基于DAI中间件的异构数据库集成

在研究异构数据库中数据集成的基本原理基础上,提出了数据库集成模型实现策略,即在异构数据库之间构建了一个中间层软件--"虚拟数据库系统",经授权认证的合法用户通过"虚拟数据库系统"提供的标准访问接口及统一数据格式对环境中各种分布的、异构的、不同种类的数据资源进行动态访问和集成.     

长庆油田勘探开发数据库安全系统分析与应用

为了有效预防重要敏感数据被窃取、篡改,通过对长庆油田勘探开发数据库加强信息资源安全审计管理,同时部署数据库安全插件,规范用户的数据库访问行为,较好地解决了勘探开发数据库系统的安全和管理问题,对数据库的安全起到了有效的监管作用.     

基于J-sim的主动结点资源访问控制策略实现

在主动节点资源访问控制上,设计了一种新的主动节点资源访问控制机制.提出利用权能对资源访问控制策略进行描述,动态维护.对用户的管理采用基于角色的方法.在主动信包中封装用户角色信息,主动节点解析出用户角色后,依据它在策略库中匹配相应的描述控制访问权限策略的方法,即权能.通过权能实现对节点资源的访问.并通过仿真试验验证了算法的有效性.     

鹰眼数据库审计系统--NDAS100/1000

目前,我国各政府部门、企事业单位使用的数据库系统绝大部分是由国外研制的商用数据库系统,其内部操作不透明,无法通过外部的任何安全工具来阻止内部用户的恶意操作、滥用资源、泄漏企业机密信息等行为.而数据库审计系统能很好地解决这一问题,它通过对网络数据的实时采集分析,监控来自网络内部和外部的用户对数据库的访问活动,及时识别和发现其中是否存在安全威胁和违规行为.系统的审计分析结果能帮助管理员对数据库安全策略进行分析,提升数据库安全性,并为管理员调整数据库安全策略、收集证据及事后追踪起诉提供有力的帮助.     

一种基于证书的登录控制实现

实施建立一套较好的登录控制机制,能够为用户提供统一的信息资源认证访问入口,建立统一的、基于角色和个性化的信息访问、集成平台。通过实施单点登录功能,使用户只需一次登录就可以根据相关的规则去访问不同的应用系统,提高信息系统的易用性、安全性、稳定性,并在此基础上进一步实现政府、企业用户高速协同办公。     

Internet网络中的代理访问技术

在Ｉｎｔｅｒｎｅｔ网络中，用户通过浏览器直接访问不同的站点资源。然而，大多网络站点所提供的信息都具有一定的更新频率，如每天、每周、每月甚至更长时间更新一次。如果用户每次访问都必须与对方站点直接建立连接，这不仅会大大增加用户的通信和访问费用，也降低了网...     

一个基于网格资源超市的计算网格资源管理模型

在现有的基于经济模型的网格资源管理方法中,用户共享资源访问一般经由网格用户代理实现,而资源提供者将资源交给网格资源代理处理,网格用户代理通过网格资源经纪访问网格资源代理,获取共享资源信息并使用共享资源。这类方法制约了用户直接选择使用共享资源,也限制了用户共享资源的范围、延长了作业运行周期。文章给出的基于网格资源超市的计算网格资源管理模型、共享资源访问流程及网格资源管理分配策略,较好地解决了这几个问题。     

PKI技术在电子政务中的应用

0 前言 随着计算机网络及应用在政府办公中的日益普及,"数字化公务员"将提上应用系统的建设日程:使一个具备数字化身份的用户可以随时随地访问授权的办公网络信息资源."数字化公务员"的实现首先需要对用户进行全网统一的身份认证和对全网的信息资源进行属性定义、密级划分,以确定用户身份和资源访问权限之间的对应关系,实现访问控制.达到这一目标的关键是建设适合电子政务信息系统和运用特点的PKI系统.     

信息网格门户的研究

网格门户提供了一个访问网格环境的Web界面．当前存在的网格门户主要是基于计算网格的环境而设计，因此门户设计的重点是文件访问，提交任务，监控任务的执行，从而达到简化研究人员访问网格计算资源的目的．信息网格是在网格基础上的为用户提供信息的平台，通过信息网格门户用户可以无缝的获取所需要的信息．本文以上海网格为背景着重对信息网格门户的特点以及网格资源管理、工作流、事务进行分析和研究．     

基于PKI的铁路门户单点登录系统的实现

针对目前铁路部门业务管理效率低下,现有信息资源得不到充分利用,信息系统缺乏统一的身份安全认证等问题,本文设计了一种适合的单点登录系统和个性化门户。采用PKI、CA、LDAP等技术为用户提供了统一的信息资源认证访问入口,建立了统一的、基于角色的和个性化的信息访问集成平台,用户只需一次登录就可以根据相关的访问权限和策略设置规则去访问不同的应用系统,单点登录系统的设计加强了各业务子系统的交互性、整体性和数据的互通共享,解决了企业的信息孤岛问题,为用户提供了快捷有效的信息服务和专家决策支持。     

Integrating Spatial and Temporal Relationship Operators into SQL3 for Historical Data Management

A spatial object changes its states over time. However, existing spatial and temporal database systems cannot fully manage time-varying data with both spatial and nonspatial attributes. To overcome this limitation, we present a framework for spatio-temporal databases that can manage all time-varying historical information and integrate spatial and temporal relationship operators into the select statement in SQL3. For the purpose of our framework, we define three referencing macros and a history aggregate operator and classify the existing spatial and temporal relationship operators into three groups: exclusively spatial relationship operators, exclusively temporal relationship operators, and spatio-temporal common relationship operators. Finally, we believe the integration of spatial and temporal relationship operators into SQL3 will provide a useful framework for the history management of time-varying spatial objects in a uniform manner.     

