网上外文科技期刊最新论文题录保障系统的研制

介绍网上外文科技期刊最新论文题录保障系统的研制目标、总体结构及主要功能,着重阐述系统自动下载和自动标 引的实现方法。     

关于自然语言检索问题

自然语言检索当前仅在关键词检索的层次上已经实现，重点分析了全文检索所适应和不适应的检索要求及其评价，用分析说明了当前关于自然语言检索的主流观点的不切实际，指出自然语言检索的发展方向是与情报检索语言结合和融合。     

特殊合订图书的标引与著录

针对特殊合订图书的特点，文章对特殊合订图书的分类标引、主题标引和CN—MARC著录方法分别进行了探讨。     

探析自动索引原理

文章试图对自动索引的方法作一些探讨。首先介绍了自动索引的五种理论模型和六种自动标引方法，随后探讨了自动索引中不可或缺的两个对象——全文索引和数据库索引的原理。     

基于用户自然标注的TF-IDF辅助标引算法及实证研究

[目的/意义] 从用户角度出发,研究基于用户自然标注的TF-IDF辅助标引算法。[方法/过程] 首先以核心期刊论文中作者标注的关键词和分类号为源数据,通过对关键词词频进行统计,使用TF-IDF算法构建用户标注词表、形成标引知识库,然后通过IK Analyzer分词软件对待标引的科技项目数据进行切词和停用词处理,进而使用TF-IDF算法和位置加权算法提取科技项目数据的特征词,最终实现对科技项目数据进行关键词和分类的同步标引。[结果/结论] 实验结果表明,机标关键词与人标关键词的相似比在60%以上的科技项目数据占总数的68.1%,机标分类号与人标分类号前三位一致的占总数的83.9%,结果表明基于用户自然标注数据并采用TF-IDF算法在关键词和分类标引方面是可行的。     

Dimensions: A competitor to Scopus and the Web of Science?

Dimensions is a partly free scholarly database launched by Digital Science in January 2018. Dimensions includes journal articles and citation counts, making it a potential new source of impact data. This article explores the value of Dimensions from an impact assessment perspective with an examination of Food Science research 2008–2018 and a random sample of 10,000 Scopus articles from 2012. The results include high correlations between citation counts from Scopus and Dimensions (0.96 by narrow field in 2012) as well as similar average counts. Almost all Scopus articles with DOIs were found in Dimensions (97% in 2012). Thus, the scholarly database component of Dimensions seems to be a plausible alternative to Scopus and the Web of Science for general citation analyses and for citation data in support of some types of research evaluations.     

一种凸轮升程误差的非接触式测量新方法

分析现有几种凸轮升程误差测量方法的优、缺点后，提出一种基于图像处理的凸轮升程误差的非接触式测量新方法．理论分析和比较实验结果表明，该测量方法简便易行，测量精度较高，具有一定的应用价值．     

数据检索中索引技术的探讨

设计索引的目的是为了加快数据检索．文章就与索引相关的一些特征元素．提出了创建索引中数据目录项的3种不同方法．同时对B^ 索引进行了描述．分析了其在进行数据搜索的实现原理．简要个绍了在实现数据删除和插入时的优化思路．     

Automatic indexing of online health resources for a French quality controlled gateway

The profusion of online resources calls for tools and methods to help Internet users find precisely what they are looking for. Quality controlled gateway CISMeF provides such services for health resources. However, the human cost of maintaining and updating the catalogue are increasingly high. This paper presents the automatic indexing system currently developed in the CISMeF team to be used as such for preliminary indexing, or after human reviewing for the final indexing. The system architecture, using the INTEX platform for MeSH term extraction is detailed. The results of a first evaluation tend to indicate that the automatic indexing strategy is relevant, as it achieves a precision comparable to that of other existing operational systems. Moreover, the system presented in this paper retrieves keyword/qualifier pairs as opposed to single terms, therefore providing a significantly more precise indexing. Further development and tests will be carried out in order to improve the coverage of the dictionaries, and validate the efficiency of the system in the indexers’ everyday work.     

移动从动件盘形凸轮压力角的分析

通过对移动从动件凸轮轮廓曲线的几何分析,运用三心定理得出凸轮压力角的计算公式,用Excel准确计算出凸轮轮廓曲线上各点的压力角后运用图表分析不同运动规律、不同升程及不同偏心距的情况下凸轮轮廓曲线上各点压力角的变化规律。