we present an improved implementation of the wagner-whitin algorithm for economic lot-sizing problems based on the planning-horizon theorem and the economic- part-period concept. the proposed method of this paper reduces the burden of the computations significantly in two different cases. we first assume there is no backlogging and inventory holding and set-up costs are fixed. the second model ...

This paper presents a new mathematical model for a bi-objective job shop scheduling problem with sequence-dependent setup times that minimizes the weighted mean completion time and the weighted mean tardiness time. For solving this multi-objective model, we develop a fuzzy multi-objective linear programming (FMOLP) model. In this problem, a proposed FMOLP method is applied with respect to the o...

In this paper, we develop a procedure for selecting a supplier. Suppliers are characterized by their lead time, price and quality (random yield). Each purchased item is acceptable with a given probability and independent of the others. We assume the demands are deterministic with no set-up cost and backordering is allowed. For each supplier, an optimal ordering policy is developed. We prove the...