一种区间型数据的自适应模糊c均值聚类算法

针对区间型数据的聚类问题,提出一种自适应模糊c均值聚类算法。该算法一方面基于区间数的中点和半宽度,通过引入区间宽度的影响因子以控制区间大小对聚类结果的影响;另一方面通过引入一个自适应系数,以减少区间型数据的数据结构对聚类效果的影响。通过仿真数据和Fish真实数据验证了该算法的有效性,并对聚类结果进行比较和分析。     

区间型数据的可能性聚类算法

针对区间型数据的模糊c均值聚类(IFCM)算法在实际应用中的不足,将可能性理论引入区间型数据的聚类问题,通过放松样本隶属度的约束条件和修正IFCM算法的目标函数,提出一种区间型数据的可能性聚类算法。通过仿真模拟实验和平均CR指标分析,结果表明:在包含噪声和孤立点等代表性比较差的样本数据的聚类问题中,该算法明显优于IFCM算法,能有效地降低噪声对聚类效果的影响。     

新型区间数据模糊C-均值聚类算法

在传统模糊C-均值聚类算法的基础上,提出了一种新型区间值数据模糊聚类算法。运用区间分割策略改进了区间距离的计算公式,成功解决了区间距离计算方法存在的缺陷。提出了区间值数据模糊聚类的数学模型,并拓广模糊C-均值算法对区间值数据进行聚类。仿真验证了所提出算法的有效性。     

基于属性权重区间监督的模糊C均值聚类算法

在加权模糊聚类算法中,属性权重确定的合理性是一个重要问题.鉴于用区间数描述决策者推理模糊性的优越性,提出属性权重用区间数表示,由区间层次分析法获得属性对聚类的贡献度,并以该区间为约束条件,提出了可同时获得属性权重和聚类结果的模糊C均值聚类新算法.实验结果表明,该算法以决策者的经验和偏好为监督,可避免迭代计算陷入不必要的局部极小解,能够提高权重分配的合理性,进而得到了更为准确的聚类结果.     

区间型数据的模糊c均值聚类算法

提取区间型数据的特征值,给出适用于区间型数据模糊聚类的FCM算法族(IFCM)。该算法适用于不同特征样本数据的模糊聚类运算,并可对聚类结果进行优化。聚类效果的仿真比较表明,IFCM聚类的平均失真度比基于欧氏距离的FCM聚类算法低6.81%。由于距离定义的合理性,IFCM可以根据区间型数据的不同特点调整特征值的聚类权重,并推广至多维类型数据的模糊聚类。     

IFCM:改进的区间值数据的模糊C-均值聚类算法

对基于区间值数据的模糊聚类算法进行了研究,介绍了具有控制区间大小对聚类结果影响的加权因子的模糊C-均值聚类新算法.针对区间值数据模糊C-均值聚类新算法提出了一个适应距离的弹性系数,使算法得到改进,既能利用传统的FCM算法,又考虑了区间大小对聚类结果的影响,同时也能发现不规则的聚类子集,使聚类结果更加准确.     

基于区间2-型模糊度量的粗糙K-means聚类算法*

现有粗糙K-means聚类算法及系列改进、衍生算法均是从不同角度描述交叉类簇边界区域中的不确定性数据对象,却忽视类簇间规模的不均衡对聚类迭代过程及结果的影响.文中引入区间2-型模糊集的概念度量类簇的边界区域数据对象,提出基于区间2-型模糊度量的粗糙K-means聚类算法.首先根据类簇的数据分布生成边界区域样本对交叉类簇的隶属度区间,体现数据样本的空间分布信息.然后进一步考虑类簇的数据样本规模,在隶属度区间的基础上自适应地调整边界区域的样本对交叉类簇的影响系数.文中算法削弱边界区域对较小规模类簇的中心均值迭代的不利影响,提高聚类精度.在人工数据集及UCI标准数据集的测试分析验证算法的有效性.     

增强型区间二型FCM算法

不确定性存在于图像处理、模式识别等众多领域的实际应用中, 模糊?? 均值聚类(FCM) 算法虽广泛应用于这些领域, 但其处理不确定性的能力较差. 引入区间二型模糊理论能有效提升算法处理不确定性的能力, 但相应地造成算法复杂度增加, 制约了区间二型FCM算法的推广应用. 鉴于此, 提出增强型区间二型FCM算法, 通过优化初始聚类中心和降型运算, 极大地减少了区间二型FCM算法的运算量, 并提升算法的收敛速度. 通过对随机和实际数据的实验比较验证了改进算法的有效性.

