基于支持向量机的烟气二氧化硫排放量预测模型

针对循环流化床锅炉控制系统的烟气SO₂对象的非线性特点,本文建立了一种基于支持向量机的烟气SO₂排放量预测模型. 由于直接网格搜索确定支持向量机回归模型参数的方法计算量大、搜索时间长,本文采用单变量参数搜索结合网格寻优的方法来确定模型参数. 仿真结果表明,基于支持向量机方法建立的循环流化床锅炉烟气SO₂排放量预测模型具有良好的预测效果.     

GA-ELM在硫铁矿制酸尾气SO2浓度预测的应用

基于对整个生产流程的管控,使硫铁矿生产硫酸尾气的SO₂浓度达标排放,提出运用GA-ELM对制酸尾气SO₂浓度进行建模预测.在硫铁矿制酸的生产过程中采集对尾气SO₂浓度影响较大的关键点参数,运用GA-ELM神经网络对烟气制酸尾气SO₂浓度进行预测.该方法在某厂实际检验,其预测结果与实际数据吻合度较高,对于调整和优化工艺指标和尾气达标排放起到很好的指导作用.     

基于改进萤火虫寻优支持向量机的PM2.5预测

针对现有PM2.5浓度预测误差较大的问题,提出一种基于改进萤火虫寻优支持向量机的预测模型（IFA-SVM）.该模型引入邻域搜索和可变步长策略改进萤火虫算法,利用改进FA对SVM的参数C、ε和γ寻优,用最优参数SVM模型预测太原市PM2.5值.其中邻域搜索策略能为参数优化提供更多更精确的候选解;可变步长可动态调整算法搜索步长,加速收敛,平衡FA的全局和局部搜索能力.将IFA-SVM预测值与萤火虫算法-支持向量机（FA-SVM）、遗传算法-支持向量机（GA-SVM）、粒子群算法-支持向量机（PSO-SVM）相比较.结果表明较其他方法,IFA-SVM模型对太原市未来一天和三天的PM2.5值都取得了更精确的预测性能.     

基于SAW气敏阵列的火电厂排放物SO2与NO2监测装置设计

针对大气污染监测的迫切需求,设计了基于SAW气敏阵列的SO₂与NO₂监测装置,并采用人工神经网络算法进行气体浓度测量。对所构建的监测装置进行了实验验证和实际测试,结果表明,装置具有良好的检测性能和自动监测优势,可推广应用到各种生产行业的大气污染监测体系中。     

Lp范数约束的多核半监督支持向量机学习方法

在机器学习领域,核方法是解决非线性模式识别问题的一种有效手段.目前,用多核学习方法代替传统的单核学习已经成为一个新的研究热点,它在处理异构、不规则和分布不平坦的样本数据情况下,表现出了更好的灵活性、可解释性以及更优异的泛化性能.结合有监督学习中的多核学习方法,提出了基于L_p范数约束的多核半监督支持向量机(semi-supervised support vector machine,简称S³VM)的优化模型.该模型的待优化参数包括高维空间的决策函数f_m和核组合权系数θm.同时,该模型继承了单核半监督支持向量机的非凸非平滑特性.采用双层优化过程来优化这两组参数,并采用改进的拟牛顿法和基于成对标签交换的局部搜索算法分别解决模型关于f_m的非平滑及非凸问题,以得到模型近似最优解.在多核框架中同时加入基本核和流形核,以充分利用数据的几何性质.实验结果验证了算法的有效性及较好的泛化性能.     

