离散线性开关系统切换的模糊方法

在已知离散线性开关系统全局渐近稳定前提下，将线性开关系统切换问题转化为相应T－S模型模糊区域划分问题，通过在线实时调整T－S模型隶属函数参数来确定模糊区域，以二阶离散线性开关系统为例，给出了实现系统全局渐近稳定的模糊切换策略，该方法可扩展到高阶线性开关系统，计算机仿真证实该方法简捷，有效。     

具有m个开关系统的渐近稳定性

研究了一类具有m个开关系统的渐近稳定性,借助于多重Lyapunov函数,给出了该系统全局渐近稳定的充分条件,部分地改进了前人的结果。     

线性开关系统的饱和控制

利用开关系统切换的特点研究了线性开关系统的饱和控制问题,在较弱的条件下,得到了开关系统饱和镇定的结果,即构成开关系统的每个子系统可以是非稳定的,但假定由开关系统构成的某个凸组合系统是可稳的.借助于Lyapunov函数设计饱和控制器,基于凸组合系统的稳定性设计切换规律,引入设计参数满足控制器实现的条件,使开关系统局部渐近稳定.     

一类线性开头系统的渐近稳定性

研究一类线性开关系统的渐近稳定性问题。针对不满足完备性条件的开关系统，利用Lya-punov函数技术，给出了系统渐进稳定的一个充分条件，并举例说明了该方法的实际应用。     

反步法在三相电压型脉冲调宽逆变器控制中的应用

针对三相电压型脉冲调宽(pulse-width-modulation,PWM)逆变器这个时变的、多模态的非线性系统,应用开关函数建立了系统数学模型,引入开关周期平均算子将离散的系统化为连续系统,得到具有参数严格反馈形式的二阶非线性多输入多输出系统数学模型.并对此模型应用反向递推方法,通过逐步选择虚拟控制量和构造李雅普诺夫函数,使每个状态分量具有适当的渐近特性,实现整个系统在大扰动下的全局渐近稳定性,进而得到反馈控制律的一般表达式.将三相电压型PWM逆变器系统参数代入后得到其反馈控制规律.最后通过仿真实验验证了该方法的有效性和正确性.     

基于改进NSGA-Ⅱ算法的开关磁阻电机再生制动优化控制方法

针对采用传统优化算法优化开关磁阻电机再生制动控制参数存在制动能量回馈效率低及制动转矩脉动系数大的问题,提出一种基于渐近约束支配法则的双目标非支配排序遗传算法。首先针对传统双目标非支配排序遗传算法优化开关磁阻电机再生制动控制参数时存在易陷入局部最优解等不足,提出一种渐近约束支配法则,再将基于渐近约束支配法则的双目标非支配排序遗传算法应用于开关磁阻电机再生制动控制参数的优化,并对其效果进行了仿真验证,同时与传统双目标非支配排序遗传算法进行了对比分析,结果表明:基于渐近约束支配法则的双目标非支配排序遗传算法不仅有效解决了易陷入局部最优解的问题,而且显著提高了开关磁阻电机再生制动效率并降低了其转矩脉动系数,取得了满意的优化效果。     

具有线性漂移的随机多模态系统的反馈镇定

研究具有线性漂移的、以Markov链为开关函数的多模态随机系统的反馈镇定,通 过建立多模态随机系统的均方渐近平坦性定理,给出具有线性漂移的多模态随机系统和线性 多模态随机系统的反馈镇定方案,并给出控制器设计中的计算方法,用仿真实例验证了该方 法的效果.     

滞环非线性系统的加权自适应控制

本文通过引入一个非线性补偿环节和一个开关量函数,解决了滞环非线性系统的自适应 控制问题,并分别对滞环宽度已知和未知情况,建立了大范围渐近收敛和稳定的加权自适应控 制算法.这种算法具有渐近最优的控制效果,能用于非最小相位系统.仿真结果表明,该算法 具有良好的动态性能.     

一类开关切换系统的输出反馈镇定

对一类子系统为线性的开关切换系统进行观测器设计，并给出系统动态输出反馈可镇定的充分条件。在所设计的观测器基础上，以系统状态的观测值为依据设计各子控制器和切换方案，使整个闭环系统是指数渐近稳定的。对于切换时间间隔受限制的情况，给出了相应的动态输出反馈可镇定条件和镇定控制方案。实例仿真结果表明，所给出的设计方案是可行的。     

