ELM-based gene expression classification with misclassification cost

Cost-sensitive learning is a crucial problem in machine learning research. Traditional classification problem assumes that the misclassification for each category has the same cost, and the target of learning algorithm is to minimize the expected error rate. In cost-sensitive learning, costs of misclassification for samples of different categories are not the same; the target of algorithm is to minimize the sum of misclassification cost. Cost-sensitive learning can meet the actual demand of real-life classification problems, such as medical diagnosis, financial projections, and so on. Due to fast learning speed and perfect performance, extreme learning machine (ELM) has become one of the best classification algorithms, while voting based on extreme learning machine (V-ELM) makes classification results more accurate and stable. However, V-ELM and some other versions of ELM are all based on the assumption that all misclassifications have same cost. Therefore, they cannot solve cost-sensitive problems well. To overcome the drawback of ELMs mentioned above, an algorithm called cost-sensitive ELM (CS-ELM) is proposed by introducing misclassification cost of each sample into V-ELM. Experimental results on gene expression data show that CS-ELM is effective in reducing misclassification cost.     

基于EMD-GAELM-ARIMA算法的大坝变形预测

In view of the fact that it is difficult for statistical models to make good predictions of nonlinear and non-stationary dam deformation, artificial intelligence algorithms are induced. The empirical mode decomposition method (EMD), genetic algorithm (GA) optimized extreme learning machine (ELM), and ARIMA error correction model were used to construct a dam deformation prediction model. First this paper uses EMD to decompose and reconstruct the monitoring data to stabilize it and obtain eigenmode functions and residual sequences with physical significance; then uses GAELM to analyze and predict the decomposition results; finally, uses ARIMA model to correct errors. Taking a concrete rockfill dam as an example, the dam deformation prediction model constructed by the optimization algorithm is used to analyze and predict it. The analysis results show that the EMD-GAELM-ARIMA model algorithm has higher prediction accuracy than the traditional single algorithm. It is feasible in dam deformation prediction.     

极限学习机的分类器集成模型研究

将极限学习机算法与旋转森林算法相结合,提出了以ELM算法为基分类器并以旋转森林算法为框架的RF-ELM集成学习模型。在8个数据集上进行了3组预测实验,根据实验结果讨论了ELM算法中隐含层神经元个数对预测结果的影响以及单个ELM模型预测结果不稳定的缺陷;将RF-ELM模型与单ELM模型和基于Bagging算法集成的ELM模型相比较,由稳定性和预测精度的两组对比实验的实验结果表明,对ELM的集成学习可以有效地提高ELM模型的性能,且RF-ELM模型较其他两个模型具有更好的稳定性和更高的准确率,验证了RF-ELM是一种有效的ELM集成学习模型。     

改进小波阈值法与极限学习机在MEMS陀螺误差补偿中的应用

MEMS陀螺随机误差是影响其精度的主要因素之一。针对MEMS陀螺随机误差的问题,提出一种基于改进的阈值函数的小波去噪结合极限学习机算法建模的补偿方法。通过改进小波阈值法提高去噪效果,然后由极限学习机构建MEMS陀螺误差补偿模型。通过实例研究,结果显示该方法能良好地补偿随机误差,与其他方法比较,具有更好的效果。     

基于Xgboost优化的KELM滑坡预报模型研究

针对极限学习机对滑坡预测准确性低及在训练过程中模型不稳定的问题,引入RBF高斯核函数并使用极限梯度提升树算法Xgboost对KELM进行优化,建立了Xgboost优化后的Xgboost-KELM预测模型;首先采用高斯核RBF作为极限学习机的核函数,解决隐藏节点随机映射问题,增加模型稳定性及适用性;其次将清洗后的监测数据作为模型输入,并使用Xgboost寻优算法对核函数中的超参数进行优化,通过4组测试集进行Xgboost-KELM建模,依据均方误差迭代曲线得出最佳超参数;最后使用两组10%样本集验证模型评价指标及稳定性,实验结果AUC均值对比模型至少提高3个百分点,Precision、Accuracy及Recall至少高于对比模型1.7个百分点,同时Xgboost-KELM模型的方差及偏差都较小,证明该模型稳定性较好,实验结果说明Xgboost-KELM模型具有较好的预测效果,在滑坡灾害预测中有较好的预测能力。     

