Examining the Rule of Thumb of Not Using Multilevel Modeling: The “Design Effect Smaller Than Two” Rule

Educational researchers commonly use the rule of thumb of “design effect smaller than 2” as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models (which differ in the location of the clustering effect). With a 3 (design effect) × 5 (cluster size) × 4 (number of clusters) Monte Carlo simulation study we found that the rule should not be applied when researchers: (a) are interested in the effects of higher-level predictors, or (b) have a cluster size less than 10. Implications of the findings and limitations of the study are discussed.     

Reexamining the Impact of Nonnormality in Two-Group Comparison Procedures

The authors performed a Monte Carlo simulation to empirically investigate the robustness and power of 4 methods in testing mean differences for 2 independent groups under conditions in which 2 populations may not demonstrate the same pattern of nonnormality. The approaches considered were the t test, Wilcoxon rank-sum test, Welch-James test with trimmed means and Winsorized variances, and a nonparametric bootstrap test. Results showed that the Wilcoxon rank-sum test and Welch-James test with trimmed means and Winsorized variances were not robust in terms of type I error control when the 2 populations showed different patterns of nonnormality. The nonparametric bootstrap test provided power advantages over the t test. The authors discuss other results from the simulation study and provide recommendations.     

高职行业英语课程开发探究

目前高职院校在英语教学方面存在着亟需解决的问题,行业英语能有效地弥补基础英语与专业英语之间的差距。在对课程性质、学生情况、调研情况等综合因素分析的基础上,提出高职行业英语课程的目标设置,并从四个方面,即课程设置、教材开发、场景模拟和教师队伍建设四个方面对高职行业英语课程进行开发。     

我国冰雪旅游发展的系统动力学仿真研究

目的:预测分析冰雪旅游业下一阶段的发展潜力,以此来规避风险、降低损失,实现冰雪旅游业发展的最大化效益。方法:利用系统动力学方法,借助Vensim PLE软件,构建我国冰雪旅游发展的系统动力学模型,仿真分析子系统中各影响因素之间的相互作用关系并探究冰雪旅游发展的动力机制。结果:增加潜在旅游者数量、加大宣传力度、加强基础设施建设投入金额、加大投资额度等发展策略均能不同程度地促进冰雪旅游发展;增加潜在旅游者数量、加大投资额度发展策略是实现2022年“三亿人参与冰雪运动”总目标的有力保证;以2022年为时间节点,2020—2022年增加潜在旅游消费者是首选的发展策略;2022年以后加强冰雪旅游投资额度是首选的发展策略。结论:未来冰雪旅游的发展可以通过控制潜在旅游者数量、加大投资额度及其相关因素,有效实现冰雪旅游的可持续发展。     

野外地质实习虚拟仿真实验教学平台建设与思考

野外实习是培养合格地质人才的重要环节和专业特色,对培养学生兴趣、巩固专业知识、提高实践能力等有着不可替代的作用。然而传统野外地质教学实习中存在效率低、成本高、互动性和共享性差等问题,虚拟仿真教学很好地弥补了此缺陷。通过以汉中梁山野外地质实习基地为例,介绍了长安大学地质学类专业野外地质实习的发展现状,实习目的和任务,分析了传统野外地质实习存在的问题,探讨了汉中梁山野外地质实习虚拟仿真教学平台建设的思路和拟解决的关键问题。     

Comsol仿真软件在“电磁兼容”课程实验中的应用

随着电子产品中的电磁兼容问题越来越受到关注,“电磁兼容”理论已成为电气技术人员必备的专业基础知识,也是测控专业的学生不可或缺的能力之一。针对“电磁兼容”理论中概念抽象、公式多、学生理解困难等问题,通过优化实验内容,采取基于问题需求牵引式、互动式的教学方式,将Comsol仿真软件引入学生的实验中去。以“飞机天线串扰电磁兼容仿真实验”设计为例,说明将仿真软件用于电磁兼容课程实验的全过程。结果表明,该实验方式从多角度综合考虑了电磁兼容性的问题,有利于培养学生的理论知识,以及分析问题、解决问题的能力。     

Learning statistics with interactive pictures using R Shiny: Generally preferred,but not generally advantageous

Constructing interactive web apps has become more accessible for instructors, for example, by using the R package Shiny. Here we explored learners' preferences and the efficiency of interactive simulations versus static pictures in acquiring statistics knowledge of Cohen's d and standard normal distribution. Results revealed that students' spontaneous interaction with pictures was infrequent (pilot study, N = 26). While prompts (Exp. 1, N = 152) effectively ensured the manipulation of simulations, student exposure to interactive simulations led to longer learning times though similar test performance compared with student exposure to static pictures. Multiple interactive representations led to lower test performance than single interactive and static representations (Exp. 2, N = 117). Though no advantage was gained regarding learning outcomes, participants preferred the interactive variant (Exp. 3, N = 119). Taken together, this study demonstrates that the superiority of interactive pictures cannot be assumed to hold in general. Further work should evaluate how mental model construction can be effectively scaffolded by interactive simulations.     

大型虚拟仿真训练中心的建设与研究

虚拟仿真技术可以模拟现实世界的真实系统,学生可以进行机械设计、零部件建模与整体装配、艺术设计与建筑设计,可以虚拟特殊领域的实验,如化工爆破、电力系统的极限运行状态等现实难于进行的实验操作,有助于培养学生的创新实践能力,同时具有成本低、效率高、安全性好的特点。     

基于Matlab的夫兰克-赫兹实验的计算机模拟

夫兰克-赫兹实验是至今探索原子结构的重要手段之一。本文基于Matlab模拟夫兰克-赫兹实验,研究阴极射线管电压和拒斥电压对电流曲线的影响,并分析了其原因。