Time-series forecasting using a system of ordinary differential equations

This paper presents a hybrid evolutionary method for identifying a system of ordinary differential equations (ODEs) to predict the small-time scale traffic measurements data. We used the tree-structure based evolutionary algorithm to evolve the architecture and a particle swarm optimization (PSO) algorithm to fine tune the parameters of the additive tree models for the system of ordinary differential equations. We also illustrate some experimental comparisons with genetic programming, gene expression programming and a feedforward neural network optimized using PSO algorithm. Experimental results reveal that the proposed method is feasible and efficient for forecasting the small-scale traffic measurements data.     

模拟退火PSO的神经网络的网络流量预测模型

为解决网络流量时间序列的预测问题,针对传统BP神经网络的网络流量时间序列预测模型容易陷入局部极小值的不足,提出一种基于模拟退火的微粒群算法训练神经网络的网络流量时间序列预测模型.将模拟退火算法和基本粒子微粒群算法相结合,设计出一种基于模拟退火的微粒群算法.利用基于模拟退火微粒群算法优化BP神经网络的权值和阀值,对实际采集的网络流量时间序列进行建模.实验结果表明,基于模拟退火的微粒群算法训练的神经网络具有较高的预测效果,相对于传统的神经网络模型具有更高的预测精度和良好的自适应性.     

A parallel evolving algorithm for flexible neural tree

In the past few decades, much success has been achieved in the use of artificial neural networks for classification, recognition, approximation and control. Flexible neural tree (FNT) is a special kind of artificial neural network with flexible tree structures. The most distinctive feature of FNT is its flexible tree structures. This makes it possible for FNT to obtain near-optimal network structures using tree structure optimization algorithms. But the modeling efficiency of FNT is always a problem due to its two-stage optimization. This paper designed a parallel evolving algorithm for FNT (PE-FNT). This algorithm uses PIPE algorithm to optimize tree structures and PSO algorithm to optimize parameters. The evaluation processes of tree structure populations and parameter populations were both parallelized. As an implementation of PE-FNT algorithm, two parallel programs were developed using MPI. A small data set, two medium data sets and three large data sets were applied for the performance evaluations of these programs. Experimental results show that PE-FNT algorithm is an effective parallel FNT algorithm especially for large data sets.     

基于改进的QPSO训练BP网络的网络流量预测*

为了提高网络流量预测的精度,采用一种改进的QPSO算法训练BP神经网络对网络流量数据的时间序列进行建模预测。针对标准的QPSO算法不可避免地出现早熟的不足,提出一种新的基于参数自适应的QPSO算法,较好地避免了粒子群的早熟,提高了算法的全局收敛性能。仿真实验结果表明,与PSO训练的BP网络、QPSO训练的BP网络作为预测模型相比,该模型具有更高的预测精度及很好的稳定性。     

Optimization of self-organizing polynomial neural networks

The main disadvantage of self-organizing polynomial neural networks (SOPNN) automatically structured and trained by the group method of data handling (GMDH) algorithm is a partial optimization of model weights as the GMDH algorithm optimizes only the weights of the topmost (output) node. In order to estimate to what extent the approximation accuracy of the obtained model can be improved the particle swarm optimization (PSO) has been used for the optimization of weights of all node-polynomials. Since the PSO is generally computationally expensive and time consuming a more efficient Levenberg–Marquardt (LM) algorithm is adapted for the optimization of the SOPNN. After it has been optimized by the LM algorithm the SOPNN outperformed the corresponding models based on artificial neural networks (ANN) and support vector method (SVM). The research is based on the meta-modeling of the thermodynamic effects in fluid flow measurements with time-constraints. The outstanding characteristics of the optimized SOPNN models are also demonstrated in learning the recurrence relations of multiple superimposed oscillations (MSO).     

基于蚁群粒子群的模糊神经网络交通流量预测

实时准确的交通流量预测是智能交通诱导和交通控制实现的前提和关键。针对城市交通流的特点,建立了模糊神经网络预测模型,并将全局优化的蚁群算法和粒子群算法组成递阶结构优化模糊神经网络的参数。算法中,主级为蚁群算法,进行全局搜索;从级为粒子群算法,进行局部搜索。仿真结果表明该模型能够取得比梯度下降法更高的预测精度。     

基于PSO-SVM的短期交通流预测方法

准确的交通流量预测是智能交通系统中的关键问题。在分析支持向量机SVM回归估计方法参数性能的基础上,提出了粒子群算法PSO优化参数的PSO-SVM短期交通流预测模型。模型利用支持向量机具有结构风险最小化的特性和粒子群算法快速全局优化特点,实现了数据降维并且保持了交通流序列的特征,因此可以高效地预测交通流量。用G107国道现场采集的数据仿真表明了该模型的有效性,预测平均误差为3.4%。     