极限学习机在机场旅客吞吐量预测中的应用

极限学习机(ELM)是一种新型单馈层神经网络算法,在训练过程中只需要设置合适的隐藏层节点个数,随机赋值输入权值和隐藏层偏差,一次完成无需迭代.结合遗传算法在预测模型参数寻优方面的优势,找到极限学习机的最优参数取值,建立成都双流国际机场旅客吞吐量预测模型,通过对比支持向量机、BP神经网络,分析遗传-极限学习机算法在旅客吞吐量预测中的可行性和优势.仿真结果表明遗传-极限学习机算法不仅可行,并且与原始极限学习机算法相比,在预测精度和训练速度上具有比较明显的优势.     

The extreme learning machine learning algorithm with tunable activation function

In this paper, we propose an extreme learning machine (ELM) with tunable activation function (TAF-ELM) learning algorithm, which determines its activation functions dynamically by means of the differential evolution algorithm based on the input data. The main objective is to overcome the problem dependence of fixed slop of the activation function in ELM. We mainly considered the issue of processing of benchmark problems on function approximation and pattern classification. Compared with ELM and E-ELM learning algorithms with the same network size or compact network configuration, the proposed algorithm has improved generalization performance with good accuracy. In addition, the proposed algorithm also has very good performance in the TAF neural networks learning algorithms.     

基于小波KPCA与IQGA-ELM的煤与瓦斯突出预测研究

为有效预防煤与瓦斯突出灾害,针对煤与瓦斯突出预测精度和效率不高问题,提出基于小波核主成分分析(KPCA)和改进的极限学习机(IQGA-ELM)的煤与瓦斯突出预测方法.通过小波核主成分分析法对原始致突指标进行非线性降维处理,提取出致突指标主成分序列,将其作为极限学习机(ELM)网络神经的输入,利用改进量子遗传算法(IQGA)对ELM的输入层权值和隐含层阈值进行优化,建立小波KPCA-IQGA-ELM预测模型,模型的输出为煤与瓦斯突出强度的预测结果.研究结果表明,该模型泛化能力强,可以对煤与瓦斯突出强度进行有效预测.     

一种基于超限学习机的电子磁罗盘非线性误差补偿方法

针对磁罗盘传感器非线性校正中现有方法的不足,提出采用小波函数和双曲正弦函数作为超限学习机(ELM)的激活函数,并将此改进超限学习机用于磁罗盘的校正.同时,阐述了传感器的非线性校正原理,磁罗盘航向误差模型及改进超限学习机的实现过程,并分别采用BP神经网络法和传统ELM对磁罗盘进行非线性校正.实验结果表明,改进ELM算法补偿后最大误差为0.103°,均方根误差为0.0596°,优于BP神经网络算法(补偿后最大误差为0.5°,均方根误差为0.1805°)和传统ELM神经网络(补偿后最大误差为0.21°,均方根误差为0.1056°).     

工业机器人定位误差规律分析及基于ELM算法的精度补偿研究

针对工业机器人应用于飞机零部件自动化钻孔时绝对定位精度较差的问题,提出利用极限学习机（ELM）算法建立机器人法兰中心点理论位置与实际位置之间的误差模型,并优化补偿机器人定位精度的方法．首先基于空间网格采样方法,获得了机器人绝对定位误差沿机器人基坐标系不同方向的误差变化规律,分析了建模补偿的可行性;其次建立基于ELM算法的误差补偿模型,并针对误差模型训练中隐含层神经元个数取值问题进行了分析优化．实验结果表明,机器人绝对定位误差值沿其坐标系不同方向存在不同的变化规律,补偿前绝对定位误差分布范围为0.29 mm~0.58 mm,平均误差为0.41 mm;补偿后定位误差分布范围降低到0.04 mm~0.32 mm,平均误差为0.18 mm;采用ELM算法建模的补偿速度快,泛化性能好．     

