基于收敛速度和多样性的多目标粒子群种群规模优化设计

针对多目标粒子群优化算法种群规模难以确定的问题,文中提出了一种基于收敛速度和多样性的多目标粒子群优化（Convergence speed and Diversity-based Multi-Objective Particle Swarm Optimization,CD-MOPSO）算法.首先,利用优化过程的收敛速度和多样性指标构造种群规模适应度函数,完成了种群规模与优化性能关系的描述;其次,基于适应度函数设计了一种种群规模自适应调整方法,实现了种群规模的动态调整;最后,将提出的CD-MOPSO在基准优化问题ZDT上测试并应用于城市管网优化,实验结果显示CD-MOPSO能够根据求解问题自动调整种群规模,与NSGA-Ⅱ、MOPSO、SPEA2和EMDS-MOPSO相比具有更快的收敛速度和更好的优化结果.     

免疫遗传算法及认知无线电参数优化决策

根据感知的频谱环境变化及时优化并调整无线电参数是认知无线电的关键技术之一,也是一个复杂的非线性多目标优化决策问题。遗传算法是最适合优化问题的,但当遗传算法应用于优化问题时存在过早收敛问题。提出了基于遗传算法和人工免疫系统相结合的免疫遗传算法（IGA）来克服以上问题。由于在GA算法中引入了免疫系统中抗体和抗原的概念并在每一次迭代中丢弃亲和力较大的抗体,有效地防止了GA中过早收敛现象。最后,用免疫遗传算法来解决认知无线电的参数优化问题。仿真结果表明,免疫遗传算法可以迅速达到最优决策。     

Differentiated Meta-PSO Methods for Array Optimization

The particle swarm optimization (PSO) method has been successfully applied to different electromagnetic optimization problems. Because of the complexity of this kind of problems, the associated cost function is in general computationally expensive. A fast convergence of the optimization algorithm is hence required to attain results in short time. Here few variations over the standard algorithm, referred to as differentiated meta-PSO, aimed to enhance the global search capability, and to improve the algorithm convergence, are introduced. In order to verify their effectiveness the different techniques have been first applied to benchmark test functions and then used for the optimization of a planar array.     

精英反向黄金正弦鲸鱼算法及其工程优化研究

针对鲸鱼优化算法（Whale Optimization Algorithm,WOA）存在的收敛速度慢、寻优稳定性不足等问题,本文提出了精英反向学习的黄金正弦鲸鱼优化算法（Elite Opposition-Based Golden-Sine Whale Optimization Algorithm,EGolden-SWOA）.利用精英反向学习策略提高种群的多样性和质量可以有效提升算法的收敛速度,同时引入黄金分割数优化WOA的寻优方式,从而协调算法的全局探索与局部开发能力.对20个单模态和多模态测试函数进行寻优实验,并与RLPSO（Reverse-learning and Local-learning Particle Swarm Optimization）、IWOA（Improved Whale Optimization Algorithm based on nonlinear convergence factor）等多个算法进行对比,实验结果表明EGolden-SWOA具有更好的寻优精度和稳定性.进一步对EGolden-SWOA进行求解大规模问题的实验,实验结果表明EGolden-SWOA可以有效解决大规模优化问题.最后将EGolden-SWOA应用于压力容器和蝶形弹簧设计优化问题,结果表明EGolden-SWOA在工程优化方面的性能优于RCSA（Rough Crow Search Algorithm）、CPSO（Co-evolutionary Particle Swarm Optimization）等改进算法,可以有效运用于实际工程优化问题.     

区域分割的自适应变异粒子群算法

为了提高粒子群算法（PSO）的收敛性及多样性,提出一种基于区域分割的自适应变异粒子群算法（RSVPSO）.算法采用区域分割的思想,利用粒子间信息交叉,使粒子搜索区间快速缩小;同时在迭代后期与自适应变异策略相结合,提高粒子跳出局部最优陷阱的能力和增强粒子多样性,达到寻优的目的.将所提出的算法应用于8个测试函数,并与精英免疫克隆选择的协同进化粒子群等算法进行比较,结果表明,新算法在收敛速度、搜索精度及寻优效率等方面有较大提高.     

基于SVM的二次下降有效集算法

针对现有的有效集方法应用到支持向量机(support vector machine,SVM)优化问题时收敛速度较慢的问题,提出了一种基于二次下降法和推测赋值法的有效集算法.该算法在每次迭代过程中利用映射因子将迭代向量值限制在优化问题的不等式约束中,并通过调整步长使目标优化问题的函数值较传统的有效集算法进一步下降.由于函...     

