Robust and Large Scale Distributed Disaster Information System over Internet and Japan Gigabit Network

In this paper, a robust and large scale resident-oriented safety information system on the occurrence of the various disasters constructed over a nationwide high-speed network is introduced. The evacuated residents can register their safety information to the local safety information servers in the evacuation area whether they can safely evaluated or not using mobile PCs or terminals at the evacuation place or mobile terminals on the way of evacuation. All of the local information servers are connected each other by wireless network and the safety information can be sent an upper-layer database in the district area and finally integrated into a district safety information in that region. In our system some of the damaged local servers due to the disaster can be detected and recovered by the upper- layer database server. On the other hand, the upper-layer database servers are backed up by mirror servers located at mutually different locations with long distance to isolate the influence of the same disaster when the some of them were destroyed or disordered. Thus, by introducing two levels of redundancy and backup functions, more large scale and robust safety information database system can be realized.