用噪声检测算法改进理想低通滤波器

针对图像去噪算法存在滤除噪声与保留图像边缘细节之间的矛盾,提出了一种使用基于分数阶微分梯度的随机噪声检测算法来提高理想低通滤波器的去噪性能的方法。首先,使用不同方向的分数阶微分梯度模板与含噪声图像进行卷积,计算出图像在不同方向上的分数阶微分梯度;然后,依据预先设定的阈值获得不同方向的分数阶微分梯度检测图,将在所有选定方向上梯度都发生跳变的像素点判定为噪声点;最后,只对图像中被检测出的噪声点用理想低通滤波器进行滤波,可使图像在去除噪声和保留图像细节两方面同时获得较优的效果。实验结果表明,所提算法不仅可以获得更好的视觉效果,而且去噪后图像的峰值性噪比(PSNR)表明去噪后的图像更接近原始图像,使用理想低通滤波器获得的最大PSNR为29.0893dB,所提算法获得的最PSNR为34.7027dB。将分数阶微积分用于图像去噪,为提高图像去噪性能提供了一个新的研究方向。     

Minimizing harmonic distortion in power system with optimal design of hybrid active power filter using differential evolution

Hybrid active power filter (HAPF) is an advanced form of harmonic filter combining advantages of both active and passive filters. In HAPF, selection of active filter gain, passive inductive and capacitive reactances, while satisfying system constraints on individual and overall voltage and current harmonic distortion levels, is the main challenge. To optimize HAPF parameters, this paper proposes an approach based on differential evolution (DE) algorithm called L-SHADE. SHADE is the success history based parameter adaptation technique of DE optimization process for a constrained, multimodal non-linear objective function. L-SHADE improves the performance of SHADE with linearly reducing the population size in successive generations. The study herein considers two frequently used topologies of HAPF for parameter estimation. A single objective function consisting of both total voltage harmonic distortion (VTHD) and total current harmonic distortion (ITHD) is formulated and finally harmonic pollution (HP) is minimized in a system comprising of both non-linear source and non-linear loads. Several case studies of a selected industrial plant are performed. The output results of L-SHADE algorithm are compared with a similar past study and also with other well-known evolutionary algorithms.     

疯狂蝙蝠算法的低通FIR滤波器设计

针对处理滤波器设计问题,蝙蝠算法（BA）很容易陷入早熟收敛,提出改进的疯狂蝙蝠算法（CBA）旨在设计低通有限脉冲响应（FIR）滤波器。首先,在频率更新中引入两个随机数来控制全局与局部的平衡;其次,在标准蝙蝠算法中引入疯狂因子,使得蝙蝠算法以一定疯狂概率维持其多样性;最后,在局部搜索时,对算法的响度和脉冲发射率进行动态修正,便于精细搜索。将CBA与其他算法进行比较,仿真结果表明,疯狂蝙蝠算法在应用实例中优于其他算法,且能够有效、稳定用于低通FIR滤波器设计。     

Adaptive differential evolution algorithm with novel mutation strategies in multiple sub-populations

Differential evolution (DE) algorithm has been shown to be a very effective and efficient approach for solving global numerical optimization problems, which attracts a great attention of scientific researchers. Generally, most of DE algorithms only evolve one population by using certain kind of DE operators. However, as observed in nature, the working efficiency can be improved by using the concept of work specialization, in which the entire group should be divided into several sub-groups that are responsible for different tasks according to their capabilities. Inspired by this phenomenon, a novel adaptive multiple sub-populations based DE algorithm is designed in this paper, named MPADE, in which the parent population is split into three sub-populations based on the fitness values and then three novel DE strategies are respectively performed to take on the responsibility for either exploitation or exploration. Furthermore, a simple yet effective adaptive approach is designed for parameter adjustment in the three DE strategies and a replacement strategy is put forward to fully exploit the useful information from the trial vectors and target vectors, which enhance the optimization performance. In order to validate the effectiveness of MPADE, it is tested on 55 benchmark functions and 15 real world problems. When compared with other DE variants, MPADE performs better in most of benchmark problems and real-world problems. Moreover, the impacts of the MPADE components and their parameter sensitivity are also analyzed experimentally.     

