高维多目标进化算法研究综述

传统的多目标进化算法能够有效地解决2个或3个目标的优化问题,但当优化目标超过4维即具有高维目标时,其优化效果将大大下降,因此高维多目标进化算法的研究得到了较多的关注.鉴于此,对高维多目标进化算法的研究进展进行系统地分类综述,分析了高维目标对优化算法造成的困难以及改进的可视化技术;总结了各类算法的特点与缺陷,并给出进一步可能的研究方向.     

优化设计中的多目标进化算法

近十多年来多目标进化算法是人工智能领域的一个相当活跃的研究热点。该文从非Pareto方法、基于Pareto方法及贝叶斯多目标优化算法等角度对当今多目标进化算法进行了分析,归纳了新出现的各种方法和技术,探讨了这个领域发展中存在的问题,并进一步给出了发展方向。此外文中分别对后两类提出了解决一般问题的计算效果较好的改进算法和新的算法。     

进化多目标优化算法研究

进化多目标优化主要研究如何利用进化计算方法求解多目标优化问题,已经成为进化计算领域的研究热点之一.在简要总结2003年以前的主要算法后,着重对进化多目标优化的最新进展进行了详细讨论.归纳出当前多目标优化的研究趋势,一方面,粒子群优化、人工免疫系统、分布估计算法等越来越多的进化范例被引入多目标优化领域,一些新颖的受自然系统启发的多目标优化算法相继提出;另一方面,为了更有效的求解高维多目标优化问题,一些区别于传统Pareto占优的新型占优机制相继涌现;同时,对多目标优化问题本身性质的研究也在逐步深入.对公认的代表性算法进行了实验对比.最后,对进化多目标优化的进一步发展提出了自己的看法.     

多目标优化的演化算法

近年来．多目标优化问题求解已成为演化计算的一个重要研究方向，而基于Pareto最优概念的多目标演化算法则是当前演化计算的研究热点．多目标演化算法的研究目标是使算法种群快速收敛并均匀分布于问题的非劣最优域．该文在比较与分析多目标优化的演化算法发展的历史基础上，介绍基于Pareto最优概念的多目标演化算法中的一些主要技术与理论结果，并具体以多目标遗传算法为代表，详细介绍了基于偏好的个体排序、适应值赋值以及共享函数与小生境等技术．此外，指出并阐释了值得进一步研究的相关问题．     

多目标优化演化算法研究综述

演化计算来源于自然界进化过程的灵感和进化思想的观点。它的潜在并行性及自组织、自适应、自学习的智能特性对于求解多目标优化问题具有巨大的潜力。系统地介绍多目标进化算法（MOEAs）,同时讨论进化算法（EAs）在多目标优化应用中的几个关键性问题及今后需进一步研究的工作,并做总结和展望。     

多目标进化算法研究进展

进化算法具有本质上并行、不需要求导或其他辅助知识、一次运行产生多个解和简单易于实现等优点,被视为求解多目标优化问题的有效方法,目前已经形成了各种不同的多目标进化算法（MOEA）。本文首先回顾了多目标进化算法的研究起源,给出了多目标优化问题的数学描述;其次,详细分析了第一代多目标进化算法,其主要特征是简单易于实现,包括NSGA、NPGA、MOGA等,并指出这一代算法研究的成绩与不足;然后,对第二代多目标进化算法作了全面分析,指出其特征是强调效率,以精英保留策略为实现机制,且对SPEA、PAES、NSGAⅡ、NPGA2、PESA、Micro-GA等方法进行分析比较,还对这一代的研究作了总结;最后,对多目标进化算法的研究趋势作了展望和预测。     

多目标演化算法的进展研究

回顾多目标演化算法的研究历史,给出问题相应的数学描述;其次,分析经典的第一代多目标进化算法,阐明这一代算法的优点与不足;对新一代多目标进化算法作详细的分析,其主要特点是构造外部种群实现精英保留机制;最后多目标进化算法的研究方向作展望.     

