GSFord: Towards a Reliable Geo-social Notification System

The eventual goal of any notification system is to deliver appropriate messages to all relevant recipients with very high reliability in a timely manner. In particular, we focus on notification in extreme situations (e.g. disasters) where geographically correlated failures hinder the ability to reach recipients inside the corresponding failed region. In this paper, we present GSFord, a reliable geo-social notification system that is aware of (a) the geographies in which the message needs to be disseminated and (b) the social network characteristics of the intended recipient, in order to maximize/increase the coverage and reliability. GSFord builds robust geo-aware P2P overlays to provide efficient location-based message delivery and reliable storage of geo-social information of recipients. When an event occurs, GSFord is able to efficiently deliver the message to recipients who are either (a) located in the event area or (b) socially correlated to the event (e.g. relatives/friends of those who are impacted by an event). Furthermore, GSFord leverages the geo-social information to trigger a social diffusion process, which operates through out-of band channels such as phone calls and human contacts, in order to reach recipients which are isolated in the failed region. Through extensive evaluations, we show that GSFord is reliable, the social diffusion process enhanced by GSFord reaches up to 99.9\% of desired recipients even under massive geographically correlated regional failures. We also show that GSFord is efficient even under skewed distribution of user populations.