共查询到20条相似文献，搜索用时 93 毫秒
1.
高智中 《安徽科技学院学报》2011,25(3):22-25
分析了一个二维离散超混沌系统吸引子的存在性,通过数值模拟得到系统随参数变化的分岔图,Lyapunov指数谱和吸引子图像,说明了系统由周期运动到超混沌运动的转迁过程。利用X|X|控制方法,系统的超混沌行为可以有效的控制并得到稳定的周期轨道,数值仿真表明了这个方法的可行性和有效性。 相似文献
2.
混沌来自非线性。非线性电路中有十分丰富的分岔和混沌现象。本文介绍了蔡氏电路的结构,通过调整电路的参数,用示波器可以观察到直流平衡态、Hopf分岔、倍周期分岔、单涡卷混沌吸引子、周期性窗口和双涡卷混沌吸引子等非线性动力学行为,表明混沌是一种确定性系统中出现的貌似不规则的有序运动本质特征。 相似文献
3.
熊伟 《湖北第二师范学院学报》2009,26(8):79-80
混沌来自非线性。非线性电路中有十分丰富的分岔和混沌现象。本文介绍了蔡氏电路的结构,通过调整电路的参数,用示波器可以观察到直流平衡态、Hopf分岔、倍周期分岔、单涡卷混沌吸引子、周期性窗口和双涡卷混沌吸引子等非线性动力学行为,表明混沌是一种确定性系统中出现的貌似不规则的有序运动本质特征。 相似文献
4.
通过一系列动力学分析,验证了一个纠缠系统是混沌的.当混沌纠缠实现时,所有的平衡点是不稳定的鞍结点.数值计算显示这个系统有一个正的Lyapunov指数,这表明该系统是混沌的.通过局部放大的分岔图验证了系统由倍周期分岔通向混沌的过程,并分析了该混沌系统的Hopf分岔现象. 相似文献
5.
本文构造了一个新的四维分数阶混沌系统,与至少含有一个不稳定平衡点的一般分数阶混沌系统不同的是,该系统仅有两个稳定平衡点.首先给出了两个平衡点局部渐近稳定的充分条件,通过数值模拟验证了该系统的混沌吸引子与两个稳定平衡点共存.然后,基于分数阶Lyapunov稳定性理论,在误差系统保留非线性项的情况下,利用反馈控制实现了此系统的同步,数值模拟进一步证实了结论的正确性. 相似文献
6.
对一类改进的Chua系统进行定位系统的隐藏吸引子研究。首先,通过对改进的Chua系统平衡点稳定性进行分析,确定系统在一定条件下有一对纯虚特征根。由于存在一对纯虚特征根,系统在平衡点处就会出现Hopf分支。然后,通过描述对原系统进行变换,以引入一系列连续函数序列对系统进行解析数值算法迭代,与定位稳定周期解的谐波线性化方法结合定位原系统的隐藏吸引子。通过MATLAB数学软件进行数值模拟得到系统的Lyapunov指数谱和分岔图,从而为隐藏吸引子的存在性提供依据。运用相关程序在MATLAB的帮助下制作出系统的隐藏吸引子相图,得出在这类改进的Chua系统中存在隐藏吸引子的结论。 相似文献
7.
李险峰 《咸阳师范学院学报》2006,21(4):11-13
用数值模拟的方法研究了二维滞后Logistic系统。对于二维滞后Logistic系统的混沌的形成过程进行了探讨。理论分析了二维Logistic映射的分岔,用分岔图、Lyapunov指数图和发生Hopf分岔的点附近的相图,有选择地研究了控制参数空间中两条轨线变化时系统行为的演化. 相似文献
8.
9.
一类新超混沌系统及其自同步 总被引：2，自引：0，他引：2
高智中 《常熟理工学院学报》2011,25(8):31-34
基于一个三维混沌系统构造了一个新的四维超混沌系统,利用系统的分岔图、Lyapunov指数谱图和相图分析方法研究了该系统的运动规律．根据线性系统稳定性定理,设计了一种非线性反馈控制器,实现了该超混沌系统的自同步,数值模拟结果验证了理论分析的正确性． 相似文献
10.
袁地 《安阳师范学院学报》2008,(5):27-31
通过数值计算、理论推导分析了一个类Lorenz混沌系统的基本动力学特性,并通过数值仿真、相图、Poincare截面图和功率谱研究了这个系统的混沌行为。然后,构建一个受控系统并利用Lyapunov指数谱、分叉图分析了该系统混沌吸引子的形成机制。结果表明．该系统混沌吸引子可由两个卷形状演化为一个卷形状,并最终通过倍周期分叉的过程演化为周期运动的形状。 相似文献
11.
