共查询到20条相似文献,搜索用时 375 毫秒
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提出了一种新的基于贝叶斯网络对XML文档信息进行查询的模型方法.该模型支持针对XML文档信息的结构化查询.基于XML信息查询的特点,利用XML数据集中语词、元素和结构化单元的统计信息对模型的拓扑结构和条件概率进行了学习;结合概率函数的方法,利用模型的概率推理进程对XML文档和结构化查询条件的相关度进行了估算.最后在基于INEX测试集的实验中证明了该方法的有效性和可靠性. 相似文献
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用户界面友好的XML查询方案 总被引:10,自引:0,他引:10
提出一用户界面友好的XML文档查询方案,使普通Internet用户不必使用复杂的XML查询语言,也不必知道所查XML文档的精确结构,只须输入相关的已知条件和待求信息,就能够实现Web上XML文档的统一查询。 相似文献
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高效地开发软件界面是提高整个软件开发效率的关键.为了提升界面开发效率、降低软件开发成本,针对B/S结构的系统,提出了基于XML Schema的Web界面生成方法.根据FDP模型生成XML Schema界面描述文档,将Schema文档组织成文档库;同时建立样式模板库,对它们统一管理实现文档复用.通过XML Schema-to-HTML转换方法,实现了由界面描述文档自动生成Web界面,并利用XML Schema对界面输入数据直接验证.该方法可以较规范地描述界面,提升界面开发效率,并实现界面生成与界面验证的集成. 相似文献
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贝叶斯网络检索模型可以表示术语间的条件概率和概念语义,并依此预测用户查询和文档间的相似度,是解决信息检索的有效手段。通过构造中文测试集合,对简单贝叶斯网络检索模型和扩展的贝叶斯网络检索模型的性能进行详细评估,实验证明扩展模型可以有效地提高检索性能,在一定程度上实现了基于语义的信息检索。 相似文献
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在网络管理系统中存在大量的配置管理界面,为每一个配置管理界面编写专门的代码是一项繁杂、重复性的工作。文章提出一种基于XML的网管系统界面自动生成技术,通过实例阐述了界面描述的XML文档格式、组件事件处理方法和界面生成器的实现方案。该技术能大大提高用户界面的开发效率,并增强软件的可维护性。 相似文献
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由于半结构文档如XML越来越广泛的应用,在数据库和信息检索领域,对半结构XML数据相似度的研究也变得尤为重要。给定XML文档集D和用户查询q,XML检索即是从D中查找出符合q的XML文档。为了有效地进行XML信息检索,提出了一种新的计算用户查询与XML文档之间相似度的算法。该算法分为三步:基于WordNet对用户查询q进行同义词扩展得到q';将q'和D中的每一篇XML文档都进行数字签名,并通过签名之间的匹配对D进行有效过滤,除去大量不符合用户查询的文档,得到一个文档子集D',[D'?D];对q'与D'中的文档进行精确匹配得到检索结果。 相似文献
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In the course of network supported collaborative design, the data processing plays a very vital role. Much effort has been spent in this area, and many kinds of approaches have been proposed. Based on the correlative materials, this paper presents extensible markup language(XML)based strategy for several important problems of data processing in network supported collaborative design, such as the representation of standard for the exchange of product model data(STEP)with XML in the product information expression and the management of XML documents using relational database. The paper gives a detailed exposition on how to clarify the mapping between XML structure and the relationship database structure and how XML-QL queries can be translated into structured query language(SQL) queries. Finally, the structure of data processing system based on XML is presented. 相似文献
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Dunren Che Karl Aberer M. Tamer Özsu 《The VLDB Journal The International Journal on Very Large Data Bases》2006,15(3):263-289
While the information published in the form of XML-compliant documents keeps fast mounting up, efficient and effective query
processing and optimization for XML have now become more important than ever. This article reports our recent advances in
XML structured-document query optimization. In this article, we elaborate on a novel approach and the techniques developed
for XML query optimization. Our approach performs heuristic-based algebraic transformations on XPath queries, represented
as PAT algebraic expressions, to achieve query optimization. This article first presents a comprehensive set of general equivalences
with regard to XML documents and XML queries. Based on these equivalences, we developed a large set of deterministic algebraic
transformation rules for XML query optimization. Our approach is unique, in that it performs exclusively deterministic transformations
on queries for fast optimization. The deterministic nature of the proposed approach straightforwardly renders high optimization
efficiency and simplicity in implementation. Our approach is a logical-level one, which is independent of any particular storage
model. Therefore, the optimizers developed based on our approach can be easily adapted to a broad range of XML data/information
servers to achieve fast query optimization. Experimental study confirms the validity and effectiveness of the proposed approach. 相似文献
