自适应学习系统中双向适应交互评价实证研究

随着信息技术的快速发展,网络学习已经成为人们生活中不可或缺的一种学习方式。以实现网络个性化学习为目标的自适应学习系统成为提高网络学习质量的重要研究课题。然而目前大多数自适应学习系统仅具有单向适应能力,即实现了系统根据用户特性适应性向学习者呈现学习资源、过程和策略的功能。尽管这种功能有助于解决学习者认知超载和网络迷航问题,一定程度上提高了学习效率,但学习者在此系统中是一种被动学习,不利于培养学习者自主学习能力和创新能力,也不利于促进学习者对知识的主动建构,还容易使学习者产生惰性。因此,应该充分考虑学习者和系统之间的主客体关系,在自适应学习系统中建立双向适应交互,即用户主动选择资源的适应性交互和系统主动推送资源的自适应交互。双向适应交互最为关键的是用户模型,而认知风格是用户模型中影响学习者个体差异的一个重要元素。从学习效率和使用感受两个层面实证评价双向适应交互性,以及认知风格对其的影响发现:采用自适应学习方式,学习者具有更积极的学习态度,能够取得更好的学习绩效;但认知风格会影响到自适应学习和适应性学习的绩效。     

Relational maintenance and caregiving in the grandparent-grandchild relationship

ABSTRACT

The purpose of this study was to examine the relationships between grandparents’ use of relational maintenance behaviors (RMB) and their young adult grandchildren’s willingness to serve as future caregivers for their grandparents. Undergraduate students (N = 209) completed a questionnaire in which they reported on a specific grandparent’s use of RMB and how willing they were to serve as future caregivers for that specific grandparent. Results of a multiple regression analysis provided partial support for the hypothesized positive relationships between grandparents’ use of RMB and grandchildren’s willingness to serve as future caregivers for their grandparents.     

危险的民主--美国全球民主战略和"大中东"

美国外交战略的主要目标是领导世界、维护其霸权地位。美国以武力或“柔性”施压在中东地区推行美国式的民主而使得民主失去了原有意义,变成“危险的民主”。“适应型民主”对美国与阿拉伯世界都提出了要求,它的实施对中东的民主化进程与世界的和平与安全将是行之有效的。     

Three-dimensional tracking of GLUT4 vesicles in TIRF microscopy

TIRF microscopy has provided a means to view mobile granules within 100 nm in size in two dimensions. However quantitative analysis of the position and motion of those granules requires an appropriate tracking method. In this paper, we present a new tracking algorithm combined with the unique features of TIRF. Firstly a fluorescence correction procedure was processed to solve the problem of fluorescence bleaching over time. Mobile granules were then segmented from a time-lapse image stack by an adaptive background subtraction method. Kalman filter was introduced to estimate and track the granules that allowed reducing searching range and hence greater reliability in tracking process. After the tracked granules were located in x-y plane, the z-position was indirectly inferred from the changes in their intensities. In the experiments the algorithm was applied in tracking GLUT4 vesicles in living adipose cells. The results indicate that the algorithm has achieved robust estimation and tracking of the vesicles in three dimensions.     

网络环境下有效学习行为特征及影响因素研究

在网络环境下,学习者由于高度自由同时又缺乏有效的监管,学习很容易受到外界事件的干扰,并不能完全保证学习者的学习行为是有效的。为保证网络环境下学习的质量与绩效,有必要对网络环境下的有效学习行为进行深入研究。文章在“有效学习”定义基础上,提出网络环境下有效学习行为的概念及其特征,并详细讨论了网络环境下有效学习行为的主要影响因素,最后从中得到提高网络环境下学习行为有效性的启示:在课前,教师要做好学前分析,检查学习者是否已有本次学习必要的基础知识储备,并帮助学习者明确自己的学习目标,给学习者提供必要的学习环境;在课中,教师要注重学习者信息技术应用能力的培养,同时给学习者施加一定的外部动机,并结合具体情况,给予学习者有效的引导;在课后,教师需要及时对这节课进行反思总结。     

噪声主动控制的进展及发展趋势

对噪声主动控制技术领域的进展及发展趋势进行综述.包括消声原理、消声器结构和算法等方面的研究成果,分析该技术存在的缺陷,对今后的主要发展方向作出预测.     

Actuator fault diagnosis for a class of bilinear systems with uncertainty

In this paper, the actuator fault diagnosis problem for a class of bilinear systems with uncertainty is discussed. The system is transformed into two different subsystems. One is not affected by actuator fault, so an adaptive observer can be designed such that, under certain conditions, the observer error dynamics is stable. The other whose states can be measured is affected by the faults. The observation scheme is then used for model-based fault diagnosis. Finally, an example of a semiactive suspension system is used to illustrate the applicability of the proposed method.     

微博社区成员参与的心理影响因素实证分析

利用逐步多元回归分析法,探明并实证分析了微博社区成员参与行为的心理影响因素。研究发现,成员的自我呈现、感知方便性和感知可信性对他们的参与行为存在显著影响。并且,自我认同和社会强化能显著地影响成员投入到微博社区中的努力。理论层面上,研究结论为下一步参与行为的心理作用路径研究和群体心理与行为研究提供前提;实践层面上,对微博服务提供者经营和管理微博社区以及政府相关部门管理微博具有现实意义。     

From scraps to reams to mobile screens? An update on printing services in academic libraries

As a follow-up to their 2001/2002 study on printing services in academic libraries, the authors explore how the provision of printing services has changed over the last twelve years. This article explores how libraries are choosing to fund printing services as well as how technology, such as scanning and mobile devices, has changed the way printing services are provided. The results of the 2013 survey find a greater percentage of libraries are using a fee-based system for printing, and, while some technology is providing greater data and control for printing services, other technological advances are having unintended consequences for libraries’ printing infrastructure.     

自然美的衰退与人的审美行为的成熟

随着现代文明的发展,人们对自然的审美行为愈益成熟,即对自然进行审美时运用太多的分析技巧,合理化意识支配着他;这足以导致自然美的衰退。要想使自然美有更多的呈现就必须恢复审美行为的单纯性,借助情感、联想、想象同自然进行富有生气的沟通,并对自然有一种描写与抒情的欲望。在当代生态环境面临恶化的条件下,这种面对自然的单纯性的审美行为具有积极的意义。