期刊文献+
共找到8,065篇文章
< 1 2 250 >
每页显示 20 50 100
Corrigendum to“Mean-Squared Energy Difference for Exploring Potential Energy Landscapes of Supercooled Liquids”
1
作者 D.M.Zhang D.Y.Sun X.G.Gong 《Chinese Physics Letters》 2025年第5期248-248,共1页
Equations(2)and(6)and the corresponding discussion in the paper[Chin.Phys.Lett.42,056301(2025)]have been corrected.These modiffcations do not affect the results derived in the paper.
关键词 potential energy landscapes EQUATIONS CORRECTIONS mean squared energy difference supercooled liquids
原文传递
Enhanced kernel minimum squared error algorithm and its application in face recognition
2
作者 赵英男 何祥健 +1 位作者 陈北京 赵晓平 《Journal of Southeast University(English Edition)》 EI CAS 2016年第1期35-38,共4页
To improve the classification performance of the kernel minimum squared error( KMSE), an enhanced KMSE algorithm( EKMSE) is proposed. It redefines the regular objective function by introducing a novel class label ... To improve the classification performance of the kernel minimum squared error( KMSE), an enhanced KMSE algorithm( EKMSE) is proposed. It redefines the regular objective function by introducing a novel class label definition, and the relative class label matrix can be adaptively adjusted to the kernel matrix.Compared with the common methods, the newobjective function can enlarge the distance between different classes, which therefore yields better recognition rates. In addition, an iteration parameter searching technique is adopted to improve the computational efficiency. The extensive experiments on FERET and GT face databases illustrate the feasibility and efficiency of the proposed EKMSE. It outperforms the original MSE, KMSE,some KMSE improvement methods, and even the sparse representation-based techniques in face recognition, such as collaborate representation classification( CRC). 展开更多
关键词 minimum squared error kernel minimum squared error pattern recognition face recognition
在线阅读 下载PDF
Low Complexity Minimum Mean Square Error Channel Estimation for Adaptive Coding and Modulation Systems 被引量:2
3
作者 GUO Shuxia SONG Yang +1 位作者 GAO Ying HAN Qianjin 《China Communications》 SCIE CSCD 2014年第1期126-137,共12页
Performance of the Adaptive Coding and Modulation(ACM) strongly depends on the retrieved Channel State Information(CSI),which can be obtained using the channel estimation techniques relying on pilot symbol transmissio... Performance of the Adaptive Coding and Modulation(ACM) strongly depends on the retrieved Channel State Information(CSI),which can be obtained using the channel estimation techniques relying on pilot symbol transmission.Earlier analysis of methods of pilot-aided channel estimation for ACM systems were relatively little.In this paper,we investigate the performance of CSI prediction using the Minimum Mean Square Error(MMSE)channel estimator for an ACM system.To solve the two problems of MMSE:high computational operations and oversimplified assumption,we then propose the Low-Complexity schemes(LC-MMSE and Recursion LC-MMSE(R-LC-MMSE)).Computational complexity and Mean Square Error(MSE) are presented to evaluate the efficiency of the proposed algorithm.Both analysis and numerical results show that LC-MMSE performs close to the wellknown MMSE estimator with much lower complexity and R-LC-MMSE improves the application of MMSE estimation to specific circumstances. 展开更多
关键词 adaptive coding and modulation channel estimation minimum mean square error low-complexity minimum mean square error
在线阅读 下载PDF
Wavelet Density Estimation of Censoring Data and Evaluate of Mean Integral Square Error with Convergence Ratio and Empirical Distribution of Given Estimator 被引量:1
4
作者 Mahmoud Afshari 《Applied Mathematics》 2014年第13期2062-2072,共11页
Wavelet has rapid development in the current mathematics new areas. It also has a double meaning of theory and application. In signal and image compression, signal analysis, engineering technology has a wide range of ... Wavelet has rapid development in the current mathematics new areas. It also has a double meaning of theory and application. In signal and image compression, signal analysis, engineering technology has a wide range of applications. In this paper, we use wavelet method, for estimating the density function for censoring data. We evaluate the mean integrated squared error, convergence ratio of given estimator. Also, we obtain empirical distribution of given estimator and verify the conclusion by two simulation examples. 展开更多
关键词 WAVELET Estimation CENSORING mean INTEGRAL error CONVERGENCE
在线阅读 下载PDF
