共查询到17条相似文献，搜索用时 468 毫秒
1.
ZUO Dong-hong DU Xu YANG Zong-kai 《浙江大学学报(A卷英文版)》2007,8(8):1191-1198
Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks. 相似文献
2.
In this paper, the security technology of ad hoc networks is studied.To improve the previous multi-receiver signcryption schemes, an ID-based multi-message and multi-receiver signcryption scheme for rekeying in ad hoc networks is proposed.In this scheme, a sender can simultaneously signcrypt n messeges for n receivers, and a receiver can unsigncrypt the ciphertext to get his message with his own private key.An analysis of this scheme indicates that it achieves authenticity and confidentiality in the random oracle model while being of lower computation and communication overhead.Finally, for the application of our scheme in ad hoc, a threshold key updating protocol for ad hoc networks is given. 相似文献
3.
This paper proposes a novel multichannel medium access control(MAC)protocol based on CDMA that improves network performance and reduces collision probability in wireless ad hoc networks.In the scheme,the code channel is divided into common channel,broadcast channel and several data channels.Simulation results show that the proposed protocol can achieve significantly better performance than the IEEE 802.11 standard. 相似文献
4.
YANG Rui-jun XIA Qi PAN Qun-hua WANG Wei-nong LI Ming-lu 《浙江大学学报(A卷英文版)》2006,7(4):493-501
INTRODUCTION Mobile ad hoc networks are under active research focused on issues such as routing, security (Venkatra- man and Agrawal, 2003) and data management (Fan and Zhang, 2004). People have proposes many kinds of security mechanisms such as SAR (Yi et al., 2002), SRP (Papadimitratos and Haas, 2002), ARAN (San- zgiri et al., 2002), ARIADNE (Hu et al., 2005) and SEAD (Hu et al., 2002) for networks. The resource consumptions of security mechanisms are always large in mobile … 相似文献
5.
An adaptive load balancing scheme is proposed to balance the load in ad hoc networks. The new scheme can be applied in most on-demand routing protocols resulting in significant performance improvement. The proposed scheme is applied to the ad hoc on-demand distance vector (AODV) routing protocol. Simulation results show that the network load is balanced on the whole, and performance in packet loss rate, routing overhead and average end-to-end delay is also improved. 相似文献
6.
Interval standard neural network models for nonlinear systems 总被引：1，自引：0，他引：1
LIU Mei-qin 《浙江大学学报(A卷英文版)》2006,7(4):530-538
INTRODUCTION Neural networks have been successfully em- ployed for controlling nonlinear systems since the 1990’s (Narendra and Parthasarathy 1990; Hunt et al., 1992; Suykens et al., 1996). In these nonlinear control systems, neural networks have been used either for modelling the system to be controlled, or for design- ing a controller, or both. Recently, the robustness issue has been an important focus of research in neuro-control circles (Suykens et al., 1996; Wams et al., 1999; Aya… 相似文献
7.
Xin-yu Wang Xiao-hu Yang Jian-ling Sun Wei Li Wei Shi Shan-ping Li 《浙江大学学报(A卷英文版)》2008,9(10):1318-1325
This paper proposes a connected dominating set （CDS） based mobility management algorithm, CMMA, to solve the problems of node entering, exiting and movement in mobile ad hoc networks （MANETs）, which ensures the connectivity and efficiency of the CDS. Compared with Wu＇s algorithm, the proposed algorithm can make full use of present network conditions and involves fewer nodes. Also it has better performance with regard to the approximation factor, message complexity, and time complexity. 相似文献
8.
In wireless networks, data packets are lost due to channel interference and fading rather than network congestion. Thus, TCP designed for wired networks, cannot achieve a satisfying performance in wireless networks. Utilizing a cross-layer mechanism to identify the course of packet loss, we have proved that a mobile-host-centric transport protocol (MCP) can achieve higher throughput than TCP Reno and New Reno in static wireless environment. In this paper, we extend the cross-layer feedback mechanism and con... 相似文献
9.
A load-balanced minimum energy routing algorithm for Wireless Ad Hoc Sensor Networks 总被引：3，自引：0，他引：3
CAI Wen-yu JIN Xin-yu ZHANG Yu CHEN Kang-sheng 《浙江大学学报(A卷英文版)》2006,7(4):502-506
INTRODUCTION Wireless Sensor Network is one special type of wireless ad hoc networks without fixed infrastructure consisting of a collection of sensor nodes, and oper- ating on limited amount of battery energy consumed mostly in transmission and reception. In the WSNs described in Fig.1, every sensor node can sense, process data and communicate to base station (BS). WSNs have attracted much attention during the recent two years and some commercial implementations such as environmental … 相似文献
10.
