一种高能效低时延的LLN路由修复算法

由于低功耗有损网络(LLN)中无线链路的不稳定性和有损性,外部环境的干扰极易导致网络出现故障,从而严重影响网络性能,而LLN网络中现有路由修复算法存在控制开销冗余和修复时延较大等问题。为此,提出了一种高能效低时延的LLN路由修复算法(EELDR-RPL)。该算法通过采用“零额外控制开销通告链路故障及邻居节点信息”机制,使得链路故障节点的子节点能够及时获知链路故障以及链路故障节点的邻居情况;通过采用“自适应调整节点网络深度值”机制,使得链路故障节点能够快速地重新接入网络;通过采用“链路故障节点子节点自适应切换”机制,能够达到优化网络拓扑的目的。仿真结果表明,与现有路由修复算法相比,EELDR-RPL算法能够有效地降低路由修复时延和减少控制开销。     

无线多媒体传感器网络中一种改进路由算法

随着网络负载增加，经典的TPGF（Two-Phase geographic Greedy Forwarding）算法难以找到节点分离路径，会导致网络吞吐量、投递率以及端到端时延性能下降。此外，当网络拓扑变动不大时，TPGF中每条路径所包含节点要消耗比其他节点更多的能量，会导致其过快死亡，从而影响网络性能。为此，将联合网络编码技术引入TPGF，提出一种编码与能量感知的TPGF路由算法（NE-TPGF）。该算法综合考虑节点的地理位置、编码机会、剩余能量等因素，同时利用联合网络编码技术进一步扩展编码结构，充分利用网络编码优势来建立相对最优的传输路径。仿真结果表明，NE-TPGF能够增加编码机会，提高网络吞吐量和投递率，降低端到端时延，并且还有利于减少和平衡节点的能量消耗。     

中继蜂窝网中基于负载均衡的中继节点选择算法

提出了一种中继蜂窝网络的基于负载均衡的中继节点选择策略(Load Balancing Rela y Selection,LB-RS)。根据每个用户的具体信道状况以及中继节点服务的用户数目,LB-RS 以分布式的方式为每个用户选择最优的中继节点。仿真结果表明,与基于单一物理层参数的 中继节点选择算法相比,所提出的中继选择算法综合考虑了物理层的信道状况以及MAC层 的资源与用户状况,有效地利用中继节点选择来实现小区内的负载均衡,获得了吞吐量性能 与用户公平性之间的折衷。     

太阳能无线传感器网络节点传输功率策略优化

针对配备太阳能采集设备的无线传感器网络节点，以如何合理使用采集到的能量使得时间期限内点对点传输的数据量最大为优化目的，结合必要的约束条件（能量获取电池只有有限的能量存储能力以及能量因果关系），建立了数据传输的能量通道优化模型，通过能量通道策略优化算法得到了最优传输功率策略。与当前普遍使用的能量即到即用方法进行了性能对比，仿真发现系统累积传输了更多的数据量，性能提升明显。在此基础上，考虑了实际太阳能获取量与预测值的偏差，提出了改进的能量通道算法，使得其更加适应于实际场景中。     

一种适用于异步无线传感器网络的机会路由机制

无线传感器网络通常使用低占空比的异步睡眠调度来降低节点能耗。由于发送节点在接收节点醒来后才能向其发送数据,这将引入额外的等待时延。在最近的一些任播路由机制中,发送节点动态地选择最先醒来的候选节点转发数据,以最小化等待时延。但是,由于从最先醒来的候选节点到基站的时延可能并不低,任播路由机制并不一定能最小化端到端总时延。为此,提出了一种适用于异步无线传感器网络的机会路由机制,将路由决策建模为强马尔科夫过程,并根据最优停止理论推导出该过程一种简化的停止规则。仿真结果表明,节点到基站的最大端到端时延仅为基于地理位置的机会路由的68.5%.     

