共查询到20条相似文献，搜索用时 62 毫秒
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提出一种在车辆自组织网络(VANET)中应用的无线多跳视频传输实验系统的设计和实现方案及其对应的传输控制和路由选择协议.该系统将嵌入式Linux与IEEE 802.11n传输协议集成到ARM内核,由S3C6410主控模块、无线局域网网卡及LCD屏等构成.针对VANET的无线多跳视频传输场景,对视频编译码分别采用H.264和JPEG两种标准实现并对它们的压缩比、时延、传输丢包率等性能进行了理论分析和实验比较,进行了室内室外多种不同场景的实际测试.结果表明:所设计的多跳视频传输实验系统方案能够适应VANET等多种场景的应用,所提出的传输控制和路由选择协议能够保证视频传输的多跳和实时性要求. 相似文献
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车载自组织网络(VANET)一直以来受到越来越多的关注。然而,VANET的固有特性,如节点的高移动性、频繁变化的拓扑,在复杂的城市环境中为设计高效的路由协议提出了许多挑战。提出基于城市车辆网络(AGQOT)传输质量的自适应地理路由协议,作为道路路段的选择指导,一种称为传输质量(QOT)的度量被设计用来测量每个路段的性能,将路由连通性与分组传送率(PDR)相结合。在这种度量的帮助下,道路段可以逐个动态地选择,以构成最佳路由路径,避免局部最大和数据拥塞问题。提出一种改进的贪婪转发策略,使数据包沿着选定的路段转发,保证数据包传输的快速可靠。仿真结果表明,提出的协议可以提高网络在分组传输率和端到端延迟方面的性能。 相似文献
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指出传统蚁群算法在解决QoS单播路由选择问题时,受到时延和带宽的约束,为降低路由费用,容易出现陷入局部最优且收敛速度慢的现象。针对上述问题,提出一种基于精英策略的蚁群优化QoS单播路由算法,该算法利用蚁群算法原理,并引入精英策略。通过仿真模拟一个20节点的计算机网络QoS单播路由选择实例,并与传统蚁群优化(ACO)算法进行对比,仿真结果表明该算法是有效的。 相似文献
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网络中的各种应用都有其特点,因此选择一种合适的路由协议满足各种应用非常必要.本文采用NS-2对单路径路由协议和多路径路由协议的传输延时、吞吐量和丢包率等性能参数进行了分析和讨论. 相似文献
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无线传感器网络因其明显的性能优势和巨大的应用前景而受到学术界和工业界越来越广泛的重视。在无线传感器体系结构中,网络层路由协议是无线传感网络的核心问题。文章阐述了无线传感器网络的特点,路由协议的要求,并对重要的路由协议工作原理进行了技术分析,从协议性能的角度比较了各个路由协议的特点,最后在文中对WSN路由协议的研究仍存在的问题和挑战进行了论述,指出了未来无线传感器网络路由协议的研究方向。 相似文献
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以中小企业互联网络规划设计方案为背景,对企业园区网中同时存在的路由信息协议RIP、开放最短路径优先协议OSPF和增强型内部网关路由协议EIGRP等不同路由协议优缺点进行对比研究,在此基础上,分析了不同路由协议对园区网络规划与设计的影响,介绍了邻居关系建立和负载均衡的配置要求,实现了不同路由协议互联网络的搭建,并探讨了可能出现的问题以及应对方法。 相似文献
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RIP协议是一种简单但带有缺陷的路由协议。不同版本的RIP协议数据包格式内容不同,其运行在帧中继这种典型的非广播多路访问网络中,会形成不同的路由信息。论述了RIPv1与RIPv2的主要区别,以及帧中继特征,并在思科路由器上进行实验。在非广播多路访问网络的帧中继环境中,对RIP协议的路由特性进行了分析,并对RIPv2漏洞提出了优化方法。 相似文献
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本文主要针对战争环境下对路由协议的特殊安全要求,讨论了当前应用较广的几种安全路由协议,重点探讨了基于定位信息的安全型路由协议“Secure Position Aided Ad Hoc Routing”(SPAAR)相关特性。 相似文献
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王轶群 《赤峰学院学报(自然科学版)》2013,(6):20-22
作为信息化应用的载体——计算机网络的可靠性受到越来越多的重视.VRRP(虚拟路由器冗余协议)是一种选择协议,它的优势在于不需要在终端进行动态路由和路由发现协议的配置,即可获得一个高可靠性的缺省路由通道.通过以S9300系列交换机为载体,分析和研究VRRP虚拟路由器冗余性协议的原理和配置,实现园区网络的路由冗余. 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献