基于改进遗传算法的PID参数优化研究

针对基本遗传算法收敛速度慢和寻优能力不足的问题,提出了一种基于实数编码的改进遗传算法.新算法中,初始种群由空间距离控制使其能够均匀分布于解空间;交叉操作采用等分组的方法,时每组内每两个个体均进行交叉,并择优选择,以扩大搜索空间:变异步长随进化代数自适应调整.将改进后的遗传算法运用于PID控制器参数优化中,通过仿真实验表明,新算法整定效果明显优于基本遗传算法,不仅解决了基本遗传算法存在的缺陷,而且提高了收敛速度与寻优精度.     

基于免疫遗传算法的雷达重复频率选择

多普勒雷达能够在较强的杂波背景中检测目标,被广泛应用,但它既存在距离模糊,又存在速度模糊,需要在巨大的解空间中选择一组重复频率解模糊。免疫遗传算法是基于免疫原理,对遗传算法的改进,它克服了遗传算法易早熟、搜索效率低、不能很好保持个体的多样性等缺点。运用基于实数编码的免疫遗传算法来选择多重中脉重复频率。实验表明该方法便于编码,比基本的遗传算法能更快更准确地找到满意解。     

一种改进的实数自适应遗传算法

研究了基于实数编码的遗传算法的改进问题．针对实数编码在搜索后期存在搜索效率低、易早熟收敛等现象．讨论了遗传算法的参数调节问题．提出一种自适应交叉概率和变异概率，既考虑了进化代数对算法的影响，又考虑到每代不同个体适应度的作用，给出一种改进的实数自适应遗传算法．最后利用3个测试函数对算法进行验证，在函数的最终值、平均运行代数、收敛概率几方面都取得了较好的结果．     

对实数编码遗传算法的改进

分析了实数编码遗传算法存在的缺陷,并在此基础上提出了几点改进方案。改进后的实数遗传算法可以很好地提高算法的搜索速度,并稳定地获得最优解。     

基于混沌量子遗传改进的模糊C均值聚类算法

针对标准FCM对噪声和初值敏感的问题,提出一种基于实数编码混沌量子遗传算法(RCQGA)的改进的加入空间信息的FCM算法。该算法在解空间内将实数染色体通过反向变换映射到量子位,采用量子位概率指导的实数交叉与混沌变异相结合的方法对实数染色体进行演化搜索。将RCQGA与结合空间邻域信息的FCM相结合,用改进的FCM算法的目标函数建立适应度函数,利用混沌量子遗传算法搜索全局最优解,代替传统FCM的基于梯度下降的迭代爬山过程,从而有效地避免了模糊C-均值聚类算法收敛到局部最优和对噪声敏感的问题,并在此基础上实现了对遥感图像的聚类分割。实验结果表明,该算法对于遥感图像显示了较好的分割效果和较强的抗噪能力。     

一种基于二次变异策略的改进型遗传算法

通过对基本遗传算法采用单点位变异和倒置变异两次变异操作进行改进,并把该算法应用到TSP问题的求解中。仿真结果表明,改进后的算法提高了种群的多样性,增强了算法的局部搜索能力,从而使最终找到的解比基本遗传算法更优。另外,二次变异的改进遗传算法对种群规模的敏感性比非二次变异的基本遗传算法更强,相同条件下当增大种群规模时,二次变异的改进算法能得到更优的解。     

基于随机基因交叉与多倍体策略的遗传算法

针对经典遗传算法的早熟及精度问题进行了研究,提出了一种基于随机基因实数交叉与多倍体策略的遗传算法。借鉴生物界中多倍体的概念,采用了实数编码并利用多倍体分别保存最优单体、保留单体及变异单体,从而组成多样性种群;选择操作采用了轮盘赌算法;交叉操作引入随机基因交叉概念。最后应用测试函数对算法进行测试,并与经典遗传算法进行了比较。仿真实验结果表明,该改进算法不仅保持了种群的多样性,有效抑制了早熟收敛,还降低了算法的复杂度,提高了搜索精度,使得算法能以较高的精度达到复杂高维度函数的全局最优。     

