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A cluster line approach to finding new Fe-B-Y-Nb-Zr bulk metallic glasses
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作者 Nigel Pemberton-Pigott 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2007年第S1期26-30,共5页
The glass forming ability of the [(Fe12/13Y1/13)100?xBx]96Nb2Zr2 (x=9–26) system was investigated using a series of cluster lines. Three types of clusters, an icosahedron (Fe12Y), a capped Archimedes anti-prism (Fe8B... The glass forming ability of the [(Fe12/13Y1/13)100?xBx]96Nb2Zr2 (x=9–26) system was investigated using a series of cluster lines. Three types of clusters, an icosahedron (Fe12Y), a capped Archimedes anti-prism (Fe8B3) and a capped trigonal prism (Fe9B), as well as a binary eutectic (Fe83B17) were considered. Bulk glassy alloy rods of 3 mm in diameter were synthesized using a copper mold suction-casting method. The glass transition temperature was observed for all samples in the boron range of 15.9at%-25.7at%, with the alloy at 15.9at% of boron having the best thermal properties. The ferrous-based bulk metallic glasses (BMG) obtained have high reduced glass transition temperatures with the maximum reaching 0.63 and large supercooled liquid regions with the maximum reaching 111 K. Magnetic testing revealed a large value of coercive force and remanent magnetization, being 11 kA/m and 0.1 T, re- spectively. 展开更多
关键词 bulk metallic glasses Fe-B-Y-Nb-Zr alloys composition design cluster line
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Cluster Analysis of Chinese Pumpkin Inbred Lines 被引量:7
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作者 杜晓华 李小梅 李新峥 《Agricultural Science & Technology》 CAS 2008年第4期104-107,共4页
A cluster analysis was carried out based on Euclidean genetic distances through UPGMA method in Chinese pumpkin inbred lines.7 important agronomic traits of 46 Chinese pumpkin inbred lines were investigated.The result... A cluster analysis was carried out based on Euclidean genetic distances through UPGMA method in Chinese pumpkin inbred lines.7 important agronomic traits of 46 Chinese pumpkin inbred lines were investigated.The result indicated that 46 pumpkin inbred lines were clustered into 4 groups and the inter-groups distances was larger than that in intra-group.The genetic distances of parents were related to F1 performance and the results of cluster would increase effectiveness in the Chinese pumpkin crossing breeding. 展开更多
关键词 CHINESE PUMPKIN INBRED lineS cluster
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An on-line scaling method for improving scalability of a database cluster
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作者 JANG Yong ll LEE Chung ho +1 位作者 LEE Jae dong BAE Hae young 《重庆邮电学院学报(自然科学版)》 2004年第5期71-77,共7页
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on line scaling without interrupting service. To support more client’s queries... The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on line scaling without interrupting service. To support more client’s queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on line scaling method. Our method improves the existing on line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e., we decrease the number of data copy by reusing the backup data. Also, our on line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time. 展开更多
关键词 数据库串 在线缩放方法 可量测性 改进方法
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Document Clustering with Evolutionary Systems through Straight-Line Programs “<i>slp</i>”
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作者 José Luis Castillo Sequera José Raúl Fernández del Castillo Diez León Gonzalez Sotos 《Journal of Intelligent Learning Systems and Applications》 2012年第4期303-318,共16页
