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通过对网上3个免费专利数据库的收录范围、检索技巧等方面的介绍和分析,提出检索时应注意的问题,为用户使用专利文献提供参考。 相似文献
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Google Scholar是一种重要的检索工具。作者从应用角度中抽样统计并分析了这种工具的一些不足,包括对谷歌学术的自动检索式扩展,专利检索,引用功能3个方面,在统计结果分析中可能对用户产生误导的地方。 相似文献
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《Information processing & management》2004,40(5):829-847
In this paper we present an Information Retrieval System (IRS) which is able to work with structured document collections. The model is based on the influence diagrams formalism: a generalization of Bayesian Networks that provides a visual representation of a decision problem. These offer an intuitive way to identify and display the essential elements of the domain (the structured document components and their usefulness) and also how these are related to each other. They have also associated quantitative knowledge that measures the strength of the interactions. By means of this approach, we shall present structured retrieval as a decision-making problem. Two different models have been designed: SID (Simple Influence Diagram) and CID (Context-based Influence Diagram). The main difference between these two models is that the latter also takes into account influences provided by the context in which each structural component is located. 相似文献
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数字信息具有复杂的生命过程。典型的信息生命周期包括发现、采集、试用、选择、订购、提供检索、管理与维护、更新或终止八个阶段,数字资源管理系统在信息生命周期的每个阶段发挥着应有的作用。在现有基础上,数字资源管理系统应向标准化、规范化、XML规则、馆间链接、集成化、特色化、智能化的方向发展。 相似文献
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帮助或协助主要动词构成谓语动词词组的词被称为助动词。助动词经常放在形容词或动词的前面,用来表示愿望、可能、应该、必须等,它属于动词的一种。本文就基于语料库检索的方法来分析研究W1ll和Shall的应用变化,也借此为英语教学提供一些可供参考的建议。 相似文献
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Through the recent NTCIR workshops, patent retrieval casts many challenging issues to information retrieval community. Unlike newspaper articles, patent documents are very long and well structured. These characteristics raise the necessity to reassess existing retrieval techniques that have been mainly developed for structure-less and short documents such as newspapers. This study investigates cluster-based retrieval in the context of invalidity search task of patent retrieval. Cluster-based retrieval assumes that clusters would provide additional evidence to match user’s information need. Thus far, cluster-based retrieval approaches have relied on automatically-created clusters. Fortunately, all patents have manually-assigned cluster information, international patent classification codes. International patent classification is a standard taxonomy for classifying patents, and has currently about 69,000 nodes which are organized into a five-level hierarchical system. Thus, patent documents could provide the best test bed to develop and evaluate cluster-based retrieval techniques. Experiments using the NTCIR-4 patent collection showed that the cluster-based language model could be helpful to improving the cluster-less baseline language model. 相似文献
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当前国内大学英语转型过程中,许多从事ESP研究的专家和学者主张在ESP教材编写过程中应考虑到教师因素,即根据教师情况进行适当调整。本文尝试分析这种观点的理论基础,其在实际教学中存在的弊病,提出教师应当学习专业英语知识,通过学习适应教材,而不是教材来适应教师。 相似文献
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How to merge and organise query results retrieved from different resources is one of the key issues in distributed information retrieval. Some previous research and experiments suggest that cluster-based document browsing is more effective than a single merged list. Cluster-based retrieval results presentation is based on the cluster hypothesis, which states that documents that cluster together have a similar relevance to a given query. However, while this hypothesis has been demonstrated to hold in classical information retrieval environments, it has never been fully tested in heterogeneous distributed information retrieval environments. Heterogeneous document representations, the presence of document duplicates, and disparate qualities of retrieval results, are major features of an heterogeneous distributed information retrieval environment that might disrupt the effectiveness of the cluster hypothesis. In this paper we report on an experimental investigation into the validity and effectiveness of the cluster hypothesis in highly heterogeneous distributed information retrieval environments. The results show that although clustering is affected by different retrieval results representations and quality, the cluster hypothesis still holds and that generating hierarchical clusters in highly heterogeneous distributed information retrieval environments is still a very effective way of presenting retrieval results to users. 相似文献
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网络信息检索研究综述 总被引：7，自引：0，他引：7
本文对1995～2002年问发表的有关网络信息检索的40篇优秀论文，从检索工具、检索技巧和发展趋势等几个方面进行了分析和评价，展示了我国学者对网络信息检索方面研究的现状和成果，表明我国在网络检索研究上已经达到了一定水平。 相似文献
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M.T. Martín-Valdivia M.C. Díaz-GalianoA. Montejo-Raez L.A. Ureña-López 《Information processing & management》2008
