Academic tracking is related to gains in students' intelligence over four years: Evidence from a propensity score matching study

Ability grouping or tracking during secondary schooling is widespread. Previous research shows academic track schools are more successful than non-academic track schools in teaching mathematics, reading and foreign languages. Reasons include a more favorable student composition and higher instructional quality. However, there is less evidence that between track differences are even large enough to differentially affect the students' cognitive development. We used data from a large Hamburg panel study to test this hypothesis (N = 8628). By employing several propensity score matching algorithms we formed parallelized samples of academic track and either non-academic track students or comprehensive school students. After four years of tracking, academic track students showed considerably higher intelligence scores than their counterparts at the non-academic tracks and slightly higher scores than students at the comprehensive schools. Our results underline the importance of a cognitively stimulating learning environment in school to support students' cognitive development.     

GP S软件接收机跟踪算法研究

全球定位系统（GPS）软件接收机被广泛应用于卫星信号的精确定位。在接收机跟踪算法中,载波跟踪环路采用了Costas环,以保证对180度相位翻转不敏感;码跟踪环路采用了性能良好的归一化超前减滞后码相位鉴别器,以确保对信号的准确跟踪。最后提出了窄相关技术,在噪声和多径干扰条件下能够有效降低码跟踪误差。     

Kalman滤波器在单运动目标自动跟踪中的应用

在系列帧图像中对运动目标以直方图为模型的模板方法进行匹配,由于模板匹配计算量非常大,要想在整幅图像中对目标进行搜索匹配,同时又要达到实时是不可能的。我们对目标状态进行可靠的估计,可以在相对较小的区域内完成对模板的搜索,Kalman滤波器就是一个对动态系统的状态序列进行线形最小方差估计的算法。通过以动态的状态方程和观测方程来描述系统,它可以将任意一点作为起点开始观测,采用递归滤波的方法计算。该算法具有计算量小、可实时计算的特点。     

HSRP协议在IP网络设计中的研究与应用

该文主要介绍了Cisco的HSRP(热备份路由协议)产生的历史背景及其工作原理。HSRP和MHSRP(多元热备份路由协议)能够实现路由器热备份,端口追踪,网络负载共享。网络设计工程师在设计IP网络的过程中灵活地使用HSRP和MHSRP能够设计出高可靠、高性价比的网络解决方案。     

基于连线跟踪的源地址转换技术研究与应用

面对日益严重的公用IP地址短缺问题,本文分析了共享静态IP上网和共享动态IP上网两种方式,并且针对两种共享IP上网各自所拥有的特点,研究了Linux下两种源地址转换技术,并且配合连线跟踪机制,设计了两种源地址转换方案。     

Navigation system for a smart wheelchair

Recent results on the development of a navigation system for a smart wheelchair are presented in this paper. In order to reduce the development cost, a modular solution is designed by using commercial and low cost devices. The functionalities of the tracking control system are described. Experimental results of the proposed assistive system are also presented and discussed.     

基于GPS智能测量船设计与实现

本设计采用GPS及多套数据采集系统获取数据,最终由计算机系统进行处理及控制,可对江河湖泊等区域进行无人智能化测量及监测,为改进江河湖泊等水域测量方法做了一定的探索工作。实践证明,该设计对测量研究及实际使用都有一定参考价值。     

课件录播系统的图像识别跟踪技术

本文介绍课件录播系统的图像识别跟踪技术原理,并通过与其它常用跟踪技术的比较,使大家认识图像识别跟踪技术的应用优势和在应用中的注意事项,以供选购参考。     

Reconceptualizing the School Administrator's Role: Socialization at Mid‐Career

School reform strategies involving restructuring require that administrators redefine their roles. Most of the research in this area has emphasized new rather than veteran administrators. However, if these reform strategies are to be implemented, school administrators at mid‐career stages will need to change their conceptions of the role.

This article identifies and examines literature concerning the major issues of socialization to a role conception, including definitions, sources, and socialization mechanisms for changing conceptions of the role. The article also presents a research agenda based on this theoretical examination that delineates research questions, relevant variables, and possible findings regarding changing role conceptions. The research agenda focuses on two major strategies of educational reform: shared decision making and schools of choice.     

新疆高等学校体育经费投入与场馆建设追踪研究

采用文献资料法、现场调研法、问卷调查法,对新疆高等学校体育经费的投入与体育场馆建设进行追踪研究,从而找出新疆高等学校体育场馆发展的规律与发展趋势;同时,为新疆教育职能部门的决策提供可靠信息。研究发现新疆高等学校室外体育场面积在近年的发展中提高幅度小于室内体育馆发展,体育经费投入不断增加。