Hybrid chaotic sequence for QS-CDMA system with RAKE receiver

A class of the hybrid chaotic sequences is presented. The generator of the sequences is given and realized by the digital method. The hybrid chaotic sequences exhibit good random properties that are very important for the performance of QS-CDMA system with RAKE receiver. The performance of the system is analyzed when the hybrid chaotic sequences are used as spreading codes in a QS-CDMA system with RAKE receiver and compared with those obtained for m-se-quences and logistic sequences. The results show that the hybrid chaotic sequences are a class of very promising spreading codes for QS-CDMA system.

Design of Digital Hybrid Chaotic Sequence Generator

The feasibility of the hybrid chaotic sequences as the spreading codes in code divided multiple access(CDMA) system is analyzed. The design and realization of the digital hybrid chaotic sequence generator by very high speed integrated circuit hardware description language(VHDL) are described. A valid hazard canceledl method is presented. Computer simulations show that the stable digital sequence waveforms can be produced. The correlations of the digital hybrid chaotic sequences are compared with those of m-sequences. The results show that the correlations of the digital hybrid chaotic sequences are almost as good as those of m-sequences. The works in this paper explored a road for the practical applications of chaos.

Inverse full state hybrid projective synchronization for chaotic maps with different dimensions

A new synchronization scheme for chaotic（hyperchaotic） maps with different dimensions is presented.Specifically,given a drive system map with dimension n and a response system with dimension m,the proposed approach enables each drive system state to be synchronized with a linear response combination of the response system states.The method,based on the Lyapunov stability theory and the pole placement technique,presents some useful features：（i） it enables synchronization to be achieved for both cases of n 〈 m and n 〉 m;（ii） it is rigorous,being based on theorems;（iii） it can be readily applied to any chaotic（hyperchaotic） maps defined to date.Finally,the capability of the approach is illustrated by synchronization examples between the two-dimensional H′enon map（as the drive system） and the three-dimensional hyperchaotic Wang map（as the response system）,and the three-dimensional H′enon-like map（as the drive system） and the two-dimensional Lorenz discrete-time system（as the response system）.

Chaotic attractor transforming control of hybrid Lorenz-Chen system

Based on passive theory, this paper studies a hybrid chaotic dynamical system from the mathematics perspective to implement the control of system stabilization. According to the Jacobian matrix of the nonlinear system, the stabilization control region is gotten. The controller is designed to stabilize fast the minimum phase Lorenz-Chen chaotic system after equivalently transforming from chaotic system to passive system. The simulation results show that the system not only can be controlled at the different equilibria, but also can be transformed between the different chaotic attractors.

Hybrid Synchronization of a Chen Hyper-Chaotic System with Two Simple Linear Feedback Controllers

This paper brings attention on the hybrid synchronization of the Chen hyper-chaotic system by using some simple controllers. We give the sufficient conditions for achieving the goal by using the Lyapunov stability theory, and we verify our conclusion by numerical simulations.

Exponential synchronization of general chaotic delayed neural networks via hybrid feedback

This paper investigates the exponential synchronization problem of some chaotic delayed neural networks based on the proposed general neural network model,which is the interconnection of a linear delayed dynamic system and a bounded static nonlinear operator,and covers several well-known neural networks,such as Hopfield neural networks,cellular neural networks(CNNs),bidirectional associative memory(BAM)networks,recurrent multilayer perceptrons(RMLPs).By virtue of Lyapunov-Krasovskii stability theory and linear matrix inequality(LMI)technique,some exponential synchronization criteria are derived.Using the drive-response concept,hybrid feedback controllers are designed to synchronize two identical chaotic neural networks based on those synchronization criteria.Finally,detailed comparisons with existing results are made and numerical simulations are carried out to demonstrate the effectiveness of the established synchronization laws.

基于多种群多策略的竞争粒子群算法

针对标准粒子群算法遇到的易陷入局部最优、收敛差、求解精度低等问题,提出了多种群多策略竞争粒子群优化算法.新算法将每一代粒子根据适应度排序,将其划分为不同的子种群,并引入非线性Logistic混沌映射权重、收缩因子和混合高斯-柯西扰动机制来更新这些子种群.使用不同的粒子更新方式平衡了算法整个时期的全局搜索和局部开发能力,从而加快了收敛速度.最后,将多种群多策略竞争粒子群优化算法与标准粒子群算法和其它优化算法在11个测试函数上进行对比,结果表明,新算法在跳出局部最优解、和寻优精度方面显著优于标准粒子群算法,且有更快的收敛速度.在寻优能力和算法稳定性上大幅度强于其它对比算法.

Arbitrary full-state hybrid projective synchronization for chaotic discrete-time systems via a scalar signal

In this paper we present a new projective synchronization scheme, where two chaotic （hyperchaotic） discrete-time systems synchronize for any arbitrary scaling matrix. Specifically, each drive system state synchronizes with a linear combination of response system states. The proposed observer-based approach presents some useful features： i） it enables exact synchronization to be achieved in finite time （i.e., dead-beat synchronization）; ii） it exploits a scalar synchronizing signal; iii） it can be applied to a wide class of discrete-time chaotic （hyperchaotic） systems; iv） it includes, as a particular case, most of the synchronization types defined so far. An example is reported, which shows in detail that exact synchronization is effectively achieved in finite time, using a scalar synchronizing signal only, for any arbitrary scaling matrix.

