共查询到18条相似文献,搜索用时 203 毫秒
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蒋桂莲 《计算机与数字工程》2010,38(6):138-141
人脸识别方法易受光照、姿态和表情变化的影响,针对这一问题,提出了一种基于Gabor小波和粗糙集属性约简的人脸识别方法。该方法先对人脸图像进行Gabor小波变换,将小波变换的系数作为人脸图像的特征向量;然后结合信息论中信息熵与互信息的概念定义了粗糙集里的一种新的属性重要度,并以此属性重要度为启发式信息进行约简数据集,从而对所得的人脸图像特征进行降维,并采用支持向量机进行分类。实验结果表明,该算法降低了支持向量机分类器的复杂度,有较好的识别性能。 相似文献
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为解决取得特征向量维数过高问题,提出了一种改进的粗糙集属性约简算法。运用几何特征点方法得到人脸表情的局部特征向量,引入粗糙集理论,用改进的属性约简算法对提取到的表情特征进行优化选择,去掉冗余特征和对表情分类无用的不相关信息。实验结果显示,该方法不仅实现方便,识别率高,识别所用的时间也大大减少,充分表明了该方法的有效性。 相似文献
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针对基于粗糙集的大部分多标记特征选择方法存在的忽略样本的模糊性和邻域关系、手动设置邻域半径、从单一的样本空间度量属性重要度等问题,文中利用模糊邻域粗糙集弥补经典粗糙集的不足,并在此基础上从特征空间和标记空间出发,提出基于双空间模糊邻域相似关系的多标记特征选择算法.首先,设计自适应邻域半径的计算方法,构建特征空间下样本的模糊邻域相似矩阵.再根据模糊邻域相似关系,得出特征空间下的样本相似度及标记空间下的样本相似度.然后,通过权重将特征空间和标记空间上的样本相似度进行融合,基于融合后的度量计算属性重要度.最后,运用前向贪心算法构建多标记特征选择算法.在12个多标记数据集上的对比实验验证文中算法的有效性. 相似文献
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基于属性分布相似度的超图高维聚类算法研究 总被引:4,自引:0,他引:4
在许多聚类应用中,数据对象是具有高维、稀疏、二元的特征。传统聚类算法无法有效地处理此类数据。该文提出一种基于超图模型的高维聚类算法,通过定义对象属性分布特征向量和对象间属性分布相似度,建立超图模型,并应用超图分割法进行聚类。聚类结果通过簇内奇异特征值进行评价。实验结果和算法分析表明,该算法可以有效地进行聚类知识挖掘。 相似文献
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在属性一致度的概念和性质基础之上,提出一种基于属性一致度的属性约简算法。利用一致度构造属性间模糊相似矩阵,并用模糊聚类分析方法对属性重要性作了分类,从而得到动态属性分类图,得到了与粗糙集属性约简方法完全一致的结果。最后,用实例表明算法的有效性。 相似文献
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自动文本分类的效果在很大程度上依赖于属性特征的选择。针对传统基于频率阈值过滤的特征选择方法会导致有效信息丢失,影响分类精度的不足,提出了一种基于粗糙集的文本自动分类算法。该方法对加权后的特征属性进行离散化,建立一个决策表;根据基于依赖度的属性重要度对决策表中条件属性进行适当的筛选;采用基于条件信息熵的启发式算法实现文本属性特征的约简。实验结果表明,该方法能约简大量冗余的特征属性,在不降低分类精度的同时,提高文本分类的运行效率。 相似文献
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Attribute selection is one of the important problems encountered in pattern recognition, machine learning, data mining, and bioinformatics. It refers to the problem of selecting those input attributes or features that are most effective to predict the sample categories. In this regard, rough set theory has been shown to be successful for selecting relevant and nonredundant attributes from a given data set. However, the classical rough sets are unable to handle real valued noisy features. This problem can be addressed by the fuzzy-rough sets, which are the generalization of classical rough sets. A feature selection method is presented here based on fuzzy-rough sets by maximizing both relevance and significance of the selected features. This paper also presents different feature evaluation criteria such as dependency, relevance, redundancy, and significance for attribute selection task using fuzzy-rough sets. The performance of different rough set models is compared with that of some existing feature evaluation indices based on the predictive accuracy of nearest neighbor rule, support vector machine, and decision tree. The effectiveness of the fuzzy-rough set based attribute selection method, along with a comparison with existing feature evaluation indices and different rough set models, is demonstrated on a set of benchmark and microarray gene expression data sets. 相似文献
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在多标记学习中,数据降维是一项重要且具有挑战性的任务,而特征选择又是一种高效的数据降维技术。在邻域粗糙集理论的基础上提出一种多标记专属特征选择方法,该方法从理论上确保了所得到的专属特征与相应标记具有较强的相关性,进而改善了约简效果。首先,该方法运用粗糙集理论的约简算法来减少冗余属性,在保持分类能力不变的情况下获得标记的专属特征;然后,在邻域精确度和邻域粗糙度概念的基础上,重新定义了基于邻域粗糙集的依赖度与重要度的计算方法,探讨了该模型的相关性质;最后,构建了一种基于邻域粗糙集的多标记专属特征选择模型,实现了多标记分类任务的特征选择算法。在多个公开的数据集上进行仿真实验,结果表明了该算法是有效的。 相似文献
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针对当前基于属性重要性的决策表属性集分解方法存在的不足,提出了一种新型的基于决策分类的决策表属性集分解方法。分析了近似分类质量和属性重要性与决策分类之间的关系,利用粗糙集理论,从提高子决策表中决策分类正确性的角度出发考虑条件属性与决策属性之间的关系,提出了决策表分解的条件属性选择量度并对决策表实施属性集分解。 相似文献
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Rough set feature selection and rule induction for prediction of malignancy degree in brain glioma 总被引:1,自引:0,他引:1