     

数据挖掘中区间数据模糊聚类研究——基于Wasserstein测度

针对目前区间数据模糊聚类研究中区间距离定义存在的局限性,引入能够考虑区间数值分布特征的Wasserstein距离测度,提出基于Wasserstein距离测度的单指标和双指标自适应模糊聚类算法及迭代模型。通过仿真实验和CR指数,证实了该类模型的优势。该算法在海量、堆积如山的数据挖掘中有着重要的实践意义。     

基于区间直觉模糊集的C均值聚类算法

针对区间直觉模糊集(IVIFS)的聚类问题,提出了基于IVIFS的C均值聚类算法.算法首先应用IVIFS的欧氏距离,构造了聚类的目标函数;然后根据拉格朗日乘数法推导出聚类的迭代公式,得到IVIFS聚类算法;此外,还提出一种IVIFS聚类的有效性函数,并将此函数和聚类结合,给出可以确定最佳聚类类别数的聚类流程;最后通过实...     

Clustering interval data through kernel-induced feature space

Recently, kernel-based clustering in feature space has shown to perform better than conventional clustering methods in unsupervised classification. In this paper, a partitioning clustering method in kernel-induce feature space for symbolic interval-valued data is introduced. The distance between an item and its prototype in feature space is expanded using a two-component mixture kernel to handle intervals. Moreover, tools for the partition and cluster interpretation of interval-valued data in feature space are also presented. To show the effectiveness of the proposed method, experiments with real and synthetic interval data sets were performed and a study comparing the proposed method with different clustering algorithms of the literature is also presented. The clustering quality furnished by the methods is measured by an external cluster validity index (corrected Rand index). These experiments showed the usefulness of the kernel K-means method for interval-valued data and the merit of the partition and cluster interpretation tools.     

区间值属性数据集关联规则挖掘算法仿真

对区间值属性数据集进行挖掘,可以有效分析出数据之间的关系。针对现有数据挖掘方法未对大规模数据进行聚类,导致挖掘过程占据内存大,挖掘精度低的问题,提出了一种新的区间值属性数据集挖掘算法。对问题定义、数据准备、数据提取、模式预测和数据聚类等模块进行详细分析,完成区间值属性数据聚类。根据聚类结果,将区间值属性数据分成多个数据集,挑选出能够支持最小支持度的项目集,将这些项目集作为频繁项集,进而提取出数据集之间的关联规则,将关联规则融入数据计算步骤,完成数据挖掘。为验证算法效果,进行仿真,结果表明,相较于传统挖掘算法,所提挖掘算法占用容量更小,挖掘精度更高。     

Uncertain Fuzzy Clustering: Interval Type-2 Fuzzy Approach to C-Means

In many pattern recognition applications, it may be impossible in most cases to obtain perfect knowledge or information for a given pattern set. Uncertain information can create imperfect expressions for pattern sets in various pattern recognition algorithms. Therefore, various types of uncertainty may be taken into account when performing several pattern recognition methods. When one performs clustering with fuzzy sets, fuzzy membership values express assignment availability of patterns for clusters. However, when one assigns fuzzy memberships to a pattern set, imperfect information for a pattern set involves uncertainty which exist in the various parameters that are used in fuzzy membership assignment. When one encounters fuzzy clustering, fuzzy membership design includes various uncertainties (e.g., distance measure, fuzzifier, prototypes, etc.). In this paper, we focus on the uncertainty associated with the fuzzifier parameter m that controls the amount of fuzziness of the final C-partition in the fuzzy C-means (FCM) algorithm. To design and manage uncertainty for fuzzifier m, we extend a pattern set to interval type-2 fuzzy sets using two fuzzifiers m₁ and m₂ which creates a footprint of uncertainty (FOU) for the fuzzifier m. Then, we incorporate this interval type-2 fuzzy set into FCM to observe the effect of managing uncertainty from the two fuzzifiers. We also provide some solutions to type-reduction and defuzzification (i.e., cluster center updating and hard-partitioning) in FCM. Several experimental results are given to show the validity of our method     

Adaptive fuzzy c-means clustering algorithm for interval data type based on interval-dividing technique

Clustering for symbolic data type is a necessary process in many scientific disciplines, and the fuzzy c-means clustering for interval data type (IFCM) is one of the most popular algorithms. This paper presents an adaptive fuzzy c-means clustering algorithm for interval-valued data based on interval-dividing technique. This method gives a fuzzy partition and a prototype for each fuzzy cluster by optimizing an objective function. And the adaptive distance between the pattern and its cluster center varies with each algorithm iteration and may be either different from one cluster to another or the same for all clusters. The novel part of this approach is that it takes into account every point in both intervals when computing the distance between the cluster and its representative. Experiments are conducted on synthetic data sets and a real data set. To compare the comprehensive performance of the proposed method with other four existing methods, the corrected rand index, the value of objective function and iterations are introduced as the evaluation criterion. Clustering results demonstrate that the algorithm proposed in this paper has remarkable advantages.     

