Sabine Limbourg

Automatic Aircraft Cargo Load Planning

The goal of this paper is the development of a new mixed integer linear program designed for optimally loading a set of containers and pallets into a compartmentalised cargo aircraft. It is based on real-world problems submitted by a professional partner. This model takes into account strict technical and safety constraints. In addition to the standard goal of optimally positioning the centre of gravity, we also propose a new approach based on the moment of inertia. This double goal implies an increase in aircraft efficiency and a decrease in fuel consumption. Cargo loading generally remains a manual, or at best a computer-assisted, and time-consuming task. A fully automatic software was developed to quickly compute optimal solutions. Experimental results show that our approach achieves better solutions than manual planning, within only a few seconds.

A mixed integer programming formulation for the three‐dimensional bin packing problem deriving from an air cargo application

The present paper discusses the problem of optimizing the loading of boxes into containers. The goal is to minimize the unused volume. This type of problem belongs to the family of multiple bin size bin packing problems (MBSBPP). The approach includes an extensive set of constraints encountered in real-world applications in the three-dimensional case: the stability, the fragility of the items, the weight distribution, and the possibility to rotate the boxes. It also includes the specific situation in which containers are truncated parallelepipeds. This is typical in the field of air transportation. While most papers on cutting and packing problems describe ad hoc procedures, this paper proposes a mixed integer linear program. The validity of this model is tested on small instances.

Capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints

In this paper, we introduce and study the capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints. To the best of our knowledge, it is the first time that axle weight restrictions are incorporated in a vehicle routing model. The aim of this paper is to demonstrate that incorporating axle weight restrictions in a vehicle routing model is possible and necessary for a feasible route planning. Axle weight limits impose a great challenge for transportation companies. Trucks with overloaded axles represent a significant threat for traffic safety and may cause serious damage to the road surface. Transporters face high fines when violating these limits. A mixed integer linear programming formulation for the capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints is provided. Results of the model are compared to the results of the model without axle weight restrictions. Computational experiments demonstrate that the model performs adequately and that the integration of axle weight constraints in vehicle routing models is required for a feasible route planning.

MIP-based constructive heuristics for the three-dimensional Bin Packing Problem with transportation constraints

Abstract This article is about seeking a good feasible solution in a reasonable amount of computation time to the three-dimensional Multiple Bin Size Bin Packing Problem (MBSBPP). The MBSBPP studied considers additional constraints encountered in real world air transportation situations, such as cargo stability and the particular shape of containers. This MBSBPP has already been formulated as a Mixed Integer linear Programming problem, but as yet only poor results have been achieved for even fairly small problem sizes. The goal of the work this paper describes is to develop heuristics that are able to quickly provide good initial feasible solutions for the MBSBPP. Three methodologies are considered, which are based on the decomposition of the original problem into easier subproblems: the matheuristics Relax-and-Fix, Insert-and-Fix and Fractional Relax-and-Fix. They have been parametrised on real data sets and then compared to each other. In particular, two of these techniques show promising results in reasonable computational times.

Iterated local search for the capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints

In this article an Iterated Local Search algorithm for the capacitated vehicle routing problem with sequence-based pallet loading and axle weight constraints is presented. Axle weight limits impose a great challenge for transportation companies. Yet, the literature on the incorporation of axle weight constraints in vehicle routing models is very scarce. The effect of introducing axle weight constraints in a CVRP on total routing cost is analyzed. Results show that integrating axle weight constraints does not lead to a large cost increase. However, not including axle weight constraints in the planning process may induce major axle weight violations.

A tailored two-phase constructive heuristic for the three-dimensional Multiple Bin Size Bin Packing Problem with transportation constraints

This paper considers the three-dimensional Multiple Bin Size Bin Packing Problem which consists in packing a set of cuboid boxes into containers of various shapes, while minimising unused space. The problem is extended to air cargo where the bins are Unit Load Devices, specially designed for fitting in aircraft. We developed a fast constructive heuristic able to manage the constraints to be met in transportation. The heuristic is split into two distinct phases. The first phase deals with the packing of boxes into identical bins using an extension of the Extreme Points which describe the possible interesting positions to accommodate boxes. During this phase, the fragility, stability and orientation of the boxes are taken into account as well as the special shape of the bins and their weight capacity. The second phase considers the multiple types of available bins. If necessary, the best loading pattern identified is enhanced with respect to weight distribution in post processing. After the description of the parametrisation, computational experiments are performed on data sets specially designed for this application. The heuristic requires only few seconds to achieve promising results in terms of filling rate.

A road map for explorative scenario creation on Belgian rail freight transport development

The starting point of this article is the weak usage of rail freight in Belgium and Europe, both as a sustainable mode of land transportation in itself as well as a part of the intermodal chain. The results are obtained by transversal research on rail freight transport in Belgium, taking into account the European context. This interdisciplinary research develops a road map for the creation of three integrated scenarios: a best case, medium case and worst case scenario for rail freight development, based on a detailed SWOT (strength, weakness, opportunities, threats) analysis. It includes the most probable future developments for rail freight transport and hinterland connections. These developments are obtained from literature review and discussions with a heterogeneous panel of experts in the fields of (i) optimal corridor and hub development, (ii) macroeconomic impact, (iii) sustainability, (iv) effective market regulation and (v) governance and organization for a well-functioning intermodality. The Delphi approach is used in combination with a survey analysis. Frequency tables and the H-index allow defining a ranking and selection of SWOT elements. The obtained scenarios allow future research to quantify and measure the impact of future developments and decisions towards the Belgian rail freight market.