Container Repositioning Research Articles

A multi-scenario model for empty container repositioning with uncertain demand

This paper investigates the maritime repositioning of empty containers when their demand is uncertain. It involves moving empty containers from import-dominant ports to export-dominant ports in anticipation of future demands. In order to consider demand uncertainty, the problem is addressed by a stochastic programming approach, in which different scenarios are included in a multi-scenario optimisation model and explicitly linked by non-anticipativity conditions. Numerical experiments are carried out to show which benefits are obtained by multi-scenario solutions with respect to their deterministic counterparts, which consider only one point forecast for each uncertain parameter.

Maritime Empty Container Repositioning

Maritime shipping containers are important to a number of different industries as they facilitate the reduction of transportation costs. To address the needs of shippers, empty containers need to be repositioned globally between seaports. Since the cost of empty container repositioning (ECR) constitutes a significant element of the total cost of running a global container fleet operation, the problem has been receiving increasing attention from scholars. The diversity of this literature necessitates the development an appropriate classification scheme to identify trends, gaps, and directions for future research. This paper reviews publications on maritime ECR over the last two decades and examines such trends and potential research directions.

Long-haul liner service route design with ship deployment and empty container repositioning

This paper proposes a single liner long-haul service route design problem including route structure design, ship deployment and empty container repositioning. The objective of this problem is to minimise the total cost incurred from a liner long-haul service route, including ship related costs, fuel consumption costs, port related costs, laden containers and empty container inventory-in-transition costs. We propose a three-stage optimisation method to tackle the problem. We introduce the notions of topological structure and ship load factors, which lead to a classification of shipping route structures and the relationships between the container flow pattern and the route structure. This greatly simplifies the route structure design decisions at the first stage and enables us to develop an efficient heuristic algorithm to reposition empty containers at the second stage. The ship deployment problem concerning the number of ships and their capacity and sailing speeds is considered at the third stage. The model takes advantage of the characteristics of the existing route structures and can solve the service route design problems effectively from the practical perspective. In addition, the established relationships between the load factors and the route structure provide useful insights into ship utilisation and route structure choice. Case studies are presented to show efficiency and applicability of the proposed research methodology.

Reducing hinterland transportation costs through container sharing

Based on two scenarios which describe the movement of full and empty containers within seaport hinterland transportation, this contribution determines possible benefits of exchanging empty containers between cooperating trucking companies. In the first scenario, trucking companies only have access to their own containers. In the second scenario, empty containers are permitted to be interchanged among several owners. Descriptions of both scenarios are given by comprehensive mathematical formulations considering vehicle routing, simultaneously with empty container repositioning. Realistic-sized instances are solved by applying an efficient tabu search heuristic. The results show that container sharing between trucking companies leads to remarkable cost savings.

The sample average approximation method for empty container repositioning with uncertainties

One of the challenges faced by liner operators today is to effectively operate empty containers in order to meet demand and to reduce inefficiency in an uncertain environment. To incorporate uncertainties in the operations model, we formulate a two-stage stochastic programming model with random demand, supply, ship weight capacity, and ship space capacity. The objective of this model is to minimize the expected operational cost for Empty Container Repositioning (ECR). To solve the stochastic programs with a prohibitively large number of scenarios, the Sample Average Approximation (SAA) method is applied to approximate the expected cost function. To solve the SAA problem, we consider applying the scenario aggregation by combining the approximate solution of the individual scenario problem. Two heuristic algorithms based on the progressive hedging strategy are applied to solve the SAA problem. Numerical experiments are provided to show the good performance of the scenario-based method for the ECR problem with uncertainties.