正交差分演化算法在工程优化设计中的应用

提出一种基于正交设计的快速差分演化算法,并把它应用于工程优化设计中。新算法在保留传统差分演化算法简单、有效等特性的同时,还具有以下一些特点：（1）引入一种基于正交设计的杂交算子,并结合约束统计优生法来产生最好子个体;（2）提出一种简单的多样性规则,以处理约束条件;（3）简化基本差分演化算法的缩放因子,尽量减少算法的控制参数,方便工程人员的使用。通过对2个工程优化实例进行实验,并与其他算法的结果作比较,其结果表明,新算法在解的精度、稳定性、收敛性和收敛速度上表现出很好的性能,并且对所优化的问题没有特殊的要求,具有很好的普适性。     

基于多变异策略的自适应差分进化算法

为了克服差分进化算法寻优精度低、收敛速度慢、稳定性差等不足,提出一种基于多变异策略的自适应差分进化算法（ADE-MM）。首先,在3个变异策略的选择过程中添加2个具有学习功能的扰动阈值,以提高种群多样性,扩大搜索范围;然后,根据上次迭代的成功参数自适应调整当前参数,提高寻优精度和寻优速度;最后,利用向量粒子池法和中心粒子法产生新的向量粒子,进一步提高寻优效果。使用8个函数、5种对比算法（RMDE、OLCPDE、JADE、SaDE、MDE_pBX）进行测试,且每种例子都独立执行30次。ADE-MM算法在均值和方差的比较中取得了全胜,其中在30维的情况下取得了5个独立胜利,3个并列胜利;在50维的情况下取得了6个独立胜利,2个并列胜利;在100维的情况下全部为独立胜利。同时在Wilcoxon rank sum test、胜率和算法耗时分析中,ADE-MM算法也取得优异的表现。实验结果表明,相对于其他5种对比算法,ADE-MM算法具有更强的全局寻优能力、收敛性和稳定性。     

8阶贝塞尔低通滤波器精确设计及应用

为了进一步改善滤波器的频率响应和时延特性,在数字信号和音频信号传输中,整个通带内具有恒定的增益和群延时,使通带内被过滤的信号波形不失真,提出了一种8阶贝塞尔低通滤波器精确设计的方法。硬件电路主要由专用滤波器芯片MAX275、单片机和数字电位器组成。滤波功能由MAX275及其外围16个电阻完成。16个电阻的精确参数值,通过单片机控制数字电位器得到。软件部分采用美国MAXIM公司的专用滤波器设计软件。通过仿真分析、试验测试及实际应用,实现了整个通带内具有恒定的增益和群延时。该滤波器结构简单,易于设计,具有推广价值。     

Correlation filter tracking algorithm based on multiple features and average peak correlation energy

Multimedia Tools and Applications - Since traditional target tracking algorithms employ artificial features, they are not robust enough to describe the appearance of a target. Therefore, it is...     

基于单形正交实验设计的差分演化算法

为了克服传统差分演化(DE)算法在求解约束优化问题时出现的收敛性慢和容易陷入早熟等缺陷,提出一种新的基于单形正交实验设计的差分演化(SO-DE)算法。该算法设计了一种结合单形交叉和正交实验设计的混合交叉算子来提高差分演化算法的搜索能力;同时采用了一种改进的个体优劣比较准则对种群个体进行比较和选择。这种新的混合交叉算子利用多个父代个体进行单形交叉产生多个子代个体,从两者中选择优秀个体进行正交实验设计得到下一代种群个体。改进的个体优劣比较准则对不同状态下的种群采用不同的处理方案,其目的在于能够有效地权衡目标函数值和约束违反量之间的关系,从而选择优秀个体进入下一代种群。通过对13个标准测试函数和2个工程设计问题进行仿真实验,实验结果表明SO-DE算法求解的精度和标准方差都要优于HEAA算法和COEA/OED算法。SO-DE算法具有更高的精度以及更好的稳定性。     

An efficient multiobjective differential evolution algorithm for engineering design