Robust state of charge estimation of lithium-ion battery via mixture kernel mean p-power error loss LSTM with heap-based-optimizer 被引量:1
5
作者 Wentao Ma Yiming Lei +1 位作者 Xiaofei Wang Badong Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第5期768-784,I0016,共18页
The state of charge(SOC)estimation of lithium-ion battery is an important function in the battery management system(BMS)of electric vehicles.The long short term memory(LSTM)model can be employed for SOC estimation,whi... The state of charge(SOC)estimation of lithium-ion battery is an important function in the battery management system(BMS)of electric vehicles.The long short term memory(LSTM)model can be employed for SOC estimation,which is capable of estimating the future changing states of a nonlinear system.Since the BMS usually works under complicated operating conditions,i.e the real measurement data used for model training may be corrupted by non-Gaussian noise,and thus the performance of the original LSTM with the mean square error(MSE)loss may deteriorate.Therefore,a novel LSTM with mixture kernel mean p-power error(MKMPE)loss,called MKMPE-LSTM,is developed by using the MKMPE loss to replace the MSE as the learning criterion in LSTM framework,which can achieve robust SOC estimation under the measurement data contaminated with non-Gaussian noises(or outliers)because of the MKMPE containing the p-order moments of the error distribution.In addition,a meta-heuristic algorithm,called heap-based-optimizer(HBO),is employed to optimize the hyper-parameters(mainly including learning rate,number of hidden layer neuron and value of p in MKMPE)of the proposed MKMPE-LSTM model to further improve its flexibility and generalization performance,and a novel hybrid model(HBO-MKMPE-LSTM)is established for SOC estimation under non-Gaussian noise cases.Finally,several tests are performed under various cases through a benchmark to evaluate the performance of the proposed HBO-MKMPE-LSTM model,and the results demonstrate that the proposed hybrid method can provide a good robustness and accuracy under different non-Gaussian measurement noises,and the SOC estimation results in terms of mean square error(MSE),root MSE(RMSE),mean absolute relative error(MARE),and determination coefficient R2are less than 0.05%,3%,3%,and above 99.8%at 25℃,respectively. 展开更多
关键词 SOC estimation Long short term memory model Mixture kernel mean p-power error Heap-based-optimizer Lithium-ion battery Non-Gaussian noisy measurement data
在线阅读 下载PDF
Efficient Mean Estimation in Log-normal Linear Models with First-order Correlated Errors
6
作者 Zhang Song Wang De-hui 《Communications in Mathematical Research》 CSCD 2013年第3期271-279,共9页
In this paper, we propose a log-normal linear model whose errors are first-order correlated, and suggest a two-stage method for the efficient estimation of the conditional mean of the response variable at the original... In this paper, we propose a log-normal linear model whose errors are first-order correlated, and suggest a two-stage method for the efficient estimation of the conditional mean of the response variable at the original scale. We obtain two estimators which minimize the asymptotic mean squared error (MM) and the asymptotic bias (MB), respectively. Both the estimators are very easy to implement, and simulation studies show that they are perform better. 展开更多
关键词 log-normal first-order correlated maximum likelihood two-stage estimation mean squared error
在线阅读 下载PDF
Mean Square Error Comparisons of Estimatorsin Two SUR Models
7
作者 LIU Jin-shan GUI Qing-ming 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第3期63-71,共9页
For a system of two seerningly umrelated regressions.some general results of mean square er-ror matrix comparisons are presented.A class of linear estimators and a class of two-stage estimatorsbased on a generalized u... For a system of two seerningly umrelated regressions.some general results of mean square er-ror matrix comparisons are presented.A class of linear estimators and a class of two-stage estimatorsbased on a generalized unrestricted estimate of the dispersion matrix are proposed.Some exact finitesample properties of the two-stage estimators are obtained. 展开更多
关键词 seemingly unrelated regressions two-stage estimator mean square error matrix
在线阅读 下载PDF
THE LAW OF THE ITERATED LOGARITHM OF RANDOM WEIGHTING APPROXIMATION FOR MEAN ERROR──NON.I.I.D.SITUATION
8
作者 王炳章 彭建平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1996年第8期741-750,共10页
For the dislribulion if mean error under independent but not identicallydislribuled conditions. its approximating dislribution whose precision reachO is obtained.
