Multicriteria analysis for an aggregate planning production model

This paper presents a mixed integer multiple objective linear programming model in the branch of the aggregate production planning applied to a Portuguese firm producing construction materials. The multiple objective model was developed with the following objectives in mind: (1) to maximise profit; (2) to minimise back orders; (3) to minimise workforce fluctuations. This model allows the inclusion of certain aspects related to the partial inflexibility of the workforce, legal restrictions on the workload, workforce size (workers to be hired and downsized), workers in training, limitation of production and inventory levels, and the quantity of products to be subcontracted. The purpose of this study is to define the level and type of workers, the amount of regular hours and overtime, the inventory level for each type of product, and the level of subcontracted products in order to meet the forecast demand, for a planning period of 12 months. Also presented is an interactive method, which provides support for the decision-maker in knowledge and exploitation of the possible solutions and in selection of the ‘best solution’.