非线性多变延迟奇异摄动问题的稳定性分析   总被引：1，自引：0，他引：1  

王洪山  张诚坚 《东南大学学报》2003,19(2)

讨论了形如x′(t) =f(x(t) ,x(t -τ1(t) ) ,… ,x(t -τm(t) ) ,y(t) ,y(t -τ1(t) ) ,… ,y(t-τm(t) ) )和εy′(t) =g(x(t) ,x(t -τ1(t) ) ,… ,x(t -τm(t) ) ,y(t) ,y(t -τ1(t) ) ,… ,y(t -τm(t) ) ) (0 <ε 1)的非线性多变延迟奇异摄动系统的理论解的稳定性 ,得到了系统稳定的一个充分条件 .在此条件下还证明了隐式Euler方法的数值解是稳定的 .  相似文献   

Incremental training intensities increases loads on the lower back of elite female rowers     

Erica M. Buckeridge  Anthony M.J. Bull  Alison H. McGregor 《Journal of sports sciences》2016,34(4):369-378

Lumbar-pelvic kinematics change in response to increasing rowing stroke rates, but little is known about the effect of incremental stroke rates on changes in joint kinetics and their implications for injury. The purpose of this study was to quantify the effects of incremental rowing intensities on lower limb and lumbar-pelvic kinetics. Twelve female rowers performed an incremental test on a rowing ergometer. Kinematic data of rowers’ ankle, knee, hip and lumbar-pelvic joints, as well as external forces at the handle, seat and foot-stretchers of the rowing machine were recorded. Inter-segmental moments and forces were calculated using inverse dynamics and were compared across stroke rates using repeated measures ANOVA. Rowers exhibited increases in peak ankle and L5/S1 extensor moments, reductions in peak knee moments and no change in peak hip moments, with respect to stroke rate. Large shear and compressive forces were seen at L5/S1 and increased with stroke rate (P < 0.05). This coincided with increased levels of lumbar-pelvic flexion. High levels of lumbar-pelvic loading at higher stroke rates have implications with respect to injury and indicated that technique was declining, leading to increased lumbar-pelvic flexion. Such changes are not advantageous to performance and can potentially increase the risk of developing injuries.  相似文献   

Non-Rigid Medical Image Registration with Joint Histogram Estimation Based on Mutual Information   总被引：1，自引：0，他引：1  

陆雪松  张素  苏和  陈亚珠 《天津大学学报(英文版)》2007,13(6):452-455

A mutual information-based non-rigid medical image registration algorithm is presented. An approximate function of Hanning windowed sinc is used as kernel function of partial volume (PV) interpolation to estimate the joint histogram, which is the key to calculating the mutual information. And a new method is proposed to compute the gradient of mutual information with respect to the model parameters. The transformation of object is modeled by a free-form deformation (FFD) based on B-splines. The experiments on 3D synthetic and real image data show that the algorithm can converge at the global optimum and restrain the emergency of local extreme.  相似文献   

广义线性系统极点配置的方法     

杨战民  刘利华  谭宏武  王社宽 《咸阳师范学院学报》2004,19(2):5-7

研究了广义线性系统的极点配置问题，利用矩阵的奇异值分解和矩阵的广义逆得到了广义线性系统的奇异值标准形，使得广义线性系统的极点配置问题转变为正常系统的极点配置问题，从而给出广义线性统极点配置的一种新方法。  相似文献   

二元二次Jacobi猜想的求逆公式     

张跃辉  严丹 《天津工程师范学院学报》2007,17(1):5-7

利用行列式的基本知识和计算技巧,给出了复数域上一次与二元二次Jacobi猜想的一个简明的求逆公式,验证了Abhyankar多元幂级数在上述情形下的形式求逆公式。  相似文献   

关于“沙子的开采”的评注     

董永权 《唐山师范学院学报》2001,23(5):45-47

从评阅者的角度对求解这道题目中值得注意的问题作了阐述，指出了学生的解答中好的作法及不足之处。  相似文献   

r-首尾和循环矩阵求逆的一种算法     

朱泉涌  沈光星 《丽水学院学报》2004,26(5):16-19

引进了γ-首尾和循环矩阵的新概念，利用多项式矩阵理论，给出了一种γ-首尾和循环矩阵的算法。用来计算它的逆矩阵或群逆。  相似文献   

广义正定矩阵的逆与行列式     

杨炳良 《湖州师范学院学报》1992,(6)

在本文中(1)证明了参考文献[2]与[3]中所定义的两类广义正定矩阵的逆仍是同种类型的广义正定矩阵;(2)给出了参考文献[2]中广义正定矩阵的行列式满足如下不等式|A|≤a_(n n)P_(n-1)这里P_(n-1)是A的n-1阶顺序主子式.进一步有|A|≤a_(n n)a_(n-1 n-1)…a_(22)a_(11)  相似文献   

Weibull分布下双应力交叉步加试验的逆矩估计法     

鲍志晖 《黄山学院学报》2007,9(3):9-11

论述了Weibull分布下双应力交叉步加试验的时间折算公式及数据统计分析的逆矩估计法。  相似文献   

漫画刍议--从漫画进课堂说起     

冯贵波 《廊坊师范学院学报》2002,18(2):115-117

试从对中国漫画艺术的回顾，阐述对漫画的艺术形式、漫画的社会功能、漫画的艺术造型等问题的观点，澄清人们长期 对漫画艺术的一些误解，以利于漫画课堂教学的实施。  相似文献