一种基于种群熵的自适应遗传算法

遗传算法中的交叉概率和变异概率是影响算法行为和性能的关键所在,直接影响算法的收敛速度,甚至影响有限进化代内的收敛性。本文通过分析交叉概率和变异概率对算法的影响,设计了一种依据种群多样性和进化代数自适应调节的交叉概率和变异概率,改善了传统遗传算法存在＂早熟＂现象和算法后期收敛速度慢的不足。最后,给出了三个典型函数的模拟例子,通过与传统SGA和AGA的对比结果显示,本文的改进提高了算法的性能。     

基于捕食搜索策略的遗传算法研究

针对标准遗传算法易陷入局部最优而出现早熟,提出了一种基于捕食搜索策略的遗传算法。该算法在进化中模拟动物捕食搜索的过程,并根据种群中个体最优适应值来动态改变交叉和变异概率,从而加强算法的全局搜索和局部优化的能力。仿真实验表明该算法是有效的。     

基于进化个体适应值灰度的自适应交互式遗传算法

为将交互式遗传算法成功应用于复杂优化问题,有必要提高交互式遗传算法的性能。提出基于进化个体适应值灰度的交互式遗传算法,该算法采用灰度衡量进化个体的适应值评价不确定性;通过适应值区间的分析,提取反映进化种群分布的信息;基于此,给出了进化个体的交叉和变异概率。将该算法应用于服装进化设计系统,结果表明该算法在每代可以获取更多的满意解。     

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．     

一种改进的遗传算法

介绍了遗传算法的起源以及基本概念。从模仿生物遗传进化的角度出发,在参考现有遗传算法的基础上设计一种可以随适应度变化而变化的遗传算法模型。现有的遗传算法往往计算度过于复杂,且容易过早收敛,不能得到精确解。通过该算法与标准遗传算法在选择的实验模型上比较,可以清楚地看到所改进的算法的优越性能。仿真表明,该模型不仅具有良好的实验效果,还有很高的进化效率,求得目标的成功性也高多了。     

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．     

遗传算法种群多样性的分析研究

种群的多样性是遗传算法法进化的前提条件，本文提出用种群方案方差和熵两个量来全面刻画遗传算法中的种群的多样性，分析了选择，交换和变异三个主要算子对种群方差和熵的影响，同时比较了编码机制对种群多样性的影响，得出一些重析结论。     

遗传算法中交叉和变异概率选择的自适应方法及作用机理

在指出了传统遗传算法中交叉和变异概率的选择具有盲目性的基础上, 提出了遗传算法中交叉和变异概率选择的改进措施, 对其作用机理进行了深入的分析, 指出改进算法体现了自适应策略. 用一个非常复杂的数学函数对新算法进行了测试, 结果表明改进算法克服了传统遗传算法难以解决的早熟和局部收敛的问题.     

一种强引导进化型遗传算法

针对遗传算法随机性过强,收敛速度慢的问题,从选择机制、交叉算子、变异算子三方面强化了对进化方向的引导,提出了“保留最优,调节中间,淘汰最差”的确定型选择策略．用基因调节加自适应变焦微调算子代替常规的交叉算子,用淘汰替代方式代替变异算子,构造出一种强化引导型遗传算法．多变量函数优化的仿真计算结果说明了该算法的有效性．     

利用改进的自适应遗传算法确定有机化合物分子式

针对简单遗传算法存在早熟和收敛速度慢的缺点,提出了一种改进的自适应遗传算法用来确定有机化合物分子式.在现有自适应遗传算法的基础上,对编码方式和遗传算子操作等几方面进行了改进.改进后的自适应遗传算法在防止早熟和加快收敛方面优于简单遗传算法.该算法应用到确定有机化合物分子式时,取得很好的效果.     

Virus detection using clonal selection algorithm with Genetic Algorithm (VDC algorithm)

This paper presents a novel approach for computer viruses detection based on modeling the structures and dynamics of real life paradigm that exists in the bodies of all living creatures. It aims to develop an algorithm based on the concept of the artificial immune system (AIS) for the purpose of detecting viruses. The algorithm is called Virus Detection Clonal algorithm (VDC), and it is derived from the clonal selection algorithm. The VDC algorithm consists of three basic steps: cloning, hyper-mutation and stochastic re-selection. In later stage, the developed VDC algorithm is subjected to validation, which consists of two phases; learning and testing. Two main parameters are determined; one of them is setting the number of signatures per clone (Fat), while the other defines the hypermutation probability (Pm). Later on, the Genetic Algorithm (GA) is used as a tool, to improve the developed algorithm by searching the values of the main parameters (Fat and Pm) to reproduce better results. The results have shown that the detection rate of viruses, by using the developed algorithm, is 94.4%, whereas the detection rate of false positives has reached 0%. These percentages indicate that the VDC algorithm is sufficient and usable in this field. Moreover, the results of employing the GA to optimize the VDC algorithm have shown an improvement in the detection speed of the algorithm.     

Parallelization of a dynamic unstructured algorithm using three leading programming paradigms

The success of parallel computing in solving real-life computationally intensive problems relies on their efficient mapping and execution on large-scale multiprocessor architectures. Many important applications are both unstructured and dynamic in nature, making their efficient parallel implementation a daunting task. This paper presents the parallelization of a dynamic unstructured mesh adaptation algorithm using three popular programming paradigms on three leading supercomputers. We examine an MPI message-passing implementation on the Cray T3E and the SGI Origin2000, a shared-memory implementation using the cache coherent nonuniform memory access (CC-NUMA) feature of the Origin2000, and a multithreaded version on the newly released Tera Multithreaded Architecture (MTA). We compare several critical factors of this parallel code development, including runtime, scalability, programmability, portability, and memory overhead. Our overall results demonstrate that multithreaded systems offer tremendous potential for quickly and efficiently solving some of the most challenging real-life problems on parallel computers.     

