求解大规模系统可靠性问题的修正和声搜索算法

针对大规模系统可靠性问题, 提出一种修正和声搜索(MHS) 算法. 该算法修改了和声搜索(HS) 算法的搜索机制, 以当前最优解为研究对象, 随机选取不同维数进行即兴创作, 并修正步长(BW) 的调整方式, 均衡算法的全局搜索和局部搜索. 对经典的大规模系统可靠性问题进行求解, 数值结果表明, 所提出算法优于其他文献中的6 种和声搜索算法. 与最近提出的求解此类问题的各种算法进行实验对比, 实验结果表明所提出算法在整体上具有良好的优化性能.

     

网络化切换控制系统故障检测与优化设计

研究存在未知短时延、丢包和系统不确定性的网络化切换控制系统故障检测与时域优化问题. 首先基 于观测器构建残差发生器, 结合Lyapunov 函数方法和平均驻留时间方法分析系统的稳定性, 并以线性矩阵不等式(LMI) 形式给出故障检测滤波器的求解方法; 然后为了改善故障检测系统的性能, 采用后置滤波器对残差信号进行时域优化, 并利用奇偶空间方法给出其最优解; 最后设计并推导出自适应阈值. 仿真结果验证了所提出方法的有效性.

     

基于改进教学算法优化BP 神经网络的催化剂碳含量预测模型

为提高待生催化剂碳含量预测的准确性, 提出一种基于改进的教学算法(MTLBO) 来优化BP 神经网络的预测模型. 针对基础教学算法全局搜索能力差的问题, 在教师阶段前后增加了预习和复习过程, 并在学生阶段采用量子方式进行更新. 测试结果表明, 该改进能够提高教学算法全局探索和局部改良能力, 利用改进教学算法可优化BP神经网络的权值和阈值, 并进行待生催化剂碳含量预测. 仿真结果表明, 改进后预测模型的预测精度和泛化能力均有一定程度的提高.

     

基于可信度阈值优化的案例推理评价分类方法

为了提高案例推理(CBR) 分类器的性能, 提出一种基于可信度阈值优化的CBR 评价分类方法. 首先, 通过一种可降低时间复杂度的改进型可信度评价策略对案例重用得到的建议解的可信度进行计算; 然后, 通过遗传算法(GA) 对可信度阈值进行迭代寻优; 接着, 根据得到的优化阈值将目标案例及其建议解划分为可信集或不可信集; 最后, 对不可信集按多数重用原则进行分类结论的调整, 从而实现可信的CBR 评价分类. 对比实验表明, 改进的可信度评价策略能有效提高分类性能, 从而可提高CBR分类器的决策与学习能力.

     

一种自适应全局和声搜索算法

针对新颖全局和声搜索(NGHS) 算法过早收敛的问题, 提出自适应全局和声搜索(AGHS) 算法. 引入差分向量范数定义和声记忆库多样性, 给出新的位置更新策略, 排除变异操作. 以和声记忆库多样性信息为指导动态产生新和声, 提高算法对解空间信息开发的能力, 避免算法因过早收敛、易陷入局部最优的不足. AGHS算法操作更简单,需要设置的参数更少, 将其与目前文献中较优的几种改进HS 算法、PSO 算法和GA算法进行性能测试, 测试结果表明AGHS算法具有较高的寻优精度和较快的收敛速度.

     

基于混合蛙跳与阴影集优化的粗糙模糊聚类算法

针对粗糙模糊聚类算法对初值敏感、易陷入局部最优和聚类性能依赖阈值选择等问题, 提出一种混合蛙跳与阴影集优化的粗糙模糊聚类算法(SFLA-SRFCM). 通过设置自适应调节因子, 以增加混合蛙跳算法的局部搜索能力; 利用类簇上、下近似集的模糊类内紧密度和模糊类间分离度构造新的适应度函数; 采用阴影集自适应获取类簇阈值. 实验结果表明, SFLA-SRFCM 算法是有效的, 并且具有更好的聚类精度和有效性指标.