基于水平集的遗传算法优化的改进

现有的遗传算法大多数没有给出收敛性准则，且存在早熟收敛和收敛速度较慢的难题，为此提出一类新型遗传算法．该算法首先从被优化函数的因变量出发，引入了水平集的新概念，对每一代种群进行分类，把与目标相关的所有信息有机地结合在一起，从而提高了算法的优化速度；其次通过对变异算子进行改进，提高了种群的多样性，有效地避免了遗传算法的早熟收敛；同时还证明了变异算子能提高种群多样性以及新算法能收敛于全局最优解，最后给出了算法的收敛准则．实验表明，该算法正确有效，搜索效率与精度均优于其他方法．     

Improved genetic algorithm：GA-EO algorithm

针对基本遗传算法GA有局部搜索能力差、计算量大、对较大搜索空间适应能力差和易收敛于局部极小值等问题, 采用将极值优化EO算法与传统遗传算法相结合的方式, 对基本遗传算法进行改进, 提出了一种新的算法：GA-EO算法, 并用实验证明了新算法的有效性。     

遗传算法在0/1背包问题中的应用及研究

遗传算法作为一种优胜劣汰的自然规律,可应用于人工智能、机器学习等多个方面。本文将遗传算法应用于0/1背包问题,首先介绍简单遗传算法,通过实验数据分析遗传算法在搜索范围、收敛速度和精度等方面的不足,进而基于贪心算法、适应度函数及遗传算子,修正可行解和不可行解,逐步改进遗传算法,防止算法陷于局部最优,提高算法的全局搜索能力和收敛速度。最后通过实验数据,比较简单遗传算法和改进遗传算法的实验结果,证明改进遗传算法在0/1背包问题应用中的精确性和高效性。     

Investigation of self-organizing map for genetic algorithm

This paper describes self-organizing maps for genetic algorithm (SOM-GA) which is the combinational algorithm of a real-coded genetic algorithm (RCGA) and self-organizing map (SOM). The self-organizing maps are trained with the information of the individuals in the population. Sub-populations are defined by the help of the trained map. The RCGA is performed in the sub-populations. The use of the sub-population search algorithm improves the local search performance of the RCGA. The search performance is compared with the real-coded genetic algorithm (RCGA) in three test functions. The results show that SOM-GA can find better solutions in shorter CPU time than RCGA. Although the computational cost for training SOM is expensive, the results show that the convergence speed of SOM-GA is accelerated according to the development of SOM training.     

Gradual distributed real-coded genetic algorithms

A major problem in the use of genetic algorithms is premature convergence. One approach for dealing with this problem is the distributed genetic algorithm model. Its basic idea is to keep, in parallel, several subpopulations that are processed by genetic algorithms, with each one being independent of the others. Making distinctions between the subpopulations by applying genetic algorithms with different configurations, we obtain the so-railed heterogeneous distributed genetic algorithms. These algorithms represent a promising way for introducing a correct exploration/exploitation balance in order to avoid premature convergence and reach approximate final solutions. This paper presents the gradual distributed real-coded genetic algorithms, a type of heterogeneous distributed real-coded genetic algorithms that apply a different crossover operator to each sub-population. Experimental results show that the proposals consistently outperform sequential real-coded genetic algorithms     

Adaptive directed mutation for real-coded genetic algorithms

Adaptive directed mutation (ADM) operator, a novel, simple, and efficient real-coded genetic algorithm (RCGA) is proposed and then employed to solve complex function optimization problems. The suggested ADM operator enhances the abilities of GAs in searching global optima as well as in speeding convergence by integrating the local directional search strategy and the adaptive random search strategies. Using 41 benchmark global optimization test functions, the performance of the new algorithm is compared with five conventional mutation operators and then with six genetic algorithms (GAs) reported in literature. Results indicate that the proposed ADM-RCGA is fast, accurate, and reliable, and outperforms all the other GAs considered in the present study.     