一类具有相似结构的不确定组合大系统的观测器设计

讨论了非线性组合大系统渐近观测器的设计问题。对一类具有相似结构的非线性不确定组合大系统构造出其鲁棒渐近观测器，并举例说明所提出的渐近观测器的设计方法。     

基于语义事务分解的可串行性

数据库应用中长事务的出现严重降低了系统的性能，一些研究者为解决这一问题提出了利用事务的语义信息对事务进行分解的方法，但所得结论仍然存在缺陷．本文从用户定义的后续集出发给出了正确步进串行历史的概念，可以很容易证明正确步进串行历史是用户可接受的正确历史，并以此作为判定一个历史是否正确的基础．重后，证明了当用户给出的后续集满足约束2时，优化前驱图的无环性是判定一个正确历史的充要条件．     

Solution of problem of identification of time shift of pseudorandom sequences on the basis of nonlinear probabilistic criteria

A solution of the problem of identification of the time shift of pseudorandom sequences received against a background of interference is proposed. The solution is based on a nonlinear probabilistic criterion—the criterion of minimum a posteriori integral estimation error. An algorithm of nonlinear parametric identification that yields a solution of the problem is synthesized. A numerical example of the identification of the time shift of a concrete sequence that confirms the effectiveness and adequate degree of efficiency of the algorithm proposed in the study is presented.     

Correctness of Algebraic Extensions of Models of Classification Algorithms

The binary representation of each classification from a subset of a space of admissible classifications is considered. A metric in a unit cube is introduced, and a correct algebra of classification algorithms is constructed. The correctness and completeness of a model of classification algorithms are proved. An example of construction of a complete model for a classification problem is considered.     

Submodular Functions in Problems of Synthesis of Networks

It is established that any problem of minimization of a general submodular function is the problem of determination of a minimum cut in a network if, for an arbitrary set, the dual function is defined as the sum of its values on the two-element subsets of this set. This result is used to synthesize a network with the help of a cut submodular function.     

Palindromic complexity of codings of rotations

We study the palindromic complexity of infinite words obtained by coding rotations on partitions of the unit circle by inspecting the return words. The main result is that every coding of rotations on two intervals is full, that is, it realizes the maximal palindromic complexity. As a byproduct, a slight improvement about return words in codings of rotations is obtained: every factor of a coding of rotations on two intervals has at most 4 complete return words, where the bound is realized only for a finite number of factors. We also provide a combinatorial proof for the special case of complementary-symmetric Rote sequences by considering both palindromes and antipalindromes occurring in it.     

Stabilisation of infinitesimally rigid formations of multi-robot networks

This article considers the design of a formation control for multivehicle systems that uses only local information. The control is derived from a potential function based on an undirected infinitesimally rigid graph that specifies the target formation. A potential function is obtained from the graph, from which a gradient control is derived. Under this controller the target formation becomes a manifold of equilibria for the multivehicle system. It is shown that infinitesimal rigidity is a sufficient condition for local asymptotical stability of the equilibrium manifold. A complete study of the stability of the regular polygon formation is presented and results for directed graphs are presented as well. Finally, the controller is validated experimentally.     

无线投影机网关系统设计

无线投影机网关是投影机的附属设备,在PC与投影机之间建立无线连接,将PC的屏幕图像传输到投影机上,从而使PC摆脱与投影机之间的连线束缚.该网关设备在设计中采用的GX533是AMD的一款嵌入式x86处理器,GX533在机顶盒、网络终端、瘦客户机、廉价电脑等领域有着广泛的应用.分析了GX533处理器及其南桥控制器的结构原理,在此基础上介绍无线投影机网关的系统设计.     

The boundedness of all products of a pair of matrices is undecidable

We show that the boundedness of the set of all products of a given pair Σ of rational matrices is undecidable. Furthermore, we show that the joint (or generalized) spectral radius ρ(Σ) is not computable because testing whether ρ(Σ)1 is an undecidable problem. As a consequence, the robust stability of linear systems under time-varying perturbations is undecidable, and the same is true for the stability of a simple class of hybrid systems. We also discuss some connections with the so-called “finiteness conjecture”. Our results are based on a simple reduction from the emptiness problem for probabilistic finite automata, which is known to be undecidable.     

Complexity of approximation of 3-edge-coloring of graphs

The problem to find a 4-edge-coloring of a 3-regular graph is solvable in polynomial time but an analogous problem for 3-edge-coloring is NP-hard. To make the gap more precise, we study complexity of approximation algorithms for invariants measuring how far is a 3-regular graph from having a 3-edge-coloring. We show that it is an NP-hard problem to approximate such invariants with an error O(n1−ε), where n denotes the order of the graph and 0<ε<1 is a constant.     

Generation of root functionals of a system of polynomials

A root functional is a functional that is defined over a polynomial ring and annihilates the ideal of polynomials. The concept of a root functional is a generalization of the concept of a root to the case of multiple roots. This article considers a bilinear operation of generation of root functionals for a system of polynomials in variables, which allows one to construct a root functional from two root functionals. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 22–46, January–February 2008.