Non-stationary stochastic lot sizing problem appears in many industrial environments where demand is nonstationary and stochastic, and replenishments require fixed freight fees. This paper presents the cost performance assessment of three inventory control strategies proposed for the stochastic lot sizing problem, namely Hua et al. (2008)’s strategy (HYHX), Tarim and Kingsman (2006)’s model (TK...

Motivated by the challenges encountered in sawmill production planning, we study a multi-product, multi-period production planning problem with uncertainty in the quality of raw materials and consequently in processes yields, as well as uncertainty in products demands. As demand and yield own different uncertain natures, they are modeled separately and then integrated. Demand uncertainty is con...

A newly developed low cost system for fish-farm wastewater treatment was evaluated. The system consisted two major parts: (1) a new type of square tank design with two separate outlets, i.e. one centrally positioned high solids concentration outlet and one corner located low solids concentration primary outlet; and (2) a stationary bowed screen for solid removal from the high solids effluent. R...

In this paper we study the capacity investment decision for make-to-order manufacturing firms that utilize a fixed capacity, operate in a stochastic, stationary market, and can influence their demand rate by increasing or decreasing their sales effort. We consider manufacturing situations that differ in sales contribution, in market elasticity to sales effort, work-in-process costs, and demand ...

This paper is motivated by the inventory planning issues faced by a manufacturer of a digital projector. The seller faces demand from two sources: new demand, and demand to replace failed items under warranty. We model this setting as a multi-period single product inventory problem where the new demand in different periods are independent and the demand for replacing failed items under warranty...

We demonstrate the possibility of optimal control of physical inventory systems in a nonstationary fitness terrain, based on the combined application of evolutionary search and adaptive critic terrain following. We show that adaptive critic based approximate dynamic programming techniques based on plant-controller Jacobeans can be used with systems characterized by discrete valued states and co...

We consider a firm that faces random demand and receives product from a single supplier who faces random supply. The supplier’s availability may be affected by events such as storms, strikes, machine breakdowns, and congestion due to orders from its other customers. In our model, we consider a dynamic environment: the probability of disruption, as well as the demand intensity, can be time depen...