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

518-529India is vulnerable to disasters such as earthquakes, floods, tsunamis, landslides forest fires and cyclones due to its unique socio-economic 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

Formal Verification of Receiver Initiated Load Distribution Protocol with Fault Tolerance and Recovery using Event-B

1078-1090Load distribution is a process that involves the allocation of tasks to various nodes in the distributed system in such a manner that overall resource utilization is maximized, and overall response time is minimized. This paper presents a formal model for verification of receiver-initiated load balancing and fault tolerance protocol with recovery in distributed systems using the eclipse-based Event-B platform called Rodin. Here, the receiver-initiated load balancing approach is demonstrated along with tolerance of node failure and recovery. In this approach, an underloaded node (receiver) initiates the process of load transfer from an overloaded node (sender). The underloaded node broadcasts a request message to obtain load from the overloaded nodes. The overloaded nodes reply with their load value. The underloaded node then selects the optimal overloaded node for load transfer. The chances of node failure are minimized by reducing the number of overloaded nodes. The process of recovery from failure is also shown in the proposed model. Formal methods are used to mathematically verify the critical properties of the system by developing a model based on its specifications. Our objective is to verify and validate the model for correctness through discharge of proof obligations using Event-B. Event-B is a formal method which is used for verification of a model based on distributed systems. The proof obligations generated by the model are discharged which ensures the correctness of our model

A composition mechanism for refinement-based methods

Event-B developments are mostly structured around the refinement relationship. This top-down development architecture enables system details to be gradually introduced into the formal model. However, this results in large models with monolithic structures. We develop a composition mechanism allowing to develop models bottom-up. In particular, our proposed mechanism works seamlessly with the existing refinement technique in Event-B. As a result we have built a formal development method that can take advantage of both top-down and bottom-up approaches. We prove the correctness of machine inclusion with refinement using the supporting Rodin platform

Development of a System Controlling Cars on a Bridge using Machine Inclusion

This dataset is associated with the following paper: Thai Son Hoang, Dana Dghaym, Colin Snook, and Michael Butler. A Composition Mechanism for Refinement-Based Methods. In Zhenjiang Hu and Guangdong Bai, editors, *ICECCS&#39;17: International Conference on Engineering of Complex Computer Systems, Fukuoka, Japan, November 5--8, Proceedings*, IEEE, 2017. Details about the dataset can be found in the README.md file.</span