Stochastic Optimization of Empty Container Repositioning of Sea Carriage

To improve the efficiency of empty container repositioning for a shipping company, a stochastic optimization model of empty container repositioning of sea carriage was established by chance-constrained programming. The objective function was to minimize the cost of empty container repositioning including shipping, rening and shortage cost. In the model, shipping cost was decided by the number of ship used for empty container repositioning. The constraints of the model included meeting the need of empty containers, limit to the number of empty containers provided and the capacity of shipping. The numbers of empty containers required are stochastic. The stochastis model was transferred to an integer programming one. Lingo9.0 was used to solve the model and simulation was done under varied parameters to get a good shipping strategy. The results show that the model can provide an effective program of empty container repositioning for a shipping company and it is a good way to raise shipping efficiency.

Liner Shipping Cargo Allocation with Repositioning of Empty Containers

This paper is concerned with the cargo allocation problem considering empty repositioning of containers for a liner shipping company. The aim is to maximize the profit of transported cargo in a network, subject to the cost and availability of empty containers. The formulation is a multi-commodity flow problem with additional inter-balancing constraints to control repositioning of empty containers. In a study of the cost efficiency of the global container-shipping network, Song et al. (2005) estimate that empty repositioning cost constitutes 27% of the total world fleet running cost. An arc-flow formulation is decomposed using the Dantzig-Wolfe principle to a path-flow formulation. A linear relaxation is solved with a delayed column generation algorithm. A feasible integer solution is found by rounding the fractional solution and adjusting flow balance constraints with leased containers. Computational results are reported for seven instances based on real-life shipping networks. Solving the relaxed linear path-flow model with a column generation algorithm outperforms solving the relaxed linear arc-flow model with the CPLEX barrier solver even for very small instances. The proposed algorithm is able to solve instances with 234 ports, 16,278 demands over 9 time periods in 34 min. The integer solutions found by rounding down are computed in less than 5 s and the gap is within 0.01% from the upper bound of the linear relaxation. The solved instances are quite large compared to those tested in the reviewed literature.

Liner shipping service network design with empty container repositioning

This paper proposes a liner shipping service network design problem with combined hub-and-spoke and multi-port-calling operations and empty container repositioning. It first introduces a novel concept – segment – defined as a pair of ordered ports served by one shipping line and subsequently develops a mixed-integer linear programming model for the proposed problem. Extensive numerical experiments based on realistic Asia–Europe–Oceania shipping operations show that the proposed model can be efficiently solved by CPLEX for real-case problems. They also demonstrate the potential for large cost-savings over pure hub-and-spoke or pure multi-port-calling network, or network without considering empty container repositioning.

A Fluid Flow Model for Empty Container Repositioning Policy with a Single Port and Stochastic Demand

This paper is concerned with an optimal policy for empty container repositions. A single port is considered. The demand is modeled as a two-state Markov chain. The objective is to transport in and out containers so as to minimize the discounted holding, leasing, and repositioning costs. In this paper, the flow of containers is treated as though it is a continuous fluid. Dynamic programming is used to solve the optimal control problem. The associated HJB equations are used to characterize the value functions. The optimal policies are given in terms of threshold levels. Closed-form solutions of these threshold levels are obtained. Sufficient conditions are given in the form of a verification theorem. Numerical examples are reported to demonstrate the results.

Optimal slot allocation with empty container reposition problem for Asia ocean carriers

This paper utilises revenue management modelling to make an optimal slot allocation serving a specific shipping service route for ocean carriers. The model, incorporating the expected cost of empty container reposition, is formulated through mathematical programming to maximise operational profit of ocean carriers, subject to some constraints of vessel capacity, container demand and empty container supply. Computational results not only present port-to-port slot allocation to be a guideline to implement space control but also provide a criterion to review the status of strategic alliance among ocean carriers.

