共查询到20条相似文献，搜索用时 599 毫秒
1.
《International Journal of Research & Method in Education》2013,36(3):285-308
As applications of multilevel modelling in educational research increase, researchers realize that multilevel data collected in many educational settings are often not purely nested. The most common multilevel non-nested data structure is one that involves student mobility in longitudinal studies. This article provides a methodological review of three statistical methods for handling student mobility in longitudinal studies: a multilevel approach, a cross-classified approach, and a cross-classified multiple membership approach. The strengths and weaknesses of each approach and the essential differences between the three approaches are discussed. The Early Childhood Longitudinal Study Kindergarten Cohort data are analysed to demonstrate the differences in parameter estimates and statistical inference between the three approaches. Potential applications of the three approaches in educational research and beyond and directions for further methodological investigations are discussed. 相似文献
2.
Therese D. Pigott 《Educational Research and Evaluation》2013,19(4):353-383
This paper reviews methods for handling missing data in a research study. Many researchers use ad hoc methods such as complete case analysis, available case analysis (pairwise deletion), or single-value imputation. Though these methods are easily implemented, they require assumptions about the data that rarely hold in practice. Model-based methods such as maximum likelihood using the EM algorithm and multiple imputation hold more promise for dealing with difficulties caused by missing data. While model-based methods require specialized computer programs and assumptions about the nature of the missing data, these methods are appropriate for a wider range of situations than the more commonly used ad hoc methods. The paper provides an illustration of the methods using data from an intervention study designed to increase students’ ability to control their asthma symptoms. 相似文献
3.
YANG Rui-jun XIA Qi PAN Qun-hua WANG Wei-nong LI Ming-lu 《浙江大学学报(A卷英文版)》2006,7(4):493-501
INTRODUCTION Mobile ad hoc networks are under active research focused on issues such as routing, security (Venkatra- man and Agrawal, 2003) and data management (Fan and Zhang, 2004). People have proposes many kinds of security mechanisms such as SAR (Yi et al., 2002), SRP (Papadimitratos and Haas, 2002), ARAN (San- zgiri et al., 2002), ARIADNE (Hu et al., 2005) and SEAD (Hu et al., 2002) for networks. The resource consumptions of security mechanisms are always large in mobile … 相似文献
4.
随着移动自组织网络(MANET)的应用领域日益扩大,要求它必须提供一定的服务质量(QoS)保证,而QoS路由协议是MANET支持QoS的一个关键理论和技术,也是目前的一个研究热点。本文对当前自组织网络的QoS主要路由协议进行了详细的分析与研究,并从路由机制、单向链路的支持、多播功能、QoS参数选择以及节能几个方面进行了比较和分析;最后指出了今后的研究方向。 相似文献
5.
Audrey J. Leroux 《Journal of Experimental Education》2019,87(3):430-448
This study proposes a new model, termed the multiple membership piecewise growth model (MM-PGM), to handle individual mobility across clusters frequently encountered in longitudinal studies, especially in educational research wherein some students could attend multiple schools during the course of the study. A real data set containing some students who switched elementary schools was used to demonstrate and explain the MM-PGM. Parameter and model fit differences were compared between the MM-PGM and two other techniques for handling student mobility: the first school-PGM, which only used school membership at the first measurement occasion, and the delete-PGM, which removed mobile students from the analysis. Results indicated that the three approaches of handling mobile students led to different conclusions about the impact of school-level predictors of growth parameters and the school-level variability in the growth rates. Furthermore, deleting mobile students altered the impact of student-level predictors compared to the other two approaches. 相似文献
6.
葛文英 《安阳师范学院学报》2006,(5):45-48
目前,移动Ad Hoc网络越来越受到人们的重视。在Ad Hoc网络中,路由协议的性能优劣是一个很重要的问题。目前的协议大体可分为两类:表驱动类和按需驱动类路由协议。研究表明:表驱动类的路由协议带来了大量的路由开销,对于网络带宽比较紧张的Ad hoc网络环境,按需路由协议是更好的选择。 相似文献
7.
