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Under the current TCP/IP architecture,all TCP traffics compete for network resources completely fairly,which makes it difficult to satisfy applications‘‘‘‘‘‘‘‘ versatile communication requirements.This paper presents an improved TCP congestion control mechanism where the congestion window becomes ω(1-b)W rather than(1-b)W for every window W containing a packet loss.Theoretical analysis and simulation results show that it cann be easily implemented with less additional overhead and can easily perform network resource allocation by weighted parameter ω for traffics under the similar communication environments,whic can efficiently lead to guaranteed relative quqlity of scrviccs and improve network performances. 相似文献
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传统的TCP拥塞控制算法在遇到丢包时发送速率会有剧烈抖动,不适合传输实时多媒体数据流。本文在TCP拥塞控制算法加增乘减(AIMD)基础上提出一种改进算法慢增慢减(SISD)算法。仿真结果表明:该算法同传统TCP拥塞控制算法相比,有较好的发送速率平滑性,减小了数据延时抖动,加入了多媒体流的拥塞调整机制。本算法可作为实时多媒体数据传输研究的基础,同时也改善了TCP流的传输质量。 相似文献
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TCP Reno拥塞控制机制是目前互联网中采用的主流拥塞控制算法.根据TCP Reno实现拥塞避免与拥塞控制的AIMD算法中加性因子与减性因子过于武断,对可用带宽的探测缺乏细分,造成信道利用率未达合理水平等缺陷,为此,提出一种根据拥塞窗口的增长情况进行更为平滑的信道容量探测算法,采用基于对数的增长算法和下降算法,通过N... 相似文献
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介绍了目前应用最为广泛的拥塞控制机制AIMD和一种通用的公平性评价标准——比例公平性评价标准．以及Floyd在AIMD基础上根据回路延时（RTT）不同的连接的公平性要求提出的恒定速率（CR—constantrate）窗口更新机制；在分析上述机制和评价标准在卫星网络中应用存在的缺陷的基础上，将区分服务的思想引入AIMD拥塞控制机制，提出了基于服务的AIMD算法和基于丢包率的公平性评价方法． 相似文献
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《International Journal of Hydrogen Energy》2022,47(6):3625-3632
The emerging 2D g-C2N obtained increasingly more popularity in functional materials design, and its natural porosity can easily accommodate metal atoms, making itself more suitable for energy gases storage. In this study, we employed DFT computational studies to systematically solve the electronic structure of Li-doped g-C2N monolayer, and evaluate its performance in hydrogen storage. In our calculations, we found that each pore of g-C2N can adsorb at most three Li atoms that bind with pyridinic N atoms. We also noticed that considerable amount of charges were transferred from the adsorbed Li to the pristine materials, potentially enhancing its overall conductivity. The change of electronic structure also leads to its improved performance in H2 adsorption, due to the fact that the electrostatic interactions between the adsorbed H2 and Li can be largely enhanced. The optimised configurations of the Li-doped g-C2N with multiple adsorbed H2 molecules were presented, and the fundamental mechanisms of adsorption were also investigated in details. The highest storage capacity of hydrogen by Li-doped g-C2N can reach to 7.8 wt%, much higher than the target value of 5.5 wt %, defined by the U.S department of energy (DOE). Moreover, except Li, we also found that the nitrogen atoms or the N-C bonds can also serve as active adsorption sites. The computational explorations conducted in this study actually indicates a promising prospect of alkali metals decorated 2D materials in the area of hydrogen storage; and we believe the performance of these kinds of novel materials can be further enhanced via more decent modifications. 相似文献
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With the rapid growth of rate-based services and wireless applications,improving Transmission Control Protocol (TCP) congestion control has been becoming more important in the network research field. This paper first briefly introduces the Additive-Increase Multiplicative-Decrease (AIMD) (a,b) algorithm,and then presents an improved TCP congestion control mechanism (D-AIMD) whose principles and simulation results are discussed in detail. This mechanism can be easily implemented with lower additional overheads and can efficiently improve network performance. 相似文献
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本文提出了一种可调参数AIMD算法和一种在接收端实现该算法的适合在Internet上传输多媒体流的可调参数传输控制协议。UDP不适合传输多媒体数据，因为它没有拥塞控制机制。TCP遇到单个数据包丢失传输速率就减半，会造成速率剧烈抖动，也不适合传输多媒体数据。在APTCP控制下传输的多媒体流具有良好的速率平滑性，并能够与竞争的TCP流公平的分享带宽。APTCP便于升级到组播多媒体业务，可用于非对称网络。 相似文献
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运用从头算分子动力学(AIMD)方法对均四嗪分子的热分解轨迹进行了模拟,用密度泛涵理论在B3LYP/6-311G(d,p)水平下计算了极小点和过渡态的几何结构和能量性质。然后在多种理论水平下(包括B3LYP/6-311 G(2df,2p)、G3MP2B3、G3B3、CCSD(T)/6-311G(d,p)、CCSD(T)/6-311 G(2df,2p))计算了反应物、产物和过渡态的单点能,并运用微正则变分过渡态理论(μVT)计算了均四嗪的热分解反应速率常数,得到较为准确可靠的反应信息。研究结果表明:均四嗪分子的热分解机理为协同的三键断裂,生成1个N2和2个HCN,此机理与均四嗪的光分解机理一致。 相似文献