Psychometric Properties of IRT Proficiency Estimates     

Michael J. Kolen  Ye Tong 《Educational Measurement》2010,29(3):8-14

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.  相似文献   

‘Personal’and‘critical’? Exam criteria,engagement with texts,and real readers’ responses     

Fiona Richards-Kamal 《English in Education》2008,42(1):53-69

This article explores how exam criteria require pupils to engage with texts at once 'personally' and 'critically'. It theorises this dichotomy, suggesting problems it presents in a classroom. Observing that dwindling opportunities for creative writing impede personal engagement, it considers the possibilities suggested by the imaginative writings of two pupils for resolving the dichotomy.  相似文献   

基于ANYSYS的电路板组件的跌落仿真     

毛兰斌 《苏州市职业大学学报》2007,18(3):73-75

基于ANSYS/LS-DYNA的结构动力分析模块,对印刷电路板组件进行了跌落仿真分析,模拟了整个跌落撞击过程,分析不同边界条件以及封装件的布置方式对电路板组件动态响应的影响。  相似文献   

低氧训练过程中大鼠体重及能量代谢的变化   总被引：1，自引：0，他引：1  

黄徐根  冯连世  徐建方  路瑛丽 《体育科学》2007,27(10):61-68,96

目的：研究低氧训练过程中大鼠体重、体成分、能量摄入及静息代谢率的变化，初步探讨低氧训练过程中大鼠体重变化与能量代谢变化间关系。方法：经过适应性训练筛选出的50只SD大鼠平均分为5组，保证每组大鼠体重基本一致，随机分为常氧安静组、常氧限食组、常氧训练组、低氧安静组、低氧训练组。训练组大鼠采用水平动物跑台进行耐力训练6周。试验期间每周称量大鼠体重，每3天称量一次大鼠食物摄入量。试验前、试验1周、3周、5周末测定大鼠静息代谢率，试验后处死大鼠并剥离其肾周、腹股沟脂肪及腓肠肌，称量其重量。结果：低氧训练组大鼠体重增幅除在第6周末与常氧训练组无显著性差异外，均显著性低于其他试验组，试验前3周其体重出现负增长。试验后低氧训练组大鼠肾周及腹股沟脂肪总含量显著低于其他试验组，而腓肠肌重量与其他组无显著性差异。低氧训练组大鼠试验期间总食物摄入量较其他各组大鼠低，尤其在前3周。低氧训练组大鼠静息代谢率先上升而后逐渐下降，至试验3周末时仍高于试验前值，试验5周末时降至低于试验前值（差异不显著），而除低氧安静组外的其他组大鼠静息代谢率则持续下降，至试验5周末时均显著性低于试验前水平。结论：从减缓体重增加幅度及对体成分的影响角度看，低氧训练减体重的效果优于限制饮食、耐力训练及低氧暴露。低氧训练过程中食物摄入量减少及静息代谢率增加可能是大鼠体重增长减缓的原因。  相似文献   

造成运动损伤的心理和社会因素分析   总被引：3，自引：0，他引：3  

吴璋 《体育科学研究》2001,5(4):27-28

对运动队的运动损伤因素进行调查,发现运动员的应激反应、个性特点、运动损伤史、心理活动、环境等心理和社会等因素也是引起损伤的重要因素,提示在运动训练中应注重运动员对这些因素的反应以及开展对这些因素影响的适应和调控训练.  相似文献   

当今世界男子100m再创新纪录的突破口   总被引：1，自引：0，他引：1  

郭洪波  徐富君  许世岩 《武汉体育学院学报》2001,35(1):101-102

用灰色数学法分析了第3、第6届世界田径锦标赛100m跑的技术参数，显示起跑反应和0～20m段的加速训练、最大速度能力和高速度保持能力的训练是再创纪录的突破口。  相似文献   

Identifying families with complex needs after an initial child abuse investigation: A comparison of demographics and needs related to domestic violence,mental health,and substance use     

《Child abuse & neglect》2017

Families with complex needs related to domestic violence, mental health, and substance use have some of the worst child protective services (CPS) outcomes. Although many of these families are identified during a CPS investigation and subsequently referred to home-based postinvestigation services (HBPS), many are re-reported to CPS, so it is important to understand the postinvestigation experiences of this vulnerable group. Therefore, this study compared families with and without complex needs to understand their uniquedemographics, needs, and postinvestigation outcomes.The sample consisted of 2008 caregivers who received HBPS following an initial CPS investigation. The Family Assessment Form (FAF) was used to measure family functioning in eight domains using a 1–5 scale with higher ratings representing worse functioning. Complex needs were indicated by a mean FAF score of 3 or higher for either domestic violence, mental health, or substance use. Using Pearson chi-square analyses and two-sample t-tests, comparisons were made between families with (n = 836) and without (n = 1172) complex needs. Half of caregivers with complex needs had a history of abuse, 25% had three to five needs, and nearly half had six to eight needs; 90% of caregivers without complex needs had zero to two needs. Furthermore, caregivers with complex needs had higher mean scores for concrete, educational, and clinical needs. These findings highlight the importance of recognizing variation among families referred to HBPS and accurate screening to ensure that families with complex needs are offered and receive services matched to their unique characteristics and needs.  相似文献   

Assessing the Sensitivity of Weighted Least Squares Model Fit Indexes to Local Dependence in Item Response Theory Models     

Anne Corinne Huggins-Manley  HyunSuk Han 《Structural equation modeling》2017,24(3):331-340

Given the relationships of item response theory (IRT) models to confirmatory factor analysis (CFA) models, IRT model misspecifications might be detectable through model fit indexes commonly used in categorical CFA. The purpose of this study is to investigate the sensitivity of weighted least squares with adjusted means and variance (WLSMV)-based root mean square error of approximation, comparative fit index, and Tucker–Lewis Index model fit indexes to IRT models that are misspecified due to local dependence (LD). It was found that WLSMV-based fit indexes have some functional relationships to parameter estimate bias in 2-parameter logistic models caused by violations of LD. Continued exploration into these functional relationships and development of LD-detection methods based on such relationships could hold much promise for providing IRT practitioners with global information on violations of local independence.  相似文献   

第五方物流理论在应急响应时效优化中的应用     

王术峰 《科技管理研究》2016,(9)

根据第五方物流系统优化理论,对第五方物流系统进行优化,构建第五方物流模型,包括第五方物流体系功能结构模型和第五方物流信息系统结构模型,从而建立应急物流保障体系,并对应急响应时效优化项目进行实证分析,对创新协同服务应急物流组织模式、运营模式、保障模式、服务模式的可能性进行具体的研究。实证分析结果表明 ,可以实现应急物流保障体系系统优化的目标,为客户提供供应链系统集成、流程优化和资源协同服务。  相似文献   

Model order reduction using response-matching technique     

S. Mukherjee  Satakshi 《Journal of The Franklin Institute》2005,342(5):503-519

A method for model order reduction is proposed using response-matching technique. The step and impulse inputs have been considered. All types of pole configurations in the original high-order and reduced low-order system are included in this paper like real, complex and repeated. The proposed method is comparable in quality with similar existing methods and is capable of generating a reduced-order model with a desired pole pattern.  相似文献