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An optimized cluster density matrix embedding theory
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作者 Hao Geng Quan-lin Jie 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第9期117-122,共6页
We propose an optimized cluster density matrix embedding theory(CDMET).It reduces the computational cost of CDMET with simpler bath states.And the result is as accurate as the original one.As a demonstration,we study ... We propose an optimized cluster density matrix embedding theory(CDMET).It reduces the computational cost of CDMET with simpler bath states.And the result is as accurate as the original one.As a demonstration,we study the distant correlations of the Heisenberg J_(1)-J_(2)model on the square lattice.We find that the intermediate phase(0.43≤sssim J_(2)≤sssim 0.62)is divided into two parts.One part is a near-critical region(0.43≤J_(2)≤0.50).The other part is the plaquette valence bond solid(PVB)state(0.51≤J_(2)≤0.62).The spin correlations decay exponentially as a function of distance in the PVB. 展开更多
关键词 cluster density matrix embedding theory distant correlation Heisenberg J_(1)-J_(2)model
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Similarity matrix-based K-means algorithm for text clustering 被引量:1
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作者 曹奇敏 郭巧 吴向华 《Journal of Beijing Institute of Technology》 EI CAS 2015年第4期566-572,共7页
K-means algorithm is one of the most widely used algorithms in the clustering analysis. To deal with the problem caused by the random selection of initial center points in the traditional al- gorithm, this paper propo... K-means algorithm is one of the most widely used algorithms in the clustering analysis. To deal with the problem caused by the random selection of initial center points in the traditional al- gorithm, this paper proposes an improved K-means algorithm based on the similarity matrix. The im- proved algorithm can effectively avoid the random selection of initial center points, therefore it can provide effective initial points for clustering process, and reduce the fluctuation of clustering results which are resulted from initial points selections, thus a better clustering quality can be obtained. The experimental results also show that the F-measure of the improved K-means algorithm has been greatly improved and the clustering results are more stable. 展开更多
关键词 text clustering K-means algorithm similarity matrix F-MEASURE
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Infrared spectroscopic probing of dimethylamine clusters in an Ar matrix
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作者 Siyang Li Henrik G.Kjaergaard Lin Du 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第2期51-59,共9页
Amines have many atmospheric sources and their clusters play an important role in aerosol nucleation processes. Clusters of a typical amine, dimethylamine(DMA), of different sizes were measured with matrix isolation... Amines have many atmospheric sources and their clusters play an important role in aerosol nucleation processes. Clusters of a typical amine, dimethylamine(DMA), of different sizes were measured with matrix isolation IR(infrared) and NIR(near infrared)spectroscopy. The NIR vibrations are more separated and therefore it is easier to distinguish different sizes of clusters in this region. The DMA clusters, up to DMA tetramer, have been optimized using density functional methods, and the geometries, binding energies and thermodynamic properties of DMA clusters were obtained. The computed frequencies and intensities of NH-stretching vibrations in the DMA clusters were used to interpret the experimental spectra. We have identified the fundamental transitions of the bonded NH-stretching vibration and the first overtone transitions of the bonded and free NH-stretching vibration in the DMA clusters. Based on the changes in vibrational intensities during the annealing processes, the growth of clusters was clearly observed. The results of annealing processes indicate that DMA molecules tend to form larger clusters with lower energies under matrix temperatures, which is also supported by the calculated reaction energies of cluster formation. 展开更多
关键词 matrix isolation Infrared(IR) spectroscopy Dimethylamine clusters Aerosol nucleation
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Effect of Reinforcement Clustering on Crack Initiation Mechanism in a Cast Hybrid Metal Matrix Composite during Low Cycle Fatigue 被引量:1
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作者 A. K. M. Asif Iqbal Yoshio Arai Wakako Araki 《Open Journal of Composite Materials》 2013年第4期97-106,共10页
