共查询到19条相似文献,搜索用时 156 毫秒
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学习矢量量化(LVQ)聚类算法存在严重的对初值敏感的问题,若初值的选择偏差太大,就不会产生好的聚类效果,致使聚类精准度不够。免疫克隆算法具有很强的群体搜索能力,将免疫克隆算法用于优化LVQ聚类算法的初值,并将改进得到的聚类算法用于对IRIS数据集进行分类。分类结果与标准的LVQ算法的比较表明,改进后的聚类算法在稳定性上有了较大幅度的提高。 相似文献
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无监督学习矢量量化(LVQ)是一类基于最小化风险函数的聚类方法,文中通过对无监督LVQ风险函数的研究,提出了无监督LVQ算法的广义形式,在此基础上将当前典型的LVQ算法表示为基于不同尺度函数的LVQ算法,极大地方便了学习矢量量化神经网络的推广与应用。通过对无监督LVQ神经网络的改造,得到了基于无监督聚类算法的有监督LVQ神经网络,并将其应用于说话人辨认,取得了满意的结果并比较了几种典型聚类算法的优劣。 相似文献
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对于时间序列的基因表达数据,传统的聚类算法都是以距离为相似性度量标准,没有考虑基因随时间变化的相似趋势。从基因变化的趋势出发,构造了一种新的模糊相似关系矩阵,提出了改进的基于模糊相似关系的聚类算法,并以该算法计算FCM的初始聚类中心。将该方法应用在酵母菌基因表达数据中,实验结果表明该算法不仅克服了FCM算法易陷入局部极小值、对初值敏感的缺点,而且能够发现一些表达模式变化趋势相似的共调控基因。 相似文献
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基于粒子群优化的改进模糊聚类图像分割算法将微粒群搜索聚类中心作为图像分割的聚类初值,克服了FCM分割算法对聚类中心初值敏感的缺点,大幅提高了图像分割算法的计算速度。改进的模糊聚类图像分割算法,一方面考虑到像素的空间位置信息和相互邻域之间像素有很大的相关性,在目标函数中引入邻域惩罚函数;另一方面提出聚类在二维方向上进行更新的思想,建立了包含邻域单元熵的新聚类目标函数。实验结果表明,该方法可以使模糊聚类的速度得到明显提高,对初始聚类中心不敏感,抗噪能力强,是一种有效的模糊聚类图像分割方法。 相似文献
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基于K-means的文本聚类算法① 总被引:4,自引:0,他引:4
针对K—means算法容易收敛到局部最优以及对初值的依赖性,基于多次采样一次预聚类搜索初始聚类中心的思想,提出了一种改进的K—means文本聚类方法。实验结果表明,改进的算法较原算法在准确率上有较大提高,并且具有更好的稳定性。 相似文献
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谱聚类作为一种新颖的聚类算法近年来受到模式识别领域的广泛关注。针对传统谱聚类算法对初始中心敏感的特点,通过引入对初值不敏感的k-调和平均算法,提出一种初始化独立的谱聚类算法。在人工数据和真实数据上的实验表明,相比于传统的k-means算法、FCM算法和EM算法,改进算法在稳定性和聚类性能上有了显著的提高。 相似文献
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Repairs to GLVQ: a new family of competitive learning schemes 总被引:2,自引:0,他引:2
Karayiannis N.B. Bezdek J.C. Pal N.R. Hathaway R.J. Pin-I Pai 《Neural Networks, IEEE Transactions on》1996,7(5):1062-1071
First, we identify an algorithmic defect of the generalized learning vector quantization (GLVQ) scheme that causes it to behave erratically for a certain scaling of the input data. We show that GLVQ can behave incorrectly because its learning rates are reciprocally dependent on the sum of squares of distances from an input vector to the node weight vectors. Finally, we propose a new family of models-the GLVQ-F family-that remedies the problem. We derive competitive learning algorithms for each member of the GLVQ-F model and prove that they are invariant to all scalings of the data. We show that GLVQ-F offers a wide range of learning models since it reduces to LVQ as its weighting exponent (a parameter of the algorithm) approaches one from above. As this parameter increases, GLVQ-F then transitions to a model in which either all nodes may be excited according to their (inverse) distances from an input or in which the winner is excited while losers are penalized. And as this parameter increases without limit, GLVQ-F updates all nodes equally. We illustrate the failure of GLVQ and success of GLVQ-F with the IRIS data. 相似文献
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A.K. Qin 《Pattern recognition》2005,38(5):773-776
