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New two-dimensional fuzzy C-means clustering algorithm for image segmentation 被引量:4
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作者 周鲜成 申群太 刘利枚 《Journal of Central South University of Technology》 EI 2008年第6期882-887,共6页
To solve the problem of poor anti-noise performance of the traditional fuzzy C-means (FCM) algorithm in image segmentation, a novel two-dimensional FCM clustering algorithm for image segmentation was proposed. In this... To solve the problem of poor anti-noise performance of the traditional fuzzy C-means (FCM) algorithm in image segmentation, a novel two-dimensional FCM clustering algorithm for image segmentation was proposed. In this method, the image segmentation was converted into an optimization problem. The fitness function containing neighbor information was set up based on the gray information and the neighbor relations between the pixels described by the improved two-dimensional histogram. By making use of the global searching ability of the predator-prey particle swarm optimization, the optimal cluster center could be obtained by iterative optimization, and the image segmentation could be accomplished. The simulation results show that the segmentation accuracy ratio of the proposed method is above 99%. The proposed algorithm has strong anti-noise capability, high clustering accuracy and good segment effect, indicating that it is an effective algorithm for image segmentation. 展开更多
关键词 image segmentation fuzzy C-means clustering particle swarm optimization two-dimensional histogram
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Spatial distribution patterns of anorectal atresia/stenosis in China:Use of two-dimensional graph-theoretical clustering
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作者 Ping Yuan Liang Qiao +8 位作者 Li Dai Yan-Ping Wang Guang-Xuan Zhou Ying Han Xiao-Xia Liu Xun Zhang Yi Cao Juan Liang Jun Zhu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第22期2787-2793,共7页
AIM:To investigate the spatial distribution patterns of anorectal atresia/stenosis in China.METHODS:Data were collected from the Chinese Birth Defects Monitoring Network(CBDMN),a hospital-based congenital malformation... AIM:To investigate the spatial distribution patterns of anorectal atresia/stenosis in China.METHODS:Data were collected from the Chinese Birth Defects Monitoring Network(CBDMN),a hospital-based congenital malformations registry system.All fetuses more than 28 wk of gestation and neonates up to 7 d of age in hospitals within the monitoring sites of the CBDMN were monitored from 2001 to 2005.Two-dimensional graph-theoretical clustering was used to divide monitoring sites of the CBDMN into different clusters according to the average incidences of anorectal atresia/stenosis in the different monitoring sites.RESULTS:The overall average incidence of anorectal atresia/stenosis in China was 3.17 per 10000 from 2001 to 2005.The areas with the highest average incidences of anorectal atresia/stenosis were almost always focused in Eastern China.The monitoring sites were grouped into 6 clusters of areas.Cluster 1 comprised the monitoring sites in Heilongjiang Province,Jilin