基于空间分析的空间关联规则提取

空间关联规则是空间数据挖掘的一个重要结果表现形式，从GIS中挖掘空间关联规则是一个理解和将GIS中的数据转化成知识很好的方法。GIS从本质上讲是一个空间数据库管理系统，现在的商业空间数据库管理系统中都不能存储空间分析的关系如空间拓扑关系、空间相邻关系等。文章提出了一种基于空间分析的空间关联规则的挖掘算法，并给出了实例、分析及讨论。     

Meta-association rules for mining interesting associations in multiple datasets

Association rules have been widely used in many application areas to extract new and useful information expressed in a comprehensive way for decision makers from raw data. However, raw data may not always be available, it can be distributed in multiple datasets and therefore there resulting number of association rules to be inspected is overwhelming. In the light of these observations, we propose meta-association rules, a new framework for mining association rules over previously discovered rules in multiple databases. Meta-association rules are a new tool that convey new information from the patterns extracted from multiple datasets and give a “summarized” representation about most frequent patterns. We propose and compare two different algorithms based respectively on crisp rules and fuzzy rules, concluding that fuzzy meta-association rules are suitable to incorporate to the meta-mining procedure the obtained quality assessment provided by the rules in the first step of the process, although it consumes more time than the crisp approach. In addition, fuzzy meta-rules give a more manageable set of rules for its posterior analysis and they allow the use of fuzzy items to express additional knowledge about the original databases. The proposed framework is illustrated with real-life data about crime incidents in the city of Chicago. Issues such as the difference with traditional approaches are discussed using synthetic data.     

基于互信息的教育数据矩阵加权正负关联模式发现

本文将互信息模型引入教育数据关联模式挖掘,提出一种基于互信息的教育数据矩阵加权正负关联模式挖掘算法,给出与其相关的定理及其证明。本文算法克服了现有挖掘算法的缺陷,考虑了教育数据项集在学生信息数据库中具有的权值,采用新的正负关联模式评价标准,挖掘出更接近实际情况的正负关联模式。通过关联模式分析,发现教育数据中潜在有用的教育、教学规律和教育发展趋势,为教育管理、教育决策和教学改革提供科学的依据。以真实的教育数据作为实验数据测试集,实验结果表明,本文算法有效,在教育信息化数据处理与分析中具有重要的应用价值。     

一种基于最大加权频繁项目集的数据库相似性判别算法

在引入最大加权频繁项目集之后，给出一种新的数据库相似性度量模型，并提出基于最大加权频繁项目集的数据库相似性度量算法．该算法可有效地改进基于最大频繁项目集的数据库相似性度量方法，提高数据库相似性度量准确性．在实际应用中，改进模型为分布多库环境下数据挖掘的数据准备提供有效的框架，因而具有重要的使用价值．     

关联规则挖掘算法介绍

数据挖掘是一个多学科交叉融合而形成的新兴的学科,它利用各种分析工具在海量数据中发现模型和数据间的关系。而在大规模事务数据库中,挖掘关联规则是数据挖掘领域的一个非常重要的研究课题。文中介绍了关联规则挖掘的研究情况,描述了经典Apriori算法的实现,并对该算法进行了分析和评价,指出了其不足和原因。描述了FP树挖掘最大频繁项集的算法,通过实例对该算法进行了性能评估,并得到结论:数据库中潜在的最大频繁模式越多,运行时间越长。     

An effective mining approach for up-to-date patterns

Mining association rules is most commonly seen among the techniques for knowledge discovery from databases (KDD). It is used to discover relationships among items or itemsets. Furthermore, temporal data mining is concerned with the analysis of temporal data and the discovery of temporal patterns and regularities. In this paper, a new concept of up-to-date patterns is proposed, which is a hybrid of the association rules and temporal mining. An itemset may not be frequent (large) for an entire database but may be large up-to-date since the items seldom occurring early may often occur lately. An up-to-date pattern is thus composed of an itemset and its up-to-date lifetime, in which the user-defined minimum-support threshold must be satisfied. The proposed approach can mine more useful large itemsets than the conventional ones which discover large itemsets valid only for the entire database. Experimental results show that the proposed algorithm is more effective than the traditional ones in discovering such up-to-date temporal patterns especially when the minimum-support threshold is high.     

Analysis of QoS in cooperative services for real time applications

Discovering frequent patterns in large databases is one of the most studied problems in data mining, since it can yield substantial commercial benefits. However, some sensitive patterns with security considerations may compromise privacy. In this paper, we aim to determine appropriate balance between need for privacy and information discovery in frequent patterns. A novel method to modify databases for hiding sensitive patterns is proposed in this paper. Multiplying the original database by a sanitization matrix yields a sanitized database with private content. In addition, two probabilities are introduced to oppose against the recovery of sensitive patterns and to reduce the degree of hiding non-sensitive patterns in the sanitized database. The complexity analysis and the security discussion of the proposed sanitization process are provided. The results from a series of experiments performed to show the efficiency and effectiveness of this approach are described.     