无线传感器网络能量高效混合MAC算法

针对无线传感器网络MAC协议中存在的能耗问题,提出了能量高 效的无线传感器网络混合MAC（EEH-MAC）算法,采用基于TDMA机制的时槽系数动态调整簇内 节点的时槽大小来降低数据的传输时延;同时,对部分不需要数据传输的节点不分配时槽来 减少能耗;按簇内节点剩余能量系数形成时槽分配顺序来减少状态转换的能耗;在簇头之间 采用CSMA/CA机制的随机分配策略进行通信。仿真结果表明,EEH-MAC协议能有效减少能耗并 延长网络生命周期。     

一种基于UAV的无人海岛监控网络数据收集策略

针对传统的最小跳路由无线传感器网络（WSN）在数据汇聚上较高的能量开销问题，提出了一种基于无人机(UAV)数据收集的动态分簇算法,其主要思想是利用节点剩余能量来确定那些节点可以当选簇首,同时利用节点坐标位置和设定地分簇半径来划分簇的大小。该算法的优势是能最大程度地均衡每个传感器节点的能量，使整体的节点剩余的能量维持在同一水平。为了提高数据收集的效率，采用蚁群算法规划了无人机数据收集的最短路径。仿真结果表明，与相同的分簇算法下传统的最小跳路由无线传感器网络相比，所提出的基于无人机的无线传感器网络（UAV-WSN）在能量利用率和生命周期方面分别提升了15%和25%，并且以上两种网络的能量利用率高达70%。     

面向ICN的非合作博弈优化缓存策略

针对信息中心网络（Information-Centric Network，ICN）的缓存分布问题，提出了一种基于非合作博弈算法(Non-cooperative Game)的优化缓存策略。算法将ICN网络建模成复杂网络，采用非合作博弈框架，兼顾用户服务质量（Quality of Service,QoS）的情况下，综合缓存节点距离、能效和流行度对网络中每个节点构建相应的效用函数，采用分布式迭代算法解出非合作博弈的纳什均衡解，得到全局最优的效用函数值，获取最佳的缓存分配结果。仿真结果表明，在用户请求次数和请求内容流行度不断增加的情况下，使用非合作博弈算法可以减少网络整体能耗，提高平均缓存命中率，减少平均响应跳数。     

MIL-STD 188-220C协议中的NAD算法

M IL-STD 188-220C是军用分组无线电C4I系统之间的互操作标准。协议的流量控制采用5种不同的网络访问延迟(Network Access Delay,NAD)算法实现。为解决不同NAD算法之间如何选择的问题,基于战术互联网应用环境,采用了网络仿真的方法,对协议进行了分析比较,在信道吞吐量、端到端时延、对信息优先级的支持、节点公平性和实现复杂性等方面,得出了不同NAD算法的性能和特点。这些结论对于协议的应用和改进都有一定的参考意义。     

基于IEEE802.11 DCF的链路预先修复AODV路由协议

基于无线自组织网络中普遍使用的底层通信协议IEEE802.11 DCF,针对广泛应用于无线自组织网络中的路由协议(AODV),提出了一种链路预先修复算法。该算法首先推算了DCF协议中的不稳定传输范围,然后通过MAC层与路由层的跨层协作,在下一跳节点移动在不稳定传输范围时就事先采取相应的路由修复措施。相对于AODV中采用节点周期性地发送HELLO消息来监测邻居节点变化的方法,该算法更为高效及时。仿真结果表明,该算法能够有效的减小端到端时延,保障了投递率。     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.     

Challenge and Opportunity Go Hand in Hand——What Global Economic Agitation Brings to the China's Economy?

Domino effects of the global finance agitation As the origin of the subprime crisis,US financial institutions lost USS45 billion last year,accounted for over half of the total US,EU & Japan loss.Since January 15th,Chtigroup released its financial statement of the 4th quarter,showing a net deficit of USS9.83 billion,which marked the hisoric high of its quarterly deficit.     

