Exploring the Impact of Connectivity on Dissemination of Post Disaster Situational Data over DTN
Suman Bhattacharjee, Siuli Roy, Sukumar Ghosh, Sipra Das Bit · 2017
Opportunistic or Delay-tolerant networks (DTNs) may be used as a viable option for exchanging situational information during post-disaster communication in the absence of existing communication infrastructure. As opposed to traditional communication networks, situational information dissemination in DTNs depends on the degree of intermittent connectivity among the mobile nodes. Higher degree of connectivity implies smaller delay to disseminate situational information which results in better knowledge sharing. The degree of intermittent connectivity is influenced by mobility pattern of the nodes which is heterogeneous in nature. In this work, we attempt to formulate an empirical relationship between the degree of intermittent connectivity and extent of situational knowledge dissemination over DTNs in order to quantify the impact of the node mobility on the inter-shelter knowledge transfer In the absence of prior knowledge about the mobility patterns, we consider only the broad features of the impact. We introduce two metrics, Total Encounters and Knowledge Sharing Ratio. Total Encounters depends on node density, average movement speed of the nodes and elapsed time after initial node deployment. It serves as an indicator for estimating the degree of intermittent connectivity. The extent of situational information dissemination over an entire network is measured in terms of Knowledge Sharing Ratio. The relationship between Total Encounters and Knowledge Sharing Ratio is validated using the real mobility traces of volunteers captured from a field trial carried out in a disaster affected area. This analysis also helps us to formulate a suitable strategy for deployment of volunteer nodes in a post-disaster scenario.