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PREDATOR - PREY MODEL FOR DISCRETE SENSOR PLACEMENT

A metaheuristic approach is proposed to design the optimal placement of monitoring stations, for aiming an early detection of the intentional water distribution networks contamination. The approach is based on the use of a predator-prey model, that is applied to multi-objective optimization. The proposed algorithm is used to solve the sensor constrained contamination detection problem, which is polynomially equivalent to the asymmetric k-center problem, so it is NP-Hard In particular the predator-prey model is applied to find the optimal sensors placement evaluated, according to the four design objectives which are described in the Battle of Water Sensor Networks (BWSN) manifesto. Both predators and preys are subjected to an evolution process. The competing coevolution approach has been chosen to avoid the problem of designing the fitness function or, in other words, to avoid the problem of locating the most representative contamination events. The candidate solutions and tests, which are used to evaluate these solutions, evolve simultaneously to find the optimal evaluation set, and as a consequence to minimize the number of needed checks, during the selection of the optimal solution.