Linda Leach 《高等教育研究与发展》2016,35(4):772-786
Student engagement has become increasingly important in higher education in recent years. Influenced internationally by government drivers to improve student outcomes, many countries and institutions have participated in surveys such as the National Survey of Student Engagement (NSSE) and its progeny, the Australasian Survey of Student Engagement (AUSSE). Findings from these surveys are used to make comparisons, for example, between disciplines within an institution, and between different institutions. The intention is positive – to generate institutional improvement. However, some researchers are raising issues with the design and use of instruments like the NSSE, particularly as it becomes dominant in countries such as the USA, Canada, Australia, New Zealand, South Africa, China and Ireland. Questions have also been raised about discipline differences in student engagement. This article reports on a study conducted in New Zealand. It draws on data from an AUSSE to answer the question: what can we learn about discipline differences in student engagement from AUSSE data in one institution? It uses analysis of variance and post hoc procedures to identify significant differences between disciplines. Findings show that: there were significant differences between disciplines on all six engagement scales; some discipline differences are influenced by assumptions in the AUSSE; findings on differences between hard and soft disciplines are both similar to and different from previous studies; AUSSE data not be compared across disciplines within an institution; and the AUSSE scales need to go beyond the current focus on measuring students’ behaviours. 相似文献
8.
武静 《武汉职业技术学院学报》2012,11(4):77-81
学生党员发展是高职院校党建工作的重要组成部分。高职院校需立足自身特点,分析学生党员发展存在的问题及其成因,并从完善工作体制,规范工作程序,健全组织机构,强化领导科学管理意识,突出基层工作效力,提高专项经费,加大基层党务理论研究,以保障学生党员发展工作的良性运行。 相似文献
9.
机器人比赛和学生创新能力的培养 总被引：1，自引：0，他引：1
大学生高水平的创新能力是建设创新型国家的人才和技术基础。足球机器人系统是一类典型的多移动机器人合作的对抗系统,机器人足球比赛已受到人工智能和机器人相关领域学者的广泛关注,并逐渐成为一个标准问题。分析机器人比赛在培养大学生创新能力方面所起的重要作用,阐述机器人系统的基本知识。通过参加机器人比赛,使学生获取更多的知识并学会分析问题和解决问题的方法,在创新能力方面得到有效的训练和全面健康的发展。 相似文献
10.
Julie A. Bianchini 《Cultural Studies of Science Education》2011,6(4):871-882
In this response to Konstantinos Alexakos, Jayson K. Jones, and Victor H. Rodriguez’s study, I discuss ways attending to student
membership in groups can both inform research on equity and diversity in science education and improve the teaching of science
to all students. My comments are organized into three sections: how underrepresented students’ experiences in science classrooms
are shaped by their peers; how science teachers can help students listen to and learn from one another; and how the subject
matter can invite or discourage student participation in science. More specifically, I underscore the need for teachers and
students to listen to one another to promote student learning of science. I also highlight the importance of science education
researchers and science teachers viewing students both as individuals and as members of multiple groups; women of color, for
example, should be understood as similar to and different from each other, from European American women and from ethnic minorities
in general. 相似文献
11.
从通信部门所担负的任务出发,建立通信部门移动自组网抗毁性模型,对两节点通信网络直接连接的两个简单网络进行抗毁性评估,同时深入研究了上述网络两节点必须中转一次的抗毁性评估方法． 相似文献
12.
13.
Philanthropists, researchers, policymakers, and practitioners are increasingly focused on a college completion crisis in the United States. Collectively and independently, they have called for increasing the number of adults with postsecondary certificates and degrees as a national imperative. Using the 2007 administration of the Community College Survey of Student Engagement (CCSSE), this article explores the statistical relationships between student engagement, as measured by the CCSSE, and institutional graduation rates reported to the Integrated Postsecondary Education Data System (IPEDS). Both bivariate correlations and hierarchical multiple regression analyses yielded results that reinforce the salience of student engagement as an important predictor of college completion. Specifically, the CCSSE student engagement benchmarks of active and collaborative learning and support for learners are positive predictors of institutional graduation rates. The article concludes with suggestions around instructional practices and institutional policies to consider for community college leaders committed to the completion agenda. 相似文献
14.
Iryna Y. Johnson 《Research in higher education》2011,52(8):761-785
This study addresses methodological problems surrounding existing research on exposure to contingent instructors and student
outcomes. By applying non-aggregated and aggregated measures of exposure to contingent instructors to the same data, this
analysis demonstrates that effects of commonly used measures of exposure to contingent instructors have little to do with
actual contingent instructor effects on student outcomes. Two multi-level approaches—cross-classified and multiple membership
models—are applied in the single-institution analysis of faculty status effect on student outcomes—grades and first year retention.
The analysis showed no variability in student retention and a significant variability in grades by faculty characteristics.
Compared to their tenured and tenure-track peers, contingent instructors are more likely to assign higher grades, which may
lead to lowered levels of academic challenge and student motivation to do their best work. 相似文献
15.
