基于机群系统的并行多连接查询优化算法

多连接查询优化是并行数据库系统的核心问题。已有的研究工作多集中于连接个数较少的情况,不适用于机群系统中的多连接查询优化。在机群环境中,系统的通信带宽是一种瓶颈资源。提出了基于遗传算法的多连接查询优化算法,算法考虑了关系的存储信息和网络的通信代价,有效地利用了机群系统中的资源。实验结果表明,算法具有良好的性能,能够提高多连接查询的执行效率。     

基于查询扩展和分类的信息检索算法

文本信息检索是处理海量文本的重要手段之一，针对短查询串中出现的查全率高但查准率低的问题，引入一种基于查询扩展和分类的信息检索算法。该算法在检索的第一阶段利用自动相关反馈方法扩展用户递交的短查询串增加查询信息，在第二阶段使用文本分类技术辅助检索。分析和实验结果表明：新的算法比传统的查询扩展检索算法具有更好的查准率和查询效率。     

Multidimensional Data Querying on Tree-Structured Overlay

Multidimensional data query has been gaining much interest in database research communities in recent years, yet many of the existing studies focus mainly on ten tralized systems. A solution to querying in Peer-to-Peer（P2P） environment was proposed to achieve both low processing cost in terms of the number of peers accessed and search messages and balanced query loads among peers. The system is based on a balanced tree structured P2P network. By partitioning the query space intelligently, the amount of query forwarding is effectively controlled, and the number of peers involved and search messages are also limited. Dynamic load balancing can be achieved during space partitioning and query resolving. Extensive experiments confirm the effectiveness and scalability of our algorithms on P2P networks.     

网络设备管理信息系统查询模块的拓展方案与设计

在对现有网络设备管理信息系统的查询模块分析的基础上进行功能延伸，提出了新型有效的查询模块拓展方案，阐述了模块的功能和设计流程，并给出了实现方案．     

OGSA-DQP体系结构及其关键技术研究

介绍了OGSA-DAI的体系结构,分析了OGSA-DQP的功能和应用模型,详细讨论了OGSA-DQP接收和响应分布式数据查询请求的执行流程,并给出了应用关键技术的实例。     

一种问答式检索系统布尔查询生成方法

提出了一种基于简单语法分析的问答系统查询生成方法，利用对问题的词性标注，形成初始化布尔查询，根据查询结果文档集对查询迭代调整，最终产生合理的布尔查询. 通过TREC2004和TREC2005的QA TRACK数据集上的实验，表明该方法在没有增加很大复杂度（平均迭代2.5次）的情况下大大提高了平均查准率，覆盖率和重复率.     

数据库加密通用接口插件的研究与实现

从数据库加密入手，讨论了数据库的加密存储模型、密文数据库的密文查询和客户端SQL语句的分析，并在此基础上实现了数据库加密通用接口插件，用户可应用此接口进行数据库应用程序开发．     

Query Translation on the Fly in Deep Web Integration

To facilitate users to access the desired information, many researches have dedicated to the Deep Web （i.e. Web databases） integration. We focus on query translation which is an important part of the Deep Web integration. Our aim is to construct automatically a set of constraints mapping rules so that the system can translate the query from the integrated interface to the Web database interfaces based on them. We construct a concept hierarchy for the attributes of the query interfaces, especially, store the synonyms and the types （e.g. Number, Text, etc.） for every concept At the same time, we construct the data hierarchies for some concepts if necessary. Then we present an algorithm to generate the constraint mapping rules based on these hierarchies. The approach is suitable for the scalability of such application and can be extended easily from one domain to another for its domain independent feature. The results of experiment show its effectiveness and efficiency.     

A Personalized Microbe Biodiversity Dataspace Information System

It can not provide dynamic view mechanism in previous dataspace information system. In this paper, the dynamic extendable view mechanism provided by object deputy model is proposed for personalized dataspace information system which can provide rich semantics and enough flexibility. The flexible inheritance avoids a lot of data redundancy. The cross class query mechanism allows users to find more related data based on complex relationships. The personalized dataspace service provides less storage space consumption and shorter query response time. The experiment result shows that our approach is more feasible and efficient than the traditional one.     

运用SQL快速审计产成品成本

以审计产成品为例，介绍了从三个方面入手的查询方案：一是从实物流转与成本流转是否一致入手，二是从非法对应科目入手，三是从是否虚构成本入手，并结合用友财务软件进行分析说明。