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智能增强的免授权多址接入技术
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作者 于含笑 费泽松 《中兴通讯技术》 北大核心 2024年第1期33-40,共8页
免授权多址接入技术是未来海量物联(IoT)场景的关键使能技术。在免授权接入系统中,由于用户和基站间缺少授权信息,易产生用户难识别以及用户间强干扰等问题,一方面可将免授权多址技术与非正交多址接入技术结合来缓解随机接入造成的用户... 免授权多址接入技术是未来海量物联(IoT)场景的关键使能技术。在免授权接入系统中,由于用户和基站间缺少授权信息,易产生用户难识别以及用户间强干扰等问题,一方面可将免授权多址技术与非正交多址接入技术结合来缓解随机接入造成的用户干扰问题,另一方面也可以进一步利用人工智能技术强大的数据特征提取能力,对收发机算法进行优化,以有效降低用户碰撞概率,实现海量物联场景下的大规模通信。分析了当前未来移动通信网络中多址接入技术的需求、发展历程及研究现状。指出未来需要针对全场景进行接入技术拓展和智能技术弹性演进研究,以助力智能内生多址技术发展。 展开更多
关键词 免授权接入 海量物联 非正交多址接入 人工智能
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Biomass Allocation of Scirpus mariqueter Along an Elevational Gradient in a Salt Marsh of the Yangtse River Estuary 被引量:11
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作者 孙书存 蔡永立 刘红 《Acta Botanica Sinica》 CSCD 2001年第2期178-185,共8页
Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stre... Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stress, the biomass allocations to different plant components and some related morphological parameters were examined along an elevational gradient within a salt marsh. Authors found that S. mariqueter performed best at medium elevation within the marsh, with relatively high density of shoot and individual ramet dry mass. Biomass allocation to corm was the highest at low elevations, and the least at high elevations, suggesting that a conservative strategy was adopted by the species to cope with the harsh physical conditions at the low elevation. The investment in rhizome decreased from low to high elevations, while the proportion of inflorescence mass increased, indicating that during the life history, the species shifts from predominant asexual reproduction to predominant sexual reproduction. This may be favourable for the species to colonize larger area, and to spread and persist at a meta_population level. Correlation analyses showed that sexual reproduction was inversely related to growth and asexual reproduction. However, it is difficult to determine the relationship between asexual reproduction and growth possibly because of the varied function of the corms of the species in different life history stages. 展开更多
关键词 asexual reproduction CORM salt marsh sexual reproduction life history strategy trade_off
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