关中平原的周秦汉唐等王朝来说 ,汉水流域一直是第一政治后方 ,起着重要的政治缓冲和后院屏障作用 ;汉水流域历史上曾几度辉煌又几度衰落 ,代表着内陆腹地区域发展的一个典型 ;而作为沟通与中原、中南与西部的交通大动脉 ,又与中国的西部的开发具有重要意义。     

科研型数学教师及其培养

国际经济、科技、人才的竞争正推动着教育的改革。教育改革的关键因素在于合格的、新型教师的培养。科研型教师是指既能教学，又能进行数学及数学教育研究的教师。科研型教师应具备3项条件：转变观念，更新意识，提高能力。科研型数学教师是新时代数学教育的需要，要实行理论学习、实践探索和科学研究三位一体的教师培训途径。教养科研型教师需要解决“为何搞科研”、“如何搞科研”和“研究什么”3个问题。     

Explaining match outcome in elite Australian Rules football using team performance indicators

The relationships between team performance indicators and match outcome have been examined in many team sports, however are limited in Australian Rules football. Using data from the 2013 and 2014 Australian Football League (AFL) regular seasons, this study assessed the ability of commonly reported discrete team performance indicators presented in their relative form (standardised against their opposition for a given match) to explain match outcome (Win/Loss). Logistic regression and decision tree (chi-squared automatic interaction detection (CHAID)) analyses both revealed relative differences between opposing teams for “kicks” and “goal conversion” as the most influential in explaining match outcome, with two models achieving 88.3% and 89.8% classification accuracies, respectively. Models incorporating a smaller performance indicator set displayed a slightly reduced ability to explain match outcome (81.0% and 81.5% for logistic regression and CHAID, respectively). However, both were fit to 2014 data with reduced error in comparison to the full models. Despite performance similarities across the two analysis approaches, the CHAID model revealed multiple winning performance indicator profiles, thereby increasing its comparative feasibility for use in the field. Coaches and analysts may find these results useful in informing strategy and game plan development in Australian Rules football, with the development of team-specific models recommended in future.     

Effects of psychosocial variables in the similarity and interdependence of physical activity levels among adolescent best friend dyads

Given that physical activity (PA) tends to decrease with age during adolescence, addressing factors that affect change is important. This study examined the similarity and interdependence of PA as influenced by psychosocial factors among adolescent best friend dyads. A total of 660 adolescents, representing 330 best friend dyads, completed questionnaires with regard to PA, sitting time, perceived exercise benefits and barriers, physical self-perception and social support for PA. Dyads were also identified as reciprocal and non-reciprocal best friends; reciprocal means that both considered each other best friends and non-reciprocal were those in which only one considered the other a best friend. Data were analysed using a hierarchical linear model framework. Results indicated significant similarities between reciprocal best friend dyads for PA and sitting time, and for sitting time in non-reciprocal best friends (P values <.01). Psychosocial variables were associated with PA in reciprocal best friend dyads and with sitting time in reciprocal and non-reciprocal best friend dyads. Best friend gender, regular sports practice of the person, perceived exercise barriers of the best friend and best friend social support were the best predictors for PA.     

A comparison of methods to determine bilateral asymmetries in vertical leg stiffness

Whilst the measurement and quantification of vertical leg stiffness (K_vert) asymmetry is of important practical relevance to athletic performance, literature investigating bilateral asymmetry in K_vert is limited. Moreover, how the type of task used to assess K_vert may affect the expression of asymmetry has not been properly determined. Twelve healthy males performed three types of performance tasks on a dual force plate system to determine K_vert asymmetries; the tasks were (a) bilateral hopping, (b) bilateral drop jumping and (c) unilateral drop jumping. Across all the three methods, K_vert was significantly different between compliant and stiff limbs (P < 0.001) with a significant interaction effect between limb and method (P = 0.005). Differences in K_vert between compliant and stiff limbs were ?5.3% (P < 0.001), ?21.8% (P = 0.007) and ?15.1% (P < 0.001) for the bilateral hopping, bilateral drop jumping and unilateral drop jumping methods, respectively. All the three methods were able to detect significant differences between compliant and stiff limbs, and could be used as a diagnostic tool to assess K_vert asymmetry. Drop jumping tasks detected larger K_vert asymmetries than hopping, suggesting that asymmetries may be expressed to a greater extent in acyclic, maximal performance tasks.     

广义马氏过程及其熵率

讨论了k步广义马氏过程及其时间不变性和平稳性，给出了熵率的两种定义，说明了其等价性，还给出了平稳的广义马氏链熵率的计算公式．     

非平衡多阶段物流系统建模与优化方法

首先提出了参数化界面分布的新概念,将一个非平衡多阶段物流系统转化为多个相互独立的单一阶段物流系统,然后采用Prüfer数对每个阶段上的物流模式进行编码.通过一种改进的解码方法,任何一个随机产生的Prüfer数都能够被解码为一个与物流系统的节点容量相匹配的可行的物流模式.基于这2点创新,建立了一种新的基于参数化界面分布和Prüfer数编码的系统建模方法,相应的遗传算法称为PIP-GA方法.与st-GA方法相比,PIP-GA不但具有更好的优化结果,而且需要的计算时间更少;虽然所需的存储空间有所增加,PIP-GA仍然是一种有效而稳健的非平衡多阶段物流系统建模与优化方法.     

贯彻“以德治国”方略坚持“以德育人”为先

“以德治国”,是江泽民同志提出的重要治国方略,结合学校实际贯彻“以德治国”方略,就是要坚持“以德育人”为先,既要牢固“首位、思想,强化“师表”意识;又要着力“课堂”教学;狠抓“养成”教育,营造“环境”氛围,构建“机制”育人。