Province,and Liaoning Province;Cluster 2 was composed of those in Fujian Province,Guangdong Province,Hainan Province,Guangxi Zhuang Autonomous Region,south Hunan Province,and south Jiangxi Province;Cluster 3 consisted of those in Beijing Municipal City,Tianjin Municipal City,Hebei Province,Shandong Province,north Jiangsu Province,and north Anhui Province;Cluster 4 was made up of those in Zhejiang Province,Shanghai Municipal City,south Anhui Province,south Jiangsu Province,north Hunan Province,north Jiangxi Province,Hubei Province,Henan Province,Shanxi Province and Inner Mongolia Autonomous Region;Cluster 5 consisted of those in Ningxia Hui Autonomous Region,Gansu Province and Qinghai Province;and Cluster 6 included those in Shaanxi Province,Sichuan Province,Chongqing Municipal City,Yunnan Province,Guizhou Province,Xinjiang Uygur Autonomous Province and Tibet Autonomous Region.CONCLUSION:The fi ndings in this research allow the display of the spatial distribution patterns of anorectal atresia/stenosis in China.These will have important guiding significance for further analysis of relevant environmental factors regarding anorectal atresia/ stenosis and for achieving regional monitoring for anorectal atresia/stenosis. 展开更多
关键词 Spatial distribution Anorectal atresia/ stenosis two-dimensional graph-theoretical clustering Incidence Monitoring
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低碳视角下东北三省耕地利用生态效率及分区研究
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作者 盖兆雪 王子彤 赵映慧 《西南农业学报》 CSCD 北大核心 2024年第3期622-632,共11页
【目的】低碳视角下耕地利用生态效率及分区研究,对于区域耕地低碳利用和用地结构调整具有重要意义,是形成耕地数量、质量及生态“三位一体”保护格局,推进耕地生态文明建设的重要举措。【方法】构建低碳视角下耕地利用生态效率指标体系... 【目的】低碳视角下耕地利用生态效率及分区研究,对于区域耕地低碳利用和用地结构调整具有重要意义,是形成耕地数量、质量及生态“三位一体”保护格局,推进耕地生态文明建设的重要举措。【方法】构建低碳视角下耕地利用生态效率指标体系,借助超效率SBM模型(Super slacks-based measure)和ArcGIS软件揭示研究区耕地利用生态效率时空分异特征,并运用两维图论聚类法进行耕地利用生态分区,提出各分区方向。【结果】①2010—2020年研究区耕地利用生态效率呈波动下降趋势,核密度波峰呈“双峰—单峰—双峰”的分布特征,主峰由“宽峰”转变为“尖峰”,两极分化特征明显,地区差异逐渐缓解;②低效率型波峰由“双峰”向“单峰”转变,生态效率极化现象趋于好转;中效率型波峰为“一主一小”的双峰形态,生态效率呈现两极分化的区域聚集现象;高效率型主峰高度降低,生态效率内部差异逐步减小;③耕地利用生态效率存在集聚效应,形成北高南低的空间分布格局,热点区向南扩展,冷点区围绕西南部移动,呈“收缩—扩大—收缩”趋势。④将耕地利用划分为耕地利用生态先导区、均衡区、互补区和升级区4个区,制定区域差异化的耕地低碳利用措施。【结论】研究结果有利于东北三省耕地低碳利用和优化用地布局,以期为实现耕地可持续利用,推进耕地生态文明建设提供一定理论参考。 展开更多
关键词 耕地利用生态效率 分区 低碳 超效率SBM模型 两维图论聚类 东北三省
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基于数字报历史优秀版面的样式智能生成与微调
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作者 陶颖 程雨夏 +3 位作者 曾振宇 庄跃辉 张艺馨 何兴臻 《智能系统学报》 CSCD 北大核心 2024年第4期930-940,共11页
在传统报纸印刷行业中,设计人员需要根据设计规则进行人工排版,其排版过程造价成本较高且耗时耗力。为提高排版效率,研究提出一种基于历史优秀版面的样式自动生成与微调方法。为了从数据中学习到报纸排版的风格,创建一个包含丰富的设计... 在传统报纸印刷行业中,设计人员需要根据设计规则进行人工排版,其排版过程造价成本较高且耗时耗力。为提高排版效率,研究提出一种基于历史优秀版面的样式自动生成与微调方法。为了从数据中学习到报纸排版的风格,创建一个包含丰富的设计元素参数信息的电子报数据库,这些特征信息能够有效地反映报纸的布局。对于给定的新闻文章,首先根据历史优秀版面训练概率模型来推断电子报版面的样式,并结合固定约束和用户约束保证样式有效,同时构建美学设计原理的量化方法进一步实现样式微调。最后通过定性和定量评估,表明新方法可以生成满足视觉美观性、层次性和可读性的报纸。本文方法可为版面设计样式智能生成提供参考。 展开更多
关键词 布局自动化 图形设计 设计原理 图像数据库 数据驱动方法 概率分布 聚类 约束规划
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全媒体交互式演播室集群设计与实践
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作者 金亦建 《电视技术》 2024年第5期1-5,共5页
为节约成本,丽水市广播电视台在实施演播室高清化改造过程中,基于资源共享和集中控制管理理念,将6个独立的演播室改造建设为一个演播室集群,引入先进的图文系统丰富节目创作形态,融合新媒体内容,打造全媒体交互式演播室集群。文章重点... 为节约成本,丽水市广播电视台在实施演播室高清化改造过程中,基于资源共享和集中控制管理理念,将6个独立的演播室改造建设为一个演播室集群,引入先进的图文系统丰富节目创作形态,融合新媒体内容,打造全媒体交互式演播室集群。文章重点介绍该演播室的设计与建设情况。 展开更多