The degree of malignancy in brain glioma is assessed based on magnetic resonance imaging (MRI) findings and clinical data before operation. These data contain irrelevant features, while uncertainties and missing values also exist. Rough set theory can deal with vagueness and uncertainty in data analysis, and can efficiently remove redundant information. In this paper, a rough set method is applied to predict the degree of malignancy. As feature selection can improve the classification accuracy effectively, rough set feature selection algorithms are employed to select features. The selected feature subsets are used to generate decision rules for the classification task. A rough set attribute reduction algorithm that employs a search method based on particle swarm optimization (PSO) is proposed in this paper and compared with other rough set reduction algorithms. Experimental results show that reducts found by the proposed algorithm are more efficient and can generate decision rules with better classification performance. The rough set rule-based method can achieve higher classification accuracy than other intelligent analysis methods such as neural networks, decision trees and a fuzzy rule extraction algorithm based on Fuzzy Min-Max Neural Networks (FRE-FMMNN). Moreover, the decision rules induced by rough set rule induction algorithm can reveal regular and interpretable patterns of the relations between glioma MRI features and the degree of malignancy, which are helpful for medical experts. 相似文献
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Yuhua Qian Author Vitae Jiye Liang Author Vitae Witold Pedrycz Author Vitae 《Pattern recognition》2011,44(8):1658-1670
Feature selection (attribute reduction) from large-scale incomplete data is a challenging problem in areas such as pattern recognition, machine learning and data mining. In rough set theory, feature selection from incomplete data aims to retain the discriminatory power of original features. To address this issue, many feature selection algorithms have been proposed, however, these algorithms are often computationally time-consuming. To overcome this shortcoming, we introduce in this paper a theoretic framework based on rough set theory, which is called positive approximation and can be used to accelerate a heuristic process for feature selection from incomplete data. As an application of the proposed accelerator, a general feature selection algorithm is designed. By integrating the accelerator into a heuristic algorithm, we obtain several modified representative heuristic feature selection algorithms in rough set theory. Experiments show that these modified algorithms outperform their original counterparts. It is worth noting that the performance of the modified algorithms becomes more visible when dealing with larger data sets. 相似文献
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Feature selection is a challenging problem in areas such as pattern recognition, machine learning and data mining. Considering a consistency measure introduced in rough set theory, the problem of feature selection, also called attribute reduction, aims to retain the discriminatory power of original features. Many heuristic attribute reduction algorithms have been proposed however, quite often, these methods are computationally time-consuming. To overcome this shortcoming, we introduce a theoretic framework based on rough set theory, called positive approximation, which can be used to accelerate a heuristic process of attribute reduction. Based on the proposed accelerator, a general attribute reduction algorithm is designed. Through the use of the accelerator, several representative heuristic attribute reduction algorithms in rough set theory have been enhanced. Note that each of the modified algorithms can choose the same attribute reduct as its original version, and hence possesses the same classification accuracy. Experiments show that these modified algorithms outperform their original counterparts. It is worth noting that the performance of the modified algorithms becomes more visible when dealing with larger data sets. 相似文献