Linear output-feedback-based semi-global stabilization for switched nonlinear time-delay systems

This paper focuses on the problem of semi-global output-feedback stabilization for a class of switched nonlinear time-delay systems in strict-feedback form. A switched state observer is first constructed, then switched linear output-feedback controllers for individual subsystems are designed. By skillfully constructing multiple Lyapunov–Krasovskii functionals and successfully solving several troublesome obstacles, such as time-varying delay and switching signals and nonlinearity in the design procedure, the switched linear output-feedback controllers designed can render the resulting closed-loop switched system semi-globally stabilizable under a class of switching signals with average dwell time. Furthermore, under some milder conditions on nonlinearities, the semi-global output-feedback stabilization problem for switched nonlinear time-delay systems is also studied. Simulation studies on two examples, which include a continuous stirred tank reactor, are carried out to demonstrate the effectiveness of the proposed approach.     

Family socioeconomic status,parental expectations,and adolescents’ academic achievements: a case of China

This study examines direct and indirect effects of family socioeconomic status (SES) and parental expectations on adolescents’ mathematics and problem-solving achievement in mainland China. SES here is composed of family wealth, home educational resources, and parental education. Over 5,000 ninth-grade students in 5 geographical districts of China participated in the study and were assessed by using the items adapted from the Programme for International Student Assessment (PISA). Results from structural equation modelling indicated that 2 components of SES – home educational resources and parental education – positively predicted parental expectations; however, the 3rd component – family wealth – negatively predicted parental expectations. Family wealth, parental education, and parental expectations significantly predicted mathematics achievement, and home educational resources, parental education, and parental expectations significantly predicted problem-solving achievement. The 3 components of SES also had significant indirect effects on both mathematics and problem-solving achievement through parental expectations, and the effect of family wealth was a suppression effect. These results were further discussed from Chinese cultural contexts.     

论程序正义与和谐社会构建的内在逻辑

从逻辑角度而言,程序正义与和谐社会构建存在非常紧密的联系：程序正义具有合理分配利益的功能,这是和谐社会构建的基础;程序正义具有保障公民权利的功能,这是和谐社会构建的重要条件;程序正义具有防范国家权力滥用功能,这是和谐社会构建的内在要求;程序正义具有和平解决冲突的功能,这是和谐社会构建的重要标尺;程序正义有助于世界各国的联系和交往,这是和谐社会构建全球化必然趋势。     

STC单片机在选矿给料控制系统中的应用

设计了一种基于STC12C5A32S2单片机的选矿给料控制系统。该系统采用PWM/DC转换技术对变频器进行频率设定(0～120Hz),进而控制选矿给料系统的给料量,并以较少的按键实现了参数设置,同时运用单片机内部自带的A/D把核子秤测量的给料量大小(4～20mA的电流信号)进行实时显示。系统具有可靠性高、易于操作等特点。     

大学考试试题质量的量化研究

考试试题质量是指测验人员所选样本对测试对象属性的测量程度,具体表现为教师编制试题的难易度、信效度以及区分度。本研究随机抽取河西学院2007-2008学年第二学期8个系的16门考试课程为研究样本,对考试结果进行统计分析。结果表明:(1)期末成绩和总评成绩分布大部分呈正态分布,部分考试成绩分布呈现出不对称和尖峰态;(2)期末考试成绩等级上,理科在优秀和良好的比例高于文科在同一等级上的比例,同时,理科在不及格上的比例高于文科。总评考试成绩等级上,理科在优秀和良好的比例高于文科在同一等级上的比例,但是,理科在不及格等级上的比例低于文科,反映出平时成绩对总评成绩的随意性影响;(3)期末试题的难度系数高,试题难度较小,并且文理科和难度系数等级之间的卡方检验无显著的统计学意义;(4)期末试题区分度偏低,并且文理科和区分度系数等级之间的卡方检验无显著的统计学意义。     

Enhancing children's literacy skills: designing the Q‐Tales ecosystem for children's e‐book design and publication

