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中文全文检索技术的研究及实现 总被引：9，自引：0，他引：9
本文设计了一个中文全文检索系统 ,在单汉字全文数据库的基础之上进行了全文检索的算法研究 ,提出了针对特定检索策略的计算公式。同时还对检索结果集的排序问题进行了讨论 ,并采用用户反馈信息量 ,使最后检出的结果在应用中不断得到优化 相似文献
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Deurenberg R Vlayen J Guillo S Oliver TK Fervers B Burgers J;SEARCH Group 《Health information and libraries journal》2008,25(1):23-30
BACKGROUND: Effective literature searching is particularly important for clinical practice guideline development. Sophisticated searching and filtering mechanisms are needed to help ensure that all relevant research is reviewed. PURPOSE: To assess the methods used for the selection of evidence for guideline development by evidence-based guideline development organizations. METHODS: A semistructured questionnaire assessing the databases, search filters and evaluation methods used for literature retrieval was distributed to eight major organizations involved in evidence-based guideline development. RESULTS: All of the organizations used search filters as part of guideline development. The medline database was the primary source accessed for literature retrieval. The OVID or SilverPlatter interfaces were used in preference to the freely accessed PubMed interface. The Cochrane Library, embase, cinahl and psycinfo databases were also frequently used by the organizations. All organizations reported the intention to improve and validate their filters for finding literature specifically relevant for guidelines. DISCUSSION: In the first international survey of its kind, eight major guideline development organizations indicated a strong interest in identifying, improving and standardizing search filters to improve guideline development. It is to be hoped that this will result in the standardization of, and open access to, search filters, an improvement in literature searching outcomes and greater collaboration among guideline development organizations. 相似文献
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广东高校图书馆文献信息网络系统 总被引：3，自引：0，他引：3
毛卓明 《现代图书情报技术》1999,15(4):29-31
简要地叙述了“广东高校图书馆文献信息网络系统(NULOG)”的立项背景。论述了系统的建设目标,实际地描述了目前系统进展的状况,包括系统的网络状况、硬件配置、系统软件和数据库系统及开发工具、应用系统开发及应用系统特点、系统中数据库建设的规模。提出了今后系统建设进一步地设想和目标。 相似文献
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Vreixo Formoso Diego Fernández Fidel Cacheda Victor Carneiro 《Information Retrieval》2013,16(6):680-696
Collaborative filtering is a popular recommendation technique. Although researchers have focused on the accuracy of the recommendations, real applications also need efficient algorithms. An index structure can be used to store the rating matrix and compute recommendations very fast. In this paper we study how compression techniques can reduce the size of this index structure and, at the same time, speed up recommendations. We show how coding techniques commonly used in Information Retrieval can be effectively applied to collaborative filtering, reducing the matrix size up to 75 %, and almost doubling the recommendation speed. Additionally, we propose a novel identifier reassignment technique, that achieves high compression rates, reducing by 40 % the size of an already compressed matrix. It is a very simple approach based on assigning the smallest identifiers to the items and users with the highest number of ratings, and it can be efficiently computed using a two pass indexing. The usage of the proposed compression techniques can significantly reduce the storage and time costs of recommender systems, which are two important factors in many real applications. 相似文献
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Computational modelling of music similarity is an increasingly important part of personalisation and optimisation in music information retrieval and research in music perception and cognition. The use of relative similarity ratings is a new and promising approach to modelling similarity that avoids well known problems with absolute ratings. In this article, we use relative ratings from the MagnaTagATune dataset with new and existing variants of state-of-the-art algorithms and provide the first comprehensive and rigorous evaluation of this approach. We compare metric learning based on support vector machines (SVMs) and metric-learning-to-rank (MLR), including a diagonal and a novel weighted variant, and relative distance learning with neural networks (RDNN). We further evaluate the effectiveness of different high and low level audio features and genre data, as well as dimensionality reduction methods, weighting of similarity ratings, and different sampling methods. Our results show that music similarity measures learnt on relative ratings can be significantly better than a standard Euclidian metric, depending on the choice of learning algorithm, feature sets and application scenario. MLR and SVM outperform DMLR and RDNN, while MLR with weighted ratings leads to no further performance gain. Timbral and music-structural features are most effective, and all features jointly are significantly better than any other combination of feature sets. Sharing audio clips (but not the similarity ratings) between test and training sets improves performance, in particular for the SVM-based methods, which is useful for some applications scenarios. A testing framework has been implemented in Matlab and made publicly available http://mi.soi.city.ac.uk/datasets/ir2012framework so that these results are reproducible. 相似文献
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Lynda Ayiku Thomas Hudson Ceri Williams Paul Levay Catherine Jacob 《Journal of the Medical Library Association》2021,109(4):583