In this paper, we show a clustering method supported on evolutionary algorithms with the paradigm of linear genetic programming. “The Straight-Line Programs (slp)”, which uses a data structure which will be useful t... In this paper, we show a clustering method supported on evolutionary algorithms with the paradigm of linear genetic programming. “The Straight-Line Programs (slp)”, which uses a data structure which will be useful to represent collections of documents. This data structure can be seen as a linear representation of programs, as well as representations in the form of graphs. It has been used as a theoretical model in Computer Algebra, and our purpose is to reuse it in a completely different context. In this case, we apply it to the field of grouping library collections through evolutionary algorithms. We show its efficiency with experimental data we got from traditional library collections. 展开更多
关键词 clustering Genetic Algorithm Data Mining STRAIGHT line PROGRAMS
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Cluster-based composition rules for ternary alloy systems 被引量:1
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作者 Chuang Dong1, 2), Qing Wang1), Weirong Chen1), Qingyu Zhang1), Jianbing Qiang1), and Yingmin Wang1) 1) State Key Laboratory of Materials Modification, Dalian University of Technology, Dalian 116024, China 2) International Center for Materials Physics, Chinese Academy of Sciences, Shenyang 110016, China 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2007年第S1期1-3,共3页
The cluster-based composition rule in ternary alloy systems including quasicrystals, bulk metallic glasses, crystalline phases and Lave phases-related body-centered cubic (BCC) solid solution forming systems was summa... The cluster-based composition rule in ternary alloy systems including quasicrystals, bulk metallic glasses, crystalline phases and Lave phases-related body-centered cubic (BCC) solid solution forming systems was summarized. The so-called cluster line in a ternary phase diagram refers to a straight composition line linking a specific binary cluster to the third element. The compo- sition ranges of quasicrystals and bulk metallic glasses can be determined by the direct use of cluster lines, where two cluster lines intersect at the optimum phase forming composition. Furthermore, the alloys on the cluster line in Laves phase-related BCC solid solution alloy systems have larger hydrogen storage capacities. 展开更多
关键词 cluster line composition design QUASICRYSTALS bulk metallic glasses hydrogen storage alloys
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Sonar Image Detection Algorithm Based on Two-Phase Manifold Partner Clustering 被引量:1
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作者 Xingmei Wang Zhipeng Liu +1 位作者 Jianchuang Sun Shu Liu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第4期105-114,共10页
According to the characteristics of sonar image data with manifold feature,the sonar image detection method based on two-phase manifold partner clustering algorithm is proposed. Firstly,K-means block clustering based ... According to the characteristics of sonar image data with manifold feature,the sonar image detection method based on two-phase manifold partner clustering algorithm is proposed. Firstly,K-means block clustering based on euclidean distance is proposed to reduce the data set. Mean value,standard deviation,and gray minimum value are considered as three features based on the relatinship between clustering model and data structure. Then K-means clustering algorithm based on manifold distance is utilized clustering again on the reduced data set to improve the detection efficiency. In K-means clustering algorithm based on manifold distance,line segment length on the manifold is analyzed,and a new power function line segment length is proposed to decrease the computational complexity. In order to quickly calculate the manifold distance,new allsource shortest path as the pretreatment of efficient algorithm is proposed. Based on this,the spatial feature of the image block is added in the three features to get the final precise partner clustering algorithm. The comparison with the other typical clustering algorithms demonstrates that the proposed algorithm gets good detection result. And it has better adaptability by experiments of the different real sonar images. 展开更多
