Bir (Yeniden) sipariş-üzerine-montaj sisteminde geri dönen ürünlerin parça tahsisi ve risk-ayarlı birleşik temel-stok seviyesi optimizasyonu

In this study, we consider a multi-component, multi-product, periodic-review (re) assemble-to-order system (ATO) that uses an independent base-stock policy for inventory replenishment of the components. At the beginning of each period, end-of-lease used products (also called returns or cores) are returned. Because the quality of cores is random, they are tested, sorted and graded into four pre-specified quality levels. Then, the random, jointly and continuously distributed demands for the products are realized. In our problem, partial fulfillment is not allowed. The system quotes a predetermined response time window for each product, and it penalizes if the demand is not satisfied within this time window. We model this problem through a risk-averse, two-stage stochastic programming problem, where the first-stage decisions are the base-stock levels for all components, and the second-stage decisions are the allocations of components to different products. The risk adjustment is formulated through a chance constraint, which is then replaced by a conditional value-at-risk (CVaR) constraint. We assume that the joint distribution of the random data is known, so we approximate the problem through its sample average approximation (SAA), and we solve this approximation through the L-shaped method. We further analyze the validity of our results and present some encouraging numerical results.