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叙词在网络环境中的应用 总被引：1，自引：1，他引：1
本文叙述了叙词在网络环境下的三种应用模式，在一些专业性的网站以及网关检索系统中用叙词直接标引和检索是非常的普遍；叙词由于其概念定义明确，有很好的词问关系的显示，叙词能在基于关键词检索的搜索引擎中实现检索式的扩展的功能；不同部门对所拥有的资料和图书馆等信息源一般所采用的不同的叙词表或采用分类法，在网络环境下，通过一种主题的途径来检索这些信息是信息情报界研究的一个热点，叙词在这方面有着重要的作用。 相似文献
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《汉语主题词表》是我国情报检索语言发展历史中的一个里程碑。在网络时代,《汉语主题词表》将得到新的发展和应用。文章针对《汉语主题词表》的现状,回顾了它的编制和修订历史,其作为情报语言检索工具,在信息组织中发挥了重要作用。对如何在知识组织中发挥作用,如何在网络环境下构筑适应计算机环境的新型词表,向网络环境下的词系统推进,作者提出了新的发展思路和策略方法。 相似文献
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We report on the design and construction of features of an automated query system which will assist pharmacologists who are not information specialists to access the Derwent Drug File (DDF) pharmacological database. Our approach was to first elucidate those search skills of the search intermediary which might prove tractable to automation. Modules were then produced which assist in the three important subtasks of search statement generation, namely vocabulary selection, the choice of context indicators and query reformulation. Vocabulary selection is facilitated by approximate string matching, morphological analysis, browsing and menu searching. The context of the study, such as treatment or metabolism, is determined using a system of advisory menus. The task of query reformulation is performed using user feedback on retrieved documents, thesaurus relations between document index terms and term postings data. Use is made of diverse information sources, including electronic forms of printed search aids, a thesaurus and a medical dictionary. The system will be of use both to semicasual users and experienced intermediaries. Many of the ideas developed should prove transportable to domains other than pharmacology: the techniques for thesaurus manipulation are designed for use with any hierarchical thesaurus. 相似文献
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Direct end-user data entry and retrieval is a major factor in achieving an economical information retrieval system. To be effective, such a system would have to provide a thesaurus structure which leads novice end-users to browse subject areas before retrieval and yet provides control and coverage of terms in a domain. A faceted hierarchical thesaurus organization has been designed to accomplish this goal. 相似文献
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本文介绍了支持虚拟资源透明检索的词表转换的三种主要转换方法，多语言词表方式，一对一映射方式和总体词表方式，举例说明了后两者的实现形式和问题。 相似文献
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Following a general discussion on the philosophy and design of information systems, with particular attention to the definition, needs and psychology of the ultimate user of systems providing on-line access to biomedical information, the role of the documentalist, the differences between document retrieval and true information retrieval and the operational characteristics of on-line systems which affect their cost and hence their design and acceptability, the authors make some tentative predictions as to the future demand for such information retrieval services and their probable organizational form. A brief report is then presented on the principal findings and conclusions of a user's study of the Excerpta Medica system, the key features and history of which are briefly described. Based on the conclusions of this study, particularly as regards the complexity of the average search question, the role of the search formulators in determining the results of computer searching, the importance of secondary concepts for retrieval and the optimal level of specificity of a computer thesaurus, some of the changes in the Excerpta Medica system which are in the planning stage and will be incorporated into the system's Mark II version are outlined, as are the principal features of the two systems currently offering on-line access to the Excerpta Medica database in Western Germany and the U.S.A. Finally, attention is given to the planned partial hierarchic structuring of the Excerpta Medica thesaurus (Malimet), a project which is to be based largely on frequency counts of the existing database and the elimination of over-specific terms by posting under broader concepts. The results of some of the initial steps in this direction (i.e. frequency counts of portions of the database and the structuring of some of the terms used in the cancer field) are presented by way of illustration. 相似文献
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Several experiments were conducted at the Documentation Research and Training Centre for generating thesaurus. The work reported in this paper, uses subject headings structured according to postulates and principles for facet analysis, as the input for generating thesaurus. The system uses a coding scheme for augmenting the subject headings to make them suitable for computer manipulation. Once the subject headings are coded and input, the other processes are done automatically. The system has five phases namely, Translation Phase, Term-pair Generation Phase, Coordinate Term-pair Generation Phase, Retranslation Phase and Printing Phase. The system is described briefly, giving the systems flow-chart, inputs and outputs of the different phases and a sample printout of a model thesaurus generated using test data of about 1500 subject-propositions from Leather Technology. 相似文献
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Gerhard H. R. Reisig 《Information processing & management》1978,14(6):405-417