多目标进化算法性能评价指标研究综述

多目标进化算法根据性能评价指标衡量其优劣,主要从算法所求解集的质量、算法求解效率以及算法鲁棒性三方面来评价,并侧重于解集的质量,现有的相关工作缺乏对评价指标数学性质的分析.本文将评价指标按性能标准分为四类:计数指标、收敛性指标、多样性指标、综合性指标,其中计数指标统计符合指标要求的解个数或比例,收敛性指标衡量解集与参考...     

Evolutionary Algorithms for Multi-Objective Optimization: Performance Assessments and Comparisons

Evolutionary techniques for multi-objective(MO) optimization are currently gainingsignificant attention from researchers invarious fields due to their effectiveness androbustness in searching for a set of trade-offsolutions. Unlike conventional methods thataggregate multiple attributes to form acomposite scalar objective function,evolutionary algorithms with modifiedreproduction schemes for MO optimization arecapable of treating each objective componentseparately and lead the search in discoveringthe global Pareto-optimal front. The rapidadvances of multi-objective evolutionaryalgorithms, however, poses the difficulty ofkeeping track of the developments in this fieldas well as selecting an existing approach thatbest suits the optimization problem in-hand.This paper thus provides a survey on variousevolutionary methods for MO optimization. Manywell-known multi-objective evolutionaryalgorithms have been experimented with andcompared extensively on four benchmark problemswith different MO optimization difficulties.Besides considering the usual performancemeasures in MO optimization, e.g., the spreadacross the Pareto-optimal front and the abilityto attain the global trade-offs, the paper alsopresents a few metrics to examinethe strength and weakness of each evolutionaryapproach both quantitatively and qualitatively.Simulation results for the comparisons areanalyzed, summarized and commented.     

多目标进化算法测试问题的设计与分析

为了有效检测多目标优化进化算法的性能,从3个方面进行多目标优化测试问题的设计,即约束条件、最优解分布的均匀性、算法逼近Pareto最优前沿的难度,采用NSGA-Ⅱ算法对这些测试问题进行仿真实验,并将算法求得的最优解可视化。结果显示,测试问题能够有效检测算法在上述3方面的性能。     

三维微阵列数据的多目标进化聚类

聚类技术广泛应用于微阵列数据分析中。在基因-样本-时间GST微阵列数据矩阵中,挖掘三雏聚类成为当前的热门研究课题。3D聚类过程经常需要对多个相互冲突的目标进行优化,而且进化算法以其强大的探寻能力成为高维搜索空间中非常有效的搜索方法。本文基于多目标进化计算方法提出一个新的3D聚类算法MOE-TC,以挖掘GST数据中的3D聚类。现实微阵列数据上的实验验证结果充分说明了本文算法的有效性。     

Integrating Conjugate Gradients Into Evolutionary Algorithms for Large-Scale Continuous Multi-Objective Optimization

Large-scale multi-objective optimization problems (LSMOPs) pose challenges to existing optimizers since a set of well-converged and diverse solutions should be found in huge search spaces. While evolutionary algorithms are good at solving small-scale multi-objective optimization problems, they are criticized for low efficiency in converging to the optimums of LSMOPs. By contrast, mathematical programming methods offer fast convergence speed on large-scale single-objective optimization problems, but they have difficulties in finding diverse solutions for LSMOPs. Currently, how to integrate evolutionary algorithms with mathematical programming methods to solve LSMOPs remains unexplored. In this paper, a hybrid algorithm is tailored for LSMOPs by coupling differential evolution and a conjugate gradient method. On the one hand, conjugate gradients and differential evolution are used to update different decision variables of a set of solutions, where the former drives the solutions to quickly converge towards the Pareto front and the latter promotes the diversity of the solutions to cover the whole Pareto front. On the other hand, objective decomposition strategy of evolutionary multi-objective optimization is used to differentiate the conjugate gradients of solutions, and the line search strategy of mathematical programming is used to ensure the higher quality of each offspring than its parent. In comparison with state-of-the-art evolutionary algorithms, mathematical programming methods, and hybrid algorithms, the proposed algorithm exhibits better convergence and diversity performance on a variety of benchmark and real-world LSMOPs.      

