We provide a review of the types of equilibria typically found in operations management inventory papers and a discussion on when the commonly used stationary infinite-horizon (open-loop) equilibrium may be sufficient for study. We focus particularly on order-up-to and basestock equilibria in the context of inventory duopolies. We give conditions under which the stationary infinite-horizon equi...

Characterization and evaluation of a biological submerged filter was carried out on a full-scale pilot plant performing removal of biochemical oxygen demand (BOD) and total nitrogen (TN) from pre-treated urban wastewater. The average influent values of BOD5, chemical oxygen demand (COD) and TN were 370, 1,015 and 60 mg/L, respectively. The pilot plant produced good discharge quality during stea...

As the requirement of task is dynamical, the usage of equipment will change with time and it will result in the fluctuating demand for spare parts all over the time. In order to improve equipment performance, the users need to forecast equipment failure frequency and demand for spare parts within the task period. Demand in a moment of task period is the result of cumulative effect of the failur...

In this paper we consider a periodic review order-up-to inventory system with capacitated replenishments, lost sales and zero lead time. We consider discrete demand. It is shown that the initial stock levels of the different review periods form aMarkov chain andwe determine the transitionmatrix. Furthermore we study for what probabilitymass functions of the review period demand theMarkov chain ...

This paper presents an analytical model for computing the stationary distribution of the on-hand inventory in a continuous-review inventory system with compound Poisson demand, Erlang distributed lead time, and lost sales, where the supplier can assume one of the two “available” and “unavailable” states at any point in time according to a continuous-time Markov chain. Exact analytical expressio...

In this paper we investigate the complexity of the economic lot-sizing problem with remanufacturing (ELSR) options. Whereas in the classical economic lot-sizing problem demand can only be satisfied by production, in the ELSR problem demand can also be satisfied by remanufacturing returned items. Although the ELSR problem can be solved efficiently for some special cases, we show that the problem...

In this paper a demand time series is analysed to support Make-To-Stock (MTS) and Make-To-Order (MTO) production decisions. Using a purely MTS production strategy based on the given demand can lead to unnecessarily high inventory levels thus it is necessary to identify likely MTO episodes. This research proposes a novel outlier detection algorithm based on special density measures. We divide th...

This paper addresses the single-item, non-stationary stochastic demand inventory control problem under the nonstationary (R,S) policy. In non-stationary (R,S) policies two sets of control parameters—the review intervals, which are not necessarily equal, and the order-up-to-levels for replenishment periods—are fixed at the beginning of the planning horizon to minimize the expected total cost. It...

Many studies have estimated the aggregate import demand function for Pakistan by using non-stationary data. Their findings suffer from the so-called ‘spurious regression’ problem. This study attempts to estimate the aggregate import demand function for Pakistan by employing Johansen and Juselius cointegration technique on the annual data for the period 1975-2005. Our results show that there is ...