改进PSO优化神经网络的短时交通流预测

在短时交通流预测中,传统PSO优化神经网络预测模型对逃逸粒子直接取边界值且自身无相应的变异机制,这对于维持粒子群多样性、寻找最优解是不利的。为更进一步提高短时交通流预测精度,将在传统PSO优化BP神经网络的基础上,引入边界变异算子、自变异算子对粒子进行双重变异以优化网络配置参数。用实测的北京二环交通流数据对改进的预测模型进行验证,结果表明该模型更有利于搜寻全局最优解,且寻优时间更短,能有效改善短时交通流预测性能。     

Hybrid flexible neural‐tree‐based intrusion detection systems

An intrusion is defined as a violation of the security policy of the system, and, hence, intrusion detection mainly refers to the mechanisms that are developed to detect violations of system security policy. Current intrusion detection systems (IDS) examine all data features to detect intrusion or misuse patterns. Some of the features may be redundant or contribute little (if anything) to the detection process. The purpose of this study is to identify important input features in building an IDS that is computationally efficient and effective. This article proposes an IDS model based on a general and enhanced flexible neural tree (FNT). Based on the predefined instruction/operator sets, a flexible neural tree model can be created and evolved. This framework allows input variables selection, overlayer connections, and different activation functions for the various nodes involved. The FNT structure is developed using an evolutionary algorithm, and the parameters are optimized by a particle swarm optimization algorithm. Empirical results indicate that the proposed method is efficient. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 337–352, 2007.     

Prediction interval of wind power using parameter optimized Beta distribution based LSTM model

Prediction interval of wind power (PIWP) is crucial to assessing the economic and safe operation of the wind turbine and providing support for analysis of the stability of power systems. The hybrid model (Beta-PSO-LSTM) of long short-term memory (LSTM) neural network and Beta distribution function based particle swarm optimization (PSO) is put forward for prediction interval of wind power. In order to enhance the performance of the Beta-PSO-LSTM for PIWP in training process, wind power series are divided into different power intervals, and then the Beta-PSO-LSTM is used to estimate each power interval of the original wind power series. Furthermore, based on the analysis of the interval forecasting error information in wind power training data set, Beta distribution model is proposed to get better PIWP, and PSO is used to optimize the parameters of the model. Finally, the proposed Beta-PSO-LSTM model is compared with the Beta distribution optimized by PSO based the BP neural network (Beta-PSO-BP), the normal distribution based LSTM neural network (Norm-LSTM), Beta distribution based LSTM neural network (Beta-LSTM), and Beta distribution optimized by iterative method based LSTM neural network (Beta-IM-LSTM) for PIWP. The simulation results show that the PIWP obtained by the Beta-PSO-LSTM model has higher reliability and narrower interval bandwidth, which can provide decision support for the safe and stable operation of power systems.     

混合粒子群优化算法优化前向神经网络结构和参数

提出了综合利用粒子群优化算法（PSO）和离散粒子群优化算法（D-PSO）同时优化前向神经网络结构和参数的新方法。该算法使用离散粒子群优化算法优化神经网络连接结构,用多维空间中0或1取值的粒子来描述所有可能的神经网络连接,同时使用粒子群优化算法优化神经网络权值。将经过该算法训练的神经网络应用于故障诊断,能够有效消除冗余连接结构对网络诊断能力的影响。仿真试验的结果表明,相比遗传算法等其他算法,该算法能够有效改善神经网络结构和参数的优化效率,提高故障模式识别的准确率。     

基于改进PSO优化SVR的交通事故预测模型

为了有效预测交通事故,提出一种基于改进粒子群算法优化支持向量回归机的预测模型。改进粒子群算法利用网格搜索对全局最优粒子的邻域进行精细搜索,结合粒子群算法较快的收敛速度和网格搜索较强局部搜索能力的优点,提高了支持向量回归机相关参数的优化精度,进而改善了交通事故预测模型的预测性能。仿真结果表明,基于改进粒子群算法优化支持向量回归机的交通事故预测模型达到了较快的学习速度和较高的预测精度,具有良好的工程应用性。      

一种井下配电网故障测距方法

针对采用随机选取法、K-均值聚类法确定RBF神经网络隐含层节点中心和宽度只能得到局部最优解、基本粒子群优化算法易发生早熟收敛且对于某些函数优化精度差的问题,提出了将惯性权重模型和收敛因子模型相结合的改进的粒子群优化算法;针对煤矿井下配电网发生单相接地故障后定位困难、传统的故障测距方法存在可靠性差、测距精度低的问题,提出了采用改进的粒子群优化算法优化RBF神经网络进行井下配电网单相接地故障测距的方法。仿真结果表明,经改进的粒子群优化算法优化的RBF神经网络的测距精度高于RBF神经网络,能够实现故障点的准确、可靠定位。     

