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一种基于联络历史的车载容迟网络路由算法 被引量:1
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作者 宋志华 暴建民 +1 位作者 谢元发 周雅 《计算机技术与发展》 2016年第7期196-199,共4页
移动车载容迟网络(VDTN)是一种特殊的容忍延迟网络,其消息从一端到另一端由移动的车辆节点携带转发。由于不同源节点和目的节点之间端到端通信路径不存在,因此,移动车载容迟网络中端到端的联系是松散的,且导致传递消息至目的节点的可能... 移动车载容迟网络(VDTN)是一种特殊的容忍延迟网络,其消息从一端到另一端由移动的车辆节点携带转发。由于不同源节点和目的节点之间端到端通信路径不存在,因此,移动车载容迟网络中端到端的联系是松散的,且导致传递消息至目的节点的可能性大幅度减小。因此,在移动车载自组织网络下应用的一系列路由算法不能很好地应用于VDTN。所以在VDTN中,路由算法成为一项具有挑战性的任务。文中提出了一种基于节点之间的联络历史的路由算法(CONHR),指的是通过已有联络历史记录的移动节点,比较中继计数区域中数值的大小,选择出最佳的移动节点,让其携带并转发消息至目的节点。这种历史记录包含每个移动节点过去遇到的中继节点的信息。结果显示,基于节点之间联络历史的路由算法(CONHR)与其他算法在消息投递率、平均时延、开销比上具有更好的表现。 展开更多
关键词 移动车载容迟网络 联络历史 CONHR算法 容忍延迟网络
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Development history and accessibility evolution of land transportation network in Beijing-Tianjin-Hebei region over the past century 被引量:6
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作者 陈娱 金凤君 +2 位作者 陆玉麒 陈卓 杨宇 《Journal of Geographical Sciences》 SCIE CSCD 2018年第10期1500-1518,共19页
From the development of modern transportation to the current era of high-speed transportation networks, the Beijing-Tianjin-Hebei(BTH) region has always played a national leading role in land transportation developmen... From the development of modern transportation to the current era of high-speed transportation networks, the Beijing-Tianjin-Hebei(BTH) region has always played a national leading role in land transportation development of China. In order to explore the long-term evolutionary characteristics of land transportation in the BTH region, this paper utilized a temporal scale of 100 years to systematically interpret the development process of the land transportation network. Taking 13 cities within the BTH region as research anchor cities, we took into account "leaping" mode of transportation in order to investigate the evolution of accessibility. Our research shows the following results:(1) The land transportation network in the BTH region has undergone five stages of development: the initial period of modernization(1881–1937); the period of stagnation of transportation development(1937–1949); the network expansion period(1949–1980); the period of trunk construction(1980–1995), and the period of high-speed transportation network development(1995–present). The network structure centered around Beijing has existed from the outset of modern transportation development.(2) The accessibility spatial pattern of land transportation in BTH region has evolved from expansion along traffic corridors to the formation of concentric circles. The stratified circular structure of transportation in anchor cities has gradually developed into a contiguous development pattern.(3) There are clear hierarchical differences in the transportation structures of anchor cities. Beijing has always been at the top of this hierarchy, while the hierarchical position of Zhangjiakou has fallen noticeably since 1949. The Beijing-Tianjin region was the first region to form a short-duration transportation circle structure, while the transportation advantages of the central part of Hebei Province, which is located in the center of the BTH transportation region, have yet to be realized. 展开更多
关键词 Beijing-Tianjin-Hebei region land transportation network historical evulution ACCESSIBILITY circle structure
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