References of "Paquay, Célia"
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See detailL'art de charger le fret aérien
Paquay, Célia ULg

Article for general public (2017)

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See detailA best fit heuristic for the three-dimensional Bin Packing Problem with practical constraints from an air transportation application
Paquay, Célia ULg; Limbourg, Sabine ULg; Schyns, Michael ULg

in Proceedings of the BIVEC-GIBET Transport Research Days 2017 (2017)

This work 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 aim of ... [more ▼]

This work 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 aim of the present work is to find good initial solutions in short computational times. In this purpose, a fast best fit heuristic able to manage the different constraints to be met in transportation is developed. 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 rule. 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 parametrisation, computational experiments are performed on data sets specially designed for this application. The heuristic requires very short computational times to achieve promising results. [less ▲]

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See detailThe three-dimensional rectangular Multiple Bin Size Bin Packing Problem with transportation constraints: A case study in the eld of air transportation
Paquay, Célia ULg

Doctoral thesis (2017)

According to the International Air Transport Association and Air Transport Action Group, 51.3 million metric tons of goods were transported by airlines in 2014. To transport luggage, freight and mail ... [more ▼]

According to the International Air Transport Association and Air Transport Action Group, 51.3 million metric tons of goods were transported by airlines in 2014. To transport luggage, freight and mail, special containers, called Unit Load Devices (ULD), are used. The method of loading packages into ULDs represents a key element for cargo safety and aircraft weight and balance, as well as for the economy of airline companies. This thesis aims to solve the problem of packing a set of boxes into containers of various shapes without wasting loading space. The goal is to select the best set of ULDs to pack all the boxes achieving a minimum unused volume. As for all the packing problems, geometric constraints have to be satis ed: items cannot overlap and have to lie entirely within the bins. The richness of this application is to manage additional and common constraints: the bin weight limit, rotations, stability and fragility of the boxes, and weight distribution within a ULD. In practice, this problem is manually solved with no strict guarantee that the constraints are met. First, the problem is formulated as a mixed integer linear program. As this problem is NP-hard, it opens the way to heuristics. A second approach makes use of the formulation to apply three matheuristic methods, combining exact approaches and heuristics. Third, a tailored two-phase constructive heuristic is developed for this speci c problem; it aims to nd good initial solutions in short computational times. These approaches contain parameters that have been tuned using the irace parametrisation technique. For the experiments, several instances have been created on the basis of a box data set which stems from a real world case. [less ▲]

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See detailInstances for the 3D Multiple Bin Size Bin Packing Problem
Paquay, Célia ULg; Limbourg, Sabine ULg; Schyns, Michael ULg

Textual, factual or bibliographical database (2017)

The subject of this work is to solve the problem of packing a set of shipments (various cuboid boxes) into containers of various shapes without wasting loading space. All the boxes have to be loaded and ... [more ▼]

The subject of this work is to solve the problem of packing a set of shipments (various cuboid boxes) into containers of various shapes without wasting loading space. All the boxes have to be loaded and few are identical. As it is the case for all the packing problems, the packing has to satisfy geometry constraints: the items cannot overlap and have to lie entirely inside the bins. The richness of our application is to manage additional and common constraints: the bin weight capacity, the rotations of the boxes, the stability and the fragility of the boxes and the uniformity of the weight distribution inside the ULDs. The last constraint is crucial in air transportation: when ULDs are packed inside the airplane, the centre of gravity is computed assuming each ULD has a centre of gravity close to the geometrical centre of its basis. This type of constraints can be adapted to road transportation for the axle weight limits, which plays a key role since the weigh-in-motion systems become more common. [less ▲]

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See detailA tailored two-phase constructive heuristic for the three-dimensional Multiple Bin Size Bin Packing Problem with transportation constraints
Paquay, Célia ULg; Limbourg, Sabine ULg; Schyns, Michael ULg

E-print/Working paper (2017)