关键词 演播室集群 图文系统 集中控制 席位调度
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DPGL:The Direct3D9-based Parallel Graphics Library for Multi-display Environment 被引量:1
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作者 Zhen Liu Jiao-Ying Shi 《International Journal of Automation and computing》 EI 2007年第1期30-37,共8页
The emergence of high performance 3D graphics cards has opened the way to PC clusters for high performance multi- display environment. In order to exploit the rendering ability of PC clusters, we should design appropr... The emergence of high performance 3D graphics cards has opened the way to PC clusters for high performance multi- display environment. In order to exploit the rendering ability of PC clusters, we should design appropriate parallel rendering algorithms and parallel graphics library interfaces. Due to the rapid development of Direct3D, we bring forward DPGL, the Direct3D9-based parallel graphics library in D3DPR parallel rendering system, which implements Direct3D9 interfaces to support existing Direct3D9 application parallelization with no modification. Based on the parallelism analysis of Direct3D9 rendering pipeline, we briefly introduce D3DPR parallel rendering system. DPGL is the fundamental component of D3DPR. After presenting DPGL three layers architecture, we discuss the rendering resource interception and management. Finally, we describe the design and implementation of DPGL in detail, including rendering command interception layer, rendering command interpretation layer and rendering resource parallelization layer. 展开更多
关键词 Direct3D9-based parallel graphics library parallel rendering virtual environment PC clusters.
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Cluster Analysis on the Nucleotide Sequences of Six Genes in Rice 被引量:1
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作者 Jiqing YANG Shuo YANG 《Agricultural Biotechnology》 CAS 2014年第4期18-19,共2页
[ Objective] This study aimed to construct four-dimensional graphics of nucleotide sequences of six genes in rice ( GluB-6, GtuB-7, PDIL2, OsMPK1, OsCATC, OsCATA) and to conduct phase-space clustering, thus demonstr... [ Objective] This study aimed to construct four-dimensional graphics of nucleotide sequences of six genes in rice ( GluB-6, GtuB-7, PDIL2, OsMPK1, OsCATC, OsCATA) and to conduct phase-space clustering, thus demonstrating the relationship between the structure and function of rice genes. [ Method ] Base sequences were represented by four-dimensional graphics and clustered in the phase space. The relationship between clustering results and biological characteristics of these genes were analyzed. [ Result] Genes with similar four-dimensional graphics exhibit similar biological characteristics. [ Conclusion] Four-dimensional graphics of genes with different functions and base lengths present phase-space relationship with their biological functions, which provided an effective way for the prediction of gene function. 展开更多
关键词 Rice gene Four-dimensional graphics KM clustering Phase-space association
