Multi-item imperfect production lot size model with hybrid number cost parameters

In this study we have developed a multi-item finite production lot size model with reworking of imperfect quality items. When production stops, defected items are assumed to rework at a constant rate. The cost parameters in this model are taken here as hybrid numbers (i.e. some of the costs are fuzzy numbers as well as random variables). Then the model is converted into a multi-objective geometric programming (GP) problem. A numerical example is given to support the problem. A sensitivity analysis has given to study the nature of the objective functions.