虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械工程三个一级学科．通过不同学科方向的合作、交叉，开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究，进行原始创新和集成创新．     

基于Quorum系统容错技术综述

Quorum系统是一种新型冗余拓扑的集合系统。在“冗余”设计的基础上，quorum通过交叉的结点把有效数据复制到其他quorum的结点中，增加了Quorum系统数据冗余性。当某些结点发生故障或者错误时，通过选举协议，从含有故障结点quorum的有效结点中选举出有效数据；或者采用互斥协议，从不含故障或者错误结点的有效quorum的结点中获得有效数据，系统仍能可靠运行。分析了各种Quorum肌系统的容错方式、性能比较，探讨了Quorum系统发展中需要改进的关键问题，并展望了未来的研究方向。     

虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械工程三个一级学科．通过不同学科方向的合作、交叉,开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究,进行原始创新和集成创新．     

虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械工程三个一级学科．通过不同学科方向的合作、交叉,开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究,进行原始创新和集成创新．     

虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械工程三个一级学科．通过不同学科方向的合作、交叉,开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究,进行原始创新和集成创新．     

虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械工程三个一级学科．通过不同学科方向的合作、交叉,开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究,进行原始创新和集成创新．     

虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械工程三个一级学科．通过不同学科方向的合作、交叉,开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究,进行原始创新和集成创新．     

虚拟现实技术与系统国家重点实验室简介

“虚拟现实技术与系统国家重点实验室”依托北京航空航天大学计算机科学与技术、控制科学与工程和机械1二程三个一级学科．通过不同学科方向的合作、交叉,开展虚拟现实领域的基础研究、应用基础研究和战略高技术研究,进行原始创新和集成创新．     

数据不再丢失

惠普拥有数个业界第一,包括在容错服务器领域;在企业级存储领域;在基于Windows的IA-32服务器领域;在基于Linux的IA-32服务器领域;在UNIX服务器领域;在管理软件领域;在个人电脑领域;在个人手持电脑领域和在打印和成像领域。在这众多的“第一”中,中国惠普有限公司企业系统集团企业服务器产品部销售及市场经理沈德昌表示:“惠普视‘容错服务器领域名列第一’为所有‘第一’中的‘第一’。”NonStop容错技术始源于20世纪70年代的天腾公     

基于奇偶校验的三容错数据布局研究

基于单容错编码的数据布局已经不能满足存储系统对可靠性越来越高的要求。对基于多容错编码的数据布局的研究受到了广泛的关注，并且出现了一些三容错的布局算法，如HDD1，HDD2等。但这些布局算法普遍存在冗余度较差、计算负载大等缺点。提出了一种基于三重奇偶校验的多容错数据布局算法TP-RAID(Triple Parity RAID)。该算法只需要在RAID5阵列系统中增加两个校验磁盘，通过水平、正向对角和反向对角三重奇偶校验，可容许同时发生的三个磁盘故障。该算法编码、解码简单，三重校验条纹长度相等，计算负载小，易于实现。此外，由于该算法中尽量减少了三重校验之间逻辑关联，使得该算法的小写性能比其他的三容错算法相比有了大幅度的提高。     

可信网络研究

当前孤立、单一和附加的网络安全系统已经不能满足客观需求．该文在分析可信网络的产生背景和动机的基础上,提出了可信网络的概念,揭示了其基本属性,即安全性、可生存性和可控性,阐述了它们之间的紧密联系,并讨论了可信网络研究需要解决的关键科学问题．最后,介绍了国际上与此相关的研究工作．     

Physical Safety and Cyber Security Analysis of Multi-Agent Systems: A Survey of Recent Advances

Multi-agent systems (MASs) are typically composed of multiple smart entities with independent sensing, communication, computing, and decision-making capabilities. Nowadays, MASs have a wide range of applications in smart grids, smart manufacturing, sensor networks, and intelligent transportation systems. Control of the MASs are often coordinated through information interaction among agents, which is one of the most important factors affecting coordination and cooperation performance. However, unexpected physical faults and cyber attacks on a single agent may spread to other agents via information interaction very quickly, and thus could lead to severe degradation of the whole system performance and even destruction of MASs. This paper is concerned with the safety/security analysis and synthesis of MASs arising from physical faults and cyber attacks, and our goal is to present a comprehensive survey on recent results on fault estimation, detection, diagnosis and fault-tolerant control of MASs, and cyber attack detection and secure control of MASs subject to two typical cyber attacks. Finally, the paper concludes with some potential future research topics on the security issues of MASs.      

Secure and reliable clustering in wireless sensor networks: A critical survey

In the past few years, research interest has been increased towards wireless sensor networks (WSNs) and their application in both the military and civil domains. To support scalability in WSNs and increase network lifetime, nodes are often grouped into disjoint clusters. However, secure and reliable clustering, which is critical in WSNs deployed in hostile environments, has gained modest attention so far or has been limited only to fault tolerance. In this paper, we review the state-of-the-art of clustering protocols in WSNs with special emphasis on security and reliability issues. First, we define a taxonomy of security and reliability for cluster head election and clustering in WSNs. Then, we describe and analyze the most relevant secure and reliable clustering protocols. Finally, we propose countermeasures against typical attacks and show how they improve the discussed protocols.     

