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不平衡集成算法LASSO-EasyEnsemble在冠心病预后预测中的应用及可解释性研究
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作者 昝家昕 杨弘 +4 位作者 田晶 闫晶晶 和紫铉 杜宇涛 张岩波 《中国卫生统计》 北大核心 2025年第2期197-203,共7页
目的 针对冠心病预后预测中遇到的高噪声、类间不平衡的特点,通过LASSO特征筛选后,构建EasyEnsemble不平衡集成模型并对模型性能进行评估。方法 基于2009—2018年美国健康与营养调查公共数据库的调查数据,随访时间截止到2019年。预后有... 目的 针对冠心病预后预测中遇到的高噪声、类间不平衡的特点,通过LASSO特征筛选后,构建EasyEnsemble不平衡集成模型并对模型性能进行评估。方法 基于2009—2018年美国健康与营养调查公共数据库的调查数据,随访时间截止到2019年。预后有无因病死亡作为结局,通过LASSO进行特征选择,使用筛选后特征构建EasyEnsemble不平衡集成预测模型和SMOTE+LightGBM、XGBoost、Random Forest预测模型,采用网格搜索法对每个模型进行参数优化,通过AUC、精确率、特异度、G-mean和性能曲线评价其分类性能;应用SHAP(shapley additive explanation)进行模型可解释性分析。结果 EasyEnsemble模型的综合性能最高,AUC为0.80(95%CI:0.79~0.82),精确率为0.86(95%CI:0.78~0.93),特异度为0.99(95%CI:0.98~0.99)和G-mean为0.79(95%CI:0.76~0.83),性能曲线也显示最高。同时,年龄、血清磷、糖尿病、白蛋白等是影响患者预后的重要因素。结论 基于LASSO-EasyEnsemble的不平衡集成模型能够实现对冠心病患者预后的精准预测,结合SHAP可以帮助临床医生更好地评估疾病严重程度和识别高危人群以便实现患者个性化管理。 展开更多
关键词 冠心病 不平衡数据 集成学习 预后预测 可解释性
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短期负荷预测的Ensemble混沌预测方法 被引量:14
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作者 杨正瓴 王渭巍 +2 位作者 曹东波 张军 陈曦 《电力系统自动化》 EI CSCD 北大核心 2007年第23期34-37,共4页
负荷记录中的噪声以及预测方法中矩阵数值计算的奇异性,使得一次预测得到的结果具有较大的误差。为了降低初值中噪声的不利影响,将数值天气预报中的Ensemble方法移植到短期负荷预测中。在混沌相空间重构预测中,在参考矢量上叠加一定强... 负荷记录中的噪声以及预测方法中矩阵数值计算的奇异性,使得一次预测得到的结果具有较大的误差。为了降低初值中噪声的不利影响,将数值天气预报中的Ensemble方法移植到短期负荷预测中。在混沌相空间重构预测中,在参考矢量上叠加一定强度的正态分布噪声,形成多个扰动后的参考矢量,分别预测后得到多个预测结果,再由这些预测结果合成概率化的预测结果。采用这种Ensemble技术,不仅可以提高预测准确率,还可以得到概率化的预测结果。 展开更多
关键词 短期负荷预测 混沌 ensemble 概率化
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医疗异构环境下Ensemble平台数据资源交互的研究 被引量:6
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作者 蒙华 李东林 +1 位作者 韦润莲 翟玉兰 《计算机应用与软件》 CSCD 2016年第10期114-117,152,共5页
随着区域医疗发展的推进,医疗信息资源集成是关键,这就要求系统开发考虑到当前医疗异构环境下信息系统的集成和数据中心的建立。由于医疗信息资源形式各异,系统软件数据库不同,以及大数据量交换、对业务流程的控制要求等,阻碍了信息系... 随着区域医疗发展的推进,医疗信息资源集成是关键,这就要求系统开发考虑到当前医疗异构环境下信息系统的集成和数据中心的建立。由于医疗信息资源形式各异,系统软件数据库不同,以及大数据量交换、对业务流程的控制要求等,阻碍了信息系统集成和资源共享,提出基于Ensemble集成平台(内置后关系型数据库Caché),避开限制条件,实现医疗资源数据交互的方法。从广西医科大学第一附属医院满意度回访的需求出发,阐述交换数据定义、消息流程以及传输机制等环节,通过在Ensemble建立Business Service、Business Process、Business Operation实现接口平台消息发送和结果返回过程。在实践运用中表明,Ensemble集成平台能满足医疗异构环境下数据交换要求,促进医院信息化建设。 展开更多
关键词 系统集成 ensemble Cachie 接口技术 满意度回访
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基于Ensemble的增量分类方法 被引量:1
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作者 刘波 潘久辉 《计算机工程》 CAS CSCD 北大核心 2008年第19期187-188,191,共3页
针对在维护数据挖掘模型过程中须反复计算数据集、效率较低的问题,基于Ensembles学习思想,研究增量数据集的弱分类器生成方法,根据增量数据集分类器之间的相异度提出新的组合分类算法,分析组合分类器的出错率。实验结果表明,该分类方法... 针对在维护数据挖掘模型过程中须反复计算数据集、效率较低的问题,基于Ensembles学习思想,研究增量数据集的弱分类器生成方法,根据增量数据集分类器之间的相异度提出新的组合分类算法,分析组合分类器的出错率。实验结果表明,该分类方法是有效的。 展开更多
关键词 增量 分类 ensemble学习 组合
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Ensemble-SISPLS近红外光谱变量选择方法 被引量:1
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作者 李四海 赵磊 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2019年第4期1047-1052,共6页
