A FORTRAN 90 genetic algorithm module for composite laminate structure design

The design of the stacking sequence for a composite laminate involves a set of discrete variables (plymaterial and ply orientation), and is thus well-suited to genetic algorithms for design optimization. Such algorithms have typically been custom-designed in FORTRAN 77 to suit specific optimization problems. Fortran 90 is a modern, powerful language with features that support important programming concepts, including those used in object-oriented programming. The Fortran 90 genetic algorithm module is used to define genetic data types, the functions which use these data types, and to provide a general framework for solving composite laminate structure design problems. The language's support of abstract data types is used to build genetic structures such as populations, subpopulations, individuals, chromosomes, and genes, and these data types are combined and manipulated by module subroutines. The use of abstract data types and long variable names makes the code useful and easily understood, while dynamic memory allocation makes the module flexible enough to be used in design problems of varying size and specification.     

混合流水车间调度的遗传下降算法

针对混合流水车间调度问题(Hybrid Flow Shop Scheduling,HFSS)建立了混合整数规 划模型,提出了遗传下降算法(Genetic Descent Algorithm,GDA).GDA与HFSS工件在机器上 最优分配规则相结合,不但能够产生初始可行解,而且保证交叉和变异后解仍然可行;同时在遗 传算法中嵌入邻域下降策略.为了验证GDA算法的有效性,随机产生了230组数据进行实验. 实验结果表明:对于HFSS问题,在小规模情况下,GDA算法与最优解之间的平均偏差为0.1%; 对于较大规模的情况,GDA比NEH算法平均改进10.45%.     

Multilayered neural architectures evolution for computing sequences of orthogonal polynomials

This article presents an evolutionary algorithm to autonomously construct full-connected multilayered feedforward neural architectures. This algorithm employs grammar-guided genetic programming with a context-free grammar that has been specifically designed to satisfy three important restrictions. First, the sentences that belong to the language produced by the grammar only encode all valid neural architectures. Second, full-connected feedforward neural architectures of any size can be generated. Third, smaller-sized neural architectures are favored to avoid overfitting. The proposed evolutionary neural architectures construction system is applied to compute the terms of the two sequences that define the three-term recurrence relation associated with a sequence of orthogonal polynomials. This application imposes an important constraint: training datasets are always very small. Therefore, an adequate sized neural architecture has to be evolved to achieve satisfactory results, which are presented in terms of accuracy and size of the evolved neural architectures, and convergence speed of the evolutionary process.     

基于量子遗传算法的XML聚类方法

主要用模式分析的核方法与量子遗传算法相结合研究XML聚类,提出了一种基于量子遗传算法混合核聚算法的XML文档聚类新方法。该方法先对XML文档约简,以频繁标签序列建立向量空间核的核矩阵,用高斯核函数求解初始聚类和聚类中心,然后用初始聚类中心构造量子遗传算法的初始种群,通过量子遗传算法与核聚算法相结合求得全局最优解的聚类。实验结果表明,使用该算法的聚类比改进的核聚算法、K均值算法等单一方法具有良好的收敛性、稳定性和更高的全局最优。     

基于均匀设计的遗传算法及其应用

本文为克服遗传算法解决有关优化问题时,对遗传算法的各操作参数及初始种群的选取往往凭借经验带有盲目性,还需要大量反复的试验才能获得比较理想的操作参数和初始种群的缺点,引入均匀试验设计的思想将遗传算法参数设定描述为一个多因素多水平的优化设计问题,应用均匀设计方法选取遗传算法操作参数和初始种群,对全维状态观测器设计的实例应用表明该方法简单有效,具有工程实用价值,为遗传算法的实际应用提供了科学指导。     

A novel approach to the placement and routing problems for field programmable gate arrays

This paper presents an artificial neural network (ANN) based parallel evolutionary solution to the placement and routing problems for field programmable gate arrays (FPGAs). The concepts of artificial neural networks are utilized for guiding the parallel genetic algorithm to intelligently transform a set of initial populations of randomly generated solutions to a final set of populations that contain solutions approximating the optimal one. The fundamental concept of this paper lies in capturing the various intuitive strategies of the human brain into neural networks, which may help the genetic algorithm to evolve its population in a more lucrative manner. A carefully chosen fitness function acts in the capacity of a yardstick to appraise the quality of each “chromosome” to aid the selection phase. In conjunction with the migration phase and the chosen fitness function various genetic operators are employed, to expedite the transformation of the initial population towards the final solution. The suggested algorithms have been implemented on a 12-node SGI Origin-2000 platform using the message passing interface (MPI) standard and the neural network utilities provided by MAT Lab software. The results obtained by executing the same are extremely encouraging, especially for circuits with very large number of nets.     

