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Multivariable Dynamic Modeling for Molten Iron Quality Using Incremental Random Vector Functional-link Networks 被引量:4
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作者 Li ZHANG Ping ZHOU +2 位作者 He-da SONG Meng YUAN Tian-you CHAI 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2016年第11期1151-1159,共9页
Molten iron temperature as well as Si, P, and S contents is the most essential molten iron quality (MIQ) indices in the blast furnace (BF) ironmaking, which requires strict monitoring during the whole ironmaking p... Molten iron temperature as well as Si, P, and S contents is the most essential molten iron quality (MIQ) indices in the blast furnace (BF) ironmaking, which requires strict monitoring during the whole ironmaking production. However, these MIQ parameters are difficult to be directly measured online, and large-time delay exists in off-line analysis through laboratory sampling. Focusing on the practical challenge, a data-driven modeling method was presented for the prediction of MIQ using the improved muhivariable incremental random vector functional-link net- works (M-I-RVFLNs). Compared with the conventional random vector functional-link networks (RVFLNs) and the online sequential RVFLNs, the M-I-RVFLNs have solved the problem of deciding the optimal number of hidden nodes and overcome the overfitting problems. Moreover, the proposed M I RVFLNs model has exhibited the potential for multivariable prediction of the MIQ and improved the terminal condition for the multiple-input multiple-out- put (MIMO) dynamic system, which is suitable for the BF ironmaking process in practice. Ultimately, industrial experiments and contrastive researches have been conducted on the BF No. 2 in Liuzhou Iron and Steel Group Co. Ltd. of China using the proposed method, and the results demonstrate that the established model produces better estima ting accuracy than other MIQ modeling methods. 展开更多
关键词 molten iron quality multivariable incremental random vector functional-link network blast furnace iron-making data-driven modeling principal component analysis
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Dispersion of the Mechanical Parts Performance Indicators Based on the Concept of Random Vector 被引量:1
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作者 XIA Changgao ZHU Pei +2 位作者 ZHANG Meng GAO Xiang LU Liling 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第1期153-159,共7页
To solve the precision and reliability problem of various machinery equipments and military vehicles, some military organisations, the industrial sector and the academia at home and abroad begin to pay attention to th... To solve the precision and reliability problem of various machinery equipments and military vehicles, some military organisations, the industrial sector and the academia at home and abroad begin to pay attention to the statistical distribution of machining dimensions, material properties and service loads, and the system reliability optimization design with constraints and reliability optimization design of various mechanical parts is studied in this way. However, the above researches focus on solving the strength and the life problem, and no studies have been done on the discrete degree and discrete pattern of other performance indicators. The concept of using a random vector to describe the mechanical parts performance indicators is presented; characteristics between the value of the vector variance matrix determinant and the sum of the diagonal covariance matrix in describing the performance indicators of vector dispersion are studied and compared. A clutch diaphragm spring is set as an example, the geometric dimension indicator is described with random vector, and the applicability of using variance matrix determinant and variance matrix trace of geometric dimension vector to describe discrete degree of random vector is studied by using