共查询到20条相似文献，搜索用时 171 毫秒
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周文刚 《周口师范高等专科学校学报》2002,19(2):75-78
EPs可以用来在数据库中进行知识发出，也可以捕获时标数据库中的显露趋势或数据类之间的有用对比。由于Apriori属性对EPs不再适用，而且多维数据或小支持度阈值（如0．5％）有太多的侯选项集。对此Naive算法代价太大，这使得EPs的有效挖掘成为一个挑战性问题。为解决这些问题，本文介绍使用精确的描述大型项集集合， 设计只操作边界集的EPs挖掘算法，并且使用边界表示已发现的EPs。 相似文献
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关联规则挖掘可以发现大量数据中项集之间有趣的关联或相关联系,并已在许多领域得到了广泛的应用.Apriori算法是挖掘关联规则最基本,最核心的算法之一.但Apriori算法只考虑交易中项出现的频率,没有考虑事务集不同项及记录具有不同的重要性,挖掘出来的规则具有一定的局限性.针对这点不足本文提出一种记录加权关联规则挖掘,结合Apriori算法并加以改进,给出相应的New-Aproiri算法. 相似文献
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杨种学 《南京晓庄学院学报》2005,21(5):65-70
发现关联规则是数据挖掘技术的重要任务之一。之前提出的绝大多数算法需要多次遍历数据库才能产生频繁项集,造成巨大的CPU和内存开销。根据网上交易数据海量的特点,提出了一种基于频繁模式增长(FP-growth)的并行算法。该算法可以在不产生候选集的基础上并行的挖掘海量数据。试验证明该算法可以缓解了项目数量巨大而内存不足的矛盾,减少了算法的执行时间。利用该算法对网上交易进行关联规则挖掘,发现了有价值的决策支持信息。 相似文献
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黄艺坤 《周口师范学院学报》2015,(2):129-131
通过对数据挖掘技术的研究,笔者使用关联规则中的Apriori算法对无纸化考试系统的数据库进行了分析和挖掘,实现了对Apriori算法的改进和运算.本文的方法通过构建相关高频集,可以对不同分数等级的学生数据进行加权处理,使得高频集中的数据在数据仓库中更加明显,从而令无纸化考试系统更科学地组装试卷. 相似文献
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关联规则是数据挖掘中一个非常重要的任务,有许多针对于关联规则的挖掘算法,然而需要提高算法的有效性来处理现实世界中的数据集。基于聚类的关联规则挖掘算法法通过扫描数据库创建聚类表,将收集的事务记录放入聚类表中,通过局部聚类表的约束来产生频繁项集,不仅可以剪枝候选项集,降低数据扫描的时间,而且确保挖掘结果集的正确性。实验结果表明,基于聚类的关联规则挖掘算法比Apfiori算法有更高的执行效率。 相似文献
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冯凤 《合肥联合大学学报》2007,17(4):46-49
更新挖掘最大频繁项目集是多种数据挖掘应用中的重要问题，其发现过程的高花费要求对高效更新挖掘算法进行研究，提出了一种快速的更新挖掘最大频繁项目集算法，其能够在原有挖掘结果的基础上，有效地挖掘出更新后的数据库中隐含的新最大频繁项目集． 相似文献
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为了解决频繁闭项目集挖掘中时间和存储开销大的问题,提出了一种基于FC-tree（频繁闭模式树）的频繁闭项目集挖掘算法max-FCIA（最大频繁闭项目集挖掘算法）.该算法利用哈希表映射事务数据库,通过对哈希表进行操作从而得到所有频繁项目集的支持度,进而生成包含所有频繁项目的有序树.经过剪枝处理的有序树就是包含所有最小频繁闭项目集的FC-tree,最后用最小频繁闭项目集生成频繁闭项目集.实验结果表明,该算法通过映射事务数据库,减少了扫描数据库所浪费的时间,提高程序执行效率.另外,运用有效的剪枝策略,避免了不必要候选项目集的生成,节省了存储空间,实验证明该算法是有效的. 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献