Dynamic Type-2 Fuzzy Dependent Dirichlet Regression Mixture clustering model

In this paper, a new dynamic Interval Type-2 Fuzzy Dependent Dirichlet Piecewise Regression Mixture (IT2FDDPRM) clustering model is proposed. The model overcomes shortcomings of both Dependent Dirichlet Process Mixture (DDPM) technique and Interval Type-2 Fuzzy C-regression Clustering Model (IT2FCRM). DDPM method demonstrates that the probability of assigning data to a cluster including the maximum number of data among all clusters is higher, and it ignores the similarity of data to a cluster. However, the new IT2FDDPRM clustering technique supports assignment of data to a cluster which has the most similarity to them. It also allows the model to generate infinite number of clusters. Moreover, it has the capability of segmenting functions assigned to clusters. The model is validated using statistical tests, three validity functions, and mean square error of the model. The results of numerical experiments show that the proposed method has superior performance to other clustering techniques in literature.     

A weighted multivariate Fuzzy C-Means method in interval-valued scientific production data

Clustering is the process of organizing objects into groups whose members are similar in some way. Most of the clustering methods involve numeric data only. However, this representation may not be adequate to model complex information which may be: histogram, distributions, intervals. To deal with these types of data, Symbolic Data Analysis (SDA) was developed. In multivariate data analysis, it is common some variables be more or less relevant than others and less relevant variables can mask the cluster structure. This work proposes a clustering method based on fuzzy approach that produces weighted multivariate memberships for interval-valued data. These memberships can change at each iteration of the algorithm and they are different from one variable to another and from one cluster to another. Furthermore, there is a different relevance weight associated to each variable that may also be different from one cluster to another. The advantage of this method is that it is robust to ambiguous cluster membership assignment since weights represent how important the different variables are to the clusters. Experiments are performed with synthetic data sets to compare the performance of the proposed method against other methods already established by the clustering literature. Also, an application with interval-valued scientific production data is presented in this work. Clustering quality results have shown that the proposed method offers higher accuracy when variables have different variabilities.     

区间序信息系统的无监督特征选择*

目前已有很多针对单值信息系统的无监督特征选择方法,但针对区间值信息系统的无监督特征选择方法却很少.针对区间序信息系统,文中提出模糊优势关系,并基于此关系扩展模糊排序信息熵和模糊排序互信息,用于评价特征的重要性.再结合一种综合考虑信息量和冗余度的无监督最大信息最小冗余(UmIMR)准则,构造无监督特征选择方法.最后通过实验证明文中方法的有效性.     

A new fuzzy clustering algorithm for the segmentation of brain tumor

This paper introduces a new method of clustering algorithm based on interval-valued intuitionistic fuzzy sets (IVIFSs) generated from intuitionistic fuzzy sets to analyze tumor in magnetic resonance (MR) images by reducing time complexity and errors. Based on fuzzy clustering, during the segmentation process one can consider numerous cases of uncertainty involving in membership function, distance measure, fuzzifier, and so on. Due to poor illumination of medical images, uncertainty emerges in their gray levels. This paper concentrates on uncertainty in the allotment of values to the membership function of the uncertain pixels. Proposed method initially pre-processes the brain MR images to remove noise, standardize intensity, and extract brain region. Subsequently IVIFSs are constructed to utilize in the clustering algorithm. Results are compared with the segmented images obtained using histogram thresholding, k-means, fuzzy c-means, intuitionistic fuzzy c-means, and interval type-2 fuzzy c-means algorithms and it has been proven that the proposed method is more effective.     

Interval type-2 fuzzy membership function generation methods for pattern recognition

Type-2 fuzzy sets (T2 FSs) have been shown to manage uncertainty more effectively than T1 fuzzy sets (T1 FSs) in several areas of engineering [4], [6], [7], [8], [9], [10], [11], [12], [15], [16], [17], [18], [21], [22], [23], [24], [25], [26], [27] and [30]. However, computing with T2 FSs can require undesirably large amount of computations since it involves numerous embedded T2 FSs. To reduce the complexity, interval type-2 fuzzy sets (IT2 FSs) can be used, since the secondary memberships are all equal to one [21]. In this paper, three novel interval type-2 fuzzy membership function (IT2 FMF) generation methods are proposed. The methods are based on heuristics, histograms, and interval type-2 fuzzy C-means. The performance of the methods is evaluated by applying them to back-propagation neural networks (BPNNs). Experimental results for several data sets are given to show the effectiveness of the proposed membership assignments.