遗传算法在非线性规划中的应用

非线性规划问题是运筹学中的重要分支之一,广泛应用于各个领域。为了解决非线性规划问题的全局优化问题,该文提出利用具有学习算子的遗传算法来进行求解。实例结果表明,该算法具有良好的求解效果。     

遗传算法在非线性规划中的应用

非线性规划问题是运筹学中的重要分支之一，广泛应用于各个领域。为了解决非线性规划问题的全局优化问题．该文提出利用具有学习算子的遗传算法来进行求解。实例结果表明，该算法具有良好的求解效果。     

A genetic algorithm with genes-association recognition for flowshop scheduling problems

In this paper, we consider a flowshop scheduling problem with a special blocking RCb (Release when Completing Blocking). This flexible production system is prevalent in some industrial environments. Genetic algorithms are first proposed for solving these flowshop problems and different initial populations have been tested to find which is best adapted. Then, a method is proposed for further improving genetic algorithm found solutions, which consists in marking out recurrent genes association occurrences in an already genetic algorithm optimized population. This idea directly follows Holland’s first statement about nature observations. Here, proposed idea is that populations well adapted to a problem have an adapted genetic code with common properties. We propose to mark out these properties in available genetic code to further improve genetic algorithm efficiency. Implementation of this method is presented and obtained results on flowshop scheduling problems are discussed.     

一种求解TSP初始化种群问题的方法

为提升求解TSP问题的计算效率和求解精度,针对初始种群构造问题进行研究,提出了域内三角概率选择自适应邻域算法。为使邻域半径能够适应城市的分布情况,设计了一种基于Sigmoid函数的邻域半径自适应函数;为了避免在邻域内盲目随机地选择下一站城市,提出了在邻域内利用三角概率选择模型选择下一个城市。以自动化立体仓库安排出入库作业顺序优化作为TSP研究问题,通过Matlab仿真计算,将该算法和邻域法生成的初始种群进行对比分析,并分别用该算法和随机生成的初始种群作为遗传算法的初始种群进行计算。证明了该算法可快速生成高质量的初始种群,大大提升了求解TSP问题的计算效率和求解精度。     

基于混合蛙跳和遗传规划的跨单元调度方法

针对运输能力受限条件下的跨单元问题,提出了一种基于混合蛙跳与遗传规划的超启发式算法.将改进的混合蛙跳算法作为超启发式算法的高层框架,为跨单元调度问题搜索启发式规则,同时利用遗传规划产生可以兼顾多因素的优质规则,用于扩充超启发式算法的规则集.实验表明,提出的算法可以有效地搜索出优异的规则组合,并且通过遗传规划产生的规则可以在很大程度上改善候选规则集,提升算法性能.     

多级生产批量规划问题的柔性惯量反捕食粒子群算法

多级生产批量规划(MLLS)是原料需求计划(MRP)中主生产计划(MPS)的关键决策问题,具有广泛的工业应用;已被证明是NP-hard类型的组合优化问题.反捕食粒子群算法(APSO)是最近提出的一种与粒子群算法(PSO)密切相关的亚启发式算法.本文提出带柔性惯性权重的反捕食粒子群算法(WAPSO)对具有指定装配结构而无约束的MLLS问题进行了求解.本算法对12个小规模benchmark数据集和1个随机产生的较大规模数据进行了测试.测试结果与遗传算法(GA)和Wagner-Whitin(WW)动态规划算法的结果进行了比较.结果表明了WAPSO算法的有效性和适用性.     

