Semantic integrity support in SQL:1999 and commercial (object-)relational database management systems

The correctness of the data managed by database systems is vital to any application that utilizes data for business, research, and decision-making purposes. To guard databases against erroneous data not reflecting real-world data or business rules, semantic integrity constraints can be specified during database design. Current commercial database management systems provide various means to implement mechanisms to enforce semantic integrity constraints at database run-time. In this paper, we give an overview of the semantic integrity support in the most recent SQL-standard SQL:1999, and we show to what extent the different concepts and language constructs proposed in this standard can be found in major commercial (object-)relational database management systems. In addition, we discuss general design guidelines that point out how the semantic integrity features provided by these systems should be utilized in order to implement an effective integrity enforcing subsystem for a database. Received: 14 August 2000 / Accepted: 9 March 2001 / Published online: 7 June 2001     

An Automated Fault Diagnosis System Using Hierarchical Reasoning and Alarm Correlation

The increasing importance of computer networks in this information age demands a high level of network availability and reliability. As we become more dependent on networks in our so-called cyber-world, network faults and downtime become very costly. Sometimes, a slight fault may cause critical disruptions or remediless damages to the network while the network manager is lost among a large amount of alarm messages. Therefore, the development of a practical and effective system for network fault diagnosis becomes an imperative and critical task. In this paper, we develop a hierarchical domain-oriented reasoning mechanism suitable for the delegated management architecture. It is based on the causality graph of a refined network fault propagation model as a result of our empirical study. An automated fault diagnosis system called Alarm Correlation View (or ACView) for isolating network faults in a multi-domain environment is proposed according to the hierarchical reasoning mechanism. This diagnosis system not only provides the process of automated alarm collection and correlation, but also serves the function of efficient fault localization and identification. Furthermore, an alarm-to-fault mapping strategy is used to enhance the fault reasoning capability for uncertain network fault propagation.     

天然产物样品的高通量制备技术

自动化制备高质量和足够数量的样品是进行高通量筛选天然产物的前提 ,是发现新生物活性分子的关键步骤之一。通过基于固相萃取或高效液相 /固相萃取联用的自动化方法制备天然产物样品 ,制得的样品质量和数量能够满足高通量筛选天然产物的需要。     

石家庄经济技术开发区污水处理厂自动化运行

对石家庄经济技术开发区污水处理厂进行了概述,详细地介绍了该污水处理厂的自动化控制系统,探讨了污水处理工艺流程及自动化控制过程,得出了该污水厂运行安全稳定的结论,以促进污水处理工艺的发展。     

自动化立体仓库堆垛机精确控制技术的研究

介绍自动化立体仓库的系统组成结构、工作流程、位置控制技术。结合机电一体化技术,完成了自动化立体仓库巷道堆垛机行走机构、升降机构、伸缩货叉机构PLC控制系统设计。着重说明PLC在自动化立体仓库堆垛机精确控制方面的应用。     

全自动动平衡机设计与动态分析

设计了一种用于检测电机转子的全自动动平衡机。其与现有的平衡机结构相比增加了自动平衡装置,该装置通过调整共面的两平衡块的相对位置,在给定半径时,可以确定不平衡量的相位角。在结构上,对其进行了合理的设计并校核强度,以满足设计需求。安装了自动平衡装置的动平衡机可实现在线平衡。另外,还对平衡机整机进行动态分析,识别出系统的模态参数,找出薄弱环节,为以后的结构优化作好准备。     

考虑电池包数量的自动化集装箱码头多AGV调度优化

针对自动化集装箱码头自动引导小车（automated guided vehicle,AGV）的实际换电特性,为了降低AGV的总任务完成时间和换电总时间,合理规划换电站内的电池包数量,建立了双层规划模型。首先考虑AGV的电池续航、空重载SOC变化特性和不同剩余电量与速度变化,以降低AGV的总任务完成时间为目标,构建考虑换电的多AGV集装箱任务调度上层模型。在此基础上,为了合理规划换电站内的电池包数量,考虑自动化码头中换电站的实际电池包选取原则和换电流程,对换电站和电池包的选择进行决策,以降低换电总时间为目标,构建换电电池包配置下层模型。最后通过遗传算法分别对小规模和大规模算例进行求解。算例结果表明,此双层规划模型能够有效地减少总任务完成时间和换电总时间,提高了6.46%的AGV利用率,减少了23.1%的换电站电池包数量。     

私有云平台下基于性能感知的自动化管理框架研究

与公有云不同,私有云大都由各个企业单独建立,因此如何对私有云的基础设施进行高效管理,真正实现资源的集中管理、按需分配成为企业搭建私有云平台时面临的挑战。本文提出一种基于性能感知的自动化管理框架,对私有云平台下基础设施进行管理,框架监控云平台的实时运行状态,根据运行状态动态调整资源的分配,实验表明该框架可以有效地对私有云的基础设施进行管理。     

VR在雷达情报自动化系统维修训练中的应用

为了满足在雷达情报自动化装备维修教学训练中实现“实时”、“实地”、“实装”训练效果的需求,在构建的三维虚拟维修环境中,利用VRML的Script点实现基于标准外设的人机交互,建立了雷达情报自动化装备维修训练系统．通过在实际教学中的初步应用,有效地解决了训练受场地、时间的限制和消耗成本较高的问题．     

基于Blended Learning的协作型网络课程设计

网络课程是立体化教学资源建设的重要组成部分。如何将网络课程与传统课堂教学有机结合,是立体化教学资源建设的关键。文章就如何发挥Blended Learning的优势,构建协作型网络课程,提出了相应的设计原则。在网络课程内容展示上,强调任务驱动的教学设计：在课程实施策略上,以项目驱动的学习情景策略为主线,并通过一系列的保障策略,最终实现功能强大、实用的协作型网络课程。