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1.
针对污水处理中某些生物参数难以在线测量的情况,本文提出了一种基于小波核的多尺度最小二乘小波支持向量机软测量建模方法:。首先,选取墨西哥草帽小波函数作为最小二乘支持向量机的核函数,进而设计出多尺度小波最小二乘支持向量回归机(MW-LSSVR)。然后利用该支持向量机和出水水质参数特性建立混合软测量模型,实现对出水BOD浓度、COD浓度在线预测。通过在实际污水处理过程的应用,结果:表明本建模方法:具有较高的预测精度和较快的模型学习速度,能对BOD的做出准确的预测,一定程度上可以替代某些昂贵的在线测量仪表,给污水处理厂工作人员提供了控制操作依据,具有一定的实际应用价值。  相似文献   

2.
针对污水处理过程中化学需氧量(chemical oxygen demand, COD)难以在线测量的问题,提出了一种基于径向基函数(radial basis function, RBF)神经网络的软测量模型.首先,用污水处理厂实测数据挑选出与COD相关的过程变量作为输入变量;其次,基于RBF神经网络建立出水COD软测量模型,利用自适应遗传算法改进的麻雀搜索算法(adaptive genetic algorithm improved sparrow search algorithm, AGAISSA)优化RBF神经网络的中心值、宽度值以及权值,通过改进麻雀位置更新公式以及引入遗传算法中的自适应交叉和变异操作保证了软测量模型的精度;最后,将RBF神经网络的软测量模型应用于污水处理厂实测数据加以验证,结果表明:AGAISSA优化RBF神经网络模型能够对出水COD进行准确的预测,具有较高的预测精度.  相似文献   

3.
基于支持向量机的软测量技术及其应用   总被引:3,自引:0,他引:3  
支持向量机(SVM)是一种基于结构风险最小化原理,具有很好推广性能的学习算法。讨论了基于最小二乘支持向量机(LS-SVM)的软测量数据建模原理和方法,并将其应用在汽车排放的氮氧化合物NOX软测量中。通过与基于神经网络的软测量方法进行比较,结果显示出SVM的明显的优势,特别是对小样本、非线性、高维数一类软测量问题的建模,提供了一种有效的途径。  相似文献   

4.
污水处理系统是一个包含海量信息的非线性复杂系统。针对污水处理出水水质BOD(生物化学需氧量)、COD(化学需氧量)、TN(总含氮量)等难以在线实时检测等问题,建立了基于在线MIMO-LSSVM(多输入多输出最小二乘支持向量机)和PSO(微粒子群算法)的污水处理软测量模型。仿真结果表明,建立的软测量模型精度高、速度快,能很好地实现污水处理出水指标COD、BOD、TN等参数的实时测量和估计,为污水处理的实时在线控制创造必要的前提条件。  相似文献   

5.
以某污水处理厂为背景,针对污水处理系统受环境影响大、运行环境恶劣等特点,设计了一套基于InTouch-v9.5、PLC的污水处理控制系统,实现整个污水处理控制系统的信息化和自动化。针对BOD浓度、COD浓度难于在线测量、测量成本高昂的缺点,提出利用支持向量回归机与参数特性混合建模,实现对BOD浓度与COD浓度的在线软测量,有效解决上述问题。该设计已经应用到实际生产中,运行效果良好。  相似文献   

6.
基于支持向量机的污水处理软测量算法的研究   总被引:2,自引:0,他引:2  
针对污水处理过程中生化需氧量BOD难以实时在线测量的问题,建立了用于预估BOD的支持向量机(SVM)的软测量模型。考虑到该支持向量机模型的测量精度取决于其两个参数C、σ能否获得最优值,采用遗传算法和粒子群优化算法,实现对这两个参数的寻优。仿真结果表明:该软测量模型的测量精度较高,可用于污水处理厂对BOD进行在线测量。  相似文献   

7.
针对污水处理过程中水质参数COD指标难以在线检测的问题,提出一种基于分布式改进BP神经网络和灰色预测的COD指标集成软测量模型。为反映污水处理过程的不同工况,采用满意聚类算法对数据样本进行聚类处理,将数据样本划分为若干个子样本集,利用改进BP神经网络方法分别为每个子样本集建立预测模型,计算当前输入数据与各个聚类中心的欧式距离,将欧式距离较小的部分预测模型的输出进行综合,得到分布式神经网络的COD指标预估值;为反映COD指标的时间相关性,基于COD指标历史数据采用改进灰色预测建模方法计算得到当前时刻COD指标的预估值;采用动态加权方法将获得两个COD指标预估值进行加权集成。仿真实验表明,集成软测量模型具有较好的预测性能,可以满足污水处理过程COD指标实时检测的精度要求。  相似文献   