基于SVR的燃煤机组NOX含量的软测量模型

作为火电厂燃煤脱硝工作的基础,选择性催化还原(SCR)脱硝反应器入口氮氧化物(NO_X)含量的测量至关重要。针对难以准确现场实时测量NO_X含量的问题,提出了基于回归型支持向量机(SVR)的软测量模型。首先对SCR反应器生成NO_X的过程进行机理分析,并结合相关性分析、主成分分析等数据处理方法选取辅助变量,然后基于回归型支持向量机算法建立模型,最后运用BP神经网络对模型进行检验,解决了SCR反应器入口NO_X的含量的难以准确预测问题。为SCR反应器入口NO_X含量的实时、准确测量打下基础。     

基于SVM的大样本数据回归预测改进算法

针对支持向量机回归预测精度与训练样本尺寸不成正比的问题,结合支持向量机分类与回归算法,提出一种大样本数据分类回归预测改进算法。设计训练样本尺寸寻优算法,根据先验知识对样本数据进行人为分类,训练分类模型,基于支持向量机得到各类别样本的回归预测模型,并对数据进行预测。使用上证指数的数据进行实验,结果表明,支持向量机先分类再回归算法预测得到的均方误差达到12.4,低于人工神经网络预测得到的47.8,更远低于支持向量机直接回归预测得到的436.9,验证了该方法的有效性和可行性。     

支持向量机在高炉铁水温度预测中的应用

铁水温度是高炉冶炼过程的关键参数,是影响高炉稳定顺行及节能降耗的重要指标。以高炉炉内热状态的重要指示剂-铁水温度为研究对象,在综合利用K-means 聚类和支持向量机方法的各自优势和互补情况下,提出一种基于K-means 聚类的支持向量机预测铁水温度的方法,该方法首先将训练样本数据分为m 类,建立m 个支持向量机回归预测模型,同时采用粒子群算法优化模型参数; 其次建立m 个判别函数,判别待预测样本数据属于哪一类;最后将待预测样本数据代入相应类的回归模型中进行预测。相比标准支持向量机预测,得到了较高的预测精度。     

基于混合高斯模型和空间模糊度的支持向量机算法研究

在提升支持向量机分类算法精度的问题上,提出了一种基于混合高斯模型和空间模糊度的支持向量机算法。该算法通过采用多维混合高斯模型的求带分布密度概率函数的二次规划问题的最优解,减少不同的输入样本数据对分类超平面造成的影响,引入了优化后的空间模糊度因子和空间模糊度函数。在实验仿真上,采用了人工选择的样本数据集和 UCI 机器学习数据库中的样本数据集进行多次实验,最后通过对比分析的方法突出了算法在分类精度上的优势。     

基于粒子群优化的支持向量机在瓦斯浓度预测中的应用研究

为了准确预测煤矿瓦斯浓度,基于从芦岭煤矿KJ98监控系统中提取的生产现场瓦斯浓度时间序列数据,对基于粒子群优化的支持向量机理论在瓦斯浓度短期预测中的应用进行了研究。首先对瓦斯浓度时间序列进行小波软阈值去噪和相空间重构等预处理,然后采用粒子群优化算法对支持向量机的惩罚因子、损失函数、核函数参数进行了优化,并基于最优参数建立了瓦斯浓度预测的支持向量机模型。仿真结果表明,采用粒子群优化的支持向量机理论进行煤矿瓦斯浓度预测,极大地提高了预测的准确性和精确度;误差分析结果表明,该方法预测结果的误差很小,且测试样本越小,误差越小。     

Entropy based fuzzy least squares twin support vector machine for class imbalance learning

In classification problems, the data samples belonging to different classes have different number of samples. Sometimes, the imbalance in the number of samples of each class is very high and the interest is to classify the samples belonging to the minority class. Support vector machine (SVM) is one of the widely used techniques for classification problems which have been applied for solving this problem by using fuzzy based approach. In this paper, motivated by the work of Fan et al. (Knowledge-Based Systems 115: 87–99 2017), we have proposed two efficient variants of entropy based fuzzy SVM (EFSVM). By considering the fuzzy membership value for each sample, we have proposed an entropy based fuzzy least squares support vector machine (EFLSSVM-CIL) and entropy based fuzzy least squares twin support vector machine (EFLSTWSVM-CIL) for class imbalanced datasets where fuzzy membership values are assigned based on entropy values of samples. It solves a system of linear equations as compared to the quadratic programming problem (QPP) as in EFSVM. The least square versions of the entropy based SVM are faster than EFSVM and give higher generalization performance which shows its applicability and efficiency. Experiments are performed on various real world class imbalanced datasets and compared the results of proposed methods with new fuzzy twin support vector machine for pattern classification (NFTWSVM), entropy based fuzzy support vector machine (EFSVM), fuzzy twin support vector machine (FTWSVM) and twin support vector machine (TWSVM) which clearly illustrate the superiority of the proposed EFLSTWSVM-CIL.     

