We analyse a single echelon single item inventory system where the demand and the lead time are stochastic. Demand is modelled as a compound Poisson process and the stock is controlled according to a continuous time order-up-to level policy. We propose a new method for determining the optimal order-up-to level for a cost oriented inventory systems where unfilled demands are backordered. The con...

In this paper, we study a production-inventory systems with finite production capacity and fixed setup costs. The demand process is modeled as a mixture of a compound Poisson process and a constant demand rate. For the backlog model we establish conditions on the holding and backlogging costs such that the average-cost optimal policy is of (s, S)-type. The method of proof is based on the reduct...

This paper tests the robustness of analytical results on performance measures for a production-inventory system with an unreliable production facility. A basic model is considered which involves a single production machine with constant production rate which operates as long as the accumulated inventory is below a pre-set threshold, and is idle otherwise. The demand process follows a compound P...

Emergency orders have shorter lead times but incur extra costs compared to normal orders. We present a discrete-time Markov decision model where normal orders are issued according to a reorder point policy with a fixed order quantity, whereas emergency orders are controlled by a state-dependent reorder point policy with a target stock level. A rapid policy iteration algorithm is used to find an...

We consider a liquid type of a deteriorating item which is packaged by an outside supplier and is delivered to final customers by a distributor. Customers arrive according to a Poisson process and ask for an integer number of packages. Unsatisfied demands are backordered. The inventory is reviewed continuously and replenished from an external supplier with a positive deterministic lead time fol...

Tourism is a sector that contributes to the economic development of both developed and developing countries, with this structure, it contains environmental, social, dimensions sustainable development. This study aims estimate effects environmental quality other determinants on international tourism demand. Within scope 2008–2017 period, demand from 27 different countries top 10 attract most tou...

Many kinds of reorder point reorder quantity policies with an emergency order, in which we can decide when the expedited order point is reached and then we place an expedited replenishment order, have been presented in earlier contributions. Very few studies on cyclic inventory control with an emergency order, however, have been reported. The purpose of this paper is to establish some analytica...

Little’s law allows to express the mean user throughput in any region of the network as the ratio of the mean traffic demand to the steady-state mean number of users in this region. Corresponding statistics are usually collected in operational networks for each cell. Using ergodic arguments and Palm theoretic formalism, we show that the global mean user throughput in the network is equal to the...