Sinosteel：Extraordinary Moves in Industry Chess

Among the Fortune 500 firms,more and more images from China emerge out.On the 2008 list,Sinosteel Corporation,a landmark group of China industries quietly squeezes into the candidate line.As the largest steel service ＆ trade enterprise,its sales reached at RMB 111.24 billion,with a year-on-year increase of 83.03 percent,and the profit grew by 180.03 percent.On the Sinosteel 2008 Work Meeting,the president Huang Tianwen uttered,＂In the coming year,we will work for US$20 billion sales,and look forward to getting a position in Fortune 500 firms for ourselves.＂     

Walk Through Unusual Five Years—— An Exhibitor＇s Canton Fair Course

When the 103rd Canton Fair is approaching, an old friend of Canton Fair, Li Ying from Jiangsu prov-ince recollected his past five years＇ experiences to the grand trade meeting. Each year is special, with some unforgettable memories colored by the year.     

Universal Coverage, Pinpoint Illustration and Profound Impact HTC 2008 Intermedia Recommendation and Introduction Meeting

Holding 88 percent of train media resources across China, based on "Time Cube", on the 2008 Intermedia Recommendation and Introduction Meeting on December 19, 2007, HTC announced its high-profile strategy of tour marketing and tapping the immeasurable potentials on the train. Meanwhile, HTC officially launched its brand new product Olympic Train on the meeting, providing a fabulous platform for all the brands that are prepared to do a smart marketing on the occasion of 2008 Olympic Games.     

Market presence in China strengthened Network growth and Dual-Chinese-Hub Strategy More frequet Flyer Benefit——Air China and shanhai Airlines Join Star Alliance

In the end of 2007, Air China Limited (hereinafter "Air China") and Shanghai Airlines, formally joined Star Alliance at a ceremony held in the new Terminal Three at Beijing Capital International Airport. With the addition of the two Chinese airlines, Star Alliance now has 19 member carriers operating 17,000 daily flights to 897 destinations in 160 countries.     

China''''s Stock Market Wave

The annual meeting of the World Economy Forum was held in Davos,a little town in Switzerland,on January 23rd to the 27th this year,with the theme"the Power fo Collaborative Innovation",over 2500 celebrates from ture political and cconomic circles of more than 80 countries and challengred logether to talk about the future of the global economy in 2008,A Forum for the problems and challenges that face whole world,some of the keywords which drew attention during the event were:the U.S.subprime mortgage crisis,soaring energy prices,the economic slowdown in the U.S.ermerging economic bodies,authority funds and the general unpredictable nature of the global economy.     

Trade Promotion from Neighborhood

If you are considering to trade with companies in Japan or expanding your .business to Japan, we are ready to help from the very beginning.＂ You will find this greeting at the first sight on the Chinese website of Japan External Trade Organization （JETRO）. JETRO has committed itself in delivering highly efficient and quality services to meet the demand of internal and external customs including Japanese companies, hence winning a good reputation in the international trade arena. In recent years, with its priority in advancing business cooperation in South and East Asia, JETRO has made great achievement in promoting trade between China and Japan. Therefore, China＇s Foreign Trade interviewed Mr. Yoichi Maine, Deputy Director General of JETRO BEIJING.     

Auto Parts Market Potential Coming into Surface

Looking at the increasingly fierce competition in the world auto market. global automobile manufacturing industry, taking Europe, the U.S. and Japan as representatives, is gradually forming a new type of relationship, mutual cooperation between whole vehicle and parts manufacturers. We can clearly see that auto parts manufacturers have become independent from the whole vehicle manufacturing companies, which means that the former structure of auto industry has greatly changed, and a new relationship,     

Jean-Pierre Duprieu： Willing to Be A Legate of Sino-French Business

Estaing, former French president, Valery Giscard d＇Estaing attended Sino-French Economic Seminar held in Shanghai in early April and said that the world center has shifted from the west to the east with many European and US companies entering into Asia, and China has the ability to play an important role in the world stage. Estaing, naming himself＂French Confucian＂, then said in Chinese that a cook-group includes 10 people in ancient Chinese soldier system and the cook is in charge of cooking for them. And people who belong to the same cook are actually ＂Partners＂.