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 with minimising unused space. The problem ... [more ▼]

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 with minimising unused space. The problem is extended to air cargo where bins are Unit Load Devices, especially designed for fitting in aircraft. We developed a fast constructive heuristic able to manage the different constraints 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. During this phase, the fragility, stability and orientations of the boxes are taken into account as well as the special shape of the bins and their weight capacity. The second phase takes into account the multiple types of available bins. If necessary, the best found loading pattern is finally enhanced with respect to weight distribution in a post processing. After parametrisation, computational experiments have been performed on data sets especially designed for this application. The heuristic requires really short computational times to achieve promising results. [less ▲]

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See detailOptimal returnable transport items management
Limbourg, Sabine ULg; Martin, Adeline; Paquay, Célia ULg

Conference (2016, July 11)

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their returnable transport items (RTIs) among the different partners of a ... [more ▼]

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their returnable transport items (RTIs) among the different partners of a closed-loop supply chain. Face-to-face interviews with senior executives from seven companies involved in RTIs were conducted to gain a thorough understanding of how they manage the flow of RTIs as well as how they determine the number of RTIs needed in a fleet. Results indicate that RTIs managements are quite diverse, that some common beliefs about RTIs do not apply to all RTI types, and that research efforts are needed in the areas of RTI acquisition; warehouse layout, inventory routing problem; production planning and control; tracking and scheduling. [less ▲]

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See detailA Mixed Integer Programming formulation for the three dimensional bin packing problem deriving from an air cargo application
Paquay, Célia ULg; Schyns, Michael ULg; Limbourg, Sabine ULg

in International Transactions in Operational Research (2016), 23(1-2), 187-213

The present paper looks into the problem of optimising the loading of boxes into containers. The goal is to minimise the unused volume. This type of problem belongs to the family of Multiple Bin Size Bin ... [more ▼]

The present paper looks into the problem of optimising the loading of boxes into containers. The goal is to minimise the unused volume. This type of problem belongs to the family of Multiple Bin Size Bin Packing Problems. 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. [less ▲]

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See detailLogistics hub: the case of Liège
Limbourg, Sabine ULg; Mostert, Martine ULg; Paquay, Célia ULg

Conference (2014, April 24)

A logistics hub can be defined as a specific area where all the activities relating to transport, logistics and goods distribution are carried out. With its central location in Europe, highly developed ... [more ▼]

A logistics hub can be defined as a specific area where all the activities relating to transport, logistics and goods distribution are carried out. With its central location in Europe, highly developed infrastructures, airport and inland terminals, the region of Liège claims to be a logistics hub. This paper applies a strategic decision model based on seven relevant criteria (infrastructure, proximity to market, land availability, government and industry support, labour supply, origin/destination distances and congestion) to assess the efficiency of the logistics hub of the region of Liège. Two SWOT analyses are performed in parallel to evaluate the positions of Liège Airport and of the inland freight hub, Trilogiport, in relation to their own performances and the competition. The two main development factors of inland freight hubs are considered: the possibility of modal shift from road transport to more environmentally friendly transportation modes and the avoidance of the congestion of the two seaport areas of Antwerp and Rotterdam. This article concludes by highlighting that the bid of the region of Liège and its characteristics should contribute to a more efficient intermodal transport in Europe, helping to boost the distribution of products, and at the same time, encourage the reduction of greenhouse gas emissions. However, the development of Liège as an inland freight hub depends on its ability to generate a critical mass, notably thanks to the local businesses, in order to realise economies of scale. [less ▲]

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See detailA constructive heuristic for the three dimensional Bin Packing Problem with transportation constraints
Paquay, Célia ULg; Schyns, Michael ULg; Limbourg, Sabine ULg

Conference (2014)

The aim of this work is to propose a Relax-And-Fix heuristic to build a good initial solution to the 3D BPP. First, a mathematical formulation has been developed taking into account several types of ... [more ▼]