Solving engineering design and resources optimization via multiobjective evolutionary algorithms (MOEAs) has attracted much attention in the last few years. In this paper, an efficient multiobjective differential evolution algorithm is presented for engineering design. Our proposed approach adopts the orthogonal design method with quantization technique to generate the initial archive and evolutionary population. An archive (or secondary population) is employed to keep the nondominated solutions found and it is updated by a new relaxed form of Pareto dominance, called Pareto-adaptive ϵ-dominance (paϵ-dominance), at each generation. In addition, in order to guarantee to be the best performance produced, we propose a new hybrid selection mechanism to allow the archive solutions to take part in the generating process. To handle the constraints, a new constraint-handling method is employed, which does not need any parameters to be tuned for constraint handling. The proposed approach is tested on seven benchmark constrained problems to illustrate the capabilities of the algorithm in handling mathematically complex problems. Furthermore, four well-studied engineering design optimization problems are solved to illustrate the efficiency and applicability of the algorithm for multiobjective design optimization. Compared with Nondominated Sorting Genetic Algorithm II, one of the best MOEAs available at present, the results demonstrate that our approach is found to be statistically competitive. Moreover, the proposed approach is very efficient and is capable of yielding a wide spread of solutions with good coverage and convergence to true Pareto-optimal fronts.     

基于共轭梯度法的反馈差分进化混合算法及其在弹簧设计中的应用

分析了差分进化算法多种变异方式的特点以及每种变异方式所适应的搜索状态,建立了一条能够让种群根据自身的搜索环境来动态选择变异方式的反馈回路,使个体能够自学习、自调节地高效搜索。在每一代的最优个体邻域内,采用共轭梯度法确定最佳的共轭搜索方向,向量能够在最优解邻域内进行细致的局部搜索。根据混合算法的子代更新形式,从理论上证明了种群能够以概率1的方式收敛到全局最优解。与其它进化算法的对比实验结果表明,本文的差分进化算法有效提高了benchmark函数的最优值精度,加快了收敛速度。在弹簧设计问题中,利用改进的差分进化混合算法得到了较好的结构参数。     

改进差分进化策略在多峰值函数优化中的应用

针对差分演化算法与进化策略算法中所存在的不足,将模拟退火算子引入到差分演化算法的变异操作中,这样有助于在进化前期进行全局搜索,后期进行局部搜索;在标准进化策略的基础上,加入差分变异操作,提出了一种新的差分进化策略双重变异算法。通过测试算例可看出,该方法在多峰值函数优化问题中,具有求解精度较高,收敛速度较快等特点。     

A hybrid differential evolution algorithm for multiple container loading problem with heterogeneous containers

We consider a multiple container loading problem, commonly known as the three-dimensional bin packing problem (3D-BPP), which deals with maximizing container space utilization while the containers available for packing are heterogeneous, i.e., varying in size. The problem has wide applications in cargo transportation, warehouse management, medical packaging, and so on. We develop a differential evolution (DE) algorithm hybridized with a novel packing heuristic strategy, best-match-first (BMF), which generates a compact packing solution based on a given box packing sequence and a container loading sequence. The effectiveness of the proposed algorithm is evaluated on a set of industrial instances and randomly generated instances. The results show that the proposed algorithm outperforms existing solution approaches in terms of solution quality.     

Two-dimensional fractional-order digital differentiator design by using differential evolution algorithm

Designing a fractional-order digital differentiator often requires considerably complex mathematical operations and numerical approximations. Thus this paper will propose a simple method to achieve the fractional-order digital differentiator design, particularly for two-dimensional fractional-order differentiators. A two-dimensional finite impulse response (FIR) digital filter structure is utilized and designed so that its corresponding magnitude response can satisfy that of a desired fractional-order differentiator of two variables. The algorithm used to design such two-dimensional digital differentiator is the differential evolution (DE), which is one of evolutionary computations and has excellent searching capacity. The efficiency of the proposed scheme can be confirmed by some illustrative examples.     

