On Interactions between Evacuation Behavior and Information Dissemination via Heterogeneous DTN

Abstract

Disaster information-sharing among emergency personnel and residents helps facilitate quick and safe evacuation from disaster areas. However, it is difficult to communicate with people in disaster areas when communications infrastructure is not available. To tackle this problem, we have been developing a heterogeneous delay/disruption tolerant network (DTN)-based disaster information-sharing system that uses long-range narrowband links (e.g., LoRa) and short-range broadband links (e.g., Wi-Fi). Our disaster information-sharing system disseminates evacuation recommendations, evacuation routes, and other vital information to residents in disaster-stricken areas by the store-carry-forward method using residents' mobile devices and relay nodes installed at roadsides, fire departments, and shelters. Since evacuee movements and information dissemination in heterogeneous DTN affect each other, and since understanding those interactions will facilitate the development of more efficient disaster information distribution strategies, we developed a simple cellular-automaton-based simulation model to investigate data dissemination in our heterogeneous-DTN system and analyzed those interactions. Our simulation results revealed a particular complication that we have named the "leaving-behind phenomenon," in which people who have obtained information on damaged roads take detours to a shelter before providing the same information to the evacuees that will approach the damaged road. Based on our simulation results, we report on a way to alleviate this problem by installing fixed relay nodes at the most suitable locations.