Learning experiments with genetic optimization of a generalized regression neural network

This paper reports a study unifying optimization by genetic algorithm with a generalized regression neural network. Experiments compare hill-climbing optimization with that of a genetic algorithm, both in conjunction with a generalized regression neural network. Controlled data with nine independent variables are used in combination with conjunctive and compensatory decision forms, having zero percent and 10 percent noise levels. Results consistently favor the GRNN unified with the genetic algorithm.     

Meta-modeling using generalized regression neural network and particle swarm optimization

Swarm intelligence (SI) and evolutionary computation (EC) algorithms are often used to solve various optimization problems. SI and EC algorithms generally require a large number of fitness function evaluations (i.e., higher computational requirements) to obtain quality solutions. This requirement becomes more challenging when optimization problems are associated with computationally expensive analyses and/or simulation tasks. To tackle this issue, meta-modeling has shown successful results in improving computational efficiency by approximating the fitness or constraint functions of these complex optimization problems. Meta-modeling approaches typically use polynomial regression, kriging, radial basis function network, and support vector machines. Less attention has been given to the generalized regression neural network approach, and yet, it offers several advantages. Specifically, the model construction process does not require iterations. Its only one parameter is known to be less sensitive and usually requires less effort in selecting an optimal parameter. We use generalized regression neural network in this paper to construct meta-models and to approximate the fitness function in particle swarm optimization. To assess the performance and quality of these solutions, the proposed meta-modeling approach is tested on ten benchmark functions. The results are promising in terms of the solution quality and computational efficiency, especially when compared against the results of particle swarm optimization without meta-modeling and several other meta-modeling methods in previously published literature.     

Predicting lightning outages of transmission lines using generalized regression neural network

Lightning is the major cause of transmission line outages, which can result in large area blackouts of power systems. One effective method to prevent catastrophic consequences is to predict lightning outages before they occur. The abundance of recorded lightning and lightning outage data in power system makes it possible to predict lightning outages of transmission lines. This paper proposes an artificially intelligent algorithm using general regression neural networks (GRNN) to predict lightning outages of transmission lines. First, the data that can be obtained from the operation and management system of a power company are analyzed, and the features that can be used as input parameters of GRNN are extracted. The prediction model based on GRNN is then built to perform lightning outage prediction. Finally, the effectiveness of the proposed method is validated by comparing it with (Back Propagation) BP and (Radial Basis Function) RBF neural networks using actual lightning data and lightning outage data. The simulation results show that the proposed method provides much better prediction performance.     

一种基于代数算法的RBF神经网络优化方法

提出了一种新的RBF神经网络的训练方法,采用动态K-均值方法对RBF 神经网络的隐层中心值和宽度进行了优化,用代数算法训练隐层和输出层之间的权值。在对非线性函数进行逼近的仿真中,验证了该算法的有效性。     

基于自适应递阶遗传算法的神经网络优化策略

基于递阶结构的遗传算法可以同时对多层前向神经网络进行结构优化和权重求解。与基本的遗传算法相比，这种算法不仅在权重训练方面更加快速稳定，而且能在学习过程中确定网络的拓扑结构，具有较高的学习效率，而在遗传过程中采用自适应的交叉和变异概率能有效加快遗传速度和避免早熟现象的出现。     

利用影响因子遗传算法优化前馈神经网络

提出了一种带有影响因子的改进遗传算法并以此来优化前馈神经网络.染色体的每个基因都有一个影响因子,其不同取值体现了基因对整条染色体的不同影响程度.在遗传进化过程中,通过影响因子等遗传操作以达到对前馈神经网络的权值、阈值和结构优化的目的.仿真实验表明,该算法能够快速地确定神经网络的结构并且有效地提高了神经网络的收敛速度.     

用于电磁兼容预测的自适应泛化回归神经网络

为了更好地对电磁兼容进行预测,提出一种自适应泛化回归神经网络（AGRNN）,与传统泛化回归神经网络（GRNN）区别在于：将光滑因子设为最小数据距离的1/2,将偏置设为光滑因子的倒数。对简单一维数据的测试表明,无论数据如何分布,AGRNN的拟合曲线均较GRNN更加接近样本点、且更平滑。以平行线间电磁耦合干扰为具体算例,证明AGRNN对训练数据与测试数据的预测优于改进BP算法,且网络不需要训练。     

Flood simulation using parallel genetic algorithm integrated wavelet neural networks

