一类二维对流扩散方程的有限元法

利用有限元法求解了二维对流扩散方程边值问题,得到了相应的误差分析,并进行了数值模拟。模拟结果表明该方法求得的数值解有较高的精度和较快的运行速度。     

随机误差的Matlab处理方法研究

测量过程中不可避免存在着随机误差,当测量次数n增大时,用手工处理随机误差不仅过程复杂,计算量大,可靠性也不高。本文讨论了借助Matlab强大的数据处理功能处理随机误差,使处理过程简单快速。     

快速汉克尔变换算法的误差修正

比较详细地分析了快速汉克尔变换误差原因,给出修正方案,有效地提高了算法精度。     

稳态Stokes问题的最大模估计

考察了二维稳态Ｓｔｏｋｅｓ问题的基于速度－压力形式的非协调Ｃ－Ｒ有限元逼近,利用Ｓｏｂｏｌｅｖ权模技巧和权模ＬＢＢ条件,得到了稳态Ｓｔｏｋｅｓ问题速度和压力逼近解的拟最优的最大模估计。     

一类偏微分方程特征值的带权估计

考虑一类偏微分方程特征值的带权估计,利用分部积分、Rayleigh定理和不等式估计等方法,获得了用前n个特征值来估计第N＋1个特征值的上界的不等式,其估计系数与区域的度量无关,这个结果在力学和物理学中有着广泛的应用。     

一个修正的三阶收敛的牛顿迭代法

给出了牛顿迭代法的一种修正形式,证明了它是三阶收敛的,通过数值算例进行了验证.     

高校扩招使得个体就业状况更糟糕吗?

基于高校扩招前后大学生群体的比较,人们普遍认为扩招后大学生的就业状况变差了。我们在认同这一观点的基础上,着重考察了另外一个问题:在教育扩张的背景下,如果个体读大学与假设他不读大学相比,就业状况会如何?利用扩招前后两个年份的全国性人口调查数据,采用描述性统计和基于倾向分匹配估计的方法对此进行了分析。主要结论是:高校扩招后大学毕业生相对于高中毕业生在就业上仍旧延续了优势地位,并且没有明显的变化,现实中观察到的扩招后大学生失业率的上升更多的是由于个体能力和家庭背景等因素造成的,高校扩招在其中仅起到微弱的作用。其政策含义是,就业政策应更加关注低学历人群的就业和就业保障,我国初中后教育规模的进一步扩张仍具有现实基础。     

Affective-motivational effects of performance feedback in computer-based assessment: Does error message complexity matter?

The impact of computer-based performance feedback on students’ affective-motivational state may be very different, depending on the positive or negative direction of the feedback message and its specific content. This experiment investigated whether more elaborated error messages improve students’ affective-motivational response to negative (i.e., corrective) feedback. We systematically varied the presence and complexity of corrective feedback messages (1 × 4 between-subjects design) and analyzed the effects of the provided feedback on students’ emotions, task-related perceived usefulness, and expectancy-value beliefs. University students (N = 439) worked on a low-stakes test with 12 constructed-response geometry tasks. They received either no feedback or different complexities of immediate corrective feedback after incorrect responses (i.e., Knowledge of Results [KR], Knowledge of Correct Response [KCR], or Elaborated Feedback [EF]), paired with immediate confirmatory KCR feedback after correct responses (i.e., confirming their response). Our data showed that students’ task-level performance moderated the emotional impact of feedback (i.e., beneficial effects after correct responses; detrimental effects after incorrect responses). Students’ performance further moderated several feedback effects on students’ expectancy-value beliefs. Regarding error message complexity, we found that students reported higher levels of positive emotions after receiving EF or KCR compared to KR, while only EF decreased students' level of negative emotions compared to KR and increased students' task-related perceived usefulness compared to all other groups. Overall, our results suggest that performance feedback is likely to improve students’ affective-motivational state when the feedback confirms a correct response. Moreover, when reporting an error, EF (or KCR messages) were more beneficial to affective-motivational outcomes than simple KR notifications.     

错误分析法在英语写作教学中的应用

英文写作能反映学生综合应用语言的能力。学生作文中经常出现各种错误。本文根据Corder的错误分析理论对英语专科学生作文中的错误进行分析,找出原因,并就此给出合理建议和启示。     

卷积码UEP方案在分等级传输中的应用

讨论了卷积码及删截卷积码的编、译码原理，通过仿真分析了由二者构造的不等差错保护系统的性能和特点，仿真结果表明，该UEP方案在分等级传输中能获得较好的性能。