参数选取对遗传算法动力学形态的影响

遗传算法中参数的选取决定遗传算法的运行性能．目前,对算法中参数选取都是经验性的．本文针对一个典型的2-bit问题,分析了在不同参数选取下GA的全局动力学形态．通过对标准遗传算法的各种参数的选取,分别建立了数学模型．分析了这些模型的吸引子,揭示了不同参数对动力学形态的影响．世代重叠模型和无参数模型的动力学形态相似．当变异概率很小时,模型与没有变异算子相类似;当变异算子足够大时,模型的动力学形态随着变异概率的增加发生了突变．原有的吸引不动点消失,原来的排斥不动点变成吸引不动点．这些论证为遗传算法中参数选取提供了一些理论上的证据．     

神舟三号飞船搭载水稻种子M1代变化的分析

为研究空间环境处理对水稻生长发育的影响,筛选有益的突变体,在神舟三号飞船上搭载10个不同熟期水稻品种的干种子．种子返地后栽培,考察发芽率、分蘖数和抽穗期等性状,并进行显著性分析．结果表明空间环境对不同基因型品种的分蘖有刺激和抑制两种效应,不同熟期的品种抽穗期变化的方向与基因型有关．空间处理M1代亦出现5株株高变高的个体,其生物学性状与对照有明显差异．     

基于免疫的并行单亲遗传算法研究

在分析了单亲遗传算法的优越性与存在不足的基础上，借鉴生物免疫概念与理论并结合并行计算的思想，提出了一种新的遗传算法——基于免疫的并行单亲遗传算法。理论分析和仿真结果表明，该算法不仅能够有效地保持群体多样性，而且减轻了遗传算法后期的波动现象，同时收敛速度有明显的提高。     

粒子群优化算法的改进及其实现

基本粒子群优化算法存在着"早熟"现象。究其主要原因是由于全局最优粒子的运动形式滞留在局部最优。为此,根据基本PSO算法的特点,在粒子运动过程中加入了个体小概率随机变异,增强了粒子运动形式改变能力,减小了陷入局部最优的可能性。通过数值计算结果表明,该方法能有效地解决粒子群优化"早熟"问题。     

基于改进粒子群优化算法的电力系统无功电压综合控制

在基本粒子群优化算法的基础上,提出了一种改进的粒子群优化算法用于电力系统无功电压综合控制。该算法改进了随机初始化种群的方法,采用均匀初始化,引进了粒子的自身探索机制,用多个位于可行域中的粒子个体引导粒子的更新,以保证全局搜索的有效性,同时采用混沌变异算子对陷入局部最优的粒子进行变异,提高了算法的寻优性能。通过对IEEE-30节点标准系统模型的无功电压综合控制计算和分析,证明了此改进的粒子群优化算法具有更高的全局寻优效率。     

自适应免疫遗传算法及其在区域电力系统最优备用容量计算中的应用

充分利用区域互联电力系统在紧急情况下可以互相支援互为备用的特点,建立了区域电力系统的最优备用容量数学模型,该模型采用基于最小发电成本函数和最小网损函数组成的归一化最小综合经济成本作为目标函数。针对问题的具体特点,运用自适应免疫遗传算法求解最优备用容量,利用图论中的最大支撑树概念,采用自动产生可行解的编码策略对染色体进行编码,以及交叉、变异概率的自适应选取,在IEEE30节点测试系统上的仿真结果验证了所提模型的合理性、所提方法的可行性。     

A novel micro-population immune multiobjective optimization algorithm

In this paper, we present a novel immune multiobjective optimization algorithm based on micro-population, which adopts a novel adaptive mutation operator for local search and an efficient fine-grained selection operator for archive update. With the external archive for storing nondominated individuals, the population diversity can be well preserved using an efficient fine-grained selection procedure performed on the micro-population. The adaptive mutation operator is executed according to the fitness values, which promotes to use relatively large steps for boundary and less-crowded individuals in high probability. Therefore, the exploratory capabilities are enhanced. When comparing the proposed algorithm with a recently proposed immune multiobjective algorithm and a scatter search multiobjective algorithm in various benchmark functions, simulations show that the proposed algorithm not only improves convergence ability but also preserves population diversity adequately in most cases.     

THE CASE FOR REVERSE TRANSLATION

The case for “reverse translation” is briefly presented. The manifest problems in immunology in accounting for antibody diversity and the dependence of DNA mutation on cellular processes plus, on the theoretical side, the cybernetic necessity of abstracting environmental information in order to maintain relevant genetic material together give weight to a search for this reverse process. Mekler's 1967 reverse translation theory is outlined and shown not to be objectionable either in terms of known biochemical reactions or in terms of the assertion of the “central dogma” that macro-molecular information does not “flow out” of the proteins once it has “flowed in”.     

Defining a test coverage criterion for model-level testing of FBD programs

ContextThe Programmable Logic Controller (PLC) is being integrated into the automation and control of computer systems in safety–critical domains at an increasing rate. Thoroughly testing such software to ensure safety is crucial. Function Block Diagram (FBD) is a popular data-flow programming language for PLC. Current practice often involves translating an FBD program into an equivalent C program for testing. Little research has been conducted on coverage of direct testing a data-flow program, such as an FBD program, at the model level. There are no commonly accepted structural test coverage criteria for data-flow programs. The objective of this study is to develop effective structural test coverage criterion for testing model-level FBD programs. The proposed testing scheme can be used to detect mutation errors at the logical function level.ObjectiveThe purpose of this study is to design a new test coverage criterion that can directly test FBD programs and effectively detect logical function mutation errors.MethodA complete test set for each function and function block in an FBD program are defined. Moreover, this method augments the data-flow path concept with a sensitivity check to avoid fault masking and effectively detect logical function mutation errors.ResultsPreliminary experiments show that this test coverage criterion is comprehensive and effective for error detection.ConclusionThe proposed coverage criterion is general and can be applied to real cases to improve the quality of data-flow program design.     

鄱阳湖入江径流变化规律及成因分析

为了深入认识鄱阳湖入江流量变化规律,采用多种水文分析方法,研究了湖口水文站1950~2012年径流、洪季径流、枯季径流、年最大流量和枯季最小流量的变化趋势、随机性、突变性和周期性。结果表明,枯季最小流量序列存在显著的增加趋势,其余序列变化趋势不明显;入江径流年内分配趋于均匀、集中度减小。洪季丰枯交替频率高于枯季,年最大流量与枯季最小流量的变化波动尺度比较接近。