     

求解多维背包问题的蚁群-拉格朗日松弛混合优化算法

针对多维背包问题(MKP) NP-hard、约束强的特点, 提出一种高效的蚁群-拉格朗日松弛(LR) 混合优化算法. 该算法以蚁群优化(ACO) 为基本框架, 并基于LR 对偶信息定义了一种MKP效用指标. ACO使得整体算法具有全局搜索能力, 所设计的效用指标将MKP的优化目标与约束条件有机地融合在一起. 该指标一方面可以用来定 义MKP核问题, 降低问题规模; 另一方面, 可以用作ACO的启发因子, 引导算法在有希望的解区域中强化搜索. 在大量标准算例上的测试结果表明, 所提出算法的鲁棒性较好; 与其他已有算法相比, 在求解质量和求解效率方面均具有很强的竞争力.

     

多目标资源优化分配问题的Memetic 算法

针对传统算法求解多目标资源优化分配问题收敛慢、Pareto解不能有效分布在Pareto 前沿面的问题, 提出一种新的Memetic 算法. 在遗传算法的交叉算子中引入模拟退火算法, 加强了遗传算法的局部搜索能力, 加快了收敛速度. 为了使Pareto 最优解均匀分布在Pareto 前沿面, 在染色体编码中引入禁忌表, 增加了种群的多样性, 避免了传统遗传算法后期Pareto 解集过于集中的缺点. 通过与已有的遗传算法、蚁群算法、粒子群算法进行比较, 仿真实验表明了所提出算法的有效性, 并分析了禁忌表长度和模拟退火参数对算法收敛性的影响.

     

存在未知时延和Markov 丢包的网络控制系统故障检测与优化

将网络控制系统(NCSs) 的未知短时延处理成范数有界不确定性, 结合Markov 丢包影响将NCSs 建模为不确定Markov 跳变系统, 设计模态依赖的鲁棒故障检测滤波器. 为了提高检测系统性能, 采用后置滤波器对残差信号进行时域优化, 并以Moore-Penrose 逆形式给出其最优解. 同时, 设计自适应检测阈值, 并给出时变参数阵的迭代方法,降低了计算量. 数值仿真表明, 所提出的方法能够有效地抑制时延和丢包影响, 提高故障检测系统的检测能力和检测速度.

     

基于DEPSO 的模糊时间ZW多产品厂间歇调度

研究以最小化完工时间为目标的模糊加工时间零等待多产品厂间歇调度问题, 提出一种基于差分进化粒子群优化(DEPSO) 的间歇调度算法. 以基本粒子群算法为整体进化框架, 采用基于反向学习的方法初始化种群, 引入群体极值保持代数作为阈值, 利用基于排序的差分进化算法优化粒子个体极值位置, 改变粒子的搜索范围, 防止粒子陷入局部极值. 仿真实验验证了所提算法在解决模糊加工时间零等待多产品厂间歇调度问题上的有效性和优越性.

     

An improved scheme for minimum cross entropy threshold selection based on genetic algorithm

Image segmentation is one of the most critical tasks in image analysis. Thresholding is definitely one of the most popular segmentation approaches. Among thresholding methods, minimum cross entropy thresholding (MCET) has been widely adopted for its simplicity and the measurement accuracy of the threshold. Although MCET is efficient in the case of bilevel thresholding, it encounters expensive computation when involving multilevel thresholding for exhaustive search on multiple thresholds. In this paper, an improved scheme based on genetic algorithm is presented for fastening threshold selection in multilevel MCET. This scheme uses a recursive programming technique to reduce computational complexity of objective function in multilevel MCET. Then, a genetic algorithm is proposed to search several near-optimal multilevel thresholds. Empirically, the multiple thresholds obtained by our scheme are very close to the optimal ones via exhaustive search. The proposed method was evaluated on various types of images, and the experimental results show the efficiency and the feasibility of the proposed method on the real images.     

