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《振动工程学报》2019,(5)
针对旋转机械故障数据聚类分析中的初始聚类中心不确定和孤立点敏感问题,提出了一种集成多策略改进的模糊C均值(FCM)聚类方法。首先以故障数据集的决策属性为等价关系对数据集进行划分,得到若干个由等价关系导出的等价类;然后以每个等价类为可行域,采用均值漂移方法搜索故障数据类中心;最后以搜索到的类中心为FCM算法的初始聚类中心,通过核技术计算故障数据样本与相应类中心在高维特征空间中的欧氏距离,从而实现数据样本相似性的有效度量,并完成故障数据的模糊聚类。通过标准数据集和旋转机械故障数据集对方法的性能进行了验证及比较分析。结果显示,改进FCM算法的聚类性能相比传统FCM算法的聚类性能得到了明显提升,在收敛速度和聚类准确性两个性能指标上,改进的FCM算法比FCM算法具有显著优势。 相似文献
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K-means算法是一种常用的聚类算法,但是聚类中心的初始化是其中的一个难点。笔者提出了一个基于层次思想的初始化方法。一般聚类问题均可看作加权聚类,通过层层抽样减少数据量,然后采用自顶向下的方式,从抽样结束层到原始数据层,每层都进行聚类,其中每层初始聚类中心均通过对上层聚类中心进行换算得到,重复该过程直到原始数据层,可得原始数据层的初始聚类中心。模拟数据和真实数据的实验结果均显示基于层次抽样初始化的K-means算法不仅收敛速度快、聚类质量高,而且对噪声不敏感,其性能明显优于现有的相关算法。 相似文献
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周玮 《中国新技术新产品》2024,(2):134-136
本文对基于聚类算法的财务大数据智能分析处理技术进行了研究,旨在处理金融领域管理庞大的财务数据以及更好地应对不断增长的数据挑战。本文在设计财务大数据智能分析系统总架构的基础上,对系统软件部分进行了详细地分析设计。其中数据收集与预处理主要负责获取原始数据,同时确保收集数据的质量与一致性。特征工程提取主要为聚类算法提供有意义的特征,以更好地捕捉数据的模式和结构。聚类建模算法分析是系统的核心部分,其将财务数据划分为不同的簇,整理数据中的内在结构。数据可视化可将复杂的聚类结果以直观的方式呈现给用户。系统性能测试对测试结果进行研究,说明系统在财务大数据分析中具有有效性和可行性。 相似文献
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针对模糊C-均值聚类算法敏感于初始聚类中心及聚类收敛慢、聚类数目手动设定等缺陷,提出了基于改进蝙蝠优化自确定的模糊C-均值聚类算法。该算法是基于密度峰值综合衡量聚类中心外围数据密集程度和聚类中心间距离,自动确定聚类中心和聚类数目,以此作为改进蝙蝠算法的初始中心;在原始蝙蝠算法中引入Levy飞行特征加强算法跳出局部最优能力;使用Powell局部搜索加快算法的收敛,利用改进的蝙蝠种群进行种群寻优,并将最优蝙蝠位置作为聚类C-均值新聚类中心,进行模糊聚类,以此循环交叉迭代多次最终获得聚类结果。将基于改进蝙蝠优化自确定的模糊C-均值聚类算法与其它两种聚类算法在标准数据集上进行仿真对比,实验结果表明:与其它两种算法相比,该算法收敛速度快、误差率低。 相似文献
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在体绘制领域和图像分割中,数据集通常具有流形结构,各部分边界连接紧密且伴随局部噪声,给传统聚类算法的应用带来了较大的困难.本文根据非参数密度估计方法提出了一种基于多尺度信息融合的层次聚类算法.新算法通过整合密度差异和边界信息构造了一种多尺度结构信息融合的相似性度量,通过水平集的图连接策略推导出一种层次化的类结构剖析过程以获取稳定的聚类结果.新算法不受数据集形状、密度类型的限制,无需对数据集进行假设,可自动识别数据集常见的聚类结构特征.同时聚类结果较为稳定,算法对噪声具有较强的鲁棒性.从人工数据集和真实数据集以及应用试验的测试结果可以看出新算法的优越性能. 相似文献
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Hakan Ferhatosmanolu Divyakant Agrawal Ömer Eeciolu Amr El Abbadi 《Journal of Materials Science: Materials in Electronics》2005,15(11):75-101
It is desirable to design partitioning methods that minimize the I/O time incurred during query execution in spatial databases. This paper explores optimal partitioning for two-dimensional data for a class of queries and develops multi-disk allocation techniques that maximize the degree of I/O parallelism obtained in each case. We show that hexagonal partitioning has optimal I/O performance for circular queries among all partitioning methods that use convex non-overlapping regions. An analysis and extension of this result to all possible partitioning techniques is also given. For rectangular queries, we show that hexagonal partitioning has overall better I/O performance for a general class of range queries, except for rectilinear queries, in which case rectangular grid partitioning is superior. By using current algorithms for rectangular grid partitioning, parallel storage and retrieval algorithms for hexagonal partitioning can be constructed. Some of these results carry over to circular partitioning of the data—which is an example of a non-convex region. 相似文献
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采用EMPA,SEM和XRD等手段,研究低碳硅锰钢在双相区保温淬火(I&Q)、双相区保温+奥氏体化+盐浴配分(I&Q&P)和奥氏体化+盐浴配分(Q&P)工艺中的C,Mn元素配分行为及对残余奥氏体的综合作用。结果表明:经I&Q工艺处理后,得到马氏体、铁素体加少量残余奥氏体混合组织,C,Mn在马氏体中出现了富集,并且C富集程度高于Mn;经I&Q&P工艺处理后,C,Mn在板条马氏体中呈现不均匀分布,C的局部富集现象更明显,按C,Mn含量的不同,马氏体可分为"高C高Mn"、"高C低Mn"和"低C低Mn"3种;相比较Q&P工艺中只有C配分作用稳定残余奥氏体,I&Q&P工艺在C,Mn配分综合作用下,能得到更多的残余奥氏体。 相似文献
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Interface Migration between Martensite and Austenite during Quenching and Partitioning (Q&P) Process