The reinforcement distribution of metal matrix composites (MMCs) plays an important role in low cycle fatigue. Thus, it is essential to study the effect of reinforcement clustering on the crack initiation mechanism of... The reinforcement distribution of metal matrix composites (MMCs) plays an important role in low cycle fatigue. Thus, it is essential to study the effect of reinforcement clustering on the crack initiation mechanism of MMCs. In this study, the effect of reinforcement clustering on the microcrack initiation mechanism in a cast hybrid MMC reinforced with SiC particles and Al2O3 whiskers was investigated experimentally and numerically. Experimental results showed that microcracks always initiated in the particle-matrix interface, located in the cluster of the reinforcements. The interface debonding occurred in the fracture which created additional secondary microcracks due to continued fatigue cycling. The microcrack coalesced with other nearby microcracks caused the final fracture. To validate the experimental results on the microcrack initiation, three dimensional unit cell models using finite element method (FEM) were developed. The stress distribution in both the reinforcement clustering and non-clustering regions was analyzed. The numerical analysis showed that high stresses were developed on the reinforcements located in the clustering region and stress concentration occurred on the particle-matrix interface. The high volume fraction reinforced hybrid clustering region experienced greater stresses than that of the SiC particulate reinforced clustering region and low volume fraction reinforced hybrid clustering region. Besides, the stresses developed on the non-clustering region with particle-whisker series orientation were reasonably higher than that of the non-clustering region with particle-whisker parallel orientation. The high volume fraction reinforced hybrid clustering region is found to be highly vulnerable to initiate crack in cast hybrid MMC during low cycle fatigue. 展开更多
关键词 CAST Metal matrix Composites CRACK INITIATION REINFORCEMENT clusterING Low CYCLE Fatigue
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Clustering Student Discussion Messages on Online Forumby Visualization and Non-Negative Matrix Factorization
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作者 Xiaodi Huang Jianhua Zhao +1 位作者 Jeff Ash Wei Lai 《Journal of Software Engineering and Applications》 2013年第7期7-12,共6页
The use of online discussion forum can?effectively engage students in their studies. As the number of messages posted on the forum is increasing, it is more difficult for instructors to read and respond to them in a p... The use of online discussion forum can?effectively engage students in their studies. As the number of messages posted on the forum is increasing, it is more difficult for instructors to read and respond to them in a prompt way. In this paper, we apply non-negative matrix factorization and visualization to clustering message data, in order to provide a summary view of messages that disclose their deep semantic relationships. In particular, the NMF is able to find the underlying issues hidden in the messages about which most of the students are concerned. Visualization is employed to estimate the initial number of clusters, showing the relation communities. The experiments and comparison on a real dataset have been reported to demonstrate the effectiveness of the approaches. 展开更多
关键词 Online FORUM cluster Non-Negative matrix FACTORIZATION VISUALIZATION
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Clustering with Weighted Hyperlink and Sub Similarity Matrix
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作者 吴萍 宋瀚涛 +1 位作者 张利萍 吴正宇 《Journal of Beijing Institute of Technology》 EI CAS 2006年第2期177-180,共4页
A web page clustering algorithm called PageCluster and the improved algorithm ImPageCluster solving overlapping are proposed. These methods not only take the web structure and page hyperlink into account, but also con... A web page clustering algorithm called PageCluster and the improved algorithm ImPageCluster solving overlapping are proposed. These methods not only take the web structure and page hyperlink into account, but also consider the importance of each page which is described as in-weight and out-weight. Compared with the traditional clustering methods, the experiments show that the runtimes of the proposed algorithms are less with the improved accuracies. 展开更多
关键词 clusterING web page HYPERLINK similarity matrix Pagecluster ImPagecluster
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用Norm Matrix实现自组织映射网络的可视化 被引量:1
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作者 郭景峰 石丽红 《小型微型计算机系统》 CSCD 北大核心 2013年第11期2630-2634,共5页
自组织映射(SOM)算法已经被证实是一种非常有效的实现高维数据可视化的工具.但是SOM算法产生的结果——自组织映射网络必须借助于其他方法实现可视化,针对自组织映射网络的可视化方法 U-Matrix不能区分分离不明显的聚类的弊端,提出一种... 自组织映射(SOM)算法已经被证实是一种非常有效的实现高维数据可视化的工具.但是SOM算法产生的结果——自组织映射网络必须借助于其他方法实现可视化,针对自组织映射网络的可视化方法 U-Matrix不能区分分离不明显的聚类的弊端,提出一种新的可视化方法—Norm Matrix(N-Matrix),N-Matrix计算自组织映射网络的输出神经元权向量的范数,区别空间中不同神经元的绝对距离,并结合自组织映射网络特有的保持数据之间的拓扑邻域关系的性质,实现对自组织映射网络的可视化.实验结果证明,N-Matrix不仅可以实现分离明显聚类的可视化,还可以较好的实现分离不明显的聚类的可视化. 展开更多