基于改进KH算法优化ELM的目标威胁估计

为了提高目标威胁度估计的精确度,建立了反向学习磷虾群算法（OKH）优化极限学习机的目标威胁估计模型（OKH-ELM）,提出基于此模型的算法。该模型使用反向学习策略优化磷虾群算法,并通过改进后的磷虾群算法优化极限学习机初始输入权重和偏置,使优化后的极限学习机能够对威胁度测试样本集做更好的预测。实验结果显示,OKH算法能够更好地优化极限学习机的权值与阈值,使建立的极限学习机目标威胁估计模型具有更高的预测精度和更强的泛化能力,能够精准、有效地实现目标威胁估计。     

An integrated chaotic time series prediction model based on efficient extreme learning machine and differential evolution

In this paper, an integrated model based on efficient extreme learning machine (EELM) and differential evolution (DE) is proposed to predict chaotic time series. In the proposed model, a novel learning algorithm called EELM is presented and used to model the chaotic time series. The EELM inherits the basic idea of extreme learning machine (ELM) in training single hidden layer feedforward networks, but replaces the commonly used singular value decomposition with a reduced complete orthogonal decomposition to calculate the output weights, which can achieve a much faster learning speed than ELM. Moreover, in order to obtain a more accurate and more stable prediction performance for chaotic time series prediction, this model abandons the traditional two-stage modeling approach and adopts an integrated parameter selection strategy which employs a modified DE algorithm to optimize the phase space reconstruction parameters of chaotic time series and the model parameter of EELM simultaneously based on a hybrid validation criterion. Experimental results show that the proposed integrated prediction model can not only provide stable prediction performances with high efficiency but also achieve much more accurate prediction results than its counterparts for chaotic time series prediction.     

Nonlinear regression in environmental sciences using extreme learning machines: A comparative evaluation

The extreme learning machine (ELM), a single-hidden layer feedforward neural network algorithm, was tested on nine environmental regression problems. The prediction accuracy and computational speed of the ensemble ELM were evaluated against multiple linear regression (MLR) and three nonlinear machine learning (ML) techniques – artificial neural network (ANN), support vector regression and random forest (RF). Simple automated algorithms were used to estimate the parameters (e.g. number of hidden neurons) needed for model training. Scaling the range of the random weights in ELM improved its performance. Excluding large datasets (with large number of cases and predictors), ELM tended to be the fastest among the nonlinear models. For large datasets, RF tended to be the fastest. ANN and ELM had similar skills, but ELM was much faster than ANN except for large datasets. Generally, the tested ML techniques outperformed MLR, but no single method was best for all the nine datasets.     

Enhanced combination modeling method for combustion efficiency in coal-fired boilers

In this paper, we propose a new combination modeling method whose structure consists of three components: extreme learning machine (ELM), adaptive neuro-fuzzy inference system (ANFIS) and PS-ABC which is a modified hybrid artificial bee colony algorithm. The combination modeling method has been proposed in an attempt to obtain good approximations and generalization performances. In the whole model, ELM is used to build a global model, and ANFIS is applied to compensate the output errors of ELM model to improve the overall performance. In order to obtain a better generalization ability and stability model, PS-ABC is adopted to optimize input weights and biases of ELM. For stating the proposed model validity, it is applied to set up the mapping relation between the boiler efficiency and operational conditions of a 300 WM coal-fired boiler. Compared with other combination models, the proposed model shows better approximations and generalization performances.     

