Stochastic Modeling of Database Backup Policy for a Computer System

As the computer system has developed much in this highly information-oriented society, database security has become a very important problem and its backup strategies need to be made more efficiently and safety. The image copy method has been used as the most simple and dependable recovery mechanism for media failure. However, this method spends high overhead costs for massive data transmission and much processing time in the normal operation of the database. To cover such weak points, incremental and full backup methods are adopted before updated trucks reach a predetermined level. Moreover, when the number of full backup files exceeded a predetermined level, we stop incremental and full backups and switch it to the image copy. This paper applies cumulative damage model to backup of files in a database system, by putting damage shock by update, failure shock by database failure and damage by dumped files, and considers the tradeoff among overhead costs of image copy and incremental, full backup methods, and discusses analytically an optimal policy for the image copy backup interval. Finally, numerical examples are given in the case of Poisson process and exponential distributions.

Efficient Multi-Resolution Compression Algorithm for Disk-Based Backup and Recovery

In this paper, we deal with the problem of improving backup and recovery performance by compressing redundancies in large disk-based backup system. We analyze some general compression algorithms; evaluate their scalability and applicability. We investigate the distribution features of the redundant data in whole system range, and propose a multi-resolution distributed compression algorithm which can discern duplicated data at granularity of file level, block level or byte level to reduce the redundancy in backup environment. In order to accelerate recovery, we propose a synthetic backup solution which stores data in a recovery-oriented way and can compose the final data in back-end backup server. Experiments show that this algorithm can greatly reduce bandwidth consumption, save storage cost, and shorten the backup and recovery time. We implement these technologies in our product, called H-info backup system, which is capable of achieving over 10x compression ratio in both network utilization and data storage during backup.

Reliability Modeling of Phased Mission System with Phase Backup by Stochastic Petri Net

This paper presents a modeling method by stochastic Petri net for reliability analysis of phased mission system( PMS) with phase backup. The model consisting of petri nets,depicts the system behaviors of unit level,system logic level and phase level. Guard functions of petri nets are used to avoid modeling complexity and make the model flexible to different reliability logical structures. It was shown that the time redundancy within phase and from phase backup for PMS can both be described by use of the proposed model.

Fault Detection Based on Hierarchical Cluster Analysis in Wide Area Backup Protection System

In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated quickly and defined exactly. In our study, global information will be introduced into the backup protection system. By analyzing and computing real-time PMU measurements, basing on cluster analysis theory, we are using mainly hierarchical cluster analysis to search after the statistical laws of electrical quantities' marked changes. Then we carry out fast and exact detection of fault components and fault sections, and finally accomplish fault isolation. The facts show that the fault detection of fault component (fault section) can be performed successfully by hierarchical cluster analysis and calculation. The results of hierarchical cluster analysis are accurate and reliable, and the dendrograms of hierarchical cluster analysis are in intuition.

Wireless Backup System of Meteorological Data Transmission

By using wireless communication technology, when wired network of grassroots station is failure, wireless backup system of meteorological data transmission can automatically switch, and transmit the data at the station with line fault to the destination by short message way. The system has simple operation and low operation cost, and transmission fault of real-time meteorological data due to line problem at the station can be effectively decreased. At present, the system has been tested successfully and put into business operation.

英华达全面部署Symantec Backup Exec System Recovery（前Symantec LiveState Recovery）取代物理备份环境并节省软硬件投资达千万，同步提升系统可用性与稳定度

成立迄今只有六年的英华达公司，以惊人的成长速度跻身高科技大厂之列。2005年更创下营收突破千亿新台币大关的里程碑，英华达坚持的用户导向品牌营销（COBM）与高效整合设计代工（IDOM）双经营模式，更成功地反应在OKWAP自有品牌手机与iPod代工业务，形成互补互利的典范。

Performance Analysis of Cell Loss Probability Based on ATM Self-healing Multi-section-backup VP Scheme

Based on ATM Multi section backup VP self healing scheme, analysis of cell loss probability under finite buffer is made by use of queue system method. Optimal buffer size can be fixed on.