关键词 mean error random weight APPROXIMATION
在线阅读 下载PDF
The Relationship between Deterministic and Ensemble Mean Forecast Errors Revealed by Global and Local Attractor Radii
9
作者 Jie FENG Jianping LI +2 位作者 Jing ZHANG Deqiang LIU Ruiqiang DING 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第3期271-278,339,共9页
It has been demonstrated that ensemble mean forecasts, in the context of the sample mean, have higher forecasting skill than deterministic(or single) forecasts. However, few studies have focused on quantifying the rel... It has been demonstrated that ensemble mean forecasts, in the context of the sample mean, have higher forecasting skill than deterministic(or single) forecasts. However, few studies have focused on quantifying the relationship between their forecast errors, especially in individual prediction cases. Clarification of the characteristics of deterministic and ensemble mean forecasts from the perspective of attractors of dynamical systems has also rarely been involved. In this paper, two attractor statistics—namely, the global and local attractor radii(GAR and LAR, respectively)—are applied to reveal the relationship between deterministic and ensemble mean forecast errors. The practical forecast experiments are implemented in a perfect model scenario with the Lorenz96 model as the numerical results for verification. The sample mean errors of deterministic and ensemble mean forecasts can be expressed by GAR and LAR, respectively, and their ratio is found to approach2^(1/2) with lead time. Meanwhile, the LAR can provide the expected ratio of the ensemble mean and deterministic forecast errors in individual cases. 展开更多
关键词 attractor radius ensemble forecasting ensemble mean forecast error saturation
在线阅读 下载PDF
一种基于K-means聚类的最小二乘配置法及在大尺度地壳速度场高精度拟合推估中的应用
10
作者 王程 瞿伟 +3 位作者 李久元 唐兴友 王光耀 杨凯 《大地测量与地球动力学》 北大核心 2025年第12期1294-1303,共10页
针对传统最小二乘配置(traditional least squares collocation,TLSC)算法在大尺度区域地壳运动速度场高精度拟合中,在监测站点稀疏区域与块体边缘处速度场拟合结果会出现异常与不平滑的问题,结合K-means聚类算法与TLSC算法发展了一种基... 针对传统最小二乘配置(traditional least squares collocation,TLSC)算法在大尺度区域地壳运动速度场高精度拟合中,在监测站点稀疏区域与块体边缘处速度场拟合结果会出现异常与不平滑的问题,结合K-means聚类算法与TLSC算法发展了一种基于K-means聚类的最小二乘配置法(KLSC),并在青藏高原GNSS地壳运动实测速度场中验证该方法的有效性。结果表明:1)相较于TLSC算法,KLSC算法利用K-means算法在无监督分类中的优势,基于GNSS速度场本身特征先将研究区域划分为多个速度相似的子区域,然后在每个子区域内分别利用TLSC进行速度场拟合,避免了局部复杂地质环境对区域速度场拟合精度的影响;2)KLSC算法以各网格点到各聚类中心的距离最近为依据选取拟合参数,解决了数据稀疏区域速度场拟合结果较差的问题;3)KLSC算法利用次近距离拟合并结合卷积滤波,有效解决了块体边缘处速度场拟合结果不平滑的问题;4)KLSC算法拟合的速度场的RMSE精度和相关性均优于TLSC算法,东、北向拟合速度场RMSE精度分别提高37%~48.2%和52.1%~67.2%,相关性分别提高24.1%~24.7%和4.7%~5.2%。 展开更多