近红外光谱具有高维小样本的特点,变量选择是提高定量分析模型稳健性和可解释性的一种有效方法。确定独立筛选(SIS)是一种基于边际相关性的超高维数据变量选择方法,广泛用于基因微阵列数据的变量选择。SIS具有将数据维度降低至样本大小... 近红外光谱具有高维小样本的特点,变量选择是提高定量分析模型稳健性和可解释性的一种有效方法。确定独立筛选(SIS)是一种基于边际相关性的超高维数据变量选择方法,广泛用于基因微阵列数据的变量选择。SIS具有将数据维度降低至样本大小规模的能力,其降维能力与LASSO相当,在相当宽泛的近似条件下,由于具有安全筛选性质,所有重要变量被保留的概率趋于1。基于确定独立筛选偏最小二乘(SIS-SPLS)的变量选择是一种迭代式的SIS变量选择方法,首先利用SIS方法完成光谱重要变量的初选;然后根据重要变量的边际相关性大小进行逐步前向选择:建立偏最小二乘回归模型,依据贝叶斯信息准则(BIC)确定最终的变量选择结果。SIS-SPLS以逐步前向选择的方式实现对重要变量的增量式筛选,随着潜变量个数的增加及因变量残差的逐步减小, SIS-SPLS方法选择的变量个数将趋于稳定。然而仅以边际相关性对变量重要性进行评价,当光谱变量个数远大于样本数时,该方法也存在选择的变量过多、变量选择结果不够稳健等问题。为进一步提高小样本情况下变量选择的稳健性,将集成学习引入SIS-SPLS方法之中,提出了一种集成SIS-SPLS变量选择方法(Ensemble-SISPLS)。该方法首先对校正集样本进行自助重采样,对采样得到的每一个校正子集分别使用SIS-SPLS方法进行变量筛选,通过投票机制并设置频次阈值对所有校正子集的变量选择结果进行集成,选择出现频次大于给定阈值的变量并建立偏最小二乘回归模型,计算5折交叉验证均方根误差。对频次阈值和潜变量个数两个关键参数使用网格搜索法进行优选,根据子模型的交叉验证均方根误差和变量个数对子模型性能进行综合评价,以最优子模型包含的变量作为最终的变量选择结果。分别在Corn数据集和当归数据集上进行变量选择实验,比较Ensemble-SISPLS, SIS-SPLS和UVE-PLS三种变量选择方法的性能。其中当归数据集共77个样本,样本采自甘肃岷县和渭源县,使用Nicolet-6700型近红外光谱仪扫描得到所有样本的近红外光谱并对当归中的阿魏酸含量进行预测。Ensemble-SISPLS方法在Corn数据集上选择的变量个数、 RMSEP和决定系数分别为22, 0.000 8和0.999 8; SIS-SPLS方法在Corn数据集上选择的变量个数、 RMSEP和决定系数分别为97, 0.007 3和0.998 8。Ensemble-SISPLS方法在当归数据集上选择的变量个数、 RMSEP和决定系数分别为24, 0.018 1和0.996 3; SIS-SPLS方法在当归数据集上选择的变量个数、 RMSEP和决定系数分别为38, 0.022 6和0.994 3。结果表明,该方法进一步提高了变量选择结果的稳健性和预测能力。Ensemble-SISPLS变量选择方法有效结合了SIS-SPLS较强的变量选择能力和集成学习良好的泛化能力,提高了变量选择的稳健性。此外,由于在子模型的预测能力和变量个数之间进行了折中,一定程度上减少了选择变量的个数,提高了模型的可解释性。 展开更多
关键词 近红外光谱 变量选择 确定独立筛选 偏最小二乘 集成学习
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Novel algorithm for constructing support vector machine regression ensemble 被引量:6
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作者 Li Bo Li Xinjun Zhao Zhiyan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第3期541-545,共5页
A novel algorithm for constructing support vector machine regression ensemble is proposed. As to regression prediction, support vector machine regression (SVMR) ensemble is proposed by resampling from given training... A novel algorithm for constructing support vector machine regression ensemble is proposed. As to regression prediction, support vector machine regression (SVMR) ensemble is proposed by resampling from given training data sets repeatedly and aggregating several independent SVMRs, each of which is trained to use a replicated training set. After training, several independently trained SVMRs need to be aggregated in an appropriate combination manner. Generally, the linear weighting is usually used like expert weighting score in Boosting Regression and it is without optimization capacity. Three combination techniques are proposed, including simple arithmetic mean, linear least square error weighting and nonlinear hierarchical combining that uses another upper-layer SVMR to combine several lower-layer SVMRs. Finally, simulation experiments demonstrate the accuracy and validity of the presented algorithm. 展开更多
关键词 SVMR ensemble boosting regression combination optimization strategy.
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Rockburst prediction in hard rock mines developing bagging and boosting tree-based ensemble techniques 被引量:30
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作者 WANG Shi-ming ZHOU Jian +3 位作者 LI Chuan-qi Danial Jahed ARMAGHANI LI Xi-bing Hani SMITRI 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第2期527-542,共16页
