一类非线性Schrdinger方程解的存在唯一性及其整体吸引子和维度估计

证明了一类非线性Schrdinger方程的解的存在唯一性及方程整体吸引子的存在性,并在此基础上得到了该吸引子的分形维数及Hausdorff维数。     

一类非线性Schr(o)dinger方程解的存在唯一性及其整体吸引子和维度估计

证明了一类非线性Schr(o)dinger方程的解的存在唯一性及方程整体吸引子的存在性,并在此基础上得到了该吸引子的分形维数及Hausdorff维数.     

一种新型双螺旋鲁棒混沌吸引子

通过在混沌L系统上添加一维非线性状态反馈控制器,构建了一个新的四维连续自治混沌系统,得到了奇异的螺旋鲁棒混沌吸引子。并通过DTP平台对该吸引子的相轨图进行仿真。     

公共组织动态的可控与不可控界限问题研究——基于混沌理论的范式

始于20世纪70年代初的混沌学研究,“将在确定论和概率论这两大科学体系之间架起桥梁,它将改变人们的自然观,揭示一个形态和结构崭新的物质运动世界。”作为“新科学”的一个重要代表,混沌理论为公共管理的研究提供了一个新的范式和视角。该文尝试在公共组织动态的可控与不可控界限问题上进行研究,引入点吸引子、极限环吸引子的收敛性和奇异吸引子的发散性博弈的理念,以期能够对当前国内外在这一问题上研究的缺失作出有益的探索。     

基础科学

一类独立的动态投入产出模型；模糊命题演算系统L^＊的简化与独立性；代数教学中的模式直观；Banach空间中非线性奇异两点边值问题的多重正解；迭代函数系统的吸引子和OSC集；战斗对策：有约束极小极大途径（Ⅰ）；具有三个年龄阶段的单种群自食模型。[编者按]     

基于信号子空间的麦克风阵语音增强算法

分析了信号子空间方法可以提高信噪比的原因,讨论了信号子空间方法在语音增强中的应用及信号子空间分解的常用方法.同时,将将单个麦克风信号子空间语音增强方法推广到多个麦克风的情况,并结合了波束形成算法.实验结果表明,基于信号子空间的麦克风阵语音增强算法消噪后语音的波形失真很小,信噪比提高多.     

具有非线性边界耗散的四阶方程整体解的不存在性分析

物理学新现象的出现,在该领域内产生了对孤立子及混沌问题的探究,并出现了一些带有非线性耗散的方程,因此文中将具有非线性边界耗散的四阶方程作为研究对象,并对该方程的整体解进行不存在性分析。首先,运用变分法获取整体弱解的存在性,将Gronwall不等式与Galerkin方法和积分估计法结合进行恰当的先验预估计并研究解的渐近特性,通过积分不等式利用Sobolev嵌入定理和吸引子存在定理证明在内积空间中整体吸引子的存在性,同时得到了吸引子的存在条件;其次,引进位势井和井外集合,运用H?lder不等式与Galerkin方法结合给定初始能量条件,得到整体解存在的门槛结果,在该方程及给定的初始条件满足区间内单调递增条件时,利用反证法可证明方程解不存在整体解,即局部解可在限定时间内实现爆破。     

基于MIMO-OFDM系统下的子空间算法研究

信道估计是4G研究中的关键技术之一,本文基于二阶统计量的子空间盲信道估计算法,对子空间算法以及在MIMO-OFDM系统下的子空间算法进行了分析,通过计算接收信号矢量的自相关求得噪声子空间。     

广义Boussinesq方程的整体吸引子及其维数估计

在整体解唯一存在的基础上,研究了广义Boussinesq方程的整体吸引子和有限维的Hausdorff维数和分形维数.     

用Mathematica 4绘制混沌模拟图

介绍数学软件Mathematica4的免安装使用方法，并用来绘制混沌吸引子的模拟图形。     

Preservation of a two-wing Lorenz-like attractor with stable equilibria

In this paper, we present the preservation of a two-wing Lorenz-like attractor when in the Lorenz system a feedback control is applied, making two of its equilibria a sink. The forced system is capable of generating bistability and the trajectory settles down at one stable equilibrium point depending on the initial condition when the forced signal is zero. Due to a variation in the coupling strength of the control signal the symmetric equilibria of the Lorenz system move causing the basins of attraction to be the dynamic bounded regions that change accordingly. Thus, the preservation of a two-wing Lorenz-like attractor is possible using a switched control law between these dynamic basins of attraction. The forced switched systems also preserve multistability regarding the coupling strength and present multivalued synchronization according to the basin of attraction in which they were initialized. Bifurcations of the controlled system are used to exemplify the different basins generated by the forcing. An illustrative example is given to demonstrate the approach proposed.     

