共查询到20条相似文献,搜索用时 78 毫秒
1.
一种稳健的聚类方法 总被引:5,自引:0,他引:5
张媛祥 《数学的实践与认识》2003,33(8):8-10
本文讨论一种新的聚类方法 :属性均值聚类 .通过理论分析 ,属性均值聚类是比模糊均值聚类更稳健的聚类方法 .数值实验说明了该方法的有效性 相似文献
2.
3.
4.
5.
传统的聚类方法由于无法提取样本和变量间的局部对应关系,并且当数据具有高维性和稀疏性时表现不佳,因此学者们提出了双向聚类,基于样本和变量间的局部关系,同时对样本和变量进行聚类,形成一系列子矩阵的聚类结果。近年来,双向聚类发展迅速,在基因分析、文本聚类、推荐系统等领域应用广泛。首先,对双向聚类方法进行梳理与归纳,重点阐述稀疏双向聚类、谱双向聚类和信息双向聚类三类方法,分析它们之间的区别和联系,并且介绍这三类方法在多源数据的整合分析、多层聚类、半监督学习以及集成学习上的发展现状和趋势;其次,重点介绍双向聚类在基因分析、文本聚类、推荐系统等领域的应用研究情况;最后,结合大数据时代的数据特征和双向聚类存在的问题,展望双向聚类未来的研究方向。 相似文献
6.
在不同的实际问题中,往往视需要使用不同的准则对模式进行聚类。本文给出了一个聚类准则,并使用该准则用人工神经网络方法在计算机上进行了模拟。结果表明本文使用的聚类准则更适合于用人工神经网络实现,可以取得极好的聚类效果。 相似文献
7.
系统聚类递推公式推广 总被引:1,自引:0,他引:1
本文推广了系统聚类法的最短距离法、最长距离法,平均距离法,中国距离法,重心法,类平均法、离差平方和法、可变法、可变类平均法的递推公式,并给出了统一计算公式。 相似文献
8.
硬聚类和模糊聚类的结合——双层FCM快速算法 总被引:3,自引:0,他引:3
模糊c均值(FCM)聚类算法在模式识别领域中得到了广泛的应用,但FCM算法在大数据集的情况下需要大量的CPU时间,令用户感到十分不便,提高算法的速度是一个急待解决的问题。本文提出的双层FCM聚类算法是一种快速算法,它体现了硬聚类和模糊聚类的结合,以硬聚类的结果对模糊聚类的初始值进行指导,从而明显地缩短了迭代过程。双层FCM算法所用的CPU时间仅为FCM算法的十三分之一,因而具有很强的实用价值。 相似文献
9.
10.
目前模糊技术已经应用于许多智能系统,如模糊关系与模糊聚类.聚类是数据挖掘的重要任务,它将数据对像分成多个聚类,在同一个聚类中,对象的属性特征之间具有较高的相似度,有很大研究及应用价值.结合数据库中的挖掘技术,对属性特征为区间数的多属性决策问题,提出了一种基于区间数隶属度的区间模糊ISODATA动态聚类方法. 相似文献
11.
We construct quantized versions of generic bases in quantum cluster algebras of finite and affine types.Under the specialization of q and coefficients to 1,these bases are generic bases of finite and affine cluster algebras. 相似文献
12.
区域价值链集群分析是集群分析作为区域经济创新性和竞争优势分析工具的重要表现形式。而区域价值链集群识别是进行区域价值链集群分析的第一步。为了实现区域价值链集群依据经济系统各部门间网络互动联系来确定其核心主导产业及其前后向密切关联产业的识别目标,本文选取了以最大值法和投入产出分析法相结合的区域价值链识别方法。由此进行的识别研究表明,上海共有通信、化工、通专、金属、石油核燃料五类价值链集群,它们通过内部和彼此间的互动交织构成了密切关联的网络,并在很大程度上反映了上海经济系统的核心组成。而相应的经济技术分析表明,通专价值链集群将很有可能在上海大力发展先进制造业的产业结构升级大背景下赶超通信价值链集群而成为新一轮发展的亮点。 相似文献
13.