Rockburst prediction is of vital significance to the design and construction of underground hard rock mines.A rockburst database consisting of 102 case histories,i.e.,1998−2011 period data from 14 hard rock mines was ... Rockburst prediction is of vital significance to the design and construction of underground hard rock mines.A rockburst database consisting of 102 case histories,i.e.,1998−2011 period data from 14 hard rock mines was examined for rockburst prediction in burst-prone mines by three tree-based ensemble methods.The dataset was examined with six widely accepted indices which are:the maximum tangential stress around the excavation boundary(MTS),uniaxial compressive strength(UCS)and uniaxial tensile strength(UTS)of the intact rock,stress concentration factor(SCF),rock brittleness index(BI),and strain energy storage index(EEI).Two boosting(AdaBoost.M1,SAMME)and bagging algorithms with classification trees as baseline classifier on ability to learn rockburst were evaluated.The available dataset was randomly divided into training set(2/3 of whole datasets)and testing set(the remaining datasets).Repeated 10-fold cross validation(CV)was applied as the validation method for tuning the hyper-parameters.The margin analysis and the variable relative importance were employed to analyze some characteristics of the ensembles.According to 10-fold CV,the accuracy analysis of rockburst dataset demonstrated that the best prediction method for the potential of rockburst is bagging when compared to AdaBoost.M1,SAMME algorithms and empirical criteria methods. 展开更多
关键词 ROCKBURST hard rock PREDICTION BAGGING BOOSTING ensemble learning
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基于改进Self-paced Ensemble算法的浏览器指纹识别
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作者 张德升 陈博 +3 位作者 张建辉 卜佑军 孙重鑫 孙嘉 《计算机科学》 CSCD 北大核心 2023年第7期317-324,共8页
浏览器指纹技术凭借其无状态、跨域一致等优点,已经被许多网站应用到用户追踪、广告投放和安全验证等方面。浏览器指纹识别的过程是典型的不平衡数据的分类过程。针对当前浏览器指纹长期追踪过程中存在数据样本类不平衡导致指纹识别准... 浏览器指纹技术凭借其无状态、跨域一致等优点,已经被许多网站应用到用户追踪、广告投放和安全验证等方面。浏览器指纹识别的过程是典型的不平衡数据的分类过程。针对当前浏览器指纹长期追踪过程中存在数据样本类不平衡导致指纹识别准确度低、长期追踪易失效等问题,提出了改进的Self-paced Ensemble(Improved SPE,ISPE)方法应用于浏览器指纹识别。对浏览器指纹样本欠采样过程和集成学习单个分类器的训练过程进行了改进,重点针对难以识别的浏览器指纹,添加类注意力机制并优化自协调因子,使分类器在训练和识别浏览器指纹的过程中更加注重边界样本的分类效果,从而提升总体的浏览器指纹识别准确度。在所收集的3 483条指纹和开源数据集中的15 000条指纹上进行了实验,结果表明,ISPE算法在浏览器指纹匹配识别的F1-score达到95.6%,相比Bi-RNN算法提高了16.8%。 展开更多
关键词 浏览器指纹 用户追踪 Self-paced ensemble 欠采样 集成学习
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An enhanced hybrid ensemble deep learning approach for forecasting daily PM_(2.5) 被引量:7
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作者 LIU Hui DENG Da-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第6期2074-2083,共10页
PM_(2.5) forecasting technology can provide a scientific and effective way to assist environmental governance and protect public health.To forecast PM_(2.5),an enhanced hybrid ensemble deep learning model is proposed ... PM_(2.5) forecasting technology can provide a scientific and effective way to assist environmental governance and protect public health.To forecast PM_(2.5),an enhanced hybrid ensemble deep learning model is proposed in this research.The whole framework of the proposed model can be generalized as follows:the original PM_(2.5) series is decomposed into 8 sub-series with different frequency characteristics by variational mode decomposition(VMD);the long short-term memory(LSTM)network,echo state network(ESN),and temporal convolutional network(TCN)are applied for parallel forecasting for 8 different frequency PM_(2.5) sub-series;the