共查询到20条相似文献,搜索用时 109 毫秒
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主要研究基于XML的数据集成中介器系统,继承传统的包装器/中介器架构模式,在多个分布式异构数据源上构建全局统一视图,以XQuery为查询语言,提供对外统一访问接口;并应用于集成异构科技数据源,整合离散科学数据资源,实现时科技数据资源的规范化管理和高效利用. 相似文献
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基于本体的信息集成框架中包装器的设计 总被引:1,自引:0,他引:1
将本体应用在信息集成框架中能够在语义层次上消除底层数据源的异构,但是本体只相当于一个知识库,在定义用户接口时,需要赋予其一个语法结构,这个语法结构可作为与用户交互的全局模式,从本体到全局模式的转换可以用包装器来实现。而此全局模式和各个数据源之间的局部模式也需要映射,这些映射也可以用包装器来实现。该文提出了基于本体的信息集成框架中一种包装器的设计,通过将本体转换为XMLSchema作为全局模式,并利用XSLT实现全局模式和局部模式的映射,从而屏蔽了数据源的异构性。 相似文献
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在Web应用环境中,可以通过RDF(S)形式描述企业领域内分布信息资源的语义,以提高信息查询的准确性.提出了描述分布异构RDF(S)的分布RDF(S)模型,并基于这一模型给出了实现分布RDF(S)查询的方法,此查询方法既能实现实例层次的查询,也能实现概念层次的查询.基于这一方法,用户能够以统一的形式来查询,获取相关的信息资源,同时还可以实现分布RDF(S)的集成. 相似文献
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开发Web信息抽取系统的核心是为各个Web信息源构造包装器,而构造包装器的关键在于规则学习器。鉴于传统的规则学习器一般都基于单一的学习策略,结合归纳学习和分析学习的优点,提出了基于解释学习的规则学习器,以此为核心生成包装器,并将其应用到了实际的包装器生成系统中去。 相似文献
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计算机网络的迅猛发展使企业内部数据交换越来越频繁,然而,系统实现技术及实现时间上的差异造成了在不同的信息系统中存在着大量异构数据.异构数据源的存在给实现不同信息系统间数据互访带来了很大的不便.为了解决异构数据源共享和部署集成平台过于复杂的问题,在充分调研国内外信息集成文献的基础上,基于XML和Web Service技术实现了一个新型的异构数据集成平台.该平台采用XML文件存储元数据,部署时无需新建数据库,实现了轻量级部署;将中介器和包装器发布成Web Service,支持多种集成平台客户端; 该平台能够屏蔽网络、操作系统、各种关系型数据库、XML文件的异构性,支持企业集成历史遗留数据、发布信息,并具有高度灵活性、轻便性和可重用性. 相似文献
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ITS虚拟共用信息平台的数据集成包装器 总被引:1,自引:0,他引:1
针对ITS虚拟共用信息平台各子系统数据异构、分布存储的特点,采用异构数据集成模型,探讨了ITS虚拟共用信息平台的数据集成方案,并结合ITS虚拟共用信息平台的体系结构,设计了ITS虚拟共用信息平台的数据集成包装器,并对包装器时间中的关键技术以及包装器的具体实现过程进行了详细说明。 相似文献
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基于Web服务统一检索系统的设计 总被引:3,自引:0,他引:3
通过分析目前数字图书馆统一检索方法,利用Web Services技术,对传统异构数据源集成方法Mediator/WrapPer进行改进,提出一个基于Web Services统一检索方案,以Web服务注册机制代替虚拟视图,在包装器上增加web服务封装及发布功能,构建资源透明访问框架,实现对分布式异构数字图书馆资源的统一检索. 相似文献
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张骞 《自动化与仪器仪表》2014,(8):15-16
在实现个人数字图书馆的信息检索的时候,如果能有效的综合网格P2P技术以及Z39.50技术并加以利用的话,这会对信息检索的实现策略更加的优秀.但是网格P2P技术与Z39.50技术目前还不能直接结合,它们之间的结合需要由一个桥梁来完成,这个桥梁就是中间件技术.本文对基于网格的个人数字图书馆信息检索策略进行了研究,对个人数字图书馆信息检索策略建设具有一定意义. 相似文献
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《Computer Standards & Interfaces》2002,24(4):291-309
Given the ever-increasing scale and diversity of information and applications on the Internet, improving the technology of information retrieval is an urgent research objective. Retrieved information is either semi-structured or unstructured in format and its sources are extremely heterogeneous. In consequence, the task of efficiently gathering and extracting information from documents can be both difficult and tedious. Given this variety of sources and formats, many choose to use mediator/wrapper architecture (Y. Papakonstantinou, A. Gupta, H. Garcia-Molina, J. Ullman, A Query Translation Scheme for Rapid Implementation of Wrappers, International Conference on Deductive and Object-Oriented Databases, Singapore, 1995), but its use demands a fast means of generating efficient wrappers.In this paper, we present a design for an automatic eXtensible Markup Language (XML)-based framework with which to generate wrappers rapidly. Wrappers created with this framework support a unified interface for a meta-search information retrieval system based on the Internet Search Service using the Common Object Request Broker Architecture (CORBA) standard. Greatly advantaged by the compatibility of CORBA and XML, a user can quickly and easily develop information-gathering applications, such as a meta-search engine or any other information source retrieval method. The two main things our design provides are a method of wrapper generation that is fast, simple, and efficient, and a wrapper generator that is CORBA and XML-compliant and that supports a unified interface. 相似文献
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高校数字图书馆元数据检索系统的设计与实现 总被引:10,自引:0,他引:10
结合承担某高校数字图书馆建设工程项目背景,详细分析了元数据的重要性和都柏林核心数据的特点,提出了高校数字图书馆信息检索系统总的设计思想和统一资源检索模型,最后设计出了数字资源的元数据结构和基于元数据的检索系统。 相似文献
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An XML-enabled data extraction toolkit for web sources 总被引:7,自引:0,他引:7
The amount of useful semi-structured data on the web continues to grow at a stunning pace. Often interesting web data are not in database systems but in HTML pages, XML pages, or text files. Data in these formats are not directly usable by standard SQL-like query processing engines that support sophisticated querying and reporting beyond keyword-based retrieval. Hence, the web users or applications need a smart way of extracting data from these web sources. One of the popular approaches is to write wrappers around the sources, either manually or with software assistance, to bring the web data within the reach of more sophisticated query tools and general mediator-based information integration systems. In this paper, we describe the methodology and the software development of an XML-enabled wrapper construction system—XWRAP for semi-automatic generation of wrapper programs. By XML-enabled we mean that the metadata about information content that are implicit in the original web pages will be extracted