一个基于运动的视频检索系统

给出了一种基于运动在空间 时间域上体现的运动特征的设计方案 ,主要涉及两个模块 ,即 :运动检测模块 (Detec tionModule)和任何检索系统都必需的匹配模块 (MatchingModule)。初步试验表明 ,检测的结果基本和我们的直觉相符合。     

模糊分类与模糊匹配相结合的模糊检索

1.问题的提出文献信息检索的过程,可以看成是一个用户“查询”和文献库之间“匹配”的过程。但是,当文献库中文献数量达到几百万甚至更多时,如果仍用用户的“查询”去逐一匹配文献库,将花费很长的时间,甚至使检索方法无法付诸实用。因此,将文献适当地分成若干子类,在子类中进行检索,能缩小检索范围,可加速匹配     

一个智能化的图像检索系统IIRS

本文深入研究了支持语义查询的大型图像数据库检索技术,提出了一种新的基于内容的图像检索系统：IIRS(Intelligent Irnage Retrieval System)。该系统支持多种特征的组合查询,引入了反馈机制及语义查询,具有自动学习及再学习的能力。实验结果表明,引入相关反馈及语义查询,可大大提高检索性能,     

在预编译程序中数据库的模糊检索方法和技巧

本文介绍了VAX Rdb/VMS数据库的模糊检索方法和使用时的一些技巧,以及在预编译程序中比较串的描述方式。     

基于内容的图象检索系统的设计与实现

依据当前对图象查询的要求,本文设计了一套完整的基于内容的图象信息检索系统,该系统较以往的各种系统,功能更加全面。对基于内容的图象信息检索算法作了研究．重点阐述了对颜色、边缘、纹理等全局特征的提取与匹配算法。实验结果表明,该系统能有效、快速地检索大规模的图象数据库,具有一定的应用价值。     

基于内容的图像检索系统

分别介绍了颜色特征的描述方法和相似度匹配算法,并分析了基于颜色的图像检索的局限性,给出了相应的解决办法。     

一个图像数据库检索系统的结构设计和快速检索方法

本文介绍了图像数据库区别于常规数据库的特点,并以数字化图书馆的数据库子系统Basestar为例,介绍了图像数据库检索系统的结构和检索方法。Basestar采用综合了颜色、形状、纹理三种特征矢量的综合性检索方法,本文详细介绍了这种方法,并论述了在此方法基础上,根据三角形不等式准则改进而成的检索方法的原理和实现。实验证明Basestar 系统具有较好的检索效果,检索结果证明快速检索方法是有效的。     

A database of groups of prime-power order

The design, implementation and performance of TwoGroups, a deductive database for the 58,761 groups of order 2ⁿ, (n ≤ 8), is described. The system is implemented in NU-Prolog, a Prolog system with built-in functions for creating and using deductive databases. TwoGroups has a set-theoretic query language, which provides users with a familiar notation to access the data. The paper describes the data and its representation, the set-theoretic query language, its translator and optimiser, and the experiments on the performance of the database.     

Fuzzy relational algebra for possibility-distribution-fuzzy-relational model of fuzzy data

In the real world, there exist a lot of fuzzy data which cannot or need not be precisely defined. We distinguish two types of fuzziness: one in an attribute value itself and the other in an association of them. For such fuzzy data, we propose a possibility-distribution-fuzzy-relational model, in which fuzzy data are represented by fuzzy relations whose grades of membership and attribute values are possibility distributions. In this model, the former fuzziness is represented by a possibility distribution and the latter by a grade of membership. Relational algebra for the ordinary relational database as defined by Codd includes the traditional set operations and the special relational operations. These operations are classified into the primitive operations, namely, union, difference, extended Cartesian product, selection and projection, and the additional operations, namely, intersection, join, and division. We define the relational algebra for the possibility-distribution-fuzzy-relational model of fuzzy databases.     