Chris Du Feu 《Teaching Statistics》2009,31(3):66-71
A classroom practical exercise exploring the reliability of a basic capture‐mark‐recapture method of population estimation is described using great whale conservation as a starting point. Various teaching resources are made available. 相似文献
12.
张红旗 《廊坊师范学院学报》2010,(3):80-83
公推直选乡镇长与乡镇党委书记出现的时间、发展现状与趋势、制度依据、选举成本,以及乡镇长与乡镇党委书记在乡镇政权中的作用有明显的不同。在我们看来,直接选举乡镇党委书记,发展的空间更广阔,对乡镇民主建设与乡镇政府职能转型所起的作用更大。 相似文献
14.
15.
（参考译文）。
向量也可和数做乘法．向量a与数字A的乘积定义为向量aλ—λa,它的绝对值是向量a的绝对值和数字A的绝对值的乘积, 相似文献
16.
乔南 《中学数学教学参考》2008,(11)
Vectors may also be multiplied by a number. The productof the vector a by the number λ is defined as the vector a λ=λa, the absolute value of which is obtained by multiplying theabsolute value of the vector a by the absolute value of thenumber λ, i. e. |λa|=|λ||a|, the direction coinciding withthe direction of the vector a or being in the opposite sensedepending on whether λ>0 or λ<0. If λ=0 or a=0, then λ a 相似文献
17.
18.
The concept of metacognition refers to one’s knowledge and control of one’s own cognitive system. However, despite being widely
used, this concept is confusing because of several reasons. First, sometimes it is not at all clear what is cognitive and
what is metacognitive. Second, researchers often use the same term, namely, “metacognition” even when they refer to very different
aspects of this complex concept. Alternatively, researchers may use different terms to indicate the same metacognitive elements.
Another foggy matter is the interrelationships among the various components of metacognition discussed in the literature.
This conceptual confusion regarding the concept of metacognition and its sub-components calls for in-depth theoretical and
conceptual clarifications. The goal of this article is to portray a detailed example of a conceptual analysis of meta-strategic
knowledge (MSK) which is one specific component of metacognition. This specific example is used to draw a general model for
conceptual analyses of additional metacognitive components. The approach suggested here is to begin with a clear definition
of the target sub component of metacognition, followed by a systematic examination of this sub component according to several
dimensions that are relevant to metacognition in general and to that sub component in particular. The examination should include
an analysis of how the details of the definition of the target sub-component refer to: (a) general theoretical metacognitive
issues raised by prominent scholars; (b) definitions formulated and issues raised by other researchers who have investigated
the same (or a similar) sub-component and, (c) empirical findings pertaining to that sub-component. Finally, it should be
noted that since metacognition is a relational rather than a definite concept it is important to situate the context within
which the conceptual analysis takes place. 相似文献
19.
The term professional vision points to the many nuanced ways professionals see. This paper traces the development of a professional vision of a researcher and a teacher looking at classroom practices. The researcher’s interest was to capture and study notable aspects of the teacher’s practice. Through a coding scheme, disparate classroom events were organized and analyzed to yield a researcher’s professional vision of the teacher’s practices. For the teacher, through reviewing the video records of his own classroom practices, his professional vision provided a basis for him to reflect and develop professionally. Leveraging on the work of the researcher, he initiated and transformed his own practices. Their collaboration yielded a mutually informed development of professional vision of classroom practices. In juxtaposing the two developments, the researcher and the teacher’s views can be contrasted, their distinctive interests highlighted and common grounds explored. Some implications for developing professional vision are drawn, and it is in the common grounds of the teacher’s professional development and seeing with a goal of enhancing of student learning that hold some promise of a mutual interest in developing a professional vision of classroom practices. 相似文献
20.
McSweeney and her colleagues (e.g., McSweeney, Hatfield, & Allen, 1990) have demonstrated reliable, large magnitude rate changes in maintained operants within daily sessions under a wide variety of reinforcement schedules. The present paper examined the role of schedule of reinforcement, reinforcement rate, and total amount of food access in determining those within-session rate changes. When median rates across birds were considered, all procedures resulted in a brief period of an increasing rate, followed by a modest rate loss across the major portion of the session. However, not all individuals exhibited that pattern. When the amount of food access per session was limited by lower reinforcement rates, shorter sessions, or shorter reinforcement durations, the magnitude of the withinsession rate change was reduced from that occurring without those constraints. Additionally, under the conditions that produced strong within-session rate changes, the magnitude of the within-session rate loss was correlated with the bird’s body weight. These effects are consistent with what is typically labeledsatiation. 相似文献