A self-adaptive differential evolution algorithm for continuous optimization problems

This paper proposes a new self-adaptive differential evolution algorithm (DE) for continuous optimization problems. The proposed self-adaptive differential evolution algorithm extends the concept of the DE/current-to-best/1 mutation strategy to allow the adaptation of the mutation parameters. The control parameters in the mutation operation are gradually self-adapted according to the feedback from the evolutionary search. Moreover, the proposed differential evolution algorithm also consists of a new local search based on the krill herd algorithm. In this study, the proposed algorithm has been evaluated and compared with the traditional DE algorithm and two other adaptive DE algorithms. The experimental results on 21 benchmark problems show that the proposed algorithm is very effective in solving complex optimization problems.     

广义模糊熵图像阈值分割参数选取的ADE方法

针对广义模糊熵图像阈值分割参数不能自动选取,提出自适应差分进化（Adaptive Differential Evolution,ADE）的广义模糊熵图像阈值分割方法。利用自适应差分进化算法作为优化工具来选取广义模糊熵阈值分割所需要的最佳参数,引入自适应变异算子和提出交叉概率自适应函数对优化过程进行控制,通过把参数带入广义模糊熵的补函数得到图像的阈值,进而得到图像最优分割。为验证其有效性与可行性,分别同基本图像质量评价准则的模糊熵图像阈值分割算法和粒子群优化广义模糊熵图像阈值分割算法相比较,实验表明,针对不同细节的图片,该算法所得分割结果多数情况下背景信息更少,目标信息更清晰,用时更短,分割更稳定且效果良好。     

微分进化自适应模糊C均值分割算法

模糊C均值（FCM）聚类算法分割图像时,对图像的背景噪声和聚类算法的初始值比较敏感,为了克服这个问题,进而提出了微分进化模糊[C]均值分割算法。为了避免陷入局部极值,首先使用FCM聚类初始化,接着用改进的FCM进行模糊聚类;然后进行初始化种群操作,设置微分进化DE算法的参数,计算种群中每个个体的适应值,最后对满足条件的适应值进行变异、交叉、选择操作。利用DE算法的全局搜索优化能力,有效抑制了局部极值的产生和图像的背景噪声、纹理细节对图像分割效果的影响。还克服了对初值选择敏感的问题,保证图像分割边界的完整性,是一个比较高效的方法,有效地提升了分割效果。DE算法本身具有简单,快速,鲁棒性好等优点,利用这些优点可以有效地克服FCM算法的缺点。     

Simulated evolution for timing and low power VLSI standard cell placement

This paper presents a Fuzzy Simulated Evolution algorithm for VLSI standard cell placement with the objective of minimizing power, delay and area. For this hard multiobjective combinatorial optimization problem, no known exact and efficient algorithms exist that guarantee finding a solution of specific or desirable quality. Approximation iterative heuristics such as Simulated Evolution are best suited to perform an intelligent search of the solution space. Due to the imprecise nature of design information at the placement stage the various objectives and constraints are expressed in the fuzzy domain. The search is made to evolve toward a vector of fuzzy goals. Variants of the algorithm which include adaptive bias and biasless simulated evolution are proposed and experimental results are presented. Comparison with genetic algorithm is discussed.     

基于差分文化算法的FIR数字滤波器设计

有限脉冲响应（FIR）数字滤波器的设计实质可看作是多参数优化问题。为高效实现FIR数字滤波器,将滤波器的设计转化为滤波器参数优化问题,然后提出差分文化粒子群（DC）算法在参数空间进行并行搜索以获得滤波器设计的最优参数值。提出的差分文化算法结合文化原理差分演进原理,是一种可用于实数优化的多维搜索算法。计算机仿真实验表明在设计FIR数字滤波器设计时,差分文化算法的收敛速度和性能都优于粒子群,量子粒子群以及自适应量子粒子群优化等算法,证明了该方法的有效性和优越性。     

基于自适应差异进化法的电力系统无功优化

差异进化算法（DE）是一种新的进化算法,近年来的研究和应用已经展示出很大的应用潜力,但其中的某些参数需通过试验确定,影响了实用性。提出一种自适应差异进化算法（FADE）,能使算法的控制参数粮据求解问题的不同在优化过程中自适应发生改变,并应用于无功优化问题。通过IEEE-30节点算例系统的仿真结果证明,与DE和GA算法相比,模糊差异进化算法具有很强的自适应性及通用性。     