The conventional means of flood simulation and prediction using conceptual hydrological model or artificial neural network (ANN) has provided promising results in recent years. However, it is usually difficult to obtain ideal flood reproducing due to the structure of hydrological model. Back propagation (BP) algorithm of ANN may also reach local optimum when training nodal weights. To improve the mapping capability of neural networks, wavelet function was adopted (WANN) to strengthen the non-linear simulation accuracy and generality. In addition, genetic algorithm is integrated with WANN (GAWANN) to avoid reaching local optimum. Meanwhile, Message Passing Interface (MPI) subroutines are introduced for distributed implement considering the time consumption during nodal weights training. The GAWANN was applied in the flood simulation and prediction in arid area. The test results of 4 independent cases were compared to reveal the relations between historical rainfall and runoff under different time lags. The simulation was also carried out with Xinanjiang model to demonstrate the capability of GAWANN. The numerical experiments in this paper indicated that the parallel GAWANN has strong capability of rain-runoff mapping as well as computational efficiency and is suitable for applications of flood simulation in arid areas.     

Incorporation of prior knowledge in neural network model for continuous cooling of steel using genetic algorithm

Artificial neural network model is developed for the prediction of phase transformation of steel from austenite, and thus construction of the continuous cooling transformation (CCT) diagram. The model for prediction of transformation temperatures from steel composition is developed using data from published CCT diagrams. The trained network sometimes fails to predict the sequence of the phase transformation, contradicting the fundamentals of metallurgy. To avoid such limitations of data driven models and to make the models truthful and reasonable from metallurgical standpoint, prior knowledge is incorporated using genetic algorithm, through modifying the weights and biases of a trained neural network. The conventionally backpropagated multi-layered perceptron is modified from error minimization as well as knowledge incorporation point of view through formulation of the problem in both single and multi-objective optimization domains. The predictions of six transformation temperatures by the new models are found to be significantly better than the conventionally trained model.     

基于广义回归神经网络的传感器非线性误差校正

介绍了径向基函数网络的函数逼近原理和方法,提出了一种基于广义回归神经网络(GRNN)的传感器非线性误差校正方法。通过Matlab的Network Toolbox(神经网络工具箱),GRNN训练程序实现了输出特性曲线逼近。仿真分析表明:GRNN能够很好地满足传感器非线性拟合的要求,网络结构简单,收敛速度快。     

基于遗传算法的BP神经网络技术的应用

针对BP网络的不足,提出了基于遗传算法的神经网络技术。将两者有机的融合在一起,充分利用了GA算法的全局搜索能力和BP算法的局部搜索能力,加快了收敛速度,提高了收敛精度,将其应用于高速公路动态称重系统的神经网络控制器的训练中,取得了较好的效果。     

Optimization of neural network model using modified bat-inspired algorithm

The success of an artificial neural network (ANN) strongly depends on the variety of the connection weights and the network structure. Among many methods used in the literature to accurately select the network weights or structure in isolate; a few researchers have attempted to select both the weights and structure of ANN automatically by using metaheuristic algorithms. This paper proposes modified bat algorithm with a new solution representation for both optimizing the weights and structure of ANNs. The algorithm, which is based on the echolocation behaviour of bats, combines the advantages of population-based and local search algorithms. In this work, ability of the basic bat algorithm and some modified versions which are based on the consideration of the personal best solution in the velocity adjustment, the mean of personal best and global best solutions through velocity adjustment and the employment of three chaotic maps are investigated. These modifications are aimed to improve the exploration and exploitation capability of bat algorithm. Different versions of the proposed bat algorithm are incorporated to handle the selection of the structure as well as weights and biases of the ANN during the training process. We then use the Taguchi method to tune the parameters of the algorithm that demonstrates the best ability compared to the other versions. Six classifications and two time series benchmark datasets are used to test the performance of the proposed approach in terms of classification and prediction accuracy. Statistical tests demonstrate that the proposed method generates some of the best results in comparison with the latest methods in the literature. Finally, our best method is applied to a real-world problem, namely to predict the future values of rainfall data and the results show satisfactory of the method.     

基于神经网络和遗传算法的组播路由算法

提出了一种基于神经网络和遗传算法的新颖的QoS组播路由算法, 该路由算法把神经网络和遗传算法结合起来,并给出了一种非常便于进行交叉、变异等遗传操作的新编码方式。从而克服了传统遗传算法中存在的早熟现象, 加快了收敛速度。仿真结果显示,算法在收敛速度方面要优于单纯的遗传算法和神经网络方法。     

基于伪并行混合遗传算法的神经网络优化

在分析并行多物种遗传算法应用于神经网络拓扑结构的设计和学习之后,提出一种伪并行遗传（PPGA-MBP）混合算法,结合改进的BP算法对多层前馈神经网络的拓扑结构进行优化。算法编码采用基于实数的层次混合方式,允许两个不同结构的网络个体交叉生成有效子个体。利用该算法对N-Parity问题进行了实验仿真,并对算法中评价函数各部分系数和种群规模对算法的影响进行了分析。实验证明取得了明显的优化效果,提高了神经网络的自适应能力和泛化能力,具有全局快速收敛的性能。     