gradient boosting decision tree(GBDT)is applied to assemble and reconstruct the forecasting results of LSTM,ESN and TCN.By comparing the forecasting data of the models over 3 PM_(2.5) series collected from Shenyang,Changsha and Shenzhen,the conclusions can be drawn that GBDT is a more effective method to integrate the forecasting result than traditional heuristic algorithms;MAE values of the proposed model on 3 PM_(2.5) series are 1.587,1.718 and 1.327μg/m3,respectively and the proposed model achieves more accurate results for all experiments than sixteen alternative forecasting models which contain three state-of-the-art models. 展开更多
关键词 PM_(2.5)forecasting variational mode decomposition deep neural network ensemble learning
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Ensemble feature selection integrating elitist roles and quantum game model 被引量:1
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作者 Weiping Ding Jiandong Wang +1 位作者 Zhijin Guan Quan Shi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第3期584-594,共11页
To accelerate the selection process of feature subsets in the rough set theory (RST), an ensemble elitist roles based quantum game (EERQG) algorithm is proposed for feature selec- tion. Firstly, the multilevel eli... To accelerate the selection process of feature subsets in the rough set theory (RST), an ensemble elitist roles based quantum game (EERQG) algorithm is proposed for feature selec- tion. Firstly, the multilevel elitist roles based dynamics equilibrium strategy is established, and both immigration and emigration of elitists are able to be self-adaptive to balance between exploration and exploitation for feature selection. Secondly, the utility matrix of trust margins is introduced to the model of multilevel elitist roles to enhance various elitist roles' performance of searching the optimal feature subsets, and the win-win utility solutions for feature selec- tion can be attained. Meanwhile, a novel ensemble quantum game strategy is designed as an intriguing exhibiting structure to perfect the dynamics equilibrium of multilevel elitist roles. Finally, the en- semble manner of multilevel elitist roles is employed to achieve the global minimal feature subset, which will greatly improve the fea- sibility and effectiveness. Experiment results show the proposed EERQG algorithm has superiority compared to the existing feature selection algorithms. 展开更多
关键词 ensemble quantum game utility matrix of trust mar-gin dynamics equilibrium strategy multilevel elitist role feature selection and classification.
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Air combat target maneuver trajectory prediction based on robust regularized Volterra series and adaptive ensemble online transfer learning 被引量:2
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作者 Xi Zhi-fei Kou Ying-xin +4 位作者 Li Zhan-wu Lv Yue Xu An Li You Li Shuang-qing 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第2期187-206,共20页