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Synthesis and Spectroscopic Study of a New Li-B-V-O Cluster Compound
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作者 HUANG Meng-meng GUO Bing-cui +4 位作者 HUANG Mei-qing LIN Hui-yun SHI Lin LIU Ting-yu CHEN Yi-ping 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2016年第S1期11-12,共2页
In this paper,the synthesis of a novel polyoxovanadiumborate[Li(H2O)3]3[V12B18O48(OH)12(OH)]·(H2O)5by hydrothermal method.FTIR,2DFTIR and UV-Vis absorption spectroscopy were employed to explore the relationships ... In this paper,the synthesis of a novel polyoxovanadiumborate[Li(H2O)3]3[V12B18O48(OH)12(OH)]·(H2O)5by hydrothermal method.FTIR,2DFTIR and UV-Vis absorption spectroscopy were employed to explore the relationships between structure and properties of 3-D compound 1. 展开更多
关键词 Polyoxovanadiumborate cluster Crystal-Structure two-dimensional Spectroscopy Hydrothermal synthesis
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Multi-relaxation-time lattice Boltzmann simulations of lid driven flows using graphics processing unit
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作者 Chenggong LI J.P.Y.MAA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2017年第5期707-722,共16页
Large eddy simulation (LES) using the Smagorinsky eddy viscosity model is added to the two-dimensional nine velocity components (D2Q9) lattice Boltzmann equation (LBE) with multi-relaxation-time (MRT) to simul... Large eddy simulation (LES) using the Smagorinsky eddy viscosity model is added to the two-dimensional nine velocity components (D2Q9) lattice Boltzmann equation (LBE) with multi-relaxation-time (MRT) to simulate incompressible turbulent cavity flows with the Reynolds numbers up to 1 × 10^7. To improve the computation efficiency of LBM on the numerical simulations of turbulent flows, the massively parallel computing power from a graphic processing unit (GPU) with a computing unified device architecture (CUDA) is introduced into the MRT-LBE-LES model. The model performs well, compared with the results from others, with an increase of 76 times in computation efficiency. It appears that the higher the Reynolds numbers is, the smaller the Smagorinsky constant should be, if the lattice number is fixed. Also, for a selected high Reynolds number and a selected proper Smagorinsky constant, there is a minimum requirement for the lattice number so that the Smagorinsky eddy viscosity will not be excessively large. 展开更多
关键词 large eddy simulation (LES) multi-relaxation-time (MRT) lattice Boltzmann equation (LBE) two-dimensional nine velocity components (D2Q9) Smagorinskymodel graphic processing unit (GPU) computing unified device architecture (CUDA)
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基于信息图形化的网页界面视觉均衡优化仿真
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作者 李馥颖 蒋强 《计算机仿真》 北大核心 2023年第7期195-199,共5页
为提高网页界面信息传递的生动性和直观性,提出基于信息图形化的网页界面视觉优化方法。结合界面信息传达和接收过程,将人性化、简洁化、创意化与普遍化等因素作为信息图形化准则;利用大数据聚类算法对界面数据作聚类处理,聚集相同特征... 为提高网页界面信息传递的生动性和直观性,提出基于信息图形化的网页界面视觉优化方法。结合界面信息传达和接收过程,将人性化、简洁化、创意化与普遍化等因素作为信息图形化准则;利用大数据聚类算法对界面数据作聚类处理,聚集相同特征的信息,明确信息主次,提高界面简洁度;分别从照度和反射两个分量完成界面图像平滑处理,提高对比度;通过颜色空间转换设计色彩增强函数,增强界面色彩,设定合理的亮度阈值,确保界面亮度更加舒适。仿真结果证明,优化后的界面运行负载更低,界面灰度值更加均衡,整体结构简洁,能够准确传达信息。 展开更多