Optimal container dispatching policy and its structure in a shuttle service with finite capacity and random demands

This paper considers the container-dispatching problem including laden container distributing and empty container repositioning in a two-terminal shuttle service with finite shipping capacity and random customer demands. Unmet demands within one period due to unavailable shipping capacity or insufficient empty containers will be lost based on the assumption that customers have limited patience and the fact that container shipping is a highly competitive sector. The objective is to seek effective container dispatching policies by minimising the total costs incurred by container inventory, container repositioning and lost sales. The optimal dispatching policy is derived by applying the Markov decision process theory. The structural characteristics of the optimal policy are investigated through numerical examples. Based on these structural properties, a four-parameter threshold policy is constructed. A range of numerical examples demonstrates that the proposed threshold policy performs extremely close to or indeed the same as the optimal policy. More importantly, the proposed policy has an explicit form, which is easy-to-understand and easy-to-operate from the managerial and operational perspectives.

Multi-port vs. Hub-and-Spoke port calls by containerships

This paper addresses the design of container liner shipping networks taking into consideration container management issues including empty container repositioning. We examine two typical service networks with different ship sizes: multi-port calling by conventional ship size and hub-and-spoke by mega-ship. The entire solution process is performed in two phases: the service network design and container distribution. A wide variety of numerical experiments are conducted for the Asia–Europe and Asia–North America trade lanes. In most scenarios the multi-port calling is superior in terms of total cost, while the hub-and-spoke is more advantageous in the European trade for a costly shipping company.

Immunity-based hybrid evolutionary algorithm for multi-objective optimization in global container repositioning

The development of evolutionary algorithms for optimization has always been a stimulating and growing research area with an increasing demand in using them to solve complex industrial optimization problems. A novel immunity-based hybrid evolutionary algorithm known as Hybrid Artificial Immune Systems (HAIS) for solving both unconstrained and constrained multi-objective optimization problems is developed in this research. The algorithm adopts the clonal selection and immune suppression theories, with a sorting scheme featuring uniform crossover, multi-point mutation, non-dominance and crowding distance sorting to attain the Pareto optimal front in an efficient manner. The proposed algorithm was verified with nine benchmarking functions on its global optimal search ability as well as compared with four optimization algorithms to assess its diversity and spread. Sensitivity analysis was also carried out to investigate the selection of key parameters of the algorithm. It is found that the developed immunity-based hybrid evolutionary algorithm provides a useful means for solving optimization problems and has successfully applied to the problem of global repositioning of containers, which is one of a constrained multi-objective optimization problem. The developed HAIS will assist shipping liners on timely decision making and planning of container repositioning operations in global container transportation business in an optimized and cost effective manner.

Empty container reposition planning for intra-Asia liner shipping

This paper addresses empty container reposition planning by plainly considering safety stock management and geographical regions. This plan could avoid drawback in practice which collects mass empty containers at a port then repositions most empty containers at a time. Empty containers occupy slots on vessel and the liner shipping company loses chance to yield freight revenue. The problem is drawn up as a two-stage problem. The upper problem is identified to estimate the empty container stock at each port and the lower problem models the empty container reposition planning with shipping service network as the Transportation Problem by Liner Problem. We looked at case studies of the Taiwan Liner Shipping Company to show the application of the proposed model. The results show the model provides optimization techniques to minimize cost of empty container reposition and to provide an evidence to adjust strategy of restructuring the shipping service network.

Decision Support for Optimal Repositioning of Containers in a Feeder System

The transport of empty containers represents a seriousproblem in the fast growing sphere of maritime container transport.The most widespread type of container transport organizationin maritime transport is the hub and spoke mode, whichenables the transport of a great number of containers via largevessels between hub ports, from where feeder ships transport tosmaller ports that thus gravitate to the central hub port. The articlecontains a detailed analysis of the northern Adriatic portsand the feeder connections with the hub ports of the Mediterranean.A two-level VRPPD (Vehicle Routing Problem withPickup and Delivery) problem is modelled on a graph, wherethe transport of full containers is privileged over the transport ofempty containers. This enables the simulation of the feeder systemin the n01them Adriatic, meaning that it shows the ship'soperator the movement programme with minimal transportcosts for the superfluous empty containers in the complex of theregular transports of full containers in the feeder system.