Target maneuver trajectory prediction is an important prerequisite for air combat situation awareness and maneuver decision-making.However,how to use a large amount of trajectory data generated by air combat confronta... Target maneuver trajectory prediction is an important prerequisite for air combat situation awareness and maneuver decision-making.However,how to use a large amount of trajectory data generated by air combat confrontation training to achieve real-time and accurate prediction of target maneuver trajectory is an urgent problem to be solved.To solve this problem,in this paper,a hybrid algorithm based on transfer learning,online learning,ensemble learning,regularization technology,target maneuvering segmentation point recognition algorithm,and Volterra series,abbreviated as AERTrOS-Volterra is proposed.Firstly,the model makes full use of a large number of trajectory sample data generated by air combat confrontation training,and constructs a Tr-Volterra algorithm framework suitable for air combat target maneuver trajectory prediction,which realizes the extraction of effective information from the historical trajectory data.Secondly,in order to improve the real-time online prediction accuracy and robustness of the prediction model in complex electromagnetic environments,on the basis of the TrVolterra algorithm framework,a robust regularized online Sequential Volterra prediction model is proposed by integrating online learning method,regularization technology and inverse weighting calculation method based on the priori error.Finally,inspired by the preferable performance of models ensemble,ensemble learning scheme is also incorporated into our proposed algorithm,which adaptively updates the ensemble prediction model according to the performance of the model on real-time samples and the recognition results of target maneuvering segmentation points,including the adaptation of model weights;adaptation of parameters;and dynamic inclusion and removal of models.Compared with many existing time series prediction methods,the newly proposed target maneuver trajectory prediction algorithm can fully mine the prior knowledge contained in the historical data to assist the current prediction.The rationality and effectiveness of the proposed algorithm are verified by simulation on three sets of chaotic time series data sets and a set of real target maneuver trajectory data sets. 展开更多
关键词 Maneuver trajectory prediction Volterra series Transfer learning Online learning ensemble learning Robust regularization
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Multi Boost with ENN-based ensemble fault diagnosis method and its application in complicated chemical process 被引量:1
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作者 夏崇坤 苏成利 +1 位作者 曹江涛 李平 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1183-1197,共15页
Fault diagnosis plays an important role in complicated industrial process.It is a challenging task to detect,identify and locate faults quickly and accurately for large-scale process system.To solve the problem,a nove... Fault diagnosis plays an important role in complicated industrial process.It is a challenging task to detect,identify and locate faults quickly and accurately for large-scale process system.To solve the problem,a novel Multi Boost-based integrated ENN(extension neural network) fault diagnosis method is proposed.Fault data of complicated chemical process have some difficult-to-handle characteristics,such as high-dimension,non-linear and non-Gaussian