Monte-Carlo simulation method and component discrete degree perturbation method. Also, the effects of different components of diaphragm spring geometric dimension vector on the value of covariance matrix determinant and the sum of covariance matrix diagonal of diaphragm spring performance indicators vector are analyzed. The present study shows that the impacts of the dispersion of diaphragm spring cone angle on every performance dispersion are all ranked first, and far exceed that of other dimension dispersion. So it must be strictly controlled in the production process. The result of the research work provides a reference for the design of diaphragm spring, and also it presents a proper method for researching the performance of other mechanical parts. 展开更多
关键词 diaphragm spring random vector DISPERSION
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Underwater Image Classification Based on EfficientnetB0 and Two-Hidden-Layer Random Vector Functional Link
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作者 ZHOU Zhiyu LIU Mingxuan +2 位作者 JI Haodong WANG Yaming ZHU Zefei 《Journal of Ocean University of China》 CAS CSCD 2024年第2期392-404,共13页
The ocean plays an important role in maintaining the equilibrium of Earth’s ecology and providing humans access to a wealth of resources.To obtain a high-precision underwater image classification model,we propose a c... The ocean plays an important role in maintaining the equilibrium of Earth’s ecology and providing humans access to a wealth of resources.To obtain a high-precision underwater image classification model,we propose a classification model that combines an EfficientnetB0 neural network and a two-hidden-layer random vector functional link network(EfficientnetB0-TRVFL).The features of underwater images were extracted using the EfficientnetB0 neural network pretrained via ImageNet,and a new fully connected layer was trained on the underwater image dataset using the transfer learning method.Transfer learning ensures the initial performance of the network and helps in the development of a high-precision classification model.Subsequently,a TRVFL was proposed to improve the classification property of the model.Net construction of the two hidden layers exhibited a high accuracy when the same hidden layer nodes were used.The parameters of the second hidden layer were obtained using a novel calculation method,which reduced the outcome error to improve the performance instability caused by the random generation of parameters of RVFL.Finally,the TRVFL classifier was used to classify features and obtain classification results.The proposed EfficientnetB0-TRVFL classification model achieved 87.28%,74.06%,and 99.59%accuracy on the MLC2008,MLC2009,and Fish-gres datasets,respectively.The best convolutional neural networks and existing methods were stacked up through box plots and Kolmogorov-Smirnov tests,respectively.The increases imply improved systematization properties in underwater image classification tasks.The image classification model offers important performance advantages and better stability compared with existing methods. 展开更多
关键词 underwater image classification EfficientnetB0 random vector functional link convolutional neural network
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Fully Distributed Learning for Deep Random Vector Functional-Link Networks
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作者 Huada Zhu Wu Ai 《Journal of Applied Mathematics and Physics》 2024年第4期1247-1262,共16页