多目标微分进化改进算法及应用

微分进化算法作为一种新型、简单、高效的并行随机优化算法,近年来在许多领域得到了应用,多目标微分进化便是其中的一种。针对传统多目标微分进化算法中微分进化控制参数不能自适应调整、算法容易出现早熟和退化的现象,采用惯性权重参数自适应调整的控制策略以及改进的拥挤距离算法对多目标微分进化进行改进,并将改进后的算法用于控制系统PID参数优化仿真试验。结果表明,改进后的多目标微分进化算法具有较好的收敛性和分布性以及较高的搜索效率。     

求解多峰目标函数的改进阴阳对算法

针对阴阳对优化算法(YYPO)在优化多峰目标函数时存在收敛速度过快和收敛精度过低等问题,提出了一种融合差分变异策略和高斯分布扰动的D向分割方法改进的阴阳对算法MYYPO。首先,MYYPO在算法的分割阶段引入了结合自适应变异因子的差分变异操作,以提高候选解的多样性并增强算法的全局探索能力。其次,利用改进的D向分割方法进行候选解的更新,提高算法面对高维目标函数的搜索能力。实验采用CEC2013进化大会中的20个测试函数对各算法的性能进行评估。实验结果表明,MYYPO在多峰函数的优化上可以获得更好的收敛精度和更好的全局搜索能力,在大多数情况下都优于标准YYPO和YYPO的其他改进算法。最后,将MYYPO应用于一个电液位置伺服控制系统的PID参数优化问题,MYYPO也获得了最好的结果。     

基于群体分布的自适应差分进化算法

差分进化算法是一种简单有效的启发式全局优化算法,但是其优化性能受差分进化策略及控制参数取值的影响较大,不合适的策略和参数容易导致算法早熟收敛。因此,针对差分进化算法搜索过程中变异策略和控制参数的选择问题,文中提出了一种基于群体分布的自适应差分进化算法(Population Distribution-based Self-adaptive Differential Evolution,PDSDE)。首先,设计适应因子以衡量当前种群的分布情况,进而实现算法所处进化阶段的自适应判断;然后,根据不同进化阶段的特点,设计阶段特定的变异策略和控制参数,并设计自适应机制以实现算法策略和参数的动态调整,从而平衡算法的全局探测和局部搜索能力,以达到提高算法搜索效率的目的;最后,将所提算法与6种主流改进算法进行比较。15个典型测试函数的数值实验表明,所提算法在平均函数评价次数、求解精度、收敛速度等指标的评价优于文中给出的6种主流改进算法,因此可以证明所提算法的计算代价、优化性能和收敛性能更具优势。     

基于模糊需求和模糊运输时间的多式联运路径优化

考虑不确定性的模糊多式联运路径优化研究, 可以在满足运输方案经济环保双重要求的同时, 增强运输方案的鲁棒性, 提高企业的抗风险能力. 本文建立了模糊需求和模糊运输时间下低碳低成本多式联运路径优化模型,针对连续型元启发式算法无法直接求解离散型组合优化模型的问题, 设计了基于优先级的通用编码方式. 在此基础上, 为进一步提高算法的求解质量, 提出了带启发式因子的特殊解码方式, 并且提出了一种带邻域搜索策略的自适应差分进化算法. 结果表明, 改进算法获得的最终方案在蒙特卡罗采样的大多数场景下满足约束, 方案稳定性强,目标值最低.     

Remote sensing image subpixel mapping based on adaptive differential evolution

In this paper, a novel subpixel mapping algorithm based on an adaptive differential evolution (DE) algorithm, namely, adaptive-DE subpixel mapping (ADESM), is developed to perform the subpixel mapping task for remote sensing images. Subpixel mapping may provide a fine-resolution map of class labels from coarser spectral unmixing fraction images, with the assumption of spatial dependence. In ADESM, to utilize DE, the subpixel mapping problem is transformed into an optimization problem by maximizing the spatial dependence index. The traditional DE algorithm is an efficient and powerful population-based stochastic global optimizer in continuous optimization problems, but it cannot be applied to the subpixel mapping problem in a discrete search space. In addition, it is not an easy task to properly set control parameters in DE. To avoid these problems, this paper utilizes an adaptive strategy without user-defined parameters, and a reversible-conversion strategy between continuous space and discrete space, to improve the classical DE algorithm. During the process of evolution, they are further improved by enhanced evolution operators, e.g., mutation, crossover, repair, exchange, insertion, and an effective local search to generate new candidate solutions. Experimental results using different types of remote images show that the ADESM algorithm consistently outperforms the previous subpixel mapping algorithms in all the experiments. Based on sensitivity analysis, ADESM, with its self-adaptive control parameter setting, is better than, or at least comparable to, the standard DE algorithm, when considering the accuracy of subpixel mapping, and hence provides an effective new approach to subpixel mapping for remote sensing imagery.     