An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning (Q&P) process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interface migration is excluded in constrained paraequilibrium (CPE) model. Based on "endpoint" predicted by CPE model the thermodynamic condition of interface migration is analyzed, that is, the difference in the chemical potential of iron in both ferrite (martenisite) and austenite produces the driving force of the iron atoms to migrate from one phase to the other phase. In addition, the interface migration can change the austenite fraction; as a result, the austenite fraction at partitioning temperature may be higher than that at quenching temperature through the interface migration, but this phenomenon cannot be explained by CPE model. 相似文献
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Interface Migration between Martensite and Austenite during Quenching and Partitioning (Q&P) Process
Ning ZHONG Xiaodong WANG Yonghua RONG Li WANG 《材料科学技术学报》2006,22(6):751-754
An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning (Q&P) process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interface migration is excluded in constrained paraequilibrium (CPE) model. Based on "endpoint" predicted by CPE model the thermodynamic condition of interface migration is analyzed, that is, the difference in the chemical potential of iron in both ferrite (martenisite) and austenite produces the driving force of the iron atoms to migrate from one phase to the other phase. In addition, the interface migration can change the austenite fraction; as a result, the austenite fraction at partitioning temperature may be higher than that at quenching temperature through the interface migration, but this phenomenon cannot be explained by CPE model. 相似文献
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José R. Herrero Juan J. Navarro 《Applicable Algebra in Engineering, Communication and Computing》2007,18(3):279-295
We present the way in which we have constructed an implementation of a sparse Cholesky factorization based on a hypermatrix
data structure. This data structure is a storage scheme which produces a recursive 2D partitioning of a sparse matrix. It
can be useful on some large sparse matrices. Subblocks are stored as dense matrices. Thus, efficient BLAS3 routines can be
used. However, since we are dealing with sparse matrices some zeros may be stored in those dense blocks. The overhead introduced
by the operations on zeros can become large and considerably degrade performance. We present the ways in which we deal with
this overhead. Using matrices from different areas (Interior Point Methods of linear programming and Finite Element Methods),
we evaluate our sequential in-core hypermatrix sparse Cholesky implementation. We compare its performance with several other
codes and analyze the results. In spite of using a simple fixed-size partitioning of the matrix our code obtains competitive
performance.
This work was supported by the Ministerio de Educación y Ciencia of Spain (TIN2004-07739-C02-01). 相似文献
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为提高对进入电石炉内电能的控制,引入“电石炉炉热指数”的概念.电石炉的炉热指数包含两部分:一部分是炉料配热系数 C ,代表炉内能量分配情况;一部分是高温区的热盈余 q ,代表炉内的热状态.通过对电石冶炼过程的分析,将电石炉分为炉料区和反应区,采用两段热平衡法计算电石炉的炉热指数,并对影响炉热指数的因素进行分析.通过对炉热指数的调节,达到对进入电石炉内电能的控制. 相似文献
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两相分配生物反应器——浊点系统在生物转化中的应用 总被引:4,自引:0,他引:4
利用两相分配生物反应器可以控制底物由非水相向水相释放,增加底物的溶解度和解除底物对微生物的抑制,保护产物降解,降低下游分离费用;论述了两相分配生物反应器的基本原理和发展概况,并以胆固醇边链切除生物转化为例,介绍了新开发的浊点系统两相分配生物反应器的巨大潜力。 相似文献