共查询到16条相似文献，搜索用时 93 毫秒
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基于域加权词频法的XML文档级检索实现与评价 总被引：1，自引：0，他引：1
利用BM25F模型,通过实验,在INEX 04数据集的基础上,实现了对多个域(元素)词频进行加权的XML文档级检索。XML文档结构的确蕴含了一定的语义信息。利用这些语义信息,可以提高检索性能。表2。图1。参考文献16。 相似文献
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对数字图书馆统一检索平台的核心问题进行了介绍,在对XML和WebService介绍基础之上提出了基于XML与WebService相结合的数字图书馆同意检索的总体模型,并对如何利用该模型建立统一检索平台进行实证研究。 相似文献
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基于文档权重归并法的企业专家检索* 总被引：2，自引：0，他引：2
针对企业专家的专长识别与检索问题,采用文档权重归并法,利用TREC W3C数据集实现企业内的专家检索,并与专家档案法进行了比较。研究结果表明同样采用BM25模型,采用文档权重归并法具有稳定的优势。 相似文献
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刘丹 《现代图书情报技术》2010,26(5):50-57
研究将XML文本检索方法应用于长文本环境,并以中文博硕士论文为数据集。对博硕士论文数据集的XML标引、索引、关键词检索和结构化检索分别进行设计和实现,构建一个基于XML的中文博硕士论文检索系统。 相似文献
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基于OKAPI的XML信息检索实现研究 总被引：3，自引：1，他引：3
OKAPI能实现强大的自由文本检索与评价功能,但要实现基于XML的信息检索,却要做适当改造。改造时,一方面尽量不破坏原有系统的体系结构,又要能实现对XML文档的索引、查询和表示。为此,必须完成面向XML的文档预处理和索引、面向XML的文档检索及检索模型的选择。图3。公式3。参考文献10。 相似文献
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针对信息检索角度的XML的结构化检索问题,利用基于倒排文件的方法,使用NEXI作为检索语言,在基于XML的数字图书馆检索实验系统WHU-XML上对其进行实现,并具体分析查询语言的解析方法以及所采用的结构化检索算法。 相似文献
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XML检索系统及其比较研究* 总被引：2，自引：0，他引：2
探讨XML检索与传统信息检索的区别、XML检索的目标与任务以及XML检索系统研究的核心问题,并对现有的几个XML检索系统进行介绍和比较研究。 相似文献
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重要句群是指最能表达文献主题的若干句子的集合,客观性强、生成效率高,可在利用自动文摘成果的基础上基于重要句群进行检索.在对句子进行预处理、文献语词权重计算以及句子权重计算后生成重要句群.利用基于向量模型的方法以及构建检索式和检索提问分别对基于文摘、重要句群和全文的检索性能进行对比分析.实验结果表明,基于重要句群的检索性能总体优于作者文摘,但是低于全文,可以将重要句群作为后台数据或搜索引擎的摘要等.句子级别的文本处理对提升文本检索效果的作用不大,而把文本处理提升至上下文的语义级别是可能的有效方法. 相似文献
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In this paper we evaluate the application of data fusion or meta-search methods, combining different algorithms and XML elements, to content-oriented retrieval of XML structured data. The primary approach is the combination of a probabilistic methods using Logistic regression and the Okapi BM-25 algorithm for estimation of document relevance or XML element relevance, in conjunction with Boolean approaches for some query elements. In the evaluation we use the INEX XML test collection to examine the relative performance of individual algorithms and elements and compare these to the performance of the data fusion approaches. 相似文献
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Query languages for XML such as XPath or XQuery support Boolean retrieval: a query result is a (possibly restructured) subset of XML elements or entire documents that satisfy the search conditions of the query. This search paradigm works for highly schematic XML data collections such as electronic catalogs. However, for searching information in open environments such as the Web or intranets of large corporations, ranked retrieval is more appropriate: a query result is a ranked list of XML elements in descending order of (estimated) relevance. Web search engines, which are based on the ranked retrieval paradigm, do, however, not consider the additional information and rich annotations provided by the structure of XML documents and their element names.This article presents the XXL search engine that supports relevance ranking on XML data. XXL is particularly geared for path queries with wildcards that can span multiple XML collections and contain both exact-match as well as semantic-similarity search conditions. In addition, ontological information and suitable index structures are used to improve the search efficiency and effectiveness. XXL is fully implemented as a suite of Java classes and servlets. Experiments in the context of the INEX benchmark demonstrate the efficiency of the XXL search engine and underline its effectiveness for ranked retrieval. 相似文献