基于改进量子粒子群算法的NCS模糊控制器参数优化

针对网络化控制系统中模糊控制器的量化因子和比例因子采用传统经验方法难以整定的问题, 提出了一种改进量子粒子群（IQPSO）算法对模糊控制器量化因子和比例因子进行优化。该方法将ABC算法中的搜索算子作为变异算子引入到QPSO算法中, 使得IQPSO算法较好地克服了QPSO算法保持种群多样性差容易早熟收敛的缺陷, 并以ITAE指标作为IQPSO算法的适应度函数对模糊控制器进行优化。典型工业过程仿真结果表明, IQPSO优化的模糊控制器具有比PID控制器和标准QPSO优化的模糊控制器更好的控制性能和适用性。     

Automatically extracting T–S fuzzy models using cooperative random learning particle swarm optimization

This paper proposes a methodology for automatically extracting T–S fuzzy models from data using particle swarm optimization (PSO). In the proposed method, the structures and parameters of the fuzzy models are encoded into a particle and evolve together so that the optimal structure and parameters can be achieved simultaneously. An improved version of the original PSO algorithm, the cooperative random learning particle swarm optimization (CRPSO), is put forward to enhance the performance of PSO. CRPSO employs several sub-swarms to search the space and the useful information is exchanged among them during the iteration process. Simulation results indicate that CRPSO outperforms the standard PSO algorithm, genetic algorithm (GA) and differential evolution (DE) on the functions optimization and benchmark modeling problems. Moreover, the proposed CRPSO-based method can extract accurate T–S fuzzy model with appropriate number of rules.     

基于改进遗传算法的列车运行曲线优化

传统遗传算法很早就在列车运行优化研究中得到了应用,但是由于种群中染色体进化方向的不确定性和局部搜索能力不足,导致收敛速度缓慢和求解质量低下。针对以上问题,本文提出一种改进型遗传算法,对列车运行曲线的生成进行研究。以列车运行能耗最小为优化目标,将行车安全、准点和精确停车等约束条件转化为惩罚函数,同时以工况序列为遗传个体进行求解,为加快种群收敛速度和提高解的质量,设计包含准点调整和局部搜索的种群进化方向引导机制。仿真结果表明,改进后的算法适用于多约束的列车运行优化问题,有效提升了收敛速度,优化结果相比于简单遗传算法和自适应遗传算法更加节能。     

制冷站双目标权重自适应非线性预测控制

针对传统制冷站控制系统易产生振荡, 且无法实现系统性能整体优化的问题, 本文提出一种制冷站非线性 预测控制策略, 优化目标函数设计为满足建筑冷量需求的同时, 尽可能提高系统整体能效. 为解决上述两个优化目 标之间的矛盾关系, 本文采用模糊逻辑设计了优化目标权重自适应模块, 实时求取权重因子最优解; 针对非线性系 统在线优化求解困难问题, 本文提出了基于神经网络的非线性滚动优化算法, 采用神经网络作为反馈优化控制器, 并将系统优化目标函数作为在线寻优性能指标, 结合Euler-Lagrange方法和随机梯度下降法对控制器权值和阈值进 行在线寻优, 算法计算量小, 占用存储空间适中, 便于采用低成本的现场控制器实现制冷站预测控制. 仿真实验结果 表明, 本文所提出的预测控制策略与PID控制相比, 在未加入优化目标函数权重自适应模块情况下, 系统平均能效 比提高约32.5%; 进行优化目标函数权重自适应寻优后, 系统平均能效提高约39.43%.     

