图形数据库的面向对象的模糊检索算法

现有的确定检索算法不能控制图形数据库中查询对象的范围和行为,更不能解决对象的精确查询问题。为了解决这个问题,提出了面向对象的不确定检索方法。对检索对象建立了模糊层次对象树,给出了非线性模糊因子计算公式,设计了模糊对象检索算法。检索过程中用概念化的模型组织数据,用不确定的特征去检索数据,有效地控制了查询时对象的范围和行为．实现了对象的精确查询。     

基于SQL的模糊查询技术研究与实现

SQL已经被用户和业界广为接受并成为国际标准.但是,SQL只能表示和处理精确数据,where处的查询条件必须是明确的数值,无法表达自然语言中的模糊概念.本文针对具体人员信息数据库,将模糊数学理论与数据库系统相结合,提出了基于人员年龄,身高和体重的模糊单词、模糊隶属函数、模糊算子的表达式,并通过算式将模糊化的概念转换为相应的SQL语句,提供了两种基于模糊算法的人员信息数据库查询方法(正向法和反向法),并设计出了良好的查询工具.     

基于用户反馈的关系数据库关键字查询系统

关系数据库中的关键字查询问题使得用户无需掌握查询SQL语言与数据库模式相关知识就可以进行数据库查询,因此受到人们的广泛关注,许多方法和原型被提出。当前流行的关系数据库中关键字查询技术存在较慢的查询时间或者不准确的查询结果。针对这两个问题,提出了一种基于用户反馈的查询方法,根据用户输入的关键字动态地生成一个在数据库中包含关键字的属性所组成的Form表单提供给用户,用户在Form中进行选择并提交,最后,根据用户的选择和数据库模式图进行连接算法并执行SQL获得最终结果。     

基于SQL中的查询优化策略研究

查询是数据库中最基本、最常用、最复杂的操作,查询操作的优劣直接影响数据库应用程序的性能.为了提高数据库应用系统的执行效率,本文以关系数据库为基础,从分析关系数据库系统查询处理过程入手,结合自己的实践经验,从数据库设计和查询策略选择的角度来讨论查询优化技巧,指出关系数据库查询优化的一般原则.本文主要讨论了基于SQL查询重写技术的数据库查询优化策略,通过查询重写可以把用户所写的效率不高的SQL语句重新优化组合,使之成为效率较高的查询语句.     

模糊查询在电子商务数据库查询中的应用

为了在当前的电子商务关系型数据库上实现数值上的模糊查询,将模糊逻辑理论引入数据库的查询中,分析数据并建立隶属函数.从而使关系型电子商务数据库在经过调整后支持数值上的模糊查询.给出了建立模糊数据库的实现过程,对模糊数据库进行查询并给出实验结果.结果证明由关系型数据库转为模糊数据库后性能相近,可行性高.     

模糊逻辑在数据库关键字查询中的应用研究

关键字查询技术作为数据库(DB)信息检索的一个研究方向,构成了信息获取的基础,是实现用户与数据之间智能交互的前提。然而由于用户使用语言的灵活性,使其提交的查询意图具有模糊性或不精确性,因此数据库中的模糊查询成为了信息检索领域的重要研究方向。首先简单介绍了模糊逻辑的相关理论知识,然后重点介绍近年来模糊逻辑在关系数据库关键字查询中的应用,分为基于元组级别和对象级别的模糊查询两类,及Top-k排序方法。最后通过对国内外模糊逻辑应用进行研究,给出了该技术的发展趋势和新的挑战。     

基于模糊数据库的数据查询研究

在现实生活中查询对象既有确定性数据也有大量模糊性数据，现有传统查询技术已无法满足此要求。文章将模糊理论与数据库系统相结合，得到一种数据查询新技术。在介绍了模糊查询和模糊数据的表示之后，提出了建立基于可能性的模糊数据库。并应用于实例中，构筑了在模糊数据库中实现查询的理论和实践框架。     