Enhancing the Convergence Speed of Space Mapping Technique in Cylinder Conformal Antennas Optimization

Space mapping (SM) technique is applied in conformal antenna design. The main idea of this technique is to map the coarse model of a planar layer structure microstip antenna to fine structure of a conformal antenna including platform through space mapping. This technique is very suitable for conformal antenna optimization where long computational time is required to achieve an accurate solution. As the convergence speed of this technique is related to the response functions, some response functions are researching for accelerating the optimization. Two examples are studied to validate the advantages of the feasible response functions for accelerating the convergence speed of SM technique.     

An efficient vector quantizer providing globally optimal solutions

This paper presents a new approach in vector quantization that is designed for clustering or source coding. It incorporates both the capability of fast convergence from a monotonically descending algorithm and provides a globally optimal solution by a random optimization technique. Thus, it benefits from properties of deterministic and stochastic search. Comprehensive experiments demonstrate that the new algorithm actually assimilated the advantages of the both components. It may be therefore regarded as an accelerated global optimization method whose convergence is theoretically proved. According to the complexity of the quantization problem, the convergence rate is shown (numerically) to approach that of a coordinate descent algorithm, which is an iterative updating of a single codevector at a time (generalized Lloyd algorithm GLA, i.e., K-means). The new method is investigated and compared with GLA and a globally operating stochastic relaxation technique. The comparison was made with respect to quality, reliability, and efficiency and applied to four categories of data: an easy to grasp example, patterns derived from the EEG, Gauss-Markov, and image sources     

Convergence enhancement for the vector finite element modeling of microwaves and antennas via differential evolution

A global optimization technique, based on the differential evolution algorithm is introduced to trace the optimal higher-order Whitney element, with respect to convergence, among a very wide class of parameter-dependent finite elements. Any tetrahedral element of this class provides exactly the same solution, but the convergence of the iterative solution method may significantly vary. Through the proposed comprehensive optimization procedure, the existence of optimal vector finite elements is revealed. The proposed method has been applied to obtain second-order elements utilized in three-dimensional microwave and antenna simulations.     

最优化方法在BP算法中的应用研究

从非线性无约束问题的最优化方法出发,讨论了BP算法及其改进算法的数学本质和其中蕴含的最优化思想,总结了其中的数学思想和基本规律,为BP算法中收敛速度的改进指出一个科学的研究思路,最后编程实现一个传统的改进算法,并应用到异或问题中验证了优化思想及所采用的启发式信息对BP算法收敛速度的显著提高.     

粒子群优化BP-PID的矿井提升机调速系统

传统PID控制器在矿井提升机变频调速系统应用中,由于控制参数固定且不易整定,导致电机转速超调大、电磁转矩和转子磁链脉动大,进而出现矿井提升机调速系统控制效果差的问题。针对这一问题,文中提出一种改进粒子群优化BP神经网络PID控制器的算法。由于BP神经网络算法存在收敛速度慢和极易陷入局部最优的缺点,现将粒子群算法收敛速度快和全局最优特性与神经网络结合,并通过设计神经网络收敛系数进一步加快收敛速度。仿真结果表明,粒子群优化的神经网络控制效果比神经网络好,且效果明显优于传统PID控制器;相较于神经网络PID控制器,矿井提升机转速调节系统稳速调节速度明显提高;与传统PID控制器相比,电机电磁转矩和转子磁链脉动明显降低,具有较强的稳定性和鲁棒性。     

一种改进的混沌粒子群优化算法

粒子群优化算法（PSO）自提出以来,已经被广泛地应用于求解各类复杂的优化问题,过去对粒子群算法的研究主要集中在融入新的优化方法或对其相关参数进行调整,但这样只会使得PSO更加复杂.针对这一问题,文中提出一种改进的混沌粒子群优化算法（ICPSO）,ICPSO从粒子群优化算法的时间与寻优实时角度出发（即在较短的时间内获得较好的解）,对粒子速度更新算子进行了简化,每隔一定代数后,在最优解邻近区域引入混沌扰动以避免种群陷入局部最优解.数值实验结果表明：提出的算法相对于文献给出的PSO改进算法,不仅能够获得较好的最优解,而且还具有较快的收敛速度和较好的稳定性.     

基于天牛须算法的粒子群算法在PID参数整定上的应用

PSO虽然被广泛应用于包含PID参数整定等各种寻优问题中,但是传统粒子群算法在某些场合收敛速度慢且较容易陷入局部最优值。针对这些问题,文中提出一种将新型高效BAS融合进PSO算法的全局寻优过程,该方法可以更好地跳出局部最优点。同时,由于BAS算法为单一个体的算法,易因为早熟收敛陷入局部最优,故将BAS和传统的PSO结合也增强了BAS的丰富度。在Schaffer函数进行的20次独立测试显示,该算法相对于传统PSO和BAS取得了较好的寻优结果。最后,将算法应用到不稳定对象的PID参数寻优中,结果显示相对于PSO和改进PSO算法,新算法下的ts、tr、IAE、ISE等各项指标均得到了提高。     