Nowadays, access to information requires managing multimedia databases effectively, and so, multi-modal retrieval techniques (particularly images retrieval) have become an active research direction. In the past few years, a lot of content-based image retrieval (CBIR) systems have been developed. However, despite the progress achieved in the CBIR, the retrieval accuracy of current systems is still limited and often worse than only textual information retrieval systems. In this paper, we propose to combine content-based and text-based approaches to multi-modal retrieval in order to achieve better results and overcome the lacks of these techniques when they are taken separately. For this purpose, we use a medical collection that includes both images and non-structured text. We retrieve images from a CBIR system and textual information through a traditional information retrieval system. Then, we combine the results obtained from both systems in order to improve the final performance. Furthermore, we use the information gain (IG) measure to reduce and improve the textual information included in multi-modal information retrieval systems. We have carried out several experiments that combine this reduction technique with a visual and textual information merger. The results obtained are highly promising and show the profit obtained when textual information is managed to improve conventional multi-modal systems. 相似文献
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城市规划不仅关系城市的合理布局和长远发展,更关系到城市居民的住宅权益的保护.城市规划和公民住房保障有着密切的关系.城市规划制度的设计,要充分体现对人居环境和住房保障的关注.住房选址规划尤其是保障性住房的规划,必须把满足和保证公民居住需求放在首位.城市拆迁、城中村改造等未来城市发展所涉及到的城市规划的修改,应该兼顾好公共利益和公民的住宅权益. 相似文献
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《Information processing & management》2022,59(5):103026
Pseudo-relevance feedback (PRF) is a classical technique to improve search engine retrieval effectiveness, by closing the vocabulary gap between users’ query formulations and the relevant documents. While PRF is typically applied on the same target corpus as the final retrieval, in the past, external expansion techniques have sometimes been applied to obtain a high-quality pseudo-relevant feedback set using the external corpus. However, such external expansion approaches have only been studied for sparse (BoW) retrieval methods, and its effectiveness for recent dense retrieval methods remains under-investigated. Indeed, dense retrieval approaches such as ANCE and ColBERT, which conduct similarity search based on encoded contextualised query and document embeddings, are of increasing importance. Moreover, pseudo-relevance feedback mechanisms have been proposed to further enhance dense retrieval effectiveness. In particular, in this work, we examine the application of dense external expansion to improve zero-shot retrieval effectiveness, i.e. evaluation on corpora without further training. Zero-shot retrieval experiments with six datasets, including two TREC datasets and four BEIR datasets, when applying the MSMARCO passage collection as external corpus, indicate that obtaining external feedback documents using ColBERT can significantly improve NDCG@10 for the sparse retrieval (by upto 28%) and the dense retrieval (by upto 12%). In addition, using ANCE on the external corpus brings upto 30% NDCG@10 improvements for the sparse retrieval and upto 29% for the dense retrieval. 相似文献
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党的十八大报告中指出要加快建设现代化武装警察力量,这是对新形势下武警部队发展建设的全新要求。在校国防生是加快建设现代化武装警察力量,推动武警部队建设科学发展的后备力量和生力军,更应该充分认识建设现代化武警的重大意义,以党的十八大精神为指导,增强献身武警部队发展建设的责任感和使命感,坚定扎根警营的理想信念,练就过硬的军事素质,具备雄厚的文化知识,为将来更好地履行责任使命,建设现代化武警,推动武警部队建设科学发展贡献青春和智慧。 相似文献
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相关概念的关联参照检索是概念检索的重要研究内容。本文提出了一种基于主题的语义关联的参照检索模型，通过融合语义网、本体论的相关知识及信息提取等语言处理技术，提取关于特定主题的文档的主题概念及概念之间的关联构成该主题的语义关联模型，并辅助于参照检索过程。 相似文献
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人类进入信息时代尤其是进入大数据时代后,信息数量急剧增长,传统信息检索方式由于其自身不足已经满足不了人们的要求。在用户体验为中心的时代,本文通过对比传统信息检索和可视化信息检索的概念、模型,提出了基于用户体验的可视化信息检索的概念、模型和检索界面,对于提高检索效率和准确性有一定的帮助。 相似文献
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J O'Connor 《Journal of the American Society for Information Science》1980,31(4):227-239
Passage retrieval (already operational for lawyers) has advantages in output form over reference retrieval and is economically feasible. Previous experiments in passage retrieval for scientists have demonstrated recall and false retrieval rates as good or better than those of present reference retrieval services. The present experiment involved a greater variety of forms of retrieval question. In addition, search words were selected independently by two different people for each retrieval question. The search words selected, in combination with the computer procedures used for passage retrieval, produced average recall ratios of 72 and 67%, respectively, for the two selectors. The false retrieval rates were (except for one predictably difficult question) respectively 13 and 10 falsely retrieved sentences per answer-paper retrieved. 相似文献
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The term mismatch problem in information retrieval is a critical problem, and several techniques have been developed, such as query expansion, cluster-based retrieval and dimensionality reduction to resolve this issue. Of these techniques, this paper performs an empirical study on query expansion and cluster-based retrieval. We examine the effect of using parsimony in query expansion and the effect of clustering algorithms in cluster-based retrieval. In addition, query expansion and cluster-based retrieval are compared, and their combinations are evaluated in terms of retrieval performance by performing experimentations on seven test collections of NTCIR and TREC. 相似文献