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521.
BGP协议通过触发全局、反应式收敛应对网络拓扑和策略变化,然而由于其收敛时间过长、收敛过程中大量AS经历不可达、环路,造成大量转发中断,难以支持VoIP、远程医疗等关键业务的应用。本文提出了一种基于备份AS通告的新型域间路由协议BA-BGP,在不影响BGP协议动态性的基础上,通过在更新报文中增加备份AS属性,使AS节点可以获取到达目标的备份AS地址,当节点面临瞬时失效时可将报文封装转发到与备份AS关联的路径,从而降低了转发中断。大量模拟实验证明,通过采用具有互联网特征的拓扑以及广泛采用的BGP策略,BA-BGP有效降低了链路失效引起的瞬时失效率与转发中断时间,增强了网络可靠性。 相似文献
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Business relationships in internet-based electronic markets: the role of goodwill trust and transaction costs 总被引:2,自引:0,他引:2
Raluca Bunduchi 《Information Systems Journal》2005,15(4):321-341
Abstract. Transaction costs and goodwill trust, which differentiate between transactional and collaborative relationships, were found in existing research to play a significant role in the way organizations use internet technologies to manage their relationships with customers and suppliers within electronic markets (EM). However, a thorough investigation of role that the two dimensions play together in shaping the use of EM is lacking from the mainstream literature. This research addresses transaction costs and goodwill trust together to clarify the transformations that internet use has brought on the nature of interorganizational relationships that develop between EM players. The research finds the use of EM in collaborative relationships is governed by trade-offs between different outcomes that different EM functionalities have on organizational objectives. Organizations assess these trade-offs, and select those functionalities that best serve to achieve their collaborative relational objectives. In contrast, no trade-offs are find in the transactional model, as the use of EM here is driven principally by transaction cost reductions. 相似文献
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OFDM系统在多径衰落信道下的时钟同步 总被引:2,自引:1,他引:2
为消除时钟同步误差对正交频分复用(OFDM)系统的影响,提出了一种可工作在多径衰落信道下的时钟同步方法.该方法分为时钟频偏估计和时钟频偏补偿两个步骤,在估计时钟频偏时,利用了相邻符号的相邻导频之间的相关性;在补偿时钟频偏时,采用了数字内插环路,这使得时钟同步模块可在全数字接收机中实现.该方法的一个好处是,当存在载波频偏时仍可正常工作,这说明时钟同步可在载波同步之前完成.结果表明,该方法具有足够大的时钟频偏捕捉范围,可用于IEEE802.11a系统和DVB-T系统的接收机中. 相似文献
527.
Enumeration and Evaluation of Small Orthogonal Latin Hypercube Designs for Polynomial Regression Models
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Haralambos Evangelaras 《Quality and Reliability Engineering International》2016,32(7):2381-2389
In this paper, we construct and evaluate all nonisomorphic Latin hypercube designs with n≤16 runs, the use of which guarantee that the estimates of the first‐order effects are uncorrelated with each other and also uncorrelated with the estimates of the second‐order effects, in polynomial regression models. The produced designs are evaluated using well‐known and popular criteria, and optimal designs are presented in every case studied. An effort to construct nonisomorphic small Latin hypercubes in which only the estimates of the first‐order effects are required to be uncorrelated with each other has also been made, and new designs are presented. All the constructed designs, besides their stand‐alone properties, are useful for the construction of bigger orthogonal Latin hypercubes with desirable properties, using well‐known techniques proposed in the literature. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
528.
Growing Oxide Nanowires and Nanowire Networks by Solid State Contact Diffusion into Solution‐Processed Thin Films
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Colm Glynn David McNulty Hugh Geaney Colm O'Dwyer 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(43):5954-5962
New techniques to directly grow metal oxide nanowire networks without the need for initial nanoparticle seed deposition or postsynthesis nanowire casting will bridge the gap between bottom‐up formation and top‐down processing for many electronic, photonic, energy storage, and conversion technologies. Whether etched top‐down, or grown from catalyst nanoparticles bottom‐up, nanowire growth relies on heterogeneous material seeds. Converting surface oxide films, ubiquitous in the microelectronics industry, to nanowires and nanowire networks by the incorporation of extra species through interdiffusion can provide an alternative deposition method. It is shown that solution‐processed thin films of oxides can be converted and recrystallized into nanowires and networks of nanowires by solid‐state interdiffusion of ionic species from a mechanically contacted donor substrate. NaVO3 nanowire networks on smooth Si/SiO2 and granular fluorine‐doped tin oxide surfaces can be formed by low‐temperature annealing of a Na diffusion species‐containing donor glass to a solution‐processed V2O5 thin film, where recrystallization drives nanowire growth according to the crystal habit of the new oxide phase. This technique illustrates a new method for the direct formation of complex metal oxide nanowires on technologically relevant substrates, from smooth semiconductors, to transparent conducting materials and interdigitated device structures. 相似文献
529.
Vassilis Dalakas Eleftherios Kofidis 《International Journal of Satellite Communications and Networking》2020,38(4):382-394
In the context of the on‐going evolution of satellite communications (SatCom) systems to their next generation, and in the direction of their integration with fifth generation (5G) terrestrial networks, it is of interest to study in depth the applicability in realistic SatCom of waveforms that have shown promise to meet the 5G requirements. This paper presents a comparative study, based on total degradation (TD) over a range of output back‐off (OBO) values, on out‐of‐band emission and spectral efficiency, of frequency division multiple access (FDMA) schemes employing offset quadrature amplitude modulation‐based filter bank multi‐carrier (FBMC /OQAM), classical orthogonal FDMA (OFDMA), and their single‐carrier counterparts to illustrate the potential gains from the integration of the FBMC waveforms in the satellite context and standards. The air interface simulated follows the digital video broadcasting (DVB) family of standards for the satellite uplink, considering both time and frequency synchronization impairments and two typical input constellations. Our results confirm the superiority of the single‐carrier (SC) schemes in such a nonlinear environment. The SC‐FBMC waveform is shown to be the most practical candidate since it is shown to attain a TD performance similar to that of SC‐OFDM at absolutely no cost in spectral efficiency. 相似文献
530.
Amal Guezmil Hanen Berriri Remus Pusca Anis Sakly Raphael Romary Mohamed Faouzi Mimouni 《Asian journal of control》2019,21(1):33-42
This paper presents a robust fault tolerant control for an induction motor in presence of inter‐turn short‐circuit fault. The control strategy is based on Backstepping approach and high order sliding mode observer. That ensures a high‐performance control and a good dynamic in presence of inter‐turn short‐circuit fault. The stability of the Backstepping control is proved by Lyapunov theory. A high order sliding mode observer is used for rotor flux estimation. The performances of the fault tolerant control scheme will be examined via numerical simulation and validated through hardware implementation using MATLAB/Simulink with dSpace signal card. The analysis' results show the robustness of the proposed method for the tolerance of the inter‐turn short‐circuit fault. 相似文献