美国的州立图书馆及其作用——美国图书馆的管理和运营概述之一

文章介绍了美国州立图书馆在美国图书馆系统中的作用和在美国图书馆发展中,在执行美国有关图书馆法的过程作所起的作用。通过对州图书馆发展的历史回顾,州图书馆在州政府的行政隶属关系,以及美国法律中对州图书馆职能的规定等方面的讨论,可以看出州图书馆及其作用的形成有其历史、政治和法律的原因。在此基础上,文章进一步讨论州图书馆对公众,州内各级政府以及各类图书馆所提供的服务。最后介绍州图书馆按《美国图书馆服务和技术法案》规定,在执行联邦政府图书馆法和监管政府图书馆基金时必须进行的图书馆服务计划的制定和评估过程。     

Independent force and position control for cooperating manipulators

The problem of independent force and position control of multitask cooperating manipulators is studied. Each manipulator is in a non-singular configuration and the object can be driven by the contact forces exerted by the end effectors of the manipulators. The design requirement is to control each coordinate of the position of the object as well as each component of the “rest” forces, except the moving forces that are determined uniquely from the object's position. The present design requirement has been proved to be always satisfied together with asymptotic and BIBO stability. A class of controllers solving the above simultaneous problem is analytically determined. The proposed state feedback controller does not depend upon the specific object dynamics and thus the resulting closed-loop multimanipulator system performs as required, not only when handling various objects but also when the dynamics of the objects are unknown or hard to compute or disturbed by external forces.     

Approaches for Effective Vocationalisation of Secondary School Agriculture in Nigeria: The Views of Agricultural Science Teachers in Delta State,Nigeria

Abstract

This paper describes a random sample of serving agricultural science teachers in Delta State, Nigeria, as a background to understanding their views on four selected approaches for effective vocationalisation of secondary school agriculture. These approaches were used to develop a 23-item questionnaire based on current literature. A five-point Likert-type scale was used to determine how well the views of the respondents corresponded with the items in the questionnaire. Results showed, among others, that the average teaching experience of the 322 sampled teachers was 12.9 years; 50.6 % of the respondents were BSc(Ed) degree holders; 38.8% had Nigerian Certificate in Education (NCE), while 10.6% were Higher National Diploma (HND) holders. The respondents agreed that the identified approaches were necessary for effective vocationalisation of secondary school agriculture. The paper therefore recommends that the identified approaches should be pursued by the Nigerian government to ensure that vocational agriculture in secondary schools achieves the goals of the National Policy on Education.     

虚拟学习社区中学生学习行为的实证研究

用数据挖掘技术自动分析学生行为的兴趣差异爱好,研究结果表明：场独立型学生频繁使用后退、前进按钮,在导航面板上花费的时间较少。场依赖型学生经常使用主菜单和对学习内容进行重复访问。     

Evaluation of change blindness in multimedia learning environment with cognitive process

ABSTRACT

This study aims to investigate the change blindness and cognitive processes with eye-tracking method in multimedia learning environment. For this purpose, a multimedia animation which had some changes was designed. The eye movements were examined during the process of detecting the changes in multimedia via eye-tracking technics. The research model was defined as controlled experiment and survey methods. Twenty-one ungraduated students participated in the experiment. Attention and perception levels of participants were determined by d2 Attention Test and Group Embedded Figures Test. Change detection numbers of participants were analyzed according to their attention level and field dependence. The appearance of a major object on the scene was the most detected change and the change on the detail object was detected less. According to findings about the attention level and change detection, the participants at high attention level were more successful at detecting change in multimedia. It was observed that field-independent individuals could detect the change much more compared to the field-dependent individuals.     

村民自治制度运行中的路径依赖问题分析

村民委员会自治制度是与我国依法治国战略的实施和市场经济体制的改革相适应的农村基层管理制度。村民自治制度30多年的实践已经取得了一些成效,在农村基层民主政治建设方面有了新的发展。但在该制度的现实运行中,原有制度惯性的影响是村民自治制度健康持续发展中一个不容忽视的问题。     

《六安州志》描绘的文学地图

同治年间修撰的《六安州志》保存了一批古代六安州的珍贵文学资料,这些资料描绘出六安州I文学写作地图的轮廓,具有潜在的文学史意义,即它以原生态、隐性书写形式,描绘了文学史多层架构的空间图谱。     

曹魏行政体制中的州郡

曹魏时期三级行政体制似仍在发展之中,州作为高层政区似并不完整,中央仍对郡国实行直接控制,而且民政重心仍在郡国。     

东周齐国封建官僚体制的形成过程

春秋早期的齐国继承了西周的乡遂制度,推行“三国五鄙制”。战国初期齐国县的职能有所增加,基层行政单位的里管理加强。但乡、州、里的上下统属关系还没有变,都作为县的上级行政机构还没有产生。战国中后期,都的下级行政组织州、县、乡、里上下统属关系确立,齐国封建政体最终形成。     

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.