支持向量机应用于大气污染物时间序列预测

阐述了支持向量机应用于大气污染物时间序列预测的具体方法,建立了大气污染物时间序列的支持向量机预测模型.该方法将支持向量杌应用于大气污染物浓度预测:首先通过选择合适的信息量准则来确定模型阶数:而后通过实验的方法选择参数从而形成支持向量机的训练样本集,在此基础上建立了基于支持向量机的时间序列大气污染预测模型.实例表明,无论是在仿真过程还是在预测过程,支持向量机都具有很高的预测精度.因此.采用支持向量机方法对大气污染物时间序列进行预测分析是可行的.     

Forecasting of the daily meteorological pollution using wavelets and support vector machine

The paper presents the method of daily air pollution forecasting by using support vector machine (SVM) and wavelet decomposition. Based on the observed data of NO₂, CO, SO₂ and dust, for the past years and actual meteorological parameters, like wind, temperature, humidity and pressure, we propose the forecasting approach, applying the neural network of SVM type, working in the regression mode. To obtain the acceptable accuracy of forecast we decompose the measured time series data into wavelet representation and predict the wavelet coefficients. On the basis of these predicted values the final forecasting is prepared. The paper presents the results of numerical experiments on the basis of the measurements made by the meteorological stations, situated in the northern region of Poland.     

基于样本之间紧密度的模糊支持向量机方法

针对传统支持向量机方法中存在对噪声或野值敏感的问题,提出了一种基于紧密度的模糊支持向量机方法.在确定样本的隶属度时,不仅考虑了样本与类中心之间的关系,还考虑了类中各个样本之间的关系.通过样本之间的紧密度来描述类中各个样本之间的关系,利用包围同一类中样本的最小球半径大小来度量样本之间的紧密度.样本的隶属度依据样本在球中的位置,按照不同的规律确定与基于样本与类中心之间关系构建的模糊支持向量机方法相比,该方法有利于将野值或含噪声样本与有效样本进行区分.实验结果表明,与传统支持向量机方法及基于样本与类中心之间关系的模糊支持向量机方法相比,基于紧密度的模糊支持向量机方法具有更好的抗噪性能及分类能力.     

Functional iterative approaches for solving support vector classification problems based on generalized Huber loss

Classical support vector machine (SVM) and its twin variant twin support vector machine (TWSVM) utilize the Hinge loss that shows linear behaviour, whereas the least squares version of SVM (LSSVM) and twin least squares support vector machine (LSTSVM) uses L₂-norm of error which shows quadratic growth. The robust Huber loss function is considered as the generalization of Hinge loss and L₂-norm loss that behaves like the quadratic L₂-norm loss for closer error points and the linear Hinge loss after a specified distance. Three functional iterative approaches based on generalized Huber loss function are proposed in this paper to solve support vector classification problems of which one is based on SVM, i.e. generalized Huber support vector machine and the other two are in the spirit of TWSVM, namely generalized Huber twin support vector machine and regularization on generalized Huber twin support vector machine. The proposed approaches iteratively find the solutions and eliminate the requirements to solve any quadratic programming problem (QPP) as for SVM and TWSVM. The main advantages of the proposed approach are: firstly, utilize the robust Huber loss function for better generalization and for lesser sensitivity towards noise and outliers as compared to quadratic loss; secondly, it uses functional iterative scheme to find the solution that eliminates the need to solving QPP and also makes the proposed approaches faster. The efficacy of the proposed approach is established by performing numerical experiments on several real-world datasets and comparing the result with related methods, viz. SVM, TWSVM, LSSVM and LSTSVM. The classification results are convincing.