基于DDMINER分布式数据库系统中频繁项目集的更新

给出了一种分布式数据挖掘系统的体系结构DDMINER，对分布式数据库系统中频繁项目集的更新问题进行探讨，既考虑了数据库中事务增加的情况，又考虑了事务删除的情况；提出了一种基于DDMINER的局部频繁项目集的更新算法ULF和全局频繁项目集的更新算法UGF．该算法能够产生较少数量的候选频繁项目集，在求解全局频繁项目集过程中，传送候选局部频繁项目集支持数的通信量为O(n)；将文章提出的算法用Java语言加以实现，并对算法性能进行了研究；实验结果表明这些算法是正确、可行的，并且具有较高的效率．     

一种适应大型数据库的多支持度关联规则算法

关联规则挖掘一直是数据挖掘中的重要组成部分。提出一个新算法DPCFP-growth算法。DPCFP-growth算法是基于MSApirori算法,采用了CFP-growth分而治之的思想,并弥补了CFP-growth算法的不足。CFP-growth算法运行时要把整个数据库中的数据压缩到一个MIS-tree中然后进行频繁模式挖掘。在大型数据库中CFP-growth算法会建立一个深度很深宽度很宽的CFP-tree,以至于内存往往不能满足其要求,被迫使用大量的辅存,致使算法的运行效率急剧下降。DPCFP-growth算法根据CFP-tree的特征,有效地把大数据库分为若干个内存可以满足其要求的子数据库,然后在每个子数据库中进行局部频繁模式挖掘,最终汇总这些频繁模式生成全局频繁模式。实验表明该算法是正确的,并且在大型数据挖掘中,比CFP-growth算法有一定的优越性。     

一种高效的关联规则增量式更新算法

针对在最小支持度、最小置信度不变的情况下,新增数据集时关联规则更新问题,提出了一种新的关联规则的更新算法.该算法采用AprioriTidList算法来发现新增数据集中的频繁项集,并对候选项集进行分类和剪裁,从而减少了扫描原数据库和新增数据库的次数,提高了更新效率.实验结果表明新算法是有效可行的.     

关联规则在空间数据挖掘中的应用及实现

空间数据挖掘是从空间数据库中抽取隐含知识、空间关系及空间数据库中存储的其它信息的方法。空间关联规则是空间数据挖掘的一个重要研究领域,利用空间关联规则把空间数据库中的数据转化为知识是一个很好的方法。在分析空间关联规则的基础上,用基于关联规则的逐步求精挖掘算法,得出空间数据库中的隐含知识,通过实例证明其方法的可行性。     

Privacy preserving association rule mining over distributed databases using genetic algorithm

Privacy preservation in distributed database is an active area of research. With the advancement of technology, massive amounts of data are continuously being collected and stored in distributed database applications. Indeed, temporal associations and correlations among items in large transactional datasets of distributed database can help in many business decision-making processes. One among them is mining frequent itemset and computing their association rules, which is a nontrivial issue. In a typical situation, multiple parties may wish to collaborate for extracting interesting global information such as frequent association, without revealing their respective data to each other. This may be particularly useful in applications such as retail market basket analysis, medical research, academic, etc. In the proposed work, we aim to find frequent items and to develop a global association rules model based on the genetic algorithm (GA). The GA is used due to its inherent features like robustness with respect to local maxima/minima and domain-independent nature for large space search technique to find exact or approximate solutions for optimization and search problems. For privacy preservation of the data, the concept of trusted third party with two offsets has been used. The data are first anonymized at local party end, and then, the aggregation and global association is done by the trusted third party. The proposed algorithms address various types of partitions such as horizontal, vertical, and arbitrary.

