基于C/S的消防安全管理信息系统总体设计

针对消防安全数据信息管理系统化的问题,且为了实现工作人员在不同工作场所的数据共享,将系统设计成客户机服务器即C/S模式。在系统需求分析的基础上,开展顶层数据流及客户端、服务器端数据库设计,解决了消防安全管理信息系统化及信息共享的问题。     

基于Micro830的异步电动机控制系统设计

为解决异步电动机的控制问题,本文利用Micro830PLC控制器和PowerFlex 4M变频器,构建了异步电动机控制系统,结合RsLinx和FactoryTalk View Studio软件,实现了上位机对整套电机控制系统的实时监控。同时利用RsLinx建立OPC通讯,并在FactoryTalk View Studio上利用已建立的OPC数据服务器进行上位机操作。经过对控制系统进行调试及运行,结果表明,监控软件可以实现电动机启动、停止、正反转的自由切换,响应速度快,能够实现有效地控制,整个控制系统稳定性和精确度较高,操作方便,上位机监控软件能实现转速和方向的实时显示和有效控制。该系统实现了异步电动机方向和转速的准确控制,具有良好的应用前景。     

Online algorithms for scheduling two parallel machines with a single server

We consider an online scheduling problem on two identical parallel machines with a single server. Jobs arrive one by one and each job has to be loaded by the server before being processed on one of the machines, and unloaded immediately by the server after its processing. Both loading and unloading times are equal to one time unit. The goal is to minimize the makespan. For the variant of the problem involving both loading and unloading operations, we present an online algorithm with competitive ratio of 5/3. For the variant with loading operation only, we show that the competitive ratio of list scheduling is at least 8/5 and provide an improved online algorithm with competitive ratio of 11/7. Finally, we discuss the lower bounds for these problems. We show that both variants have a lower bound of 3/2. Furthermore, we show that the lower bound of the first variant is at least 8/5 if the online algorithm satisfies a certain constraint.     

大数据处理中基于热感知的能源冷却技术

大数据极速发展使超大型大数据分析平台不断涌现,导致能源成本急剧上升。为保证服务器的热可靠性,提出一种以数据处理为中心的能源冷却成本技术。该技术考虑了服务器不均衡热力特性、热力稳定性负载阈值差异以及集群大数据语义差异等,对文件进行主动式热感知布局,从而在不影响性能的前提下降低冷却能源成本,保证大数据分析集群的热可靠性。基于Yahoo公司一个月的真实大数据分析对该技术进行评估,实验结果表明,该技术可使冷却成本下降42%,总体性能是当前无关冷却技术的9倍。     

一种可信第三方医学影像数据云平台身份认证

身份认证是云计算安全应用的挑战之一。针对Hadoop医学影像数据平台,提出改进的双服务器模型,并采用基于三角形原则的密码存储方法存储口令。其次,在该模型的基础上提出基于可信第三方的云存储架构。安全分析表明：基于双服务器模型的身份认证机制能够一定程度上改善口令认证的不足,加强口令存储安全,基于可信第三方的云存储架构能够实现用户信息管理和数据存储的分离,保护用户隐私。两者有机结合加强了医学影像平台的身份认证安全,防止攻击者访问云平台,窃取Dicom数据用于非法途径。     

服务器日志挖掘在电力业务系统功能推荐中的应用

提出了一种基于服务器日志挖掘的电力业务系统功能推荐服务,首先从电力业务系统服务器日志中获取用户日志数据,然后对含有"脏"数据的用户日志数据进行预处理,以适应数据挖掘与处理;接着由待处理的数据计算用户访问兴趣度,并基于改进的K均值聚类算法将用户访问兴趣度数据集划分为多个具有相近兴趣度的用户集合,最终为用户提供功能个性化推荐服务.实验结果证明该方法在实现电力业务系统信息推荐方面具有较好的效果.     

Karamanlidika Digital Library Proposal: Reconstructing the Past of a Specific Diaspora

ABSTRACT

The World Wide Web provides unlimited visibility for the personal documents and cultural artifacts that remain in the hands of families of people belonging to different diasporas. Computer mediated platforms are often the building blocks of their transcendental homelands. This article presents a study aiming to build a model and community around Karamanlides by using digital library technologies. Karamanlides is one of the many interesting communities in need of the creation of a “niche personal/community knowledge environment” as an archetype for similar conceptualizations.     

基于Web的网上作业系统设计与实现

按照网上作业平台系统实现目标,完成了系统功能性需求分析。对文件的数据库方式存储和文件系统方式的存储进行了比较,并分析、设计了本系统的存储结构。完成了数据库概念模型设计和数据表物理模型设计,详细给出了数据库关系图。设计并实现了基于Internet的课程网上作业子系统、个人网络硬盘子系统、课程资源库共享等子系统。该系统已经应用到日常的教学管理中,并取得了不错的效果。     

虚拟环境下Web服务动态负载均衡策略改进

为了提高Web服务集群的伸缩性和自动化能力,从虚拟化和负载均衡两方面研究集群系统,对现有负载采集策略做了改进,设计并实现了一种可根据负载值自动控制集群规模的模型XCluster。新模型运行在Xen提供的虚拟化环境中,实时监视宿主机层和虚拟机层的负载状态,随着集群系统总负载的增长,逐渐引入新的虚拟机来扩大集群规模,同时将任务合理分配到各个虚拟机节点上;当总负载下降时,逐渐关闭虚拟机缩小集群规模,释放出来的硬件资源又可以提供给其他集群系统使用。理论分析和实验结果表明,XCluster只需占用很少的网络通信量完成信息收集和命令下达,能够充分利用虚拟机易于管理的优势完成后端节点的调度,并且在任务总量相同的情况下,使用尽可能少的集群节点来执行任务。     

Query verification schemes for cloud-hosted databases: a brief survey

Database query verification schemes provide correctness guarantees for database queries. Typically such guarantees are required and advisable where queries are executed on untrusted servers. This need to verify query results, even though they may have been executed on one’s own database, is something new that has arisen with the advent of cloud services. The traditional model of hosting one’s own databases on one’s own servers did not require such verification because the hardware and software were both entirely within one’s control, and therefore fully trusted. However, with the economical and technological benefits of cloud services beckoning, many are now considering outsourcing both data and execution of database queries to the cloud, despite obvious risks. This survey paper provides an overview into the field of database query verification and explores the current state of the art in terms of query execution and correctness guarantees provided for query results. We also provide indications towards future work in the area.