情报检索语言的发展方向问题--分类主题一体化新论   总被引：3，自引：0，他引：3  

何灵巧  陆宗城 《图书情报知识》2005,(1):68-72

对国内外五种著名分类主题一体化词表作了剖析，从新的视角揭示了一体化词表的实质，并根据情报检索语言的发展现状，阐明了分类主题一体化的前景，从而看清情报检索语言的发展方向。  相似文献   

国外网络分类法的发展及对我国网络分类法理论与实践的启示   总被引：5，自引：0，他引：5  

张忠秋 《新世纪图书馆》2005,(6):16-20

论文在分析网络分类法与传统文献分类法差异的基础上，阐述了国外网络分类法的特点、问题、发展趋势以及对我国网络分类法理论与实践的几点启示。  相似文献   

基于粗糙集加权的文本分类方法研究   总被引：6，自引：0，他引：6  

胡清华  谢宗霞  于达仁 《情报学报》2005,24(1):59-63

文本自动分类是当前智能信息处理中一类重要的研究课题。本文分析了基于统计理论的文本分类的基本特点,提出采用可变精度粗糙集模型中的分类质量构造新的特征词权重计算公式。这种新的加权方法,相对于广泛使用的逆文本频率加权方法,大大改进了文本样本在整个空间中的分布,使得类内距离减少,类间距离增大,在理论上将提高样本的可分性。最后利用支持向量机和K近邻两种分类器,验证了这种新的加权方法对分类效果确实有所提高。  相似文献   

简评三段式分类索刊号——与施振宏、王觊商稚兼谈刊次号设计     

孙月梅  邓永富 《图书馆建设》2005,(6):61-62,94

针对三段式分类索刊号的编号方法及在实际应用中存在的不足提出商讨意见，并对刊次号的设计提出看法。  相似文献   

Analysis of Statistical Question Classification for Fact-Based Questions   总被引：1，自引：0，他引：1  

Donald Metzler  W. Bruce Croft 《Information Retrieval》2005,8(3):481-504

Question classification systems play an important role in question answering systems and can be used in a wide range of other domains. The goal of question classification is to accurately assign labels to questions based on expected answer type. Most approaches in the past have relied on matching questions against hand-crafted rules. However, rules require laborious effort to create and often suffer from being too specific. Statistical question classification methods overcome these issues by employing machine learning techniques. We empirically show that a statistical approach is robust and achieves good performance on three diverse data sets with little or no hand tuning. Furthermore, we examine the role different syntactic and semantic features have on performance. We find that semantic features tend to increase performance more than purely syntactic features. Finally, we analyze common causes of misclassification error and provide insight into ways they may be overcome.  相似文献   

政府网站信息资源知识元模型与可视化表征研究     

王萍  王美月  王益成  黄新平 《图书情报工作》2018,62(23):14-21

[目的/意义]利用知识元模型理论研究政府网站知识服务效果的优化路径,辅以可视化表征技术,以降低大数据环境下政务用户信息获取的操作负载和知识加工的认知负荷。[方法/过程]依据相关知识元模型研究推理出符合政府网站信息资源属性特征的六元组知识元表示方法和四元组知识元本体结构,采用TextRank与HDP算法分别抽取政府网站信息资源关键词和主题词,并由领域专家根据抽取结果确定知识元,构建包含知识元本体库生成和可视化知识服务的政府网站信息资源领域知识元可视化表征模型。[结果/结论]通过政府网站发布的共享单车实例检验知识元可视化表征模型的有效性和可行性,为实现政府网站粗粒度信息服务转向以知识元为单位的细粒度知识服务范式开辟了新的研究思路,可视化知识服务模式增强了政务信息导航的结构化和用户解读领域文本语义的效果。  相似文献   

Granularity of algorithmically constructed publication-level classifications of research publications: Identification of topics     

Peter Sjögårde  Per Ahlgren 《Journal of Informetrics》2018,12(1):133-152

The purpose of this study is to find a theoretically grounded, practically applicable and useful granularity level of an algorithmically constructed publication-level classification of research publications (ACPLC). The level addressed is the level of research topics. The methodology we propose uses synthesis papers and their reference articles to construct a baseline classification. A dataset of about 31 million publications, and their mutual citations relations, is used to obtain several ACPLCs of different granularity. Each ACPLC is compared to the baseline classification and the best performing ACPLC is identified. The results of two case studies show that the topics of the cases are closely associated with different classes of the identified ACPLC, and that these classes tend to treat only one topic. Further, the class size variation is moderate, and only a small proportion of the publications belong to very small classes. For these reasons, we conclude that the proposed methodology is suitable to determine the topic granularity level of an ACPLC and that the ACPLC identified by this methodology is useful for bibliometric analyses.  相似文献   

Four pitfalls in normalizing citation indicators: An investigation of ESI’s selection of highly cited papers     

Zhigang Hu  Wencan Tian  Shenmeng Xu  Chunbo Zhang  Xianwen Wang 《Journal of Informetrics》2018,12(4):1133-1145

InCites Essential Science Indicators is becoming increasingly used to identify top-performing research and evaluate the impact of institutes. Unfortunately, our study shows that ESI indicators, as well as other normalized citation indicators, have the following flaws. First, the publication month and the online-to-print delay affect a paper’s probability of becoming a Highly Cited Paper (HCP). Papers published in the earlier months of the year are more likely to accumulate enough citation counts to rank at the top 1% compared with those published in later months of the year. Papers with longer online-to-print delays have an apparent advantage for being selected as HCPs. Research field normalizations lead to the third pitfall. Different research fields have different citation thresholds for HCPs, making research field classification important for a journal. In addition, the uniform thresholds for both articles and reviews in ESI affect the reliability of HCP selection because, on average, reviews tend to have higher citation rates than articles. ESI’s selection of HCPs provides an intuitive feel for the problems of normalized citation impact indicators, such as those provided in InCites and SciVal.  相似文献   

数字调制类型的识别及实现     

宋全有  李万高 《商丘职业技术学院学报》2006,5(2):59-61

通信信号的调制识别是目前研究的热点问题.本文给出一种新的数字调制信号识别方法.高速数字专用芯片ADSP2101是此方法具体实现的重要器件,这一方法在实际通信中有着广泛的应用.  相似文献   

辽宁西部地区先秦时期聚落遗址空间格局分析     

公雪霜  于丽君  聂跃平  朱建峰  潘玉青 《中国科学院大学学报》2016,33(3):373-379

聚落考古是以聚落遗址为研究对象的考古学重要手段之一.选取遗址数目众多的辽宁西部地区,采用决策树分类和基于遗址等级权重的改进聚类分析方法划分聚落,研究聚落分布及其内部结构关系.经分析,辽宁西部地区聚落分布受到水系、地貌和气候的共同作用,不同时期呈现出不同形态.区域中最大的聚落位于大凌河支流流域,该位置与史料中记载的辽西区域郡首阳乐的位置十分相近.通过对遗址等级的统计分析,各聚落内高等级遗址所占比例逐渐减小,最后趋于5%左右,各聚落高等级遗址的控制范围与位置和聚落内部遗址数目关系密切.  相似文献