This work reports on the development details and results of an experimental setup for the localization of the attendants of a music festival. The application had to be reporting in real-time the asymmetric crowd density based on the Received Signal Strength Indicator (RSSI) between the attendants’ smartphones and an experimental installation of 24 WiFi access points. The impermanent nature of the application led to the implementation of a cloud-based solution, called “STRAND”. STRAND is based on Node.js components, which communicate through websockets, collect, process and exchange data and continuously report the produced information to the end-user. To cope with the near real-time requirements, and the volatility of the crowd concentration density, STRAND horizontally scales the trilateration component, i.e. the component that estimates the user location based on distance measurements. STRAND was tested during the festival days in July 2018 and the results show a system that copes with very high loads and achieves the temporal and accuracy requirements the were set.

中文翻译：

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Strand：使用Node.js进行可扩展的三边测量

这项工作报告了音乐节参加者本地化的开发细节和实验设置的结果。该应用程序必须根据服务员的智能手机之间的接收信号强度指示器（RSSI）以及24个WiFi接入点的实验安装情况，实时报告不对称人群密度。该应用程序的无常性质导致了基于云的解决方案的实施，该解决方案称为“ STRAND”。STRAND基于Node.js组件，这些组件通过Web套接字进行通信，收集，处理和交换数据，并不断将产生的信息报告给最终用户。为了满足近乎实时的要求以及人群集中密度的波动性，STRAND水平缩放了三边测量分量，即 根据距离测量值估算用户位置的组件。STRAND在2018年7月的节日期间进行了测试，结果表明该系统可以应对非常高的负载并达到设定的时间和精度要求。