移动Ad Hoc网络中的负载均衡路由算法

移动Ad Hoe网络(MANET)中的路由算法应尽量使网络负载均衡，不均衡不仅导致正在通信的路由由于过度拥塞而引起数据包延时过大、吞吐量下降，而且会使拥塞节点的能量提前耗尽，从而加剧网络拓扑结构的变化及节点之间的不公平性。本文对目前提出的一些负载均衡路由算法进行了简要比较和分析，在此基础上，指出了目前负载均衡路由算法中存在的一些问题，并提出了一个实现负载均衡路由算法的一般模型。基于该模型，文中提出了一种简单的负载均衡路由算法。仿真结果表明，负载均衡路由算法比未考虑负载均衡的路由算法具有更高的数据包投递率和更低的数据包传输延时。     

无线传感器网络在农田数据监测中的应用研究——基于蚁群路由算法

采用一种优化信息素的蚁群路由算法,解决了无线传感器网络在农田数据监测中的数据传输路径问题。改进的蚁群路由算法综合考虑了传感器节点造价高昂、节点能量补充困难、信号强度易受障碍物影响以及传感器网络在农田中的应用特点等问题,在时间复杂度不变的情况下,延长了无线传感器网络的生命周期。通过matlab仿真证明:与基本蚁群路由算法相比较,采用改进的蚁群路由算法所找到的路径,具有"热路径"长度更短,无线传感器网络能耗更加均衡的优点。     

移动Ad hoc网络中两种构造最小连通支配集算法分析

移动自组网中节点移动是网络快速变化的主要原因。快速变化的网络拓扑给移动自组网,尤其是路由设计带来了巨大挑战。基于最小连通支配集算法是一种有效的分层路由算法,它将路由搜索集中在连通支配集内。详细分析了两种具有代表性的连通支配集算法,分别指出它们的不足之处,并进行了初步验证。     

一种基于信号强度的OLSR路由协议改进算法

借助接收分组时测得的信号强度,提出OLSR-PSSA(Pre-rerouting and Signal Strength A-ware OLSR)改进协议。为了建立和维护生存时间更长、链路更加健壮的路由,并加入预切换路由机制,来适应节点的移动和网络拓扑结构的频繁变化。OPNET仿真结果显示,与传统OLSR协议相比,OLSR-PSSA改进协议提升了传输成功率,增加了网络吞吐量。     

移动Ad Hoc网络中TCP性能的分析和改进

分别采用静态链状拓扑和动态网络拓扑,通过仿真分析和比较了不同TCP版本在移动AdHoc网络中的性能。文中还提出了一种改进的选择性应答算法(SSACK),以解决移动AdHoc网络中由于高丢包率和路由重建引起的TCP接收窗的"缺口(gap)"问题。仿真结果显示,改进的SSACK算法在一定程度上改善了移动AdHoc网络中的TCP性能。     

基于阈值判断的动态源路由协议算法优化设计

针对移动自组织网动态源路由协议（DSR）中旧路径中断至新路径建立期间存在的丢包和端到端时延问题,设计了一种基于阈值判断的路由发现和维护算法,以优化路由协议性能。该方法首先定义节点电池能量和节点接收信号能量双阈值等级,分别用于衡量节点和既存链路状态;然后修改路由发现和路由维护算法,使动态源路由具备阈值判断功能。分别对增强型动态源路由协议（EDSR）包传递率和端到端时延等性能随节点数目和移动速度等参数的变化规律进行了软件仿真。实验结果表明,节点数目超过150或者速度小于10 m/s时,EDSR端到端时延和包传递率优于DSR,其他性能基本相当,因此EDSR协议性能得到明显改善,为低速大规模移动自组网路由协议提供了重要参考。     

能量采集型无线传感器网络的高能效路由算法

在能量采集型无线传感器网络中,虽然有能量吸收,但是因能量依然非常珍贵,如何优化路由协议,提高能量利用率,延长网络寿命仍然是值得研究的问题。为求解高能效的路由,提出了一种采用遗传算法的高能效路由算法,建立考虑节点的吸收能量、剩余能量、消耗能量和浪费能量的适应函数,用遗传算法寻找全局最优路径。将该适应函数与3种其他适应函数作对比,其他3种适应函数分别为只考虑路径能耗最小的适应函数,考虑路径能耗与路径上节点的吸收能量、剩余能量的适应函数以及考虑路径能耗与网络中所有节点的浪费能量的适应函数。采用遗传算法解出4种路由,通过仿真分析可知,所提出的路由算法能量利用效率最高。     

