| The aftermath of a natural disaster is typically characterized by lack of a reliable medium for dissemination of information to survivors. Current state-of-the-art emergency response systems rely on satellite radio-enabled devices, but survivors, unlike first responders, do not have access to such devices. To mitigate this problem, we present PERPETUU a solar-powered portable GIS microserver. The microserver node can be deployed in a disaster scene, and can serve maps to survivors viewable on browsers of off-the-shelf mobile systems. A key innovation in the design of the PERPETUU node is a multi-tiered hardware architecture-the system combines a low-power micro-controller, a medium-power Wifi module, and a high-power micro-processor to provide large spectrum of power states. In addition to being able to detect survivors using a low-power Wi-Fi sensing technique, the tiered design leverages hardware-assisted energy measurements, a wakeup controller to balance energy harvested from solar panels with energy consumed by the system, and a future-energy prediction algorithm, in order to provide natural disaster survivors with up-to-date emergency relief information. We evaluate PERPETUU using measurements from our prototype and trace-based simulations, and show that it can function near perpetually while serving GIS maps and other information to a large number of survivors. |
