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便携式PET数据无线传输的可行性探讨 总被引：1，自引：0，他引：1
提出一种新的便携式PET中数据高速传输的方法,并验证其可行性.便携式PET在进行检测时,由于探测器的移动导致了有线数据传输的困难.有别于以往采用的旋转光纤接头的方法,提出在狭小区域内应用高速无线传输技术来解决数据的连续传输问题,主要评测了无经传真(802.11g)的实际性能,采用多信道同时传输时,在信道独立条件下获得的总传输速率等于各信道速率之和,以此得到更高的传输速率来满足便携式PET大数据量的连续高速传输,在方便被检测体的自由活动方面显示了潜在的应用前景. 相似文献
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《International Journal of Digital Earth》2013,6(2):158-184
Abstract The Global Positioning System (GPS) is expected to play an integral role in the development of digital earth; however, the GPS cannot provide positioning information in regions where a majority of the population spends their time, that is, in urban and indoor environments. Hence, alternate positioning systems that work in indoor and urban environments should be developed to achieve the vision of digital earth. Wi-Fi-based positioning systems (WPS) stand out because of the near-ubiquitous presence of the associated infrastructure and signals in indoor environments. The WPS-based fingerprinting is the most widely adopted technique for position determination, but its accuracy is lower than that of techniques such as time of arrival and angle of arrival. Improving the accuracy is still a challenging task because of the complex nature of the propagation of Wi-Fi signals. Here, a novel server-based, genetic-algorithm-optimized, cascading artificial neural network-based positioning model is presented. The model is tested in 2D and 3D indoor environments under varying conditions. The model is thoroughly investigated on a real Wi-Fi network, and its accuracy is found to be better than that of other well-known techniques. A mean accuracy of 1.9 m is achieved with 87% of the distance error within the range of 0–3 m. 相似文献
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把握人类活动的时空特征是地理学研究中探究人地关系、提升人类福祉的重要基础和核心内容,日益普及的Wi-Fi网络能够为此提供可靠的数据支持。为明确Wi-Fi数据融入地理学研究的切入点和发展方向,论文通过与GPS、手机信令、蓝牙等位置感应数据的比较,认为Wi-Fi数据具有更高的采样精度和更强的采样代表性,能够获取个体在室内外各类城市空间的连续活动轨迹,支撑精细尺度下的人类活动研究。通过系统梳理人群活动状态监测、个体间的社会关系识别、建筑物的功能识别和降低隐私泄露风险等方面的研究进展,认为Wi-Fi数据将会在基于实时动态人口数据的城市功能设施规划、融合多源数据的人地关系探究、以居民福祉为导向的宜居城市建设等方面具有应用前景,有望成为地理学研究人类活动的新支点。 相似文献
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由于GPS不能满足用户对室内定位的需求,研究并开发基于Wi-Fi和Android平台的室内定位系统,利用位置指纹匹配算法和Kalman滤波实现室内定位。实验结果表明,该系统具有良好的实时动态定位效果。 相似文献
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本文主要针对地震废墟下手机Wi-Fi无线定位，分析实际废墟环境下Wi-Fi 2.4G无线信号的传播特性。通过对废墟结构的分析，使用矢量网络分析仪进行信道测量，对大尺度和小尺度衰减两种特性进行信道分析。采取理论预测和实际测量分析相结合的方法，对2008年5·12汶川地震的极重灾区遗址进行了废墟实地测量。对大尺度衰减进行路径损耗和钢筋混凝土吸收损耗分析，对小尺度衰减进行了平均超量时延和均方根时延分析，利用加窗、计算滑动均值，得到废墟下2.4G无线信号的传播规律，为下一步定位工作提供理论基础。 相似文献
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受多路径误差影响,GPS处于高反射环境下可导致接收机相位失锁,对点位坐标影响高达15cm;室内环境卫星无法锁定,GPS更是不能正常工作.本文引入了Skyhook XPS一体化混合定位系统,综合全球定位系统(GPS)、基站三角塔(Cell Tower Triangulation)和无线宽带(Wi-Fi)三种技术之优势,迅... 相似文献
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Summary The question of alternative technologies for high-speed Internet access lies at the heart of rural development problems. In
this paper, we focus on one of those technologies, the system combining satellite technologies and Wi-Fi. Based on an empirical
study carried out in three rural areas, we analyze the dynamics of the use and appropriation of that technology by the companies
and organizations participating in the experiment. Considered both from a technical and social standpoint, the technology
‘in use’ appears here in its structuring dimensions.
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| Valérie FautreroEmail: |
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