关键词 SONAR image K-means clusterING MANIFOLD distance line SEGMENT length
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Line profile studies of hydrodynamical models of cometary compact H II regions
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作者 Feng-Yao Zhu Qing-Feng Zhu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第6期828-848,共21页
We simulate the evolution of cometary H II regions based on several champagne flow models and bow shock models, and calculate the profiles of the [Ne II] fine-structure line at 12.81 μm, the H30α recombination line ... We simulate the evolution of cometary H II regions based on several champagne flow models and bow shock models, and calculate the profiles of the [Ne II] fine-structure line at 12.81 μm, the H30α recombination line and the [Ne III] finestructure line at 15.55 μm for these models at different inclinations of 0°, 30° and 60°. We find that the profiles in the bow shock models are generally different from those in the champagne flow models, but the profiles in the bow shock models with lower stellar velocity (≤ 5 km s^-1) are similar to those in the champagne flow models. In champagne flow models, both the velocity of peak flux and the flux weighted central velocities of all three lines point outward from molecular clouds. In bow shock models, the directions of these velocities depend on the speed of stars. The central velocities of these lines are consistent with the stellar motion in the high stellar speed cases, but they are opposite directions from the stellar motion in the low speed cases. We notice that the line profiles from the slit along the symmetrical axis of the projected 2D image of these models are useful for distinguishing bow shock models from champagne flow models. It is also confirmed by the calculation that the flux weighted central velocity and the line luminosity of the [Ne III] line can be estimated from the [Ne II] line and the H30α line. 展开更多
关键词 H II regions -- ISM kinematics and dynamics clusters -- line profiles
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Chlorophyll Concentration and Morphological Diversity in Corn Lines at Different Vegetative Stages
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作者 Mariano Mendoza Elos Gilberto Rodríguez Pérez +7 位作者 Francisco Cervantes Ortíz Luis Patricio Guevara Acevedo Enrique Andrio Enríquez Ma. Del Carmen Ojeda Zacarías Isabel Presa Figuereo Sergio Alfredo Rodríguez Herrera José Antonio Rangel Lucio José Guadalupe Rivera Reyes 《American Journal of Plant Sciences》 2016年第7期1067-1076,共10页
The objective of this study was to assess the chlorophyll content of corn lines at different vegetative stages and the diversity between them. The study was conducted in the experimental field of the Roque Institute o... The objective of this study was to assess the chlorophyll content of corn lines at different vegetative stages and the diversity between them. The study was conducted in the experimental field of the Roque Institute of Technology (ITR) located in Roque, Celaya, Guanajuato, Mexico. We used 32 corn lines from CIMMYT and four lines from the breeding program of the ITR. The evaluation was conducted in the spring-summer cycle of 2014 at two planting dates. We used a completely randomized block design with three replications. The experimental unit consisted of two rows of five linear meters with a distance of 0.75 meters between rows. Chlorophyll was measured at six different stages: V6, VT, R3, R4, R5 and MF. The agronomic variables recorded were: PH, CH, LAC, LBC, FF, MF, PM, CC, CL, DC, RC, KR and GY. The results of the analysis of variance showed significant differences between lines, dates and their interaction. On average, 18 lines were found with chlorophyll concentrations above 51 SPAD units in the two environments. This indicated that these materials had a high potential for field performance. Using cluster analysis UPGMA method, we identified seven groups for chlorophyll and eight groups for agronomic characteristics for a breeding program. The groups were associated to the homogeneous characteristics of each variable. 展开更多
