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一种改进的k-means算法 总被引:5,自引:0,他引:5
k-means(k均值)算法是聚类方法中常用的一种划分方法.该算法适合对海量数据进行聚类,对球状、凸形分布的数据具有很好的聚类效果,但该算法有其突出的局限性,少量的孤立点就会对聚类结果产生很大的影响,因此,采用聚类均值点与聚类种子相分离的思想,给出了基于该思想的对k均值算法的改进算法.实验表明,该改进算法比原k均值算法具有更高的准确性. 相似文献
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Cuiling Chen;Zhi Li; 《Expert Systems》2024,41(12):e13720
Multiple kernel k-means clustering (MKKC) can efficiently incorporate multiple base kernels to generate an optimal kernel. Many existing MKKC methods all need two-step operation: learning clustering indicator matrix and performing clustering on it. However, the optimal clustering results of two steps are not equivalent to those of original problem. To address this issue, in this paper we propose a novel method named one-step multiple kernel k-means clustering based on block diagonal representation (OS-MKKC-BD). By imposing a block diagonal constraint on the product of indicator matrix and its transpose, this method can encourage the indicator matrix to be block diagonal. Then the indicator matrix can produce explicit clustering indicator, so as to implement one-step clustering, which avoids the disadvantage of two-step operation. Furthermore, a simple kernel weighting strategy is used to obtain an optimal kernel, which boosts the quality of optimal kernel. In addition, a three-step iterative algorithm is designed to solve the corresponding optimization problem, where the Riemann conjugate gradient iterative method is used to solve the optimization problem of the indicator matrix. Finally, by extensive experiments on eleven real data sets and comparison of clustering results with 10 MKC methods, it is concluded that OS-MKKC-BD is effective. 相似文献
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Süreyya Özöğür-Akyüz Buse Çisil Otar Pınar Karadayı Atas 《Computational Intelligence》2020,36(1):297-319
Ensemble learning is the process of aggregating the decisions of different learners/models. Fundamentally, the performance of the ensemble relies on the degree of accuracy in individual learner predictions and the degree of diversity among the learners. The trade-off between accuracy and diversity within the ensemble needs to be optimized to provide the best grouping of learners as it relates to their performance. In this optimization theory article, we propose a novel ensemble selection algorithm which, focusing specifically on clustering problems, selects the optimal subset of the ensemble that has both accurate and diverse models. Those ensemble selection algorithms work for a given number of the best learners within the subset prior to their selection. The cardinality of a subset of the ensemble changes the prediction accuracy. The proposed algorithm in this study determines both the number of best learners and also the best ones. We compared our prediction results to recent ensemble clustering selection algorithms by the number of cardinalities and best predictions, finding better and approximated results to the optimum solutions. 相似文献
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现有的k-均值聚类算法大都是以距离差异为基础的,而同等重要地依赖所有属性的相似性度量会引起误导.传统的k-均值算法选择的相似性度量通常是欧几里德距离的倒数,这种距离通常涉及所有的特征.而在距离公式中引入一些特征权值后,其聚类结果将依赖于这些权值,从而可以通过调整这些权值优化聚类效果.由于k-均值算法是迭代算法,很难直接确定其权值以优化聚类结果,因此提出了一种通过免疫算法学习权值的方法以改进聚类结果.实验结果显示,该方法确定的权重值在提高聚类效果方面是可行的、有效的. 相似文献
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Sentiment analysis for social media and online document has been a burgeoning area in text mining for the last decade. However, Email sentiment analysis has not been studied and examined thoroughly even though it is one of the most ubiquitous means of communication. In this research, a hybrid sentiment analysis framework for Email data using term frequency-inverse document frequency term weighting model for feature extraction, and k-means labeling combined with support vector machine classifier for sentiment classification is proposed. Empirical results indicate comparatively better classification results with the proposed framework than other combinations. 相似文献
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经典谱聚类算法将数据聚类转为图划分问题,在分析其Normalized Cut函数与传统加权核k-means等价基础上,设计了一种基于抽样改进加权核k-means算法的大规模数据集谱聚类算法,算法通过加权核k-means迭代优化避免Laplacian矩阵特征分解的大量资源占用,通过随机映射得到近似奇异值分解,并由近似奇异... 相似文献
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Web数据挖掘已经成为数据挖掘研究领域的热点,尤其是在电子商务网站的设计和使用中.文章阐述了在电子商务中如何运用Web数据挖掘技术,为企业更有效地确认目标市场、改进决策、获得更大的竞争优势提供帮助,并提出了一种Web数据挖掘系统的设计方案和实现方式.同时,对k-means聚类算法进行了优劣分析,并提出通过改变初始聚类中心的选取规则来提高算法的运行效率以及计算结果的准确度. 相似文献
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