A learning vector quantization (LVQ) algorithm called harmonic to minimum LVQ algorithm (H2M-LVQ)1 is presented to tackle the initialization sensitiveness problem associated with the original generalized LVQ (GLVQ) algorithm. Experimental results show superior performance of the H2M-LVQ algorithm over the GLVQ and one of its variants on several datasets. 相似文献
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《自动化学报》1999,25(5):1
In this paper, the performance of GLVQ-F algorithm of
GLVQ network is theoretically analyzed. The GLVQF algorithm, to some extent, has overcome
the shortcomings that GLVQ algorithm possesses. But, there are some problems in GLVQF
algorithm, for example, the algorithm has good performance on the winning prototype, and
on other prototypes, its performance is very unstable. In this paper, the reasons of the
problem are discussed. The rules of choosing the learning rates are proposed, and two
modified algorithms are developed therefrom. Finally, the performance of the modified
algorithms is verified with IRIS data, which shows the modified algorithms are more stable
and effective than GLVQF algorithm. 相似文献
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学习向量量化(LVQ)和泛化学习向量量化(GLVQ)算法都是采用欧氏距离作为相似性度量函数, 忽视了向量各维属性的数据取值范围,从而不能区分各维属性在分类中的不同作用。针对该问题,使用一种面向特征取值范围的向量相似性度量函数,对GLVQ进行改进,提出了GLVQ-FR算法。使用视频车型分类数据进行改进型GLVQ和LVQ2.1、GLVQ、GRLVQ、GMLVQ等算法的对比实验,结果表明:GLVQ-FR算法在车型分类中具有较高的分类准确性、运算速度和真实生产环境中的可用性。 相似文献
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The utilisation of clustering algorithms based on the optimisation of prototypes in neural networks is demonstrated for unsupervised learning. Stimulated by common clustering methods of this type (learning vector quantisation [LVQ, GLVQ] and K-means) a globally operating algorithm was developed to cope with known shortcomings of existing tools. This algorithm and K-means (for the common methods) were applied to the problem of clustering EEG patterns being pre-processed. It can be shown that the algorithm based on global random optimisation may find an optimal solution repeatedly, whereas K-means provides different sub-optimal solutions with respect to the quality measure defined as objective function. The results are presented. The performance of the algorithms is discussed. 相似文献
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Abderrahmane Boubezoul Sébastien Paris Mustapha Ouladsine 《Pattern recognition》2008,41(10):3173-3178
This paper discusses an alternative approach to parameter optimization of well-known prototype-based learning algorithms (minimizing an objective function via gradient search). The proposed approach considers a stochastic optimization called the cross entropy method (CE method). The CE method is used to tackle efficiently the initialization sensitiveness problem associated with the original generalized learning vector quantization (GLVQ) algorithm and its variants. Results presented in this paper indicate that the CE method can be successfully applied to this kind of problem on real-world data sets. As far as known by the authors, it is the first use of the CE method in prototype-based learning. 相似文献
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提出了一种解决位置管理问题的差分进化算法,给出了一种将采用浮点编码的种群个体映射为问题解的方法、基于问题特性的种群初始化启发式方法,以及早熟收敛问题的解决策略.基于随机生成的数据对算法进行了模拟实验,将该算法的结果与遗传算法、禁忌搜索算法及蚁群算法进行了对比. 相似文献