Dynamic shipments of inventories in shared warehouse and transportation networks

In shared warehouse and transportation networks, dynamic shipments of inventories are carried out based on up-to-date inventory information. This paper studies the effect of network structures on optimal decision-making. We propose a discrete time modeling framework with stochastic demand, capturing a wide variety of network structures. Using Markov decision processes, we obtain optimal order and dynamic shipment decisions for small networks. We compare optimal solutions of different four-node network structures. Results indicate product characteristics significantly influence the effectiveness of network structures. Surprisingly, two-echelon networks are occasionally costlier than any other network. Moreover, dynamic shipments yield considerable gains over static shipments

Gamification of warehousing: exploring perspectives of warehouse managers in the UK

Contemporary warehouses are key links in the supply chains in competitive global business environments and with rapidly evolving trends in technology they need to adapt to the evolving needs of customers. Gamification recently emerged as a potential means of improving employee engagement leading to increased operational efficiency. This article therefore explores the perspectives of warehouse managers in the UK on gamification of warehousing activities. The findings suggest that gamification is applicable in the warehousing context with potential benefits such as improved worker engagement, increased morale and productivity, enforced competition, increased accuracy, and skills development. However, there are also significant barriers to effective implementation – these include resource constraints, gamification efficacy over time, ethical considerations, and ensuring fairness for all players. The findings from this study provide some valuable insights, thereby providing a rational basis for potentially fruitful future research in this area of growing interest

2009. Scheduling of container storage and retrieval

Abstract We consider the problem of scheduling the storage and retrieval of containers in the storage area of a container terminal. Some arcs in the underlying directed network must be visited; other arcs may -but need not be -visited. We can, therefore, consider this problem to be a special case of the directed Rural Postman Problem. We show that this problem can be reformulated as an asymmetric Steiner Traveling Salesman Problem. This reformulation can be efficiently solved to optimality by a combination of optimal assignments in bipartite networks for parts of the problem and dynamic programming for the connections between those parts

Transshipment and rebalancing policies for library books

Library customers can soon order books online and specify a location to collect them from. Libraries exchange books between locations to meet these requests. Two types of exchanges take place: transshipments from library to library to fulfill the requests and rebalancing to redistribute books between libraries. This research determines optimal decisions for transshipments and rebalancing, so that logistic costs in the library system are minimized. In current practice, libraries typically send the book back to the original library after return. We consider a more general policy, in which we rebalance books in anticipation of demand. Moreover, we determine the optimal location from which to transship a book when it is unavailable at the location of demand. By means of stochastic dynamic programming, we derive the optimal policy for small instances. For larger instances we present two heuristics: the cluster and the expected shortage reduction (ESR) heuristic. The ESR heuristic proves to be near-optimal and significantly outperforms current practice. (C) 2013 Elsevier B.V. All rights reserved

Determination of the number of automated guided vehicles required at a semi-automated container terminal

This paper describes the development of a minimum flow algorithm to determine the number of automated guided vehicles (AGVs) required at a semi-automated container terminal. At such a terminal the containers are transported by AGVs from the quay cranes to the automated stacking cranes and vice versa. A model and a strongly polynomial time algorithm are developed to solve the case in which containers are available for transport at known time instants