Multilevel minimum cross entropy threshold selection based on the firefly algorithm

The minimum cross entropy thresholding (MCET) has been widely applied in image thresholding. The search mechanism of firefly algorithm inspired by the social behavior of the swarms of firefly and the phenomenon of bioluminescent communication, is used to search for multilevel thresholds for image segmentation in this paper. This new multilevel thresholding algorithm is called the firefly-based minimum cross entropy thresholding (FF-based MCET) algorithm. Four different methods that are the exhaustive search, the particle swarm optimization (PSO), the quantum particle swarm optimization (QPSO) and honey bee mating optimization (HBMO) methods are implemented for comparison with the results of the proposed method. The experimental results show that the proposed FF-based MCET algorithm can efficiently search for multiple thresholds which are very close to the optimal ones examined by the exhaustive search method when the number of thresholds is less than 5. The need of computation time of using the FF-based MCET algorithm is the least, meanwhile, the results using the FF-based MCET algorithm is superior to the ones of PSO-based and QPSO-based MCET algorithms but is not significantly different to the HBMO-based MCET algorithm.     

Human mental search-based multilevel thresholding for image segmentation

Multilevel thresholding is one of the principal methods of image segmentation. These methods enjoy image histogram for segmentation. The quality of segmentation depends on the value of the selected thresholds. Since an exhaustive search is made for finding the optimum value of the objective function, the conventional methods of multilevel thresholding are time-consuming computationally, especially when the number of thresholds increases. Use of evolutionary algorithms has attracted a lot of attention under such circumstances. Human mental search algorithm is a population-based evolutionary algorithm inspired by the manner of human mental search in online auctions. This algorithm has three interesting operators: (1) clustering for finding the promising areas, (2) mental search for exploring the surrounding of every solution using Levy distribution, and (3) moving the solutions toward the promising area. In the present study, multilevel thresholding is proposed for image segmentation using human mental search algorithm. Kapur (entropy) and Otsu (between-class variance) criteria were used for this purpose. The advantages of the proposed method are described using twelve images and in comparison with other existing approaches, including genetic algorithm, particle swarm optimization, differential evolution, firefly algorithm, bat algorithm, gravitational search algorithm, and teaching-learning-based optimization. The obtained results indicated that the proposed method is highly efficient in multilevel image thresholding in terms of objective function value, peak signal to noise, structural similarity index, feature similarity index, and the curse of dimensionality. In addition, two nonparametric statistical tests verified the efficiency of the proposed algorithm, statistically.     

基于TDMA方式WMN中一种链路调度机制研究

基于TDMA方式的无线网状网中,链路调度对网络性能起着重要作用.针对固定顺序的待调度链路集,提出求解最优调度周期的启发式算法;基于链路顺序对算法性能的影响,从全局优化的角度对全网链路进行排序,提出基于遗传算法的最优链路调度机制.仿真结果表明,该算法能快速收敛于全网链路的最小调度周期,具有比现有算法更高的传输效率和更低的实施复杂度.     

Multilevel thresholding selection based on the artificial bee colony algorithm for image segmentation

Multilevel thresholding is an important technique for image processing and pattern recognition. The maximum entropy thresholding (MET) has been widely applied in the literature. In this paper, a new multilevel MET algorithm based on the technology of the artificial bee colony (ABC) algorithm is proposed: the maximum entropy based artificial bee colony thresholding (MEABCT) method. Four different methods are compared to this proposed method: the particle swarm optimization (PSO), the hybrid cooperative-comprehensive learning based PSO algorithm (HCOCLPSO), the Fast Otsu’s method and the honey bee mating optimization (HBMO). The experimental results demonstrate that the proposed MEABCT algorithm can search for multiple thresholds which are very close to the optimal ones examined by the exhaustive search method. Compared to the other four thresholding methods, the segmentation results of using the MEABCT algorithm is the most, however, the computation time by using the MEABCT algorithm is shorter than that of the other four methods.     

