改进LEACH算法在煤矿安全监控中的应用

提出了一种改进型LEACH算法。将能量因素加入到阈值计算公式中,均衡了节点的能耗。同时,针对重要参数难以通过实验的方式进行评估的问题,基于改进型LEACH算法建立了无线传感器煤矿安全监控网络的仿真模型,利用NS2仿真平台对其重要参数进行了仿真分析。分析结果表明,改进型LEACH算法能均衡节点的能量消耗,有效延长网络的运行时间,并且,通过仿真实现了系统模型参数的优化,验证了安全监控网络实施的可行性。     

网上学习小组特性的研究

网上小组学习是远程教育一种重要的协同学习形式,而网上学习小组的特性(如学习小组的组织结构、组员对小组活动促进学习的认识、情感因素,以及对教师的期待等)会影响到活动的效果。但目前国内外有关网上学习小组的实证研究较为鲜见。本研究通过教学试验、问卷调查和书面访谈后发现,成功的学习小组规模要适中,组员的水平、志趣、背景等有一定差异,对网上小组活动在学习上的促进作用认同程度高,能处理好协作与自主、认知与情感、个人成就与集体荣誉等关系,形成一个平等、互动、宽松、愉悦的虚拟学习社区。同时,教师从学习活动的设计、组织到整个过程都要“积极干预”,既解疑释惑、传授知识又培养正确的学习技巧,同时,也要体现人文关怀,肯定成绩,指出不足,营造学习氛围,鼓励大胆创新。     

远程教育研究的"中"与"外"

经过"本土实践"验证的理论才真正具有中国特色,扎根于"本土"的理论才能在国际视野中占有一席之地.     

High cycle fatigue life prediction and reliability analysis of aeroengine blades

Based on the nonlinear continuum damage model(CDM) developed by Chaboche,a modified model for high cycle fatigue of TC4 alloy was proposed.Unsymmetrical cycle fatigue tests were conducted on rod specimens at room temperature.Then the material parameters needed in the CDM were obtained by the fatigue tests,and the stress distribution of the specimen was calculated by FE method.Compared with the linear damage model(LDM),the damage results and the life prediction of the CDM show a better agreement with the test and they are more precise than the LDM.By applying the CDM developed in this study to the life prediction of aeroengine blades,it is concluded that the root is the most dangerous region of the whole blade and the shortest life is 58 211 cycles.Finally,the Cox proportional hazard model of survival analysis was applied to the analysis of the fatigue reliability.The Cox model takes the covariates into consideration,which include diameter,weight,mean stress and tensile strength.The result shows that the mean stress is the only factor that accelerates the fracture process.     

Tutors’ influence on distance language students’ learning motivation: voices from learners and tutors

Teachers’ influence on students’ learning motivation is a well-researched topic. Nevertheless, the majority of such studies are situated in the conventional learning context despite the rapid growth of distance language learning. This study set out to investigate tutors’ influence on students’ learning motivation in the Chinese distance language learning context. It attempted to gain a balanced picture of the issue under study by taking both student and tutor views into account. Findings from this study indicate that teaching competence, personal characteristics, subject matter expertise, and tutor–student relationship were four tutor-related factors which affected students’ learning motivation, reinforcing results of previous studies. Nevertheless, mismatches were found between students and tutors in relation to the influence of particular aspects of teaching competence, personal characteristics, and subject matter expertise. Implications from the study are considered in this article.     

一代名士潘岳的人文情怀论析

对西晋文人潘岳的评价,向来褒贬不一。说其作品“失真”的有之,说其是西晋形式主义诗风的代表的也有之。笔者认为,诗歌作为一种精神产品,其特质往往由创作者的特征决定。本文从潘岳的诗歌入手,透过历史的重重烟雾,探析诗人内心深处最真实的表露,还原一个宽容、仁慈、孝顺、珍惜生命、热爱生活的潘岳,从而肯定其历史价值。     

What do distance language tutors say about teacher motivation?

Research into motivation in education mainly centres on students’ learning motivation. This article reports on an interview study of teacher motivation with the aim of investigating the effects of student-related factors and tutors’ personal factors on the motivation of language tutors in the distance learning context. Findings from the study indicate that external sources of influence include students’ engagement in learning English, motivation to learn English, progress made, foundation in English and appreciation of tutors’ teaching, while tutors’ internal factors are their self-efficacy in teaching, reflection and self-initiated professional development, interest in the profession of teaching English as well as their sense of achievement. Analysis of the data also suggests that more concrete measures are needed to counteract the demotivating effects from these two dimensions. Implications and suggestions are discussed with regard to enhancing tutor motivation more effectively.     

PCSI:一种单篇论文被引频次标准化方法

[目的/意义]文章的被引频次一直是量化评价一篇论文学术影响力的重要指标。但在不同学科不同年份发表的论文会因该领域研究论文数、引用滞后等因素呈现较大的差异。因此在对比两篇论文时,难以简单依据被引频次的绝对值来评判论文影响力大小。为此,本文设计了一个新的可计算数学模型,使得每篇论文可以有一个标准化的指标,以便对不同学科不同年份发表的论文的学术影响力进行直接比较。[方法/过程]通过分析2006、2017两年中国科技类学术期刊各学科论文的被引频次分布规律,采用同学科论文被引频次的分布形态最接近对数正态分布的先设条件,提出一种被引频次标准化指数——Paper Citation Standardized Index (简称PCSI,中文"论文引证标准化指数")。最后以中国科协优秀科技期刊论文评选结果为例,将它们与论文所属学科全部论文进行实证对比研究。[结果/结论]结果证明,PCSI对不同年份、不同学科论文的被引频次进行了标准化,反映了被引频次的线性差距,是一种较为理想的单篇论文学术影响力比较评价工具。     

生态远程教育——从生态语言学的启示谈起

也许正是为了保持远程教育的“生态平衡”,混合学习正引起越来越多的注意。对于生态语言学一直有所闻,最近读了《国际应用语言学协会评论专刊:面向21世纪的应用语言学》(第14期)上一位奥地利应用语言学家Alwin Fill撰写的一篇文章,觉得生态语言学的原理对于现代远程教育有所启示,遂把杂感记录下来,抛砖引玉。生态语言学以语言与生态之间的关系为研究对象,涉及诸多方面内容,我想就从其主要的研究目标之一——语言的多样性——作为切入点,反思对发展远程教育的启发。工业化的经济和全球一体化进程的推进导致了经济强国的语言更加突显而欠发达…     

初中生物学教学生活化——以人教版初中生物学七年级上册为例

DU Junhong;HAN Ning;WANG Zhongli(College of Life Science, Yunnan Normal University, Kunming, Yunnan 650500)