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频繁项集快速挖掘及更新算法 总被引:2,自引:0,他引:2
为了克服Apriori发现频繁项集存在的问题,提出了一种基于三维项集矩阵和向量(TIMV)的频繁项集挖掘算法.该算法摆脱了Apriori框架的束缚,仅需扫描数据库一次,不产生候选项目集.当事务数据库和最小支持度发生变化时,该算法只需重新遍历一次项集矩阵,即可得到新的频繁项集.实验结果表明,算法能有效提高频繁项目集的挖掘和更新效率. 相似文献
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挖掘最大频繁项目集是数据挖掘中的重要研究课题。目前已经提出的最大频繁项目集挖掘算法大多是基于单机环境的,在分布环境中挖掘最大频繁项目集的算法尚不多见。文章提出了一种基于分布数据库的并行挖掘最大频繁项目集的算法。该算法尽可能地让每个处理器独立地挖掘,采用频繁模式树(FP—tree)作为数据结构,可方便地从各局部FP-tree中挖掘局部最大频繁项目集及判断各项目集的支持度。采用传递候选最大频繁项目集的方法。实验表明该算法是有效的并行算法。 相似文献
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提出了一种有效的增量式关联规则挖掘算法IAR,算法的特点在于:提出并采用了基于候选项集个数上阶的选择扫描数据库的机制,可有效减少数据库的扫描次数;算法是一种通用的增量式算法,提出了最小支持度和数据库均改变时,增量式挖掘中的重要性质,从而可充分利用上一次挖掘的结果,有效减少候选项集的数目.并且提出了基于组合数学和项集等价类理论的计算候选项集个数的上阶的方法.通过大量的数据实验,表明算法的效率比已有的算法有了很大提高. 相似文献
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提出了一种基于频繁模式矩阵(FP-array)的约束最大频繁项目集挖掘及其更新算法。算法只扫描事务数据库一遍,把满足约束条件的所有事务转换成一个频繁模式矩阵,显著缩小了FP-array的大小规模。挖掘过程采用逻辑运算,在效率上有独特的优势。实验结果表明该算法是快速有效的。 相似文献
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加权最大频繁项目集挖掘算法 总被引:2,自引:0,他引:2
关联规则是数据挖掘领域的一个重要分支,而发现最大频繁项目集是关联规则挖掘中的重要问题.最大频繁项目集挖掘是在数据库中各属性之间是平等的情况下进行的,但现实中并非如此.频繁模式树(Frequent Pattern Tree,FP-Tree)已不能满足要求.为此提出了一个有效的基于加权FP-Tree的加权最大频繁项目集挖掘算法,其挖掘过程中不需要产生候选项目集.并通过实例说明了此算法的挖掘过程.实验结果表明此算法是有效的并且有较好的扩展性. 相似文献
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随着互联网的快速发展,Web数据挖掘已经成为当今热门的研究主题。本文介绍了Web数据挖掘的基本概念、Web数据的特点及其Web数据挖掘分类,并对Web数据挖掘技术的研究进行讨论。利用Apriori算法发现频繁集,找到页面间的关联规则。针对网页超链接结构的特点:一条超链接只能建立在两个网页上,发现频繁集只要找出所有2-项集即可,从而提出网页超链接挖掘的NApriori算法。NApriori算法显著提高了Apriori算法的效率。 相似文献
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Neural network pruning techniques can be effective in accelerating neural network models, making it possible to deploy them on edge devices. In this paper, we propose to prune neural networks using data variance. Unlike other existing methods, this method is somewhat robust and does not invalidate our criteria depending on the number of data batches and the number of training sessions. We also propose a pruning compensation technique. This technique fuses the pruned convolutional information into the remaining convolutional kernel close to it. This fusion operation can effectively help retain the pruned information. We evaluate the proposed method on a number of standard datasets and compare it with several current state-of-the-art methods. Our method always achieves better performance. For example, on Tiny ImageNet, our method can prune 54.2% FLOPs of ResNet50 while obtaining a 0.22% accuracy improvement. 相似文献
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Decorrelation: A Theory for Block Cipher Security 总被引:2,自引:0,他引:2
Pseudorandomness is a classical model for the security of block ciphers.
In this paper we propose convenient tools in order to study it in connection
with the Shannon Theory, the Carter–Wegman universal hash functions paradigm,
and the Luby–Rackoff approach.
This enables the construction of new ciphers with security proofs under
specific models.
We show how to ensure security against basic differential and linear
cryptanalysis and even more general attacks.
We propose practical construction schemes. 相似文献
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Current designs of high-speed networks assume that all customers are tolerant of some amount of losses. However, it is possible that some applications may require very high reliability, and would be willing to pay more for it, if such a service were available. Motivated by this, we propose a design of a hybrid network which can guarantee zero cell loss probability for type 1 traffic while allowing some losses for type 2 traffic. This paper has three contributions. Our first contribution in this paper is to propose a service discipline (which can be implemented easily on a specific switch architecture) which guarantees zero losses for type 1 traffic. Our second contribution is to propose an algorithm for a scheduling strategy which reduces the number of buffers required at the output pods of the switches to zero for type 1 traffic. Our last contribution is to solve a difficult queueing problem involving service interruptions, which characterizes the performance of type 2 traffic 相似文献
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瓶口、瓶盖模具螺纹的加工没有进刀、退刀位置,因此加工困难。本文通过分析该类螺纹加工的主要难点,提出解决这类螺纹加工的有效方案,实现一定的经济效益。 相似文献
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In this paper, we propose a novel crypto-watermarking system for the purpose of verifying the reliability of medical images and tracing them, i.e. identifying the person at the origin of an illegal disclosure. This system couples a common watermarking method, based on Quantization Index Modulation (QIM), and a joint watermarking-decryption (JWD) approach. At the emitter side, it allows the insertion of a watermark as a proof of reliability of the image before sending it encrypted; at the reception, another watermark, a traceability proof, is embedded during the decryption process. The scheme we propose makes interoperate these two watermarking approaches taking into account risks of interferences between embedded watermarks, allowing the access to both reliability and traceability proofs. Experimental results confirm the efficiency of our system, and demonstrate it can be used to identify the origin of a disclosure even if the image has been altered. 相似文献
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本文对中国移动骚扰电话治理工作以及当前的治理形势进行梳理,总结归纳了骚扰电话治理面对的风险与挑战,分析并提出了骚扰电话治理的发展方向,为下一步骚扰电话治理工作提供了思路。 相似文献
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本文提出了基于编辑距离的XML查询方法,它主要是打破传统的结构查询在前,内容查询在后的做法,目的是提高XML查询的查准率.它主要分为内容查询和结构查询两步进行,在内容查询的时候,首次提出分类因子,并且由此得出了关键词加权公式;在结构查询的时候,用删除操作,插入操作,替换操作完成了编辑距离的匹配;最后按照权重值大小进行排... 相似文献