改进的遗传算法用于氩原子簇的结构优化

目的:研究一种改进的遗传算法对氩原子簇的结构进行优化;方法：描述了一种采用实数串编码,非一致性变异和数值交叉算子改进的遗传算法,同时结合了局部搜索技术来进一步优化遗传算法得到的最佳解;结论：将改进的遗传算法用于氩原子簇（Ar)N（N＝2.14）的结构优化后,其结果表明MGALM虽算法简单,但对较小原子簇体系（N≤14）,可以得到其已知的全局最优结构。     

实数编码混沌量子遗传算法

基于量子位的混沌特性和相干特性,提出一种实数编码混沌量子遗传算法（RCQGA）．该算法在解空间内将实数染色体通过反向变换映射到量子位,采用量子位概率指导的实数交叉与混沌变异相结合的方法对实数染色体进行演化搜索．实验结果表明,RCQGA不仅可以有效避免二进制编码QGA早熟收敛的缺点,而且可以减少寻优的计算复杂度,具有收敛速度快、稳定性好、寻优能力强、精度提高容易等优点,适用于工程应用中的复杂函数优化问题．     

Real-coded chaotic quantum-inspired genetic algorithm for training of fuzzy neural networks

In this paper, a novel approach to adjusting the weightings of fuzzy neural networks using a Real-coded Chaotic Quantum-inspired genetic Algorithm (RCQGA) is proposed. Fuzzy neural networks are traditionally trained by using gradient-based methods, which may fall into local minimum during the learning process. To overcome the problems encountered by the conventional learning methods, RCQGA algorithms are adopted because of their capabilities of directed random search for global optimization. It is well known, however, that the searching speed of the conventional quantum genetic algorithms (QGA) is not satisfactory. In this paper, a real-coded chaotic quantum-inspired genetic algorithm (RCQGA) is proposed based on the chaotic and coherent characters of Q-bits. In this algorithm, real chromosomes are inversely mapped to Q-bits in the solution space. Q-bits probability-guided real cross and chaos mutation are applied to the evolution and searching of real chromosomes. Chromosomes consisting of the weightings of the fuzzy neural network are coded as an adjustable vector with real number components that are searched by the RCQGA. Simulation results have shown that faster convergence of the evolution process in searching for an optimal fuzzy neural network can be achieved. Examples of nonlinear functions approximated by using the fuzzy neural network via the RCQGA are demonstrated to illustrate the effectiveness of the proposed method.     

Comparing performances of backpropagation and genetic algorithms in the data classification

Artificial neural networks (ANN) have a wide ranging usage area in the data classification problems. Backpropagation algorithm is classical technique used in the training of the artificial neural networks. Since this algorithm has many disadvantages, the training of the neural networks has been implemented with the binary and real-coded genetic algorithms. These algorithms can be used for the solutions of the classification problems. The real-coded genetic algorithm has been compared with other training methods in the few works. It is known that the comparison of the approaches is as important as proposing a new classification approach. For this reason, in this study, a large-scale comparison of performances of the neural network training methods is examined on the data classification datasets. The experimental comparison contains different real classification data taken from the literature and a simulation study. A comparative analysis on the real data sets and simulation data shows that the real-coded genetic algorithm may offer efficient alternative to traditional training methods for the classification problem.     

求解全局优化问题的混合智能算法

把序列二次规划作为遗传算法的一个局部搜索算子,嵌入到实数编码遗传算法中,构成一种基于序列二次规划和实数编码遗传算法的高效的混合智能算法。该方法充分利用序列二次规划法的强局部搜索能力和遗传算法的全局收敛性,使得混合算法的全局收敛性得到改善并且减少了计算量。数值实验结果表明,混合算法是高效可靠的。     

基于遗传算法的数码问题求解

在人工智能研究中，数码问题常被用来作为一些搜索算法的测试实例。数码问题的搜索空间巨大，对于24数码问题，目前最好的启发式搜索算法找到最优解(最少移动步数)通常也至少需要2．25小时^[1]。遗传算法具有简单、通用、鲁棒性强的特点，适合于在复杂而庞大的搜索空间中寻找最优解。该文给出了求解该问题的遗传算法，并针对遗传算法容易过早收敛的问题，对传统遗传算法进行了改进。通过用多个随机生成的]5数码和24数码问题作为测试实例，本算法均在较短的时间内找到了问题的解，从而证明了算法的有效性。     

一种求解三维集装箱装箱问题的混合遗传算法

在遗传算法的基础上结合传统启发式装箱算法,设计了一个混合遗传算法,该算法既继承了遗传算法的全局搜索好的优点,也克服了遗传算法局部搜索能力差的缺点,能够较好地解决集装箱这类多目标多约束的空间三维分布的问题。