Although collecting data from multiple informants is highly recommended, methods to model the congruence and incongruence between informants are limited. Bauer and colleagues suggested the trifactor model that decomposes the variances into common factor, informant perspective factors, and item-specific factors. This study extends their work to the trifactor mixture model that combines the trifactor model and the mixture model. This combined approach allows researchers to investigate the common and unique perspectives of multiple informants on targets using latent factors and simultaneously take into account potential heterogeneity of targets using latent classes. We demonstrate this model using student self-rated and teacher-rated academic behaviors (N = 24,094). Model specification and testing procedures are explicated in detail. Methodological and practical issues in conducting the trifactor mixture analysis are discussed. 相似文献
16.
一种增强移动自组网Internet连接的改进型方案 总被引：1，自引：0，他引：1
针对移动自组网因单向链路以及盲目转播网关发现分组而造成的与Internet互联性能下降,提出了一种增强型互联方案.同时结合了先应和后应网关发现策略优点的混合网关发现策略被用来获取良好的Internet连接并保持低开销.而通过交换携带有额外增加的对称邻居节点列表和非对称邻居节点列表字段的AODV hello分组,单向链路得以从路由计算中予以清除而广播风暴也同时得到抑制.基于ns-2的仿真结果表明此改进型Internet连接方案在单向链路数量及节点移动速度均变化的应用环境下能取得较其他方案为优的互联性能. 相似文献
17.
Pavlo D. Antonenko Serkan Toy Dale S. Niederhauser 《Educational technology research and development : ETR & D》2012,60(3):383-398
Cluster analysis is a group of statistical methods that has great potential for analyzing the vast amounts of web server-log data to understand student learning from hyperlinked information resources. In this methodological paper we provide an introduction to cluster analysis for educational technology researchers and illustrate its use through two examples of mining click-stream server-log data that reflects student use of online learning environments. Cluster analysis can be used to help researchers develop profiles that are grounded in learner activity??like sequence for accessing tasks and information, or time spent engaged in a given activity or examining resources??during a learning session. The examples in this paper illustrate the use of a hierarchical clustering method (Ward??s clustering) and a non-hierarchical clustering method (k-Means clustering) to analyze characteristics of learning behavior while learners engage in a problem-solving activity in an online learning environment. A discussion of advantages and limitations of using cluster analysis as a data mining technique in educational technology research concludes the article. 相似文献
18.
William D. Schafer Shu Jing Yen Talsima Rahman 《Journal of Experimental Education》2013,81(3):239-250
Three residual-based methods for indexing school effectiveness were compared using data from elementary schools in Maryland. Two of the methods were regression-based procedures at the school level, and 1 was a hierarchical linear model approach, with Level 1 at the student level and Level 2 at the school level. The 2 methods were applied to a data source in which schools were evaluated separately at Grades 3 and 5 using 3 forms of a statewide performance assessment that were administered to randomly formed groups within each school. The hierarchical linear model approach had higher stability across test forms, but the stabilities of the 1-level formulations were almost as high. The authors concluded that 1-level approaches are viable alternatives when the added data necessary for the hierarchical linear model approach are unavailable. 相似文献
19.
《Journal of research on educational effectiveness》2013,6(2):189-211
Abstract Applied researchers often find themselves making statistical inferences in settings that would seem to require multiple comparisons adjustments. We challenge the Type I error paradigm that underlies these corrections. Moreover we posit that the problem of multiple comparisons can disappear entirely when viewed from a hierarchical Bayesian perspective. We propose building multilevel models in the settings where multiple comparisons arise. Multilevel models perform partial pooling (shifting estimates toward each other), whereas classical procedures typically keep the centers of intervals stationary, adjusting for multiple comparisons by making the intervals wider (or, equivalently, adjusting the p values corresponding to intervals of fixed width). Thus, multilevel models address the multiple comparisons problem and also yield more efficient estimates, especially in settings with low group-level variation, which is where multiple comparisons are a particular concern. 相似文献
20.
为了满足战后扫雷的实际需求,针对现有雷场探测技术的不足,设计基于多源信息同步探测、具有雷场扫描探测和疑似目标探测两种工作模式的雷场探测系统。系统由一个设置在安全位置的探测控制主机和多个具有飞行、探测功能的探测分机组成。采用基于LoRa的无线通信技术,进行LoRa无线通信模块硬件电路设计与动态自组网方式设计,并以Mesh网络拓扑实现自组网。最后,在雷场探测模拟试验场环境下对系统进行测试,在不同通信距离条件下对系统传输功率及丢包率的测试结果表明,该系统能满足雷场探测过程中的多任务处理要求。 相似文献