A new social and momentum component adaptive PSO algorithm for image segmentation

In this paper, we present a new variant of Particle Swarm Optimization (PSO) for image segmentation using optimal multi-level thresholding. Some objective functions which are very efficient for bi-level thresholding purpose are not suitable for multi-level thresholding due to the exponential growth of computational complexity. The present paper also proposes an iterative scheme that is practically more suitable for obtaining initial values of candidate multilevel thresholds. This self iterative scheme is proposed to find the suitable number of thresholds that should be used to segment an image. This iterative scheme is based on the well known Otsu’s method, which shows a linear growth of computational complexity. The thresholds resulting from the iterative scheme are taken as initial thresholds and the particles are created randomly around these thresholds, for the proposed PSO variant. The proposed PSO algorithm makes a new contribution in adapting ‘social’ and ‘momentum’ components of the velocity equation for particle move updates. The proposed segmentation method is employed for four benchmark images and the performances obtained outperform results obtained with well known methods, like Gaussian-smoothing method (Lim, Y. K., & Lee, S. U. (1990). On the color image segmentation algorithm based on the thresholding and the fuzzy c-means techniques. Pattern Recognition, 23, 935–952; Tsai, D. M. (1995). A fast thresholding selection procedure for multimodal and unimodal histograms. Pattern Recognition Letters, 16, 653–666), Symmetry-duality method (Yin, P. Y., & Chen, L. H. (1993). New method for multilevel thresholding using the symmetry and duality of the histogram. Journal of Electronics and Imaging, 2, 337–344), GA-based algorithm (Yin, P. -Y. (1999). A fast scheme for optimal thresholding using genetic algorithms. Signal Processing, 72, 85–95) and the basic PSO variant employing linearly decreasing inertia weight factor.     

基于带特征染色体遗传算法的支持向量机特征选择和参数优化

鉴于支持向量机特征选择和参数优化对其分类准确率有重大的影响,将支持向量机渐近性能融入遗传算法并生成特征染色体,从而将遗传算法的搜索导向超参数空间中的最佳化误差直线.在此基础上,提出一种新的基十带特征染色体遗传算法的方法,同时进行支持向量机特征选择和参数优化.在与网格搜索、不带特征染色体遗传算法和其他方法的比较中,所提出的方法具有较高的准确率、更小的特征子集和更少的处理时间.     

非均匀多采样率非线性系统的模糊辨识

针对非均匀多采样率非线性系统辨识问题, 提出一种基于模糊模型的辨识方法. 首先, 分析了非线性系统在输入信号非均匀周期刷新, 输出信号周期采样的情况下, 非线性系统可以通过提升技术, 利用多个局部的线性模型加权组合来描述; 然后, 提出一个基于GK模糊聚类和递推最小二乘的模糊辨识算法; 最后, 针对化工pH 中和过程非线性系统, 采用非均匀采样数据建立其模糊模型, 以验证所提出方法的有效性.

     

一种智能优化算法解质量评价方法

如何评价智能优化算法在有限时间内所得解的质量, 是计算智能基础研究和工程实践中都亟待解决的问题. 受序优化思想启发, 针对连续优化问题, 提出一种评价智能优化算法解质量的方法. 首先利用聚类方法对解记录均匀化分区, 然后根据适应度值分布计算对准概率作为解质量评价指标. 通过对均匀采样、非均匀采样、粒子群算法和遗传算法的寻优结果进行实验表明了所提出方法的有效性.

     

动态适应布谷鸟搜索算法

介绍一种新的生物启发算法—–布谷鸟搜索(CS)及其相关的L′evy飞行搜索机制.为了进一步提高算法的适应性,将反馈引入算法框架,建立了CS算法参数的闭环控制系统.将Rechenberg的1/5法则作为进化的评价指标,引入学习因子平衡种群的多样性和集中性,提出动态适应布谷鸟算法(DACS).最后,通过数值实验验证了所提出算法的有效性.