Optimization Models in Logistics

In this thesis, we study three problems in logistics: Single Link Shipping, Vendor-Managed Inventory (VMI) and Scheduling. Firstly, we review the single link shipping problem in the case of multi-product and multi-modal shipping with given sets of frequencies and lead times. The contribution is on the single link case, that is due to the introduction of different sets of frequencies for each type of vehicles and to the introduction of lead times. Secondly, we introduce a two-echelon vendor-buyer supply chain model under VMI, which is more applicable to real-world inventory control systems. Then, considering that the objective function is very complex to solve exactly by using conventional techniques, some solution algorithms are used. Finally, we introduce the problem of scheduling on a single machine with focusing on Early/Tardy problem with distinct due dates. Then, an INLP model is formulated and an algorithm is developed in order to solve the single machine earliness and tardiness problem. For all the three problems, numerical results are discussed.