Examining Intermediate Omitted Levels in Hierarchical Designs via Latent Variable Modeling

This article outlines an interval estimation procedure that can be used in a 3-level setting to evaluate the proportion of outcome variance attributable to the second level of clustering. The method is useful for examining the necessity of including a possibly omitted intermediate level of nesting in analyses of data from a multilevel study, and represents an informative addendum to current statistical tests of second-level variance. The approach is developed within the framework of latent variable modeling and can be used as an aid in the process of choosing between 2-level and 3-level models in a hierarchical design. The discussed procedure is illustrated with an empirical example.     

Making sense of learner and learning Big Data: reviewing five years of Data Wrangling at the Open University UK

Most distance learning institutions collect vast amounts of learning data. Making sense of this ‘Big Data’ can be a challenge, in particular when data are stored at different data warehouses and require advanced statistical skills to interpret complex patterns of data. As a leading institute on learning analytics, the Open University UK instigated in 2012 a Data Wrangling initiative. This provided every Faculty with a dedicated academic with expertise data analysis and whose task is to provide strategic, pedagogical and sense-making advice to staff and senior management. Given substantial changes within the OU (e.g. new Faculty structure, real-time dashboards, two large-scale adoptions of predictive analytics approaches, increased reliance on analytics), this embedded case study provides an in-depth review of lessons learned of five years of data wrangling. We will elaborate on the design of the new structure, its strengths and potential weaknesses, and affordances to be adopted by other institutions.     

How to measure research efficiency in higher education? Research grants vs. publication output

An ongoing debate in the literature on the efficiency of higher education institutions concerns the indicator for research output for use in empirical analysis. While several studies have chosen to use the number of publications as this indicator, others rely on the amount of research grants. The present study investigates whether both measures lead to a similar assessment of universities. In addition, the number of publications belonging to the 10% and 1% most frequently cited papers in the corresponding subject category and publication year are evaluated. We show that there is a high correlation of efficiency values between the estimations using these indicators. This correlation is slightly higher when the efficiency values result from a data envelopment analysis than when they are determined with a stochastic frontier analysis. The results of this study provide helpful guidelines for researchers evaluating the efficiency of universities and are valueable for decision-makers in science policy.     

科学计算中辅助技术探讨

科学计算中辅助技术是计算机科学发展到一定阶段而提出的一个很有实际意义的课题．本文针对科学计算过程探讨了工程数据库技术和可视计算技术     

线性网络幅频特性的自动测量

介绍了利用精密二极管检波测量线性阻抗网络幅频特性的方法以及由计算机数据采集系统组成的自动测量装置，数据测量结果分析表明，该方法的测量误差在3％以内。完全可代替常规的交流测量法，该方法配合高稳定性、快速跟踪的压控振荡器VCO可实现宽频范围内的快速扫频自动测量。     

Web日志挖掘技术在校园网信息处理中的应用研究

随着校园网的快速发展,产生了海量信息,怎样利用数据挖掘技术根据校园网用户的访问日志挖掘出有价值的信息,是值得深入研究的。作者首先介绍了Web日志挖掘技术的主要内容,再深入研究在校园网信息处理方面的应用,重点以遵义师范学院校园网为实例,使用关联规则进行研究分析,探讨出用户的兴趣与偏好,从而更好地为学校教学管理服务。     

XML安全技术在石材信息检索系统中的应用

XML是一种面向数据的标记语言,具有结构严谨,简单易用等优点,己成为数据交换的标准．本文首先阐述了XML的特点,语言规范和应用领域,然后从XML加密,XML数字签名,以及XML公钥管理技术三个方面对XHL的安全技术进行了讨论。并组建了XML数据交换平台架构．在此基础上,给出了XML安全技术在石材信息检索系统中的应用．以及系统的需求分析和功能模块设计．     

基于时间序列的退化型产品可靠性评估方法

在不假定退化轨道的基础上,提出利用时间序列的方法,使用ARIMA模型对退化数据进行建模,拟合其退化规律,预测失效寿命,进而进行可靠性评估.并给出实例,说明该方法具有较好的适用性和有效性.     

基于行波测距的电缆故障测试装置的研究

介绍基于行波测距的电缆故障测试装置的原理、结构及其设计方案。选择C类方法进行实现,设计脉冲发送电路及脉冲接收电路,在高速数据采集的支持下,完成对电缆故障定位。     

基于GIS的中小学应急救援指挥系统的设计

以石家庄市为例,以GIS为平台,结合数据库系统,研究开发了中小学应急救援指挥系统.分析了此系统设计的原则、系统架构及特色、系统功能模块和系统的数据库设计,此系统的使用有利于在突发状态下进行通讯指挥,最大程度地预防和减小灾害造成的损失.