CA光盘版检索方法与技巧

Chemical Abstracts (CA) is widely used all over the world. In this article, the methods and skills of retrieving CA on CD are studied. Methods of combining CA on CD retrieval with Dialog online retrieval are also described.     

中刊库检索效率及其影响因素比较分析

Based on the retrieval function of the Chinese Journal Database and the China Journal Net Bibliography and Abstract Database, the article analyzes the retrieval results of the two databases and their influence factors for the same retrieval missions. The article also discusses how to construct and evaluate a database.     

论自然语言检索

With its advantages in information retrieval, such as simple in indexing and convenient in information re-trieval, natural language is now widely used in idonnafion retrieval and network retrieval. However, due to some charac-teristics of the natural language itself, its retrieval result is usually tmsafisfactory. This paper sumamrizes several main fac-tots that restrict natural language retrieval and introduces a concept space method to improve its retrieval efficiency.     

多约束条件下检索组合模型的应用

With an analysis of the main document databases, this paper discusses the combined retrieval models used under the multi-restrictive conditions by use of the conditional probability theory. The paper provides system programmers with combined probability theory and its application examples. It's useful for users to increase recall ratio, pertinency ratio and search rate.     

基于内容的智能网络多媒体信息过滤检索

The paper discusses the construction of a content-based intelligent system that performs multimedia information filtering and retrieving on the Internet. The system disassembles the multimedia information into different media objects and describes them with vectors for content-based retrieval. In the user study module, the system uses the BP neural network to clarify the user interests for intelligent filtering and retrieving.     

IA应用研究--我国政府网站考察与评价

Issuing government information is a major task of the government Website. So it‘‘s important that the government Website is organized in accordance with the users‘‘ need and habit. In this article, the theory of Information Architecture (IA) is used to examine and evaluate some government Websites in an attempt to investigate some elements of government Websites such as the navigation system, information retrieval method and ways of information organizing and labeling.     

网络信息检索技术的智能化趋势

Beginning with an analysis of the present situation of network information retrieval techniques, this article points out the main problems existent therein. It also probes into the prospects of applying the theory and technique of artificial intelligence to network information retrieval techniques as well as its intelligence trend.     

检索语言在文献检索教学中的定位

Focused on the use of retrieval language in document retrieval teaching, this article discusses the influence of retrieval language on retrieval tool, retrieval mode and retrieval efficiency. It suggests that a retrieval language system be constructed and points out its proportion to document retrieval teaching.     

Web数据库技术综述

Web-Database is the base of many network applications such as Web information retrieval system, Web information publishing and Electronic Commerce. This article focuses on several popular Web-Database technologies such as CGI, ISAPI, IDC, ASP and Java Applet, analyzing and comparing their structure, characteristics, advantages and disadvantages. Finally, it discusses the main structure of the Web-Database technology.     

万维网上的全文检索技术及其发展

The conception and characteristics of full text retrieval are expounded. The basic structure and key technologies of a full text retrieval system on WWW are put forward. According to the development direction of intelligent information retrieval, the author discusses three approaches of combining artificial intelligence with information retrieval.     

Color image retrieval technique based on color features and image bitmap

The field of color image retrieval has been an important research area for several decades. For the purpose of effectively retrieving more similar images from the digital image databases, this paper uses the color distributions, the mean value and the standard deviation, to represent the global characteristics of the image. Moreover, the image bitmap is used to represent the local characteristics of the image for increasing the accuracy of the retrieval system. As the experimental results indicated, the proposed technique indeed outperforms other schemes in terms of retrieval accuracy and category retrieval ability. Furthermore, the total memory space for saving the image features of the proposed method is less than Chan and Liu’s method.     

基于内容的图像检索

本文首先简要地描述了可供于检索的一些图片特征,然后介绍了目前比较成熟的基于纹理、颜色、形状的图像检索,最后引入HSNN神经网络来实现基于语义的图像检索,提出了一种解决该问题的思路。     

基于颜色内容的图像检索原理与方法

本文介绍了基于颜色内容的图象检索技术原理,分析了颜色的特征、颜色直方图构造、颜色直方图匹配算法及其优化、索引编制和检索匹配的过程等问题。     

基于广义平均直方图的图像检索方法

由于传统直方图方法不能描述图像中相邻像素之间的相关性和颜色在图像内的空间分布特征,文中引入"广义图像"的概念,即把原图像与平滑图像相对应的两个像素组合起来,形成的一个二元组.提出了广义平均直方图的概念,首先将颜色量化方法扩展到广义图像中,把广义图像的颜色量化为143维.然后计算每一维对应的聚类中心和组合数,最后计算每一维对应的频数,得出广义平均直方图.为了提高对多色彩图像的检索效率,把自动参考颜色表方法引入图像匹配中.实验结果表明,基于广义平均直方图的图像检索方法的有效性好、准确性高.     

