基于NS2的无线网络传输性能仿真分析

探讨了IEEE 802.11 DCF的特点和NS2的结构、功能和仿真原理.通过NS2对无线网络传榆性能进行仿真测试,并提出了改善无线网络效能异常现象的有效方法.     

转型中的新建院校教学质量保障体系建设思考

教学环节是高校最基础、最本质的工作,高等教育质量的提高从本质上说是通过教学实现的,新建本科院校转型发展的过程,是其教学质量保障体系不断完善的过程,转型中的新建本科院校要提高教学质量,培养社会所需的应用型人才和创新人才,必须按照全员参与、以学生为主、以应用型人才培养为主、持续改进的原则,从提高教学质量意识、加强质量文化建设、制定科学合理质量标准、建立执行力强的运行管理体系、加强资金投入、构建有效的质量监控评价体系等方面建设和完善教学质量保障体系.     

Effects of a physical education-based coping training on adolescents’ coping skills,stress perceptions and quality of sleep

Background: Although most adolescents successfully manage the transition between childhood and adulthood, the speed and magnitude of these changes may exceed the coping abilities of a significant number of young people. For vocational students, additional responsibilities arise during the vocational school transition and the need to balance academic and job-related requirements. An expanding body of literature suggests that adolescence is a vulnerable period for the development of psychiatric diseases and as such, the need to develop an adequate coping repertoire is receiving increasing attention globally. The growing awareness of long-term consequences of stress has led governments to instill school-based resilience promotion programs. For instance, the new physical education (PE) curriculum of vocational (vocational education and training (VET)) students in Switzerland addresses stress management, because stress-related diseases at the workplace have become commonplace among young professionals.

Purpose: Our aim was to develop, implement and evaluate a PE-based coping training (EPHECT) for VET students. Therefore, we adapted components of extant field-tested coping training programs and tailored them to the unique needs of VET students. To facilitate the standardization of the program, each teacher received a teaching manual. Moreover, drawing upon experiential learning theory, we introduced the contents of the coping training in PE class through practical, movement-based exercises in PE. Students also received a workbook for use at home.

Participants and research design: In this cluster randomized controlled trial, eight classes from a Swiss vocational school participated (N?=?131, M_age?=?16.22?±?1.12, 35% females). Two trained PE teachers implemented the program with students in the intervention group (IG?=?67) for three months, while students in the other four classes maintained regular PE (CG?=?64) to comprise the control group. To evaluate the coping training, all participants completed several self-report psychological questionnaires (assessing stress, coping and sleep) at baseline and follow-up. IG students completed further questions with regard to intervention fidelity at follow-up.

Data analysis: To evaluate possible effects of the coping training on stress, coping and sleep, a 2?×?2 repeated-measures analysis of variance design was executed with time (pre vs. post) and group (IG vs. CG) as within- and between-subject factors.

Findings: Over time, IG students significantly increased their adaptive coping compared to CG students, while stress and sleep remained relatively stable for both. Regularly completing one’s homework reinforced this effect because it was significantly associated with students’ reflection and compliance.

Conclusion: A complete and accurate implementation of a PE-based coping training can make a positive contribution to the development of adaptive coping skills among adolescents attending vocational schools. This PE-based program allows students to experience their responses to stress directly and offers opportunities to experiment with different coping strategies. Adaptive coping skills are vital for successful stress management and the prevention of stress-related disorders across the work domain and in everyday life.     

谈图书馆制度建设的人本理念

建立和完善图书馆制度,是现代图书馆建设的一项重要内容。在图书馆制度中应渗透“以人为本”的理念,即“以读者为本”,“以图书馆人为本”来建立和完善图书馆有关制度,为图书馆工作的开展、科学管理的进行和服务目标的实现提供强有力的保证。     

积分中值定理注记

在本文中,我们讨论了积分中值定理的应用中应注意的一些问题,得到了几个有意义的结果。     

基于神经网络的玻璃瓶气泡和结石分类研究

研究在线视觉检测玻璃瓶气泡和结石的分类方法.根据检测系统具体的应用环境,实现了线性预分类器和BP神经网络分类器,并通过提取合理的样本特征,参数调整,整体优化了玻璃瓶气泡和结石分类识别过程,同时满足了生产的实时要求和识别的精度.     

文本检索的查询性能预测

在利用Baidu、Google等搜索引擎进行检索时,可以发现,对某些查询,搜索引擎能够准确快速地返回需要的答案,但对另一些查询,搜索引擎返回的结果却不尽如人意,需要反复修改所提交的查询.由此可以看出,查询本身的优劣和查询结果的好坏是直接相关的,如果能很好地预测查询性能,针对查询性能差的查询,有的放矢地改进检索系统,便能提高检索系统的性能了.那么,究竟什么是查询性能预测?影响查询性能的因素有哪些?怎样预测查询性能?查询性能预测的应用前景怎样?怎样评价预测查询性能方法的好坏?文章将一一回答这些问题.该文为2008年第七期本期话题<用户查询的理解>的文章之一.     

Effective learning activities in observation taks when learning to write and read argumentative texts

On repeated occasions, observational learning has proved itself to be an effective instruction method. Experimental studies have shown to be effective for complex tasks such as reading and writing for both teachers and students as models. The problem when interpreting the results of such research is that, in observation tasks, several mental activities play a simultaneous role. In this study we therefore set out to identify the effective elements of observation tasks. We focused on two elements of the observation tasks, both aimed at stimulating monitoring activities: evaluation of the model’s performance and elaboration on this evaluation. We have also distinguished between elaboration on the observed products (the models’ written answers), and elaboration on the observed processes (the models’ verbalisations of their mental activities). The data were subjected to a LISREL analysis. First of all, it was observed that subjects who performed “evaluation” and “productelaboration” better, and “process-elaboration” more often in one lesson, also performed these activities better or more often in the subsequent lesson. Next, we observed an effect of aptitude on the learning activities: pre skill scores influence “evaluation” and “product-elaboration”. The most important finding is that “evaluation” and “product-elaboration” contribute positively to argumentative writing skills. It is discussed that these findings confirm the importance of the monitoring, evaluative and reflective activities when learning complex tasks as writing.