基于谱正则化算法的大数据矩阵完备化研究

矩阵完备化是基于部分观测数据来完成全部矩阵预测的问题.随着互联网技术的发展,大数据时代的来临,大数据矩阵中大多数据依然是空白的,需要补充,即大数据存在矩阵完备化的问题.本文利用谱正则化模型和算法来解决大数据的矩阵完备化问题,该方法将矩阵完备化问题整理成核范数最小二乘问题,再通过截断奇异值分解、软输入算法和硬输入算法给出了一系列正则化低秩解.最后基于实际的Netflix 大数据的实验结果证明了本文的方法.     

异构数据的形成及数据集成技术分析

提供了一个基于Java和XML的数据的集成模型,为异构数据的集成提供了一个与数据库系统无关、与操作系统无关的简单方便的解决方案．根据这一模型开发的信息系统,可以实现数据在不同操作系统、不同数据库系统、不同网络平台和不同开发语言的数据库进行应用．     

城市突发公共事件应急管理平台的实现

城市应急突发公共事件管理平台需要解决各参与者的信息有效对接和统一规范的应急信息技术标准,因此,在实现过程中,采用发言权控制机制实现信息共享,使用Row Set的数据集结构实现统一的数据交换标准。实践表明,系统的实现很好地推进了应急管理的研究。     

Development of a middle and low latitude theoretical ionospheric model and an observation system data assimilation experiment

On the basis of previous work, we develop a middle and low latitude theoretical ionospheric model in this paper, named Theoretical Ionospheric Model of the Earth in the Institute of Geology and Geophysics, Chinese Academy of Sciences （TIME-IGGCAS）. TIME-IGGCAS solves the equations of mass continuity, motion and energy of electron and ions self-consistently and uses an eccentric dipole field approximation to the Earth＇s magnetic field. We combine the Eulerian and Lagrangian approaches in the model and take account of the plasma ExB drift velocity. Calculation results reveal that the model is steady and credible and can reproduce most large-scale features of ionosphere. By using TIME-IGGCAS, we carried out an observation system data assimilation experiment. Assimilation results show that the ExB drift velocity can be accurately estimated by ingesting the observed foF2 and hmF2 into the model applying nonlinear least-square fit method. We suggest that this work is of great significance in the development of ionospheric data assimilation model to give better nowcast and forecast of ionosphere.     

On Peer-Assisted Data Dissemination in Data Center Networks: Analysis and Implementation简

Data Center Networks （DCNs） are the fundamental infrastructure for cloud computing. Driven by the massive parallel computing tasks in cloud computing, one-to-many data dissemination becomes one of the most important traffic patterns in DCNs. Many architectures and protocols are proposed to meet this demand. However, these proposals either require complicated configurations on switches and servers, or cannot deliver an optimal performance. In this paper, we propose the peer-assisted data dissemination for DCNs. This approach utilizes the rich physical connections with high bandwidths and mutli-path connections, to facilitate efficient one-to-many data dissemination. We prove that an optimal P2P data dissemination schedule exists for FatTree, a specially- designed DCN architecture. We then present a theoretical analysis of this algorithm in the general multi-rooted tree topology, a widely-used DCN architecture. Additionally, we explore the performance of an intuitive line structure for data dissemination. Our analysis and experimental results prove that this simple structure is able to produce a comparable performance to the optimal algorithm. Since DCN applications heavily rely on virtualization to achieve optimal resource sharing, we present a general implementation method for the proposed algorithms, which aims to mitigate the impact of the potentially-high churn rate of the virtual machines.     

一种基于粗糙集的数据分类方法

应用粗糙集理论的属性约简和规则约简方法对数据进行分类,并以可靠的数据对该方法进行了实验.结果表明,该方法复杂度低,且能有效提高分类效果.     

数据仓库清洗技术讨论

数据仓库建设过程中最关键的环节是数据集成,本文重点分析了数据清洗需要解决的问题及涉及的主要技术,针对数据库的数据模型与数据仓库模型的区别讨论了利用元数据的映射规则的数据清洗方法.     

电脑商场

正有一个电脑商场,坐落在城市的西郊。商场里安装了许多电脑,商场里的一切物品都由一台电脑总机——中控电脑指挥。商场的大门上方装有一个大电路盘,将商场内各个角落的电脑相连,并将商场的相关数据输入中控电脑,为商场的有序管理提供     

基于两因子间相互约束的实验设计方法

针对实验设计中可控因子间存在相互约束的问题,讨论了在存在约束的条件下如何选取实验的可控因子水平构造计划矩阵,选而收集、分析实验数据．主要研究了两因子间存在约束关系的情况,通过引入自由因子和对实验中缺失数据点的处理,将不规则的实验区域变换为规则的实验设计区域,从而使存在约束问题的实验设计转化成为经典的实验设计,为两因子间存在约束的实验设计问题提供了可行的解决方案．     

Web应用开发技术的发展前景

通过回顾Web应用开发技术的发展历史和对目前各种Web应用开发技术的探讨和比较,揭示出当前互联网上Web应用开发技术无法满足社会生产和生活需求的原因。并针对不同的原因提出了若干解决问题的方案。