Lot - sizing and scheduling in flow shops

Abstract

Lot-sizing is concerned with the product quantities, whereas scheduling considers the specific machines and product sequences. Lot-sizing and scheduling refers to pro cedures that aim to solve these interdependent problems simultaneously. In this thesis, we investigate three lot-sizing and scheduling problems encountered in flow shops. The first one is a single-level parallel machine problem with a secondary resource and cumu lative demand, where the objective is to minimize the number of setups and teardowns. The second examines a two-machine flow shop with a serial bill-of-materials. The goal is to first minimize back orders and then the number of changeovers. The third prob lem arises in the two-machine flow shop as well. The question is whether there exists a feasible production plan to satisfy all requirements. For the first two problems, we sug gest reformulations, prove several optimality conditions, and carry out computational experiments. For the last one, we develop a polynomial algorithm after giving some theoretical results.