关键词 GNSS速度场 最小二乘配置算法 K-meanS算法 青藏高原 地壳平滑速度场
在线阅读 下载PDF
基于PCA-Kmeans的电动公交车起步驾驶行为分类与节能行为量化指导 被引量:1
11
作者 王庆宇 《智能计算机与应用》 2025年第5期97-104,共8页
纯电动公交车在动力特性及驾驶操作行为上区别于传统燃油公交车,因此在节能驾驶操作上,应做出相对应的调整。现有研究的节能驾驶建议主要为定性建议,本文提出了一种从数据驱动角度给予定量建议的办法,通过借鉴国家标准GB/T38146中重型... 纯电动公交车在动力特性及驾驶操作行为上区别于传统燃油公交车,因此在节能驾驶操作上,应做出相对应的调整。现有研究的节能驾驶建议主要为定性建议,本文提出了一种从数据驱动角度给予定量建议的办法,通过借鉴国家标准GB/T38146中重型商用车工况构建时的特征参数集,采用主成分分析法(PCA)对特征参数进行降维,采用K-means算法实现驾驶习惯片段的分类提取,根据低功耗片段,选用加速踏板的特征参数,计算得到量化的节能驾驶数值,使用最小二乘法拟合出合适的低功耗速度走势曲线及方程,拟合优度为0.8419,给出一些经济节约指导办法。 展开更多
关键词 数据驱动 新能源汽车 主成分分析法 K-meanS算法 最小二乘法拟合 定量建议
在线阅读 下载PDF
Non-negative least squares variance component estimation of mixed additive and multiplicative random error model
12
作者 Hao Xiao Leyang Wang 《Geodesy and Geodynamics》 2025年第5期617-623,共7页
In the variance component estimation(VCE)of geodetic data,the problem of negative VCE is likely to occur.In the ordinary additive error model,there have been related studies to solve the problem of negative variance c... In the variance component estimation(VCE)of geodetic data,the problem of negative VCE is likely to occur.In the ordinary additive error model,there have been related studies to solve the problem of negative variance components.However,there is still no related research in the mixed additive and multiplicative random error model(MAMREM).Based on the MAMREM,this paper applies the nonnegative least squares variance component estimation(NNLS-VCE)algorithm to this model.The correlation formula and iterative algorithm of NNLS-VCE for MAMREM are derived.The problem of negative variance in VCE for MAMREM is solved.This paper uses the digital simulation example and the Digital Terrain Mode(DTM)to prove the proposed algorithm's validity.The experimental results demonstrated that the proposed algorithm can effectively correct the VCE in MAMREM when there is a negative VCE. 展开更多
关键词 Mixed additive and multiplicative random error model Stochastic model Non-negative least squares variance component estimation
原文传递
