共查询到20条相似文献,搜索用时 15 毫秒
1.
提出一种针对移动自组网的动态优先权队列调度机制(Dynamic Priority Queue Scheduling, DPQS)。为缓冲区设置最大、最小两个阈值;将其分为三个不同的负载阶段;然后根据当前缓冲区的负载情况动态调整各种类型数据包的优先等级;从而在不影响快速建立路由的前提下;降低数据包在网络中的传输延时;提高网络的性能。仿真结果表明DPQS机制有效地降低了网络传输延时;并对网络的吞吐量也有一定的提高。 相似文献
2.
提出一种针对移动自组网的动态优先权队列调度机制(Dynamic Priority Queue Scheduling,DPQS)。为缓冲区设置最大、最小两个阈值,将其分为三个不同的负载阶段,然后根据当前缓冲区的负载情况动态调整各种类型数据包的优先等级,从而在不影响快速建立路由的前提下,降低数据包在网络中的传输延时,提高网络的性能。仿真结果表明DPQS机制有效地降低了网络传输延时,并对网络的吞吐量也有一定的提高。 相似文献
3.
4.
本文简要介绍了车载自组织网络和移动自组织网络中两个典型的路由协议:表驱动路由协议DSDV和按需路由协议AODV;还介绍了一个实用的移动模型,使仿真实验更加接近现实。在Linux下使用网络仿真工具NS2对这两个典型协议进行仿真,并对仿真结果进行分析比较和性能评价,得出:AODV和DSDV协议都不太适用于车辆自组织网络,所以设计适合车辆网路的协议是急需解决的问题。 相似文献
5.
It is a challenge to make the routes quickly adapt to the changed network topology when nodes fail in a wireless ad hoc network. In this paper, we propose an adaptive routing protocol, which groups the network nodes into virtual nodes according to their data transfer capabilities and creates virtual-node-based routes. The protocol can accommodate the routes to node failures by adaptively pdating the virtual nodes and just-in-time using available nodes during data transmission. The simulations indicate that the proposed protocol can keep the routes failed-node-freewhen the available virtual node members cover the failed nodes scattering area. 相似文献
6.
移动自组网是一种特殊的无线移动通信网络,它由一系列带有无线收发装置的动态节点临时形成一个多跳的自治系统,因此传统网络中的路由协议不适合于移动自组网络.选播作为一类新的通信协议,能有效平衡网络负载分布和提高网络性能.本文首先描述了移动自组网络的特点及该环境下的路由协议,在此基础上提出了一种有效的选播路由协议.通过平均分组传送成功概率和平均控制字节数指标的测试表明了算法的有效性. 相似文献
7.
MANET网络中由于节点移动的随机性和无线链路的断连性,导致网络拓扑变化频繁,从而降低了数据可访问能力.提出一种基于兴趣度的协同缓存策略(IBCC).其主要思想是:针对节点转发的数据请求消息,引入ω-稳定节点集定义和兴趣度概念,定期挖掘ω-稳定节点集中具有相同兴趣度的数据形成预取集;针对回复的数据消息形成数据定位表,通过查找数据定位表将请求发送给同样拥有该数据但路由跳数较少的节点.该策略提高了在出现链路断接时节点对数据的访问能力.仿真实验结果证明该策略的有效性. 相似文献
8.
This paper reports about our experience in designing and developing Chameleon, a highly portable and adaptable group communication framework for smartphones. Chameleon owes its level of portability to several design choices, including the following: (i) a layered architecture, where the headers of each layer have a standard XML‐based format, enabling automatic, error‐resistant generation of efficient serialization code in any platform; (ii) reliance only on the J2ME library, which serves as least common denominator for Java dialects and facilitates automatic translation to.NET; (iii) having flexible membership models; and (iv) supporting multiple concurrent protocol stacks.Through a single codebase, Chameleon is currently available as an open‐source project for J2ME, J2SE, Android,.NET CF, and.NET. Chameleon is easily extendable and is bundled with tools, configurations, and third‐party code tuned in a way that lifts some of the burden normally associated with multiplatform development for smartphones. Both the header generation from XML and automatic translation to.NET features of Chameleon are readily available to any application that is based on it. Chameleon's threading model separates between execution of internal layers and application's code and by that protects one from the other. As we describe in the paper, it simplifies layers' development and allows the protocol stack to easily block application calls when this is required by internal algorithms. Additionally, this model simplifies testing, and an extensive testing framework is supplied along with Chameleon, which is also usable for testing of application‐specific layers. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
Romit Roy Choudhury Krishna Paul Somprakash Bandyopadhyay 《Autonomous Agents and Multi-Agent Systems》2004,8(1):47-68
Supporting mobility in a multi hop wireless environment like the MANET still remains a point of research, especially in the context of time-constrained applications. The incapacity of ad hoc networks to offer services of the likes of static or infratructured networks may be attributed to two major reasons. One, unpredictable mobility of hosts cause location-transparent-packet-delivery to be implemented only at the expense of large control overhead. Two, the lack of central control causes connection management and scalability to be major problems in the multi hop environment. In this paper we propose an efficient agent based routing mechanism that not only incurs minimal overhead, but also lays the foundation for additional functionalities as network management and real time applications. In other words, we show that the agent framework makes the MANET robust and survivable under stringent system constraints. 相似文献
10.
对现有的应用于移动互联网的P2P技术方面的研究进行了分析.首先介绍了P2P技术和移动互联网的概念,并提出将P2P技术应用在移动互联网所面临的挑战和应用模式.其次,分别针对集中式架构、超级节点体系架构和ad hoc架构对应用于互联网的P2P网络体系架构进行了阐述.再其次,针对移动终端的两种接入模式,分别在资源定位算法和跨层优化两个方面进行了介绍.对各关键技术的特点进行了详细的分析,指出其存在的不足.最后,对未来的工作进行了展望. 相似文献
11.