关键词 Chlorophyll Content Phenological Stages clusters and Corn lines
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Atomic epn(ep) Spin Models and Spectral Lines
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作者 Daekyoum Kim Baik-Hyon Ha 《American Journal of Analytical Chemistry》 2015年第13期1030-1037,共8页
We confirmed that how many kinds of epn spins the atoms have by calculating heat capacity of metals according to energy levels in the previous reference. To know more the spin models of epn of hydrogen and helium are ... We confirmed that how many kinds of epn spins the atoms have by calculating heat capacity of metals according to energy levels in the previous reference. To know more the spin models of epn of hydrogen and helium are imagined and their line spectra are counted. And the explanation of interference is discussed. Gas atoms make line spectra by optical interference. Solid atoms make them by exciting the lowest epns of their cluster first. They all make s, p energy orbit. One axis is composed of two epns. 1s or 2s of atoms except for lithium generally makes the symmetric axis. When each energy level is filled up by epns, these are symmetrically paired first. The atoms which fit the number of line spectra correctly by optical interference are hydrogen and helium. By counting the number of alignments of epns spins within the cluster, the atoms which fit the number of line spectra correctly are lithium, beryllium and phosphorus. The number of line spectra of the rest atoms which we have counted approaches the experimented numbers approximately, not correctly. 展开更多
关键词 ATOMIC Model ATOMIC cluster SPECTRAL lineS RESONANCE
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High Dimensional Cluster Analysis Using Path Lengths
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作者 Kevin Mcilhany Stephen Wiggins 《Journal of Data Analysis and Information Processing》 2018年第3期93-125,共33页
A hierarchical scheme for clustering data is presented which applies to spaces with a high number of dimensions (). The data set is first reduced to a smaller set of partitions (multi-dimensional bins). Multiple clust... A hierarchical scheme for clustering data is presented which applies to spaces with a high number of dimensions (). The data set is first reduced to a smaller set of partitions (multi-dimensional bins). Multiple clustering techniques are used, including spectral clustering;however, new techniques are also introduced based on the path length between partitions that are connected to one another. A Line-of-Sight algorithm is also developed for clustering. A test bank of 12 data sets with varying properties is used to expose the strengths and weaknesses of each technique. Finally, a robust clustering technique is discussed based on reaching a consensus among the multiple approaches, overcoming the weaknesses found individually. 展开更多
关键词 clusterING PATH LENGTH CONSENSUS N-Dimensional line of SIGHT
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Resistance Evaluation to Sheath Blight in Transgenic Rice Lines
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作者 LIAi-hong XuXin-ping +4 位作者 DAIZheng-yuan CHENZong-xiang LIBao-jian ZHANGHong-xi PANXue-biao 《Rice science》 SCIE 2004年第3期95-100,共6页