基于基站筛选和K-Means融合的UWB室内定位算法
13
作者 高培 蒋学程 何栋炜 《闽江学院学报》 2025年第5期20-30,共11页
针对超宽带(UWB)定位精度受多径效应和非视距(NLOS)等因素影响的问题,分析了HDS-TWR方法的测距误差特征,提出了一种基于基站筛选和K-Means融合的UWB室内定位算法。首先,引入拉依达准则对测距数据中的异常值或缺失值进行处理,其次,设计... 针对超宽带(UWB)定位精度受多径效应和非视距(NLOS)等因素影响的问题,分析了HDS-TWR方法的测距误差特征,提出了一种基于基站筛选和K-Means融合的UWB室内定位算法。首先,引入拉依达准则对测距数据中的异常值或缺失值进行处理,其次,设计了基站筛选和最小二乘法相结合的标签初始定位算法,最后,基于K-Means聚类算法确定k个可信度高的参考位置及聚类点密度,进而利用基于密度的加权质心算法求出标签的最优位置。实验结果表明,对比Chan算法和LSM-Kalman算法和Chan-KMeans算法等,该算法定位精度分别提高了48.86%、23.29%和41.60%。 展开更多
关键词 超宽带 三维定位 最小二乘法 K-meanS算法 基站筛选
在线阅读 下载PDF
GNSS测量精度的全站仪验证方法研究
14
作者 尹业彪 兰世雄 +1 位作者 孙建邦 杨振胤 《西北水电》 2026年第1期1-4,共4页
基于全站仪的GNSS测量成果精度验证方法,面临着缺乏系统理论支持、评价标准不统一及指标混乱等问题。为解决这些问题,基于误差传播律,提出了一种新的验证方法,利用观测数据中的真误差来推导中误差,并据此明确回应相关规范对边长相对精... 基于全站仪的GNSS测量成果精度验证方法,面临着缺乏系统理论支持、评价标准不统一及指标混乱等问题。为解决这些问题,基于误差传播律,提出了一种新的验证方法,利用观测数据中的真误差来推导中误差,并据此明确回应相关规范对边长相对精度和测角精度的具体要求。结果表明:该方法不仅从理论上为全站仪验证GNSS测量成果精度提供了科学的计算模型,而且具备较强的实践可行性,此方法适用于不同等级GNSS控制网成果的精度验证,有助于提升GNSS测量成果精度验证的准确性和全面性。 展开更多
关键词 控制测量 GNSS 边长相对中误差 测角中误差 质量评价
在线阅读 下载PDF
基于混合模式的电力机车直驱永磁同步电机无感控制研究
15
作者 马志军 张志锋 +1 位作者 王乃福 黄凯 《电机与控制学报》 北大核心 2026年第1期128-136,共9页
为了提高电力机车永磁牵引系统的可靠性,降低控制系统成本,设计一种基于混合模式的永磁电机无位置传感器控制系统。低速区向系统注入频率为开关频率的方波高频电压,提取高频电流后,利用注入高频电压时电机等效为感性负载的特性,设计鲁... 为了提高电力机车永磁牵引系统的可靠性,降低控制系统成本,设计一种基于混合模式的永磁电机无位置传感器控制系统。低速区向系统注入频率为开关频率的方波高频电压,提取高频电流后,利用注入高频电压时电机等效为感性负载的特性,设计鲁棒观测器估计电机转子位置,实现低速满转矩发挥。中高速区在d、q轴建立永磁电机扩展反电势模型,设计高精度龙贝格观测器观测反电势,经过鲁棒观测器调节后估计电机转子位置。使用同一个位置鲁棒观测器,设计切换策略保障算法切换过程平滑过渡,实现低载波比无感控制。以一台直驱永磁同步电机作为控制对象,在永磁直驱牵引系统电机对拖平台进行试验。试验结果表明,所设计的控制算法可实现直驱电机全速范围无感控制高性能运行,高速区位置估计误差在4度以内。 展开更多
关键词 电力机车 直驱永磁同步电机 转子位置估计 方波电压注入 龙贝格观测器 位置误差
在线阅读 下载PDF
LTE系统中的Mean-OTDOA定位算法 被引量:7
16
作者 陈亚军 彭建华 +1 位作者 黄开枝 罗文宇 《计算机应用研究》 CSCD 北大核心 2014年第6期1783-1786,共4页
由于LTE蜂窝网中远近效应的影响,终端测量到的邻近基站信号的定位参数会存在较大的偏差,导致OTDOA定位方法(到达时间差定位法)估计的终端位置存在较大误差。基于此,提出一种改进的Mean-OTDOA定位算法。首先估计终端与各基站的时延,然后... 由于LTE蜂窝网中远近效应的影响,终端测量到的邻近基站信号的定位参数会存在较大的偏差,导致OTDOA定位方法(到达时间差定位法)估计的终端位置存在较大误差。基于此,提出一种改进的Mean-OTDOA定位算法。首先估计终端与各基站的时延,然后对终端与多基站的距离测量值进行平均,作为OTDOA定位方法中的参考距离,最后利用泰勒级数展开法对终端位置进行估计。仿真结果表明,该算法可提高终端的定位精度,在基站数目为5、测量误差标准差为50 m时,本算法的均方根误差比OTDOA算法降低了5.2039 m,且随着基站数目的增加,定位精度的改善程度优于OTDOA算法。 展开更多
关键词 LTE系统 远近效应 mean-OTDOA定位算法 泰勒级数 均方根误差
在线阅读 下载PDF
基于Fisher线性判别率的加权K-means聚类算法 被引量:5
17
作者 杨鹤标 薛艳锋 +2 位作者 冯进兰 沈项军 吴静丽 《计算机应用研究》 CSCD 北大核心 2010年第12期4439-4442,共4页
