We consider a two-echelon assembly system producing a single final product for which the demand is known. The first echelon consists of several parallel stages, whereas the second echelon consists of a single assembly stage. We assume that the yield at each stage is random and that demand needs to be satisfied in its entirety; thus, several production runs may be required. A production policy s...

In this paper, we study a multi-echelon uncapacitated lot-sizing problem in series (mULS), where the output of the intermediate echelons has its own external demand, and is also an input to the next echelon. We propose a polynomial-time dynamic programming algorithm, which gives a tight, compact extended formulation for the two echelon case (2-ULS). Next, we present a family of valid inequaliti...

Given the emergence of two-echelon distribution systems in several practical contexts, this paper tackles, at strategic level, a network design problem under uncertainty. This is defined as stochastic multi-period capacitated location-routing (2E-SM-CLRP). It considers partitioned into two echelons: each echelon involves specific location-assignment-transportation schema that must cope with fut...

T paper studies a periodic-review, serial supply chain in which materials are ordered and shipped according to R nQ policies. Three information scenarios are considered, depending on the level of information available: echelon, local, and quasilocal. In the echelon scenario, each stage can access the inventory and cost information within its echelon (comprising the stage itself and all downstre...

This paper presents a two-echelon non-repairable spare parts inventory system that consists of one warehouse and m identical retailers and implements the reorder point, order quantity (R, Q) inventory policy. We formulate the policy decision problem in order to minimize the total annual inventory investment subject to average annual ordering frequency and expected number of backorder constraint...

A stream is a continuous version of a supply chain. It is like a series inventory system, but stock can be held at any point along a continuum, not just at discrete stages. We assume stationary parameters and aim to minimize the long-run average total cost. We show that a stationary continuous-stage echelon base-stock policy is optimal. That is, at each geographic point along the supply stream,...

We study a two echelon supply chain with AR(1) demand and unit replenishment lead-times. Each echelon of the supply chain uses conditional expectation to generate MMSE forecasts. Both echelons use these forecasts inside the “Order-Up-To” policy to generate replenishment orders. We investigate 3 different scenarios: The first is when each echelon aims to minimize their own inventory holding and ...