关键词 信息图形化 网页界面 视觉优化 数据聚类 色彩增强
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基于两维图论聚类的矿粮复合区“三生”空间适宜性分区——以湖北省大冶市陈贵镇为例 被引量:1
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作者 宋复蓉 曾向阳 《资源与产业》 2023年第4期55-66,共12页
为了探究微观区域的“三生”空间适宜性分区,从而为乡镇一级的国土规划和全域土地整治规划提供参考,本文以属于矿粮复合区的湖北省大冶市陈贵镇为研究对象,从构建陈贵镇“三生”空间适宜性评价指标体系入手,运用两维图论聚类算法,对陈... 为了探究微观区域的“三生”空间适宜性分区,从而为乡镇一级的国土规划和全域土地整治规划提供参考,本文以属于矿粮复合区的湖北省大冶市陈贵镇为研究对象,从构建陈贵镇“三生”空间适宜性评价指标体系入手,运用两维图论聚类算法,对陈贵镇“三生”空间开展适宜性评价与分区研究。研究结果表明:1)陈贵镇镇域适宜的“三生”空间主要呈现为2大块状,1块围绕陈贵村呈零散分布,另1块主要聚集于天台山区;不适宜的“三生”空间主要分布在陈贵镇最南端及东北部,其余呈小斑块零散分布。2)从陈贵镇村域的“三生”空间适宜性来看,等级为适宜的村域,其生产空间、生活空间、生态空间都呈现出均衡性发展,已经接近生产空间集约高效、生活空间宜居适度、生态空间山清水秀的政府规划目标。3)矿业开采活动对陈贵镇“三生”空间适宜性的影响作用显著,不但严重影响生态空间,而且还对农业生产和非矿业生产均产生一定的负面影响作用,从而降低矿粮复合区的社会效益,并可能导致整体空间利用水平不高。4)本文利用两维图论聚类算法,基于适宜性评价结果,再结合实际的空间利用特征及城乡规划,将陈贵镇“三生”空间分为5个区域。Ⅰ区为农业生产核心区,该区域农业生产空间面积较大且较为聚集;Ⅱ区为乡镇发展主导区及生活空间核心区,引领着陈贵镇未来城乡一体化发展的方向;Ⅲ区为综合发展潜力区,空间存在着多种国土开发利用价值;Ⅳ区为生态重点保护区,需要着重协调工矿生产空间与生态空间的协调发展;Ⅴ区为生态农业旅游发展区,可利用生态农业带动生态旅游业的发展。 展开更多
关键词 两维图论聚类法 矿粮复合区 “三生”空间 适宜性分区
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Popularity Prediction of Social Media Post Using Tensor Factorization 被引量:1
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作者 Navdeep Bohra Vishal Bhatnagar +3 位作者 Amit Choudhary Savita Ahlawat Dinesh Sheoran Ashish Kumari 《Intelligent Automation & Soft Computing》 SCIE 2023年第4期205-221,共17页
The traditional method of doing business has been disrupted by socialmedia. In order to develop the enterprise, it is essential to forecast the level ofinteraction that a new post would receive from social media users... The traditional method of doing business has been disrupted by socialmedia. In order to develop the enterprise, it is essential to forecast the level ofinteraction that a new post would receive from social media users. It is possiblefor the user’s interest in any one social media post to be impacted by external factors or to dwindle as a result of changes in his behaviour. The popularity detectionstrategies that are user-based or population-based are unable to keep up with theseshifts, which leads to inaccurate forecasts. This work makes a prediction abouthow popular the post will be and addresses any anomalies caused by factors outside of the study. A novel improved PARAFAC (A-PARAFAC) method that istensor factorization-based has been presented in order to cope with the user criteria that will be used in the future to rate any project. We consolidated the information on the historically popular content, and we accelerated the computation bychoosing the top contents that were most like each other. The tensor is factorisedwith the application of the Adam optimization. It has been modified such that thebias is now included in the gradient function of A-PARAFAC, and the value ofthe bias is updated after each iteration. The prediction accuracy is improved by32.25% with this strategy compared to other state of the art methods. 展开更多
关键词 Tensor decomposition popularity prediction group level popularity graphical clustering PARAFAC
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基于RAPIDS的无参DBSCAN算法
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作者 卢建云 邵俊明 张蔚 《数据采集与处理》 CSCD 北大核心 2023年第2期426-438,共13页
