共查询到19条相似文献,搜索用时 250 毫秒
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基于SQP 局部搜索的混沌粒子群优化算法 总被引:1,自引:0,他引:1
提出一种基于序贯二次规划(SQP)法的混沌粒子群优化方法(CPSO-SQP).将混沌PSO作为全局搜索器,并用SQP加速局部搜索,使得粒子能够在快速局部寻优的基础上对整个空间进行搜索,既保证了算法的收敛性,又大大增加了获得全局最优的几率.仿真结果表明,算法精度高、成功率大、全局收敛速度快,明显优于现有算法.将所提出的算法用于高密度聚乙烯(HDPE)装置串级反应过程的乙烯单耗优化,根据工业反应机理以及现场操作经验分析可知,所提出的算法是可行的. 相似文献
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讨论了利用多粒子群优化算法(Multi-PSO)和径向基函数(RBF)神经网络进行缺陷参数红外识别的途径.PSO算法可以不用计算梯度,算法通用,而使用RBF神经网络作为代理模型,极大简化了复杂、费时的有限元计算,其中训练RBF神经网络的样本由有限元软件的计算结果产生.提出的多粒子群优化算法将粒子群分为若干子群,并利用粒子本身、粒子所在子群以及全局的最优解来更新粒子的速度与位置,该方法收敛速度较慢,但有可能找到问题的多个极小值.最后给出了该方法在缺陷参数红外识别中一个简单的应用例子. 相似文献
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一种改进的粒子群算法在BP网络中的应用研究 总被引:6,自引:0,他引:6
采用Sigmoid激活函数的三层前向神经网络能够以任意精度模拟复杂的非线性关系,训练算法对神经网络模式分类的性能有较大影响。基于梯度下降的BP网络存在收敛速度慢、易陷入局部极小的缺陷。粒子群算法是一种全局优化算法。本文针对粒子群算法本身存在的不足加以改进,用改进后的粒子群算法对BP网络进行训练,从而克服BP网络的一些缺陷。采用IRIS分类问题验证了本文提出的方法的有效性。实验结果表明本文采用的方法比普通PSO-BP算法效果更好。 相似文献
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在网络异常检测中,为了提高对异常状态的检测率,降低对正常状态的误判率,提出一种基于粒子群优化算法训练模糊神经网络进行网络异常检测的新方法。在对模糊神经网络训练中采取PSO算法和梯度下降算法相结合的方法,充分发挥PSO全局寻优的能力和梯度下降局部细致搜索优势。实验数据采用KDD CUP99数据集,实验结果表明,该学习算法与传统的梯度下降法(GD)相比,收敛速度快,具有更好的全局收敛性,提高了异常检测的准确性,同时该方法对于新的异常也有较高检测率。 相似文献
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神经网络能够用来检测结构损伤,但是其训练方法容易陷入局部最优。粒子群算法具有全局搜索能力,将免疫系统中的抗体抑制机理引入粒子群算法以保持粒子多样性,采用免疫粒子群算法(ImPso)训练前向神经网络。计算机仿真结果显示,训练后的网络性能优于使用一般BP算法训练的网络。 相似文献
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针对BP神经网络中采用的梯度下降法局部搜索能力强、全局搜索能力差和遗传神经网络中采用的遗传算法全局搜索能力强、局部搜索能力差的特点,提出了一种集梯度下降法和遗传算法优点为一体的混合智能学习法(Hybrid Intelligence learning algorithm),简称HI算法,并将其应用到优化多层前馈型神经网络连接权问题。对该算法进行了设计和实现,从理论和实际两方面证明混合智能学习法神经网络与BP神经网络和基于遗传算法的神经网络相比有更好的运算性能、更快的收敛速度和更高的精度。 相似文献
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This paper investigates an online gradient method with penalty for training feedforward neural networks with linear output.