基于Adaboost-INGO-HKELM的变压器故障辨识

针对目前变压器故障诊断准确率低的问题,提出一种多策略集成模型。首先通过等度量映射(isometric mapping, Isomap)对高维非线性不可分的变压器故障数据进行降维处理。其次,利用混合核极限学习机(hybrid kernel based extreme learning machine, HKELM)进行训练学习,考虑到HKELM模型易受参数影响,所以利用北方苍鹰优化算法(northern goshawk optimization, NGO)对其参数进行寻优。但由于NGO收敛速度较慢,易陷入局部最优,引入切比雪夫混沌映射、择优学习、自适应t分布联合策略对其进行改进。同时为了提高模型整体的准确率,通过结合Adaboost集成算法,构建Adaboost-INGO-HKELM变压器故障辨识模型。最后,将提出的Adaboost-INGO-HKELM模型与未进行降维处理的INGO-HKELM模型、Isomap-INGO-KELM模型、Adaboost-Isomap-GWO-SVM等7种模型的测试准确率进行对比。提出的Adaboost-INGO-HKELM模型的准确率可达96%,均高于其他模型,验证了该模型对变压器故障辨识具有很好的效果。

一种基于用户通勤行为的家庭能量管理优化策略

随着电动汽车快速发展,V2G技术可大幅降低家庭能量管理系统中用户的用能成本,但V2G会影响用户出行。针对此问题提出了一种基于用户通勤行为的家庭能量管理系统优化策略,通过极大似然估计和蒙特卡罗模拟构建用户出行模型,其次将杂交粒子群与混沌算法、免疫算法相融合,利用多重混沌免疫杂交粒子群算法(MCIHPSO)对目标函数进行求解,最后,通过仿真及实验验证了本文所提控制策略显著降低V2G功能对用户出勤的影响。

基于改进麻雀算法的无线传感器网络覆盖优化研究

针对基本麻雀搜索算法在无线传感器网络覆盖问题中收敛速度较慢、容易陷入局部最优等问题,提出了一个基于改进麻雀算法的优化方案。首先,利用Sobol序列和无限次折叠的ICMIC混沌映射对种群进行初始化,增加了种群遍历性和多样性,为算法的全局寻优奠定了基础。其次,引入混沌映射因子的正余弦算法策略,增强了探索者探索未知区域的能力,提高了算法的全局搜索性能。再次,利用混合变异策略加快算法收敛速度,并改善算法跳出局部最优的能力。最后,将提出的改进麻雀算法应用到无线传感器网络覆盖优化问题中进行仿真实验。仿真结果表明,提出的改进算法相比基本麻雀算法将网络节点的覆盖率提高了7%,同时增强了网络的整体性能,并具有实用性、稳定性和鲁棒性。

Mathematical Model and Its Hybrid Dynamic Mechanism in Intelligent Control of Ironmaking

A hybrid dynamic model was proposed, which considered both the hydrokinetic and the chaotic properties of the blast furnace ironmaking process; and great emphasis was put on its mechanism. The new model took the high complexity of the blast furnace as well as the effects of main parameters of the model into account, and the predicted results were in very good agreement with actual data.

A new kind of nonlinear fractional-order chaotic phenomenon in coupled systems： coexistence of anti-phase and complete synchronization

In this paper, we have found a kind of interesting nonlinear phenomenon hybrid synchronization in linearly coupled fractional-order chaotic systems. This new synchronization mechanism, i.e., part of state variables are anti- phase synchronized and part completely synchronized, can be achieved using a single linear controller with only one drive variable. Based on the stability theory of the fractional-order system, we investigated the possible existence of this new synchronization mechanism. Moreover, a helpful theorem, serving as a determinant for the gain of the controller, is also presented. Solutions of coupled systems are obtained numerically by an improved Adams Bashforth-Moulton algorithm. To support our theoretical analysis, simulation results are given.

多策略改进MPA算法与HKELM的变压器故障辨识

为解决目前变压器故障诊断精度低的问题,提出一种多策略改进海洋捕食者算法(MPA)与混合核极限学习机(HKELM)的变压器故障辨识方法。首先通过核主成分分析法(KPCA)对高维线性不可分的变压器故障数据进行降维,获取特征支持数据;然后通过伯努利混沌映射、改进阶段转换判据、最佳候选者等策略综合改进MPA,加强全局开发能力;最后使用改进的IMPA算法对HKELM的参数寻优,构建变压器故障诊断模型。为验证模型有效性,分析比较常用算法优化的HKELM的4种变压器故障诊断模型。其中IMPA-HKELM的诊断精度为94.7%,相比于另外3种基础算法优化的模型,诊断精度分别提升了5.4%、8%、10.7%。结果表明,提出模型有效提升了故障诊断的分类性能,并实现了较高的故障诊断精度。