     

挖掘数据库中的负频繁模式

传统的关联规则挖掘研究事务中所包含的项与项之间的关联性,而负关联规则挖掘不仅要考虑事务中包含的项,还要考虑事务中不包含的项。给出了完全负关联规则的定义,提出一种基于树的算法Free-PNP,通过此算法挖掘数据库中的负频繁模式,继而得到所要挖掘的完全负关联规则。通过实验验证了算法的有效性。     

概念漂移数据流挖掘算法综述

数据流是一种新型的数据模型,具有动态、无限、高维、有序、高速和变化等特性。在真实的数据流环境中,一些数据分布是随着时间改变的,即具有概念漂移特征,称为可变数据流或概念漂移数据流。因此处理数据流模型的方法需要处理时空约束和自适应调整概念变化。对概念漂移问题和概念漂移数据流分类、聚类和模式挖掘等内容进行综述。首先介绍概念漂移的类型和常用概念改变检测方法。为了解决概念漂移问题,数据流挖掘中常使用滑动窗口模型对新近事务进行处理。数据流分类常用的模型包括单分类模型和集成分类模型,常用的方法包括决策树、分类关联规则等。数据流聚类方式通常包括基于k- means的和非基于k- means的。模式挖掘可以为分类、聚类和关联规则等提供有用信息。概念漂移数据流中的模式包括频繁模式、序列模式、episode、模式树、模式图和高效用模式等。最后详细介绍其中的频繁模式挖掘算法和高效用模式挖掘算法。     

Discovering Transitional Patterns and Their Significant Milestones in Transaction Databases

A transaction database usually consists of a set of time-stamped transactions. Mining frequent patterns in transaction databases has been studied extensively in data mining research. However, most of the existing frequent pattern mining algorithms (such as Apriori and FP-growth) do not consider the time stamps associated with the transactions. In this paper, we extend the existing frequent pattern mining framework to take into account the time stamp of each transaction and discover patterns whose frequency dramatically changes over time. We define a new type of patterns, called transitional patterns, to capture the dynamic behavior of frequent patterns in a transaction database. Transitional patterns include both positive and negative transitional patterns. Their frequencies increase/decrease dramatically at some time points of a transaction database. We introduce the concept of significant milestones for a transitional pattern, which are time points at which the frequency of the pattern changes most significantly. Moreover, we develop an algorithm to mine from a transaction database the set of transitional patterns along with their significant milestones. Our experimental studies on real-world databases illustrate that mining positive and negative transitional patterns is highly promising as a practical and useful approach for discovering novel and interesting knowledge from large databases.     

数据库中加权关联规则的发现

关联规则发现是数据库中知识发现研究中的热点课题,有着广泛的应用领域.在现有的研究中,数据库中的各个项目是按平等一致的方式加以处理的.然而,在现实世界数据库中却并非如此,不同的项目往往有着不同的重要性.为了将它们反映出来,对项目引入权值,从而提出了新的加权关联规则问题.由于项目权值的引入,频繁项目集的子集不再一定是频繁的.为此,又提出了项目的k-支持期望概念,并由此提出了加权关联规则的发现算法.     

Incrementally building frequent closed itemset lattice

A concept lattice is an ordered structure between concepts. It is particularly effective in mining association rules. However, a concept lattice is not efficient for large databases because the lattice size increases with the number of transactions. Finding an efficient strategy for dynamically updating the lattice is an important issue for real-world applications, where new transactions are constantly inserted into databases. To build an efficient storage structure for mining association rules, this study proposes a method for building the initial frequent closed itemset lattice from the original database. The lattice is updated when new transactions are inserted. The number of database rescans over the entire database is reduced in the maintenance process. The proposed algorithm is compared with building a lattice in batch mode to demonstrate the effectiveness of the proposed algorithm.     

快速多层次关联规则的挖掘

知识发现是指对原始数据进行分析，提取出隐含的，有用的规则，是当前快速发展的研究领域，是知识获取的重要方法，关联规则是知识发现的重要研究内容之一，本文提出了一种新的多层次关联规则挖掘算法ＭＬ＿ＡＲ，算法ＭＬ＿ＡＲ在挖掘过程中，只对最低概括层次上的候选系模式进行模式的匹配计算，求解出简化的频繁式集合，最后再求解各个概括层次上的繁频模式集合，算法ＭＬ＿ＡＲ有效地利用了概括的层次关系，减少了模式的匹配计算     

一种新的基于FP-Tree的关联规则增量式更新算法

挖掘关联规则是数据挖掘研究的一个重要方面,目前已经提出了许多算法用于高效地发现大规模数据库中的关联规则,而维护已发现的关联规则同样是重要的.针对在事务数据库增加和最小支持度同时发生变化的情况下,如何进行关联规则的更新问题进行了研究,提出了一种新的基于频繁模式树的关联规则增量式更新算法,并对该算法进行了分析和讨论.     

基于关联规则的空间数据知识发现及实现

空间数据挖掘就是从空间数据库中抽取隐含知识、空间关系及空间数据库中存储的其它模式的方法。空间关联规则是空间数据挖掘的一个重要表现形式,利用空间关联规则把空间数据库中的数据转化为知识是一个很好的方法。本文在分析空间关联规则的基础上,用基于关联规则的逐步求精挖掘算法,得出空间数据库中的知识,通过实例证明其方法的可行性。