基于灰狼算法的无线网络组播路由优化

针对无线网络中资源受限的组播路由问题,考虑网络节点的节点度限制和网络链路的带宽约束,以最小化组播路由开销为目标,提出了一种二进制编码方式的基于灰狼优化算法的组播路由策略。在给定的网络拓扑下,基于灰狼优化算法的组播路由策略可以迅速找到一棵包含源和目的节点的最小开销组播树。仿真结果表明,相比于遗传算法,所提出的基于灰狼优化算法的组播路由策略可以得到一棵开销更小的组播树,并且在相同的时间复杂下具有更强的算法稳定性。     

基于攻击策略的复杂网络拓扑结构优化模型

针对不考虑攻击策略时以自然连通度作为复杂网络抗毁性测度存在的缺陷,用节点的改进总连通度作为目标函数建立了基于按度攻击策略的复杂网络拓扑结构优化模型,并运用收敛速度较快的自适应局部增强微分进化算法（ADMPDE）对复杂网络的拓扑结构优化进行仿真分析。仿真结果验证了该模型的合理性和算法的适用性,优化后的复杂网络的度大节点比例提高了32%,其抗毁性得到明显改进,并得到一些有意义的结论。相关内容可为该领域的进一步研究提供有价值的参考。     

空中骨干网络路由协议改进设计

空中骨干网络由多个空中平台通过无线连接构成,并能够为各类中小型空中平台提供 网络服务。空中骨干节点具有动态性,造成骨干网拓扑结构具有可变性,采用商用路 由协议将会造成网络开销过大、无法维护正确的网络拓扑信息等问题。通过对空中骨干网络 特点进行分析,在商用主动式路由算法的基础上进行跨层设计,并优化泛洪机制,实现了网 络 开销随着链路状态进行动态变化,利用较小的网络开销来维护准确网络拓扑结构。仿真结果 表明,改进的路由协议基本满足空中骨干网的要求。     

Public Financial Expenditure——A Reflection of the Livelihood Improvement

In recent years.China's public finance put social construction high on the agenda and attaches more importance on livelihood insurance and improvement.The 2003-2007 public financial expenditure reflects a fact that the government isputting more emphasis on livelihood andissues concerning the people.     

Voices from the MPC and CPPCC

"Crucial for economic growth.energy utilization has its role in all economic sectors and every aspect of people's daily life.Now we are in dire need of a new profession,namely energy manager.We not only need to have passion and responsibility,but also a scientific approach to conserve energy and cut emissions.APpropriate legislation should be in place.and a special profession should be introduced to ensure the implementation of these laws and regulations."     

Slowdown Trade Surplus Growth

According to Ma Kai＇s economic planning report submitted to the NPC session on March 5th,（Ma Kai is the Minister in charge of the National Development and Reform Commission）,the government has listed the slowdown in trade surplus growth and the steady expansion of external investment as major tasks for 2008.     

Ouyang Riping： A Hero Besides Entrepreneur

A bout fifty years ago. a baby＇s cry broke the sky of quietness, in a small and beautiful town of Hunan province, which surroundcd by green hills and clear water. Though his .birth brought his family great happiness and hope just as any new life, nobody knew that the little boy would get great achievement when he grow up. even start his business oversea, and earn international honor. Let＇s share with you the entrepreneur Ouyang Riping＇s story, which may insights thcsc people who want to succeed and complete oneself in favorite condition or adversity rather leave things to so-called fate.     

Belarus, A Chinese Fort in Europe

＂In recent years, we＇ve found increasing interest from Chinese investors in the Belarus economy. Please let China know, Belarus is always ready to be a true friend to China. We have built a fort in Europe for China,＂ the President of Belarus, Alexander Lukashenko told Zhou Xiaochuan, President of the Bank of China, during his visit to the capital of Minsk, on January 8th, he expressed his high praise and firm confidence in the development of Sino-Belarusian relations.     

What＇s Behind Spring Festival？

Similar to what the Christmas Day means for the westerners,the Spring Festival is the most important celebration for Chinese people.This big event according to Chinese traditional lunar calendar relaxes and pleases the whole country as the happiest gathering time of the year.National-wide crusade for going back home,too-difficult-to-get train tickets,generous family-going-out shopping,Miaohui laundering,New Year Eve reunion dinner,visiting friends and relatives,watching annual TV gala......each piece of clue reminds us of the smell of Chinese Spring Festival.     

KEY WDRDS for Foreign Investment in China

FDI(Foreign Direct Investment),a component of a country's national financlal accounts,is investment of foreign assets into domestic structures,equipment,and organizations.It does not include foreign investment into the stock markets,concession and subcontract.FDI iS thought to be more useful to a country than investments in the equity of its companies because equity investments are potentially "hot money"which can leave at the first sign of trouble,whereas FDI is durable and generally useful whether things go well or badly.     

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.     

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.