基于Xcluster的XML松弛查询小枝评分方法

在Web上精确检索XML代价非常昂贵。为了缩短操作代价,定义了XML查询松弛的概念,利用三个松弛原操作对用户提交的查询进行松弛,产生查询松弛集。为了定量衡量松弛的可信度,定义了松弛损率,引入传统信息检索中TFIDF评分思想,给出了基于文档统计特性和松弛损失的XML Web检索的TFIDF评分公式,并实现该算法。一系列实验表明此方法在XML Web数据检索中具有常数查全率和较高的查准率。     

基于完全化语义的关键词检索研究*

已有方法解决了结果集要求是关于关键词检索结果全集而带来的无检索结果的问题,但非空子集作为结果集有较大冗余。提出了一种基于完全化语义的关键词检索方法,对检索关键词进行语义标准化处理,识别处理后采用不同的检索评分器评分,基于检索核给出了针对不同类型的检索算法,生成连接元组集,取得相邻拓展连接元组集,转换得到SQL检索语句,将所有的查询结果返回给用户。实验表明,采用了检索核的方法可以很好地避免数据冗余情况。     

DBORank:对象级别的关系数据库信息检索方法

对象级别的信息检索已经引起越来越多的关注和研究。针对这一研究问题,设计并实现了一个对象级别的关系数据库信息检索方法DBORank,来有效提高关系数据库信息检索效果。DBORank方法从数据库和信息检索两个角度出发,设计了一种灵活有效的评分机制,它既考虑了对象级别数据图的链接结构,又考虑了图中对象结点的内部结构,边的类型和权值,对象内容相关性等因素,同时优化了对象评分的迭代算法。实验表明DBORank方法具有良好的检索效果和效率。     

对数据库上关键词检索的研究与分析

随着网络的快速发展,数据库的使用大幅度增加。当前,数据信息基本上都是存储在关系数据库中的,使得我们目前的检索需要通过数据库交互进行。而基于文件的关键字检索技术根本无法适用于更广泛的检索。我们迫切的需要研究一种技术,该技术必须是用户友好的,高效而准确,使得用户可以在不了解SQL语句,不了解数据库模型结构的情况下,仍旧可以像传统基于文件的关键字检索一样仅仅输入关键字就可以检索到满意的结果。本文就是主要研究和分析数据库上的关键词检索。     

Using a relational database for scalable XML search

XML is a flexible and powerful tool that enables information and security sharing in heterogeneous environments. Scalable technologies are needed to effectively manage the growing volumes of XML data. A wide variety of methods exist for storing and searching XML data; the two most common techniques are conventional tree-based and relational approaches. Tree-based approaches represent XML as a tree and use indexes and path join algorithms to process queries. In contrast, the relational approach utilizes the power of a mature relational database to store and search XML. This method relationally maps XML queries to SQL and reconstructs the XML from the database results. To date, the limited acceptance of the relational approach to XML processing is due to the need to redesign the relational schema each time a new XML hierarchy is defined. We, in contrast, describe a relational approach that is fixed schema eliminating the need for schema redesign at the expense of potentially longer runtimes. We show, however, that these potentially longer runtimes are still significantly shorter than those of the tree approach. We use a popular XML benchmark to compare the scalability of both approaches. We generated large collections of heterogeneous XML documents ranging in size from 500 MB to 8 GB using the XBench benchmark. The scalability of each method was measured by running XML queries that cover a wide range of XML search features on each collection. We measure the scalability of each method over different query features as the collection size increases. In addition, we examine the performance of each method as the result size and the number of predicates increase. Our results show that our relational approach provides a scalable approach to XML retrieval by leveraging existing relational database optimizations. Furthermore, we show that the relational approach typically outperforms the tree-based approach while scaling consistently over all collections studied.

用于高效检索的数据结构模式快速匹配仿真

为了解决空间技术不断发展造成的大量空间数据难以及时处理的缺陷,提出用于数据检索的数据结构模式快速匹配方法。将网络划分多个不同的区域,每个区域分配一个域首,负责采集区域的信息,将采集的所有信息发送至中心管理系统,获取不同层次的匹配内容。通过匹配内容,获取各个匹配方式的相似度函数,通过相似度计算结果完成数据结构模式快速匹配。实验结果表明,所提方法能够有效减少通信降低,提高匹配速度,增加匹配精度,达到理想的匹配效果。     

一种基于颜色特征的图象检索方法

提出了一种改进的基于颜色感知特征和图象检索方法。这种方法采用符合人类视觉特征的ＨＳＶ颜色空间来表示图象的颜色特性,利用人对颜色的感知来对颜色分量进行等间隔的量化工形成特征矢量,用直方图交叉算法进行图象的匹配。用户可以通过示例方式,指定颜色或指定区域来表示查询的视觉要求。