Over the summer period, two new papers on the two-echelon inventory-routing problem have been published (with Sara Charaf as the lead author and joint work with Duygu Tas and Simme Douwe Flapper):
Charaf, S., Tas, D., Flapper, S. D. P., & van Woensel, T., A Matheuristic for the Two-Echelon Inventory-Routing Problem. Computers & Operations Research.
Charaf, S., Flapper, S. D. P., Tas, D., & van Woensel, T., A Branch-and-Price Algorithm for the Two-Echelon Inventory-Routing Problem. Computers & Industrial Engineering.
The two papers focus on innovative approaches to solving the two-echelon inventory-routing problem (2E-IRP), essential for optimizing supply chain operations under a vendor-managed inventory system.
The first paper, “A Matheuristic for the Two-Echelon Inventory-Routing Problem,” introduces a two-phase matheuristic approach that combines tabu search with mathematical programming models. This method minimizes routing and inventory costs by efficiently coordinating operational decisions across a supply chain with multiple depots and flexible customer-hub assignments. The research includes computational experiments on 800 instances, achieving 99 optimal solutions for small instances and providing new best upper bounds for 159 cases. For larger instances, the algorithm delivers upper bounds within approximately 30 minutes, showcasing its effectiveness in both solution quality and computational time.
The second paper, “A Branch-and-Price Algorithm for the Two-Echelon Inventory-Routing Problem,” presents a route-based formulation and a branch-and-price algorithm to address the same problem. This approach aims to optimize inventory management and freight transportation coordination in a two-echelon supply network. The study involves a comprehensive numerical analysis of 400 newly generated instances, obtaining optimal solutions for 149 instances and providing upper bounds for 251 instances. The algorithm effectively minimizes transportation and inventory costs while meeting customer demands, with an average gap of 2.79% for some instances and 11.33% for others.
Both studies contribute valuable insights and methodologies for tackling the 2E-IRP, offering robust solutions that enhance supply chain efficiency.
Tom Van Woensel 