共查询到20条相似文献,搜索用时 15 毫秒
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约束优化问题的混合遗传算法研究 总被引:1,自引:0,他引:1
如何处理约束条件与增强局部搜索能力是遗传算法用于非线性约束优化问题的线性约束优化问题的不足,提出了一种基于模拟退火算法与外点法的混合遗传算法,对于不满足约束条件的解用外点罚函数法来修正,同时把退火选择算子作为一个与选择、交叉和变异平行的算子,嵌入到实数编码的遗传算法中,来增强其的局部搜索能力.算法兼顾了遗传算法、模拟退火算法和外点法三者的长处,既有较快的收敛速度,又能以较大的概率求得非线性约束优化问题的全局最优解.最后以两个测试函数为算例对算法进行测试,验证了该算法搜索能力强、稳健性好,能获得更好的优化结果.实验结果表明引入外点法处理约束条件是可行的. 相似文献
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一种新的遗传算法求解约束优化问题 总被引:4,自引:0,他引:4
采用十进制编码的遗传算法,在进化计算中提出用排序、保留优秀个体、智能变异和随机变异代替以前遗传算法中的选择、交叉和变异,此算法具有简单的计算原因,简化了遗传算法的编程,利用变换后的目标函数构造适配值,能较快的找到最优解,数值实验表明该算法在求解有约束优化问题上表现良好。 相似文献
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在计算机网络中,随着大量新兴多媒体实时业务的应用,组播路由问题成为越来越重要的课题。组播路由问题在计算机网络中是著名的Steiner树问题,同时也是NP完全问题。目前许多研究者在单约束(特别是延时约束)组播路由中取得了较好的成果,但对于多约束Qos组播路由方面的研究相对比较少。论文提出了一种基于遗传算法的多约束组播路由优化算法,该算法在满足带宽、延时、延时抖动和包丢失率约束条件下寻找代价最小的组播树,文中描述了一种适应于研究Qos组播路由的网络模型。最后通过仿真实验证明该算法操作简单、搜索速度快、效率高且具有较强的实用性和鲁棒性。 相似文献
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An algorithm has been developed to dynamically schedule heterogeneous tasks on heterogeneous processors in a distributed system.
The scheduler operates in an environment with dynamically changing resources and adapts to variable system resources. It operates
in a batch fashion and utilises a genetic algorithm to minimise the total execution time. We have compared our scheduler to
six other schedulers, three batch-mode and three immediate-mode schedulers. Experiments show that the algorithm outperforms
each of the others and can achieve near optimal efficiency, with up to 100,000 tasks being scheduled 相似文献
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Yuren Zhou Jun He 《Evolutionary Computation, IEEE Transactions on》2007,11(5):608-619
Although there are many evolutionary algorithms (EAs) for solving constrained optimization problems, there are few rigorous theoretical analyses. This paper presents a time complexity analysis of EAs for solving constrained optimization. It is shown when the penalty coefficient is chosen properly, direct comparison between pairs of solutions using penalty fitness function is equivalent to that using the criteria ldquosuperiority of feasible pointrdquo or ldquosuperiority of objective function value.rdquo This paper analyzes the role of penalty coefficients in EAs in terms of time complexity. The results show that in some examples, EAs benefit greatly from higher penalty coefficients, while in other examples, EAs benefit from lower penalty coefficients. This paper also investigates the runtime of EAs for solving the 0-1 knapsack problem and the results indicate that the mean first hitting times ranges from a polynomial-time to an exponential time when different penalty coefficients are used. 相似文献
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基于遗传算法的退火精确罚函数非线性约束优化方法 总被引:56,自引:1,他引:56
提出了一种新的基于遗传算法求解非线性约束优化的方法,通过自适应的退火罚因子和不可微精确罚函数未处理的约束条件,可以使算法逐渐收敛于可行的极值点,仿真结果表明该方法有较刘的求解精度。 相似文献
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用GA寻优线性系统模糊控制器规则 总被引:3,自引:0,他引:3
控制精度和自适应能力一直是模糊控制应用中较难解决的问题,解决这一问题的关键在于选取适当的控制规则,而遗传算法可以较好地解决常规的数学优化技术所不能有效解决的问题。该文给出了对于具有修正因子的控制规则,采用遗传算法对其参数进行自调整的方法,它可提高模糊控制器的性能。通过仿真实验表明了该方法对于线性系统的控制是有效的。 相似文献
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一种新的求解约束多目标优化问题的遗传算法 总被引:6,自引:1,他引:5
由于采用罚函数法将有约束多目标优化问题转化为无约束多目标优化问题会使求解不合理,因此,文章首先在无约束Pareto排序遗传算法的基础上,提出了一个简单、实用的能分别考虑目标函数和约束函数,而又可以避免采用罚函数的全新排序方法。接着,针对小生境技术在遗传后期依旧会出现遗传漂移现象和共享半径不易确定等缺陷,提出了一种易于实现的超量惩罚策略来替代小生境技术,用以改进种群的多样性。此外,还采用了Pareto解集过滤器、邻域变异和群体重组等策略对算法的寻优能力进行改进,并最终形成了一种求解有约束多目标优化问题的Pareto遗传算法(CMOPGA),还给出了具体的算法流程图。最后采用两个数值算例对算法的求解性能进行了测试。数值试验表明,采用CMOPGA可方便地求得问题的Pareto前沿,并能使求得的Pareto最优解集具有可靠、均布、多样等特点。 相似文献
11.