Information-systems are classified into two types, termed “Evidence-of Existence” and “Presentation” of information. The objective of the evidence-type system lies in the domain of documentation and retrieval of information. The structure of this system-type is developed, with application of cybernetic concepts, as an isomorphic model in analogy to the system-structure of communication technology. The latter postulates three criteria of structuring: (1) Source-Channel-Sink, with input-output characteristics, (2) Filter-type communication-channel, (3) Reversable code. These criteria are applied to the structuring of information-systems of the evidence-of-existence type. For the purpose of two-way communication the information-systems have to be represented by closed-loop models. The selective-retrieval requirements necessitate the system-channel to be a filter of information. These information-filters are implemented by keyword-phrases, being identical with the codewords. They yield a uniquely decodable code which is totally reversible to adequately serve both the documentation and the retrieval of documents. It is proven that hierarchic information-systems, applying categorization or subject-heading objects of information, do not meet the mandatory code-requirements. The inherent coding-deficiencies of hierarchic systems generate intolerable retrieval ambiguities. The same critique applies to the thesaurus concept. The development of a novel species of thesaurus is suggested, realizing a kind of Linnéan encyclopedia of general human knowledge, presenting all relevant interrelations of objects of knowledge. Such thesaurus would provide the much needed support for formulating efficient search queries. Other relevant features of communication technology, like the information-potential, should be isomorphically transformed into information-system models. 相似文献
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基于聚类的词表等级关系自动识别研究 总被引：3，自引：0，他引：3
词汇等级关系的识别是自动构建叙词表的重点和难点之一.基于相似度的词聚类方法,突破了按字面聚集等级关系词汇的传统做法的局限性,能够深入语义,识别出字面上无此特点的等级关系词汇.介绍了该方法并进行测试,试验结果表明该方法具有一定可行性. 相似文献
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词表是图书馆和信息检索领域最重要的知识组织工具,《中国分类主题词表》是传统词表的一种,它的更新和维护一直依靠手工进行,这制约了它在数字图书馆和网络信息环境下的应用。本文介绍了一项基于统计的、从元数据的标题中抽取关键词并定位在词表中的方法。大致包括三个步骤:从标题中提取关键词;确定抽取出的关键词的专指度;将专指度高的专业词汇定位在词表中。在《中国分类主题词表》和上海图书馆提供的计算机科技领域的元数据上所进行实验,结果证明该方法是可行的。这一方法可以应用到自动标引或编目中,有一定的实用性和广阔的应用前景。 相似文献
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全文检索研究 总被引：11，自引：0，他引：11
A new algorithm for automatic segmentation of Chinese word with the stop word list and post-controlled thesaurus, that has absorbed the ideas from the single-Chinese character method and the thesaurus method, is given. Based on this algorithm, a new full text retrieval mode is built. 相似文献
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Decisions in thesaurus construction and use 总被引：1，自引：0，他引：1
A thesaurus and an ontology provide a set of structured terms, phrases, and metadata, often in a hierarchical arrangement, that may be used to index, search, and mine documents. We describe the decisions that should be made when including a term, deciding whether a term should be subdivided into its subclasses, or determining which of more than one set of possible subclasses should be used. Based on retrospective measurements or estimates of future performance when using thesaurus terms in document ordering, decisions are made so as to maximize performance. These decisions may be used in the automatic construction of a thesaurus. The evaluation of an existing thesaurus is described, consistent with the decision criteria developed here. These kinds of user-focused decision-theoretic techniques may be applied to other hierarchical applications, such as faceted classification systems used in information architecture or the use of hierarchical terms in “breadcrumb navigation”. 相似文献
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Authors and searchers usually express the same things in many different ways, which causes problems in free text searching of text databases. Thus, a switching tool connecting the different names of one concept is needed. This study tests the effectiveness of a thesaurus as a search-aid in free text searching of a full text database. A set of queries was searched against a large full text database of newspaper articles. The search-aid thesaurus constructed for the test contains the usual relationships of a thesaurus, namely equivalence, hierarchical, and associative relationships. Each query was searched in five distinct modes: basic search, synonym search, narrower term search, related term search, and union of all previous searches. The basic searches contained only terms included in the original query statements. In the synonym searches, the terms of the basic search were extended by disjunction of the synonyms given by the search-aid thesaurus without modifying the overall logic of the basic search. Likewise, the basic search was extended in turn with the narrower terms and with the related terms given by the search-aid thesaurus. The last search mode included the basic terms and all the terms used in the previous searches. The searches were analyzed in terms of relative recall and precision; relative recall was estimated by setting the recall of the union search to 100%. On the average the value of relative recall was 47.2% in the basic search, compared with 100% in the union search; the average value of precision decreased only from 62.5% in the basic search to 51.2% in the union search. 相似文献
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Tadeusz Radecki 《Information processing & management》1977,13(2):109-116
Search patterns of documents and information requests are their better or worse representatives only, so it is important to carry on examinations on possibilities of designing self-learning information retrieval systems. Another important question is to elaborate such an organization of document search pattern set as to obtain an acceptable response time of the information system to a given information request.A self-learning process of the proposed information system consists in the determination—on a set of document and information request search patterns—of the similarity relation according to L. A. Zadeh.The organization of a set of document search patterns proposed in the paper ensures the limitation of document search pattern set searching process—when retrieving a response to a given information request—to one (or several) subset from previously determined subsets. This makes the information system response time acceptable. The proposed information retrieval strategy is discussed in terms of fuzzy sets. 相似文献
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本文分析传统书刊索引的知识揭示和定位功能,指出利用信息组织技术编制书刊索引可提高索引的质量和效率,保证丛书索引的一致性,并为复合出版的知识服务打下基础.基于上述思路,本文通过原型系统对中华人民共和国史领域的丛书索引进行实践. 相似文献