An Ensemble ELM Based on Modified AdaBoost.RT Algorithm for Predicting the Temperature of Molten Steel in Ladle Furnace

Combined the modified AdaBoost.RT with extreme learning machine (ELM), a new hybrid artificial intelligent technique called ensemble ELM is developed for regression problem in this study. First, a new ELM algorithm is selected as ensemble predictor due to its rapid speed and good performance. Second, a modified AdaBoost.RT is proposed to overcome the limitation of original AdaBoost.RT by self-adaptively modifying the threshold value. Then, an ensemble ELM is presented by using the modified AdaBoost.RT for better accuracy of predictability than individual method. Finally, this new hybrid intelligence method is used to establish a temperature prediction model of molten steel by analyzing the metallurgic process of ladle furnace (LF). The model is examined by data of production from 300t LF in Baoshan Iron and Steel Co., Ltd. and compared with the models that established by single ELM, GA-BP (combined genetic algorithm with BP network), and original AdaBoost.RT. The experiments demonstrated that the hybrid intelligence method can improved generalization performance and boost the accuracy, and the accuracy of the temperature prediction is satisfied for the process of practical producing.     

基于带惩罚因子椭球定界算法的软测量建模

软测量模型的预测精度和泛化性能是软测量建模的2个重要指标。基于最优定界椭球的极限学习机算法(OBE-ELM)虽然克服了传统极限学习机建模预测精度不高、预测结果不稳定等缺点,但是传统OBE算法仅考虑模型误差最小化,未考虑模型的复杂程度,导致模型易出现过拟合现象。基于上述问题,首先针对噪声未知但有界的非线性系统,提出了一种带惩罚项的椭球定界算法(POBE),在模型误差中加入惩罚项起到抑制参数增长太大和驱使不重要参数逐渐减小到零的作用,然后将POBE应用到ELM模型参数优化过程中。最后在信道参数估计实验和连续搅拌反应釜数据集上分别验证POBE及POBE-ELM有效性。     

Surface reconstruction based on extreme learning machine

In this paper, extreme learning machine (ELM) is used to reconstruct a surface with a high speed. It is shown that an improved ELM, called polyharmonic extreme learning machine (P-ELM), is proposed to reconstruct a smoother surface with a high accuracy and robust stability. The proposed P-ELM improves ELM in the sense of adding a polynomial in the single-hidden-layer feedforward networks to approximate the unknown function of the surface. The proposed P-ELM can not only retain the advantages of ELM with an extremely high learning speed and a good generalization performance but also reflect the intrinsic properties of the reconstructed surface. The detailed comparisons of the P-ELM, RBF algorithm, and ELM are carried out in the simulation to show the good performances and the effectiveness of the proposed algorithm.     

基于结合混沌纵横交叉的粒子群算法优化极限学习机的短期负荷预测

为了解决传统的单一负荷预测模型精度低以及常规智能算法在解决高维、多模复杂问题时容易陷入局部最优的问题,提出了一种结合混沌纵横交叉的粒子群算法（CC-PSO）优化极限学习机(ELM)的短期负荷预测模型。ELM的泛化能力与其输入权值和隐含层偏置密切相关,采用结合混沌纵横交叉的粒子群算法优化ELM的输入权值与隐含层偏置,提高了ELM的泛化能力和预测精度。选择广东某地区实际电网负荷数据进行分析,研究结果表明,相对于BP神经网络和支持向量机,ELM具有更高的泛化能力和预测精度;CC-PSO相对于粒子群和遗传算法具有更高的全局搜索能力,CC-PSO-ELM模型具有较高的负荷预测精度。     

融合极端学习机的判别性分析字典学习算法

研究表明,端学习机和判别性字典学习算法在图像分类领域极具有高效和准确的优势。然而,这两种方法也具有各自的缺点,极端学习机对噪声的鲁棒性较差,判别性字典学习算法在分类过程中耗时较长。为统一这种互补性以提高分类性能,文中提出了一种融合极端学习机的判别性分析字典学习模型。该模型利用迭代优化算法学习最优的判别性分析字典和极端学习机分类器。为验证所提算法的有效性,利用人脸数据集进行分类。实验结果表明,与目前较为流行的字典学习算法和极端学习机相比,所提算法在分类过程中具有更好的效果。