XIE Da-tong 《数字社区&智能家居》2008,(11)
从遗传算法的编码、遗传算子等方面剖析了遗传算法求解无约束函数优化问题的一般步骤,并以一个实例说明遗传算法能有效地解决函数优化问题。 相似文献
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约束优化进化算法综述 总被引:3,自引:0,他引:3
约束优化进化算法主要研究如何利用进化计算方法求解约束优化问题,是进化计算领城的一个重要研究课题.约束优化问题求解存在约束区域离散、等式约束、非线性约束等挑战,其问题的本质是如何处理可行解与不可行解的关系才能使得算法更高效.本文首先介绍了约束优化问题的定义,然后系统地分析了目前存在的约束优化方法,同时基于约束处理机制将这些方法分为罚函数法、可行性法则、随机排序法、约束处理法、多目标优化法、混合法六类,并从约束处理方法的方面对约束优化进化算法的最新研究进展进行综述.最后,指出约束优化进化算法需进一步研究的方向与关键问题. 相似文献
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采用最大类间方差法、最大熵法和最小误差法3种经典全局阈值方法获得的阈值,存在一定偏差.针对该问题,提出了一种采用高斯拟合的全局阈值算法阈值优化框架(TOF).本优化框架先利用全局阈值算法获得初始阈值,将图像粗分为背景和目标2个部分,然后分别计算各部分均值和方差来拟合出2个高斯分布.由于最佳阈值位于2个高斯分布的交点位置,为此本框架采用多次迭代方式来优化阈值,直至最终收敛到最佳阈值.为提高抗噪性能,结合三维直方图重建和降维思想,提出了一种鲁棒的采用高斯拟合的全局阈值算法阈值优化框架(RTOF).实验结果表明,对于以上经典全局算法,采用本优化方法均能收敛到一个最佳阈值,同时本算法还具有鲁棒的抗噪性能和较高的执行效率. 相似文献
14.
利用遗传算法搜索出最优的初始值和嵌入强度,提出了一种新的离散多小波变换域的数字图像水印算法.实验结果表明,使用此算法能提高数字水印对于各种改变的鲁棒性,同时保证数字水印的不可感知性. 相似文献
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约束优化是多数实际工程应用优化问题的呈现方式.进化算法由于其高效的表现,近年来被广泛应用于约束优化问题求解.但约束条件使得问题解空间离散、缩小、改变,给进化算法求解约束优化问题带来极大挑战.在此背景下,融合约束处理技术的进化算法成为研究热点.此外,随着研究的深入,近年来约束处理技术在复杂工程应用问题优化中得到了广泛发展,例如多目标、高维、等式优化等.根据复杂性的缘由,将面向复杂约束优化问题的进化优化分为面向复杂目标的进化约束优化算法和面向复杂约束场景的进化算法两种类别进行综述,其中,重点探讨了实际工程应用的复杂性对约束处理技术的挑战和目前研究的最新进展,并最后总结了未来的研究趋势与挑战. 相似文献
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Using Genetic Algorithms for Concept Learning 总被引:23,自引:0,他引:23
In this article, we explore the use of genetic algorithms (GAs) as a key element in the design and implementation of robust concept learning systems. We describe and evaluate a GA-based system called GABIL that continually learns and refines concept classification rules from its interaction with the environment. The use of GAs is motivated by recent studies showing the effects of various forms of bias built into different concept learning systems, resulting in systems that perform well on certain concept classes (generally, those well matched to the biases) and poorly on others. By incorporating a GA as the underlying adaptive search mechanism, we are able to construct a concept learning system that has a simple, unified architecture with several important features. First, the system is surprisingly robust even with minimal bias. Second, the system can be easily extended to incorporate traditional forms of bias found in other concept learning systems. Finally, the architecture of the system encourages explicit representation of such biases and, as a result, provides for an important additional feature: the ability todynamically adjust system bias. The viability of this approach is illustrated by comparing the performance of GABIL with that of four other more traditional concept learners (AQ14, C4.5, ID5R, and IACL) on a variety of target concepts. We conclude with some observations about the merits of this approach and about possible extensions. 相似文献
19.
ANGELO MONFROGLIO 《Software》1996,26(3):251-279
Hybrid genetic algorithms are presented that use constrained heuristic search and genetic techniques for the timetabling problem (TP). The TP is an NP-hard problem for which a general polynomial time deterministic algorithm is not known. The paper describes the classification of constraints and the constraint ordering to obtain the minimization of backtracking and the maximization of parallelism. The school timetabling problem is discussed in detail as a case study. The genetic algorithm approach is particularly well suited to this kind of problem, since there exists an easy way to assess a good timetable, but not a well structured automatic technique for constructing it. So, a population of timetables is created that evolves toward the best solution. The evaluation function and the genetic operators are well separated from the domain-specific parts, such as the knowledge of the problem and the heuristics, i.e. from the timetable builder. The present paper illustrates an approach based on the hybridization of constrained heuristic search with novel genetic algorithm techniques. It compares favourably with known programs to solve decision problems under logic constraints. The cost of the new algorithm and the quality of the solutions obtained in significant experiments are reported. 相似文献
20.
遗传算法对约束优化问题的研究综述 总被引:9,自引:0,他引:9
1 引言工程、数学等领域经常遇到大量的约束优化(或非线性规划)问题,需要对约束条件进行处理。目前,还没有一种通用的传统优化方法,能够处理各种类型的约束。相比,遗传算法(GA)在这一领域,比其它方法更有巨大优势和应用潜力。遗传算法的群体搜索策略和不依赖梯度信息的计算方式,使得它在处理约束优化问题时比传统搜索算法通用和有效。许多处理约束优化问题的传统算法都可以直接或改进后而用于GA。此外,由于GA是一种随机算法,既可以在编码时或设计遗传算子时加以考虑,也可以在每一代通过修正算法使所产 相似文献