ADO控件访问数据库的各种技巧探讨

本文讲述了使用ADO控件访问数据库时如何用程序来实现数据库的连接和数据感知控件与数据库的绑定、如何实现动态查和动作查询以及如何用ADO控件的事件来限制字段取值等技巧，这些技巧在开发数据库应用程序中很有实用价值。     

基于XML的飞行仿真数据库的研究

XML以其易扩展、易移植等特点被广泛应用在信息传递过程中.工程飞行仿真教据库为飞机设计人员提供大量的可视化试验结果数据.针对飞机的不同型号和试验需求,如何实现数据库的通用性,一直是设计人员长期关注的问题.动态生成数据库模型是解决该问题的关键.本文给出了某工程飞行仿真数据库的功能和结构,并借助XML技术实现了两个数据库之间的信息传递,实现仿真数据库的动态建模,增强了该数据库的通用性.     

基于中间件技术的制造业需求管理的设计与实现

本文通过八个制造项目抽取出制造业需求管理系统模型,并且描述了如何运用中间件技术实现制造业需求管理.本文设计出系统的功能模块和数据库表结构以及表之间的关系;根据J2EE三层架构,给出了需求管理软件实现的静态技术框架和动态技术框架.     

数据库连接的动态设置与加密解密

本文介绍在.NET环境下,用C#开发MS SQL Server数据库应用软件时,通过ADO.NET方式连接数据库对连接字符串进行动态配置并进行加密、解密处理,实现ADO.NET数据库连接的动态设置.     

基于JSP/WML的WAP数据库应用的实现

WAP技术与JSP技术结合,能够开发出丰富多彩的动态WAP网站.本文论述了WAP技术体系以及如何使用JSP结合WML开发WAP数据库应用系统,并给出了一个WAP数据库应用系统的实现.     

利用ASP.NET中ADO.NET技术实现数据库的动态访问

本文介绍了ASP.NET及其新一代的数据库访问技术ADO.NET,并将其与ASP和ADO进行比较,阐述了新一代技术的特点。基于酒店客户信息管理给出了一个实例阐述如何采用ADO.NET技术实现对数据库的动态访问。     

DelPhi环境下基于ADO对象动态创建和连接加密的Access数据库

介绍了在用Delphi开发Access数据库应用程序过程中,会碰到当将应用程序安装到不同的机器上,由于数据环境改变导致数据库不能正常连接,致使程序无法运行的问题;以及如何动态的对数据库进行加密和连接等问题.结合实例详细阐述了ADO、ADOX接口的用法以及如何动态创建和连接加密的Access数据库,较好的解决了以上存在的问题.     

自动维护应用程序的数据库访问用户口令

用户口令的安全性是数据库安全的关键所在,对数据库应用程序来说,如何动态地维护用户口令显得尤为重要.本文提出自动维护数据库访问用户口令的方法,同时采用了多重口令密文算法,使数据库有了更高的安全保障.     

动态数据库的ORM实现

针对现有的ORM组件不能实现运行时动态改变数据库结构的不足,文章提出了一种动态数据库的ORM解决方案,该方案从分析设计数据库的基本原则入手,给出了一种将索引表和动态数据表相结合的ORM模型,通过索引表间接实现了动态数据库的ORM,弥补了现有ORM组件的不足.同时分析比较了动态数据库ORM和传统JDBC直连的效率.     

异构数据库的变化捕捉和动态同步策略的研究与比较

随着信息技术的发展,信息量的爆炸性的增加异构数据库间,如何进行有效的动态同步已经成为研究的热点。本文综述了异构数据库动态捕捉的常用的策略和技术,并分析了这些策略的优缺点,为研究人员如何选取自身合适的同步策略提供了基础。     

Text Database Discovery on the Web: Neural Net Based Approach

As large numbers of text databases have become available on the Web, many efforts have been made to solve the text database discovery problem: finding which text databases (out of many candidates) are most likely to provide relevant documents to a given query. In this paper, we propose a neural net based approach to this problem. First, we present a neural net agent that learns about underlying text databases from the user's relevance feedback. For a given query, the neural net agent, which is sufficiently trained on the basis of the backpropagation learning mechanism, discovers the text databases associated with the relevant documents and retrieves those documents effectively. In order to scale our approach with the large number of text databases, we also propose the hierarchical organization of neural net agents which reduces the total training cost at the acceptable level. Finally, we evaluate the performance of our approach by comparing it to those of the conventional well-known statistical approaches.     