In the contemporary era, the proliferation of information technology has led to an unprecedented surge in data generation, with this data being dispersed across a multitude of mobile devices. Facing these situations a... In the contemporary era, the proliferation of information technology has led to an unprecedented surge in data generation, with this data being dispersed across a multitude of mobile devices. Facing these situations and the training of deep learning model that needs great computing power support, the distributed algorithm that can carry out multi-party joint modeling has attracted everyone’s attention. The distributed training mode relieves the huge pressure of centralized model on computer computing power and communication. However, most distributed algorithms currently work in a master-slave mode, often including a central server for coordination, which to some extent will cause communication pressure, data leakage, privacy violations and other issues. To solve these problems, a decentralized fully distributed algorithm based on deep random weight neural network is proposed. The algorithm decomposes the original objective function into several sub-problems under consistency constraints, combines the decentralized average consensus (DAC) and alternating direction method of multipliers (ADMM), and achieves the goal of joint modeling and training through local calculation and communication of each node. Finally, we compare the proposed decentralized algorithm with several centralized deep neural networks with random weights, and experimental results demonstrate the effectiveness of the proposed algorithm. 展开更多
关键词 Distributed Optimization Deep Neural Network random vector Functional-Link (RVFL) Network Alternating Direction Method of Multipliers (ADMM)
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The Estimation of Radial Exponential Random Vectors in Additive White Gaussian Noise
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作者 Pichid KITTISUWAN Sanparith MARUKATAT Widhyakorn ASDORNWISED 《Wireless Sensor Network》 2009年第4期284-292,共9页
Image signals are always disturbed by noise during their transmission, such as in mobile or network communication. The received image quality is significantly influenced by noise. Thus, image signal denoising is an in... Image signals are always disturbed by noise during their transmission, such as in mobile or network communication. The received image quality is significantly influenced by noise. Thus, image signal denoising is an indispensable step during image processing. As we all know, most commonly used methods of image denoising is Bayesian wavelet transform estimators. The Performance of various estimators, such as maximum a posteriori (MAP), or minimum mean square error (MMSE) is strongly dependent on correctness of the proposed model for original data distribution. Therefore, the selection of a proper model for distribution of wavelet coefficients is important in wavelet-based image denoising. This paper presents a new image denoising algorithm based on the modeling of wavelet coefficients in each subband with multivariate Radial Exponential probability density function (PDF) with local variances. Generally these multivariate extensions do not result in a closed form expression, and the solution requires numerical solutions. However, we drive a closed form MMSE shrinkage functions for a Radial Exponential random vectors in additive white Gaussian noise (AWGN). The estimator is motivated and tested on the problem of wavelet-based image denoising. In the last, proposed, the same idea is applied to the dual-tree complex wavelet transform (DT-CWT), This Transform is an over-complete wavelet transform. 展开更多
关键词 MMSE ESTIMATOR RADIAL EXPONENTIAL random vectorS Wavelet Transform Image DENOISING
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Law of large numbers for m-dependent random vectors under sublinear expectations
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作者 Mingcong Wu Guanghui Cheng 《Probability, Uncertainty and Quantitative Risk》 2025年第1期1-12,共12页