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XML retrieval is a departure from standard document retrieval in which each individual XML element, ranging from italicized words or phrases to full blown articles, is a retrievable unit. The distribution of XML element lengths is unlike what we usually observe in standard document collections, prompting us to revisit the issue of document length normalization. We perform a comparative analysis of arbitrary elements versus relevant elements, and show the importance of element length as a parameter for XML retrieval. Within the language modeling framework, we investigate a range of techniques that deal with length either directly or indirectly. We observe a length-bias introduced by the amount of smoothing, and show the importance of extreme length bias for XML retrieval. We also show that simply removing shorter elements from the index (by introducing a cut-off value) does not create an appropriate element length normalization. Even after restricting the minimal size of XML elements occurring in the index, the importance of an extreme explicit length bias remains. 相似文献
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对信息检索系统返回结果相关度的改进,一直是信息检索领域重要的研究内容。本文首先引入查询词出现信息的概念,随后给出了查询词出现权重的形式化表示,进而将其与BM25模型结合起来。对于查询词出现权重的计算,本文采用了两种方法,即线性加权方法和因数加权方法。我们通过在GOV2数据集上的实验发现,无论哪种方法,通过加入查询词出现权重,都可以有效的改进检索结果的相关度。实验显示,对于TREC 2005的查询,MAP值的改进达到15.78%,p@10的改进达到3468%。本文所描述的方法已经应用到TREC 2009的WebTrack中。 相似文献
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This paper investigates the impact of three approaches to XML retrieval: using Zettair, a full-text information retrieval system; using eXist, a native XML database; and using a hybrid system that takes full article answers from Zettair and uses eXist to extract elements from those articles. For the content-only topics, we undertake a preliminary analysis of the INEX 2003 relevance assessments in order to identify the types of highly relevant document components. Further analysis identifies two complementary sub-cases of relevance assessments (General and Specific) and two categories of topics (Broad and Narrow). We develop a novel retrieval module that for a content-only topic utilises the information from the resulting answer list of a native XML database and dynamically determines the preferable units of retrieval, which we call Coherent Retrieval Elements. The results of our experiments show that—when each of the three systems is evaluated against different retrieval scenarios (such as different cases of relevance assessments, different topic categories and different choices of evaluation metrics)—the XML retrieval systems exhibit varying behaviour and the best performance can be reached for different values of the retrieval parameters. In the case of INEX 2003 relevance assessments for the content-only topics, our newly developed hybrid XML retrieval system is substantially more effective than either Zettair or eXist, and yields a robust and a very effective XML retrieval. 相似文献
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XML 语言在数字化图书馆系统中的应用 总被引：2，自引：0，他引：2
张菽 《现代图书情报技术》2002,18(6):7-9
介绍了如何在数字化图书馆系统中运用XML语言的方法。并且说明了XML语言的特性及它与HTML语言的区别。利用韩国虚拟图书馆和信息系统（VINIS）中的一个子系统——基于XML语言的元数据搜索的实验系统来演示XML用法。元数据检索系统包括两个模块：搜索模块和浏览模块。搜索模块允许对储存在Access文件中的元数据进行搜索并且可以用XML语言的形式显示搜索结果，浏览模块允许浏览以XMUXSL文件形式存在的元数据。文章最后讨论了如何在数字化图书馆中更有效的运用XML语言。 相似文献