Resistance of forty-one homozygous rice lines transformed with chitinase gene (RC24) and β-1,3 -glucanse gene β-1,3-Glu) to sheath blight was analyzed by inoculation. Among different lines, the resistance had signif... Resistance of forty-one homozygous rice lines transformed with chitinase gene (RC24) and β-1,3 -glucanse gene β-1,3-Glu) to sheath blight was analyzed by inoculation. Among different lines, the resistance had significant differences according to the result by cluster analysis. The lines could be categorized into resistant, moderately resistant, moderately susceptible and susceptible types, while 92.1% of which belonging to moderately resistant or moderately susceptible type. For different resistant or susceptible lines, the resistance to rice sheath blight was remarkable correlated with the chitinase activity of transgenic lines except resistant type lines, in which enzyme activity coded by target gene was lower than moderately resistant type. The chitinase activity of transgenic lines tested at different time after inoculation or different organs of the same plant was uniform, which suggested that the expression of chitinase gene was constitutive in nature. Check varieties chitinase activity would change at different time after inoculation and reach a peak at sometime, but it had no difference at various pans of the same plant. 展开更多
关键词 RICE ttansgenic lines sheath blight resistance cluster analysis chitinase activity
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Rigidity Symmetry Line for Thermodynamic Fluid Equations-of-State
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作者 Leslie V. Woodcock 《Journal of Modern Physics》 2024年第5期613-633,共21页
We report progress towards a modern scientific description of thermodynamic properties of fluids following the discovery (in 2012) of a coexisting critical density hiatus and a supercritical mesophase defined by perco... We report progress towards a modern scientific description of thermodynamic properties of fluids following the discovery (in 2012) of a coexisting critical density hiatus and a supercritical mesophase defined by percolation transitions. The state functions density ρ(p,T), and Gibbs energy G(p,T), of fluids, e.g. CO<sub>2</sub>, H<sub>2</sub>O and argon exhibit a symmetry characterised by the rigidity, ω = (dp/dρ)<sub>T</sub>, between gaseous and liquid states along any isotherm from critical (T<sub>c</sub>) to Boyle (T<sub>B</sub>) temperatures, on either side of the supercritical mesophase. Here, using experimental data for fluid argon, we investigate the low-density cluster physics description of an ideal dilute gas that obeys Dalton’s partial pressure law. Cluster expansions in powers of density relate to a supercritical liquid-phase rigidity symmetry (RS) line (ω = ρ<sub>rs</sub>(T) = RT) to gas phase virial coefficients. We show that it is continuous in all derivatives, linear within stable fluid phase, and relates analytically to the Boyle-work line (BW) (w = (p/ρ)<sub>T</sub> = RT), and to percolation lines of gas (PB) and liquid (PA) phases by: ρ<sub>BW</sub>(T) = 2ρ<sub>PA</sub>(T) = 3ρ<sub>PB</sub>(T) = 3ρ<sub>RS</sub>(T)/2 for T T<sub>B</sub>. These simple relationships arise, because the higher virial coefficients (b<sub>n</sub>, n ≥ 4) cancel due to clustering equilibria, or become negligible at all temperatures (0 T T<sub>B</sub>)<sub> </sub>within the gas phase. The Boyle-work line (p/ρ<sub>BW</sub>)<sub>T</sub> is related exactly at lower densities as T → T<sub>B</sub>, and accurately for liquid densities, by ρ<sub>BW</sub>(T) = −(b<sub>2</sub>/b<sub>3</sub>)<sub>T</sub>. The RS line, ω(T) = RT, defines a new liquid-density ground-state physical constant (ρ<sub>RS</sub>(0) = (2/3)ρ<sub>BW</sub>(0) for argon). Given the gas-liquid rigidity symmetry, the entire thermodynamic state functions below T<sub>B</sub> are obtainable from b<sub>2</sub>(T). A BW-line ground-state crystal density ρ<sub>BW</sub>(0) can be defined by the pair potential minimum. The Ar<sub>2</sub> pair potential, ∅ij</sub>(r<sub>ij</sub>) determines b<sub>2</sub>(T) analytically for all T. This report, therefore, advances the salient objective of liquid-state theory: an argon p(ρ,T) Equation-of-state is obtained from ∅<sub>ij</sub>(r<sub>ij</sub>) for all fluid states, without any adjustable parameters. 展开更多
