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31.
Non-redundant data clustering 总被引:6,自引:6,他引:0
Data clustering is a popular approach for automatically finding classes, concepts, or groups of patterns. In practice, this
discovery process should avoid redundancies with existing knowledge about class structures or groupings, and reveal novel,
previously unknown aspects of the data. In order to deal with this problem, we present an extension of the information bottleneck
framework, called coordinated conditional information bottleneck, which takes negative relevance information into account by maximizing a conditional mutual information score subject to
constraints. Algorithmically, one can apply an alternating optimization scheme that can be used in conjunction with different
types of numeric and non-numeric attributes. We discuss extensions of the technique to the tasks of semi-supervised classification
and enumeration of successive non-redundant clusterings. We present experimental results for applications in text mining and
computer vision. 相似文献
32.
This paper introduces and evaluates a new class of knowledge model, the recursive Bayesian multinet (RBMN), which encodes the joint probability distribution of a given database. RBMNs extend Bayesian networks (BNs) as well as partitional clustering systems. Briefly, a RBMN is a decision tree with component BNs at the leaves. A RBMN is learnt using a greedy, heuristic approach akin to that used by many supervised decision tree learners, but where BNs are learnt at leaves using constructive induction. A key idea is to treat expected data as real data. This allows us to complete the database and to take advantage of a closed form for the marginal likelihood of the expected complete data that factorizes into separate marginal likelihoods for each family (a node and its parents). Our approach is evaluated on synthetic and real-world databases. 相似文献
33.
34.
It seems clear that, for whatever reasons, the dementia of the Alzheimer type patient group (as well as other patient groups) exhibits behavior that is different from the normal control group. G. Storms, T. Dirikx, J. Saerens, S. Verstraeten, and P. P. De Deyn (2003) rightfully argue that the observed behavior (similarity judgments) does not tell us the source (cause) of the differences between the 2 groups. Rather, the focus of the study should be placed more on finding the ways the 2 groups are different. They also point out various methodological problems in some of the previous attempts to characterize the nature of the differences. Further methodological issues in G. Storms et al.'s study are examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
36.
Randall Billi; Moss Helen E.; Rodd Jennifer M.; Greer Mike; Tyler Lorraine K. 《Canadian Metallurgical Quarterly》2004,30(2):393
Patients with category-specific deficits have motivated a range of hypotheses about the structure of the conceptual system. One class of models claims that apparent category dissociations emerge from the internal structure of concepts rather than fractionation of the system into separate substores. This account claims that distinctive properties of concepts in the living domain are vulnerable because of their weak correlation with other features. Given the assumption that mutual activation among correlated properties produces faster activation in the normal system, the authors predicted a disadvantage for the distinctive features of living things for unimpaired adults. Results of a speeded feature verification study supported this prediction, as did a computational simulation in which networks mapped from orthography to semantics. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
37.
本文介绍了一个用Turbo C语言在AST-286机器上实现的计算机辅助数据库设计系统CAD^2B。该系统提供了人机交互的环境,供设计者进行概念模型设计,并自动完成从概念模型逻辑模型的映射,创建满足规范化要求的关系表。该系统采用的概念模型是引入了事件和时间的扩展了的实体关系模型。该模型既能充分反映应用环境的静态和动态语义,又是向关系模式转化的基础。 相似文献
38.
Ibrahim H. Osman Nicos Christofides 《International Transactions in Operational Research》1994,1(3):317-336
The capacitated clustering problem (CCP) is the problem in which a given set of weighted objects is to be partitioned into clusters so that the total weight of objects in each cluster is less than a given value (cluster ‘capacity’). The objective is to minimize the total scatter of objects from the ‘centre’ of the cluster to which they have been allocated. A simple constructive heuristic, a R-interchange generation mechanism, a hybrid simulated annealing (SA) and tabu search (TS) algorithm which has computationally desirable features using a new non-monotonic cooling schedule, are developed. A classification of the existing SA cooling schedules is presented. The effects on the final solution quality of the initial solutions, the cooling schedule parameters and the neighbourhood search strategies are investigated. Computational results on randomly generated problems with size ranging from 50 to 100 customers indicate that the hybrid SA/TS algorithm out-performs previous simulated annealing algorithms, a simple tabu search and local descent algorithms. 相似文献
39.
模糊聚类在三维地震参数处理中的应用 总被引:1,自引:1,他引:0
三维地震参数是一个庞大的三维数据体,能从不同侧面反映储集层的特征。通过对三维地震参数的分析,可以评估油藏表征的参数(沉积相、构造、生长历史、流体饱和度等)。针对传统的聚类方法不能很好地综合考虑各个参数之间的相似程度,提出了用模糊C-均值聚类(fuzzy c-means clustering,简称FCM)对三维地震参数进行处理。从三维地震参数和油藏表征参数之间的关系出发,采用模糊C-均值聚类方法对三维地震参数进行处理,依此评估油藏表征的参数。测试结果表明,模糊C-均值聚类方法能够对三维地震参数进行较为准确的分类,并为储集层的研究提供了很好的依据。 相似文献
40.