Discovering Text Databases with Neural Nets

Since documents on the Web are naturally partitioned into many text databases, the efficient document retrieval process requires identifying the text databases that are most likely to provide relevant documents to the query and then searching for the identified text databases. In this paper, we propose a neural net based approach to such an efficient document retrieval. First, we present a neural net agent that learns about underlying text databases from the user's relevance feedback. For a given query, the neural net agent, which is sufficiently trained on the basis of the BPN learning mechanism, discovers the text databases associated with the relevant documents and retrieves those documents effectively. In order to scale our approach with the large number of text databases, we also propose the hierarchical organization of neural net agents which reduces the total training cost at the acceptable level. Finally, we evaluate the performance of our approach by comparing it to those of the conventional well-known approaches. Received 5 March 1999 / Revised 7 March 2000 / Accepted in revised form 2 November 2000     

Net-VE系统中动态共享状态管理方法的研究

本文介绍了net VE系统中动态共享状态管理的三种方法及其优缺点,分析了如何使用分布式数据库来管理net VE中的共享状态,讨论了与分布式数据库的接口设计、接口要完成的主要功能、数据库中要存储的对象类型、共享状态的更新策略等。     

Searchable words on the Web

In designing data structures for text databases, it is valuable to know how many different words are likely to be encountered in a particular collection. For example, vocabulary accumulation is central to index construction for text database systems; it is useful to be able to estimate the space requirements and performance characteristics of the main-memory data structures used for this task. However, it is not clear how many distinct words will be found in a text collection or whether new words will continue to appear after inspecting large volumes of data. We propose practical definitions of a word and investigate new word occurrences under these models in a large text collection. We inspected around two billion word occurrences in 45 GB of World Wide Web documents and found just over 9.74 million different words in 5.5 million documents; overall, 1 word in 200 was new. We observe that new words continue to occur, even in very large datasets, and that choosing stricter definitions of what constitutes a word has only limited impact on the number of new words found.     

海量文本数据库中的高效并行频繁项集挖掘方法

针对大规模文本数据库中频繁项集挖掘的特殊要求，本文提出了一种新的并行挖掘算法parFIM。parFIM以一种简单的数据结构H-Struct为基础，对数据进行纵向划分从而实现并行挖掘。算法同时考虑了去除短模式和减少重复模式。实验结果表明，parFIM能够很好地适用于大规模文本数据库中的频繁项集挖掘任务。     

基于自然语言理解的受限领域自动应答系统

提出了一种在受限领域内进行自动应答的系统总体结构，通过构建领域词汇库、领域本体库、领域真实问句语料库及领域知识文本库等领域资源库，并借助于这些领域资源来理解问句和知识文本，在一定程度上降低了理解的难度。文章以银行业务咨询服务为例，分析了系统结构及实现过程，对问句分析、答案析取、问句语料库构建、文本知识标注等功能模块的实现进行了详细介绍。     

基于脆弱性数字水印的图象完整性验证研究

计算机网络技术的飞速发展与信息媒体的数字化 ,使得在网络环境中对数字产品实施有效的内容保护成为一个迫在眉睫的现实问题 .传统的数字签名技术只是用于对通信领域的信息传送进行篡改检测 ,而脆弱性数字水印技术则为网络环境下多媒体的内容保护提供了一个有效的解决方案 .与鲁棒性水印不同的是 ,脆弱性水印主要用于检测发生在多媒体数据中的篡改 ,并对其定位 .为了推动我国在此前沿领域研究工作的进一步深入 ,这里就当前脆弱性数字图象图象水印技术的基本特征、一般原理、研究现状、攻击方法及发展方向进行一个综述 .     

一种基于HBase的空间关键字查询算法

针对传统关系数据库处理海量空间文本数据的不足,基于HBase数据库提出了一种结合Geohash编码与分词技术的空间文本索引方案,并基于该空间文本索引提出了一种多边形区域内的空间关键字查询算法。通过与传统经纬度索引方案的实验比较,验证了算法的高效性和可扩展性。     

A rule triggering system for automatic text-to-sign translation

The topic of this paper is machine translation (MT) from French text into French sign language (LSF). After arguing in favour of a rule-based method, it presents the architecture of an original MT system, built on two distinct efforts: formalising LSF production rules and triggering them with text processing. The former is made without any concern for text or translation and involves corpus analysis to link LSF form features to linguistic functions. It produces a set of production rules which may constitute a full LSF production grammar. The latter is an information extraction task from text, broken down in as many subtasks as there are rules in the grammar. After discussing this architecture, comparing it to the traditional methods and presenting the methodology for each task, the paper present the set of production rules found to govern event precedence and duration in LSF and gives a progress report on the implementation of the rule triggering system. With this proposal, it is also hoped to show how MT can benefit today from sign language processing.     

全文检索模型综述

全文检索的应用导致了信息检索领域的一场革命，是文档数据库研完的核心。全文检索的首要问题是全文检索模型的选择。本文介绍了目前国内外主要的全文检索模型，总结了全文检索模型的评价标准，按照此标准对各种模型进行了分析比较，并对全文检索模型构建中一些关键问题进行了分析。