关键词 Liquid-State Theory cluster Physics Percolation lines Fluid Thermodynamics Boyle line Rigidity-Symmetry line
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Comparisons of Several Similarity Coefficients for Cluster Analysis of Hot Pepper Germplasm Resources
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作者 Yu REN Guangsui YANG +2 位作者 Zhiqun ZHANG Xia KONG Junmei YIN 《Agricultural Biotechnology》 CAS 2014年第5期24-28,共5页
An appropriate genetic similarity coefficient is particularly important for accurately estimating the genetic similarity and phylogenetic relationship between individuals and evaluating the genetic diversity of popula... An appropriate genetic similarity coefficient is particularly important for accurately estimating the genetic similarity and phylogenetic relationship between individuals and evaluating the genetic diversity of populations. In this study, five genetic similarity coefficients were compared for analysis of phylogenetic relationship among 31 hot pepper inbred lines based on SRAP. The applicability of different genetic similarity coefficient was investigated by means of SRAP data of hot pepper inbred lines. According to the experimental results, the variation ranges of Nei & Li, Jaceard, Sorensen, Simple matching and Yule coefficients were 0. 598 - 0. 973, 0. 427 - 0. 947, 0. 598 - 0. 973, 0.427 - 0. 947 and 0. 133 - 0. 997, respectively. Results of cluster analysis based on different similarity coefficients varied greatly. To be specific, clustering results based on Nei & Li, Jaccard and Sorensen coefficients were consistent; clustering with Simple matching and Yule coef ficients led to consistent classification of category in different order and slightly different classification of subcategory. Comprehensively comparing the results of cluster analysis and the dendrograms of hot pepper inbred lines, Yule coefficient is suitable for SRAP analysis of hot pepper. 展开更多
关键词 Hot pepper Inbred lines SRAP Genetic similarity coefficient cluster analysis
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Genetic Diversity among Parents of Hybrid Rice Based on Cluster Analysis of Morphological Traits and Simple Sequence Repeat Markers 被引量:3
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作者 WANG Sheng-jun Lu Zuo-mei WAN Jian-min 《Rice science》 SCIE 2006年第3期155-160,共6页
The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one ... The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one entries were assigned into two clusters (i.e. early or medium-maturing cluster; medium or late-maturing cluster) and further assigned into six sub-clusters based on morphological trait cluster analysis, The early or medium-maturing cluster was composed of 15 maintainer lines, four early-maturing restorer lines and two thermo-sensitive genic male sterile lines, and the medium or late-maturing cluster included 16 restorer lines and 4 medium or late-maturing maintainer lines. Moreover, the SSR cluster analysis classified 41 entries into two groups (i.e, maintainer line group and restorer line group) and seven sub-groups. The maintainer line group consisted of all 19 maintainer lines, two thermo-sensitive genic male sterile lines, while the restorer line group was composed of all 20 restorer lines. The SSR analysis fitted better with the pedigree information. From the views on hybrid rice breeding, the results suggested that SSR analysis might be a better method to study the diversity of parental lines in indica hybrid rice. 展开更多
关键词 parental lines hybrid rice morphological trait simple sequence repeats clustering analysis genetic diversity PEDIGREE
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基于图卷积神经网络的露天矿车道路边界检测算法 被引量:1
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作者 秦学斌 许爱珍 周毓凡 《金属矿山》 北大核心 2025年第3期181-188,共8页
