Stefan Nickel

Integrated Master Planning and Demand Fulfillment in Multi-Echelon Supply Chains: Partial vs. All-or-Nothing Fulfillment

Categories Applications - OR and Management Sciences, Network Optimization, Supply Chain Management Tags , , , ,

Modern supply chains differ in lead times, bottlenecks, and demand volatility. Advanced Planning Systems conventionally decouple Master Planning (MP) and Demand Fulfillment (DF) hierarchically, which improves tractability but ignores critical interdependencies between material availability, capacity utilization, and delivery promising. We propose an integrated MP‑DF model, formulate it as a Minimum‑Cost Multicommodity Flow (MCMCF) on a … Read more

On the Single-Multi-Commodity Gap: Lifting Single- to Multicommodity Flow Instances

Categories Applications - OR and Management Sciences, Linear Programming, Network Optimization Tags , , , , ,

Benchmark instances for multicommodity flow problems frequently lack the structural nuances of real-world networks or fail to maintain a rigorous mathematical relationship with their single-commodity counterparts. This paper introduces a formal meta-generation framework that addresses these limitations by lifting single-commodity minimum-cost flow instances into the multicommodity space while strictly preserving the underlying network topology, capacity … Read more

Modeling Multi-stage Decision Making under Incomplete and Uncertain Information

Categories Applications - OR and Management Sciences, Robust Optimization, Stochastic Programming Tags , , , ,

We propose a new universal framework for multi-stage decision making under limited information availability. It is developed as part of a larger research project which aims at providing analytical methods to compare and evaluate different models and algorithms for multi-stage decision making. In our setting, we have an open time horizon and limited information about … Read more