distribution,so we use margin discriminant projection(MDP) algorithm to reduce dimensions and extract main features.Then,the affinity propagation(AP) clustering method is used to select core data and boundary data as training samples to reduce memory consumption and shorten learning time.Afterwards,an integrated ENN classifier based on Multi Boost strategy is constructed to identify fault types.The artificial data sets are tested to verify the effectiveness of the proposed method and make a detailed sensitivity analysis for the key parameters.Finally,a real industrial system—Tennessee Eastman(TE) process is employed to evaluate the performance of the proposed method.And the results show that the proposed method is efficient and capable to diagnose various types of faults in complicated chemical process. 展开更多
关键词 extension neural network multi-classifier ensembles margin discriminant projection affinity propagation FAULTDIAGNOSIS TE process
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基于组合物种分布模型(Ensemble Model)的厚朴适宜生境分布模拟 被引量:15
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作者 朱妮 《四川农业大学学报》 CSCD 北大核心 2019年第4期481-489,共9页
【目的】建立组合物种分布模型,模拟厚朴在我国南方的分布格局,探讨影响其生长环境因子的阈值,为厚朴的人工种植,野生资源保护等提供理论依据。【方法】基于公开发表的文献中精确的厚朴分布数据与23个环境因子变量,利用BIOMOD2建模平台... 【目的】建立组合物种分布模型,模拟厚朴在我国南方的分布格局,探讨影响其生长环境因子的阈值,为厚朴的人工种植,野生资源保护等提供理论依据。【方法】基于公开发表的文献中精确的厚朴分布数据与23个环境因子变量,利用BIOMOD2建模平台中的9个模型算法构建组合物种分布模型模拟厚朴的适宜生境分布。【结果】①厚朴在我国南方适宜生境面积为0.53×10^6 km^2,主要分布在四川东部、陕西南部、重庆东部、湖北西部、贵州、福建、江西、湖南等地区。②在组成组合物种分布模型的9个单模型算法中,推进式回归树模型(GBM)和随机森林(RF)的模拟效果最好,表面分室模型(SRE)与分类树分析模型(CTA)结果较差。组合物种分布模型的TSS为0.905,ROC值为0.975,说明组合模型能够在一定程度上提高模型的精度。【结论】厚朴在我国南方分布较为广泛,但是考虑植被类型限制时,其生境较为破碎,应该在其适宜生境区域加强物种保护。 展开更多
关键词 厚朴 物种分布模型 BIOMOD2 组合物种分布模型
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Novel ensemble learning based on multiple section distribution in distributed environment
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作者 Fang Min 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第2期377-380,共4页
Because most ensemble learning algorithms use the centralized model, and the training instances must be centralized on a single station, it is difficult to centralize the training data on a station. A distributed ense... Because most ensemble learning algorithms use the centralized model, and the training instances must be centralized on a single station, it is difficult to centralize the training data on a station. A distributed ensemble learning algorithm is proposed which has two kinds of weight genes of instances that denote the global distribution and the local distribution. Instead of the repeated sampling method in the standard ensemble learning, non-balance sampling from each station is used to train the base classifier set of each station. The concept of the effective nearby region for local integration classifier is proposed, and is used for the dynamic integration method of multiple classifiers in distributed environment. The experiments show that the ensemble learning algorithm in distributed environment proposed could reduce the time of training the base classifiers effectively, and ensure the classify performance is as same as the centralized learning method. 展开更多
关键词 distributed environment ensemble learning multiple classifiers combination.
