共查询到20条相似文献，搜索用时 70 毫秒
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机会网络是一种通过节点移动建立通信链路的无线自组织网络,一般通过消息复制的路由策略传递信息。但该方式将导致链路中存在大量消息副本,对节点缓存形成巨大压力,造成网络拥塞。针对该情况,结合Prophet算法,充分考虑节点缓存对链路状态及传输概率的影响,设计限制消息最大副本数量与及时删除节点缓存中不必要数据包的缓存管理机制,同时在Prophet算法中考虑了缓存比因素。仿真结果表明,该算法可以有效提高消息投递率,降低网络消耗。 相似文献
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针对机会网络的路由算法基本上是考虑完全合作情况下进行设计的.本文对节点的合作性进行了分析,在机会网络环境ONE平台上,通过不同的转发概率对传染路由算法Epidemic的合作性进行了测试和分析.仿真结果表明,节点之间的合作性对路由算法的性能有着不同程度的影响. 相似文献
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影响机会网络路由性能的因素较多,为进一步研究机会网络中路由算法对路由性能的影响,从提高机会网络路由性能的角度出发,研究了如何在路由算法中加入控制消息复制和删除冗余消息对机会网络路由的影响。仿真结果表明,这两种机制的加入能有较改进路由的综合性能,显著提高交付率,减少路由开销,降低传输延迟。 相似文献
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针对机会路由的候选转发集中存在恶意节点导致网络性能下降问题,提出一种计算节点信任度的评估模型。使用贝叶斯公式计算节点的直接信任度,根据节点的代数连通度得到间接信任度,利用信息熵的概念得到综合信任度。为高效辨别出候选转发集中的恶意节点,预先设定信任度阈值[β]。提出一种基于节点信任度的机会路由算法TBOR。TBOR利用信任模型初始化候选集中每个节点的综合信任度,再利用信任度阈值判断潜在的恶意节点,并将信任度大于信任度阈值的节点添加到候选转发集。实验结果表明,TBOR能高效识别并剔除候选转发集中的恶意节点,具有较高的检测率,保证了数据可靠传输。 相似文献
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由于复杂度低、扩展性好，地理位置路由广泛应用于无线传感网络(WSN)。传统地理位置路由只依据节点位置决策下一跳转发节点，并没有考虑节点能耗。为此，提出转发节点优化的地理位置路由(FNO-GR),旨在提升网络寿命，减少死亡节点数。FNO-GR路由构建邻居节点集，依据离信宿距离，从邻居节点集中选择候选转发节点，并考虑节点剩余能量，从候选转发节点中选择最优的节点作为下一跳转发节点。仿真结果表明，与最短地理位置路由(SGR)协议相比，FNO-GR路由的平均网络寿命提升约5.08%,死亡节点数下降了约7.99。 相似文献
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ZigBee网络的传统算法(簇树路由算法和AODVjr路由算法)在发现路由过程中节点能耗较大。为此,结合节点能量、簇树路由算法和AODVjr路由算法,提出一种改进的ZigBee网络路由算法。该路由算法选择路由时尽量避免能量较低的节点,选择最佳路径,维持网络稳定性。仿真结果表明,改进后的算法能有效降低整个网络总体能耗,合理分配网络负载,大大降低了死亡节点数量,从而延长整个网络的使用寿命。 相似文献
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为了延长传感器网络生存时间,多跳路由协议一直是无线传感器领域的研究热点。其中多跳分簇的路由协议（MHLEACH） 不仅能扩展通信范围,还可以均衡分配节点能耗,从而有效提高了能量利用率。但该方法存在的问题是若选中的簇首距离基站太远,则会耗费较多能量。同时,簇群链路分布的不均匀也可能使一些靠近基站的簇首更频繁地转发数据。为解决该问题,提出一种改进算法RSSI-Mean-Filter-MHLEACH（简称RMF-MHLEACH）,该算法能对接收路由消息时获得的邻居节点信号强度与邻居表内节点剩余能量信息进行比较分析,最后找出最优的上层转发节点,从而使各节点在保证通信质量的同时,也能合理分担簇首的能量消耗。 相似文献
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分子通信是纳米网络的主要通信方式之一,是一种以生物化学分子作为信息载体的短距离通信技术。为了提高分子通信中的传输速率,将地理机会路由算法中选择候选节点的条件由比较距离大小优化为比较浓度值大小。在此基础上建立分子通信模型,并利用MATLAB进行实验仿真。对实验结果进行对比分析发现,以浓度作为判定条件的地理机会路由算法更优。 相似文献
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针对移动Ad hoc网络,在AODV路由算法的基础上研究了一种MCR路由算法,MCR对AODV中的路由搜索和路由维护机制进行了扩展,用来解决多径路由问题。通过NS—2平台的仿真结果表明MCR在增加少量网络开销的情况下,提高了数据包的转发率,降低了丢包率,并减少了时延,从而有效地减少了网络拥塞。 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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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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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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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 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
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YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献