Sublinear expectation relaxes the linear property of classical expectation to subadditivity and positive homogeneity,which can be expressed as E(·)=sup_(θ∈θ) E_(θ)(·)for a certain set of linear expectati... Sublinear expectation relaxes the linear property of classical expectation to subadditivity and positive homogeneity,which can be expressed as E(·)=sup_(θ∈θ) E_(θ)(·)for a certain set of linear expectations{E_(θ):θ∈θ}.Such a framework can capture the uncertainty and facilitate a robust method of measuring risk loss reasonably.This study established a law of large numbers for m-dependent random vectors within the framework of sublinear expectation.Consequently,the corresponding explicit rate of convergence were derived.The results of this study can be considered as an extension of the Peng's law of large numbers[22]. 展开更多
关键词 Law of large numbers m-dependence Sublinear expectations Rate of convergence random vectors
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Some Convergence Properties for Weighted Sums of Martingale Difference Random Vectors
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作者 Yi WU Xue Jun WANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2024年第4期1127-1142,共16页
Let{X_(ni),F_(ni);1≤i≤n,n≥1}be an array of R^(d)martingale difference random vectors and{A_(ni),1≤i≤n,n≥1}be an array of m×d matrices of real numbers.In this paper,the Marcinkiewicz-Zygmund type weak law of... Let{X_(ni),F_(ni);1≤i≤n,n≥1}be an array of R^(d)martingale difference random vectors and{A_(ni),1≤i≤n,n≥1}be an array of m×d matrices of real numbers.In this paper,the Marcinkiewicz-Zygmund type weak law of large numbers for maximal weighted sums of martingale difference random vectors is obtained with not necessarily finite p-th(1<p<2)moments.Moreover,the complete convergence and strong law of large numbers are established under some mild conditions.An application to multivariate simple linear regression model is also provided. 展开更多
关键词 Martingale difference random vectors weighted sums Marcinkiewicz–Zygmund type weak law of large numbers complete convergence strong law of large numbers multivariate simple linear regression model
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基于Vector Random Decrement技术和特征系统实现算法ERA的模态参数识别
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作者 杨陈 孙阳 《世界地震工程》 CSCD 北大核心 2013年第4期102-107,共6页
现代的大型复杂结构,如大坝、高层建筑、桥梁及海洋平台等,处于复杂的环境载荷作用下,这些环境载荷往往是无法测量的。在仅有输出响应时,应用随机减量法RDT获得自由衰减响应信号,而后用时域复指数拟合法、ITD法、特征系统实现算法ERA等... 现代的大型复杂结构,如大坝、高层建筑、桥梁及海洋平台等,处于复杂的环境载荷作用下,这些环境载荷往往是无法测量的。在仅有输出响应时,应用随机减量法RDT获得自由衰减响应信号,而后用时域复指数拟合法、ITD法、特征系统实现算法ERA等算法获得结构的模态参数是一种有效的方法。但在数据量有限时,随机减量函数的平均次数过少,导致RD函数的收敛性较差。为此提出了利用Vector Random Decrement技术(VRDT)提取自由衰减响应信号,而后利用特征系统实现算法ERA求得模态参数的方法,新算法能够有效地提高模态参数识别精度。数值算例验证了所提算法的有效性。 展开更多
关键词 向量随机减量技术 特征系统实现算法 模态分析
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ON THE EXPECTATION AND VARIANCE OF HAMMING DISTANCE BETWEEN TWO I.I.D RANDOM VECTORS
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作者 符方伟 沈世镒 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 1997年第3期243-250,共6页
By using the generalized MacWilliams theorem, we give new representations for expectation and variance of Hamming distance between two i.i.d random vectors. By using the new representations, we derive a lower bound fo... By using the generalized MacWilliams theorem, we give new representations for expectation and variance of Hamming distance between two i.i.d random vectors. By using the new representations, we derive a lower bound for the variance, and present a simple and direct proof of the inequality of [1]. 展开更多
关键词 Hamming distance random vector EXPECTATION variance generalized MacWilliams theorem
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Basic Tenets of Classification Algorithms K-Nearest-Neighbor, Support Vector Machine, Random Forest and Neural Network: A Review 被引量:15
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作者 Ernest Yeboah Boateng Joseph Otoo Daniel A. Abaye 《Journal of Data Analysis and Information Processing》 2020年第4期341-357,共17页