由于矿山道路没有路肩且道路边界线十分模糊,因此区分道路边界线之内的可行驶区域与边界线以外的非可行驶区域成为亟待解决的问题。为提升露天矿车行驶的安全性,提出了一种基于图卷积神经网络的露天矿车道路边界检测算法。首先利用kd-t... 由于矿山道路没有路肩且道路边界线十分模糊,因此区分道路边界线之内的可行驶区域与边界线以外的非可行驶区域成为亟待解决的问题。为提升露天矿车行驶的安全性,提出了一种基于图卷积神经网络的露天矿车道路边界检测算法。首先利用kd-tree算法和基于体素化的八叉树滤波算法构成的复合索引结构对点云数据进行精简和滤波,剔除点云数据中的异常点和高噪声点;再通过基于K-means聚类对精简后的点云数据进行图卷积神经网络运算提取出地面点,非地面点通过聚类方法寻找邻域构成三角面,利用三角面的法向量拟合非地面即得到曲面;最后计算拟合最优地面和非地面的交线即为所求的道路边界线。试验结果表明:提出的道路边界检测算法能很好地检测出边界线,为矿山道路无人驾驶提供安全范围,有助于提升无人运行矿车驾驶的安全性。 展开更多
关键词 点云滤波 kd-tree算法 K-MEANS聚类 图卷积网络 边界线检测
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采用方向自适应密度聚类自动检测侧扫声呐图像海底线 被引量:2
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作者 王爱学 金绍华 +2 位作者 刘天阳 查文富 刘畅 《武汉大学学报(信息科学版)》 北大核心 2025年第4期674-683,698,共11页
侧扫声呐是获取海底地貌图像的主要手段之一,海底线是侧扫声呐瀑布图像最显著的特征,准确检测和跟踪海底线是侧扫声呐数据精细处理的基础。受水体环境噪声、船体、水面及水体悬浮目标散射等干扰,传统阈值法及相关图像特征检测算法难以... 侧扫声呐是获取海底地貌图像的主要手段之一,海底线是侧扫声呐瀑布图像最显著的特征,准确检测和跟踪海底线是侧扫声呐数据精细处理的基础。受水体环境噪声、船体、水面及水体悬浮目标散射等干扰,传统阈值法及相关图像特征检测算法难以实现海底线自动、准确、高效提取。充分考虑侧扫声呐海底线的边缘特性及沿航迹向密集分布的空间特点,提出了一种边缘方向适应性密度聚类和聚类链筛选相结合的海底线检测方法。该方法通过高斯一阶导卷积模板及非极大值抑制实现高噪声图像边缘梯度和方向计算以及边缘特征的细化;通过设置窄带状搜索邻域,并依据边缘梯度方向实时调整搜索邻域的长轴,以实现对方向变化的线状特征的密度聚类;通过构建基于边缘特征密度聚类的海底线检测策略,包括设定经验范围、阈值法构建聚类种子集、长链原则、排他原则、对称原则、趋势延伸原则、修复原则等,以实现海底线边缘特征的快速密度聚类成链和海底线的筛选。实验验证和对比分析的结果表明,在持续噪声、复杂悬浮物等常见水体回波干扰下,所提方法在海底线检测的准确性和稳定性上优于传统阈值方法,且单呯平均检测耗时仅为0.661 ms。所提侧扫声呐图像海底线检测方法有较好的稳定性和干扰普适性,可在侧扫声呐数据采集和事后处理中推广应用。 展开更多
关键词 侧扫声呐 海底线跟踪 密度聚类 方向自适应
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基于改进空间密度聚类的电力线自动提取 被引量:2
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作者 齐智宇 王健 +1 位作者 赵艺龙 李志远 《应用激光》 北大核心 2025年第2期141-147,共7页
针对电力线点云提取过程中自动化程度低且结果易受参数影响出现欠分割或过分割的问题,结合机载激光雷达(light detection and ranging,LiDAR)点云数据的分布特点,提出一种基于改进空间密度聚类算法的激光点云电力线的提取方法。该方法... 针对电力线点云提取过程中自动化程度低且结果易受参数影响出现欠分割或过分割的问题,结合机载激光雷达(light detection and ranging,LiDAR)点云数据的分布特点,提出一种基于改进空间密度聚类算法的激光点云电力线的提取方法。该方法首先通过空间分割改进高程滤波算法完成电力线点云的粗提取;其次,利用基于距离-密度的方法和数学期望计算方法获得空间密度聚类的最佳参数,避免了繁杂的人工调参过程。实验结果显示,相较于空间密度聚类算法,所提算法效率显著提高,降低了约60%电力线提取时间,实现了单根电力线点云的自动化和高效提取。 展开更多
关键词 机载激光雷达 高程滤波 点云数据 空间密度聚类 电力线提取
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基于连锁电压形态辨识的大规模新能源外送系统单相故障性质识别方法
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作者 李振兴 朱益 +4 位作者 安喆 翁汉琍 李振华 王秋杰 谭洪 《中国电机工程学报》 北大核心 2025年第22期8819-8831,I0013,共14页
针对传统故障性质识别方案难以适应大规模外送系统电源侧新能源集群接入的问题,提出一种基于连锁电压形态辨识的故障性质识别方法。首先,明确非全相运行的电压特性以及新能源电源谐波馈出机理,关注新能源谐波作用下的电压波形总体特征,... 针对传统故障性质识别方案难以适应大规模外送系统电源侧新能源集群接入的问题,提出一种基于连锁电压形态辨识的故障性质识别方法。首先,明确非全相运行的电压特性以及新能源电源谐波馈出机理,关注新能源谐波作用下的电压波形总体特征,发现在瞬时性故障熄弧前后,线路单端电压存在显著的固有形态差异,而永久性故障的电压形态差异极小;其次,通过论证选取特征形态基准,连续扫描并计算电压差积分有效值(root-mean-square,RMS),稳定表征电压形态差异,构建基于自适应阈值的故障性质识别方法;最后,基于PSCAD的仿真验证表明,该方法不限制线路并联电抗器的配置情况,可靠性高,具备良好的抗噪能力,且不受故障位置、过渡电阻和新能源渗透率的影响,能够在电源侧新能源集群接入时实现故障性质的准确识别。 展开更多
关键词 新能源集群 故障性质识别 熄弧时刻 线路端电压 形态辨识
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基于机器视觉的极片定位引导算法
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作者 任永强 胡长路 臧昌禹 《组合机床与自动化加工技术》 北大核心 2025年第5期33-36,43,共5页
由于切叠机叠片之前需要对极片进行纠偏准备,为提高极片定位的精准度与速度,提出一种基于梯度方向改进K-means聚类算法,结合局部优化随机抽样一致性(random sampling consistency,RANSAC)算法获取定位坐标。首先,对图片进行降噪等预处... 由于切叠机叠片之前需要对极片进行纠偏准备,为提高极片定位的精准度与速度,提出一种基于梯度方向改进K-means聚类算法,结合局部优化随机抽样一致性(random sampling consistency,RANSAC)算法获取定位坐标。首先,对图片进行降噪等预处理减少外界干扰;基于Canny算子对图像边缘检测,采用多项式插值的方法得到矩形图像直角附近的亚像素级坐标;之后利用改进的K-means算法对边缘亚像素点进行聚类,实现边缘点的划分;结合改进的RANSAC算法拟合出两条相交的直线;最后提取4个直线交点,即图像4个直角拐点,以此确定极片短边中点。实验表明该算法所得中点的波动幅度较小,具有较高的鲁棒性,且定位速度较快,满足工程需求。 展开更多
关键词 梯度 K-MEANS聚类 亚像素 随机抽样一致性 直线拟合
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基于聚类与最优尺度法的宁乡雪茄品种优选
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作者 周紫丹 向世鹏 +5 位作者 陈治锋 胡俊杰 李洋洋 周世民 翟争光 李强 《云南农业大学学报(自然科学版)》 北大核心 2025年第2期58-67,共10页
【目的】筛选宁乡烟区优良的雪茄品种(系)。【方法】对宁乡烟区16个雪茄烟品种(系)的生长发育状况、品质指标等综合表现进行多角度K均值聚类,以品种(系)及其聚类结果为分类变量,用最优尺度法进行多元对应分析。【结果】参试品种(系)被... 【目的】筛选宁乡烟区优良的雪茄品种(系)。【方法】对宁乡烟区16个雪茄烟品种(系)的生长发育状况、品质指标等综合表现进行多角度K均值聚类,以品种(系)及其聚类结果为分类变量,用最优尺度法进行多元对应分析。【结果】参试品种(系)被聚为强、正常和弱3个生长势类别,较好、中等和较差3个感官类别,高氯高碱、中氯高碱和中氯中碱3个化学类别,茄衣型、茄芯型和兼用型3个工业用途类别。多元对应分析结果表明:宁乡烟区感官质量表现较好的雪茄烟品种(系)具有生长势正常、中氯高碱的特点,包括哈伯纳斯(茄衣型)、长雪1号(兼用型)、古巴7号(兼用型)和CX080(兼用型)。【结论】在无对照、参试品种多、观测维度和观测数据多的背景下,结合K均值聚类分析和最优尺度法能有效提高雪茄烟品种(系)筛选效率。宁乡烟区雪茄烟品种(系)哈伯纳斯、长雪1号、古巴7号和CX080的综合性状较为优良。 展开更多
关键词 雪茄 品种(系) 优选 聚类 最优尺度
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