Deep Web数据库的选择

Web中存在大量可以访问的在线数据库,如何快速准确地选择出与用户查询相关的数据库变得越来越重要。如果只是简单地把集成接口上的查询转换到对该领域每个数据库的查询,那么要访问该领域的每个数据库将花费大量的代价,并且一个领域中大部分的数据库之间存在着冗余的信息,这样查询结果也会产生大量的信息冗余。本文给出了基于TOP-N查询的数据库选择方法,并对其不相关度距离计算和数据库选择方法进行了改进,使得在数据库选择中减少了资源的浪费,提高了选择查询性能。     

基于网络共享的材料性能数据库系统

针对材料性能数据管理的需求，文中提出一种材料性能数据网络共享方案，该设计包括材料性能数据采集、数据查询、数据分析、数据可视化以及数据安全管控模块的材料性能数据库系统，能解决现有材料性能数据库网络化共享不足、数据融合及多学科支持不足、智能化服务不足、标准化不足和数据安全管控不足等问题。采用分级访问控制策略，用户登录系统后对材料性能数据进行标准化处理并存储，形成共享材料性能数据库；再对存储的标准化处理后的材料性能数据按照权限进行受控查询共享，对受控查询共享得到的材料性能数据进行对比分析；最后，对得到的受控查询共享结果和得到的对比分析结果进行可视化展示。数据库系统采用基于B/S跨平台J2EE的MVC架构集成第三方计算平台，用户通过浏览器及网络可方便使用材料性能数据及相关服务；数据库采用MongoDB，支持分布式存储及高效查询。     

基于领域样本查询的Deep Web数据库分类

提出了一种基于领域样本查询的方法以分类这类Web数据库.通过分析领域的高级查询接口自动获取领域主属性并使用领域知识为主属性构建查询样本,然后对查询接口提交试探查询,根据返回结果页面的结果模式和记录内容估计Web数据库与领域的相关程度.通过在多个领域的Web数据库上进行实验验证,说明该方法分类只提供简单查询接口的Web数据库是有效的,取得了较高的分类精确率,召回率和F-measure值.     

BilVideo: a video database management system

The BilVideo video database management system provides integrated support for spatiotemporal and semantic queries for video. A knowledge base, consisting of a fact base and a comprehensive rule set implemented in Prolog, handles spatio-temporal queries. These queries contain any combination of conditions related to direction, topology, 3D relationships, object appearance, trajectory projection, and similarity-based object trajectories. The rules in the knowledge base significantly reduce the number of facts representing the spatio-temporal relations that the system needs to store. A feature database stored in an object-relational database management system handles semantic queries. To respond to user queries containing both spatio-temporal and semantic conditions, a query processor interacts with the knowledge base and object-relational database and integrates the results returned from these two system components. Because of space limitations, we only discuss the Web-based visual query interface and its fact-extractor and video-annotator tools. These tools populate the system's fact base and feature database to support both query types.     

A Tool for Query Formulation based on Entities and Roles

In order to formulate valid queries on a relational database, one must be fluent in SQL (Structured Query Language), the concepts that it involves (entities, relationships, attributes) and the data schema describing the elements of the domain. However, casual users are not familiar with query languages and database structures, but would like to access data in a more user friendly way. The goal of this paper is to present a query formulation tool that allows casual users to easily build a query using an almost natural language, on a step by step basis, guided by the tool.     

Supporting conceptual and neighborhood queries on the World WideWeb

A document retrieval system mainly consists of three components: document representation, user queries, and document evaluation. Each component may involve some uncertainties. Fuzzy set theory is a natural approach to coping with the representation of documents, queries, and the relevance of documents to a given query. The authors propose a fuzzy document retrieval model on the World Wide Web (WWW) environment to support conceptual queries. A flexible query expression is proposed to support different semantics of the queries. A concept network is adopted as the knowledge base to represent the relevance of the concepts. The concept network is explored from the WWW. Moreover, they also support neighborhood queries, which retrieve documents relevant to a document specified by a user. A system is currently being implemented to achieve these functions     

SQLS: A Storm-Based Query Language System for Real-Time Stream Data Analysis

In this work,a Storm-based query language System (SQLS) is proposed for real-time data stream analysis.The system is compatible with Continuous query language (CQL) specification.It supports both continuous queries and one-time queries over streaming data,and meets the requirements of user experience (traditional SQL queries) and QoS (such as real-time and throughput).In order to better meet the requirement of throughput and enhance the processing efficiency,the load shedding algorithm and cache optimization are employed during the implementation of SQL-like operators.Finally,performance testing of the proposed SQLS has been conducted on standalone Storm platform and Storm clusters.Experimental resuits show that our system can not only meet the needs of users,but also extend the function of real-time streaming queries processing.     

