Modeling Growth in Electronic Learning Environments Using a Longitudinal Random Item Response Model

In educational environments, monitoring persons' progress over time may help teachers to evaluate the effectiveness of their teaching procedures. Electronic learning environments are increasingly being used as part of formal education and resulting datasets can be used to understand and to improve the environment. This study presents longitudinal models based on the item response theory (IRT) for measuring persons' ability within and between study sessions in data from web-based learning environments. Two empirical examples are used to illustrate the presented models. Results show that by incorporating time spent within- and between-study sessions into an IRT model; one is able to track changes in ability of a population of persons or for groups of persons at any time of the learning process.     

The Multidimensionality of Measurement Bias in High-Stakes Testing: Using Machine Learning to Evaluate Complex Sources of Differential Item Functioning

Test developers and psychometricians have historically examined measurement bias and differential item functioning (DIF) across a single categorical variable (e.g., gender), independently of other variables (e.g., race, age, etc.). This is problematic when more complex forms of measurement bias may adversely affect test responses and, ultimately, bias test scores. Complex forms of measurement bias include conditional effects, interactions, and mediation of background information on test responses. I propose a multidimensional, person-specific perspective of measurement bias to explain how complex sources of bias can manifest in the assessment of human knowledge, skills, and abilities. I also describe a data-driven approach for identifying key sources of bias among many possibilities—namely, a machine learning method commonly known as regularization.     

How students reason about matter flows and accumulations in complex biological phenomena: An emerging learning progression for mass balance

In recent years, there has been a strong push to transform STEM education at K-12 and collegiate levels to help students learn to think like scientists. One aspect of this transformation involves redesigning instruction and curricula around fundamental scientific ideas that serve as conceptual scaffolds students can use to build cohesive knowledge structures. In this study, we investigated how students use mass balance reasoning as a conceptual scaffold to gain a deeper understanding of how matter moves through biological systems. Our aim was to lay the groundwork for a mass balance learning progression in physiology. We drew on a general models framework from biology and a covariational reasoning framework from math education to interpret students' mass balance ideas. We used a constant comparative method to identify students' reasoning patterns from 73 interviews conducted with undergraduate biology students. We helped validate the reasoning patterns identified with >8000 written responses collected from students at multiple institutions. From our analyses, we identified two related progress variables that describe key elements of students' performances: the first describes how students identify and use matter flows in biology phenomena; the second characterizes how students use net rate-of-change to predict how matter accumulates in, or disperses from, a compartment. We also present a case study of how we used our emerging mass balance learning progression to inform instructional practices to support students' mass balance reasoning. Our progress variables describe one way students engage in three dimensional learning by showing how student performances associated with the practice of mathematical thinking reveal their understanding of the core concept of matter flows as governed by the crosscutting concept of matter conservation. Though our work is situated in physiology, it extends previous work in climate change education and is applicable to other scientific fields, such as physics, engineering, and geochemistry.     

论运动素质转移与运动项目迁移的关系* ——以健美操与体育舞蹈、体操为例

运动素质是可以相互转移的,各个运动项目需要的身体素质不尽相同,但他们之间都是可以相互转移的。通过描述了多个运动项目之间的身体素质之间的关系和转移,主要介绍了竞技健美操与体育舞蹈之间素质的转移,说明,每个项目需要的身体素质不同,运动员都要朝着正迁移的方向来进行训练。     

湖北省竞技体育发展中存在的问题及对策

对湖北省竞技体育的现状进行分析,指出目前发展中存在的诸多问题,并提出相应的对策：实施竞技体育规划战略;提升竞技人力资源水平;加强重点项目的建设、优化及布局;提高教练员的综合能力和素质等。     

影响我国优秀运动员商业价值的因素分析

对取得过辉煌运动成绩和良好商业收入的运动员的共同特征进行分析,结果表明：我国优秀运动员商业价值的影响因素包括运动员从事的体育项目、运动员的成绩与荣誉、运动员的运动寿命、运动员的外在形象、运动员的社会形象、体育管理制度、运动员的商业开发与管理等。     

一种移动话务的潮汐效应解决方案

本文提出了一种移动话务的潮汐效应智能化解决方案,提出了一种基带资源池技术,以达到提高基站利用率和降低建网成本、降低能耗的目的。     

Psychometric Properties of IRT Proficiency Estimates

Psychometric properties of item response theory proficiency estimates are considered in this paper. Proficiency estimators based on summed scores and pattern scores include non-Bayes maximum likelihood and test characteristic curve estimators and Bayesian estimators. The psychometric properties investigated include reliability, conditional standard errors of measurement, and score distributions. Four real-data examples include (a) effects of choice of estimator on score distributions and percent proficient, (b) effects of the prior distribution on score distributions and percent proficient, (c) effects of test length on score distributions and percent proficient, and (d) effects of proficiency estimator on growth-related statistics for a vertical scale. The examples illustrate that the choice of estimator influences score distributions and the assignment of examinee to proficiency levels. In particular, for the examples studied, the choice of Bayes versus non-Bayes estimators had a more serious practical effect than the choice of summed versus pattern scoring.     

Application of Think Aloud Protocols for Examining and Confirming Sources of Differential Item Functioning Identified by Expert Reviews

This paper demonstrates and discusses the use of think aloud protocols (TAPs) as an approach for examining and confirming sources of differential item functioning (DIF). The TAPs are used to investigate to what extent surface characteristics of the items that are identified by expert reviews as sources of DIF are supported by empirical evidence from examinee thinking processes in the English and French versions of a Canadian national assessment. In this research, the TAPs confirmed sources of DIF identified by expert reviews for 10 out of 20 DIF items. The moderate agreement between TAPs and expert reviews indicates that evidence from expert reviews cannot be considered sufficient in deciding whether DIF items are biased and such judgments need to include evidence from examinee thinking processes.     

专项课对体质发育的影响

本文对山西师大文、理科非体育专业学生,经1986年至1995年近十年体育后期专项化改革实验,从中抽样选出86级男生篮球、排球两个专项班各30人,女生武术、健美两个专项班各30人为样本,对经过普通体育课、专项体育课、体育选修课,自修体育课的四年大学体育学习与锻炼的学生进行测定,获得身体形态、机能发育和素质增长的多项指标。