基于精确时间协议的HL-2M装置定时同步网络研究

基于HL-2M装置对时序精度的要求,参考ITER的设计方案,设计了基于精确时间协议(PTP)的HL-2M分布式时间通讯网络,使HL-2M装置的时钟同步和事件触发的精度从微秒级提高到亚微秒级,最终优于100ns.     

Molecularly engineered graphene surfaces for sensing applications: A review

Graphene is scientifically and commercially important because of its unique molecular structure which is monoatomic in thickness, rigorously two-dimensional and highly conjugated. Consequently, graphene exhibits exceptional electrical, optical, thermal and mechanical properties. Herein, we critically discuss the surface modification of graphene, the specific advantages that graphene-based materials can provide over other materials in sensor research and their related chemical and electrochemical properties. Furthermore, we describe the latest developments in the use of these materials for sensing technology, including chemical sensors and biosensors and their applications in security, environmental safety and diseases detection and diagnosis.     

基于网格的一种安全组播密钥分配策略

在网格中,组播是实现大规模信息资源共享的一种重要方式,然而,如何保障组播的安全性是一个十分复杂的问题.本文将以集中控制和分布式管理所采用的密钥管理策略为基础,在遵循网格组播机制的前提下,考虑成员动态变化因素,提出了分层方法、成员发现协议、分簇协议和密钥分配策略,从而形成了一种基于网格的安全组播密钥分配策略.仿真实验结果表明此密钥分配策略具有良好的可行性和有效性.     

基于截短ARQ协议的协作分集系统吞吐量研究

研究协作分集通信系统的跨层设计使系统吞吐量最大化.首先推导基于截短ARQ协议的协作分集和两跳系统的吞吐量理论表达式,揭示数据包长度和调制方式对系统吞吐量的影响,在此基础上用自适应技术优化系统性能,采用连续二维优化求出了吞吐量的最大值,进而提出了实用的二维离散吞吐量优化算法,该算法的优化结果与吞吐量最大值相差很小,最后提出了计算量更小的一维离散优化算法,且其吞吐量性能损失也很小.     

一种改进的多跳分组无线网路由协议

对于多跳分组无线网来说,路由协议非常重要.而传统的主动式路由、按需路由和混合路由由于自身的缺陷,都不能保证多跳分组无线网传输的可靠性.为了适应网络拓扑不断变化的客观环境,提高数据通信的可靠性,提出了一种相邻矩阵路由协议,它克服了传统路由协议的缺点,大大提高了多跳分组无线网的链路性能.     

一种基于TDMA的Ad Hoc网络的虚电路建立协议

为了实现网络中端到端的可靠传输,在基于TDMA的Ad Hoc网络里引入一种虚电路建立协议.该协议采用分布式的资源预约方式建立虚电路,对于网络拓扑变化所引起的链路故障,能够及时发现和处理,且具有相对较小的开销和较高的可靠性,比较适合Ad Hoc网络.     

IEEE 802.22标准的MAC层协议分析

介绍了IEEE 802.22(WRAN,无线区域网)标准提出的背景和进展情况,对IEEE 802.22草案中的MAC(媒体接入控制)层技术进行了描述,介绍并分析了WRAN系统对授权用户的检测和WRAN系统的自共存机制等方面的内容,说明了WRAN未来的研究方向并展望了其市场应用前景.     

Free-Space QKD with Modulating Retroreflectors Based on the B92 Protocol

Free-space quantum key distribution (QKD) has attracted considerable attention due to its lower channel loss and link flexibility. It allows two participants share theoretical unconditional secure keys, and can potentially be applied to air-to-ground quantum communication to establish a global quantum network. Free-space QKD using modulating retro-reflectors (MRR-QKD) significantly reduces the pointing requirement and simplifies the structure of the mobile terminal, therefore making it suitable for lightweight aircraft such as unmanned aerial vehicle and Cubesat, etc. Based on intensity modulation of two non-orthogonal states and the B92 protocol, we proposed a scheme to improve the previous work (Optics Express 2018, 26, 11331). Our scheme simplifies the optical structure and shows more robustness in equipment imperfection. The analysis and simulation show that the number of multiple quantum well modulators needed in our scheme decreases from eight to three with similar performance. Additionally, while the previous scheme cannot work due to low modulator extinction ratio or high optical misalignment, our scheme can still operate.     

MANET路由协议的最新发展

由于移动Ad hoc网络(MANET)自身的特殊性,其路由协议的设计与传统固定网络有很大不同。本文在MANET路由协议的设计原则的基础上,分析了几种典型的MANET路由协议的特点,并对MANET路由协议未来的发展方向作出了展望。     

数字移动通信系统中认证协议的设计与分析

该文针对数字移动通信系统的背景和需求, 基于公钥密码体制设计了一个端端密钥分发协议,基于对称密码体制设计了一个身份认证协议,并利用Spi演算对身份认证协议进行了分析,证明了其安全性。