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《电子制作.电脑维护与应用》2017,(24)
针对AODV协议在物联网应用场景下存在的路由不稳定、数据丢包率高、时延大的问题,提出了一种基于AODV的物联网路由改进算法。该算法将信号接收强度作为路由建路的一个指标,当节点信号接收强度低于门限值时发送警告消息报文通知源节点重新发起建路请求。该改进算法能够提前识别不可靠中继节点并在链路中断前寻找新的传输路径。NS2仿真实验结果表明,与之前的AODV协议相比改进后的算法拥有更低的丢包率和时延。 相似文献
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一个优化的AODV路由协议 总被引:2,自引:0,他引:2
为了减少建立路由所产生的延时,AODV路由协议允许拥有积极路由的中间节点响应路由请求,而不考虑该节点当时的负荷,这样虽然快速地建立了路由,但并不一定能有效地传输数据。针对这一问题,提出了一个改进方法,在改进的AODV路由协议中,以节点的等待发送的数据包队列长度来衡量一个节点的负荷大小,在路由发现的过程中,中间节点根据自己负荷的大小而以不同的方式响应路由请求,使数据流不在某些路段上过于集中。仿真结果表明改进的协议和原协议相比,降低了端到端的延时和丢包率,提高了传输效率。 相似文献
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为了减少建立路由所产生的延时,AODV路由协议允许拥有积极路由的中间节点响应路由请求,而不考虑该节点当时的负荷,这样虽然快速地建立了路由,但并不一定能有效地传输数据.针对这一问题,在AODV的基础上对一种多路径路由方法MP-AOMDV进行了优化.这种优化的协议我们称为EMP-AOMDV(Enhanced Ad hoe On-demand Multi-path Vector Routing Protocol).结果表明改进的协议和原协议相比,降低了端到端的延时和丢包率,提高了传输效率. 相似文献
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为了减少建立路由所产生的延时,AODV路由协议允许拥有积极路由的中间节点响应路由请求,而不考虑该节点当时的负荷,这样虽然快速地建立了路由,但并不一定能有效地传输数据。针对这一问题,在AODV的基础上对一种多路径路由方法MP-AODV进行了优化。并结合主动式路由机制,进一步降低了链路失效。仿真结果表明改进的协议和原协议相比,降低了端到端的延时和丢包率,提高了传输效率。 相似文献
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针对车载移动ad hoc网络的特点,从路由断裂的角度在原理和理论上分析了车载移动ad hoc网络路由不稳定的各种情况,在分析结论的基础上提出了一种不依赖GPS信息的基于节点相对稳定性的类AODV路由协议RSBA(Relative Stability Based AODV Routing Protocol),通过可行性分析及实验仿真证明了新协议比AODV协议更适合节点密度较高的城市车载环境,具有较低的路由断链率和路由负载,有效降低丢包率,可扩展性提高,同时验证了对车载移动ad hoc网络路由稳定性分析策略和结论的正确性。 相似文献
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移动Ad Hoc网路AODV路由协议的改进 总被引:1,自引:0,他引:1
针对移动Ad Hoc网络AODV路由协议的路由维护的缺点,提出了AODV-BR路由协议,即具有备份路由的AODV路由协议。新协议通过为网络中的连接链路增加一条备份路由提高了AODV路由维护的性能。仿真实验表明AODV-BR有效减少了网络中链路中断的数量,降低了丢包率。 相似文献
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在AODV路由协议的路由维护阶段,当节点检测到链路中断时,会采取一种链路修复机制,然而该机制的实施难以避免数据包的丢失和传输时延的增加,针对这个问题本文提出一种对AODV协议的改进方案。该方案通过计算节点间的链路生存期,在AODV协议的路由发现阶段引入优先节点机制,在路由维护阶段引入链路中断避免机制。仿真实验结果表明,改进的AODV路由协议减少了RREQ消息的数量,降低了丢包率,并且缩短了传输时延,特别适用于节点密度较大的车载网络。 相似文献
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地图匹配( MM)算法通过粒子滤波( PF)利用室内地图信息来抑制基于惯性传感器的室内定位系统的误差累计。利用区域生长( RG)算法结合当前步长和方向信息在地图上找到合理的落脚范围,并以此来判断粒子的有效性。这种方法能有效改善地图配准算法的实用性和计算复杂度。提出一种改进的零速度( ZV)检测算法能准确提取步伐信息,间接提升了零速度更新( ZUPT)算法和地图配准算法的精度。实验结果表明:该算法的定位误差小于1.0%,定位精度比单纯的航位推算( DR)算法平均提高了5.97%。 相似文献
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This research investigates the impact of intellectual capital components on the competitive advantage in the Jordanian telecommunication companies. The empirical findings indicate that the relational capital and the structural capital have positive impact on competitive advantage. Both the relational capital and the structural capital account for 48.4% of the competitive advantage. It is unexpected to find that the human capital does not have a significant direct impact on competitive advantage. However, it is valid to state that the human capital indirectly and significantly influences competitive advantage as it is embedded in the relational capital. The effect of the relational capital on competitive advantage is moderated by gender and age. The effect is strongest among younger men. In the case of the structural capital its effect is moderated by gender only such that the effect is slightly stronger for females rather than males. 相似文献
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一、引言计算机仿真接口界面,随着计算机软硬件的不断提高也在快速地变化着。从其发展趋势中我们不难看出这一点:从早期的命令行提示编辑Command Line,到全屏幕菜单编辑(Menu based Editor),再到图形用户界面Graphic User In-terface(GUI),界面在不断追求如何更好地适应用户、与用户更直接地交互。其具体特点包括自然而又丰富的色彩、逼真而又完美的几何造型、柔和而又动听的环境声响、质感而又具有力反馈的实物等。这些人们所需要的真实感,一种技术是难以胜任的,它需要各种软、硬件技术的综合与集成。从目前的趋 相似文献
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S. Suja Priyadharsini 《Applied Soft Computing》2012,12(3):1131-1137