Iterative reweighted least-squares design of FIR filters

Develops a new iterative reweighted least squares algorithm for the design of optimal L_p approximation FIR filters. The algorithm combines a variable p technique with a Newton's method to give excellent robust initial convergence and quadratic final convergence. Details of the convergence properties when applied to the L_p optimization problem are given. The primary purpose of L_p approximation for filter design is to allow design with different error criteria in pass and stopband and to design constrained L₂ approximation filters. The new method can also be applied to the complex Chebyshev approximation problem and to the design of 2D FIR filters     

改进型免疫量子粒子群算法求解TSP问题

为了克服粒子群优化算法早熟收敛以及量子粒子在进化过程中缺乏很好的方向指导的问题,受生物免疫系统与量子计算思想的启发,采用了量子技术以及免疫机制,把免疫思想应用到量子粒子群算法,提出了免疫量子粒子群算法.可以指导粒子朝着更优方向进化,提高了量子粒子群的收敛速度和寻优能力,实验结果表明,仿真实验表明所提算法具有较好的性能,在求解TSP问题时收敛速度和寻优能力都取得了更好的效果.     

基于智能反射面辅助的无人机中继系统安全通信方法

为了提高无人机中继系统的安全通信性能,解决无线信道受障碍物遮挡问题,该文提出一种基于智能反射面(IRS)辅助的无人机(UAV)中继系统安全通信方法。在所提方法中,通过联合优化UAV的位置、基站波束成形和IRS相移,最大化系统的最小保密速率。为了解决这个复杂的非凸优化问题,该文将原问题分解为UAV位置优化子问题、波束成形和IRS相移优化两个子问题。使用1阶泰勒展开处理优化问题中的非凸项,然后提出一种交替优化的算法进行求解。仿真结果表明该文提出的算法能提高系统的最小保密速率,并且具有良好的收敛性。     

基于改进型蚁群算法的阵列天线综合

将蚁群算法应用于优化阵元电流幅度,以实现对阵列天线方向图的综合。并针对传统蚁群算法难以解决电流激励幅度这样的连续变量优化和早熟收敛的问题,提出了一种改进型蚁群算法。该改进型蚁群算法对变量采用不整编码并在寻优过程中采用邻域优化方法,使其既可以对连续变量寻优,又同时改善了算法的优化速度和收敛精度。计算结果表明:该改进型蚁群算法在改变阵元激励幅度的方向图综合问题上取得比相关文献更好的结果。     

Complex Adaptive ICA Employing the Conjugate Gradient Technique for Signal Separation in Time-Varying Flat Fading Channels

The conjugate gradient method is a prominent technique for solving systems of linear equations and unconstrained optimization problems, including adaptive filtering. Since it is an iterative method, it can be particularly applied to solve sparse systems which are too large to be handled by direct methods. The main advantage of the conjugate gradient method is that it employs orthogonal search directions with optimal steps along each direction to arrive at the solution. As a result, it has a much faster convergence speed than the steepest descent method, which often takes steps in the same direction as earlier steps. Furthermore, it has lower computational complexity than Newton’s iteration approach. This unique tradeoff between convergence speed and computational complexity gives the conjugate gradient method desirable properties for application in numerous mathematical optimization problems. In this paper, the conjugate gradient principle is applied to complex adaptive independent component analysis (ICA) for maximization of the kurtosis function, to achieve separation of complex-valued signals. The proposed technique is called the complex block conjugate independent component analysis (CBC-ICA) algorithm. The CBC-ICA derives independent conjugate gradient search directions for the real and imaginary components of the complex coefficients of the adaptive system employed for signal separation. In addition, along each conjugate direction an optimal update is generated separately for the real and imaginary components using the Taylor series approximation. Simulation results confirm that in dynamic flat fading channel conditions, the CBC-ICA demonstrates excellent convergence speed and accuracy, even for large processing block sizes.     

基于免疫算法的IIR数字滤波器优化与实现

由于IIR数字滤波器设计实质上是一个非线性高维复杂函数优化问题,文中提出基于具有全局搜索能力强,收敛速度快特点的免疫算法实现IIR数字滤波器优化设计的新方法,给出了IIR滤波器优化设计的数学模型,描述了应用免疫算法优化设计IIR数字滤波器的具体实现步骤。通过低通和高通IIR数字滤波器设计的仿真结果表明方法的有效性和高效性。     

基于改进遗传算法的多目标JSP调度研究

针对多目标车间作业调度问题(JSP),提出了一种混合遗传算法,将多目标遗传算法得出的初步优化结果作为粒子群算法的初始粒子,利用粒子群算法强化局部搜索,加快收敛速度,改善了简单遗传算法局部搜索能力差、迭代效率低的问题.仿真结果表明了该算法对JSP调度的良好效果.