Rigorous Design of Fault Tolerance and Recovery Algorithm for Disaster Management and Relief Distribution System using Event-B

India is vulnerable to disasters such as earthquakes, floods, tsunamis, landslides forest fires and cyclones due to its unique socioeconomic and geo-climatic conditions. Twenty seven out of thirty-six states and union territories are prone to different types of disasters which cause loss of life, disruption of livelihoods, damage to infrastructure and property which in turn becomes a heavy burden on the national economy. Effective management of relief work is a key step towards normalizing human life post disaster. In this paper, we have presented the formal development and verification of a fault tolerance and recovery algorithm for district level disaster control centers in India which are connected to each other via a communication network. Formal methods help in the verification of critical properties of complex systems by developing mathematical models so that design errors can be detected and removed during the early stages of software development. Event-B, which is a formal method and Rodin platform is used for this work. Event-B is a mathematical language of first-order logic to provide a solution to the complex algorithms formally. In this algorithm a Disaster Control Centre is chosen as the coordinator based on its unique vote value. This vote value is allotted and modified dynamically based on the extent of damage in the area where the center is located. The center having the highest vote value among the currently active centers is elected as the coordinator. The correctness of the algorithm is verified through discharge of proof obligations generated by the Event-B model.