The aim of this work is to propose a Relax-And-Fix heuristic to build a good initial solution to the 3D BPP. First, a mathematical formulation has been developed taking into account several types of constraints such as the stability and fragility of the boxes to pack, their possibility to rotate, the weight distribution inside the bins and their special shapes. Since this model contains a lot of integer variables, we have decided to apply the Relax-and-Fix method. We have selected several sets of variables to be the branching variables and carried out some tests. [less ▲]

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See detailThree dimensional Bin Packing Problem applied to air cargo
Paquay, Célia ULg; Schyns, Michael ULg; Limbourg, Sabine ULg

in ILS 2012 Proceedings (2012, August 26)

Deciding whether a set of three dimensional boxes can be packed into a container is a NP-hard problem. Mathematical models have been developed, however, only few studies take into account constraints ... [more ▼]

Deciding whether a set of three dimensional boxes can be packed into a container is a NP-hard problem. Mathematical models have been developed, however, only few studies take into account constraints encountered in real-world applications such as the stability or the fragility of the cargo. Moreover, despite the importance of this issue in air transport, the literature is almost silent on constraints related to the distribution of the weight inside a container. This paper is concerned with the formulation of the three dimensional palletization which includes the main constraints met in the air cargo industry. [less ▲]

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See detailOptimisation 3D du chargement de conteneurs pour le transport aérien
Paquay, Célia ULg; Limbourg, Sabine ULg; Schyns, Michael ULg

in LigéRO (Ed.) Proceedings ROADEF 2013 (2012, April 11)

De nos jours, décider comment remplir des conteneurs avec des colis est une activité courante aussi bien dans le domaine du transport routier qu’aérien. Ce type de question est apparentée aux problèmes de ... [more ▼]

De nos jours, décider comment remplir des conteneurs avec des colis est une activité courante aussi bien dans le domaine du transport routier qu’aérien. Ce type de question est apparentée aux problèmes de Bin-Packing(BPP) en recherche opérationnelle. En termes économiques, ces opérations doivent mener à une solution qui satisfait de nombreuses contraintes physiques, être réalisées rapidement et de sorte à maximiser certains critères. Typiquement, on tentera de charger un maximum de colis dans un minimum de conteneurs pour réduire les coûts. [less ▲]

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See detailThree dimensional Bin Packing Problem applied to air transport
Paquay, Célia ULg; Schyns, Michael ULg; Limbourg, Sabine ULg

Conference (2012, February 02)

Packing boxes into containers is a daily process in many di erent elds and especially in transport. However, the particular case of air transport brings some new constraints such as the stability or the ... [more ▼]

Packing boxes into containers is a daily process in many di erent elds and especially in transport. However, the particular case of air transport brings some new constraints such as the stability or the fragility of the cargo. The distribution of the weight has also to be considered. Moreover, this special case also brings some data such as the dimensions of the possible containers, called Unit Load Devices. This paper is concerned with the formulation of the three dimensional palletization which includes the main constraints met in the air cargo industry. It proposes a integer linear program for this combinatorial optimization problem. [less ▲]

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See detailThree Dimensional Bin Packing Problem applied to air cargo
Paquay, Célia ULg; Schyns, Michael ULg; Limbourg, Sabine ULg

Scientific conference (2011, December 15)

Deciding whether a set of three dimensional boxes can be packed into a container is a NP-hard problem. Mathematical models have been developed, however, only few studies take into account constraints ... [more ▼]

Deciding whether a set of three dimensional boxes can be packed into a container is a NP-hard problem. Mathematical models have been developed, however, only few studies take into account constraints encountered in real-world applications such as the stability or the fragility of the cargo. Moreover, despite the importance of this issue in air transport, the literature is almost silent on constraints related to the distribution of the weight inside a container. This paper is concerned with the formulation of the three dimensional palletization which includes the main constraints met in the air cargo industry. [less ▲]

Detailed reference viewed: 184 (14 ULg)