具有噪声的基于密度的空间聚类(Density‑based spatial clustering of applications with noise,DBSCAN)能够发现不同密度和大小的类簇,对噪声也有很好的鲁棒性,被广泛地应用到数据挖掘的任务中。DBSCAN通常需要调整参数MinPts和Eps以... 具有噪声的基于密度的空间聚类(Density‑based spatial clustering of applications with noise,DBSCAN)能够发现不同密度和大小的类簇,对噪声也有很好的鲁棒性,被广泛地应用到数据挖掘的任务中。DBSCAN通常需要调整参数MinPts和Eps以达到更优的聚类效果,但往往在搜索最优参数的过程中会影响DBSCAN的性能。本文从两个方面优化DBSCAN,一方面,提出一种无参的方法优化DBSCAN全局参数选择。无参方法利用自然最近邻获得数据集的自然特征值,并将自然特征值作为参数MinPts值。然后,根据自然特征值计算自然特征集合,利用自然特征集合中的数据分布特性,分别采取统计最小值、平均值和最大值3种方式得到Eps值。另一方面,采用集成数据科学实时加速平台(Real‑time acceleration platform for integrated data science,RAPIDS)的图形处理器(Graphics processing unit,GPU)计算加快DBSCAN算法的收敛速度。实验结果表明,本文提出的方法在优化DBSCAN参数选择的同时,取得了与密度峰值聚类(Density peaks clustering,DPC)相当的聚类结果。 展开更多
关键词 集成数据科学实时加速平台 图形处理器 具有噪声的基于密度的空间聚类 自然最近邻 聚类
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基于图形拓扑的一键顺控技术在流域电站群集中控制中的应用 被引量:1
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作者 李玉琼 向文军 《四川水力发电》 2023年第2期108-112,共5页
随着大渡河公司流域电站的陆续建成投产,生产指挥中心管辖的电站增加到8站,调度业务环境日趋复杂化,传统的电话下令、手工拟定操作票等倒闸业务工作模式逐渐无法满足设备操作日益频繁的情况下,提出并设计基于图形拓扑的一键顺控操作系... 随着大渡河公司流域电站的陆续建成投产,生产指挥中心管辖的电站增加到8站,调度业务环境日趋复杂化,传统的电话下令、手工拟定操作票等倒闸业务工作模式逐渐无法满足设备操作日益频繁的情况下,提出并设计基于图形拓扑的一键顺控操作系统。从实践效果来看,该系统成票错误率低、操作效率高、安全性能强。 展开更多
关键词 图形拓扑 顺控 水电群 应用特点
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High-Performance Flow Classification of Big Data Using Hybrid CPU-GPU Clusters of Cloud Environments
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作者 Azam Fazel-Najafabadi Mahdi Abbasi +5 位作者 Hani H.Attar Ayman Amer Amir Taherkordi Azad Shokrollahi Mohammad R.Khosravi Ahmed A.Solyman 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2024年第4期1118-1137,共20页
The network switches in the data plane of Software Defined Networking (SDN) are empowered by an elementary process, in which enormous number of packets which resemble big volumes of data are classified into specific f... The network switches in the data plane of Software Defined Networking (SDN) are empowered by an elementary process, in which enormous number of packets which resemble big volumes of data are classified into specific flows by matching them against a set of dynamic rules. This basic process accelerates the processing of data, so that instead of processing singular packets repeatedly, corresponding actions are performed on corresponding flows of packets. In this paper, first, we address limitations on a typical packet classification algorithm like Tuple Space Search (TSS). Then, we present a set of different scenarios to parallelize it on different parallel processing platforms, including Graphics Processing Units (GPUs), clusters of Central Processing Units (CPUs), and hybrid clusters. Experimental results show that the hybrid cluster provides the best platform for parallelizing packet classification algorithms, which promises the average throughput rate of 4.2 Million packets per second (Mpps). That is, the hybrid cluster produced by the integration of Compute Unified Device Architecture (CUDA), Message Passing Interface (MPI), and OpenMP programming model could classify 0.24 million packets per second more than the GPU cluster scheme. Such a packet classifier satisfies the required processing speed in the programmable network systems that would be used to communicate big medical data. 展开更多