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A novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise,minimum mean square variance criterion and least mean square adaptive filter 被引量:9
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作者 Yu-xing Li Long Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第3期543-554,共12页
Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity ... Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity of marine environment and the particularity of underwater acoustic channel,noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing.In order to solve the dilemma,we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN),minimum mean square variance criterion(MMSVC) and least mean square adaptive filter(LMSAF).This noise reduction technique,named CEEMDAN-MMSVC-LMSAF,has three main advantages:(i) as an improved algorithm of empirical mode decomposition(EMD) and ensemble EMD(EEMD),CEEMDAN can better suppress mode mixing,and can avoid selecting the number of decomposition in variational mode decomposition(VMD);(ii) MMSVC can identify noisy intrinsic mode function(IMF),and can avoid selecting thresholds of different permutation entropies;(iii) for noise reduction of noisy IMFs,LMSAF overcomes the selection of deco mposition number and basis function for wavelet noise reduction.Firstly,CEEMDAN decomposes the original signal into IMFs,which can be divided into noisy IMFs and real IMFs.Then,MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs.Finally,both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained.Compared with other noise reduction techniques,the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals,which has the better noise reduction effect and has practical application value.CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection,feature extraction,classification and recognition of underwater acoustic signals. 展开更多
关键词 Underwater acoustic signal Noise reduction Empirical mode decomposition(EMD) ensemble EMD(EEMD) Complete EEMD with adaptive noise(CEEMDAN) Minimum mean square variance criterion(MMSVC) Least mean square adaptive filter(LMSAF) Ship-radiated noise
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Phase Space View of Ensembles of Excited States
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作者 NAGY Agnes 《物理化学学报》 SCIE CAS CSCD 北大核心 2018年第5期492-496,共5页
The density functional theory and its extension to ensembles of excited states can be formalized as thermodynamics. However, these theories are not unique because one of their key quantities, the kinetic energy densit... The density functional theory and its extension to ensembles of excited states can be formalized as thermodynamics. However, these theories are not unique because one of their key quantities, the kinetic energy density,can be defined in several ways. Usually, the everywhere positive gradient form is applied; however, other forms are also acceptable, provided they integrate to the true kinetic energy. Recently, a kinetic energy density of the ground-state theory maximizing the information entropy has been proposed. Here, ensemble kinetic energy density, leading to extremum information entropy, is derived via constrained search. The corresponding ensemble temperature is found to be constant. 展开更多
关键词 热力学 温度 动能 密度
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State estimation of connected vehicles using a nonlinear ensemble filter
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作者 刘江 陈华展 +1 位作者 蔡伯根 王剑 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2406-2415,共10页