Genetic K-means algorithm

In this paper, we propose a novel hybrid genetic algorithm (GA) that finds a globally optimal partition of a given data into a specified number of clusters. GA's used earlier in clustering employ either an expensive crossover operator to generate valid child chromosomes from parent chromosomes or a costly fitness function or both. To circumvent these expensive operations, we hybridize GA with a classical gradient descent algorithm used in clustering, viz. K-means algorithm. Hence, the name genetic K-means algorithm (GKA). We define K-means operator, one-step of K-means algorithm, and use it in GKA as a search operator instead of crossover. We also define a biased mutation operator specific to clustering called distance-based-mutation. Using finite Markov chain theory, we prove that the GKA converges to the global optimum. It is observed in the simulations that GKA converges to the best known optimum corresponding to the given data in concurrence with the convergence result. It is also observed that GKA searches faster than some of the other evolutionary algorithms used for clustering.     

Self-adaptive differential evolution algorithm using population size reduction and three strategies

Many real-world optimization problems are large-scale in nature. In order to solve these problems, an optimization algorithm is required that is able to apply a global search regardless of the problems’ particularities. This paper proposes a self-adaptive differential evolution algorithm, called jDElscop, for solving large-scale optimization problems with continuous variables. The proposed algorithm employs three strategies and a population size reduction mechanism. The performance of the jDElscop algorithm is evaluated on a set of benchmark problems provided for the Special Issue on the Scalability of Evolutionary Algorithms and other Metaheuristics for Large Scale Continuous Optimization Problems. Non-parametric statistical procedures were performed for multiple comparisons between the proposed algorithm and three well-known algorithms from literature. The results show that the jDElscop algorithm can deal with large-scale continuous optimization effectively. It also behaves significantly better than other three algorithms used in the comparison, in most cases.     

Comparison of three individual tree crown detection methods

Three image processing methods for single tree crown detection in high spatial resolution aerial images are presented and compared using the same image material and reference data. The first method uses templates to find the tree crowns. The other two methods uses region growing. One of them is supported by fuzzy rules while the other uses an image produced by Brownian motion. All three methods detect around 80%, or more, of the visible sunlit trees in two pine Pinus Sylvestris L.) and two spruce stands Picea abies Karst.) in a boreal forest. For all methods, large tree crowns are easier to detect than small ones.     

遗传算法求解FDP问题

FDP(Film-copy Delivering Problem)问题是一个典型的NP-Hard组合优化问题,长期以来,人们一直在寻求快速、高效的近似算法。介绍了一种适于求解FDP问题的遗传算法,详细地介绍了边重组杂交算子、反转变异算子的设计和分配选择概率的线性函数。通过实验表明,该算法正确、可行,而且计算的结果精确、快速。     

遗传算法求解VRP问题

在分析了许多求解固定车辆路径问题的优化算法后,提出了一种新的求解固定车辆路径问题的遗传算法。该算法的核心在于构建一种新的染色体编码,并且将“Inver-0ver”遗传操作算子与禁忌搜索算法结合起来,利用种群的信息引导种群的进化。引入动态非法检测来淘汰不合法个体,扩展了解空间并加快了搜索速度。经过大量的实例测试,该遗传算法增强了群体演化的质量,提高了算法收敛速度,能够找到比较好的近似最优解。     

基于中心定位算子的遗传算法

针对遗传算法局部搜索能力弱,求解精度不高的缺陷提出了一种中心定位算子.在进化一定代数(T)后,选择最优的若干个(N)染色体基因来计算中心定位算子,从而确定与中心定位算子相同的基因位,并且在以后的交叉、变异操作中,都不让相同的基因位参与.随着算法的进行,染色体相同的基因位逐渐全部地被确定下来.其次,通过与小生境技术的局部搜索能力算法的结合,提高了该算子的全局优化能力;最后,通过几个非常容易陷入局部最优的测试函数测试表明几乎所有的峰值都得到了理论值.     

个体行为数据聚类的双重混合高斯模型算法

传统的基于概率的混合模型算法可以很好地解决个体行为数据的聚类问题,但是对于具有“多峰值”特征的行为数据则需要更精巧的方法。提出双重混合高斯模型算法(DualMGM)扩展了普通混合模型的概念,解决了多峰值特征的个体行为数据的聚类问题。DualMGM的算法复杂度是随数据量线性增长的,具有很好的可扩展性。     

可调整个体优先级的双边匹配算法

针对传统双边匹配算法单边占优、缺乏最低保障以及无法精细调控个体优先级等问题,提出了可通用于一对一、一对多、多对多双边匹配的WYS算法。WYS算法通过外生给定优先级,使得每个参与主体都有机会遍历自身偏好序中全部对象,从而显著提高匹配结果中最差群体的效用以及全体总效用,并能够对个体效用进行精确调控。随后按照诺奖得主Roth提出的“经济工程学”范式设计实验对WYS算法的性质进行了深入探讨,大量随机实验表明WYS算法匹配结果稳定,能够给予参与主体某种程度的最低保障,且不存在单边占优问题。WYS算法对于维持市场厚度、兼顾效率与公平有重要意义,拓宽了匹配理论的应用范围。