Making better use of smartphone networks during disasters

ETH professor Dirk Helbing is convinced that digital tools offer ways in which to minimise the impact of a disaster. “We often hear that digital platforms from Silicon Valley are undermining social values,” he says. “It’s important to remember, however, that digitalisation can also be used to reinforce precisely these values.” These social digital technologies were studied in the research initiative “Engineering Social Technologies for a Responsible Digital Future” at Delft University of Technology (TU Delft) led by Helbing.

A new study from this initiative was published in the journal Scientific Reports at the end of March; it indicates that we fare better in a crisis if we take a cooperative approach, says Helbing. “And not just from compassion, but because sharing in a crisis situation is a prerequisite for survival in general.”

The specific point of this study was how communication can function better – and longer – in a disaster. Experience with severe natural disasters, such as Hurricane Katrina in the US (2005) and the earthquake in Japan (2011), showed that people are often left to fend for themselves in the first few hours after the event. A disrupted infrastructure generally means that they are cut off from any form of communication, making it difficult for them to help each other. But it is precisely this period directly following a disaster that is essential, as it takes time for the emergency services to arrive and the chances of survival fall as each hour passes. The first 72 hours are considered critical, because this is the period in which the most lives can be saved.

The network remains stable for longer

The study led by Helbing together with Frances Brazier and Martijn Warnier of TU Delft aims to help deal with such emergency situations. It suggests an app that establishes a communications network between mobile phones and makes optimal use of the battery charge remaining in the disaster area. In their paper, the researchers highlight the functions this app must have in order to keep the network stable and the individual devices connected to each other for as long as possible.

This approach works by ensuring that devices with a high battery charge function as hubs. These mobiles are then used to run communications processes that consume significant amounts of energy, i.e. use up the battery. This was simulated in the study through sending text messages. Devices with little battery charge are mostly “spared”, thus minimising the number of devices that drop out of the network – the more mobile phones that remain in the network, the more stable it is. The system proposed by the scientists continuously optimises itself: if a device used as a hub becomes low on battery, it is automatically replaced by another with more battery charge.

These functions enable people to stay in touch and help each other for longer. The research group has named this new emergency communication system SOS (Self-Organisation for Survival). Simulations enabled the group to demonstrate how the new method is indeed more effective – with conventional “mesh” networks only 18 percent of all mobile phones remain in the network after 24 hours; with the SOS system, this figure rises to 99 percent. And following the critical period of 72 hours, the majority of mobiles (62 percent) were still active.

The key advantage of the SOS system is that the energy in the network is used more evenly, i.e. more fairly. “And everyone benefits from this fair distribution,” says doctoral student Indushree Banerjee, the study’s lead author. Helbing adds: “A community needs to be able to communicate in order to organise itself. When batteries run out, everyone suffers as a result of gaps in the communications network.”

Decentralised solutions for a disaster situation

According to Helbing, the study will help communities to help themselves: “People are highly motivated to help others in the event of a crisis, but this help needs to be coordinated if it is to be effective.” When a disaster occurs, normally countless calls are made to a central point, which is then overwhelmed as a result. This is why a decentralised solution such as the SOS system is useful in the event of a disaster situation by helping to improve “participatory resilience”, i.e. the ability to withstand a crisis by means of participation.

The development of the SOS method is one of a series of proposals on how digital tools can help in emergency situations. It originated with a hackathon on earthquake resilience with the research and innovation network Swissnex, in which three solutions stood out in particular in San Francisco (see video): those affected by a disaster were able to create a map of the damage using the “Amigo Cloud” app, while the “Helping Hands” app enabled them to tell neighbours what kind of help they needed. The third solution, the “Charge Beacon” initiative, proposed seating areas with solar roofs, so smartphones could be charged in emergency situations without a power grid. This extra energy would make it possible to use other functions in addition to text messages in the critical period following a disaster.

Helbing believes that experience with Covid-19 has highlighted the urgency with which the issue of participatory resilience should be addressed by authorities: “It’s too late to develop the apps after the crisis has already happened.” Specifically, it is now a question of implementing the SOS system devised by the researchers in a software program and integrating it into emergency apps – for example, says Helbing, expanding the functionality of the “AlertSuisse” app from the Federal Office for Civil Protection.