为提高K-means聚类效果,采用Fisher线性判别率的方法确定特征在聚类中的贡献度并依此对特征进行加权聚类。在人工和实际数据集上所做的实验表明,本方法在聚类效果上优于其他同类加权K-means聚类算法。
关键词 K-均值 聚类 Fisher线性判别率 特征加权 调整随机指标 类内错误率均方和
在线阅读 下载PDF
一种基于熵和均方差法综合赋权的K-means算法 被引量:11
18
作者 上官廷华 冯荣耀 柳宏川 《计算机与现代化》 2010年第4期34-36,共3页
在传统的K-means聚类算法基础上,本文提出一种基于熵和均方差法综合赋权的Syn-K-means算法。引入综合权重提高聚类结果的类内相似度,从而提高聚类精度。算法中特征权重的计算基于概率论中数字特征的基本描述方法——均方差和信息论中信... 在传统的K-means聚类算法基础上,本文提出一种基于熵和均方差法综合赋权的Syn-K-means算法。引入综合权重提高聚类结果的类内相似度,从而提高聚类精度。算法中特征权重的计算基于概率论中数字特征的基本描述方法——均方差和信息论中信息特征的基本度量方法——熵;综合赋权系数的选择采用主观设定法求解。实验结果表明,Syn-K-means算法在聚类精度方面优于标准的K-means算法。 展开更多
关键词 K-均值算法 综合权重 均方差
在线阅读 下载PDF
改进k-means聚类算法多模型建模的一种新的评价函数 被引量:6
19
作者 周立芳 周芦文 赵豫红 《化工学报》 EI CAS CSCD 北大核心 2007年第8期2051-2055,共5页
The modeling and control of pH neutralization processes is a difficult problem in the field of process control.A multi-modeling method using an improved k-means clustering based on a new validity function is proposed ... The modeling and control of pH neutralization processes is a difficult problem in the field of process control.A multi-modeling method using an improved k-means clustering based on a new validity function is proposed in this paper.There are some common problems, including the number of clusters assumed as a priori knowledge and initial cluster centers selected randomly for classical k-means clustering.The proposed algorithm is used to compute initial cluster centers and a new validity function is added to determine the appropriate number of clusters, then partial least squares (PLS) is used to construct the regression equation for each local cluster.Simulation results showed that multiple models using the proposed algorithm gave good performance, and the feasibility and validity of the proposed algorithm was verified. 展开更多
关键词 K-meanS聚类 性能评价函数 PH中和过程 偏最小二乘算法
在线阅读 下载PDF
基于改进的Mean Shift鲁棒跟踪算法 被引量:4
20
作者 徐海明 黄山 李云彤 《计算机工程与科学》 CSCD 北大核心 2015年第6期1161-1167,共7页
Mean Shift跟踪算法在目标尺度变化大和被遮挡时存在较大的缺陷。针对这一问题,提出了一种基于多级正方形匹配的自适应带宽选择和分块抗遮挡的目标跟踪算法。该算法采用目标中心点的离散程度和增量试探法计算出可能的变化尺度,然后采用... Mean Shift跟踪算法在目标尺度变化大和被遮挡时存在较大的缺陷。针对这一问题,提出了一种基于多级正方形匹配的自适应带宽选择和分块抗遮挡的目标跟踪算法。该算法采用目标中心点的离散程度和增量试探法计算出可能的变化尺度,然后采用多级正方形匹配法预测目标的运动趋势,将巴氏系数最大者的尺度作为Mean Shift核函数新的带宽。同时,对前景目标进行分块,根据子块的遮挡程度自适应改变子块权重并按一定准则融合有效子块的跟踪结果。实验结果表明,该算法具有很好的鲁棒性。 展开更多
关键词 mean SHIFT 目标跟踪 多级正方形匹配 分块
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部