基于DCS系统DPU的UDP数据报与TCP传输系统软件设计

为了提高DCS系统数据传输效率与可靠性,提出该系统应采用基于以低功耗、高性能的ARM控制器为主控的分散处理单元(DPU),另外在软件设计方面,要通过避免复杂的窗口算法,提高系统通讯效率.该系统软件设计在协议栈中共创建了网卡接收、TCP、UDP三个任务.TCP任务优先级最高,三者通过操作系统提供的功能,实现任务之间的切换...     

IP级网络拓扑测量技术的研究与实现

对现有的常用的两种网络拓扑测量技术进行了分析研究,实现了基于traeeroute技术的网络拓扑测量系统并用其测量了中国网络,通过与Iplane的测量结果对比评价了其可用性。首先讨论了基于SNMP协议的拓扑测量方法,并指出其优缺点。随后讨论了基于traceroute技术的拓扑测量方法,描述了基于traeeroute技术的拓扑测量系统的设计构架和关键技术。最终利用拓扑测量系统测量了中国网络拓扑,然后将其测量结果同Iplane测量的中国网络拓扑进行复杂网络特征分析。通过特征对比发现,测量系统挖掘出的拓扑呈现出更显著的非相称性、更弱的聚集和更短的距离,证明了该系统的可用性。     

GB28181标准与ONVIF协议媒体播放兼容性的研究与实现

针对ONVIF协议和GB28181标准关于媒体播放流程不一致问题,提出了一种通过RTSP代理服务器的方式来解决这一问题。论文分析了系统总体结构,媒体请求会话流程以及RTSP代理程序流程并实现。实验结果表明,RTSP代理服务器方式很好的解决了ONVIF协议和GB28181标准媒体播放会话流程不一致的问题。     

Vulnerabilities in Chen and Deng's RFID mutual authentication and privacy protection protocol

As incorporation of RFID (Radio Frequency IDentification) tags in a wide variety of applications increase, there is a need to ensure the security and privacy of the entity to which these tags are attached. Not surprisingly, this is a very active area as attested by the large number of related published research literature. Recently, the journal engineering applications of artificial intelligence published a paper by Chen and Deng (2009) where the authors propose a mutual authentication protocol for RFID. This protocol has fundamental flaws that can be readily taken advantage by a resourceful adversary. We identify and discuss these vulnerabilities and point out the characteristics of this protocol that exposes it to these vulnerabilities.     

802.1x协议在办公内部网络中的应用

本文通过介绍802.1x协议在办公内部网络中的应用,拟在帮助读者对内部网络与外部网络有更深入的认知,并提高对网络安全问题的警惕性。     

浅析IPv6邻居发现协议中无状态地址自动配置机制

在IPv6中,地址自动配置分为有状态地址自动配置和无状态地址自动配置。当站点不特别关注主机使用的确切地址,只要求该地址是惟一的并且能通过适当方式被寻路时,则适合使用无状态地址自动配置。本文针对IPv6中无状态地址自动配置机制进行简要的学习和分析。     

哥本哈根气候变化大会与中国涂料工业的发展

回顾了国际社会在应对气候变化方面的历史里程,重点介绍了哥本哈根气候大会的意义,简单介绍了我国政府应对气候变化方面的立场和主张,对于碳减排等基本概念做了介绍。最后结合我国涂料行业的实情,提出一些建议,希望能推动本行业在减少二氧化碳排放量方面做出一点贡献。     

评美国政府关于逐步削减HFC消费与生产的最新表态

就美国政府关于逐步削减HFC消费与生产的最新表态,对其背景、立场,美国政府所面临的尴尬局面及中国人该怎么办作了简短评述.     

Deep-Space Transport Protocol: A novel transport scheme for Space DTNs

The Delay-/Disruption-Tolerant Networking Architecture calls for new design principles that will govern data transmission and retransmission scheduling over challenged environments. In that context, novel routing, transport and application layer algorithms have to be established in order to achieve efficient and reliable communication between DTN-nodes.In this study, we focus on the evolution of the terrestrial Internet into the Interplanetary or Space Internet and propose adoption of the Deep-Space Transport Protocol (DS-TP) as the transport layer scheme of choice for the space networking protocol stack. We present DS-TP’s basic design principles and we evaluate its performance both theoretically and experimentally. We verify that practice conforms with theory and observe great performance boost, in terms of file delivery time between DTN-nodes, in case of DS-TP. In particular, the gain of DS-TP against conventional proposals for deep-space communications increases with the link error rate; under conditions DS-TP can improve the performance of the transport layer protocol by a factor of two (i.e., DS-TP can become two times faster than conventional protocols).     

To Intervene or not to Intervene: The Dilemma of Management by Exception

Future air traffic management architectures propose to give aircraft more flight path autonomy and turn the air traffic controller into a manager of exceptions. This article reports on one experiment in a series of studies that empirically explored the cognitive work underlying management by exception in air traffic control. Active practitioners (controllers, pilots, dispatchers) were prepared on the rules of the envisioned system and presented with a series of future incidents, each of which they were required to jointly resolve. Management by exception turns out to trap human controllers in a double bind, where intervening early seems appealing but is difficult to justify (airspace throughput) and carry out (controller workload problems). Late interventions are just as difficult, since controllers will have to take over in the middle of a potentially challenging or deteriorating situation. Computerised decision support that flags exceptions migrates the decision criterion into a device, creating a threshold crossing that is typically set either too early or too late. This article lays out the intertwined trade-offs and dilemmas for the exception manager, and makes recommendations for cooperative human–machine architectures in future air traffic management.