Electroencephalography (EEG) is the recording of electrical activity of neurons within the brain and is used for the evaluation of brain disorders. But, EEG signals are contaminated with various artifacts which make interpretation of EEGs clinically difficult. In this research paper, we use a soft-computing technique called ANFIS (Adaptive Neuro-Fuzzy Inference System) for the removal of EOG artifact, combined EOG and EMG artifact. Improvement in the output signal to noise ratio and minimum mean square error are used as the performance measures. The outputs of the proposed technique are compared with the outputs of techniques such as neural network, based on ADALINE (Adaptive Linear Neuron) and adaptive filtering method, which makes use of RLS (Recursive Least Squares) algorithm through wavelet transform (RLS-Wavelet). The obtained results show that the proposed method could significantly detect and suppress the artifacts. 相似文献
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The Prize-collecting Steiner Tree Problem (PCSTP) is a well-known problem in graph theory and combinatorial optimization. It has been successfully applied to solve real problems such as fiber-optic and gas distribution networks design. In this work, we concentrate on its application in biology to perform a functional analysis of genes. It is common to analyze large networks in genomics to infer a hidden knowledge. Due to the NP-hard characteristics of the PCSTP, it is computationally costly, if possible, to achieve exact solutions for such huge instances. Therefore, there is a need for fast and efficient matheuristic algorithms to explore and understand the concealed information in huge biological graphs. In this study, we propose a matheuristic method based on clustering algorithm. The main target of the method is to scale up the applicability of the currently available exact methods to large graph instances, without loosing too much on solution quality. The proposed matheuristic method is composed of a preprocessing procedures, a heuristic clustering algorithm and an exact solver for the PCSTP, applied on sub-graphs. We examine the performance of the proposed method on real-world benchmark instances from biology, and compare its results with those of the exact solver alone, without the heuristic clustering. We obtain solutions in shorter execution time and with negligible optimality gaps. This enables analyzing very large biological networks with the currently available exact solvers. 相似文献
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Wavelet-based envelope features with automatic EOG artifact removal: Application to single-trial EEG data 总被引:1,自引:0,他引:1
Wei-Yen Hsu Chao-Hung LinHsien-Jen Hsu Po-Hsun ChenI-Ru Chen 《Expert systems with applications》2012,39(3):2743-2749
In this study, we propose an analysis system for single-trial classification of electroencephalogram (EEG) data. Combined with automatic EOG artifact removal and wavelet-based amplitude modulation (AM) features, the support vector machine (SVM) classifier is applied to the classification of left finger lifting and resting. Automatic EOG artifact removal is proposed to eliminate the EOG artifacts automatically by means of independent component analysis (ICA) and correlation coefficient. The features are then extracted from the discrete wavelet transform (DWT) data by the AM method. Finally, the SVM is used for the discriminant of wavelet-based AM features. Compared with EEG data without EOG artifact removal, band power features and LDA classifier, the proposed system achieves promising results in classification accuracy. 相似文献
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心电信号是典型的强噪声下的非平稳微弱信号,减小噪声的干扰对心电信号的分析有着十分重要的意义,因此,有效的滤波方法一直是该领域学者关注的热点问题。本文在基于小波变换心电信号分析研究基础上,针对小波去噪时分解只作用于低频部分,从而忽略了高频区域中一部分有用信号的问题,提出了一种采用改进小波包理论实现心电信号去噪的方法,利用小波包在消除信号噪声方面具有更为精确的局部分析能力的特点,采用了‘db4’小波和"最优基"选择的方法,对心电信号进行消噪。以MIT-BIH心电数据库中心律失常数据仿真实验,得到了较理想的去噪效果。对比该方法与小波滤波去噪,发现基于小波包的心电信号去噪具有更优良的去噪性能。 相似文献
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VoIP认证与计费的设计与实现 总被引:1,自引:0,他引:1
基于RADIUS的VoIP认证系统,采用分散受理、集中管理的接入认证管理体系,数据集中存放在认证中心(RADIUS服务器),用户身份认证由PC向网守发起,网守通过RADIUS协议向认证中心的认证服务器发起认证请求。这样,可以保证用户安全地使用网络资源,以确保用户身份的合法性。同时其落地话单经过处理,可进行计费及其它帐务处理。文中论述了RADIUS对VoIP的支持,提出了一个Gatekeeper与RADIUS结合的整体解决方案。 相似文献