Accelerating Differential Evolution Using an Adaptive Local Search

We propose a crossover-based adaptive local search (LS) operation for enhancing the performance of standard differential evolution (DE) algorithm. Incorporating LS heuristics is often very useful in designing an effective evolutionary algorithm for global optimization. However, determining a single LS length that can serve for a wide range of problems is a critical issue. We present a LS technique to solve this problem by adaptively adjusting the length of the search, using a hill-climbing heuristic. The emphasis of this paper is to demonstrate how this LS scheme can improve the performance of DE. Experimenting with a wide range of benchmark functions, we show that the proposed new version of DE, with the adaptive LS, performs better, or at least comparably, to classic DE algorithm. Performance comparisons with other LS heuristics and with some other well-known evolutionary algorithms from literature are also presented.     

Levy distributed parameter control in differential evolution for numerical optimization

Differential evolution (DE) algorithm is a population based stochastic search technique widely applied in scientific and engineering fields for global optimization over real parameter space. The performance of DE algorithm highly depends on the selection of values of the associated control parameters. Therefore, finding suitable values of control parameters is a challenging task and researchers have already proposed several adaptive and self-adaptive variants of DE. In the paper control parameters are adapted by levy distribution, named as Levy distributed DE (LdDE) which efficiently handles exploration and exploitation dilemma in the search space. In order to assure a fair comparison with existing parameter controlled DE algorithms, we apply the proposed method on number of well-known unimodal, basic and expanded multimodal and hybrid composite benchmark optimization functions having different dimensions. The empirical study shows that the proposed LdDE algorithm exhibits an overall better performance in terms of accuracy and convergence speed compared to five prominent adaptive DE algorithms.     

Optimal fuzzy controller parameters using PSO for speed control of Quasi-Z Source DC/DC converter fed drive

The conventional controller suffers from uncertain parameters and non-linear qualities of Quasi-Z Source converter. However they are computationally inefficient extending to optimize the fuzzy controller parameters, since they exhaustively search the optimal values to optimize the objective functions. To overcome this drawback, a PSO based fuzzy controller parameter optimization is presented in this paper. The PSO algorithm is used to find the optimal fuzzy parameters for minimizing the objective functions. The feasibility of the proposed PSO technique has been simulated and tested. The results are bench marked with conventional fuzzy controller and genetic algorithm for two types of DC/DC converters namely double input Z-Source converter and Quasi-Z Source converter. The results of both the DC/DC converters for several existing methods illustrate the effectiveness and robustness of the proposed algorithm.     

Item-Location Assignment Using Fuzzy Logic Guided Genetic Algorithms

In today's logistics environment, large-scale combinatorial problems will inevitably be met during industrial operations. This paper deals with a novel real-world optimization problem, called the item-location assignment problem, faced by a logistics company in Shenzhen, China. The objective of the company in this particular operation is to assign items to suitable locations such that the required sum of the total traveling time of the workers to complete all orders is minimized. A stochastic search technique called fuzzy logic guided genetic algorithms (FLGA) is proposed to solve this operational problem. In GA, a specially designed crossover operation, called a shift and uniform based multi-point (SUMP) crossover, and swap mutation are adopted. The performance of this novel crossover operation is tested and is shown to be more effective by comparing it to other crossover methods. Furthermore, the role of fuzzy logic is to dynamically adjust the crossover and mutation rates after each ten consecutive generations. In order to demonstrate the effectiveness of the FLGA and make comparisons with the FLGA through simulations, various search methods such as branch and bound, standard GA (i.e., without the guide of fuzzy logic), simulated annealing, tabu search, differential evolution, and two modified versions of differential evolution are adopted. Results show that the FLGA outperforms the other search methods in all of the three considered scenarios.      

Adaptation in differential evolution: A numerical comparison

Paper considers adaptation of control parameters in differential evolution. Adaptation by competitive setting is described and two novel variants of competitive differential evolution are proposed. Five adaptive variants of differential evolution are compared with other search algorithms on three benchmarks. One of them is the novel composition test functions, where the variants of differential evolution outperform other algorithms in 5 of 6 test functions. The NIST nonlinear regression datasets are used as the second benchmark and a subset of CEC’05 benchmark functions as the third one. The performance of adaptive differential evolution is compared with the adaptive controlled random search algorithm, tailored especially for the nonlinear-regression problems. Two of five tested variants of adaptive differential evolution are almost as reliable as the adaptive controlled random search algorithm and one of these variants converges only slightly slower than the adaptive controlled random search in nonlinear-regression problems. The results achieved in CEC’05 benchmark functions are close to the best performing algorithm. Therefore, the adaptive differential evolution is a promising tool of heuristic search for the global minimum in boundary-constrained problems.