Octree-Related Data Structures and Algorithms

The octree is not always a desirable data structure. Here, together with their formal definitions and related algorithms, are two data structures more suitable for graphics operations.     

SSD数据结构与算法综述

SSD（Solid State Disk）是一种基于闪存的电可擦除可编程的新型存储器件。与普通硬盘相比,SSD具有访问延迟小、低功耗等优点。但SSD的应用也需要解决写前擦除、损耗平衡等挑战。针对这些挑战,工业界和学术界研究提出了多种复杂的算法和数据结构。对这些研究成果进行了分析和综述,同时探讨了SSD在分层存储中的应用。     

基于Delaunay三角剖分的多目标进化算法解集分布度评价指标

系统分析目前多目标进化算法(MOEAs)分布度评价指标的特点和不足,提出一种基于Delaunay三角剖分的分布度评价指标。该指标将基于邻域和基于距离的评价思想相结合,利用Delaunay三角网最近邻与邻接性的特点实现自主邻域划分。采用空间映射的方法,有效减少MOEAs解集非支配关系对种群分布度评价的影响。测试结果表明该指标能准确反映MOEAs解集的分布性。     

A Survey of Evolutionary Algorithms for Multi-Objective Optimization Problems With Irregular Pareto Fronts

Evolutionary algorithms have been shown to be very successful in solving multi-objective optimization problems(MOPs).However,their performance often deteriorates when solving MOPs with irregular Pareto fronts.To remedy this issue,a large body of research has been performed in recent years and many new algorithms have been proposed.This paper provides a comprehensive survey of the research on MOPs with irregular Pareto fronts.We start with a brief introduction to the basic concepts,followed by a summary of the benchmark test problems with irregular problems,an analysis of the causes of the irregularity,and real-world optimization problems with irregular Pareto fronts.Then,a taxonomy of the existing methodologies for handling irregular problems is given and representative algorithms are reviewed with a discussion of their strengths and weaknesses.Finally,open challenges are pointed out and a few promising future directions are suggested.     

Evolutionary Algorithms for Allocating Data in Distributed Database Systems

A major cost in executing queries in a distributed database system is the data transfer cost incurred in transferring relations (fragments) accessed by a query from different sites to the site where the query is initiated. The objective of a data allocation algorithm is to determine an assignment of fragments at different sites so as to minimize the total data transfer cost incurred in executing a set of queries. This is equivalent to minimizing the average query execution time, which is of primary importance in a wide class of distributed conventional as well as multimedia database systems. The data allocation problem, however, is NP-complete, and thus requires fast heuristics to generate efficient solutions. Furthermore, the optimal allocation of database objects highly depends on the query execution strategy employed by a distributed database system, and the given query execution strategy usually assumes an allocation of the fragments. We develop a site-independent fragment dependency graph representation to model the dependencies among the fragments accessed by a query, and use it to formulate and tackle data allocation problems for distributed database systems based on query-site and move-small query execution strategies. We have designed and evaluated evolutionary algorithms for data allocation for distributed database systems.     

数据结构和算法的可视化教学研究与实践

本文介绍和总结了数据结构和算法的可视化ＣＡＩ软件的开发应用，并对已形成的数据结构课程的全面可视化ＣＡＩ教学模式进行了初步的探讨。     

Interleaving Guidance in Evolutionary Multi-Objective Optimization

In this paper, we propose a framework that uses localization for multi-objective optimization to simultaneously guide an evolutionary algorithm in both the decision and objective spaces. The localization is built using a limited number of adaptive spheres （local models） in the decision space. These spheres axe usually guided, using some direction information, in the decision space towards the areas with non-dominated solutions. We use a second mechanism to adjust the spheres to specialize on different parts of the Paxeto front by using a guided dominance technique in the objective space. Through this interleaved guidance in both spaces, the spheres will be guided towards different parts of the Paxeto front while also exploring the decision space efficiently. The experimental results showed good performance for the local models using this dual guidance, in comparison with their original version.