12.
由于节点的移动性、无线链路的带宽有限、可获得的能量有限等原因,对移动Ad hoc网络进行路由提出了具有挑战性的要求。基于位置的路由协议由于不必维护明确的路由,在这种高度动态的网络中具有很好的扩展性。该文通过仿真将一种基于位置的贪婪转发路由:基于改进进程无信标路由(IPPBBLR),与一种基于拓扑的路由:动态源路由(DSR)进行了性能比较。仿真结果表明基于位置的路由比基于拓扑的路由在移动的情况下可以达到更高的发送成功率和更小的端到端延迟,且端到端延迟几乎不受移动速率的影响。 相似文献
13.
为了提高车载自组网的性能和频谱利用率,多接口动态频谱分配技术成为车载自组网的研究热点。介绍了车载自组网动态频谱分配算法的关键设计基础,对多接口多信道网络技术的发展现状进行了分类阐述,对车载自组网动态频谱分配技术的研究进行了展望。 相似文献
14.
移动ad hoc网络是一种新型的无线移动网络,因其特有的路由多跳性、无中心的控制分布性以及拓扑动态性,使得现有网络中的安全机制不能完全应用于移动ad hoc网络。文中探讨了移动ad hoc网络特有的各种安全漏洞以及相应的对策中存在的各种不足,并与现有网络中的安全对策进行了较深入的比较,从而总结出该领域研究的发展趋势,并指出了几个值得重视的研究方向。 相似文献
15.
移动ad hoc网络由于其动态拓扑、无线信道以及各种资源有限的特点,特别容易遭受拒绝服务(DOS)攻击.在分析传统防御机制的基础上,提出了移动ad hoc网络中一种新的DOS攻击防御机制--基于优先级和缓存控制,着重保护节点的资源. 相似文献
16.
移动ad hoc网络中DOS攻击及其防御机制 总被引:8,自引:0,他引:8
移动ad hoc网络由于其动态拓扑、无线信道以及各种资源有限的特点,特别容易遭受拒绝服务(DOS)攻击.提出了移动ad hoc网络中一种新的DOS攻击模型——ad hoc flooding攻击及其防御策略.该攻击主要针对移动ad hoc网络中的按需路由协议,如AODV,DSR等.ad hoc flooding攻击是通过在网络中泛洪发送超量路由查询报文及数据报文,大量地占用网络通信及节点资源,以至于阻塞节点正常的通信.分析ad hoc flooding攻击之后,提出了两种防御策略:其一是邻居阻止,即当入侵者发送大量路由查询报文时,邻居节点降低对其报文的处理优先级,直至不再接收其报文.其二是路径删除,即目标节点将入侵者发送攻击报文的路径删除,以阻止其继续发送攻击报文.模拟实验证实,通过这两种方法的结合.能够有效地阻止网络中的ad hoc flooding攻击行为. 相似文献
17.
由于广域网性能的巨大提高和功能强大且价格低廉的计算机不断增多,网格计算以一种极具有前途和吸引力的新范式出现。网格计算是集成地理位置分布,异构,多领域资源的一种平台,它提供透明、安全、同等、高性能资源共享。要获取计算网格中潜在的能量,设计一种有效和高效的网格资源调度算法很重要。网格独特的特点使得网格环境下的资源调度是相当复杂的。本文将重点设计一种新的基于免疫算法的网格资源调度算法。 相似文献
18.
无线传感器网络具有与传统网络不同的特点,且与应用高度相关。传统网络及移动自组织网络的路由协议不能有效地用于无线传感器网络,因而研究人员提出了众多的路由协议。在介绍了无线传感器网络的特点及路由协议设计的关键问题之后,总结分析了现存的路由协议的分类方法,并对各类路由协议从路由策略、路由协议的特点、性能等多方面进行了对比分析,指出了各类路由协议的优缺点及其包含的路由协议。最后总结出未来的研究热点和发展趋势。 相似文献
19.
A. C. Sodan 《Concurrency and Computation》2005,17(15):1725-1781
Loosely coordinated (implicit/dynamic) coscheduling is a time‐sharing approach that originates from network of workstations environments of mixed parallel/serial workloads and limitedsoftware support. It is meant to be an easy‐to‐implement and scalable approach. Considering that the percentage of clusters in parallel computing is increasing and easily portable software is needed, loosely coordinated coscheduling becomes an attractive approach for dedicated machines. Loose coordination offers attractive features as a dynamic approach. Static approaches for local job scheduling assign resources exclusively and non‐preemptively. Such approaches still remain beyond the desirable resource utilization and average response times. Conversely, approaches for dynamic scheduling of jobs can preempt resources and/or adapt their allocation. They typically provide better resource utilization and response times. Existing dynamic approaches are full preemption with checkpointing, dynamic adaptation of node/CPU allocation, and time sharing via gang or loosely coordinated coscheduling. This survey presents and compares the different approaches, while particularly focusing on the less well‐explored loosely coordinated time sharing. The discussion particularly focuses on the implementation problems, in terms of modification of standard operating systems, the runtime system and the communication libraries. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
20.
把门限秘密共享技术应用到移动自组网中,可以构建一个能提供高效可靠安全保证的通信系统。本文详细描述了该系统的结构和网络层的设计以及相关的安全问题,最后对一典型应用场景进行了实验。实验表明该设计方案可行.使得系统安全性更高.更加高效、可靠。 相似文献