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31.
Johann Márquez-Barja Carlos T. Calafate Juan-Carlos Cano Pietro Manzoni 《Computer Communications》2011,34(8):985-997
Wireless technologies, under the “Anywhere, Anytime” paradigm, offer users the promise of being always attached to the network. Mobile devices enabled with multiple wireless technologies make possible to maintain seamless connectivity in highly dynamic scenarios such as vehicular networks (VNs), switching from one wireless network to another by using vertical handover techniques (VHO). In this paper we present an overview of VHO techniques, along with the main algorithms, protocols and tools proposed in the literature. In addition we suggest the most appropriate VHO techniques to efficiently communicate in VN environments considering the particular characteristics of this type of networks. 相似文献
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Xu Li Hongyu HuangXuegang Yu Wei ShuMinglu Li Min-You Wu 《Computer Communications》2011,34(10):1159-1168
We consider a new application paradigm of vehicular sensor networks (VSN). Currently, vehicles are equipped with forward facing cameras to assist forensic investigations of events by proactive image-capturing from streets and roads. Due to content redundancy and storage imbalance in this in-network distributed storage system, how to maximize its storage capacity becomes a nontrivial challenge. In other words, how to maximize the average lifetime of sensory data (i.e., images generated by cameras) in the network is a fundamental problem to be solved. This paper presents, VStore, a cooperative storage solution in vehicular sensor networks for mobile surveillance, which has been designed to support redundancy elimination and storage balancing throughout the network. Compared with existing works, we propose a novel storage architecture for urban surveillance and deal with challenges in a mobile scenario. Field testing was carried out with a trace-driven simulator, which utilized about 500 taxis in Shanghai. The testing results showed that VStore can largely prolong the average lifetime of sensory data by cooperative storage. 相似文献
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根据超短波接收机的数传要求,提出基于PXI的数传总线结构,详细分析了PXI总线协议,并讨论了其实现方法,给出了相应的硬件和软件实现方案,最后利用测试板对PXI数传总线进行了测试。试验结果表明,基于PXI的数传总线完全能够满足超短波接收机的数传性能要求。 相似文献
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Design and implementation of a vehicle interface protocol using an IEEE 1394 network 总被引:1,自引:0,他引:1
A wide variety of in-vehicle devices such as camera sensors, navigation systems, telematics and communication equipments have been incorporated into a vehicle to realize Intelligent Transport Systems (ITS) applications. Because an efficient standardized network is required, ITS Data Bus (IDB) has been discussed to carry high-speed multimedia data for audio, video and other real-time ITS applications. For connecting devices in a standardized manner, the IDB network has architecture with a gateway called vehicle interface which is located between automaker’s proprietary network and the standardized IDB network. IEEE 1394 (also known as iLink or FireWire), which can transport multimedia data for consumer electronics, is a good candidate for IDB network. In this paper, we analyze the issues for existing AV/C protocol (application layer protocol over IEEE 1394) to comprise the IDB network. In addition, we designed and implemented the vehicle interface protocol as a higher layer of IEEE 1394 to address the AV/C protocol issues for realizing the whole IDB network architecture. 相似文献
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金鸡滩2号机组在运行中出现了油压装置压油泵频繁打油,受油器下游侧端盖与挡油环、端盖与小轴相互碰刮的异常运行情况,文章对此异常情况进行了分析并介绍了故障的排查处理过程,对类似机组的相同故障处理有借鉴作用。 相似文献
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设计了一种用于人体传感器网络的低功耗接收器模拟前端,电路物理层信道利用人体进行通信,并采用了一种宽带信号传输技术,可以在0.8 V电压供电,100 mV输入敏感度条件下传输20 Mb/s的数据。片上的电压偏置电路提供了50Ω的输入阻抗。放大器采用了一种低压低功耗的Cascode结构,具有58 dB的增益,25 MHz的增益带宽积。另外采用了一种结构简单,功耗极低的电流反馈型Schmitt触发器。电路采用SMIC0.13μm标准CMOS工艺设计,面积0.02 mm2,供电电压0.8 V,功耗仅为2.2 mW。 相似文献
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针对常规罗兰C接收机天地波识别方法不能有效利用信号能量的缺点,根据天波到来时间的估计与合成信号频率的分离相似的特点,提出了一种基于多信号分类算法估计天波延迟的方法.该方法在低信噪比条件下可分离出地波和天波,并能根据天波的延迟变化实时地选择接收机采样基准点的最佳位置.计算机仿真结果表明,该方法可以用于天地波的自动识别,能增加基准点处的信噪比,因而能显著提高罗兰C接收机的性能. 相似文献