An optimized RBF neural network algorithm based on partial least squares and genetic algorithm for classification of small sample

Radial basis function (RBF) neural network can use linear learning algorithm to complete the work formerly handled by nonlinear learning algorithm, and maintain the high precision of the nonlinear algorithm. However, the results of RBF would be slightly unsatisfactory when dealing with small sample which has higher feature dimension and fewer numbers. Higher feature dimension will influence the design of neural network, and fewer numbers of samples will cause network training incomplete or over-fitted, both of which restrict the recognition precision of the neural network. RBF neural network has some drawbacks, for example, it is hard to determine the numbers, center and width of the hidden layer’s neurons, which constrain the success of training. To solve the above problems, partial least squares (PLS) and genetic algorithm(GA)are introduced into RBF neural network, and better recognition precision will be obtained, because PLS is good at dealing with the small sample data, it can reduce feature dimension and make low-dimensional data more interpretative. In addition, GA can optimize the network architecture, the weights between hidden layer and output layer of the RBF neural network can ease non-complete network training, the way of hybrid coding and simultaneous evolving is adopted, and then an accurate algorithm is established. By these two consecutive optimizations, the RBF neural network classification algorithm based on PLS and GA (PLS-GA-RBF) is proposed, in order to solve some recognition problems caused by small sample. Four experiments and comparisons with other four algorithms are carried out to verify the superiority of the proposed algorithm, and the results indicate a good picture of the PLS-GA-RBF algorithm, the operating efficiency and recognition accuracy are improved substantially. The new small sample classification algorithm is worthy of further promotion.     

BP网络和多元线性回归在产量预测中的应用

采用改进的BP神经网络算法和多元线性回归模型分别建立目标函数,并以油田产量预测为例计算验证。通过比较分析,BP网络模型克服了多元线性回归模型的局限性,检验误差为0.016 2,同时表明神经网络的非线性映射能力能够更好地反应多个自变量和因变量之间的复杂关系,具有较好的精确性和可行性。     

基于遗传算法和BP网络的物体识别方法

目前常用的物体识别方法,其过程非常复杂,信息量和计算量都很大.结合遗传算法的神经网络方法,充分利用GA的全局搜索能力、BP算法的局部搜索能力和鲁棒性强的特性,提出了一种用遗传算法全局优化神经网络拓扑结构和网络权值的新编码方案进行物体识别方法.仿真结果表明,该方法既解决了BP神经网络对初始权值敏感和容易局部收敛的问题,又加快GA.BP网络的收敛速度,提高收敛精度且识别率较高,从而验证了该方法的有效性.     

A comparison of neural network and multiple regression analysis in modeling capital structure

Empirical studies of the variation in debt ratios across firms have used statistical models singularly to analyze the important determinants of capital structure. Researchers, however, rarely employ non-linear models to examine the determinants and make little effort to identify a superior prediction model. This study adopts multiple linear regressions and artificial neural networks (ANN) models with seven explanatory variables of corporation’s feature and three external macro-economic control variables to analyze the important determinants of capital structures of the high-tech and traditional industries in Taiwan, respectively. Results of this study show that the determinants of capital structure are different in both industries. The major different determinants are business-risk and growth opportunities. Based on the values of RMSE, the ANN models achieve a better fit and forecast than the regression models for debt ratio, and ANNs are cable of catching sophisticated non-linear integrating effects in both industries. It seems that the relationships between debt ratio and independent variables are not linear. Managers can apply these results for their dynamic adjustment of capital structure in achieving optimality and maximizing firm’s value.     

遗传算法优化的神经网络无速度传感器DTC系统

利用异步电动机的定子电压方程和磁链方程构造神经网络速度观测器来获得电动机的转速,观测器简单易行,通过遗传算法来优化神经网络的权值,使神经网络的权值达到最优。最后通过Matlab仿真,验证了系统设计的有效性和可行性。     

基于遗传神经网络的可信Web服务度量模型*

针对目前可信Web服务缺乏客观科学的度量方法的问题,首先建立了针对Web服务的可信属性模型TM-WS,形式化地描述Web服务的可信属性及其度量因子之间的关系;然后将神经网络的自我学习和遗传算法的全局寻优相结合,设计了可信Web服务度量模型EPTMM及其基本算法ANNGA,使其能随设定条件的变化进行灵活推算以满足可信Web服务选型中随时可能改变的用户需求;最后开发了一个简单的原型系统以验证EPTMM及ANNGA在指导可信Web服务选型中的可行性和有效性。