In this paper, sixty-eight research articles published between 2000 and 2017 as well as textbooks which employed four classification algorithms: K-Nearest-Neighbor (KNN), Support Vector Machines (SVM), Random Forest (... In this paper, sixty-eight research articles published between 2000 and 2017 as well as textbooks which employed four classification algorithms: K-Nearest-Neighbor (KNN), Support Vector Machines (SVM), Random Forest (RF) and Neural Network (NN) as the main statistical tools were reviewed. The aim was to examine and compare these nonparametric classification methods on the following attributes: robustness to training data, sensitivity to changes, data fitting, stability, ability to handle large data sizes, sensitivity to noise, time invested in parameter tuning, and accuracy. The performances, strengths and shortcomings of each of the algorithms were examined, and finally, a conclusion was arrived at on which one has higher performance. It was evident from the literature reviewed that RF is too sensitive to small changes in the training dataset and is occasionally unstable and tends to overfit in the model. KNN is easy to implement and understand but has a major drawback of becoming significantly slow as the size of the data in use grows, while the ideal value of K for the KNN classifier is difficult to set. SVM and RF are insensitive to noise or overtraining, which shows their ability in dealing with unbalanced data. Larger input datasets will lengthen classification times for NN and KNN more than for SVM and RF. Among these nonparametric classification methods, NN has the potential to become a more widely used classification algorithm, but because of their time-consuming parameter tuning procedure, high level of complexity in computational processing, the numerous types of NN architectures to choose from and the high number of algorithms used for training, most researchers recommend SVM and RF as easier and wieldy used methods which repeatedly achieve results with high accuracies and are often faster to implement. 展开更多
关键词 Classification Algorithms NON-PARAMETRIC K-Nearest-Neighbor Neural Networks random Forest Support vector Machines
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The Comparison between Random Forest and Support Vector Machine Algorithm for Predicting β-Hairpin Motifs in Proteins
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作者 Shaochun Jia Xiuzhen Hu Lixia Sun 《Engineering(科研)》 2013年第10期391-395,共5页
Based on the research of predictingβ-hairpin motifs in proteins, we apply Random Forest and Support Vector Machine algorithm to predictβ-hairpin motifs in ArchDB40 dataset. The motifs with the loop length of 2 to 8 ... Based on the research of predictingβ-hairpin motifs in proteins, we apply Random Forest and Support Vector Machine algorithm to predictβ-hairpin motifs in ArchDB40 dataset. The motifs with the loop length of 2 to 8 amino acid residues are extracted as research object and thefixed-length pattern of 12 amino acids are selected. When using the same characteristic parameters and the same test method, Random Forest algorithm is more effective than Support Vector Machine. In addition, because of Random Forest algorithm doesn’t produce overfitting phenomenon while the dimension of characteristic parameters is higher, we use Random Forest based on higher dimension characteristic parameters to predictβ-hairpin motifs. The better prediction results are obtained;the overall accuracy and Matthew’s correlation coefficient of 5-fold cross-validation achieve 83.3% and 0.59, respectively. 展开更多
关键词 random FOREST ALGORITHM Support vector Machine ALGORITHM β-Hairpin MOTIF INCREMENT of Diversity SCORING Function Predicted Secondary Structure Information
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Efficient Global Threshold Vector Outlyingness Ratio Filter for the Removal of Random Valued Impulse Noise
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作者 J. Amudha R. Sudhakar 《Circuits and Systems》 2016年第6期692-700,共9页
