中文数据库检索技术研究的一项新内容 兼谈《美国国会图书馆拼音转换计划:新汉语罗马化准则》的诞生及其主要内容     

刘静一 《情报学报》2003,22(2):155-162

文章在简单论述从威妥玛拼音产生到汉语拼音诞生的全过程基础之上,首次在国内全面阐述和分析了<美国国会图书馆拼音转换计划>的主要内容,并且详细、准确地介绍了威氏标音和汉语拼音的对照表,以及美国国会图书馆对于中国传统地名由威氏标音向汉语拼音转换的具体标目修改形式和修改时间.这对于我国中文数据库检索技术的研究和全球信息资源共享来说是相当重要的.这是西方图书馆史上的一个新的里程碑.  相似文献   

搜索引擎的商业行为分析与思考   总被引：6，自引：0，他引：6  

王秀峰  柯青 《情报科学》2005,23(7):1114-1118,1120

随着搜索引擎相互之间竞争的加剧，许多搜索引擎开始选择商业化发展路线。在本文中，分析了当前搜索引擎商业化发展出现的原因，探讨了搜索引擎商业活动的主要模式，并对未来搜索引擎商业发展中出现的问题提出初步的思考。  相似文献   

Relevance-based entity selection for ad hoc retrieval     

Faezeh Ensan  Feras Al-Obeidat 《Information processing & management》2019,56(5):1645-1666

Recent developments have shown that entity-based models that rely on information from the knowledge graph can improve document retrieval performance. However, given the non-transitive nature of relatedness between entities on the knowledge graph, the use of semantic relatedness measures can lead to topic drift. To address this issue, we propose a relevance-based model for entity selection based on pseudo-relevance feedback, which is then used to systematically expand the input query leading to improved retrieval performance. We perform our experiments on the widely used TREC Web corpora and empirically show that our proposed approach to entity selection significantly improves ad hoc document retrieval compared to strong baselines. More concretely, the contributions of this work are as follows: (1) We introduce a graphical probability model that captures dependencies between entities within the query and documents. (2) We propose an unsupervised entity selection method based on the graphical model for query entity expansion and then for ad hoc retrieval. (3) We thoroughly evaluate our method and compare it with the state-of-the-art keyword and entity based retrieval methods. We demonstrate that the proposed retrieval model shows improved performance over all the other baselines on ClueWeb09B and ClueWeb12B, two widely used Web corpora, on the [email protected], and [email protected] metrics. We also show that the proposed method is most effective on the difficult queries. In addition, We compare our proposed entity selection with a state-of-the-art entity selection technique within the context of ad hoc retrieval using a basic query expansion method and illustrate that it provides more effective retrieval for all expansion weights and different number of expansion entities.  相似文献   

垂直网站及其信息服务模式   总被引：7，自引：0，他引：7  

郝凤英 《情报理论与实践》2002,25(2):136-137

The paper introduces vertical portals and their information service modes,analyzes the inevitability of their emergence and development, and finally gives some suggestions as to how to do a good job in providing information service through vertical portals.  相似文献   

基于本体论的数字图书馆搜索引擎的研究     

赵亚莉  魏淑琴 《现代情报》2007,27(8):104-106

基于本体（ontology）理论,利用本体对概念、术语及其相互关系的规范化描述,勾画出数字图书馆领域的基本知识体系,构建了数字图书馆领域本体库;然后,对现有的图书馆搜索引擎系统进行了改进,将构建的本体库引入到系统中,实现了基于本体的信息检索,方便用户对资源的查询,为用户提供高质量的个性化服务。  相似文献   

Dictionary-based text categorization of chemical web pages     

Chun-Yan Liang  Li GuoZhao-Jie Xia  Feng-Guang NieXiao-Xia Li  Liang SuZhang-Yuan Yang 《Information processing & management》2006

A new dictionary-based text categorization approach is proposed to classify the chemical web pages efficiently. Using a chemistry dictionary, the approach can extract chemistry-related information more exactly from web pages. After automatic segmentation on the documents to find dictionary terms for document expansion, the approach adopts latent semantic indexing (LSI) to produce the final document vectors, and the relevant categories are finally assigned to the test document by using the k-NN text categorization algorithm. The effects of the characteristics of chemistry dictionary and test collection on the categorization efficiency are discussed in this paper, and a new voting method is also introduced to improve the categorization performance further based on the collection characteristics. The experimental results show that the proposed approach has the superior performance to the traditional categorization method and is applicable to the classification of chemical web pages.  相似文献   

典型的图像搜索引擎特征和评价   总被引：3，自引：0，他引：3  

汪社教 《情报科学》2003,21(4):423-424

本文首先介绍图像搜索引擎技术基础，并对图像搜索引擎进行分类；然后挑选网上较为典型的搜索引擎，分析它们的特点且给予扼要的评述。  相似文献   

浅论科技项目查新与专利查新的异同   总被引：1，自引：0，他引：1  

云洁 《情报科学》2003,21(10):1064-1065

本文通过对科技查新与专利查新的定义、程序和结果进行比较，指出两者的异同。  相似文献   

Improvement of building field association term dictionary using passage retrieval     

Uddin Md.  Elmarhomy  Elsayed  Masao  Kazuhiro  Jun-ichi 《Information processing & management》2007,43(6):1793

Field Association (FA) terms are a limited set of discriminating terms that can specify document fields. Document fields can be decided efficiently if there are many relevant FA terms in that documents. An earlier approach built FA terms dictionary using a WWW search engine, but there were irrelevant selected FA terms in that dictionary because that approach extracted FA terms from the whole documents. This paper proposes a new approach for extracting FA terms using passage (portions of a document text) technique rather than extracting them from the whole documents. This approach extracts FA terms more accurately than the earlier approach. The proposed approach is evaluated for 38,372 articles from the large tagged corpus. According to experimental results, it turns out that by using the new approach about 24% more relevant FA terms are appending to the earlier FA term dictionary and around 32% irrelevant FA terms are deleted. Moreover, precision and recall are achieved 98% and 94% respectively using the new approach.  相似文献   

搜索引擎网页快照的实现与安全     

孙静  赵恒永 《中国科技信息》2007,(11):138-139,141

文章介绍了搜索引擎网页快照系统的实现以及在安全性能方面的研究。当前的多数搜索引擎网站提供的网页快照,能够使用户更加快速和方便地访问较早时期的网页,但它们并没有对其中的网页安全进行判断。文章中的网页快照系统在实现网页快照的同时,通过建立网页脚本语言学习解释器,运用机器学习技术、词法分析技术等对网页上可能存在的不安全代码进行判断和去除,从而保证提供给用户的是尽量安全的网页快照。  相似文献