This article describes the conceptualisation and development of a pedagogical framework to support the design of e‐books for children to enhance literacy development. It emerged from research undertaken within the Q‐Tales international consortium project of the EU's Horizon 2020 Programme for Research and Innovation, where the aim was to facilitate key stakeholders to collaborate and participate in the online production and publication of high‐quality, educational e‐books for children. The pedagogical framework described here sought to answer the question “What concepts and principles undergird the effective design of pedagogically impactful e‐books for children?” It is grounded by the theoretical underpinnings of socio‐constructivism, constructionism and skill theory, and how they relate to children's literacy development. A framework describing different narrative forms and component features, key pedagogical activities appropriate for different stages of reading development and design recommendations regarding the integration of multimedia into e‐books are also central to the pedagogical framework. As well as informing the design of the Q‐Tales infrastructure for children's e‐book design and publication, we hope the guidelines and pedagogical activities enumerated here will be widely useful for those designing and developing digital, interactive narratives, particularly e‐books to enhance children's emerging literacy.     

高效课堂技术化模型的内在关联及平衡点

先进理念与有力技术的完美结合是缔造现代课堂典范形态的两大支撑点。当代高效课堂改革的内在线路之一是寻求一条高效课堂理念与现代技术文化之间更为完美的结合方式。技术是＂形而上＂的思想与＂形而下＂的工具组成的有机体,高效课堂理念在技术文化的技术思维、技术手段、技术工艺等层面都能找到相应的结合点。高效课堂理念技术化过程的实质是先进课改理念与技术文化全面融合的立体化过程,是先进课改理念借技术思维、技术手段、技术工艺来付诸实践的过程。这一过程有三个关键环节：课改理念的精确化、课堂手段的现代化与教学过程的工艺化,构成了高效课改理念技术化的＂三部曲＂。如何在技术与艺术之间寻求一种平衡,努力实现理念与实践在技术条件中的完美耦合与整合匹配,是当代高效课堂改革的重要思路。这一平衡的实现需要重点解决三大平衡：有形模式与无形变革间的平衡、理念创新与技术配合间的平衡、学习环境与教学控制间的平衡。     

群众与政府角色错位对民族关系的影响——对“切糕门”事件的反思

在民族交往之中,经济交往是一个重要方面.2012年在岳阳因买卖切糕发生的“切糕门”事件让人印象深刻.在此过程中,社会大众扮演政府的角色对此进行了多方面的讨论,其中有些讨论放大了民族成员之间纠纷,同时也对民族成员之间关系产生了正反两方面的影响.就“切糕门”事件进行反思,流入地政府管理对少数民族流动人口管理力度不够只是表面促因,而民族之间的经济、文化差异则是深层促因.面对人口流动越来越频繁所来带的挑战,相关政府部门应深入分析造成民族纠纷事件的深层原因,加强对少数民族流动人口的管理,引导他们合法合理经营,协调其经营中的问题,以积极态度化解矛盾,避免纠纷的产生.     

ACADEMIC PERFORMANCE,ATTITUDES, AND SOCIAL RELATIONS IN INTERGENERATIONAL COLLEGE CLASSES

Increasing acceptance of the idea of older adults returning to college campuses has raised a number of questions. Not least among the concerns are those related to classroom behavior and classroom relations. Despite the philosophical support for mixing older and younger students in college classes, limited empirical support is available to administrators who must contend with the fears of younger students and the insecurity of faculty. Therefore, this study was designed to analyze research concerning three important dimensions of the mixed classroom: academic performance, attitudes, and social relations.

Studies reported in three major gerontological journals since 1978 were reviewed. Accordingly, seven studies reported in 1980 or later were identified and analyzed. Based on the analysis, conclusions and recommendations are reported.     

我国高校中外合作办学模式探讨

中外合作办学不但直接引进了境外优质教育资源,而且能提高对高等教育国际化的必然性与重要性的认识,确定国际化人才的培养目标。通过合作办学,将会促进人员交流、课程设置、科学研究、管理机制的国际化。本文通过对我国中外合作办学进程的回顾,对目前我国高校与国外合作办学模式进行梳理,并以中国地质大学（北京）为例,提出几个合作办学的新形式,供其他开展中外合作办学的高校参考。