Objective:We previously developed draft MEDLINE and Embase (Ovid) geographic search filters for Organisation for Economic Co-operation and Development (OECD) countries to assess their feasibility for finding evidence about the countries. Here, we describe the validation of these search filters.Methods:We identified OECD country references from thirty National Institute for Health and Care Excellence (NICE) guidelines to generate gold standard sets for MEDLINE (n=2,065) and Embase (n=2,023). We validated the filters by calculating their recall against these sets. We then applied the filters to existing search strategies for three OECD-focused NICE guideline reviews (NG103 on flu vaccination, NG140 on abortion care, and NG146 on workplace health) to calculate the filters'' impact on the number needed to read (NNR) of the searches.Results:The filters both achieved 99.95% recall against the gold standard sets. Both filters achieved 100% recall for the three NICE guideline reviews. The MEDLINE filter reduced NNR from 256 to 232 for the NG103 review, from 38 to 27 for the NG140 review, and from 631 to 591 for the NG146 review. The Embase filter reduced NNR from 373 to 341 for the NG103 review, from 101 to 76 for the NG140 review, and from 989 to 925 for the NG146 review.Conclusion:The NICE OECD countries'' search filters are the first validated filters for the countries. They can save time for research topics about OECD countries by finding the majority of evidence about OECD countries while reducing search result volumes in comparison to no filter use. 相似文献
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在新媒体时代,广播音乐节目受到了新媒体的强劲冲击。内容为王,广播音乐节目必须在内容上充分发掘自身的优势与不可替代性,提供独具观点、深度整合及可共享的音乐节目,方能在新旧媒体混战中立于不败之地。 相似文献
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基于传统文本检索系统的XML索引实现研究 总被引：3，自引：0，他引：3
作为重要的信息交换与存储标准,XML得到学者们越来越多的重视。作为XML检索研究的重要组成部分,XML索引机制与实现的研究已经取得了一定的研究成果。然而,大部分研究都是基于数据库及专门的半结构化管理器之上的。本文提出了如何在传统文本检索系统Okapi的基础上构建XML索引的方法。首先介绍了Okapi的索引结构,在此基础上,深入探讨了XML索引的存储结构及实现,并对索引的性能进行了评价。 相似文献
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王兰成 《现代图书情报技术》1995,11(5):7-9
本系统对任意数据库选定范围内的长字符型字段, 选取汉字特征抽取法等多种方法进行有效压缩, 并以压缩字段实现准确的快检数据库, 输出各种压缩方案、检索结果及结论信息, 以备查选优。 相似文献
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本文根据人文信息的数据类型及其独特性, 讨论了多媒体技术在人文信息处理中的若干具体问题。设计了一个包括全文, 诗词、曲、赋、图象、音乐等不同类型人文信息的多媒体应用数据库系统逻辑模型框架, 以期对利用多媒体技术建立人文信息服务系统起指导作用。 相似文献
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《Journal of Media Economics》2013,26(3):21-36
In 1996 French radio stations began complying with loi Carignon that sets a minimum quota of 40% of music time for French-language chansons. The law represents a departure from previous voluntary efforts to promote French-language music in broadcasting, but I argue that it is an example of political continuity in the protectionist tendencies discernible in French media policy. This article explores the reasons for the creation of the law, including political factors, career desires, and French media and cultural policies. 相似文献
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现场图书采购查重几种实现方式的比较 总被引：2，自引：0，他引：2
系统地分析了现场图书采购查重的三种实现方式,即传统现场图书采购查重方式,备份数据库查重方式和远程登录系统查重方式,指出了每种方式存在的优点、缺点,在进行比较与分析的基础上,探讨了现场图书采购查重方式的发展趋势,并指出查重设备最终必将向着体积小、质量轻、功能多的掌上计算机方向发展。 相似文献
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[目的/意义]针对目前使用标签推荐方法所得结果不理想的问题,改进传统相似度计算方式,并结合多种标签推荐方法,提高推荐准确性。[方法/过程]融合基于内容与协同过滤的推荐思想,利用LDA进行相似度计算得出资源与用户的近邻集合,并抽取资源内容关键词,以此构建标签混合推荐模型,最后以"豆瓣读书"为例对模型进行验证,同时与几种标签推荐方法进行比较。[结果/结论]在社会标注系统中,必须考虑用户-资源-标签3个维度,仅考虑单一角度势必会造成结果的不完整,同时在相似度计算时引入LDA能够挖掘潜在语义关系,提高推荐质量,且组合多种方法取长补短可以令推荐结果更为满意。 相似文献
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Alcina Cortez 《Curator: The Museum Journal》2016,59(2):153-176
Popular music is deeply embedded in the dynamics of the contemporary world by means of its capacity to engender modes of privacy and publicness, to communicate emotion, and to enable us to create connections—and so to work within communities. Museums have traditionally addressed art‐music through the exhibition of musical instruments. But now that the exhibition of popular music has presented new challenges and opportunities worldwide for museum professionals, examining popular music discourses in museums is of the utmost importance in order for it to be meaningfully celebrated as instances of heritage. This paper expands on the representation of Popular Music in museums in Portugal at the beginning of the twenty‐first century by discussing a case study: the exhibition No Tempo do Gira‐Discos: Um Percurso Pela Produção Fonográfica Portuguesa at Museu Nacional da Música, Lisbon, Portugal, in 2007. Two methods of analysis are deployed: interviews with the curators, which revealed insights on their understanding of popular music, and analysis of the exhibition through discourse analysis, specifically through the lens of the analytical concepts genre and register. Although the curators had themselves previously developed insightful and innovative concepts with regard to popular music, discourse analysis reveals how, in this instance, the museum practices were primarily inherited from past traditions, and so failed to convey the meanings previously envisioned by the curators. In order for genuine public engagement with museum exhibitions about music, a collaboration is required between the music studies and museum studies professionals. Only through such a collaboration can it be ensured that those contemporary dynamics are present and meaningful. 相似文献
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