and encoded explicitly as XML tags in the wrapped documents. In addition, the query-based content filtering process is performed against the XML documents. The XWRAP wrapper generation framework has three distinct features. First, it explicitly separates tasks of building wrappers that are specific to a web source from the tasks that are repetitive for any source, and uses a component library to provide basic building blocks for wrapper programs. Second, it provides inductive learning algorithms that derive or discover wrapper patterns by reasoning about sample pages or sample specifications. Third and most importantly, we introduce and develop a two-phase code generation framework. The first phase utilizes an interactive interface facility to encode the source-specific metadata knowledge identified by individual wrapper developers as declarative information extraction rules. The second phase combines the information extraction rules generated at the first phase with the XWRAP component library to construct an executable wrapper program for the given web source. 相似文献
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数字图书馆信息检索技术及其应用 总被引:2,自引:0,他引:2
从数字图书馆的发展现状展开研究,对数字图书馆与传统图书馆进行了比较,分析了信息检索概念和技术。介绍了CBR的特点,重点阐述了数字图书馆多媒体检索技术分类及各自特点,明确指出了数字图书馆建设的意义、应用中存在的问题,展望了数字图书馆的前景。 相似文献
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Browsing and searching are two prominent paradigms in information retrieval. In the current digital library implementations, exploratory browsing is either not available as an option or commonly presented as an alphabetical listing of chosen categories depending on the scope of the digital collections. In addition, users have to switch between different information spaces for browsing and searching. This research proposes an information retrieval paradigm of integrated faceted browser and direct search interfaces for text-based digital libraries. Experimental results show that compared to a conventional alphabetical browser, the faceted browser can significantly improve the effectiveness (by 30.8%, p = .015) and efficiency (by 11.3%, p = .001) of information retrieval. Also, compared to un-integrated alphabetical browser with direct search interfaces, the integrated faceted browser with direct search interfaces can significantly improve the effectiveness of information retrieval (by 35.7%, p = .03) and bring users greater satisfaction (by 34.8%, p < .03) with the process. 相似文献
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A. N. Bezdushnyi A. B. Zhizhchenko M. V. Kulagin V. A. Serebryakov 《Programming and Computer Software》2000,26(4):177-185
Problems of developing digital libraries are considered. An analysis of this class of distributed information systems is given.
The main effort is focused on the formalization of properties of the stored objects and operations, which makes it possible
to construct a formal model of digital libraries. This model can serve as a basis for designing development tools. Systems
based on this approach are called integrated information resource systems (IIRS). In particular, the information retrieval
system of the Russian Academy of Sciences (IIRS RAS) is based on these principles. The paper is organized as follows. First,
the aim of the paper is outlined. Then, the definition of a digital library is given (as it is understood by the authors),
basic concepts are discussed, and IIRS is considered as a digital library. The notion of the resource is introduced as the
basic object to be processed. Metadata and their role in the system of digital libraries are considered, as well as the role
of relationships and data organization. Then, the architecture and functional capabilities of IIRS are considered, and, in
particular, a metamodel of the system, data search, and the implementation of data distribution. The current implementation
of IIRS RAS is briefly outlined. 相似文献
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基于Jena规则推理数字图书馆信息检索系统研究 总被引:1,自引:1,他引:0
数字图书馆的核心任务之一就是提供良好的信息检索系统,而传统的信息检索技术以关键字匹配为主,缺乏语义推理能力,对用户的查询请求没有提供语义指导,因此造成信息的误检、漏检。将Jena用于数字图书馆信息检索,首先分析了数字图书馆的特点和需求,接着提出了基于Jena数字图书馆信息检索模型,深入研究了关键技术,最后对研究进行了验证。 相似文献
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《Information & Management》2002,39(4):255-260
This paper presents the results of my action research. I was involved in establishing and running a digital library that was founded by the government of South Korea. The process involved understanding the relationship between the national IT infrastructure and the success factors of the digital library. In building, the national IT infrastructure, a digital library system was implemented; it combines all existing digitized university libraries and can provide overseas information, such as foreign journal articles, instantly and freely to every Korean researcher. An empirical survey was made as a part of the action research; the survey determined user satisfaction in the newly established national digital library. After obtaining the survey results, I suggested that the current way of running the nationwide government-owned digital library should be retained. 相似文献