Introduction to the Special Issue on Communication Issues in User–Database Interaction

Research on user–database interaction studies the communication issues among users with various roles, such as end-user, requirement analyst, database designer, query programmer, as well as between users and databases through various database management systems. Many topics are included. Common topics include the formal languages used in database models and queries, with focus on designer and user writing effectiveness and efficiency, as well as end-user comprehension and problem solving capabilities. Research results are generally applicable to the communication processes for users, user training, and the design of database management systems, such as query interfaces and choice of database models.     

Research on LBS privacy preservation based on pseudorandom permutation in road network

A method of privacy preservation based on pseudorandom permutation was put forward for the issues of location privacy and query content privacy.Firstly,the distribution information of points of interest (PoI) based on the vertexes in the road network was organized,each single road vertex was taken as the foundational processing object.Based on the pseudorandom permutation,a permutation scheme of the point-of-interest records at the LBS server's end was put forward,a 32-bit random seed was adopted to generate a permuted table in the scheme,and the point-of-interest records were encrypted and permuted according to the table.These processed records were stored in the LBS database.Then a trusted intermediate server,replacing of the user,issued a query request with a record number instead of the query content to the LBS server.The LBS server could not determine which kind of PoI the user was interested in or which road section the user was locating on,and therefore the scheme achieved private information retrieval.Finally,the efficiency in the metrics of query accuracy,communication overhead and processing time was also analyzed.By the performance analysis and extensive experiments,the proposed scheme is proved to be location untraceable and query content uncorrelation.     

Query Acceleration of Graph Databases by ID Caching Technology

In this paper, we approach the design of ID caching technology (IDCT) for graph databases, with the purpose of accelerating the queries on graph database data and avoiding redundant graph database query operations which will consume great computer resources. Traditional graph database caching technology (GDCT) needs a large memory to store data and has the problems of serious data consistency and low cache utilization. To address these issues, in the paper we propose a new technology which focuses on ID allocation mechanism and high-speed queries of ID on graph databases. Specifically, ID of the query result is cached in memory and data consistency is achieved through the real-time synchronization and cache memory adaptation. In addition, we set up complex queries and simple queries to satisfy all query requirements and design a mechanism of cache replacement based on query action time, query times, and memory capacity, thus improving the performance furthermore. Extensive experiments show the superiority of our techniques compared with the traditional query approach of graph databases.     

Trajectory privacy protection method based on location obfuscation

In the process of continuous queries,a method of trajectory privacy protection based on location obfuscation was proposed to solve the problem that K-anonymity was difficult to guarantee user privacy in third party architectrue.Firstly,the (G-1) query obfuscation locations through the location prediction was obtained and the dummy location selection mechanism,and then sent them together with the user’s real query location to different anonymizers to form cloaking regions and sent them to the LBS server for queries,and the query results were returned to the user by different anonymizers.In this method,the user’s real query location was confused by the location obfuscation,and the attacker couldn’t deduce the user’s trajectory from a single anonymizer or the LBS server.The method can enhance the privacy of the user’s trajectory and can effectively solve the performance bottleneck in the single anonymizer structure.Security analysis shows the security of the proposed approach,and experiments show this method can reduce the number of interactions between the user and the LBS server and the overhead of the single anonymizer.     

An Efficient PAB‐Based Query Indexing for Processing Continuous Queries on Moving Objects

Existing methods to process continuous range queries are not scalable. In particular, as the number of continuous range queries on a large number of moving objects becomes larger, their performance degrades significantly. We propose a novel query indexing method called the projected attribute bit (PAB)‐based query index. We project a two‐dimensional continuous range query on each axis to get two one‐dimensional bit lists. Since the queries are transformed to bit lists and query evaluation is performed by bit operations, the storage cost of indexing and query evaluation time are reduced significantly. Through various experiments, we show that our method outperforms the containment‐encoded squares‐based indexing method, which is one of the most recently proposed methods.