基于PSO与LS-SVM的作物需水量预测

为了提高作物需水量预测精度,提出基于粒子群优化算法(PSO)优化最小二乘支持向量机(LS-SVM)的预测模型。该模型以空气湿度、温度、太阳辐射以及风速为输入,利用多项式核函数和径向基核函数的非负线性组合构造核函数,将粒子群优化算法(PSO)与交叉验证方法用于确定模型参数。实验结果表明与神经网络和随机森林相比,PSO优化的LS-SVM可获得更好的预测精度和泛化能力,可用于节水灌溉,具有较高的应用价值。     

粒子群可拓的新冠肺炎建模与仿真

本文提出了一种基于粒子群可拓神经网络预测模型.根据国外近段时间每日新增新冠肺炎确诊人数,利用可拓神经网络模型对国外日新增新冠肺炎确诊人数进行预测,并利用粒子群算法(PSO)对权值进行优化,最后与LSSVM、ABC-LSSVM及PSO-LSSVM模型进行比较.结果表明:采用文中提出的粒子群可拓神经网络模型拟合效果较好,精...     

基于PSO-BP神经网络的网络流量预测与研究

传统网络流量预测采用线性方法进行处理,不能很好地满足要求.根据互联网通信量的自相似性,提出一种基于BP网络的粒子群优化PSO-BP算法进行网络流量预测,用PSO算法对BP网络节点的初始权值进行优化,并利用历史记录训练BP网络,采用Matlab进行仿真.试验结果表明,PSO-BP算法加快了BP网络收敛速度,训练结果的均方误差函数mse在5%以内,提高了网络流量预测精度.     

基于柔性神经树和表面肌电信号的手势识别模型

表面肌电信号因为具有非入侵式、易于采集特点,被广泛应用于康复医疗和行为识别等领域.传统的基于表面肌电信号sEMG( Surface Electromyography)的手势识别通常采用数字信号处理DSP( Digital Signal Processing)芯片或者集合方法研究实时识别问题.这些方法易导致数学模型参数繁多、硬件连接复杂和实时识别率较低.提出一种基于肌电信号与柔性神经树FNT(Flexible Neural Trees)模型的实时手势识别模型.柔性神经树模型通过简单的预定义建立,能够解决人工神经网络ANN( Artificial Neural Network)的结构高依赖性问题.柔性神经树模型不仅能够避免复杂的计算和电路连接,还具有较高的实时识别率.针对六名参与者的六种手势进行实验,实验结果表明:该模型的均方根误差RMSE(Root Mean Square Error)最低为0.000385,实时识别率最高可达97.53％.     

一种计算话务量的进化神经网络方法

话务量是度量用户使用电话设备频繁程度的一个重要参量,由于目前话务分布呈现出显著的立体性、多业务性和非泊松流等特点,不能直接应用欧兰Ｂ公式进行计算。为此,从计算智能出发提出一种基于PSO算法的进化神经计算方法,主要包括话务量及其相关参量的获取、神经网络结构的优化、基于PSO算法的网络训练,以及话务量计算等步骤。通过对河北省某市小灵通业务的详细研究,利用近半年来的话务量与无线阻塞率、来话接通率和掉话率等参量构成的样本信息进行建模,所计算的话务量精度高,表明其方法切实可行且效果显著。     

基于PSO-BP神经网络的湿度传感器温度补偿

针对自动气象站采用的HMP45D型温湿一体化传感器在实际应用过程中易受温度影响的问题,提出了基于粒子群优化算法(PSO)的BP神经网络温度补偿模型,利用粒子群优化算法对BP神经网络的初始权值阈值进行全局寻优,将粒子群优化算法优化好的权值阈值赋给BP神经网络,对BP神经网络进行训练。根据不同温度条件下测得的多组湿度传感器数据,通过建立模型,实现温度补偿,与传统BP神经网络补偿结果进行比较。实验表明,与传统BP神经网络模型相比,利用PSO-BP神经网络模型进行温度补偿后所得的误差绝对值之和降低了10.3887%RH,PSO-BP神经网络可以克服传统BP神经网络易陷入局部极值的局限,补偿精度更高,能更加有效地补偿温度对湿度传感器的影响。     

粒子群算法优化BP神经网络的粉尘浓度预测

对综采工作面粉尘浓度预测的方法是建立BP神经网络预测模型.为了提高算法的拟合能力及预测的准确度,使用粒子群算法对目标函数进行改进,即将粒子群算法寻到的最优权值和阈值应用于神经网络预测模型求综采工作面粉尘浓度.比较分析新的预测模型与常用的灰色模型以及标准的BP神经网络算法,结果表明粒子群优化的神经网络算法的拟合能力和预测的准确率显著提高.