Cyber security in the Smart Grid: Survey and challenges

The Smart Grid, generally referred to as the next-generation power system, is considered as a revolutionary and evolutionary regime of existing power grids. More importantly, with the integration of advanced computing and communication technologies, the Smart Grid is expected to greatly enhance efficiency and reliability of future power systems with renewable energy resources, as well as distributed intelligence and demand response. Along with the silent features of the Smart Grid, cyber security emerges to be a critical issue because millions of electronic devices are inter-connected via communication networks throughout critical power facilities, which has an immediate impact on reliability of such a widespread infrastructure. In this paper, we present a comprehensive survey of cyber security issues for the Smart Grid. Specifically, we focus on reviewing and discussing security requirements, network vulnerabilities, attack countermeasures, secure communication protocols and architectures in the Smart Grid. We aim to provide a deep understanding of security vulnerabilities and solutions in the Smart Grid and shed light on future research directions for Smart Grid security.     

Byzantine Agreement under dual failure mobile network

Networks are trending towards wireless systems that provide support for mobile computing. The Byzantine Agreement (BA) protocols used in static networks do not perform well in a dynamically changing mobile environment. Mobile commerce and related applications are necessary for wireless networks. There are numerous properties in a wireless network that play important roles. For example, the processors in a wireless network have highly mobile capabilities. Processors can immigrate into or move away from the network at any time. Although mobile technology has brought greater convenience, it is comparatively more dangerous. Wireless systems are susceptible to security flaws such as attacks by hackers. The number of allowable faulty components within the system is also decreased. To increase the number of allowable faulty components and ensure network security, a simple, secure and efficient protocol, BAM, is proposed to handle the BA problem. The fault symptoms include malicious and dormant faults. Furthermore, the proposed protocol uses the minimum number of message exchange rounds to make all healthy processors agree on a common value and can tolerate the maximum number of allowable faulty components. The proposed method will also ensure message security and increase the system's fault tolerant capability.     

移动边缘计算安全防御研究

移动边缘计算（Mobile Edge Computing,MEC）通过进一步将电信蜂窝网延伸至其他无线接入网络,可以有效地解决传统网络中回程链路负载过重、时延较长的问题。但由于 MEC 服务节点暴露在网络边缘,且计算能力、存储能力和能量受限,更易受到攻击者的青睐。在分析移动边缘计算面临的安全威胁问题基础上,针对设备安全、节点安全、网络资源及任务和迁移安全等4个不同的安全主体归纳并阐述了移动边缘计算面临的若干关键问题与挑战,总结归纳了现有的安全解决方案。最后,从动态场景下的有限资源防御模型、综合信任基础的资源部署、以用户为中心的服务可靠性保证3个方面,展望了移动边缘计算安全防御面临的开放性问题和未来的发展趋势。     

基于马尔科夫预测的多传感器故障检测与诊断机制

随着无线传感器网络应用规模的不断扩大,各类应用中传感器故障检测与诊断成为系统正常作业、安全可靠性保障的关键技术。针对多传感器系统与节点工作过程定义3种状态,基于故障检测信息建立状态转移矩阵,通过马尔科夫模型预测传感器故障信息,为故障检测与诊断提供决策依据。另外,拓展数据包信息字段包括故障类型、节点定位等,故障处理后节点转移至正常状态后将故障处理和诊断特征等信息存储到网关或者汇聚节点,为改善故障检测精度和诊断效率以及系统资源利用率提供依据。实验结果表明：所提故障检测与诊断算法与传统算法相比,具有更高的故障检测精度,更短的故障诊断时延、能够准确判断故障类型等性能。     

Fault-tolerant grid architecture and practice

Grid computing emerges as effective technologies to couple geographically dis-tributed resources and solve large-scale computational problems in wide area networks. The fault tolerance is a significant and complex issue in grid computing systems. Various techniques have been investigated to detect and correct faults in distributed computing systems. Unreliable fault detection is one of the most effective techniques. Globus as a grid middleware manages resources in a wide area network. The Globns fault detection service uses the well-known techniques basedon unreliable fault detectors to detect and report component failures. However, more powerful techniques are required to detect and correct both system-level and application-level faults in agrid system, and a convenient toolkit is also needed to maintain the consistency in the grid. Afault-tolerant grid platform (FTGP) based on an unreliable fault detector and the Globus faultdetection service is presented in this paper. The platform offers effective strategies in such threeaspects as grid key components, user tasks, and high-level applications.     

War Driving and WLAN Security Issues—Attacks, Security Design and Remedies

Mobile computing is evolving at a rapid pace with 802.11 networks; the fuzzy boundaries make it easy for intruders to intercept the radio signals. War driving was performed along highways; the resulting packet analysis is explained to show how easy some security attacks can be. An elaboration is done on a host of wireless security attacks that leads to the discussion of secure wireless network design, along with some network security simulation. The paper concludes with a list of security recommendations.     

一种安全的多源网络编码签名算法

网络编码已被证明在提高网络传输速率、减少网络拥塞、增强网络可靠性以及降低结点能耗等方面有着巨大优势,因此可被广泛用于计算机网络、无线传感器网络以及p2p系统中。但是,网络编码也面临着多方面的安全威胁,其中污染攻击是其最主要的安全威胁之一。目前,绝大部分的签名方案均只能适用于对单源网络编码中的污染攻击,无法满足普遍存在的多源网络编码的安全要求。对多源网络编码中的污染攻击进行了更深入的分析,给出了安全的多源网络编码所需要满足的条件,提出了一个安全高效的多源网络编码签名算法来预防网络中的污染攻击,该算法可以满足多源网络编码的全部安全要求。