Supply Chain, Transportation And Inventory
According to the Logistics Bureau (2017) transportation may be defined as, “moving whatever comes out of one location to the next. That might mean transporting something from a manufacturer to a distributor, or from a distributor to a customer". Now where there is transportation taking place, there will most definitely be a need for an inventory system in order for the process of proper management of distribution to take place. “Inventory management is certainly a function of logistics but the influencers impacting inventory extend beyond the logistics network. Inventory requires a capital investment to build and stock finished goods. However, inventory is essential as the time a consumer is willing to wait for a product may be much less than the time it takes to manufacture the product and then ship the product to the customer need location. Inventory management considers a number of complex variables including; risk, lead time, cost, location, transport, and service levels”.
There are various types of inventory policy, such as the reorder point policy, the fixed-time period method, and the just-in-time strategy. These policies can be roughly divided into two basic types: the advance order policy (AOP) and the temporary order policy (TOP). The advance order policy states that in order to avoid being out of stock, items are stored in warehouses in advance, on the basis of materials consumption law. In contrast, under the temporary order policy, items are ordered when needed. For each inventory policy, we consider three major transportation modes: rail, truck, and air transport. It is generally known that the research on VRP (vehicle routing problem) and its various extensions has been extensive. However, other new domains on transportation can still be interesting topics. For example, the remarkable growth in intermodal transportation over the past decade has not been matched by a comparable level of academic activity, and, hence, the research on intermodal transportation appears to have a great potential.
Chang explores one of the intermodal operational issues: how to select best routes for shipments through the international intermodal network. The problem is formulated as a multiobjective multimodal multicommodity flow problem with time windows and concave costs, and an efficient heuristic is proposed. “Vermaa and Verter present a first attempt for the development of an analytical framework for planning rail-truck intermodal transportation of hazardous materials by developing a biobjective optimization model to plan and manage intermodal shipments to represent the current practice; the routing decisions in the model are driven by the delivery times specified by the customers. Bruns and Knust study the problem of load planning for trains in intermodal container terminals. The objective is to assign load units to wagons of a train such that the utilization of the train is maximized and setup and transportation costs in the terminal are minimized.
Bruns et al. further studied the problem of robust load planning for trains in intermodal container terminals. The goal of load planning is to choose wagon settings and assign load units to wagons of a train such that the utilization of the train is maximized and setup and transportation costs in the terminal are minimized. García et al. adopt a new hybrid approach by combining OR techniques with AI search methods in order to obtain good quality solutions for complex intermodal transport problems, by exploiting the benefits of both kinds of techniques. The solution has been applied to a real-world problem from one of the largest Spanish companies using intermodal transportation” – Xiang Li.