8.
针对最小二乘支持向量机(LS-SVM)在建立醋酸乙烯(VAC)聚合率软测量模型过程中最优模型参数的选择问题,提出了利用一种量子遗传算法来自动选取LS-SVM模型正则化参数和核函数参数的方法;把LS-SVM模型参数的选择问题转化为优化问题,利用全局搜索能力强的量子遗传算法优化LS-SVM建模过程的重要参数,建立了基于QGA-LSSVM方法的VAC聚合率软测量模型;仿真结果表明:与已有的神经网络和支持向量机软测量方法相比,该模型泛化能力强,精度高,更有利于醋酸乙烯聚合率测量工程实际运用。  相似文献   

9.
一种聚类加权支持向量机算法及其在软测量中的应用   总被引:1,自引:1,他引:0  
针对支持向量机应用于软测量建模时,工业过程数据中特异点影响建模精度的问题,提出聚类加权支持向量机方法.该方法首先对建模数据进行聚类分析,根据聚类结果,对各类数据的惩罚系数进行相应的加权,改变权值大小既能减小特异点对模型的影响程度,又能将其包含的生产过程信息引入到软测量模型中.聚丙烯熔融指数软测量的实例研究表明,通过对建模数据进行聚类分析和加权处理,聚类加权支持向量机比标准支持向量机建模更准确.  相似文献   

10.
基于SVM的软测量建模   总被引:30,自引:2,他引:30  
支持向量机(Support Vector Machines)是一种基于统计学习理论的新型学习机,本 文提出用支持向量机建立软测量模型.理论分析和仿真研究表明,该方法学习速度快、跟踪 性能好、泛化能力强、对样本的依赖程度低,比基于RBF神经网络的软测量建模具有更好的 推广能力.  相似文献   

11.
水质预测是水环境污染防治的重要内容,针对传统水质预测方法精度低、收敛速度慢等问题,研究首先选取Symlets和Daubechies小波系作为小波函数,对原始数据进行去噪处理并对比,再结合RBF、Elman神经网络以及支持向量机各自优点,通过不同算法优化三种预测模型,提出基于Adaboost算法将优化后的RBF、Elman神经网络以及支持向量机相结合的组合预测方法。以北海为对象进行仿真实验,验证基于Adaboost的溶解氧组合预测方法的有效性,并分别与单一模型的预测结果进行对比,结果表明该方法相比于传统的单一模型预测精度得到了提高,为水质精准预测提供了一种新思路。  相似文献   

12.
In this paper, a one-layer recurrent neural network with a discontinuous hard-limiting activation function is proposed for quadratic programming. This neural network is capable of solving a large class of quadratic programming problems. The state variables of the neural network are proven to be globally stable and the output variables are proven to be convergent to optimal solutions as long as the objective function is strictly convex on a set defined by the equality constraints. In addition, a sequential quadratic programming approach based on the proposed recurrent neural network is developed for general nonlinear programming. Simulation results on numerical examples and support vector machine (SVM) learning show the effectiveness and performance of the neural network.  相似文献   

13.
An unsupervised competitive neural network for efficient clustering of Gaussian probability density function (GPDF) data of continuous density hidden Markov models (CDHMMs) is proposed in this paper. The proposed unsupervised competitive neural network, called the divergence-based centroid neural network (DCNN), employs the divergence measure as its distance measure and utilizes the statistical characteristics of observation densities in the HMM for speech recognition problems. While the conventional clustering algorithms used for the vector quantization (VQ) codebook design utilize only the mean values of the observation densities in the HMM, the proposed DCNN utilizes both the mean and the covariance values. When compared with other conventional unsupervised neural networks, the DCNN successfully allocates more code vectors to the regions where GPDF data are densely distributed while it allocates fewer code vectors to the regions where GPDF data are sparsely distributed. When applied to Korean monophone recognition problems as a tool to reduce the size of the codebook, the DCNN reduced the number of GPDFs used for code vectors by 65.3% while preserving recognition accuracy. Experimental results with a divergence-based k-means algorithm and a divergence-based self-organizing map algorithm are also presented in this paper for a performance comparison.  相似文献   