Hopf bifurcation control of a Pan-like chaotic system

This paper is concerned with the Hopf bifurcation control of a modified Pan-like chaotic system. Based on the Routh-Hurwtiz theory and high-dimensional Hopf bifurcation theory, the existence and stability of the Hopf bifurcation depending on selected values of the system parameters are studied. The region of the stability for the Hopf bifurcation is investigated.By the hybrid control method, a nonlinear controller is designed for changing the Hopf bifurcation point and expanding the range of the stability. Discussions show that with the change of parameters of the controller, the Hopf bifurcation emerges at an expected location with predicted properties and the range of the Hopf bifurcation stability is expanded. Finally,numerical simulation is provided to confirm the analytic results.

A Hybrid TCNN Optimization Approach for the Capacity Vehicle Routing Problem

A novel approximation algorithm was proposed for the problem of finding the minimum total cost of all routes in Capacity Vehicle Routing Problem (CVRP). CVRP can be partitioned into three parts: the selection of vehicles among the available vehicles, the initial routing of the selected fleet and the routing optimization. Fuzzy C-means (FCM) can group the customers with close Euclidean distance into the same vehicle according to the principle of similar feature partition. Transiently chaotic neural network (TCNN) combines local search and global search, possessing high search efficiency. It will solve the routes to near optimality. A simple tabu search (TS) procedure can improve the routes to more optimality. The computations on benchmark problems and comparisons with other results in literatures show that the proposed algorithm is a viable and effective approach for CVRP.

螺旋探索与自适应混合变异的麻雀搜索算法

针对麻雀搜索算法(SSA)收敛速度慢,易陷入局部最优的问题,提出一种螺旋探索与自适应混合变异的麻雀搜索算法(SHSSA).首先,采用一种无限次折叠的ICMIC混沌初始化种群,增加种群多样性和遍历性,为全局寻优奠定基础;其次,融入一种螺旋探索策略,增强发现者探索未知区域的能力,提高算法的全局搜索性能;然后,提出一种基于精英差分和随机反向的混合变异策略,加快算法收敛速度,改善算法跳出局部最优的能力.基于12个基准测试函数的仿真结果表明,SHSSA与其余3种算法及2种改进的麻雀搜索算法相比,收敛速度更快、寻优精度更高,稳定性更强.最后,将SHSSA应用于多阈值图像分割中,实验结果表明,相较于基本SSA算法,SHSSA的分割速度和分割精度均得到了提升.

Synchronization of stochastically hybrid coupled neural networks with coupling discrete and distributed time-varying delays

A general model of linearly stochastically coupled identical connected neural networks with hybrid coupling is proposed, which is composed of constant coupling, coupling discrete time-varying delay and coupling distributed timevarying delay. All the coupling terms are subjected to stochastic disturbances described in terms of Brownian motion, which reflects a more realistic dynamical behaviour of coupled systems in practice. Based on a simple adaptive feedback controller and stochastic stability theory, several sufficient criteria are presented to ensure the synchronization of linearly stochastically coupled complex networks with coupling mixed time-varying delays. Finally, numerical simulations illustrated by scale-free complex networks verify the effectiveness of the proposed controllers.

改进的蝗虫优化算法及其应用

针对蝗虫优化算法(GOA)收敛精度不高、易陷入局部最优等问题,提出一种非线性自适应模拟退火的蝗虫优化算法(SA-NGOA)。利用非线性自适应更新GOA的关键参数,更好地协调算法的全局探索和局部开发;利用模拟退火算法,以一定概率接收GOA的劣势解,提高算法的收敛精度。实验结果表明,SA-NGOA算法具有良好的优化性能。同时,将SA-NGOA算法用于扩展同步参数观测器(ESPO)参数优化,其结果表明,该算法优化后的ESPO具有更快的辨识速度和更稳定的精度。

径向基函数-稀疏多项式混沌展开混合代理模型可靠性分析方法

为解决现有代理模型在可靠性分析中存在的普适性差、分析精度低的问题,提出一种融合径向基函数(Radial Basis Function,RBF)和稀疏多项式混沌(Sparse Polynomial Chaotic Expansion,SPCE)展开的混合代理模型,实现功能函数的快速准确预示,从而提高可靠性分析的工程适用性和计算精度。采用正交匹配追踪技术求解多项式混沌(Polynomial Chaotic Expansion,PCE)展开中的重要项,获得SPCE展开模型,并将其增广到RBF代理模型中,形成RBF-SPCE展开混合代理模型,提高代理模型的预测精度,进而结合蒙特卡洛模拟(Monte Carlo Simulation,MCS)方法开展复杂结构的可靠性分析。三个数值算例对比了所提方法与传统RBF方法及增广RBF方法的具体差异。结果表明,所提方法对结构可靠性分析具有更高的精度和效率。最后,汽车侧面碰撞的工程算例说明所提方法对复杂问题具有良好的工程适用性。