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孙水玲 《广东技术师范学院学报》2002,(4):1-5
本文利用向量李雅普诺夫函数法 ,分别研究了具有自互联作用和不具有自互联作用的离散线性时变大系统的关联稳定性 ,给出判别系统稳定性的条件。 相似文献
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刘轩黄 《江西电力职业技术学院学报》2002,15(1):1-5
放弃Luenberger状态观测器理论对系统完全可观测性的要求 ,提出了一般离散线性时变系统的状态观测器的设计方法。对j =i,i- 1,给出了系统完全 (i,j,Ti)可重构的新概念 ,且给出了可重构的充要条件 相似文献
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王中生 《衡阳师范学院学报》1990,(6)
本文利用“区间矩阵稳定性”理论,加权和标量Liapunov函数方法及向量Liapunov函数方法,讨论了一类大系统的平稳振荡,得到了一类大系统存在平稳振荡的两个充分条件。 相似文献
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宋乾坤 《湖州师范学院学报》2004,26(1):12-16
引进了多滞后时变区间动力系统的指数稳定的概念,用矩阵测度和时滞微分不等式研究了具有多滞后的时变区间动力系统χ(t)=N[P(t),Q(t)]χ(t) ∑(i=1,m)N[Pi(t),Qi(t)]χ(t-τi),τi0(i=1,2,…,m)的指数稳定性,得到了其指数稳定的一些判据,并给出了应用的例子,改进和推广了前人的工作。 相似文献
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程晓亮 《鞍山师范学院学报》2009,11(2):7-9
对于一类广义离散时变系统,通过Lyapunov方程的建立,给出了系统因果且渐近稳定的充分必要条件,基于这一结果,利用对应的Riccati方程进一步研究了系统的能稳定性问题,给出了系统能稳定的充分必要条件.最后,举例说明了所得结果的正确性. 相似文献
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研究一类线性离散时变系统的故障估计问题.首先,通过引入一种规则化最小二乘标准来作为故障估计问题的性能指标;进而,应用最小二乘固定滞后平滑算法,得到了估计问题可解的充要条件,给出了故障和状态的一步滞后平滑估计器和两步滞后平滑估计器.算例验证了本文所提方法的有效性. 相似文献
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目的:采用实验方法研究变风量全局优化问题,利用迭代学习控制策略优化动态控制性能,获得变风量系统在系统层次的最优。创新点:1.采用全新的兼有变风量和变水量功能的实验平台;2.引入递阶优化控制理论,建立变风量系统的动态和稳态模型;3.采用先进控制策略,如自校正比例积分微分(PID)控制和迭代学习控制等。方法:1.将系统进行分解(图4),并建立系统稳态模型(公式6–11)、动态模型(公式12–15)和能耗模型(公式16);2.在此基础上采用变速积分 PID、自校正 PID 和迭代学习控制对系统底层进行动态控制,在系统整体优化中引入迭代学习。结论:1.先进控制策略的引入有利于优化变风量系统动态控制过程;2.采用基于迭代学习的优化方法,可使系统节能约18.2%。 相似文献
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数字电路系统设计与制作的一般方法 总被引:2,自引:0,他引:2
介绍一种数字电路系统设计与制作的一般方法。分析数字电路系统的各组成电路作用和设计原则,把复杂的数字电路系统逐步划分成不同层次、相对独立的子系统;通过对子系统的逻辑关系、时序等的分析,选用合适的各种中大规模集成数字电路器件来实现;按照由大到小,由整体到局部,再由小到大,由局部到整体的设计方法进行系统设计,实现利用现有的数字电路器件来设计与制作具有各种复杂逻辑关系的数字电路系统。 相似文献
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研究MIMO离散非线性系统的自适应Backstepping控制,对包含两个三阶子系统的MIMO系统推出稳定的自适应控制器设计,并利用关键性引理和投影算法的性质证明了闭环系统的所有信号有界和保证跟踪性能. 相似文献
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Kjeld B. Poulsen Søren H. Jensen Elsa Bach John F. Schostak 《Educational Action Research》2013,21(1):75-106
During the past five decades occupational researchers have documented that bus drivers’ health is worse than in almost any other profession. The authors suggest that the reason there has not been any successful attempt to change this situation is because the focus until now on removing statistically associated external risk factors has been too narrow. The article describes a project whose purpose was to improve the health and well‐being of 3500 Copenhagen bus drivers. At the end, more than 200 interventions were implemented. The authors adopted a new approach of combining epidemiological results and qualitative methodologies, creating a broader explanatory foundation for action, linked by repetitive processes of critical reflection, which was central to defining problems, explaining causes, developing sufficiently effective interventions and measuring effects. The project revealed the importance of several new and potentially preventable factors involving such issues as lifestyle, private stressors and inappropriate management. During the project period an evaluative framework was developed to explore and measure the complex effects of multiple interventions. Three years after the interventions were launched, follow‐ups revealed remarkable improvements such as reductions in stress and body pains, an increase in satisfaction, and improvements in management and the drivers’ cabin. This article is the story of a methodological journey, from classical epidemiology to an approach combining the strengths of survey (broad coverage), qualitative methods (in‐depth focus) followed by critical reflections and ending with action research. 相似文献