Research on the Optimization of Intermodal Empty Container Reposition of Land-carriage

This paper uses integer programming to investigate reposition of intermodal empty containers of land-carriage. In the model, the objective is to minimize the cost of distributing empty containers from port to port—from supplier to port, from port to demander. It takes into consideration the following factors. First, the requirement of empty containers from the demanders and the ability of the suppliers to supple empty containers are satisfied. Second, the ability to store empty containers in the ports and load limit to empty containers by varied transport methods is satisfied. Lingo 8.0 is adopted to solve the model. Results obtained from the computation show that the model can reduce the reposition cost effectively under the condition that it satisfies the requirement from the demanders, the ability of suppliers to supply and storage ability in the port, etc. The model has raised the efficiency of repositioning of intermodal empty containers of land-carriage by a shipping company.

Characterizing optimal empty container reposition policy in periodic-review shuttle service systems

This paper considers a periodic-review shuttle service system with random customer demands and finite reposition capacity. The objective is to find the optimal stationary policy of empty container reposition by minimizing the sum of container leasing cost, inventory cost and reposition cost. Using Markov decision process approach, the structures of the optimal stationary policies for both expected discounted cost and long-run average cost are completely characterized. Monotonic and asymptotic behaviours of the optimal policy are established. By taking advantage of special structure of the optimal policy, the stationary distribution of the system states is obtained, which is then used to compute interesting steady-state performance measures and implement the optimal policy. Numerical examples are given to demonstrate the results.

Foldable Containers to Reduce the Costs of Empty Transport? A Cost–Benefit Analysis from a Chain and Multi-Actor Perspective

Transport of empty containers, which arises from the need to reposition containers, is an expensive business. This holds in particular for shipping lines, which are usually responsible for container repositioning and have to bear these container management costs. Shipping lines are known to follow various strategies to reduce the costs of empty transport. A rather unfamiliar, but interesting option to save costs is the possibility to fold empty containers. This could save transport costs, but also transhipment and storage costs. In this paper, we analyse the opportunities for commercial application of foldable containers. For this purpose a cost–benefit analysis is adopted in which four logistic concepts to use foldable containers are presented as a framework for analysis. The costs and benefits of using foldable containers in these logistic concepts are calculated and compared with the situation in which standard containers are used. It is shown that the use of foldable containers can lead to substantial net benefits in the total chain of container transport. However, much depends on the additional costs that foldable containers cause, that is, the cost of folding and unfolding, additional exploitation costs and any additional transport to places where folding and unfolding can take place. The logistic concept plays a part in it, but it should be a great challenge for designers and container producers to develop a foldable container that generates limited additional costs.

The container shipping network design problem with empty container repositioning

This paper addresses the design of container liner shipping service networks by explicitly taking into account empty container repositioning. Two key and interrelated issues, those of deploying ships and containers are usually treated separately by most existing studies on shipping network design. In this paper, both issues are considered simultaneously. The problem is formulated as a two-stage problem. A genetic algorithm-based heuristic is developed for the problem. Through a number of numerical experiments that were conducted it was shown that the problem with the consideration of empty container repositioning provides a more insightful solution than the one without.

A GENETIC ALGORITHM BASED APPROACH TO CONSTRUCTING CONTAINER SHIPPING NETWORKS WITH EMPTY CONTAINER REPOSITIONING AMONG CALLING PORTS

This paper addresses the design of container liner shipping service networks by explicitly taking into account empty container repositioning and container fleet size. Two key and interrelated issues of deployments of ships and containers are usually treated separately by most existing studies on shipping network design. In this paper, both issues are considered simultaneously. The problem is formulated as a two-stage problem: the upper-problem being formulated as a Knapsack problem and the lower-problem as a Flow problem. A genetic algorithm based heuristic is developed for the problem. Through a number of numerical experiments that were conducted it was shown that the problem considering empty container repositioning provides a more insightful solution than the one without.