A Study of Optimization of IDDD (Information Delivery System for Deaf People in a Major Disaster)

In this paper, we describe the optimization of our prototype information delivery system (IDDD) designed for deaf people encountering major disasters for a scheduled trial in 2013, based on problems detected in a preliminary trial experiment. The two major problems that need to be addressed for the optimal design of IDDD are the delay of sending messages from the server, and the flexible maintenance of connections between LED displays, especially in emergency situations. Firstly, we compare performance between two information delivery methods (SMS and GCM) in detail. We conclude that GCM is better than SMS from the viewpoints of delay and stability. Next, we evaluated performance of OLSR from the viewpoint of quick route change, which is necessary to establish connection between devices. We conclude that ad hoc network performance using OLSR is better than implantation of last year using AODV for the purpose of our system. As a result of our analysis, we explain how to enhance IDDD for our planned trial in 2013.