共查询到16条相似文献,搜索用时 31 毫秒
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关联规则在肿瘤诊断中的应用 总被引:6,自引:0,他引:6
挖掘肿瘤诊断数据库中的关联规则,能为肿瘤诊断提供有用的信息。肿瘤诊断数据库中的属性常为数量型属性,因此如何将数量型属性离散化是挖掘关联规则的难点。竞争聚集算法综合了分层聚类与划分聚类的优点,它能够有效地体现数据的实际分布情况并得到优化的聚类个数,因此能将数量型属性离散化成若干个优化的区间。 相似文献
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讨论了区间值关系数据库上模糊关联规则的挖掘算法与预测方法。采用一种比RFCM算法省时的FCMdd算法将记录在属性的取值划分成若干个模糊集,并提出区间值关系数据库上模糊关联规则的挖掘算法。仿真实例说明挖掘算法能够通过挖掘有意义的模糊关联规则来发现区间值关系数据库中蕴涵的关联性。区间值关系数据库上模糊关联规则的预测方法改进了标准可加性模型,并通过遗传算法调整模糊关联规则中三角模糊数的参数来提高预测的精度。 相似文献
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针对网络安全态势评估过程中存在数据源单一、实时性不强、准确率不高的问题,提出一种基于改进关联规则算法(Apriori算法)的网络安全态势感知方法;通过对数据的分析,发现在网络中存在关于安全态势的关联规则;通过网络攻击影响熵值序列的分析,对关联规则进行分类为空间正常和异常空间,进而对关联规则进行聚类分析;根据聚类后的规则划分网络安全态势等级;将改进后的算法应用到网络安全态势感知当中,实验结果表明,该方法满足了网络安全危险预警和实时监控的要求;改进的算法用于安全态势感知是可行的、有效的。 相似文献
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通过分析连续型属性数据的特点和已有的关联规则挖掘算法,在定量描述的准确性和算法的高效性方面作了进一步研究,针对已有的通过结合最大一项集和隶属函数值去计算染色体的适应值的模糊遗传挖掘算法速度慢的问题,提出一种基于聚类的模糊遗传关联规则挖掘算法。该算法采用模糊遗传原理在交易数据中同时提取关联规则和隶属函数。同时,采用k-means聚类算法对种群中的染色体进行分类并且依据分类得到的信息和自身的信息评估每个染色体的适应性,从而降低了扫描数据库的次数,测试结果表明该算法速度快,准确度高。 相似文献
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Robust fuzzy clustering of relational data 总被引:1,自引:0,他引:1
Popular relational-data clustering algorithms, relational dual of fuzzy c-means (RFCM), non-Euclidean RFCM (NERFCM) (both by Hathaway et al), and FANNY (by Kaufman and Rousseeuw) are examined. A new algorithm, which is a generalization of FANNY, called the fuzzy relational data clustering (FRC) algorithm, is introduced, having an identical objective functional as RFCM. However, the FRC does not have the restriction of RFCM, which is that the relational data is derived from Euclidean distance as the measure of dissimilarity between the objects, and it also does not have limitations of FANNY, including the use of a fixed membership exponent, or a fuzzifier exponent, m. The FRC algorithm is further improved by incorporating the concept of Dave's object data noise clustering (NC) algorithm, done by proposing a concept of noise-dissimilarity. Next, based on the constrained minimization, which includes an inequality constraint for the memberships and corresponding Kuhn-Tucker conditions, a noise resistant, FRC algorithm is derived which works well for all types of non-Euclidean dissimilarity data. Thus it is shown that the extra computations for data expansion (/spl beta/-spread transformation) required by the NERFCM algorithm are not necessary. This new algorithm is called robust non-Euclidean fuzzy relational data clustering (robust-NE-FRC), and its robustness is demonstrated through several numerical examples. Advantages of this new algorithm are: faster convergence, robustness against outliers, and ability to handle all kinds of relational data, including non-Euclidean. The paper also presents a new and better interpretation of the noise-class. 相似文献
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用语言云模型发掘关联规则 总被引:55,自引:0,他引:55
该文提出用语言云模型用于KDD中知识表达和不确定性处理,引入了多维云模型作为一维模型的扩展.语言云的数字特征量将语言值的模糊性和随机性用统一的方式巧妙地综合到一起,基于云模型的概念层次结构可以跨越定量和定性知识之间的鸿沟.为了发现强关联规则,属性值要在较高的概念层上泛化,同时允许相邻属性值或语言项间有重叠.这种软划分可以模仿人类的思想,使发现的知识具有稳健性.将基于云模型的泛化方法与Apriori算法结合起来,从空间数据库中发掘关联规则.试验显示了其有效性、高效性和灵活性. 相似文献
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提出一种基于矩阵加权关联规则的空间粒度聚类算法。该算法核心思想是根据文档特征向量矩阵提取文档的相似度,再在该关联规则算法上进行聚类来寻找相似关系的频繁项集。通过引入核函数,样本点被非线性变换映射到高维特征空间进行聚类,提高聚类性能。通过矩阵加权关联规则算法进行聚类。通过实验表明,在处理中小型文档时,该算法的精确度优于传统Apriori算法和K-mean算法;在处理大型文档时,该算法的时间复杂度小于传统的K-mean算法。 相似文献
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传统K-means算法除了对初始聚类中心的选择非常敏感,易收敛到局部最优解外,还存在着K值难以确定的问题,不合适的K值往往会得到较差的聚类结果。而K值问题也是聚类分析中的一个重要的研究方向,在粒子群聚类算法的基础上,结合K-means算法,提出了自适应K值的粒子群聚类算法。当算法收敛时,可通过比较不同K值时全局最优适应度值之间的关系来决定K值的增大与减小。实验表明改进的算法可以有效指导K值的选取,并且具有较好的聚类效果。 相似文献
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Utilizing Genetic Algorithms to Optimize Membership Functions for Fuzzy Weighted Association Rules Mining 总被引:1,自引:2,他引:1
It is not an easy task to know a priori the most appropriate fuzzy sets that cover the domains of quantitative attributes
for fuzzy association rules mining. In general, it is unrealistic that experts can always provide such sets. And finding the
most appropriate fuzzy sets becomes a more complex problem when items are not considered to have equal importance and the
support and confidence parameters required for the association rules mining process are specified as linguistic terms. Existing
clustering based automated methods are not satisfactory because they do not consider the optimization of the discovered membership
functions. In order to tackle this problem, we propose Genetic Algorithms (GAs) based clustering method, which dynamically
adjusts the fuzzy sets to provide maximum profit based on user specified linguistic minimum support and confidence terms.
This is achieved by tuning the base values of the membership functions for each quantitative attribute with respect to two
different evaluation functions maximizing the number of large itemsets and the average of the confidence intervals of the
generated rules. To the best of our knowledge, this is the first effort in this direction. Experiments conducted on 100 K
transactions from the adult database of United States census in year 2000 demonstrate that the proposed clustering method
exhibits good performance in terms of the number of produced large itemsets and interesting association rules. 相似文献