自适应变异率的遗传算法

标准遗传算法的变异运算以固定的变异率进行操作,即不管遗传个体的适应度大小, 所有个体的染色体均以不变的概率进行变异.该文根据遗传个体的适应度值自适应地确定各个个体变异率,适应度值大的个体以较小的概率进行变异,而适应度值小的个体以较大的概率进行变异.通过这种方法,可以减少优秀染色体模式被变异破坏的可能性,从而提高遗传寻优计算的效率,加快遗传算法的收敛速度.     

基于染色体遗传规律的遗传算法

给出了一种基于染色体遗传规律的二进制遗传算法--在编码中,对个体进行成对等位基因编码,同时把个体的所有基因分成一定数量的染色体(基因片断);在交叉中,从父代中随机抽取染色体组成新的个体;在变异中,应用染色体基因交换;在求适应度时,以一对等位基因"或"的结果作为计算该基因适应度值时的依据.对两个较复杂的测试函数实验结果表明,该方法具有进化代数少、收敛率高的特点,其性能明显优于标准遗传算法.     

基于动态入侵的自适应遗传算法研究

根据生物入侵的思想,将入侵的概念引入到遗传算法中,提出了一种新的基于动态入侵自适应遗传算法。在选择操作结束后,根据当前的种群类型自适应调整入侵率;根据种群所属的种群类型和种群的平均适应度值,确定染色体交叉概率;根据个体的所属类型和变异基因位置自适应调整变异概率。最后将该算法应用到函数优化问题,实验结果表明,改进后的算法在种群的多样性,收敛速度以及算法效率方面有了一定的改进。     

基于父个体相似度的自适应遗传算法

标准遗传算法在产生后代个体时采用先交叉后变异的策略,一方面当父个体非常相似时,交叉操作很难产生新的个体,影响算法对新的解空间进行搜索,从而导致种群多样性的丧失;另一方面交叉产生的优秀个体再历经变异,极有可能遭破坏而影响算法的收敛性。该文根据染色体的相似性,给出了个体相似度的概念,并在此基础上提出了依据父个体相似度的大小自适应地选择遗传算子(交叉或变异)的遗传算法。仿真实验表明,与采用常规遗传策略的遗传算法相比,新算法能显著提高解的质量和收敛速度。     

遗传算法在自动组卷系统中的应用

用基因段的遗传算法解决自动组卷问题,采用二进制进行编码,生成带有约束条件的初始种群,用自适应的概率对染色体进行选择、交叉和变异．在一个染色体的基因段内完成交叉和变异操作,从而产生新的种群。     

改进的自适应遗传算法求解0/1背包问题

为提高遗传算法求解问题的性能,提出一种改进的自适应遗传算法,该算法在交叉概率和变异概率公式中引入了当代迭代次数因子,提出了基因差别比例（Ca）的概念。Ca越大的基因位发生交叉、变异的概率越大,产生新个体的可能性越大;在模式生成操作中,确定基因位的选取同样由Ca决定。仿真结果表明,此算法在求解0/1背包问题时,其寻优能力有很大提高。     

基于量子位Bloch坐标的量子遗传算法及其应用

提出了一种基于量子位Bloch坐标的量子遗传算法. 该方法用量子位构成染色体; 用量子位的Bloch坐标构成染色体上的基因位; 用量子旋转门进行染色体上量子位的更新; 用量子非门进行染色体变异. 对于量子旋转门的转角大小及方向的确定, 提出了一种简易快捷的新方法; 对旋转和变异操作, 提出了基于量子位Bloch坐标的新算子. 该算法将量子位的3个Bloch 坐标都看作基因位, 每条染色体包含3条并列的基因链, 每条基因链代表1个优化解.在染色体数目相同时, 可加速优化进程. 以函数极值优化和神经网络权值优化为例, 仿真结果表明该方法在搜索能力和优化效率两个方面优于普通量子遗传算法和简单遗传算法.     

组卷的遗传算法设计

提出一种改进的遗传算法作为组卷的策略.染色体采用符号编码设计,解决了遗传运算过程中满足约束条件的问题.采用"非优超排序法"对染色体进行评价,在选择算子的设计上,既能够复制一部分较好的个体,又体现了选择的概率性.变异概率和交叉概率能随个体的不同适应度自适应改变,同时变异概率随种群多样性自适应变化.采用基于数据仓库的最优解保存策略,使搜索结果呈现出丰富的Pareto解集.     

一种维持种群多样性的遗传算法变异算子的研究

本文针对二进制编码遗传算法中，由于传统变异算子随机地选取基因位置而对搜索全局最优的不利影响，分析了变异位置对种群多样性的影响．提出了一种新的维持种群多样性的变异算子，其变异概率和变异位置由种群基因位的多样度和个体适应度值自适应决定．经变异后优秀的个体得以保存，且在种群中每一基因坐上两种基因的比例控制在期望的范围内．本文最后用实验验证了该算于维持种群多样性的有效性．     

自适应变异遗传算法及其应用

为了改善变异操作在遗传算法中的作用,提出自适应变异遗传算法,其变异操作能根据种群进化代数和个体的适应度值自适应地确定每个个体的变异概率,从而在保留遗传算法当前最优解的同时,维持了群体的多样性,提高了算法的全局搜索能力.与传统遗传算法相比,自适应变异遗传算法的离线性能和在线性能都有较大的改善.本文在实际应用中,将自适应变异遗传算法应用于估计动力学参数取得了较好的结果.     

