FB 10 – Institut für Mathematik Algorithmische Algebra und Diskrete Mathematik Prof. Dr. Andreas Bley OBERSEMINAR ALGORITHMISCHE ALGEBRA UND DISKRETE MATHEMATIK Inventory Control: Multi-Echelon Optimization in a spare parts network Referent: Herr Christopher Grob (Externer Doktorand, Volkswagen AG) Termin: Dienstag, 12. April 2016, 17.15 Uhr Ort: Raum 1403, Heinrich-Plett-Str. 40, AVZ, Kassel-Oberzwehren Abstract: The Volkswagen After Sales network is supplying customers all over the world with spare parts for vehicles of the Volkswagen Group. Volkswagen wants to ensure customers get spare parts in a timely manner. The main challenge in this network is to cope with the stochastic and highly volatile demand. We consider the problem of optimizing the distribution of stock in a 2-level network with one central warehouse and n non-identical local warehouses, which order using an (R,Q)-policy. We assume that fill-rate targets and order quantities for each local warehouse are given, orders are fully backordered, partial deliveries are not allowed, and orders are served on a first come – first serve basis. Lead time is stochastic and lead time demand is assumed to follow a negative binomial distribution. Mean and variance of the wait time due to stock-outs at the central depot are approximated based on the Kiesmuller et al. (2004) method. gez. Prof. Dr. Andreas Bley The main challenge in this optimization problem is the computation of reorder points for given fill rate targets, which is computationally very expensive. In order to reduce the number of these function evaluations, we propose a method that adaptively refines two approximate models which under- and overestimate the actually needed stock at local warehouses. In each iteration we resolve and strengthen the corresponding integer linear programs in the proximity of the current approximate solution. Thus, we are able to give performance bounds for the exact problem and solve it even to optimality. We report on numerical results with real world data, which show the eﬀectiveness of this approach. Tee/Kaffee ab 16.45 Uhr im Raum 1404 Hierzu ergeht herzliche Einladung! gez. Prof. Dr. Andreas Bley