Wireless sensor networks consist of hundreds or thousands of sensor nodes that involve numerous restrictions including computation capability and battery capacity. Topology control is an important issue for achieving a balanced placement of sensor nodes. The clustering scheme is a widely known and efficient means of topology control for transmitting information to the base station in two hops. The automatic routing scheme of the self-organizing technique is another critical element of wireless sensor networks. In this paper we propose an optimal algorithm with cluster balance taken into consideration, and compare it with three well known and widely used approaches, i.e., LEACH, MEER, and VAP-E, in performance evaluation. Experimental results show that the proposed approach increases the overall network lifetime, indicating that the amount of energy required for communication to the base station will be reduced for locating an optimal cluster. 相似文献
11.
在Ad hoc网络中入侵检测问题已经成为研究热点,本文首先对存在的安全隐患进行了分析描述,然后从会话过滤的角度出发,结合Ad hoc网络自身特点的基础上,提出了一种基于状态检测的入侵防护策略,用于提高整个网络的安全性. 相似文献
12.
葛文英 《安阳师范学院学报》2006,(5):45-48
目前,移动Ad Hoc网络越来越受到人们的重视。在Ad Hoc网络中,路由协议的性能优劣是一个很重要的问题。目前的协议大体可分为两类:表驱动类和按需驱动类路由协议。研究表明:表驱动类的路由协议带来了大量的路由开销,对于网络带宽比较紧张的Ad hoc网络环境,按需路由协议是更好的选择。 相似文献
13.
在Ad hoc网络中冲突控制问题一直是研究热点,本文首先对冲突进行定量的分析描述,然后从自适应按需加权的角度提出相应的冲突受限算法。该算法在保证网络连通性的前提下,兼顾节点移动性,节点度以及链路冲突尽量最小化,构建了一个冲突控制拓扑,用于实现整个网络的冲突控制,提高了网络性能。 相似文献
14.
INTRODUCTION In current Internet, most of traffic is generatedby traditional data transfer applications such asHTTP (hyper text transmission protocol), FTP (filetransmission protocol), or SMTP (small mailtransfer protocol). Usually, these elastic applica-tions are not sensitive to the delivery time of indi-vidual packet, but rather to the total transfer time ofthe data. They often use TCP, which provides re-liable end-to-end control over the “best-effort”service of IP. Beca… 相似文献
15.
End-to-end TCP(transmission control protocol)congestion control can cause unfairness among multiple TCP connections with different RTT(Round Trip Time). The throughput of TCP connection is inversely proportional to its RTT.To resolve this problem,researchers have proposed many methods. The existing proposals for RTT-aware conditioner work well when congestion level is low. However,they over-protect long RTT flows and starve short RTT flows when congestion level is high. Due to this reason,an improved method based on adaptive thought is proposed. According to the congestion level of networks,the mechanism can adaptively adjust the degree of the protection to long RTT flows. Extensive simulation experiments showed that the proposed mechanism can guarantee the bandwidth fairness of TCP flows effectively and outperforms the existing methods. 相似文献
16.
车载自组织网络（VANET）是近年来智能交通领域的研究热点之一。在VANET网络中,智能车辆通过交互共享道路环境信息,可提高交通安全水平。在现实环境中进行大规模的车载自组织网络实验,在经济性和可行性上都具有较大困难。在SUMO交通仿真基础上开发出车辆防碰撞虚拟仿真系统,通过Google Street Map获取真实道路环境（如路网、楼宇、植被等）,并结合 GEMV2软件对智能车辆在真实道路环境下的无线通讯链路质量进行评估,实现了虚拟行车交通流与车辆间无线通讯质量评估两位一体的模拟仿真,增强了车辆对周围道路交通环境的综合感知能力。 相似文献
17.
为了满足战后扫雷的实际需求,针对现有雷场探测技术的不足,设计基于多源信息同步探测、具有雷场扫描探测和疑似目标探测两种工作模式的雷场探测系统。系统由一个设置在安全位置的探测控制主机和多个具有飞行、探测功能的探测分机组成。采用基于LoRa的无线通信技术,进行LoRa无线通信模块硬件电路设计与动态自组网方式设计,并以Mesh网络拓扑实现自组网。最后,在雷场探测模拟试验场环境下对系统进行测试,在不同通信距离条件下对系统传输功率及丢包率的测试结果表明,该系统能满足雷场探测过程中的多任务处理要求。 相似文献