Research seminar: Simon Emde

Title: Thawing the Warehouse: Dynamic Replenishment in Modern Fulfillment.

Speaker: Simon Emde, Professor - Chair of Information Systems, esp. Business Intelligence, Friedrich Schiller University Jena, Germany, Prof. Dr. Simon Emde | Wirtschaftsinformatik, insb. Business Intelligence.

Abstract: Depalletization planning represents a critical operational bottleneck in partially automated wholesale warehouses, where fast-picking forward buffers are continuously restocked from high-bay pallet reserves under uncertain order sequences and tight storage capacities. While the traditional forward-reserve literature predominantly addresses static or deterministic configurations, this work introduces the Stochastic Depalletization Problem (SDP), formalizing forward buffer replenishment as a dynamic Markov decision process aimed at minimizing total depalletization penalties. We prove that even the deterministic depalletization problem (DDP) is NP-hard, establishing the necessity for efficient approximation methods in real-time environments. To resolve this, we develop a Multiple-Scenario Approach (MSA) using mixed-integer linear programming (MILP) alongside a fast Empirical Frequency Heuristic (EFH) that captures anticipated SKU frequencies across sampled demand trajectories without solving mathematical programs. Evaluated on an 80-day dataset comprising over 1.2 million picks across more than 24,000 SKUs from a major European retailer, EFH finds solutions in milliseconds while reducing depalletization events by up to 70% relative to industrial practice. Furthermore, our findings demonstrate that the rigid "frozen zones" conventionally enforced to guarantee short-term demand certainty are unnecessary under effective look-ahead policies, enabling higher forward-area space utilization and significantly faster customer order fulfillment without capital-intensive infrastructure changes.

Host: Sanne.

Simon Emde will visit our department for three days. If you are interested in a meeting with Simon during his visit, please reach out to Sanne or directly to Simon.