A labour-constrained model for aggregate production planning

In today's business environment where workers' participation and teamwork h ave been widely adopted, it is not desirable to employ a layoff and hiring strategy to solve the problems of changing demand because of its negative i mpact on job security and workers' moral. In this paper, an aggregate produ ction planning model that considers the level of employment as a constant o ver time is constructed. In addition to deriving the model mathematically, actual data from a Portuguese building material company are used to demonst rate the implementation of such a model. The solution provided by the model could reduce the total relevant cost of the company by as much as 8.1%.