The Inventory Routing Problem Sample Clauses

The Inventory Routing Problem. (IRP) Routing and inventory decisions are also required in the IRP, as well as in VRP. However, IRP is distinguished from VRP since there are no customer orders. Instead of customer orders, the delivery company decides which customers/terminals to visit and the size of the shipment per day/period. Another distinction is the planning horizon, IRP deals with a longer horizon than VRPs. The inventory levels need to be controlled by restrictions that impose the delivery company to operate in a way that their customers not are allowed to run out of products. [6] Xxxxxxxx et al. [6], indicates that IRP is considered as a long-term problem, however almost all proposed solution approaches simplifies the problem by solving only short term versions. Dror and Ball [17], were the first to develop an approach that concerned a 5-days perspective. A weekly schedule that applied node and arc exchanges to reduce costs in the planning period was proposed by Xxxx and Xxxx [18], and used as a basis for the rolling- horizon approach discussed in Xxxxxxx et al.[33] This approach contained a 2 weeks of scheduling, in which only the first week were implemented. Different studies of the inventory routing problem for a single product (s-IRP) can be found in Xxxxxxxxxxxx [7], Flatberg [24], and Fox and Xxxxxx [25], but in regard to our thesis, the inventory routing for multiple products is more interesting, a problem that is scarcely considered in the literature. However, a project between Møreforskning AS and the Norwegian company Omya Hustadmarmor led to a development of a decision-support system (DSS) for maritime inventory routing. The project led to an annual saving of 5 % of the company’s total cost, and increased the predictability and flexibility throughout the whole supply chain. [15] Oppen and Løkketangen [38], proposed a Xxxx Search based heuristic for Livestock Collection Problem (LCP). This problem deals with transportation of live animals to slaughterhouses and is based on the basic VRP, extended with production and inventory constraints. In contrast to the IRP, they considered the orders as data and therefore knew where to go and what to collect. A xxxxxxxxx plan is required to regulate the inventory level sufficiently, and is based on the inventory level of the previous day plus all animals received during the present day, and restricted by a minimum safety level and a lairage capacity. Xxxxxxxxxxxx [8], considered a multiple inventory routing problem where the focus...