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- 摘要
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Inter-satellite link assignment for the laser/radio hybrid network in navigation satellite systems
摘要： The Ka inter-satellite link (ISL) has been applied in the new generation of the BeiDou Navigation Satellite System. The next move is to supplement laser ISLs to improve the communication rate and ranging accuracy. A key challenge of the hybrid inter-satellite link network is how to properly schedule the two kinds of inter-satellite links to achieve better system performance, such as robustness, short transmission delay, and the position dilution of precision (PDOP). To solve this problem, we propose a compatible scheme of the laser/radio inter-satellite link network. The topology of the laser network is optimized based on maximum connectivity and minimum time delay through a multi-objective simulated annealing algorithm. Thereafter, a two-step algorithm optimizing the downlink delay and the PDOP is presented to arrange radio inter-satellite links. The proposed method was tested in a simulated case of the BeiDou Navigation Satellite System. The optimized topologies of the laser network reached the upper limit of connectivity, which was 2 in the simulated case, and downlink delay less than 0.3 s. Compared to the radio inter-satellite link network, the hybrid one enabled higher throughput of laser satellites (more than 125 Mbps), less downlink delay (less than 10 s), and smaller average weighted position dilution of precision (WPDOP) of laser satellites (less than 1.5 for IGSOs and less than 1 for MEOs).
关键词： Multi-objective simulated annealing,Laser inter-satellite link,Hybrid network,Position dilution of precision
更新于2025-09-16 10:30:52
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hybride nanowire networks prepared by electrospinning
摘要： We prepared La1.85Sr0.15CuO4/La0.7Sr0.3MnO3 nanowire network hybrid systems by means of electrospinning. From obervation by scanning electron microscopy, the average diameter of the nanowires is around 220 nm and the average length can reach over 50 μm. The randomly aligned La1.85Sr0.15CuO4 and La0.7Sr0.3MnO3 nanowires exhibit numerous interconnects among each other and form a complicated, non woven hybrid network system. The nanowires are polycrystalline with a grain size at around 30 nm as con?rmed by transmission electron microscopy. According to four-probe electrical transportation and magnetization measurements, superconductivity of the sample is suppressed and a positive magnetoresistance e?ect is observed. Measurements of M(T ) and M(H) were carried out as well, revealing the soft magnetic character of the hybrid nanowire network samples.
关键词： LSCO,electrospinning,nanowires,LSMO,magnetization,magnetoresistance,hybrid network
更新于2025-09-10 09:29:36
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Measurement of IPTV Services on a Hybrid Access Network
摘要： Future telecommunication networks will be formed by means of different types of telecommunication systems that were used in the past. Considering expanding options of today’s smart mobile phones there is increasing pressure on telecommunication operators, who face a challenge how to cooperate across different telecommunication systems within their networks. The work focuses on the expansion of IPTV data flow on a hybrid network that is formed by the EPON and ADSL technologies. Along with the hybrid topology we focus on comparing multicast and unicast expansion of IPTV data traffic within this work.
关键词： EPON,MSE,ADSL,hybrid network,PSNR,SSIM,IPTV
更新于2025-09-10 09:29:36