Two-stage Optimization Approach for the Problem of Grain Dispatching and Transportation
The problem of grain dispatching and transportation is a vehicle routing problem.This paper presents a two-stage optimization algorithm for solving the problem.In the first stage,all the feasible routes are generated by means of a graph-search algorithm.The search tree is pruned according to the constraints.In the second stage,an integer programming model is designed to select the optimum routes from the set of feasible routes.The total cost of all the optimum routes is the least.Based on the two-stage approach,a decision support system for grain dispatching and transportation was also developed.The system was tested with a set of real instances.And in a worst-case scenario, the routes obtained ranged from a 9% to 15% reduction in the distance and from a 10% to 18% reduction in operational costs.