Rolling-contact-fatigue behavior in backup roll of 5% Cr forged steel

With a focus on the backup roll, a rolling-contact-fatigue experiment was performed on samples of 5% Cr forged steel. The P-S-N fatigue curves were determined and the fatigue strength was calculated. The emergence of cracks on the test-sample surfaces was observed at different fatigue cycles. A micro-hardness tester was used to measure the hardness of the subsurface fatigue layer. The microstructures were analyzed at various magnifications with an optical microscope, scanning electron microscope, and transmission electron microscope. Based on these tests, the rolling-contact-fatigue mechanism of the large forged steel backup roll was also considered. The results showed that the contact-fatigue strength of the tested backup roll steel was 1 249 MPa;the surface fatigue crack lengthened continuously as the number of cycles increased and followed an S-shaped curve; the subsurface fatigue hardness reached its highest value at about 90 （HV） increment from the matrix hardness of 540 （HV） in the backup roll; the subsurface martensite/bainite microstructure was crushed and the dislocation density was greatly increased. Under alternating contact stresses,the surface/subsurface material was damaged and exhibited many microdefects. At the least, the surface fatigue layer on backup rolls should be fully removed before the microcracks enter a period of rapid propagation.

基于智能手机平台的Backup System研究与实现

随着电子信息技术的迅猛发展,智能手机正在越来越多地进入人们的生活中,在不久的将来它将成为现代社会办公、商务及家用必不可少的工具。

保护你的个人邮箱——Backup Exec for Windows Server的解决方案

随着企业信息化程度的不断提高，电子邮件系统在信息平台之中的作用和影响力已渐渐超过数据库系统。为了保证邮件系统的持续运转，人们想了许多办法，就Microsoft Exchange Server系统而言，微软提供的邮件保护技术是有限的。很多时候并不能满足用户多种多样的需求。本文介绍了两种第三方个人邮箱保护技术。对Exchange服务器自身的保护手段是一个很好的补充和完善。

BrightStor ARCserve Backup for Linux

BrightStor ARCserve Backup for Linux将BrightStor ARCserve数据保护技术移植到Linux操作系统中，Linux环境提供了可靠的本机数据保护解决方案。

产品之二：VERITAS Backup Exec9．1 for Windows Server

VERITAS Backup Exec9.1 for Windows Servers是先进的Windows数据保护解决方案,能为Microsoft Windows服务器环境提供通过Microsoft认证的,全面的、经济的、高效的保护。它提供基于Web的管理控制台和直观的类似浏览器的图形用户界面，加上使用方便的向导功能，适用于任何水平的用户和任何规模网络的数据保护和恢复。另外。

Distributed Stochastic Scheduling of Massive Backup Batteries in Cellular Networks for Operational Reserve and Frequency Support Ancillary Services

Base station(BS)backup batteries(BSBBs),with their dispatchable capacity,are potential demand-side resources for future power systems.To enhance the power supply reliability and post-contingency frequency security of power systems,we propose a two-stage stochastic unit commitment(UC)model incorporating operational reserve and post-contingency frequency support provisions from massive BSBBs in cellular networks,in which the minimum backup energy demand is considered to ensure BS power supply reliability.The energy,operational reserve,and frequency support ancillary services are co-optimized to handle the power balance and post-contingency frequency security in both forecasted and stochastic variable renewable energy(VRE)scenarios.Furthermore,we propose a dedicated and scalable distributed optimization framework to enable autonomous optimizations for both dispatching center(DC)and BSBBs.The BS model parameters are stored and processed locally,while only the values of BS decision variables are required to upload to DC under the proposed distributed optimization framework,which safeguards BS privacy effectively.Case studies on a modified IEEE 14-bus system demonstrate the effectiveness of the proposed method in promoting VRE accommodation,ensuring post-contingency frequency security,enhancing operational economics,and fully utilizing BSBBs'energy and power capacity.Besides,the proposed distributed optimization framework has been validated to converge to a feasible solution with near-optimal performance within limited iterations.Additionally,numerical results on the Guangdong 500 kV provincial power system in China verify the scalability and practicality of the proposed distributed optimization framework.

