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 共查询到10条相似文献,搜索用时 125 毫秒
1.
Dynamic optimization problems challenge traditional evolutionary algorithms seriously since they, once converged, cannot adapt quickly to environmental changes. This paper investigates the application of memetic algorithms, a class of hybrid evolutionary algorithms, for dynamic optimization problems. An adaptive hill climbing method is proposed as the local search technique in the framework of memetic algorithms, which combines the features of greedy crossover-based hill climbing and steepest mutation-based hill climbing. In order to address the convergence problem, two diversity maintaining methods, called adaptive dual mapping and triggered random immigrants, respectively, are also introduced into the proposed memetic algorithm for dynamic optimization problems. Based on a series of dynamic problems generated from several stationary benchmark problems, experiments are carried out to investigate the performance of the proposed memetic algorithm in comparison with some peer evolutionary algorithms. The experimental results show the efficiency of the proposed memetic algorithm in dynamic environments.  相似文献   

2.
Constructive multistart search algorithms are commonly used to address combinatorial optimization problems; however, constructive multistart search algorithm performance is fundamentally affected by two factors: (i) The choice of construction algorithm utilized and (ii) the rate of state space search redundancy. Construction algorithms are typically specific to a particular combinatorial optimization problem; therefore, we first investigate construction algorithms for iterative hill climbing applied to the traveling salesman problem and experimentally determine the best performing algorithms. We then investigate the more general problem of utilizing record‐keeping mechanisms to mitigate state space search redundancy. Our research shows that a good choice of construction algorithm paired with effective record keeping significantly improves the quality of traveling salesmen problem solutions in a constant number of state explorations. Particularly, we show that Bloom filters considerably improve time performance and solution quality for iterative hill climbing approaches to the traveling salesman problem.  相似文献   

3.
提出了一种解决车间调度问题的新方法, 该方法将序优化思想融入巢分区算法框架, 采用"序比较"的方法进行算法的局部寻优. "序"的指数收敛性加快了巢分区算法的局部收敛速度, 从而提高了算法整体的优化效率. 最优计算量分配技术则依据在线数据对计算量进行合理的分配, 进一步提高算法的收敛速度和结果的可靠性. 混合算法继承了巢分区算法的全局搜索特性以及序优化的快速收敛性. 用该算法解决标准 Jobshop 调度问题, 并与序优化方法和模拟退火算法进行比较, 发现本文算法在收敛速度与优化质量方面均优于这些算法.  相似文献   

4.
基于成长算子的改进遗传算法及仿真   总被引:1,自引:0,他引:1  
模拟生物界成长发育过程,加入成长算子对遗传算法框架进行改进,形成新的算法框架-成长遗传算法(growth GA).该算法能够克服简单遗传算法寻优速度较慢、局部搜索能力较弱的缺点.利用爬山法局部搜索能力强的特点,给出成长算子的一种具体实现,并证明加入成长算子不改变算法收敛性.与简单遗传算法和确定性拥挤遗传算法的对比函数优化实验证明:成长遗传算法有利于兼顾寻优速度和收敛精度.  相似文献   

5.
Generalized hill climbing (GHC) algorithms provide a well-defined framework for describing the performance of local search algorithms for discrete optimization problems. Necessary and sufficient convergence conditions for GHC algorithms are presented. These convergence conditions are derived using a new iteration classification scheme for GHC algorithms. The implications of the necessary and the sufficient convergence conditions fur GHC algorithms with respect to existing convergence theory for simulated annealing are also discussed  相似文献   

6.
This paper presents a new hybrid optimization approach based on immune algorithm and hill climbing local search algorithm. The purpose of the present research is to develop a new optimization approach for solving design and manufacturing optimization problems. This research is the first application of immune algorithm to the optimization of machining parameters in the literature. In order to evaluate the proposed optimization approach, single objective test problem, multi-objective I-beam and machine-tool optimization problems taken from the literature are solved. Finally, the hybrid approach is applied to a case study for milling operations to show its effectiveness in machining operations. The results of the hybrid approach for the case study are compared with those of genetic algorithm, the feasible direction method and handbook recommendation.  相似文献   

7.
大规模特征选择问题的求解通常面临两大挑战:一是真实标签不足,难以引导算法进行特征选择;二是搜索空间规模大,难以搜索到满意的高质量解。为此,提出了新型的面向大规模特征选择的自监督数据驱动粒子群优化算法。第一,提出了自监督数据驱动特征选择的新型算法框架,可不依赖于真实标签进行特征选择。第二,提出了基于离散区域编码的搜索策略,帮助算法在大规模搜索空间中找到更优解。第三,基于上述的框架和方法,提出了自监督数据驱动粒子群优化算法,实现对问题的求解。在大规模特征数据集上的实验结果显示,提出的算法与主流有监督算法表现相当,并比前沿无监督算法具有更高的特征选择效率。  相似文献   

8.
求解全局最优化的遗传(GA)-Alopex算法的研究   总被引:13,自引:0,他引:13  
针对遗传算法爬山能力差的弱点,对传统遗传算法进行改进,提出了将遗传算法与Alop ex(Algorithms of pattern extraction)算法相结合,结合在一起的混合算法充分发挥了 两者的优越性,对典型函数的测试表明该算法提高了遗传算法的计算速度和计算精度.  相似文献   

9.
Searching within the sample space for optimal solutions is an important part in solving optimization problems. The motivation of this work is that today’s problem environments have increasingly become dynamic with non-stationary optima and in order to improve optima search, memetic algorithm has become a preferred search method because it combines global and local search methods to obtain good solutions. The challenge is that existing search methods perform the search during the iterations without being guided by solid information about the nature of the search environment which affects the quality of a search outcome. In this paper, a spy search mechanism is proposed for memetic algorithm in dynamic environments. The method uses a spy individual to scope out the search environment and collect information for guiding the search. The method combines hyper-mutation, random immigrants, hill climbing local search, crowding and fitness, and steepest mutation with greedy crossover hill climbing to enhance the efficiency of the search. The proposed method is tested on dynamic problems and comparisons with other methods indicate a better performance by the proposed method.  相似文献   

10.
于坤杰  王昕  王振雷 《自动化学报》2014,40(9):1976-1983
精英教学优化算法(Elitist teaching-learning-based optimization,ETLBO)是一种基于实际班级教学过程的新型优化算法. 本文针对ETLBO算法寻优精度低、稳定性差的问题,提出了反馈精英教学优化算法(Feedback ETLBO). 在ETLBO算法的基础上,通过在学生阶段之后加入反馈阶段,增加了学生的学习方式,保持学生的多样性特性,提高算法的全局搜索能力. 同时,反馈阶段是选举成绩较差的学生与教师交流,使成绩较差的学生快速向教师靠拢,使算法进行局部精细搜索,提高算法的寻优精度. 对6个无约束及5个约束标准函数的测试结果表明,FETLBO算法与其他算法相比在寻优精度和稳定性上更具优势. 最后将FETLBO算法应用于拉压弹簧优化设计问题及0-1背包问题,取得了满意结果.  相似文献   

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