We study the relations between two groups related to cluster automorphism groups which are defined by Assem,Schiffler and Shamchenko.We establish the relation-ships among (strict) direct cluster automorphism groups and those groups consisting of periodicities of labeled seeds and exchange matrices,respectively,in the language of short exact sequences.As an application,we characterize automorphism-finite cluster algebras in the cases of bipartite seeds or finite mutation type.Finally,we study the relation between the group Aut(A) for a cluster algebra A and the group AutMn(S) for a mutation group Mn and a labeled mutation class S,and we give a negative answer via counter-examples to King and Pressland's problem. 相似文献
14.
Let H be a finite-dimensional hereditary algebra over an algebraically closed field k and C F m be the repetitive cluster category of H with m ≥ 1. We investigate the properties of cluster tilting objects in C F m and the structure of repetitive clustertilted algebras. Moreover, we generalize Theorem 4.2 in [12] (Buan A, Marsh R, Reiten I. Cluster-tilted algebra, Trans. Amer. Math. Soc., 359(1)(2007), 323-332.) to the situation of C F m , and prove that the tilting graph KCFm of C F m is connected. 相似文献
15.
Christian Richter 《Set-Valued Analysis》2006,14(1):25-40
Given a single-valued function f between topological spaces X and Y, we interpret the cluster set C(f;x) as a multivalued function F=C(f;⋅) associated to f – the cluster function of f. For appropriate metrizable spaces X and Y, we characterize cluster functions C(f;⋅) among arbitrary set-valued functions F and show that every cluster function F=C(f;⋅) admits a selection h of Baire class 2 such that F=C(h;⋅).
Mathematics Subject Classifications (2000) Primary: 54C50, 54C60; secondary: 26A21, 54C65.This research was partially supported by DFG Grant RI 1087/2. 相似文献
16.
17.
Let H be a finite-dimensional hereditary algebra over an algebraically closed field k and CFm be the repetitive cluster category of H with m ≥ 1. We investigate the properties of cluster tilting objects in CFm and the structure of repetitive cluster-tilted algebras. Moreover, we generalize Theorem 4.2 in [12] (Buan A, Marsh R, Reiten I. Cluster-tilted algebra, Trans. Amer. Math. Soc., 359(1)(2007), 323-332.) to the situation of CFm, and prove that the tilting graph KCFm of CFm is connected. 相似文献
19.
ZHU Bin Department of Mathematical Sciences Tsinghua University Beijing China 《中国科学A辑(英文版)》2006,49(12):1839-1854
Given a symmetrizable generalized Cartan matrix A, for any index k, one can define an automorphism associated with A, of the field Q(u1,…, un) of rational functions of n independent indeterminates u1,…,un.It is an isomorphism between two cluster algebras associated to the matrix A (see sec. 4 for the precise meaning). When A is of finite type, these isomorphisms behave nicely; they are compatible with the BGP-reflection functors of cluster categories defined in a previous work if we identify the indecomposable objects in the categories with cluster variables of the corresponding cluster algebras, and they are also compatible with the "truncated simple reflections" defined by Fomin-Zelevinsky. Using the construction of preprojective or preinjective modules of hereditary algebras by DIab-Ringel and the Coxeter automorphisms (i.e. a product of these isomorphisms), we construct infinitely many cluster variables for cluster algebras of infinite type and all cluster variables for finite types. 相似文献
20.
It is proved that any cluster-tilted algebra defined in the cluster category 𝒞(H) has the same representation type as the initial hereditary algebra H. For any valued quiver (Γ, Ω), an injection from the subset 𝒫?(Ω) of the cluster category 𝒞(Ω) consisting of indecomposable preprojective objects, preinjective objects, and the first shifts of indecomposable projective modules to the set of cluster variables of the corresponding cluster algebra 𝒜Ω is given. The images are called “preprojective cluster variables”. It is proved that all preprojective cluster variables other than ui have denominators u dim M in their irreducible fractions of integral polynomials, where M is the corresponding preprojective module or preinjective module. In case the valued quiver (Γ, Ω) is of finite type, the denominator theorem holds with respect to any cluster. Namely, let x = (x1,…, xn) be a cluster of the cluster algebra 𝒜Ω, and V the cluster tilting object in 𝒞(Ω) corresponding to x, whose endomorphism algebra is denoted by Λ. Then the denominator of any cluster variable y other than xi is x dim M, where M is the indecomposable Λ-module corresponding to y. This result is a generalization of the corresponding result of Caldero–Chapoton–Schiffler to the non-simply-laced case. 相似文献