14.
In this article, an iterative procedure is proposed for the training process of the probabilistic neural network (PNN). In each stage of this procedure, the Q(0)-learning algorithm is utilized for the adaptation of PNN smoothing parameter (σ). Four classes of PNN models are regarded in this study. In the case of the first, simplest model, the smoothing parameter takes the form of a scalar; for the second model, σ is a vector whose elements are computed with respect to the class index; the third considered model has the smoothing parameter vector for which all components are determined depending on each input attribute; finally, the last and the most complex of the analyzed networks, uses the matrix of smoothing parameters where each element is dependent on both class and input feature index. The main idea of the presented approach is based on the appropriate update of the smoothing parameter values according to the Q(0)-learning algorithm. The proposed procedure is verified on six repository data sets. The prediction ability of the algorithm is assessed by computing the test accuracy on 10 %, 20 %, 30 %, and 40 % of examples drawn randomly from each input data set. The results are compared with the test accuracy obtained by PNN trained using the conjugate gradient procedure, support vector machine algorithm, gene expression programming classifier, k–Means method, multilayer perceptron, radial basis function neural network and learning vector quantization neural network. It is shown that the presented procedure can be applied to the automatic adaptation of the smoothing parameter of each of the considered PNN models and that this is an alternative training method. PNN trained by the Q(0)-learning based approach constitutes a classifier which can be treated as one of the top models in data classification problems.  相似文献   

15.
This paper presents a new version of fuzzy support vector machine (FSVM) developed for product design time estimation. As there exist problems of finite samples and uncertain data in the estimation, the input and output variables are described as fuzzy numbers, with the metric on fuzzy number space defined. Then, the fuzzy nu-support vector machine (Fnu-SVM) is proposed on the basis of combining the fuzzy theory with the nu-support vector machine, followed by the presentation of a time estimation method based on Fnu-SVM and its relevant parameter-choosing algorithm. The results from the applications in injection mold design and software product design confirm the feasibility and validity of the estimation method. Compared with the fuzzy neural network (FNN) model, our Fnu-SVM method requires fewer samples and enjoys higher estimating precision  相似文献   

16.
A one-layer recurrent neural network for support vector machine learning.   总被引:1,自引:0,他引:1  
This paper presents a one-layer recurrent neural network for support vector machine (SVM) learning in pattern classification and regression. The SVM learning problem is first converted into an equivalent formulation, and then a one-layer recurrent neural network for SVM learning is proposed. The proposed neural network is guaranteed to obtain the optimal solution of support vector classification and regression. Compared with the existing two-layer neural network for the SVM classification, the proposed neural network has a low complexity for implementation. Moreover, the proposed neural network can converge exponentially to the optimal solution of SVM learning. The rate of the exponential convergence can be made arbitrarily high by simply turning up a scaling parameter. Simulation examples based on benchmark problems are discussed to show the good performance of the proposed neural network for SVM learning.  相似文献   

17.
Support vector machine (SVM) is a powerful algorithm for classification and regression problems and is widely applied to real-world applications. However, its high computational load in the test phase makes it difficult to use in practice. In this paper, we propose hybrid neural network (HNN), a method to accelerate an SVM in the test phase by approximating the SVM. The proposed method approximates the SVM using an artificial neural network (ANN). The resulting regression function of the ANN replaces the decision function or the regression function of the SVM. Since the prediction of the ANN requires significantly less computation than that of the SVM, the proposed method yields faster test speed. The proposed method is evaluated by experiments on real-world benchmark datasets. Experimental results show that the proposed method successfully accelerates SVM in the test phase with little or no prediction loss.  相似文献   

18.
对灰色、神经网络和支持向量机的三个预测模型进行研究,以某某类科技图书1993-2000年的年发行量为例,对科技图书市场进行预测,经过比较,支持向量机的预测方法精度较高。本方法可推广应用于其他类图书市场的预测。  相似文献   

19.
Fuzzy neural network (FNN) has long been recognized as an efficient and powerful learning machine for general machine learning problems. Recently, Wilcoxon fuzzy neural network (WFNN), which generalizes the rank-based Wilcoxon approach for linear parametric regression problems to nonparametric neural network, was proposed aiming at improving robustness against outliers. FNN and WFNN are nonparametric models in the sense that they put no restrictions, except possibly smoothness, on the functional form of the regression function. However, they may be difficult to interpret and, even worse, yield poor estimates with high computational cost when the number of predictor variables is large. To overcome this drawback, semiparametric models have been proposed in statistical regression theory. A semiparametric model keeps the easy interpretability of its parametric part and retains the flexibility of its nonparametric part. Based on this, semiparametric FNN and semiparametric WFNN will be proposed in this paper. The learning rules are based on the backfitting procedure frequently used in semiparametric regression. Simulation results show that the semiparametric models perform better than their nonparametric counterparts.  相似文献   

20.
In this study, a modified hybrid neural network with asymmetric basis functions is presented for feature extraction of spike and slow wave complexes in electroencephalography (EEG). Feature extraction process has a great importance in all pattern recognition and classification problems. A gradient descent algorithm, indeed a back propagation type, is adapted to the proposed artificial neural network. The performance of the proposed network is measured using a support vector machine classifier fed by features extracted using the proposed neural network. The results show that the proposed neural network model can effectively be used in pattern recognition tasks. In experiments, real EEG data are used.  相似文献   

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