深圳成份股指数收益率序列的分形维

本文利用Ｇ－Ｐ算法计算了深圳成份股指数的分形维为３．８。而这就是证券市场运行系统的混沌吸引子的维数。因此,虽然证券市场的运行是千变万化的,决定其变化的因素很多,但是本质因素只有４个。     

On dynamics analysis of a novel three-scroll chaotic attractor

This paper reports a novel chaotic member to the three-dimensional smooth autonomous quadratic system family, which is derived from the classical Chen system but exhibits a three-scroll chaotic attractor. The basic dynamical properties, such as Lyapunov exponents, fractal dimension, Poincaré map and chaotic dynamical behaviors of the new chaotic system are studied, either numerically or analytically. Simulation results clearly show that this is a novel chaotic system and deserves further detailed investigation.     

信息技术环境下组织创新的系统行为及其复杂性

 定义了信息技术环境下企业组织创新的概念内涵;利用不连续生长曲线、吸引子、吸子盆、匹配图景、分形和非线性发展模式等复杂系统理论与方法探讨了企业组织创新的系统行为及其复杂性。结果表明：（1）信息技术环境下企业组织创新是一项协同性的系统创新,决定系统行为的四个基本变量是组织文化创新、业务流程创新、组织结构创新和信息技术创新;（2）组织文化既是稳定的吸引子,又是不稳定的混沌吸引子;组织文化创新是整个组织创新的先导和保障;（3）通过高绩效的组织创新,处于混沌边缘的组织能够跃迁到一个新的、具有更高复杂性和一致性的动态稳定阶段;（4）在组织系统不连续生长周期的相对稳定阶段和相对不稳定阶段,企业通常分别实施渐进性组织创新和根本性组织创新。     

Fault diagnosis for analog circuits based on chaotic signal excitation

A fault diagnosis method for analog circuit is proposed in this paper. An all-purpose amplifier is taken as the typical circuit under test (CUT). The chaotic signal, which is generated by an improved Chua's circuit, is employed as the excitation signal of CUT. The algorithm for phase-space reconstruction of chaotic time series is a combination algorithm of multiple autocorrelation and Γ-test. The circuit state is estimated based on detecting the geometric change of Chua's attractor with a data-mining approach. For the purpose of information fusion, another eight features are extracted from the testing data to comprehensively determine the CUT states. A discussion is made for comparing the effectiveness of each feature according to the testing results.     

基于混沌理论的洪水灾害动力机制

随着全球气候的变化和人类活动的加强 ,洪水灾害越来越严重 ,严重影响了社会经济的发展。因此 ,研究洪水灾害的动力机制 ,进行有效地防灾减灾已迫在眉睫。以天山黄水沟突发性洪水为例 ,应用混沌理论对洪水灾害的动力机制做了深入研究。研究中 ,计算分析了黄水沟洪峰流量时间序列的关联分维数(D2 )、Kolomogorov熵 (K)等非线形特征。结果表明 :黄水沟突发性洪水具有混沌动力系统的一些特征 ,洪峰流量的时间序列分布是一个确定的低维混沌吸引子 ,黄水沟洪水可预报时间的平均长度约为 8天     

分形插值曲线的MATLAB实现

自然界中存在的许多现象具有分形特征,传统的Euclid 空间对具有分形特征的自然界形态仿真具有一定困难.对此可以用分形插值来拟合自然界形态.分形插值函数是由迭代函数系统(IFS)实现的.通过离散的数据点构成分形插值函数,可以证明分形插值函数是这个IFS唯一的吸引子.利用MATLAB矩阵运算与图形绘制功能,实现离散数据点的分形插值拟合.试验结果表明.该算法具有简捷直观的特点.     

DSP-based implementation of fast terminal synergetic control for a DC–DC Buck converter

Finite time convergence based on robust synergetic control (SC) theory and terminal attractor techniques is investigated. To this end a fast terminal synergetic control law (FTSC) is applied to drive a DC–DC Buck converter via simulation and through a dSpace based experimental setup to validate the approach. As robust as sliding mode control, the synergetic approach used is chattering free and provides rapid convergence. Efficacy of the proposed fast terminal synergetic controller is tested for step load change and output voltage variation and results compared to classical synergetic and PI control. Experimental validation using dSpace DS1104 confirms the results obtained in simulation showing the soundness of this approach compared to synergetic and PI controllers.     

Structural vibration control

Undesirable time-variable motions of dynamical structures (e.g. scales, balances, vibratory platforms, bridges and buildings) are mainly caused by unknown or uncertain excitations. In a variety of applications it is desirable or even necessary to attenuate these disturbances in an effective way and with moderate effort. Hence, several passive as well as active methods and techniques have been developed in order to treat these problems. However, employment of active techniques often fails because of their considerable financial costs. We propose an affordable control scheme which accounts for the above-mentioned deficiencies. In addition, we allow constraints on control actions. Furthermore, the number of control inputs (actuators) may be arbitrary, i.e., the system may be mismatched. The scheme is based on Lyapunov stability theory and, provided that the bounds of the uncertainties are a priori known, a stable attractor (ball of ultimate boundedness) of the structure can be computed. In case measurement errors or uncertainties, respectively, are significant, it is shown how the Lyapunov-based control scheme may be combined with a fuzzy control concept. The effectiveness and behavior of the control scheme is demonstrated on two simplified models of elastic structures such as a two story building and a bridge subjected to a moving truck.