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This study presents a quantitative approach based on Differential Item Functioning analysis within the Item Response Theory framework, to quantify gender differences in tackling specific mathematical items. We use this approach to explore two crucial topics in mathematics education (misconceptions in decimal numbers, and estimation) by analysing answers given by Italian students to specific mathematical items taken from a sample of 1400 items administered in INVALSI tests since 2008. For each item, we have a sample of 30,000 students per year, statistically representative of the entire Italian student population. The results section presents a didactic interpretation of the statistical evidence and shows how interdisciplinarity between statistics and mathematics education, with a mixed-method approach (Johnson & Onwuegbuzie, 2004), represents a good approach to exploring the gender gap in relation to specific constructs of math education. This approach, common in many disciplines, can also make an interesting contribution to mathematics education research. 相似文献
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Xiang Ji Jing-feng Bai Guo-feng Shen Ya-zhu Chen 《Journal of Zhejiang University. Science. B》2009,10(9):639-647
et tissue by either moving single focal point or generating multiple loci simultaneously. 相似文献
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Recently a new clustering algorithm called 'affinity propagation' (AP) has been proposed, which efficiently clustered sparsely related data by passing messages between data points. However, we want to cluster large scale data where the similarities are not sparse in many cases. This paper presents two variants of AP for grouping large scale data with a dense similarity matrix. The local approach is partition affinity propagation (PAP) and the global method is landmark affinity propagation (LAP). PAP passes messages in the subsets of data first and then merges them as the number of initial step of iterations; it can effectively reduce the number of iterations of clustering. LAP passes messages between the landmark data points first and then clusters non-landmark data points; it is a large global approximation method to speed up clustering. Experiments are conducted on many datasets, such as random data points, manifold subspaces, images of faces and Chinese calligraphy, and the results demonstrate that the two approaches are feasible and practicable. 相似文献
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研究含径向对流,辐射压为主的吸积盘的径向-环向的不稳定性,结果发现:即使存在很小的径向对流也对声摸产生较大的影响.另一方面,环向扰动的增加,使得热模变得更不稳定,而粘滞模更加稳定,对声摸没有影响. 相似文献
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刘小龙 《吕梁高等专科学校学报》2009,25(1)
主要研究了不同群色散剖面色散缓变光纤(DDF)中脉冲传输的展宽因子,并将DDF展宽特性的仿真结果与单模光纤(SMF)进行对比;另外分析了二阶色散以及高阶非线性效应在DDF中产生的调制不稳定性,从而对DDF做了一个较为全面的分析. 相似文献