In this paper, we consider numerous inventory control problems for which the base-stock policies are known to be optimal and we propose stochastic approximation methods to compute the optimal base-stock levels. The existing stochastic approximation methods in the literature guarantee that their iterates converge, but not necessarily to the optimal base-stock levels. In contrast, we prove that t...

Variability, in general, has a deteriorating effect on the performance of stochastic inventory systems. In particular, previous results indicate that demand variability causes a performance degradation in terms of inventory related costs when production capacity is unlimited. In order to investigate the effects of demand variability in capacitated production settings, we analyse a make-to-stock...

We study a class of two echelon, serial systems with identical ordering capacities or limits for both echelons. For the case where the lead time to the upstream echelon is one period, the optimality of state-dependent, modified echelon base-stock policies is proved using a decomposition approach. For the case where the upstream lead time is two periods, we introduce a new class of policies call...

We consider a serial production system controlled by the base-stock policy, in which customer demands must be satisfied immediately or it will be considered lost. Since the exact analysis is impossible for the general system,we present a phase-type approximation for a base-stock controlled serial production system. The numerical results indicate that this approximation provides good estimates f...

The review focuses on applications of artificial neural networks (ANNs) in various subsystems of pulp and paper making processes. Some applications are pertinent to modeling of pulping, bleaching and energy conservation process while others are related to control of refining, washing of brown stock, combustion of black liquor, lime kiln operation, grade changes and quality control. A general al...

Fine grinding mills have improved in design and efficiency in recent years, allowing major opportunities for treatment of materials where liberation to grind sizes below fifteen microns are required. The successful development of the IsaMill, a horizontal stirred mill, has produced equipment capable of grinding the larger tonnages which exist in mineral processing operations, to product sizes b...

We study a multicomponent, multiproduct production and inventory system in which individual components are made to stock but final products are assembled to customer orders. Each component is produced by an independent production facility with finite capacity, and the component inventory is controlled by an independent base-stock policy. For any given base-stock policy, we derive the key perfor...

We consider two reverse logistics systems where returned products are as good as new. For the first system, the product return flow is independent of the demand flow.We prove that the optimal policy is of base-stock type and we establish monotonicity results for the optimal base-stock levels, with respect to the system parameters (arrival rate, production rate, return rate, production cost, los...

We consider a single item assembled from two components. One of the components has a long leadtime, high holding cost and short review period as compared to the other one. We assume that net stocks are reviewed periodically, customer demand is stochastic and unsatisfied demand is back ordered. We analyze the system under two different policies and show how to determine the policy parameters min...