活动理论视域下远程学习目标结构之建构冰     

曹东云  杨南昌 《现代远程教育研究》2013,(2):25-30

当前远程学习的课程设计普遍存在目标设计缺失的现象,这可能源于人们对远程学习目标“是何”及“如何”运作的认识不够,从而导致学习者面临学习失败的风险。探讨远程学习目标“是何”是研究“如何”的先决条件。远程学习目标结构研究,旨在探讨远程学习目标的类别及其关系。活动理论是一种重在把活动系统作为分析单位的分析模式,迄今为止经历了“中介说”、“层次说”、“要素说”三代发展历程,为人们重新认识远程学习的目标结构提供了新的视角。它提示人们可以从活动层中的“过程”与“结果”维度去认识远程学习的目标结构,并从行动层中提取描述远程学习过程目标的5个要素：主体、客体、工具、行为、时间,建构出远程学习“过程一结果”目标结构的分析框架。远程学习目标结构可以帮助学习者在学习之初对远程学习结果及实现结果的过程做出规划,为之后的目标实施及评价提供保障,规避学习失败的风险。  相似文献   

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

Zhenhua Li  Lijun Long  Jun Zhao 《Journal of The Franklin Institute》2019,356(13):7224-7245

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.  相似文献   

Output regulation for a class of positive switched systems     

Peng Wang  Dan Ma  Jun Zhao 《Journal of The Franklin Institute》2019,356(8):4513-4529

In this paper, a complete procedure for the study of the output regulation problem is established for a class of positive switched systems utilizing a multiple linear copositive Lyapunov functions scheme. The feature of the developed approach is that each subsystem is not required to has a solution to the problem. Moreover, two types of controllers and switching laws are devised. The first one depends on the state together with the external input and the other depends only the error. The conditions ensuring the solvability of the problem for positive switched systems are presented in the form of linear matrix equations plus linear inequalities under some mild constraints. Two examples are finally given to show the performance of the proposed control strategy.  相似文献   

跨域环境治理的多元主体共建共享机制     

褚义景  .戴胜利 《科技管理研究》2019,(21)

跨域环境治理领域内的多元主体共建共享机制能否以及如何构建是一个备受关注的话题。文章在审视跨域环境治理特性的基础上,回答了为什么要构建多元主体共建共享机制的问题;根据过程分析理论的有关结论,解析跨域环境治理的流程与环节,回应了如何构建多元主体共建共享机制的问题。文章认为,通过多元主体共建共享机制的设计,达成政府、市场、社会团体和公众在内的多元主体合作共治,是实现区域环境公共利益最大化的重要途径。  相似文献   

Understanding the topic evolution of scientific literatures like an evolving city: Using Google Word2Vec model and spatial autocorrelation analysis     

Kai Hu  Qing Luo  Kunlun Qi  Siluo Yang  Jin Mao  Xiaokang Fu  Jie Zheng  Huayi Wu  Ya Guo  Qibing Zhu 《Information processing & management》2019,56(4):1185-1203

Topic evolution has been described by many approaches from a macro level to a detail level, by extracting topic dynamics from text in literature and other media types. However, why the evolution happens is less studied. In this paper, we focus on whether and how the keyword semantics can invoke or affect the topic evolution. We assume that the semantic relatedness among the keywords can affect topic popularity during literature surveying and citing process, thus invoking evolution. However, the assumption is needed to be confirmed in an approach that fully considers the semantic interactions among topics. Traditional topic evolution analyses in scientometric domains cannot provide such support because of using limited semantic meanings. To address this problem, we apply the Google Word2Vec, a deep learning language model, to enhance the keywords with more complete semantic information. We further develop the semantic space as an urban geographic space. We analyze the topic evolution geographically using the measures of spatial autocorrelation, as if keywords are the changing lands in an evolving city. The keyword citations (keyword citation counts one when the paper containing this keyword obtains a citation) are used as an indicator of keyword popularity. Using the bibliographical datasets of the geographical natural hazard field, experimental results demonstrate that in some local areas, the popularity of keywords is affecting that of the surrounding keywords. However, there are no significant impacts on the evolution of all keywords. The spatial autocorrelation analysis identifies the interaction patterns (including High-High leading, High-Low suppressing) among the keywords in local areas. This approach can be regarded as an analyzing framework borrowed from geospatial modeling. Moreover, the prediction results in local areas are demonstrated to be more accurate if considering the spatial autocorrelations.  相似文献   

图书馆精神与英美民主化进程的历史渊源   总被引：1，自引：0，他引：1  

李静 《当代图书馆》2008,(1):23-26

公共图书馆精神源于英美民主政治文化传统。民主政治及其所蕴含的人文精神是图书馆精神形成的必备条件。我国图书馆精神必将依赖我国政治文化的改善加快进程。  相似文献   

根据CMM实施软件过程改进   总被引：1，自引：0，他引：1  

陈晴 《闽江学院学报》2004,25(5):81-83

软件过程控制是影响软件产品质量的关键要素之一。在软件过程中要借助有效的工具实施CMM，实现软件过程的改进。在实施过程中要遵循自低向上、循序渐进、测试先行的策略。  相似文献   

HPT项目管理:绩效技术人员的工具与技术——对绩效技术项目过程模型的修正与重构整合     

于文浩  徐丹 《现代教育技术》2008,18(4):26-30

绩效技术作为教育技术的拓展,极大的拓宽了教育技术的实践领域。文章论述了绩效技术中的项目管理和项目管理的生命周期,并对权威的绩效技术项目的过程模型进行了修正和重构。在论述了项目的三重约束理论后,文章尝试着创造性的提出了绩效技术的项目管理的整合模型。  相似文献   

TPR And TPR Activities     

宋丽萍 《时代教育》2008,(7)

This paper presents the definition of Total Physical Response(TPR),elaborates the process and the principles of it 80 that more and more TPR activities can be created according to them.The use of TPR shows us an interesting and effective way of teaching and learning English.TPR activities are interesting,challenging and motivating that almost all the students enjoy them.  相似文献   

隧洞爆破方案优化的层次分析     

闫爱军  雷静 《杨凌职业技术学院学报》2008,7(2):5-7

针对隧洞爆破总成本的最优化这个实际问题,重点分析影响隧洞爆破工程总成本的四项因素：钻孔成本、爆破成本、装载成本和运输成本的情况下,结合一个工程实例,采用层次分析的方法进行了分析论证,提出了相应的优化方案,可为合理探求隧洞爆破总成本的最优化和目前工程建设单位需要解决成本最优化问题提供一定的借鉴作用。  相似文献