带惯性变异与正交设计的差分进化改进算法

针对目前差分进化算法收敛速度慢,易出现早熟的问题,提出一种新的带惯性变异与正交设计的差分进化改进算法。在经典差分进化算法的基础上,对每一代群体中优于前一代的个体执行惯性变异,寻求发现更优个体,在每一代群体更新结束后,对群体中最优个体在其局部邻域内使用正交设计方法进行搜索,加快发现最优解的速度。通过对7个常用的基准测试函数进行测试,结果表明提出的算法在求解精度、收敛速度、稳定性和扩展性等方面均有很好的表现,明显优于经典差分进化算法和目前常见的差分进化改进算法。     

Feature enhancement of medical images using morphology-based homomorphic filter and differential evolution algorithm

In this paper, we present a new morphology-based homomorphic filtering technique for feature enhancement in medical images. The proposed method is based on decomposing an image into morphological subbands. The homomorphic filtering is performed using the morphological subbands. The differential evolution algorithm is applied to find an optimal gain and structuring element for each subband. Simulations show that the proposed filter improves the contrast of the features in medical images.     

Design of multipurpose digital FIR double-band filter using hybrid firefly differential evolution algorithm

Signal filtering can be treated as one of the basic requisite of communication networks. Design of an appropriate digital filter demands such filter coefficients that will create the desired frequency response with tolerable amount of ripples in the stop band(s) and pass band(s) along with high attenuation in the stop band(s). Now-a-days, artificial evolutionary methods are employed in the modern digital filter design due to lots of advantages over typical methods. In this paper, multipurpose digital linear phase double band filter (LPDBF) is designed proposing a hybrid meta-heuristic technique called hybrid firefly differential evolution (HFDE) algorithm. Generally these filters are required in different specific modern digital system networks for the simultaneous processing of signals present in two or three different channels. The proposed HFDE is an efficient evolutionary hybrid technique and is modelled considering both the optimization advantages of improved differential evolution (IDE) and firefly techniques. The global searching capability of IDE technique is strengthened by improved firefly movement. The performance of the proposed HFDE method of LPDBF design is contrasted with few popular optimal methods of design.     

Digital FIR filter design using fitness based hybrid adaptive differential evolution with particle swarm optimization

This paper presents an efficient way of designing linear phase finite impulse response (FIR) low pass and high pass filters using a novel algorithm ADEPSO. ADEPSO is hybrid of fitness based adaptive differential evolution (ADE) and particle swarm optimization (PSO). DE is a simple and robust evolutionary algorithm but sometimes causes instability problem; PSO is also a simple, population based robust evolutionary algorithm but has the problem of sub-optimality. ADEPSO has overcome the above individual disadvantages faced by both the algorithms and is used for the design of linear phase low pass and high pass FIR filters. The simulation results show that the ADEPSO outperforms PSO, ADE, and DE in combination with PSO not only in magnitude response but also in the convergence speed and thus proves itself to be a promising candidate for designing the FIR filters.     

Optimum design of prestressed concrete beams using constrained differential evolution algorithm

This paper is concerned with the cost minimization of prestressed concrete beams using a special differential evolution-based technique. The optimum design is posed as single-objective optimization problem in presence of constraints formulated in accordance with the current European building code. The design variables include geometrical dimensions that define the shape of the cross section and the amount of prestressing steel. A special (μ?+?λ)-constrained differential evolution method is performed in order to solve the optimization problem. Its search mechanism depends on several mutation strategies whereas an archiving-based adaptive tradeoff model is in charge of selecting a specific constraint-handling technique. Finally, numerical examples are included to illustrate the application of the presented approach.     

参数适应性分布式差分进化算法

提出一种适应性分布式差分进化算法.将初始种群分为多个子种群,并设计子种群间的迁移机制,当满足迁移条件时,根据冯?诺依曼拓扑结构,子种群内的优秀个体代替其邻域的较差个体,使得整个种群实现信息共享.同时,根据个体适应值变化情况,对每一个体分配不同的缩放因子?和交叉率CR,提出?和CR的适应性策略.实验结果表明,所提出算法有利于对解空间进行广泛探索,避免算法陷入早熟收敛,能够搜索到性能较好的解.