Long-term digital preservation: preserving authenticity and usability of 3-D data

Long-term digital preservation, the process of maintaining digital objects through time to ensure continued access, has become a crucial issue in recent years. Whilst the amount of digitised information is constantly increasing, so too is the pace of progress in information technology, resulting in obsolescence of the software and hardware required to access and view digital information. Despite many organisations recognising this threat and the resulting need for preservation action, more work is required to effectively address the issue. We present in this article a framework for the long-term digital preservation of 3-D data. This framework is based on two pertinent preservation practices, emulation and metadata which ensure that the authenticity and usability, respectively, of a preserved digital object remain intact through time. An evaluation of our framework is presented which illustrates the viability of our approach in retaining accessibility, authenticity and usability for future end users.     

基于分布式结构的网络恶意代码智能分析系统

对变形特征码进行归一化处理,改进WM算法,运用启发式扫描、仿真、虚拟化、主动防御等前沿的恶意代码分析技术,采用分布式的设计结构,设计了具有完备恶意代码特征码数据库、高效特征码匹配、自动捕获和控制恶意行为、平衡的资源消耗、较低误报率的网络恶意代码智能分析系统。     

Architecture for the next generation system management tools

To get more results or greater accuracy, computational scientists execute their applications on distributed computing platforms such as clusters, grids, and clouds. These platforms are different in terms of hardware and software resources as well as locality: some span across multiple sites and multiple administrative domains, whereas others are limited to a single site/domain. As a consequence, in order to scale their applications up, the scientists have to manage technical details for each target platform. From our point of view, this complexity should be hidden from the scientists, who, in most cases, would prefer to focus on their research rather than spending time dealing with platform configuration concerns.In this article, we advocate for a system management framework that aims to automatically set up the whole run-time environment according to the applications’ needs. The main difference with regards to usual approaches is that they generally only focus on the software layer whereas we address both the hardware and the software expectations through a unique system. For each application, scientists describe their requirements through the definition of a virtual platform (VP) and a virtual system environment (VSE). Relying on the VP/VSE definitions, the framework is in charge of (i) the configuration of the physical infrastructure to satisfy the VP requirements, (ii) the set-up of the VP, and (iii) the customization of the execution environment (VSE) upon the former VP. We propose a new formalism that the system can rely upon to successfully perform each of these three steps without burdening the user with the specifics of the configuration for the physical resources, and system management tools. This formalism leverages Goldberg’s theory for recursive virtual machines (Goldberg, 1973 [6]) by introducing new concepts based on system virtualization (identity, partitioning, aggregation) and emulation (simple, abstraction). This enables the definition of complex VP/VSE configurations without making assumptions about the hardware and the software resources. For each requirement, the system executes the corresponding operation with the appropriate management tool.As a proof of concept, we implemented a first prototype that currently interacts with several system management tools (e.g., OSCAR, the Grid’5000 toolkit, and XtreemOS) and that can be easily extended to integrate new resource brokers or cloud systems such as Nimbus, OpenNebula, or Eucalyptus, for instance.     

脉冲防暴水炮运动参数仿真研究

研究增大脉冲防暴水炮的有效射程问题,脉冲防暴水炮是用于处置群体性骚乱事件的大型非致命武器装备,在实战中发挥了重要作用。为改善防暴水炮射程和刺激剂雾化效果,就需要对脉冲防暴水炮的运动参数进行优化设计。通过建立数学模型,然后运用FLUENT流体仿真软件进行运动仿真,最后结合Tecplot后期处理软件的分析,得出了初始压力、初始水量、初始射角等运动参数对水炮射程及雾化效果的影响。在综合各种因素的基础上选择出最佳初始压力和最佳水量,仿真效果比较有效,为设计提供了依据。     

两种坐标校正方法的精度仿真分析

坐标校正方法的恰当选取是利用纸质地图进行空间数据录入过程中的重要步骤,它严重地影响着空间数据的质量。基于地理坐标的校正法与基于投影坐标的校正法是目前普遍使用的两种坐标校正方法。该文以MapGIS软件为主要工具,对基于高斯-克吕格(Gauss-Krüger)投影的多种比例尺地图分别进行了两种不同坐标校正过程的仿真,得到了不同坐标校正方法的误差值统计特征,定量地比较了两者之间的优劣性。对测量数据处理、计算机制图及空间数据生产具有指导意义。     

A synopsis of present day practices concerning decision support systems

Selecting a decision support system that fits specific needs, both technically and financially, is a difficult task. The marketplace has been flooded with software bearing the “DSS” label. To provide a clearer picture, the article examines a number of popular DSS definitions and its development. DSS are broken into groups with similar characteristics to examine current software and applications. These groups include Personal Support Systems, DSS and Local Area Networks, DSS and Emulation, Timesharing Systems, Commercial Data Base Systems, and Integrated System. Within each group, current software and practices are reviewed. The potential buyer has the opportunity to compare DSS packages and possible applications. In addition, a list of important questions to ask when choosing DSS Software is included.     

红外成像导引头总体技术研究(二)

介绍了红外成像导引头总体技术研究内容：总体技术指标确定、稳定系统设计、目标背景射特性及大气传输特性分析、图像实时处理技术、系统控制回路优化设计、仿真技术、测试评估技术。对每项技术进行了较详细的技术分析。     

某型投物伞系统三维动态仿真的设计与实现

随着科技的发展,仿真的效果逐渐增强,仿真在各个领域的应用也日趋广泛.越来越多的军用和民用部门都希望用仿真技术来替代真实的训练或效果测试,以求最大限度地降低成本.文中主要利用OpenGL和VC技术设计并实现了某型投物伞系统在模拟环境中投放情况的仿真.首先介绍了OpenGL技术,接着重点探讨了通过几何建模、行为建模来建立三维图形、实现仿真的方法,并介绍了投放环境的绘制.最后给出了仿真效果视图,基本能显示出降落伞的投放完成情况.     

Office打印小技巧

快速打印文档 有时候，我们只是校对一下文稿，不要求太高的打印质量，所以打印的速度可以快一点，这是就可以用到word中的“草稿输出”功能了。在word中点击菜单“文件一打印”，显示“打印”对话框，接着点击左下角的“选项”按钮．在打开的打印选项窗口中把“草稿输出”项选中．再点击“确定”就可以了．草稿输出能大大提高打印的速度，缺点就是无法打印一些特殊的格式或图形（如图1）。     

Internet仿真实验的组织与实现

随着计算机网络的不断发展,学校计算机实验仍是在局域网环境下进行,使相关实验的效果受到影响。特别是计算机网络专业学生的实验,对Internet环境的依赖性更强。在真正的Internet环境下进行,受现实资源(IP地址和域名)和环境条件限制太多,成本也高。本文提出了一种Internet仿真技术,能完全仿真Internet环境,并能进行Internet资源的各项管理,在此基础上实现Internet上的服务与开发应用。