分数阶双指数混沌系统的自适应滑模同步

研究了分数阶双指数混沌系统的自适应滑模同步问题.通过设计滑模函数和控制器,构造了平方Lyapunov函数进行稳定性分析.利用Barbalat引理证明了同步误差渐近趋于零,获得了系统取得自适应滑模同步的充分条件.数值仿真结果表明:选取适当的控制器及与滑模函数,分数阶双指数混沌系统取得自适应滑模同步.     

分数阶不确定多混沌系统的自适应滑模同步

研究分数阶不确定多混沌系统的自适应滑模同步,通过构造滑模面,设计控制器和适应规则,能够满足滑模面的稳定性与到达性,进而得到分数阶不确定多混沌系统取得自适应滑模同步的充分性条件,研究表明:分数阶不确定多混沌系统满足在一定条件下能够取得自适应滑模同步.     

不同维分数阶混沌系统的自适应模糊滑模有限时间同步控制

针对不同维分数阶混沌系统的有限时间同步问题,提出了一个分数阶自适应模糊滑模控制方案。为增加同步误差的收敛速度,本文提出了一种新型的积分滑模面,并利用模糊逻辑系统结合分数阶自适应律估计理想控制器的未知部分。基于分数阶Lyapunov稳定性理论,设计了分数阶模糊滑模同步控制器,可使不同维分数阶混沌系统的同步误差在有限时间内达到滑模面。最后,数值仿真的结果验证了本文方法的有效性。     

超混沌分数阶Bao系统的自适应滑模同步控制

研究超混沌分数阶Bao系统自适应滑模同步,设计出分数阶滑模函数、适应规则和控制器,取得超混沌分数阶Bao系统自适应滑模同步的充分条件,文末用MATLAB数值仿真验证了所得结论.     

分数阶四维忆阻超混沌系统的滑模同步

研究了分数阶四维忆阻超混沌系统滑模同步的两种方法,设计分数阶控制器与滑模函数,获得分数阶忆阻超混沌系统滑模同步两个充分条件,研究表明:在设计适当的滑模面与控制律下,不确定分数阶忆阻超混沌系统可取得滑模同步.     

分数阶多涡卷混沌系统滑模同步的两种控制方案

研究了分数阶多涡卷混沌系统滑模同步的两种控制方案,根据分数阶微积分的相关理论给出了系统取得同步的充分性条件,结果表明:选取适当的控制律以及滑模面,分数阶多涡卷误差系统将取得混沌同步.     

分数阶复杂网络系统的滑模终端控制混沌同步

研究了两类复杂网络混沌系统的终端滑模控制问题,基于分数阶微积分,设计了分数阶非奇异终端滑模面和控制器,给出了严格的数学推理和证明过程,研究表明:适当的控制律下两类复杂网络混沌系统是终端滑模同步的.最后的仿真算例说明方法有效.     

分数阶单摆系统的积分滑模同步

基于Lyapunov稳定性理论,运用积分滑模方法研究一类不确定整数阶、分数阶单摆系统的滑模同步问题,给出了切换函数和控制律的选取方法,研究表明,在一定条件下,构建适当的积分滑模面和控制器,单摆系统的主从系统取得滑模同步.     

分数阶高阶不确定系统的自适应反演滑模同步

基于自适应反演滑模同步方法研究分数阶不确定高阶非线性混沌系统的同步问题,给出子系统的Lyapunov函数和虚拟控制,在反演设计中引入滑模函数和控制器及自适应规则得到分数阶不确定非线性混沌系统取得自适应反演滑模同步的充分条件,并把该结论平推到整数阶系统.     

一类不确定分数阶多混沌系统的终端滑模同步控制

根据分数阶系统理论利用终端滑模方法研究了分数阶不确定多混沌系统同步问题,获得了整数阶分数阶两种情形下多混沌系统取得滑模同步的充分性条件,最终结论说明设计合适的控制律和切换函数,分数阶多混沌系统取得滑模同步.     

Study of the blow-up of solutions of systems of equations of hydrodynamic type

Mathematical Notes - We study the initial boundary-value problem for three-dimensional systems of equations of pseudoparabolic type. The system is similar to the Oskolkov system, but differs from...     

Distribution of types of symmetry of tensors of high degree

The asymptotic distribution of tensors of degree N in symmetry types is studied in this paper.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 155, pp. 181–186, 1986.     

Characterization of types of asymptotic discernibility of families of hypotheses

We give a characterization of the types of asymptotic discernibility of families of hypotheses in the case of hypothetical measures that are not, in general, mutually absolutely continuous. The case when the logarithm of the likelihood ratio admits an asymptotic expansion of the type of an expansion with local asymptotic normality is examined in detail. Examples are studied.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 64–71, 1987.     

Axiomatizability of reducts of algebras of relations

In this paper, we prove that any subreduct of the class of representable relation algebras whose similarity type includes intersection, relation composition and converse is a non-finitely axiomatizable quasivariety and that its equational theory is not finitely based. We show the same result for subreducts of the class of representable cylindric algebras of dimension at least three whose similarity types include intersection and cylindrifications. A similar result is proved for subreducts of the class of representable sequential algebras. Received October 7, 1998; accepted in final form September 10, 1999.     

Lengths of periods of continued fractions of square roots of integers

Empirical study of the period’s length T of the continued fractions of $\sqrt{Q}$ (for growing integers Q) shows several strange asymptotical results, for instance, $T\leq C\sqrt{Q}\ln{Q}$ . These results show important differences between the statistics of the elements of the continued fractions of random real numbers and of square roots of random integers.