     

New Least Squares Support Vector Machines Based on Matrix Patterns

Support vector machine (SVM), as an effective method in classification problems, tries to find the optimal hyperplane that maximizes the margin between two classes and can be obtained by solving a constrained optimization criterion using quadratic programming (QP). This QP leads to higher computational cost. Least squares support vector machine (LS-SVM), as a variant of SVM, tries to avoid the above shortcoming and obtain an analytical solution directly from solving a set of linear equations instead of QP. Both SVM and LS-SVM operate directly on patterns represented by vector, i.e., before applying SVM or LS-SVM to a pattern, any non-vector pattern such as an image has to be first vectorized into a vector pattern by some techniques like concatenation. However, some implicit structural or local contextual information may be lost in this transformation. Moreover, as the dimension d of the weight vector in SVM or LS-SVM with the linear kernel is equal to the dimension d ₁ × d ₂ of the original input pattern, as a result, the higher the dimension of a vector pattern is, the more space is needed for storing it. In this paper, inspired by the method of feature extraction directly based on matrix patterns and the advantages of LS-SVM, we propose a new classifier design method based on matrix patterns, called MatLSSVM, such that the new method can not only directly operate on original matrix patterns, but also efficiently reduce memory for the weight vector (d) from d ₁ × d ₂ to d ₁ + d ₂. However like LS-SVM, MatLSSVM inherits LS-SVM’s existence of unclassifiable regions when extended to multi-class problems. Thus with the fuzzy version of LS-SVM, a corresponding fuzzy version of MatLSSVM (MatFLSSVM) is further proposed to remove unclassifiable regions effectively for multi-class problems. Experimental results on some benchmark datasets show that the proposed method is competitive in classification performance compared to LS-SVM, fuzzy LS-SVM (FLS-SVM), more-recent MatPCA and MatFLDA. In addition, more importantly, the idea used here has a possibility of providing a novel way of constructing learning model.     

利用粗糙集理论提高SVM预测系统的实时性

支持向量机是一种新的机器学习方法,它具有良好的推广性和分类精确性。但是在利用支持向量机的分类算法处理实际问题时,该算法的计算速度较慢、处理问题效率较低。文中介绍了一种新的学习算法,就是将粗糙集和支持向量机相结合,利用粗糙集对支持向量机的训练样本进行预处理,从而缩短样本的训练时间,提高基于SVM预测系统实时性。文中最后利用该方法进行了数据试验,试验结果表明了该方法可以大大缩短样本的训练时间,提高基于支持向量机处理预测系统的效率。从而也证明了该方法的有效性。     

基于SVR的混沌时间序列预测

支持向量机是一种基于统计学习理论的新颖的机器学习方法,由于其出色的学习性能,该技术已成为当前国际机器学习界的研究热点。这种方法已广泛用于解决分类和回归问题。论文介绍了支持向量回归算法的各种版本,同时将它们应用到混沌时间序列预测中,并且比较了它们的预测性能,为实际应用合理选择模型提供一定的依据。     

基于混合隶属度的模糊简约双支持向量机研究

双支持向量机是一种新的非平行二分类算法,其处理速度比传统支持向量机快很多,但是双支持向量机在训练之前要进行大量的复杂逆矩阵计算;在非线性情况下,它不能像传统支持向量机那样把核技巧直接运用到对偶优化问题中;并且双支持向量机没有考虑不同输入样本点会对最优分类超平面产生不同的影响。针对这些情况,提出了一种模糊简约双支持向量机。该模糊简约双支持向量机通过对二次规划函数和拉格朗日函数的改进,省略大量的逆矩阵计算,同时核技巧能直接运用到非线性分类情况下;对于混合模糊隶属度函数,不仅每个样本点到类中心的距离影响着该混合模糊隶属度,而且该样本点的邻域密度同样影响着该混合模糊隶属度。实验结果表明,与支持向量机、标准双支持向量机、双边界支持向量机、模糊双支持向量机相比,具有该混合模糊隶属度函数的简约双支持向量机不仅分类时间短,计算简单,而且分类精度高。