Inverse-time Backup Protection Based on Unified Characteristic Equation for Distribution Networks with High Proportion of Distributed Generations

The setting work of backup protection using steady-state current is tedious,and mismatches occasionally occur due to the increased proportion of distributed generations(DGs)connected to the power grid.Thus,there is a practical need to study a backup protection technology that does not require step-by-step setting and can be adaptively coordinated.This paper proposes an action sequence adaptive to fault positions that uses only positive sequence fault component(PSFC)voltage.Considering the influence of DGs,the unified time dial setting can be obtained by selecting specific points.The protection performance is improved by using the adjacent upstream and downstream protections to meet the coordination time interval in the case of metallic faults at the near-and far-ends of the line.Finally,the expression and implementation scheme for inverse-time backup protection(ITBP)based on the unified characteristic equation is given.Simulation results show that this scheme can adapt to DG penetration scenarios and can realize the adaptive coordination of multi-level relays.

《勇者的后盾》——Analysis of the Back-Up Forces behind Scarlett in Gone with the Wind(英文)

The protagonist, Scarlett, in the book Gone with the Wind, impresses people throughout the world, not only because of her beautiful appearance, but also her brave and strong spirit. However, everyone has his weak points, and she is not an exception. So it's sure that she needs some backup forces to support her to get through the tough days. This thesis tries to put forward Scarlett's strong backup forces, which help her pull through the tough life and finally become a real brave person who could face the rest life strongly and fearlessly all by herself.

基于Symantec Backup Exec实现的湖北国土资源数据中心备份系统

本文深入探讨了有关数据备份中离线数据存储、备份策略规划、ORACLE数据库备份特性等技术专题,同时较详细地介绍了Symantec Backup Exec备份软件的服务组件和工作原理,并基于该软件介绍了如何构建湖北国土资源数据中心备份系统的具体实现过程。

Vista数据保护五大工具 Windows Backup and Restore Center

有没有想过即使什么也不做。磁盘上的数据也能得到保护？Windows Vista彻底更新了早期操作系统中的备份特性。取代以全新的备份和还原中心——它能够让你即使从未进行过备份，也可以对删除过的文件进行恢复。而这项梦寐以求的功能，也仅仅只是它五大工具之一，我不得不承认，有了这个全能的备份和还原中心。我比以往任何时候都更加期待把Vista部署到用户的机器上……

BakBone发布NetVault Backup8．5

近日，BakBone在北京发布其旗舰产品NetVault Backup 8．5版本以及提供了基于磁盘备份和重复数据删除选项的NetVault SmartDisk。NetVault SmartDisk是基于BakBone最近发布的开放数据保护平台的第一款产品。BakBone市场副总裁Jeff Drescher表示：“我们对未来的规划是：BakBone开放数据保护平台利用同一个重复数据删除方案帮助用户整合他们已有的数据保护方案，允许用户存储来自其他数据保护方案提供商的数据并对其进行重复数据删除，从而降低花费并为用户提供更具灵活性的选择。”

An Efficient Real-Time Fault-Tolerant Scheduling Algorithm Based on Multiprocessor Systems

In the context of real-time fault-tolerant scheduling in multiprocessor systems, Primary-backup scheme plays an important role. A backup copy is always preferred to be executed as passive backup copy whenever possible because it can take the advantages of backup copy de-allocation technique and overloading technique to improve schedulability. In this paper, we propose a novel efficient fault-tolerant ratemonotonic best-fit algorithm efficient fault-tolerant rate-monotonic best-fit （ERMBF） based on multiprocessors systems to enhance the schedulability. Unlike existing scheduling algorithms that start scheduling tasks with only one processor. ERMBF pre-allocates a certain amount of processors before starting scheduling tasks, which enlarge the searching spaces for tasks. Besides, when a new processor is allocated, we reassign the task copies that have already been assigned to the existing processors in order to find a superior tasks assignment configuration. These two strategies are all aiming at making as many backup copies as possible to be executed as passive status. As a result, ERMBF can use fewer processors to schedule a set of tasks without losing real-time and fault-tolerant capabilities of the system. Simulation results reveal that ERMBF significantly improves the schedulability over existing, comparable algorithms in literature.