关键词 OPENMP Compute Unified Device Architecture(CUDA) Message Passing Interface(MPI) packet classification medical data tuple space algorithm graphics Processing Unit(GPU)cluster
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土地整理优先度评价方法及其应用研究 被引量:35
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作者 罗罡辉 吴次芳 徐保根 《浙江大学学报(农业与生命科学版)》 CAS CSCD 北大核心 2004年第3期347-352,共6页
将主成分分析与两维图论聚类分析有机结合,确立了土地整理优先度的评价方法,并将其应用于宁波市鄞州区土地整理的评价工作中,取得了良好的实际效果.
关键词 主成分分析 两维图论聚类 土地整理 优先度
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分层Dirichlet过程及其应用综述 被引量:40
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作者 周建英 王飞跃 曾大军 《自动化学报》 EI CSCD 北大核心 2011年第4期389-407,共19页
Dirichlet过程是一种应用于非参数贝叶斯模型中的随机过程,特别是作为先验分布应用在概率图模型中.与传统的参数模型相比,Dirichlet过程的应用更加广泛且模型更加灵活,特别是应用于聚类问题时,该过程能够自动确定聚类数目和生成聚类中... Dirichlet过程是一种应用于非参数贝叶斯模型中的随机过程,特别是作为先验分布应用在概率图模型中.与传统的参数模型相比,Dirichlet过程的应用更加广泛且模型更加灵活,特别是应用于聚类问题时,该过程能够自动确定聚类数目和生成聚类中心的分布参数.因此,近年来,在理论和应用上均得到了迅速的发展,引起越来越多的关注.本文首先介绍Dirichlet过程,而后描述了以Dirichlet过程为先验分布的Dirichlet过程混合模型及其应用,接着概述分层Dirichlet过程及其在相关算法构造中的应用,最后对分层Dirichlet过程的理论和应用进行了总结,并对未来的发展方向作了探讨. 展开更多
关键词 Dirichlet过程 概率图模型 聚类 分层Dirichlet过程
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基于图形处理器的数据流快速聚类 被引量:24
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作者 曹锋 周傲英 《软件学报》 EI CSCD 北大核心 2007年第2期291-302,共12页
在数据流环境下,聚类算法不仅需要有较高的聚类质量,同时需要有实时处理速度.因而,提出了一类基于图形处理器(graphics processing unit,简称GPU)的快速聚类方法,包括基于K-means的基本聚类方法、基于GPU的数据流聚类以及数据流簇进化... 在数据流环境下,聚类算法不仅需要有较高的聚类质量,同时需要有实时处理速度.因而,提出了一类基于图形处理器(graphics processing unit,简称GPU)的快速聚类方法,包括基于K-means的基本聚类方法、基于GPU的数据流聚类以及数据流簇进化分析方法.这些方法的共同特点是充分利用了GPU强大的处理能力和流水线特性.与以往具有独立框架的数据流聚类算法不同,这些基于GPU的聚类算法具有同一框架和多种聚类分析功能,为数据流聚类分析提供了统一的平台.从分析可知,数据流聚类分析的核心操作实际上就是距离计算和比较.基于这一认识,利用GPU的子素向量处理功能进行距离计算.性能验证实验是在配有Pentium IV3.4G CPU和NVIDIA GeForce 6800 GT显卡的PC上进行的.综合分析和实验结果表明,基于GPU的数据流聚类算法比传统的CPU算法平均快7倍,从而为高速数据流应用提供了良好的支持. 展开更多
关键词 数据流 聚类 图形处理器 进化 窗口
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原子团簇P_8的同分异构体预测 被引量:5
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作者 陈明旦 李基涛 +2 位作者 黄荣彬 郑兰荪 区泽棠 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 1999年第4期395-400,共6页
根据由激光产生的磷原子团簇正离子的质谱图所出现具有规律"奇幻数"的线索,即从开始质谱图的信号强度以8为周期变化,可以推断出从开始稳定的磷原子团簇正离子是以P8为结构单元依次聚合而生成的。使用分子图形软件设计出19... 根据由激光产生的磷原子团簇正离子的质谱图所出现具有规律"奇幻数"的线索,即从开始质谱图的信号强度以8为周期变化,可以推断出从开始稳定的磷原子团簇正离子是以P8为结构单元依次聚合而生成的。使用分子图形软件设计出19种P8的同分异构体,并进行分子力学、PM3半经验量子化学和ADF密度泛函优化.所有的模型中的磷原子均采用二配位和三配位成键.从各异构体成键能量的比较中可得知,笼状结构比平面结构稳定,平面环越大越不稳定,最稳定的P8构型是由12个单键组成的楔状结构.虽然目前还没有P8的实验数据,但在某些单质磷和含磷化合物中含有P8楔状结构单元.楔状结构的P8可认为是由2个很稳定正四面体P4分别断裂4个键后重新生成4个键而产生的. 展开更多
关键词 原子团族 同分异构体 P8 团族 磷原子团簇
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基于数据挖掘的海上交通流数据特征分析 被引量:20
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作者 郑滨 陈锦标 +1 位作者 夏少生 金永兴 《中国航海》 CSCD 北大核心 2009年第1期60-63,90,共5页
将基于数据挖掘的聚类分析和图形化属性分析方法引入海上交通流数据特性分析领域。阐述了数据挖掘的基本思想与方法,并着重介绍了使用开源数据挖掘工具WEKA对某海上航道的交通流数据进行的数据挖掘实验。实验综合使用聚类分析和图形化... 将基于数据挖掘的聚类分析和图形化属性分析方法引入海上交通流数据特性分析领域。阐述了数据挖掘的基本思想与方法,并着重介绍了使用开源数据挖掘工具WEKA对某海上航道的交通流数据进行的数据挖掘实验。实验综合使用聚类分析和图形化属性分析两种方法得到该航道的特性信息,其结果证明利用数据挖掘方法可得到有价值的交通特性信息,并能为海上交通的有效管理提供有力的决策依据。 展开更多
关键词 水路运输 海上交通流 数据挖掘 聚类分析 图形化属性分析 算法
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