This research paper proposes a filter to remove Random Valued Impulse Noise (RVIN) based on Global Threshold Vector Outlyingness Ratio (GTVOR) that is applicable for real time image processing. This filter works with ... This research paper proposes a filter to remove Random Valued Impulse Noise (RVIN) based on Global Threshold Vector Outlyingness Ratio (GTVOR) that is applicable for real time image processing. This filter works with the algorithm that breaks the images into various decomposition levels using Discrete Wavelet Transform (DWT) and searches for the noisy pixels using the outlyingness of the pixel. This algorithm has the capability of differentiating high frequency pixels and the “noisy pixel” using the threshold as well as window adjustments. The damage and the loss of information are prevented by means of interior mining. This global threshold based algorithm uses different thresholds for different quadrants of DWT and thus helps in recovery of noisy image even if it is 90% affected. Experimental results exhibit that this method outperforms other existing methods for accurate noise detection and removal, at the same time chain of connectivity is not lost. 展开更多
关键词 Image Restoration Noise Detection Noise Removal random Valued Impulse Noise Global Threshold vector Outlyingness Ratio
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基于机器学习算法的地层孔隙压力预测模型构建与应用
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作者 孙小芳 蒋荻南 +3 位作者 金亚 侯晓东 孙志峰 王储 《测井技术》 2026年第1期163-171,共9页
传统地层孔隙压力预测方法在复杂地质条件下普适性低、计算流程复杂,难以满足工程现场对参数快速精准获取的需求。为解决该问题,以某实际勘探区块为研究对象,构建了随机森林、支持向量机、多元线性回归及神经网络这4种机器学习预测模型... 传统地层孔隙压力预测方法在复杂地质条件下普适性低、计算流程复杂,难以满足工程现场对参数快速精准获取的需求。为解决该问题,以某实际勘探区块为研究对象,构建了随机森林、支持向量机、多元线性回归及神经网络这4种机器学习预测模型,开展了地层孔隙压力的智能预测与对比研究。在方法设计上,优选出井深、地层密度、纵波时差、横波时差、自然伽马这5项关键测井数据作为模型输入,将经现场测压数据校正的孔隙压力值作为标定参数,建立了地层孔隙压力智能预测模型并进行了性能验证。结果表明:随机森林算法的预测性能最优,其平均绝对误差和标准差分别低至0.026 g/cm^(3)和0.044 g/cm^(3),且在岩性突变、构造异常段仍保持稳定预测效果;相比之下,支持向量机模型存在一定的系统性偏差,多元线性回归难以拟合孔隙压力与测井曲线之间的非线性关系,神经网络在局部异常段存在偏差。进一步的敏感性分析表明,模型结构与参数不变时,预测准确度与训练数据集规模、目标参数(孔隙压力)取值的覆盖范围呈显著正相关。结论认为:机器学习预测方法可有效突破传统技术局限,随机森林算法综合表现最佳,在实际应用中可优先采用;为确保模型预测效能最大化,实际应用中需广泛收集工区内具有代表性的井资料,构建涵盖完整压力区间的高质量训练数据集,从而为钻井工程设计、安全钻进与地质灾害防控提供更为可靠、高效的参数支持。 展开更多
关键词 地层孔隙压力 随机森林 支持向量机 多元线性回归 神经网络 声波时差 地层密度 自然伽马
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A RANDOM TRANSPORT-DIFFUSION EQUATION 被引量:1
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作者 胡耀忠 《Acta Mathematica Scientia》 SCIE CSCD 2010年第6期2033-2050,共18页
In this paper we study the integral curve in a random vector field perturbed by white noise. It is related to a stochastic transport-diffusion equation. Under some conditions on the covariance function of the vector f... In this paper we study the integral curve in a random vector field perturbed by white noise. It is related to a stochastic transport-diffusion equation. Under some conditions on the covariance function of the vector field, the solution of this stochastic partial differential equation is proved to have moments. The exact p-th moment is represented through integrals with respect to Brownian motions. The basic tool is Girsanov formula. 展开更多
关键词 random vector field chaos expansion random transport-diffusion equation TRACE exponential of quadratic functional of Gaussian field
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基于改进的Random Subspace 的客户投诉分类方法 被引量:3
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作者 杨颖 王珺 王刚 《计算机工程与应用》 CSCD 北大核心 2020年第13期230-235,共6页
电信业的客户投诉不断增多而又亟待高效处理。针对电信客户投诉数据的特点,提出了一种面向高维数据的改进的集成学习分类方法。该方法综合考虑客户投诉中的文本信息及客户通讯状态信息,基于Random Subspace方法,以支持向量机(Support Ve... 电信业的客户投诉不断增多而又亟待高效处理。针对电信客户投诉数据的特点,提出了一种面向高维数据的改进的集成学习分类方法。该方法综合考虑客户投诉中的文本信息及客户通讯状态信息,基于Random Subspace方法,以支持向量机(Support Vector Machine,SVM)为基分类器,采用证据推理(Evidential Reasoning,ER)规则为一种新的集成策略,构造分类模型对电信客户投诉进行分类。所提模型和方法在某电信公司客户投诉数据上进行了验证,实验结果显示该方法能够显著提高客户投诉分类的准确率和投诉处理效率。 展开更多
关键词 客户投诉分类 random Subspace方法 支持向量机 证据推理规则
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基于采样噪声随机数的三电平逆变器低EMI电压调制技术
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作者 边泽宇 MANZAR HUSSAIN +2 位作者 田兵 谭强 王涛 《电气工程学报》 北大核心 2026年第1期220-229,共10页