The concept of connected vehicles is with great potentials for enhancing the road transportation systems in the future. To support the functions and applications under the connected vehicles frame, the estimation of d... The concept of connected vehicles is with great potentials for enhancing the road transportation systems in the future. To support the functions and applications under the connected vehicles frame, the estimation of dynamic states of the vehicles under the cooperative environments is a fundamental issue. By integrating multiple sensors, localization modules in OBUs(on-board units) require effective estimation solutions to cope with various operation conditions. Based on the filtering estimation framework for sensor fusion, an ensemble Kalman filter(En KF) is introduced to estimate the vehicle's state with observations from navigation satellites and neighborhood vehicles, and the original En KF solution is improved by using the cubature transformation to fulfill the requirements of the nonlinearity approximation capability, where the conventional ensemble analysis operation in En KF is modified to enhance the estimation performance without increasing the computational burden significantly. Simulation results from a nonlinear case and the cooperative vehicle localization scenario illustrate the capability of the proposed filter, which is crucial to realize the active safety of connected vehicles in future intelligent transportation. 展开更多
关键词 connected vehicles state estimation cooperative positioning nonlinear ensemble filter global navigation satellite system (GNSS) dedicated short range communication (DSRC)
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An Improved Particle Swarm Optimization Algorithm Based on Ensemble Technique
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作者 施彦 黄聪明 《Defence Technology(防务技术)》 SCIE EI CAS 2006年第4期310-314,共5页
An improved particle swarm optimization (PSO) algorithm based on ensemble technique is presented. The algorithm combines some previous best positions (pbest) of the particles to get an ensemble position (Epbest), whic... An improved particle swarm optimization (PSO) algorithm based on ensemble technique is presented. The algorithm combines some previous best positions (pbest) of the particles to get an ensemble position (Epbest), which is used to replace the global best position (gbest). It is compared with the standard PSO algorithm invented by Kennedy and Eberhart and some improved PSO algorithms based on three different benchmark functions. The simulation results show that the improved PSO based on ensemble technique can get better solutions than the standard PSO and some other improved algorithms under all test cases. 展开更多
关键词 机器学习 进化计算 粒子群优化算法 系综技术
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一种适用于风储微电网的混合储能系统的功率分配策略 被引量:2
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作者 李艳波 杨凯 +3 位作者 陈俊硕 姚博彬 刘维宇 武奇生 《电测与仪表》 北大核心 2025年第2期43-50,共8页
混合储能系统是微电网的重要组成部分之一,研究其功率分配策略对电池的保护具有重要意义。在由超级电容-蓄电池组成的混合储能系统的基础上,提出互补集合经验模态分解的方法来平抑风力发电不稳定性而引起的功率波动。针对风力发电的波... 混合储能系统是微电网的重要组成部分之一,研究其功率分配策略对电池的保护具有重要意义。在由超级电容-蓄电池组成的混合储能系统的基础上,提出互补集合经验模态分解的方法来平抑风力发电不稳定性而引起的功率波动。针对风力发电的波动性及不确定性,互补集合经验模态分解法能够把风电原始能量信号分解为固有模态分量和余量,通过能量熵理论求出功率一次分配分界点,即初始功率分配;提出利用模糊控制对混合储能系统的荷电状态进行优化约束,自适应调整并修正混合储能系统功率分配指令。利用MATLAB程序及Simulink仿真模型并结合算例分析,结果说明了提出的策略可以使蓄电池SOC波动不超过8%,超级电容SOC波动不超过10%,有效提高了整个系统的工作效率和使用寿命。 展开更多
关键词 互补集合经验模态分解法 模糊控制 荷电状态 能量熵
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基于Seq2Seq双向模型的水锤压力预测 被引量:1
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作者 吴罗长 刘振兴 +4 位作者 雷洁 颜建国 郭鹏程 孙帅辉 马晋阳 《振动与冲击》 北大核心 2025年第3期99-106,共8页
水锤计算对保障长距离输水工程管网系统安全稳定运行具有重要意义,但传统水锤数值方法存在模型复杂、计算量大的问题。为此,在自主开发的瞬态流试验平台上,通过支路快速关阀产生水锤,获取了不同流量和压力条件下的瞬态水锤压力。试验参... 水锤计算对保障长距离输水工程管网系统安全稳定运行具有重要意义,但传统水锤数值方法存在模型复杂、计算量大的问题。为此,在自主开发的瞬态流试验平台上,通过支路快速关阀产生水锤,获取了不同流量和压力条件下的瞬态水锤压力。试验参数范围为:体积流量15~55 m^(3)/h,压力150~450 kPa。采用集合经验模态分解方法对水锤信号进行滤波,并对水锤压力的变化规律进行了深入的研究分析。基于双向门控循环单元,建立了用于水锤压力预测的序列到序列(sequence-to-sequence,Seq2Seq)双向预测模型。结果表明,Seq2Seq双向预测模型能有效预测支路水锤,其预测数据决定系数在0.8以上,水锤特征参数预测准确率超过98%。该研究成果为水锤压力预测提供了一种新方法。 展开更多
关键词 水锤 瞬变流 Seq2Seq 经验模态分解
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