基于遗传算法的最优化问题求解

遗传算法是一种有效的解决最优化问题的方法,在解决复杂的全局优化问题方面,遗传算法已得到了成功的应用。对遗传算法的基本步骤进行总结,通过最优化问题求解实例描述了遗传算法的具体运行过程,包括产生初始染色体、染色体评价、选择、交叉、变异等。分别应用VC和VB两种语言进行编程实现,结果表明,VC语言在运算效率和结果优度方面均比VB语言要好。     

Population variation in genetic programming

A new population variation approach is proposed, whereby the size of the population is systematically varied during the execution of the genetic programming process with the aim of reducing the computational effort compared with standard genetic programming (SGP). Various schemes for altering population size under this proposal are investigated using a comprehensive range of standard problems to determine whether the nature of the “population variation”, i.e. the way the population is varied during the search, has any significant impact on GP performance. The initial population size is varied in relation to the initial population size of the SGP such that the worst case computational effort is never greater than that of the SGP. It is subsequently shown that the proposed population variation schemes do have the capacity to provide solutions at a lower computational cost compared with the SGP.     

Multi-objective vehicle routing problem with time windows using goal programming and genetic algorithm

This paper presents a new model and solution for multi-objective vehicle routing problem with time windows (VRPTW) using goal programming and genetic algorithm that in which decision maker specifies optimistic aspiration levels to the objectives and deviations from those aspirations are minimized. VRPTW involves the routing of a set of vehicles with limited capacity from a central depot to a set of geographically dispersed customers with known demands and predefined time windows. This paper uses a direct interpretation of the VRPTW as a multi-objective problem where both the total required fleet size and total traveling distance are minimized while capacity and time windows constraints are secured. The present work aims at using a goal programming approach for the formulation of the problem and an adapted efficient genetic algorithm to solve it. In the genetic algorithm various heuristics incorporate local exploitation in the evolutionary search and the concept of Pareto optimality for the multi-objective optimization. Moreover part of initial population is initialized randomly and part is initialized using Push Forward Insertion Heuristic and λ-interchange mechanism. The algorithm is applied to solve the benchmark Solomon's 56 VRPTW 100-customer instances. Results show that the suggested approach is quiet effective, as it provides solutions that are competitive with the best known in the literature.     

A data mining approach to discover genetic and environmental factors involved in multifactorial diseases

In this paper, we are interested in discovering genetic and environmental factors that are involved in multifactorial diseases. Experiments have been achieved by the Biological Institute of Lille and many data has been generated. To exploit these data, data mining tools are required and we propose a two-phase optimisation approach using a specific genetic algorithm. During the first step, we select significant features with a specific genetic algorithm. Then, during the second step, we cluster affected individuals according to the features selected by the first phase. The paper describes the specificities of the genetic problem that we are studying, and presents in detail the genetic algorithm that we have developed to deal with this very large size feature selection problem. Results on both artificial and real data are presented.     

Effects of code growth and parsimony pressure on populations in genetic programming

Parsimony pressure, the explicit penalization of larger programs, has been increasingly used as a means of controlling code growth in genetic programming. However, in many cases parsimony pressure degrades the performance of the genetic program. In this paper we show that poor average results with parsimony pressure are a result of "failed" populations that overshadow the results of populations that incorporate parsimony pressure successfully. Additionally, we show that the effect of parsimony pressure can be measured by calculating the relationship between program size and performance within the population. This measure can be used as a partial indicator of success or failure for individual populations.     

Locating input and output points in facilities design - acomparison of constructive, evolutionary, and exact methods

This paper formulates and compares four new approaches to optimally locate the input and output station for each department within a facility design such that material handling costs are minimized. This problem is an NP-hard combinatorial problem with many real-life applications of considerable economic consequence. A genetic algorithm (GA) is shown to be an effective and efficient optimization method when compared to integer programming, simulated annealing, and three versions of a greedy constructive heuristic on a suite of test problems of varying size. Seeding versus random initialization of GA populations are compared     

数据仓库中用于视图选择的增强遗传算法

物化视图选择问题是数据仓库设计中最重要的问题之一,为了高效地解决这一问题.提出了一个如何选择物化视图集的增强遗传算法,以便在存储空间约束的条件下,取得较好的查询性能和较低的视图维护代价.这一算法的核心思想在于,首先,运用一个基于单位空间最大收益值的预处理算法来生成初始解,然后,该初始解经采用了多种优化策略的遗传算法进行提高,这些优化策略包括:基于改进的锦标赛和精英选择相结合的选择算子、基于半均匀交叉算子及自适应变异算子.并且,在进化过程中产生的无效解用损失函数加以修补.试验结果表明,该算法在寻优性能上优于启发式算法和经典遗传算法.