自适应多位变异遗传算法的实现

Genetic algorithm is a widely used optimization method. Crossover and mutation are two Basicl operatorsof the genetic algorithm. On the basis of analyzing the principles of simple genetic algorithm and discussing its exist-ing problems of crossover point and mutation bit, this paper presents a way of the adaptive multiple bit mutation ge-netic algorithm , which not only can keep the population diversity but also has quicker convergence speed. The resultsof the multi-modal function optimization show that the adaptive multiple bit mutation genetic algorithm is practical and efficient.     

Phase transitions and symmetry breaking in genetic algorithms with crossover

In this paper, we consider the role of the crossover operator in genetic algorithms. Specifically, we study optimisation problems that exhibit many local optima and consider how crossover affects the rate at which the population breaks the symmetry of the problem. As an example of such a problem, we consider the subset sum problem. In doing so, we demonstrate a previously unobserved phenomenon, whereby the genetic algorithm with crossover exhibits a critical mutation rate, at which its performance sharply diverges from that of the genetic algorithm without crossover. At this critical mutation rate, the genetic algorithm with crossover exhibits a rapid increase in population diversity. We calculate the details of this phenomenon on a simple instance of the subset sum problem and show that it is a classic phase transition between ordered and disordered populations. Finally, we show that this critical mutation rate corresponds to the transition between the genetic algorithm accelerating or preventing symmetry breaking and that the critical mutation rate represents an optimum in terms of the balance of exploration and exploitation within the algorithm.     

基于自适应并行遗传算法的泊松曲线沉降预测模型

针对简单遗传算法采用固定的交叉概率和变异概率不能总是满足当前种群的需要,影响算法的性能及效率,采用自适应的交叉概率和变异概率,且将并行技术与遗传算法相结合,提出自适应并行遗传算法,用于泊松曲线沉降预测模型的优化。实验结果表明,该算法为泊松曲线沉降预测模型的参数估计提供了一种有效的方法。     

Evolution of Appropriate Crossover and Mutation Operators in a Genetic Process

Traditional genetic algorithms use only one crossover and one mutation operator to generate the next generation. The chosen crossover and mutation operators are critical to the success of genetic algorithms. Different crossover or mutation operators, however, are suitable for different problems, even for different stages of the genetic process in a problem. Determining which crossover and mutation operators should be used is quite difficult and is usually done by trial-and-error. In this paper, a new genetic algorithm, the dynamic genetic algorithm (DGA), is proposed to solve the problem. The dynamic genetic algorithm simultaneously uses more than one crossover and mutation operators to generate the next generation. The crossover and mutation ratios change along with the evaluation results of the respective offspring in the next generation. By this way, we expect that the really good operators will have an increasing effect in the genetic process. Experiments are also made, with results showing the proposed algorithm performs better than the algorithms with a single crossover and a single mutation operator.     

一种新的基于遗传操作的改进型遗传算法

交叉与变异是遗传算法的重要操作,提出了一种新的基于遗传操作的改进型遗传算法.采用最优保留和改进的轮盘赌选择方法,通过基因交叉概率控制交叉,根据高斯分布改进了交叉算子和变异算子,保证了算法的全局搜索能力、局部搜索能力及收敛速度.通过标准函数的数值实验,验证了新算法的有效性.     

遗传算法在求解最小生成树中的运用

以图论和遗传算法为基础,提出了求解最小生成树问题的遗传算法。该算法解决了常用二进制编码不能正确表达最小生成树的问题,利用Prufer数对生成树进行编码;在遗传操作中对变异算子进行了改进,避免了由于变异产生大量不可行解。从而提高了遗传算法的效率;通过数值试验,表明该算法简单,高效,收敛率高。     

图像关联规则挖掘研究*

介绍了图像关联规则的相关概念,描述了传统的双种群遗传算法的执行过程;针对采用固定染色体交叉概率和染色体变异概率容易出现早熟、收敛速度较慢等问题,设计出了能自适应调整的染色体交叉算子和变异算子。最后将改进后的双种群遗传算法成功地运用到Landsat卫星遥感图像,实现了图像关联规则的提取,为退耕还林决策提供了有力的依据。     

Genetic algorithm with the dynamic probability of mutation in the classification problem

A method of dynamic establishment of mutation probability in the genetic algorithm generation has been proposed in this paper. Results obtained by means of the genetic algorithm with constant and variable mutation probability respectively, have been compared. These methods have been tested on biomedical data.     

Improved genetic algorithm inspired by biological evolution

The process of mutation has been studied extensively in the field of biology and it has been shown that it is one of the major factors that aid the process of evolution. Inspired by this a novel genetic algorithm (GA) is presented here. Various mutation operators such as small mutation, gene mutation and chromosome mutation have been applied in this genetic algorithm. In order to facilitate the implementation of the above-mentioned mutation operators a modified way of representing the variables has been presented. It resembles the way genetic information is coded in living beings. Different mutation operators pose a challenge as regards the determination of the optimal rate of mutation. This problem is overcome by using adaptive mutation operators. The main purpose behind this approach was to improve the efficiency of GAs and to find widely distributed Pareto-optimal solutions. This algorithm was tested on some benchmark test functions and compared with other GAs. It was observed that the introduction of these mutations do improve the genetic algorithms in terms of convergence and the quality of the solutions.