This paper considers an inventory system responsible for repairable equipments located at several operational sites, each in different area. When a failure occurs at the operational site, spare parts are required. We analyze a multiple-supplier inventory system that includes an internal repair shop that offers several modes of repair with different repair times and an external supplier of spare...

The advent of e-commerce has prompted many manufacturers to redesign their traditionalchannel structure by engaging in direct sales. In this paper, we present a dual channel inventory modelbased on queuing theory in a manufacturer-retailer supply chain, consisting of a traditional retailchannel and a direct channel which stocks are kept in both upper and lower echelon. The systemreceives stocha...

In this paper, we consider a supply chain model consisting of a single product, one supplier and multiple retailers. Demand at the retailers is random, but stationary. Each retailer places her orders to the supplier according to the well known (Q,R) policy. We assume that the supplier has on-line information about the demand as well as inventory activities of the product at each retailer and em...

We show the optimality of state dependent echelon base stock policies in uncapacitated serial inventory systems with Markov modulated demand and Markov modulated stochastic leadtimes in the absence of order crossing. Our results cover finite time horizon problems as well as infinite time horizon formulations, with either a discounted or an average cost criterion. We employ a novel approach, bas...

Starting in the 1960s, a number of academic works have focused in serial and distributed multi-echelon structures and in both deterministic and stochastic environments. Clark and Scarf (1960, 1962) developed a seminal work in which they presented optimal policies for a serial multi-echelon system. Schwartz (1973) studied a deterministic model having one warehouse and N retailers and showed that...