在大功率电机驱动系统中,逆变器功率器件高速开关伴随着较高的电压变化率,由此产生高频电磁干扰(Electromagnetic interference,EMI),并通过辐射和寄生参数等耦合路径对电机控制系统产生影响。多电平逆变器能一定程度上降低电压变化率,... 在大功率电机驱动系统中,逆变器功率器件高速开关伴随着较高的电压变化率,由此产生高频电磁干扰(Electromagnetic interference,EMI),并通过辐射和寄生参数等耦合路径对电机控制系统产生影响。多电平逆变器能一定程度上降低电压变化率,改善电磁兼容性,但对于传统空间矢量脉宽调制(Space vector pulse width modulation,SVPWM),集中在载波频率附近的谐波峰值仍然较大。提出一种三电平逆变器双随机SVPWM策略,将随机载波频率和随机冗余小矢量相结合,并通过采样噪声获取真随机数作为随机因子,增强随机效果。在不影响矢量控制运行性能的情况下,将集中在载波频率及其整数倍处的高次谐波分散到整个频域内,有效降低了高频谐波的幅值,使得输出电压的频谱更加均匀连续,从而降低了系统EMI。最后通过试验验证了所提方法的有效性。 展开更多
关键词 三电平逆变器 随机开关频率 随机冗余矢量 功率谱密度 采样噪声
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基于多光谱与热红外影像的烤烟地土壤含水率反演
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作者 查宏波 赵芳 +5 位作者 王力 陈嘉航 徐凯 王海东 杨启良 吴立峰 《节水灌溉》 北大核心 2026年第3期26-33,41,共9页
为实现烤烟地土壤含水率快速精准监测,以云南省昭通市巧家县蒙姑镇拖坑村9块烤烟试验田为研究区,结合多光谱、热红外无人机影像与机器学习模型开展反演研究。获取DJI Mavic 3多光谱无人机(4波段,分辨率0.003 m)、DJI Matrice 4T热红外... 为实现烤烟地土壤含水率快速精准监测,以云南省昭通市巧家县蒙姑镇拖坑村9块烤烟试验田为研究区,结合多光谱、热红外无人机影像与机器学习模型开展反演研究。获取DJI Mavic 3多光谱无人机(4波段,分辨率0.003 m)、DJI Matrice 4T热红外无人机(VOx传感器,分辨率0.005 m)影像,以及土壤体积含水率数据。经ENVI与Pix4D预处理影像,提取多光谱敏感特征(9个)并结合热红外DN值构建特征集,采用随机森林、支持向量机、极端梯度提升、卷积神经网络算法构建单源/多源反演模型,以均方根误差(RMSE)与决定系数(R^(2))评估精度。结果表明:多源模型精度显著优于单源,RF在多光谱+DN输入下最优(RMSE=1.30%、R^(2)=0.79),XGBoost性能与其接近(RMSE=1.31%、R^(2)=0.78);SHAP分析显示NREI、NDVI_RVI及热红外DN值为关键特征。研究证实多光谱与热红外无人机影像协同机器学习可高效反演烤烟地土壤含水率,为产区精准灌溉与水资源管理提供技术支撑。 展开更多
关键词 无人机 机器学习 随机森林 支持向量机 XGBoost 卷积神经网 土壤含水率反演 多光谱 热红外 数据融合
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基于改进Stacking集成学习的深层油井管腐蚀预测
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作者 黄晗 陈长风 +3 位作者 贾小兰 张玉洁 石丽伟 王立群 《深圳大学学报(理工版)》 北大核心 2026年第1期7-16,I0001,共11页
为提升深层复杂环境下油井管平均腐蚀与点蚀速率的预测精度,并优化传统Stacking集成学习未充分考虑基学习器异质性的问题,提出了一种基于决定系数R2的改进Stacking集成学习算法.该算法集成了XGBoost(extreme gradient boosting)模型、... 为提升深层复杂环境下油井管平均腐蚀与点蚀速率的预测精度,并优化传统Stacking集成学习未充分考虑基学习器异质性的问题,提出了一种基于决定系数R2的改进Stacking集成学习算法.该算法集成了XGBoost(extreme gradient boosting)模型、随机森林(random forest,RF)模型、支持向量回归(support vector regression,SVR)模型和梯度提升决策树(gradient boosting decision tree,GBDT)模型4种机器学习算法作为基学习器,并基于决定系数R2为基学习器的输出结果进行权重赋值,作为元学习器的输入数据集.实验结果显示,与传统Stacking集成方法相比,改进后的模型在平均腐蚀速率预测上,平均绝对误差和均方误差分别降低了25.9%和9.7%,决定系数提高了2.3%;在点蚀速率预测上,平均绝对误差和均方误差分别降低了11.6%和2.0%,决定系数提高了2.7%,证明了本算法的有效性.研究成果可为深层油井管腐蚀防控与安全运维提供支撑. 展开更多
关键词 腐蚀科学与防护 Stacking集成学习 深层油井管材腐蚀 机器学习 XGBoost 随机森林 支持向量回归 梯度提升决策树
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基于边缘计算和模糊RVFL网络的输油气管道故障分类
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作者 张黎 《控制工程》 北大核心 2026年第1期66-72,共7页
针对输油气管道的故障种类多、现场数据无法长期有效保存等问题,提出了一种基于边缘计算和改进随机向量函数链接(random vector functional-link,RVFL)网络的输油气管道故障分类方法。该方法扩展了监控和数据采集(supervisory control a... 针对输油气管道的故障种类多、现场数据无法长期有效保存等问题,提出了一种基于边缘计算和改进随机向量函数链接(random vector functional-link,RVFL)网络的输油气管道故障分类方法。该方法扩展了监控和数据采集(supervisory control and data acquisition,SCADA)系统的功能,使其可以存储和访问大量的数据。首先,当输油气管道出现故障时,利用基于模糊似然函数的模糊聚类算法对故障发生前一段时间内的管道压力值进行聚类;然后,提取管道压力值密度特征,将其作为RVFL网络的增强节点,利用改进RVFL网络对故障进行分类。将改进RVFL网络部署在边缘计算模块中,对6种故障进行分类,其准确率可达到96.7%。 展开更多
关键词 边缘计算 模糊似然函数 聚类 随机向量函数链接网络 故障分类
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基于零点分布特征的自耦变压器绕组故障诊断
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作者 钱国超 何顺 +3 位作者 刘红文 胡锦 杨坤 王东阳 《电力工程技术》 北大核心 2026年第3期73-84,共12页
绕组故障是变压器发生事故的主要原因之一,有效掌握变压器绕组状态具有重要意义。文中针对自耦变压器(autotransformer,AT)绕组故障诊断开展研究。首先,搭建试验平台模拟AT多种典型的绕组单一故障及多重故障,测试得到不同故障类型、程... 绕组故障是变压器发生事故的主要原因之一,有效掌握变压器绕组状态具有重要意义。文中针对自耦变压器(autotransformer,AT)绕组故障诊断开展研究。首先,搭建试验平台模拟AT多种典型的绕组单一故障及多重故障,测试得到不同故障类型、程度下的频率响应;其次,利用快速矢量匹配法拟合得到绕组正常及故障下AT绕组系统的传递函数,从而得到极坐标形式下的零点分布图;然后,对零点分布图进行灰度差分统计(gray level difference statistics,GLDS)特征和灰度梯度共生矩阵(gray-gradient co-occurrence matrix,GGCM)特征的提取,并结合基于粒子群优化(particle swarm optimization,PSO)的随机森林(random forest,RF)算法实现对故障绕组和故障类型的分类;最后,基于实际AT故障案例对所提方法进行验证分析。结果表明,综合幅频和相频信息、通过快速矢量匹配拟合获取的极坐标形式下的零点分布图可捕捉到原始频响曲线中的较小差异;相较于布谷鸟算法、遗传算法等优化算法,基于PSO的RF算法对AT故障绕组和故障类型的识别准确率始终保持在93%以上,并且在实际AT故障案例中,文中所提诊断方法的分析结果与吊罩检修结果一致。 展开更多
关键词 自耦变压器(AT) 频率响应分析 零点分布 多重故障 矢量匹配 随机森林(RF)
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