关键词 自组织映射 N-矩阵 相对距离 绝对距离 不明显聚类 可视化
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PageCluster:一种Web页面层次聚类方法
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作者 吴萍 宋瀚涛 姜峰 《计算机工程与应用》 CSCD 北大核心 2004年第29期84-86,共3页
提出了Web页面聚类算法PageCluster及相应的改进算法ImPageCluster。该方法在兼顾Web站点结构和页面链接的同时,基于各个页面的重要程度对各个超链接进行赋权。与传统聚类算法相比,该算法不需要事先给定相似度阈值。实验结果证实了该算... 提出了Web页面聚类算法PageCluster及相应的改进算法ImPageCluster。该方法在兼顾Web站点结构和页面链接的同时,基于各个页面的重要程度对各个超链接进行赋权。与传统聚类算法相比,该算法不需要事先给定相似度阈值。实验结果证实了该算法的可行性和高效性。 展开更多
关键词 聚类 WEB页面 超链接 相似矩阵 Pagecluster ImPagecluster
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Flatness Control Based on Dynamic Effective Matrix for Cold Strip Mills 被引量:24
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作者 LIU Hongmin HE Haitao +1 位作者 SHAN Xiuying JIANG Guangbiao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第2期287-296,共10页
Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the im... Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced: the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method. 展开更多
关键词 cold strip mill flatness control dynamic effective matrix cluster fuzzy neural network
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A Fast Multi-tasking Solution: NMF-Theoretic Co-clustering for Gear Fault Diagnosis under Variable Working Conditions 被引量:7
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作者 Fei Shen Chao Chen +1 位作者 Jiawen Xu Ruqiang Yan 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2020年第1期182-196,共15页
Most gear fault diagnosis(GFD)approaches su er from ine ciency when facing with multiple varying working conditions at the same time.In this paper,a non-negative matrix factorization(NMF)-theoretic co-clustering strat... Most gear fault diagnosis(GFD)approaches su er from ine ciency when facing with multiple varying working conditions at the same time.In this paper,a non-negative matrix factorization(NMF)-theoretic co-clustering strategy is proposed specially to classify more than one task at the same time using the high dimension matrix,aiming to o er a fast multi-tasking solution.The short-time Fourier transform(STFT)is first used to obtain the time-frequency features from the gear vibration signal.Then,the optimal clustering numbers are estimated using the Bayesian information criterion(BIC)theory,which possesses the simultaneous assessment capability,compared with traditional validity indexes.Subsequently,the classical/modified NMF-based co-clustering methods are carried out to obtain the classification results in both row and column tasks.Finally,the parameters involved in BIC and NMF algorithms are determined using the gradient ascent(GA)strategy in order to achieve reliable diagnostic results.The Spectra Quest’s Drivetrain Dynamics Simulator gear data sets were analyzed to verify the e ectiveness of the proposed approach. 展开更多
关键词 GEAR fault diagnosis Non-negative matrix FACTORIZATION CO-clusterING VARYING working conditions
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Nanogold Synthesis Using Matrix Mono Glyceryl Stearate as Antiaging Compounds in Modern Cosmetics 被引量:1
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作者 Titik Taufikurohmah I Gusti Made Sanjaya Achmad Syahrani 《材料科学与工程(中英文A版)》 2011年第6期857-864,共8页
关键词 单硬脂酸甘油酯 合成温度 纳米金 化妆品 矩阵 化合物 抗衰老 纳米材料
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基于稀疏表示的Data Matrix码图像修复算法 被引量:1
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作者 陈庆然 许义宝 李新华 《计算机技术与发展》 2018年第1期60-63,68,共5页
稀疏表示理论凭借其建模简单、鲁棒性高与抗干扰能力强等优势成为研究热点,将稀疏理论应用于图像修复已成为图像处理领域新的研究方向。针对工业现场中常出现的被遮挡而不能识别的二维码图像,提出一种基于稀疏表示模型的块聚类图像修复... 稀疏表示理论凭借其建模简单、鲁棒性高与抗干扰能力强等优势成为研究热点,将稀疏理论应用于图像修复已成为图像处理领域新的研究方向。针对工业现场中常出现的被遮挡而不能识别的二维码图像,提出一种基于稀疏表示模型的块聚类图像修复算法。依据待修复图像内的有效信息,以固定重叠像素的方式将图像分块,分别对图像块使用欧几里得距离进行训练匹配,将得到的具有相似结构的图像块聚类为结构组作为图像稀疏表示的基本单位,利用每个结构组的估计来快速学习字典。通过使用分离迭代与优化梯度算法对组稀疏表示模型的L1范数最小化问题进行求解,提高了修复算法的鲁棒性。实验结果表明,该算法能够很好地修复被遮挡、划痕或像素丢失等受损的Data Matrix码图像,较大地提高了条码的识别率。 展开更多
关键词 DATA matrix 图像修复 块聚类 稀疏表示
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FH Sequences Selected Based on Clustering Analysis 被引量:1
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作者 Huabin Yang Deyu Wang 《通讯和计算机(中英文版)》 2010年第8期58-61,共4页
关键词 聚类分析算法 跳频序列 基础 空间结构特征 无线电网络 空间映射 跳频通信 碰撞概率
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Neural network-based matrix effect correction in EDXRF analysis 被引量:4
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作者 TUO Xianguo CHENG Bo MU Keliang LI Zhe 《Nuclear Science and Techniques》 SCIE CAS CSCD 2008年第5期278-281,共4页
