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XML(eXtensible Markup Language)is a standard which is widely applied in data representation and data exchange,However,as an important concept of XML,DTD(Document Type Definition)is not taken full advantage in current applications.In this paper,a new method for clustering DTDs is presented.and it can be used in XML document clustering.The two-level method clusters the elements in DTDs and clusters DTDs separately.Element clustering forms the first level and provides element clusters,which are the generalization of relevant elements.DTD clustering utilizes the generalized information and forms the second level in the whole clustering process.The two-level method has the following advantages:1) It takes into consideration both the content and the structure within DTDs;2) The generalized information about elements is more useful than the separated words in the vector model;3) The two-level method facilitates the searching of outliers.The experiments show that this method is able to categorize the relevant DTDs effectively. 相似文献
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梁宇奇 《中国石油和化工标准与质量》2012,32(6):183
高邮沙埝地区是高邮凹陷的主力勘探区之一,也是一个辉绿岩发育,开发前景广阔的地区.在地质资料基础上,研究辉绿岩的空间展布,根据辉绿岩的分布特征和发育情况,分析高邮凹陷沙25断块辉绿岩侵入对油气层影响,为今后地质录井工作提供可靠依据。 相似文献
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基于SQL的XML查询的有效实现 总被引:7,自引:1,他引:7
讨论了关系数据库中利用SQL语句实现XML查询的问题,首先提出了一个利用映射信息(映射图)将带正则路径表达式的XML查询重写为一组简单路径查询的算法,该过程中的一个关键问题的Kleene表达式不能直接利用映射图重写,为此,提出了利用路径实例的统计信息来扩展Kleene表达式的算法,然后,进一步描述了将简单路径表达式查询重写为SQL查询的方法,这些算法在XML-关系系统原型VXMLR中实现,初步性能研究表明提出了方法是有效的。 相似文献
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