Inventory routing problems for the management of returnable transportation items (RTI)

Abstract

This Master thesis proposes some modifications of the model developed by Iassinovskaia, Limbourg and Riane (2017) related to Pickup and Delivery Inventory Routing Problem with Time Windows (PDIRPTW) for the management of Returnable Transport Items (RTIs). The aim of these modifications is to better reflect the reality of the management of RTIs in organizations. The first improvement provided to the model refers to durability, resale and losses. The durability aspect relates to the fact that RTIs have a finite lifetime, which means that they can be used only a limited number of times. Then, the company has to dispose of these items and one interesting way to proceed is to resell them, hence the resale aspect which is strongly linked to the durability feature. Finally, the loss of RTIs is a frequent problem faced by companies. Both durability and losses generate the need to purchase more RTIs. The second and third modifications are about maximum ceiling constraints and minimum threshold constraints that are added to the initial model of Iassinovskaia et al. (2017). Some companies have to establish this kind of rules for some managerial or organizational reasons, although they result in some additional costs. These three main parts of the thesis are illustrated by some real-life situations drawn from the Master thesis of Martin (2016) and from the visits of different companies. Then, the models are developed and explained. After that, some analyses are performed and some conclusions are finally drawn.