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针对传统的信息检索方法无法实现用户查询的语义理解、检索效率低等问题,本文提出基于领域本体进行查询扩展的贝叶斯网络检索模型。该模型首先将用户查询通过领域本体进行语义扩展,然后将扩展后的查询作为证据在贝叶斯网络检索模型中进行传播,进而得到查询结果,实验表明本文提出的贝叶斯网络检索模型能提高检索效率。 相似文献
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XML has been recognized as a promising language for data exchange over the Internet. A number of query languages have been proposed for querying XML data. Most of those languages are path-expression based. One difficulty in forming path-expression based queries is that users have to know the structure of XML data against which the queries were issued. In this paper, we describe a DTD-driven visual query interface for XML database systems. With such an interface, a user can easily form path-expression based queries by clicking elements in the DTD tree displayed on the screen and supplying conditions if necessary. The interface and the query generation process are described in detail. 相似文献
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Rao Praveen R. Moon Bongki 《Knowledge and Data Engineering, IEEE Transactions on》2009,21(12):1737-1752
One of the key challenges in a peer-to-peer (P2P) network is to efficiently locate relevant data sources across a large number of participating peers. With the increasing popularity of the extensible markup language (XML) as a standard for information interchange on the Internet, XML is commonly used as an underlying data model for P2P applications to deal with the heterogeneity of data and enhance the expressiveness of queries. In this paper, we address the problem of efficiently locating relevant XML documents in a P2P network, where a user poses queries in a language such as XPath. We have developed a new system called psiX that runs on top of an existing distributed hashing framework. Under the psiX system, each XML document is mapped into an algebraic signature that captures the structural summary of the document. An XML query pattern is also mapped into a signature. The query's signature is used to locate relevant document signatures. Our signature scheme supports holistic processing of query patterns without breaking them into multiple path queries and processing them individually. The participating peers in the network collectively maintain a collection of distributed hierarchical indexes for the document signatures. Value indexes are built to handle numeric and textual values in XML documents. These indexes are used to process queries with value predicates. Our experimental study on PlanetLab demonstrates that psiX provides an efficient location service in a P2P network for a wide variety of XML documents. 相似文献
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Searching XML data with a structured XML query can improve the precision of results compared with a keyword search. However, the structural heterogeneity of the large number of XML data sources makes it difficult to answer the structured query exactly. As such, query relaxation is necessary. Previous work on XML query relaxation poses the problem of unnecessary computation of a big number of unqualified relaxed queries. To address this issue, we propose an adaptive relaxation approach which relaxes a query against different data sources differently based on their conformed schemas. In this paper, we present a set of techniques that supports this approach, which includes schema-aware relaxation rules for relaxing a query adaptively, a weighted model for ranking relaxed queries, and algorithms for adaptive relaxation of a query and top-k query processing. We discuss results from a comprehensive set of experiments that show the effectiveness and the efficiency of our approach. 相似文献
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Web数据集成系统基于QC模型的物化视图选择 总被引:2,自引:0,他引:2
在Web数据集成系统中,物化视图能够有效地减少网络传输代价,提高系统的查询效率.如何选择查询进行物化,使得选中的查询满足集成层的空间限制,同时获取最大物化收益,成为集成系统中一个迫切需要解决的问题.传统方法没有考虑到海量XML查询之间的包含关系,其选择的物化视图中可能包含冗余的信息.针对上述问题,提出了①Web数据集成系统中海量查询集合的QC(query containment)模型,该模型能够捕捉查询之间最常见的包含关系;②基于QC模型的物化视图选择算法,算法考虑了物化视图选择相关的主要因素,包括查询提交的频率、空间代价、查询重写能力和查询结果的完备性,提出了查询位图的物化视图组织方式,从而获取更加合理的物化视图选择方案.实验结果证明了该方法的有效性. 相似文献