In this paper we discuss neural network-based matrix effect correction in energy dispersive X-ray fluorescence (EDXRF) analysis,with detailed algorithm to classify the samples.The method can correct the matrix effect ... In this paper we discuss neural network-based matrix effect correction in energy dispersive X-ray fluorescence (EDXRF) analysis,with detailed algorithm to classify the samples.The method can correct the matrix effect effectively through classifying the samples automatically,and influence of X-ray absorption and enhancement by major elements of the samples is reduced.Experiments for the complex matrix effect correction in EDXRF analysis of samples in Pangang showed improved accuracy of the elemental analysis result. 展开更多
关键词 能量耗散X射线荧光分析 神经网络 聚类分析 基体效应 烧结矿物
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Group decision-making method based on entropy and experts cluster analysis 被引量:12
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作者 Xuan Zhou Fengming Zhang Xiaobin Hui Kewu Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第3期468-472,共5页
According to the aggregation method of experts' evaluation information in group decision-making,the existing methods of determining experts' weights based on cluster analysis take into account the expert's preferen... According to the aggregation method of experts' evaluation information in group decision-making,the existing methods of determining experts' weights based on cluster analysis take into account the expert's preferences and the consistency of expert's collating vectors,but they lack of the measure of information similarity.So it may occur that although the collating vector is similar to the group consensus,information uncertainty is great of a certain expert.However,it is clustered to a larger group and given a high weight.For this,a new aggregation method based on entropy and cluster analysis in group decision-making process is provided,in which the collating vectors are classified with information similarity coefficient,and the experts' weights are determined according to the result of classification,the entropy of collating vectors and the judgment matrix consistency.Finally,a numerical example shows that the method is feasible and effective. 展开更多
关键词 group decision-making judgment matrix ENTROPY information similarity coefficient cluster analysis.
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Fuzzy Clustering Method for Web User Based on Pages Classification 被引量:2
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作者 ZHANLi-qiang LIUDa-xin 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第5期553-556,共4页
A new method for Web users fuzzy clustering based on analysis of user interest characteristic is proposed in this article. The method first defines page fuzzy categories according to the links on the index page of the... A new method for Web users fuzzy clustering based on analysis of user interest characteristic is proposed in this article. The method first defines page fuzzy categories according to the links on the index page of the site, then computes fuzzy degree of cross page through aggregating on data of Web log. After that, by using fuzzy comprehensive evaluation method, the method constructs user interest vectors according to page viewing times and frequency of hits, and derives the fuzzy similarity matrix from the interest vectors for the Web users. Finally, it gets the clustering result through the fuzzy clustering method. The experimental results show the effectiveness of the method. Key words Web log mining - fuzzy similarity matrix - fuzzy comprehensive evaluation - fuzzy clustering CLC number TP18 - TP311 - TP391 Foundation item: Supported by the Natural Science Foundation of Heilongjiang Province of China (F0304)Biography: ZHAN Li-qiang (1966-), male, Lecturer, Ph. D. research direction: the theory methods of data mining and theory of database. 展开更多
关键词 Web log mining fuzzy similarity matrix fuzzy comprehensive evaluation fuzzy clustering
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Semi-Supervised Clustering Fingerprint Positioning Algorithm Based on Distance Constraints
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作者 Ying Xia Zhongzhao Zhang +1 位作者 Lin Ma Yao Wang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第6期55-61,共7页
With the rapid development of WLAN( Wireless Local Area Network) technology,an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online computation.In this paper,... With the rapid development of WLAN( Wireless Local Area Network) technology,an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online computation.In this paper,it proposes a novel fingerprint positioning algorithm known as semi-supervised affinity propagation clustering based on distance function constraints. We show that by employing affinity propagation techniques,it is able to use a fractional labeled data to adjust similarity matrix of signal space to cluster reference points with high accuracy. The semi-supervised APC uses a combination of machine learning,clustering analysis and fingerprinting algorithm. By collecting data and testing our algorithm in a realistic indoor WLAN environment,the experimental results indicate that the proposed algorithm can improve positioning accuracy while reduce the online localization computation,as compared with the widely used K nearest neighbor and maximum likelihood estimation algorithms. 展开更多
