A MULTI-OBJECTIVE GENETIC ALGORITHM FOR THE PASSENGER MARITIME TRANSPORTATION PROBLEM

Over the last years, the transportation demand has continuously increased and a further growth is predicted for the next future especially as regards the maritime sector. As a consequence, shipping companies will be asked to improve the supplied services in order to assure a high quality and time-effective goods and passengers transportation, deriving at the same time their own benefits by minimizing costs. Therefore, the optimization of routes and schedules together with the fleet deployment take a meaningful role on companies profitability and efficiency. In such a perspective, the present paper proposes a multi-objective mathematical programming model to determine a set of routes and schedules that allows at satisfying the passenger movement requests, contemporary minimizing both the total transportation cost and the passenger dissatisfaction. The real context which the present paper is focused on is that of a shipping company forced by the Regional Authority and the Government to supply the service in order to assure the territorial continuity. As a consequence, all routes need to be supplied even if unprofitable. As regards the resolution approach, a multi-objective Genetic Algorithm (GA) is proposed. The main innovative aspect of the proposed GA is the way the solution is articulated since it consists of several sub-chromosomes of different length each one representing the route sailed by a specific vessel. Furthermore, each route is developed so that each seaport can be reached even more than once within the same route, namely sub-cycles are here allowed. Finally, the case study results are reported.