A usual penalty is considered, which is a term proportional to the norm of the weights. The main contribution of this paper
is to theoretically prove the boundedness of the weights in the network training process. This boundedness is then used to
prove an almost sure convergence of the algorithm to the zero set of the gradient of the error function. 相似文献
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考虑粒子群优化算法在不确定系统的自适应控制中的应用。神经网络在不确定系统的自适应控制中起着重要作用。但传统的梯度下降法训练神经网络时收敛速度慢,容易陷入局部极小,且对网络的初始权值等参数极为敏感。为了克服这些缺点,提出了一种基于粒子群算法优化的RBF神经网络整定PID的控制策略。首先,根据粒子群算法的基本原理提出了优化得到RBF神经网络输出权、节点中心和节点基宽参数的初值的算法。其次,再利用梯度下降法对控制器参数进一步调节。将传统的神经网络控制与基于粒子群优化的神经网络控制进行了对比,结果表明,后者有更好逼近精度。以PID控制器参数整定为例,对一类非线性控制系统进行了仿真。仿真结果表明基于粒子群优化的神经网络控制具有较强的鲁棒性和自适应能力。 相似文献
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We describe an efficient method of combining the global search of genetic algorithms (GAs) with the local search of gradient descent algorithms. Each technique optimizes a mutually exclusive subset of the network's weight parameters. The GA chromosome fixes the feature detectors and their location, and a gradient descent algorithm starting from random initial values optimizes the remaining weights. Three algorithms having different methods of encoding hidden unit weights in the chromosome are applied to multilayer perceptrons (MLPs) which classify noisy digital images. The fitness function measures the MLP classification accuracy together with the confidence of the networks. 相似文献
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An improved approximation approach incorporating particle swarm optimization and a priori information into neural networks 总被引:1,自引:1,他引:0
In this paper, an improved approach incorporating adaptive particle swarm optimization (APSO) and a priori information into
feedforward neural networks for function approximation problem is proposed. It is well known that gradient-based learning
algorithms such as backpropagation algorithm have good ability of local search, whereas PSO has good ability of global search.
Therefore, in the improved approach, the APSO algorithm encoding the first-order derivative information of the approximated
function is used to train network to near global minima. Then, with the connection weights produced by APSO, the network is
trained with a modified gradient-based algorithm with magnified gradient function. The modified gradient-based algorithm can
reduce input-to-output mapping sensitivity and lessen the chance of being trapped into local minima. By combining APSO with
local search algorithm and considering a priori information, the improved approach has better approximation accuracy and convergence
rate. Finally, simulation results are given to verify the efficiency and effectiveness of the proposed approach. 相似文献
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零代价函数的前馈神经网络新算法 总被引:5,自引:0,他引:5
张代远 《计算机工程与应用》2000,36(10):79-80,96
文章提出一种全新的三层前馈神经网络算法,它比BP算法优越得多.新算法不再采用误差反向传播原理,而是选择一层自由权,通过求解线性方程组求得另一层待求权.新算法选择很广一类的隐层神经元函数,可以直接求得全局最小点,不存在BP算法的局部极小、收敛速度慢等问题.新算法较BP算法快得多. 相似文献
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This paper discusses an industrial application of a multivariable nonlinear feedforward/feedback model predictive control where the model is given by a dynamic neural network. A multi-pass packed bed reactor temperature profile is modelled via recurrent neural networks using the backpropagation through time training algorithm. This model is then used in conjunction with an optimizer to build a nonlinear model predictive controller. Results show that, compared with conventional control schemes, the neural network model based controller can achieve tighter temperature control for disturbance rejection 相似文献
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针对脉冲神经元基于精确定时的多脉冲编码信息的特点,提出了一种基于卷积计算的多层脉冲神经网络监督学习的新算法。该算法应用核函数的卷积计算将离散的脉冲序列转换为连续函数,在多层前馈脉冲神经网络结构中,使用梯度下降的方法得到基于核函数卷积表示的学习规则,并用来调整神经元连接的突触权值。在实验部分,首先验证了该算法学习脉冲序列的效果,然后应用该算法对Iris数据集进行分类。结果显示,该算法能够实现脉冲序列复杂时空模式的学习,对非线性模式分类问题具有较高的分类正确率。 相似文献
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Stefan Pittner Sagar V. Kamarthi Qinglan Gao 《Journal of Intelligent Manufacturing》1998,9(4):315-322
It is known that the force and vibration sensor signals in a turning process are sensitive to the gradually increasing flank wear. Based on this fact, this paper investigates a flank wear assessment technique in turning through force and vibration signals. Mainly to reduce the computational burden associated with the existing sensor-based methods for flank wear assessment, a so-called wavelet network is investigated. The basic idea in this new method is to optimize simultaneously the wavelet parameters (that represent signal features) and the signal-interpretation parameters (that are equivalent to neural network weights) to eliminate the feature extraction phase without increasing the computational complexity of the neural network. A neural network architecture similar to a standard one-hidden-layer feedforward neural network is used to relate sensor signal measurements to flank wear classes. A novel training algorithm for such a network is developed. The performance of this n ew method is compared with a previously developed flank wear assessment method which uses a separate feature extraction step. The proposed wavelet network can also be useful for developing signal interpretation schemes for manufacturing process monitoring, critical component monitoring, and product quality monitoring. 相似文献