具有n重特征根的一类n阶常系数非齐次线性微分方程的变量代换解法

该篇证明了一个定理,给出了具有ｎ重特征根的一类ｎ阶常系数非齐次线性微分方程求其特解的一种变量代换解法,并具体给出了解的形式     

Until when does the effect of age on academic achievement persist? Evidence from Korean data

According to an analysis of Korean student panel survey data, monthly differences in age had a significant influence on academic achievement until middle school (lower secondary education). However, this age effect did not persist when students graduated from high school (upper secondary education). Furthermore, some evidence is found that younger students, upon entering high school, were more likely to concentrate on academic studies, and less likely to experience minor distractions, thereby compensating for their poor academic achievement in middle school.     

变化风场中无人机稳定控制系统的设计与仿真

针对变化风场尤其是大气紊流严重影响无人机飞行安全的问题,通过构建大气紊流数学模型并分析其对飞行的影响,为非线性无人机建立了六自由度模型,设计了一种模糊自整定PID控制器并进行了Matlab仿真。仿真结果表明,该控制器可提高无人机在变化风场中的稳定性和稳态精度。     

Building collaborative structures for teachers’ autonomy and self-efficacy: the mediating role of participative management and learning culture

This study focused on the collaborative structure-building behavior of school principals and examined how such behavior affects teacher empowerment. More important, it tested the mediating effects of participative management and learning culture. By collecting nested data from 104 schools in Hong Kong and adopting multilevel structural equation modeling, we found that teachers’ sense of autonomy and self-efficacy were correlated at the individual level but were independent at the school level. The effect of building collaborative structures on teachers’ self-efficacy was mediated by both participative management and learning culture, whereas the effect on autonomy was mediated by participative management only. The findings contribute to the literature in at least 2 ways. First, the inclusion of both principal leadership and school-level factors provides more refined predications of teacher empowerment. Second, the testing of the theory-grounded hypotheses in an Asian society verifies the validity of certain cultural assertions about this region.     

概率方法证明组合恒等式

概率方法证明组合恒等式的思想是运用完备事件组、全概率公式、随机变量的数字特征来证明恒等式,以及古典概型在排列组合恒等式证明中的应用.进而来说明利用概率方法证明组合恒等式的优点。     

数据结构线性探测法在随机出题中的应用

以数据结构散列查找中的线性探测法入手,分析了线性探测法的基本原理,算法描述及查找性能.结合线性探测法在随机出题中的应用设计了抽取试题的算法.从整体思路,算法设计,运行分析三方面剖析了该算法的实现过程及效率.     

单摆测重力加速度的比较研究

用单摆测重力加速是中学物理较重要的实验,本文应用传统方法、计时器、传感器三种测量方式对重力加速度进行测量。三种测量方法均在误差范围内,结果发现利用传感器测量结果误差最小。     

脉动式CVT连杆机构的运动规律研究

本文对曲柄摇块式脉动无级变速的传动机构进行了运动分析,从运动学原理对机构进行深入研究,得出该机构的最佳参数,减小脉动及动载荷,降低功率损耗,进而改善其运动及动力性能,     

Accelerated matrix recovery via random projection based on inexact augmented Lagrange multiplier method

In this paper, a unified matrix recovery model was proposed for diverse corrupted matrices. Resulting from the separable structure of the proposed model, the convex optimization problem can be solved efficiently by adopting an inexact augmented Lagrange multiplier (IALM) method. Additionally, a random projection accelerated technique (IALM+RP) was adopted to improve the success rate. From the preliminary numerical comparisons, it was indicated that for the standard robust principal component analysis (PCA) problem, IALM+RP was at least two to six times faster than IALM with an insignificant reduction in accuracy; and for the outlier pursuit (OP) problem, IALM+RP was at least 6.9 times faster, even up to 8.3 times faster when the size of matrix was 2 000×2 000.