基于内容的图像信息检索综述

基于内容的图像检索技术，即从大量的静止或活动视频图像库中检索包含目标物体的图像（或视频片段），在高度信息化的今天，已成为内容图像库中图像信息组织和管理不可缺少的技术，本文介绍了基于内容检索技术的进展，并对其主要方法如基于颜色、形状、纹理等静止图像检索技术以及视频检索技术进行了讨论。     

XMage: An image retrieval method based on partial similarity

XMage is introduced in this paper as a method for partial similarity searching in image databases. Region-based image retrieval is a method of retrieving partially similar images. It has been proposed as a way to accurately process queries in an image database. In region-based image retrieval, region matching is indispensable for computing the partial similarity between two images because the query processing is based upon regions instead of the entire image. A naive method of region matching is a sequential comparison between regions, which causes severe overhead and deteriorates the performance of query processing. In this paper, a new image contents representation, called Condensed eXtended Histogram (CXHistogram), is presented in conjunction with a well-defined distance function CXSim() on the CX-Histogram. The CXSim() is a new image-to-image similarity measure to compute the partial similarity between two images. It achieves the effect of comparing regions of two images by simply comparing the two images. The CXSim() reduces query space by pruning irrelevant images, and it is used as a filtering function before sequential scanning. Extensive experiments were performed on real image data to evaluate XMage. It provides a significant pruning of irrelevant images with no false dismissals. As a consequence, it achieves up to 5.9-fold speed-up in search over the R*-tree search followed by sequential scanning.     

A Query Expansion Framework in Image Retrieval Domain Based on Local and Global Analysis

We present an image retrieval framework based on automatic query expansion in a concept feature space by generalizing the vector space model of information retrieval. In this framework, images are represented by vectors of weighted concepts similar to the keyword-based representation used in text retrieval. To generate the concept vocabularies, a statistical model is built by utilizing Support Vector Machine (SVM)-based classification techniques. The images are represented as "bag of concepts" that comprise perceptually and/or semantically distinguishable color and texture patches from local image regions in a multi-dimensional feature space. To explore the correlation between the concepts and overcome the assumption of feature independence in this model, we propose query expansion techniques in the image domain from a new perspective based on both local and global analysis. For the local analysis, the correlations between the concepts based on the co-occurrence pattern, and the metrical constraints based on the neighborhood proximity between the concepts in encoded images, are analyzed by considering local feedback information. We also analyze the concept similarities in the collection as a whole in the form of a similarity thesaurus and propose an efficient query expansion based on the global analysis. The experimental results on a photographic collection of natural scenes and a biomedical database of different imaging modalities demonstrate the effectiveness of the proposed framework in terms of precision and recall.     

Dynamic two-stage image retrieval from large multimedia databases

Content-based image retrieval (CBIR) with global features is notoriously noisy, especially for image queries with low percentages of relevant images in a collection. Moreover, CBIR typically ranks the whole collection, which is inefficient for large databases. We experiment with a method for image retrieval from multimedia databases, which improves both the effectiveness and efficiency of traditional CBIR by exploring secondary media. We perform retrieval in a two-stage fashion: first rank by a secondary medium, and then perform CBIR only on the top-K items. Thus, effectiveness is improved by performing CBIR on a ‘better’ subset. Using a relatively ‘cheap’ first stage, efficiency is also improved via the fewer CBIR operations performed. Our main novelty is that K is dynamic, i.e. estimated per query to optimize a predefined effectiveness measure. We show that our dynamic two-stage method can be significantly more effective and robust than similar setups with static thresholds previously proposed. In additional experiments using local feature derivatives in the visual stage instead of global, such as the emerging visual codebook approach, we find that two-stage does not work very well. We attribute the weaker performance of the visual codebook to the enhanced visual diversity produced by the textual stage which diminishes codebook’s advantage over global features. Furthermore, we compare dynamic two-stage retrieval to traditional score-based fusion of results retrieved visually and textually. We find that fusion is also significantly more effective than single-medium baselines. Although, there is no clear winner between two-stage and fusion, the methods exhibit different robustness features; nevertheless, two-stage retrieval provides efficiency benefits over fusion.     

一种新的用于图像检索的颜色一空间特征

为了解决图像检索中颜色直方图无法描述颜色空间位置信息的问题,提出了一种新的基于色彩量化的凸壳内角直方图特征.针对量化后HSV颜色空间中某一具体量化颜色值对应像素点的空间分布,首先计算包含这些像素点位置信息的凸壳,并对该凸壳的所有内角建立直方图.然后处理所有量化颜色值提取整幅图像的凸壳内角直方图特征.将该方法和一些文献中提出的方法进行的比较实验结果表明:提出的新特征可以有效地描述颜色空间位置信息,在查准率和查全率指标上均优于已有文献中的一些方法.     

智能情报检索与NLP

本文论述了智能情报检索、自然语言的内涵、特点，分析了国内外智能情报检索的研究状况，针对智能情报检索系统中自然语言的标引和检索及建立未来更为便捷的智能情报检索系统提出几点建议。