This paper introduces a variant of the well-known Multi-Depot Periodic Vehicle Routing Problem, which is inspired by a real situation of a distribution company. The problem consists in determining the number of extra vehicles to rent, the assignment of vehicles to plants, and the routes between plants and distribution centers, while the transportation cost is minimized. We propose a mixed integer linear formulation and a Reactive Greedy Randomized Adaptive Search Procedure to solve the problem. Extensive computational results show that the proposed procedure provides high-quality solutions with an average gap lower than 2.5% from the computed lower bound.

In this work, we introduce a Flexible Job-shop Scheduling Problem with Resource Recovery Constraints (FRRC). In the FRRC, besides the constraints of the classical Flexible Job-shop Scheduling Problem (FJSP), operations may require resources to be processed. The resources are available in batches and a recovery time is required between each batch. This problem is inspired by a real situation faced by a brewing company where different yeasts are available in a limited quantity and are recovered only once they have been completely used. The objective is to schedule the operations such that the makespan is minimised. A mathematical model and a metaheuristic based on a General Variable Neighborhood Search is proposed for the solution of the FRRC. Computational results over a large set of instances, adapted from the FJSP literature, are presented.