关键词 wireless local area network(WLAN) SEMI-SUPERVISED similarity matrix clusterING affinity propagation
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Cluster exponential synchronization of a class of complex networks with hybrid coupling and time-varying delay 被引量:1
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作者 王军义 张化光 +1 位作者 王占山 梁洪晶 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第9期324-334,共11页
This paper deals with the cluster exponential synchronization of a class ot complex networks wlm nyorm coupm^g and time-varying delay. Through constructing an appropriate Lyapunov-Krasovskii functional and applying th... This paper deals with the cluster exponential synchronization of a class ot complex networks wlm nyorm coupm^g and time-varying delay. Through constructing an appropriate Lyapunov-Krasovskii functional and applying the theory of the Kronecker product of matrices and the linear matrix inequality (LMI) technique, several novel sufficient conditions for cluster exponential synchronization are obtained. These cluster exponential synchronization conditions adopt the bounds of both time delay and its derivative, which are less conservative. Finally, the numerical simulations are performed to show the effectiveness of the theoretical results. 展开更多
关键词 complex network cluster exponential synchronization linear matrix inequality time-varying de-lay
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A Novel Minkowski-distance-based Consensus Clustering Algorithm
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作者 De-Gang Xu Pan-Lei Zhao +2 位作者 Chun-Hua Yang Wei-Hua Gui Jian-Jun He 《International Journal of Automation and computing》 EI CSCD 2017年第1期33-44,共12页
Consensus clustering is the problem of coordinating clustering information about the same data set coming from different runs of the same algorithm. Consensus clustering is becoming a state-of-the-art approach in an i... Consensus clustering is the problem of coordinating clustering information about the same data set coming from different runs of the same algorithm. Consensus clustering is becoming a state-of-the-art approach in an increasing number of applications. However, determining the optimal cluster number is still an open problem. In this paper, we propose a novel consensus clustering algorithm that is based on the Minkowski distance. Fusing with the Newman greedy algorithm in complex networks, the proposed clustering algorithm can automatically set the number of clusters. It is less sensitive to noise and can integrate solutions from multiple samples of data or attributes for processing data in the processing industry. A numerical simulation is also given to demonstrate the effectiveness of the proposed algorithm. Finally, this consensus clustering algorithm is applied to a froth flotation process. 展开更多
关键词 Minkowski distance consensus clustering similarity matrix process data froth flotation.
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Theory-Intelligent Dynamic Matrix Model of Flatness Control for Cold Rolled Strips 被引量:12
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作者 LIU Hong-min SHAN Xiu-ying JIA Chun-yu 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2013年第8期1-7,共7页
In order to increase the precision of flatness control, considering the principle and the measured data of rolling process essence, the theory-intelligent dynamic matrix model of flatness control is established by usi... In order to increase the precision of flatness control, considering the principle and the measured data of rolling process essence, the theory-intelligent dynamic matrix model of flatness control is established by using theory and in-telligent methods synthetically. The network model for rapidly calculating the theory effective matrix is established by the BP network optimized by the particle swarm algorithm. The network model for rapidly calculating the meas- urement effective matrix is established by the RBF network optimized by the cluster algorithm. The flatness control model can track the practical situation of roiling process by on-line selVlearning. The scheme for flatness control quantity calculation is established by combining the theory control matrix and the measurement control matrix. The simulation result indicates that the establishment of theory-intelligent dynamic matrix model of flatness control with stable control process and high precision supplies a new way and method for studying flatness on-line control model. 展开更多
关键词 flatness control dynamic matrix theory model measured data neural network particle swarm cluster
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