军械装备保障模拟训练系统数据集成研究

现行的军械装备保障模拟训练系统的后台数据库多种多样,数据存储的格式和为前台提供的服务方式不尽相同,致使信息在不同部门和系统之间流通困难,分散的系统很难促进军械装备保障能力快速提高。介绍了一种数据集成模式——基于数据仓库的数据集成。采用该数据集成模式,可以屏蔽各种数据库中数据存储的差异,解决模拟训练分系统数据共享和交换的问题,实现分系统数据的互联互通,为实现军械装备保障模拟训练系统集成提供数据保障。     

支持CSCW的多数据库技术

计算机支持的协同工作（CSCWComputerSupportedCooperativeWork）所涉及的应用离不开数据库，而许多数据库是在此之前早已存在的。已有数据库具有多态性、分布性和自治性，为了实现这些数据库之间的共享，文章提出用多数据库的技术来扩展早些时期的分布式数据库技术，并对多数据库的关键技术：多数据库的结构模式、公共数据模型、多数据库查询语言、多数据库事务管理和多数据库完整性约束等加以讨论。     

Semantics in Image and Video Retrieval Systems

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MCYT baseline corpus: a bimodal biometric database

The current need for large multimodal databases to evaluate automatic biometric recognition systems has motivated the development of the MCYT bimodal database. The main purpose has been to consider a large scale population, with statistical significance, in a real multimodal procedure, and including several sources of variability that can be found in real environments. The acquisition process, contents and availability of the single-session baseline corpus are fully described. Some experiments showing consistency of data through the different acquisition sites and assessing data quality are also presented.     

远程数据采集与监控系统在冶金行业中的应用研究

在冶金行业中，对生产效率及生产质量的要求越来越高，应积极应用远程数据采集与监控系统。例如，在钢厂自动化部钢区构建数据平台，以iHistorian实时数据库为支撑，通过DCS和PLC基础自动化系统，对毫秒级的历史、实时数据进行采集。同时，其还能对手工录入的Excel表格中的数据、安全健康体系和环境体系数据进行采集。iHistorian实时数据库的特点是开放性较强，能对ODBC加以支持。对于关系型数据库支持下的各种系统，其均可提供有价值的数据，从而获得决策依据。     

The Role of Artificial Intelligence in the Integration of Remotely Sensed Data with Geographic Information Systems

Although databases for geographic information systems (GIS) have been developed to manage digital map data, the integration of remotely sensed imagery and other collateral non-map information is rarely performed. For the most part, the use of sophisticated intelligent spatial databases, in which the user can query interactively about map, terrain, or associated imagery, is unknown in the GIS and cartographic community. In standard GIS systems, the ability to formulate complex queries requiring dynamic computation of factual and geometric properties is severely limited, often reflecting its origin as collections of thematic map overlays. Spatial database research requires the integration of ideas and techniques from many disciplines such as computer graphics, computational geometry, database methodology, image analysis, photogrammetry, and artificial intelligence. In this paper we discuss some ideas on how the scope of geographic information systems can be expanded by utilizing techniques from the Al community that may remedy deficiencies in user interfaces, spatial data representation, and its utilization. We draw on ongoing research at Carnegie Mellon University for examples of these techniques in the areas of image/map database and knowledge-based image interpretation.     

Complex life science multidatabase queries

Recent advances in the development of new, high throughput screening technologies have resulted in a wealth of life science data. The complexity and volume of these data require technology beyond that of traditional database systems. Open research issues include the seamless, semantic-based integration of geographically distributed, autonomous web databases. Biological And Chemical Integration Information System (BACIIS) addresses these issues. This paper discusses the challenges associated with the integration of life science web databases and the techniques used in BACIIS to address these challenges. Particularly, the execution of life science, multidatabase queries is investigated, and an approach that can overcome the limitations of the query capabilities of each individual life science web database participating in the integration is presented. This approach hides the heterogeneity of the individual databases from the user while providing an efficient execution plan for complex, life science, multidatabase queries.     

Influencing public policy through information sharing

The data collected in electronic databases by government agencies, universities, and private organizations could be of use to a public increasingly interested in participating in public policy formation. However, because most users lack skill in communicating with computers and because institutions resist the dissemination of databases, this information is not widely accessible to the public in forms it can use. The authors propose establishing a public access `data hub' to process requests for database access, download a copy of the requested data from the original source database (databases would not reside at the hub), and display the data in the form requested. The `bridge' between user and data would be an interface to process the request for data and then shape and interpret the data for the user. A single interface would allow users access to information that resides on many different computers without their having to learn to `talk' to each different system. Helping to design and implement this interface would be the task of the professional communicator     

A Distributed Framework for Parallel Data Mining Using HPJava

Java has become a language of choice for applications executing in heterogeneous environments utilising distributed objects and multithreading. To handle large data sets, scalable and efficient implementations of data mining approaches are required, generally employing computationally intensive algorithms. Conventional Java implementations do not directly provide support for the data structures often encountered in such algorithms, and they also lack repeatability in numerical precision across platforms. This paper describes a distributed framework employing task and data parallelism, and implemented in high performance Java (HPJava). Issues of interest for data mining algorithms are identified, and possible solutions discussed for overcoming limitations in the Java Virtual Machine. The framework supports parallelism across workstation clusters, using the message-passing interface as middleware, and can support different analysis algorithms, wrapped as Java objects, and linked to various databases using the Java database connectivity interface. Guidelines are provided for implementing parallel and distributed data mining on large data sets, and a proof-of-concept data mining application is analysed using a neural network.