The economic and environmental feasibility of biogas buses in Liege

in 2013 BIVEC-GIBET Transport Research Days - Proceedings (2013, May 30)

Everyday, many students at the University of Liège have to drive to the Sart-Tilman village to attend their courses. These journeys are responsible for the emission of harmful particles which have ... [more ▼]

Everyday, many students at the University of Liège have to drive to the Sart-Tilman village to attend their courses. These journeys are responsible for the emission of harmful particles which have negative impacts on climate and human health. This paper analyzes the economic and environmental feasibility of using biogas buses for public transport in Liège. The idea of implementing biogas buses is based on the proposed recycling of organic waste by the company INTRADEL, which manages and treats waste in the region. The economic and environmental advantages and drawbacks of biogas buses are developed and compared with those of the current diesel bus fleet. The main conclusion of this study is that, while internalizing external costs due to pollution, the use of biogas buses becomes an attractive option compared with classical diesel buses. Nevertheless, it requires investment and might lead to resistance to change. However, it remains a good solution for the reduction of CO2 emissions. [less ▲]

Optimization model for empty container repositioning

Scientific conference (2013, February 07)

Empty container management is a transportation issue relating to the imbalance of container demand and supply. This project aims at minimizing the overall cost of empty container management. It takes ... [more ▼]

Empty container management is a transportation issue relating to the imbalance of container demand and supply. This project aims at minimizing the overall cost of empty container management. It takes account of transit time, shipping cost, the carrying capacity of the various modes of transport, the stochastic demand and supply of each terminal and port as well as other parameters such as substitution or holding costs, plus the intermodality with road transportation. [less ▲]

The sensitivity of optimal rail‐road terminal locations to intermodal freight costs variations

Conference (2012, September 05)

In the last decades, the market of goods became globalized, increasing international trade relations and the demand for long distance transportation. As a consequence of the larger distances traveled and ... [more ▼]

In the last decades, the market of goods became globalized, increasing international trade relations and the demand for long distance transportation. As a consequence of the larger distances traveled and of the containerization of goods, maritime transportation became more efficient and reliable. In the hinterland, intermodal (rail-road) freight transportation emerged as a competitive alternative to truck-only transportation. In one of its possible meanings, intermodal freight transportation is the multimodal chain of container-transportation services [1] that, e.g., brings containers from (or to) the seaport by barge or rail to (or from) an intermodal terminal in the hinterland from where they are shipped by truck to their final destination (or origin). This study focus on inland intermodal freight transport, in particular, on the rail–truck transport of cargo containers in Belgium. This European country has a long rail system and in the last years has readapted this system in order to handle with containerized cargo. Since 2004, some rail-road terminals have been built and new intermodal services between the seaports of Belgium have been established. In addition, with the aim of promoting the modal share of intermodal rail-road transport, the federal government of Belgium started subsidizing part of the rail transport cost and of the transshipments costs at the rail-road terminals. With these investments the intermodal freight flows in Belgium have increased. [less ▲]

Network design model for intermodal transport: the case of the hinterland of the Port of Cotonou

in ILS 2012 Proceeding (2012, August 27)

Since 2006, the Millennium Challenge Account program subsidizes a project to improve the performance of the Port of Cotonou, through modernization of infrastructure and management systems, and ... [more ▼]

Since 2006, the Millennium Challenge Account program subsidizes a project to improve the performance of the Port of Cotonou, through modernization of infrastructure and management systems, and strengthening institutional reforms. But the project mainly concerns the port, not the development of its hinterland. However, no port can develop without its links with its hinterland. That’s why we analyse the issues relating to the hinterland transport network. Both rail and road transportation networks will be examined. We also investigate inland terminals in order to build up intermodal transportation which is almost non-operational. Thus, the objective of this paper is to determine the optimal number and locations of the terminals so that the total costs of the distribution network are minimized. [less ▲]

Intermodal transportation network design under uncertainty: case of the hinterland of the Port of Cotonou

Scientific conference (2012, May 21)

Since 2006, the Millennium Challenge Account program subsidizes a project to improve the performance of the Port of Cotonou, through modernization of infrastructure and management systems, and ... [more ▼]

Since 2006, the Millennium Challenge Account program subsidizes a project to improve the performance of the Port of Cotonou, through modernization of infrastructure and management systems, and strengthening institutional reforms. But the project mainly concerns the port, not the development of its hinterland. However, no port can develop without its links with its hinterland. That’s why we analyse the issues relating to the hinterland transport network. Thus, rail and road transportation networks will be examined. Also, we will investigate inland terminals in order to build up intermodal transportation which is almost non-operational. But in the case of freight transportation from and to the hinterland of the port of Cotonou, two uncertainties occurred. So, we have to deal with the variability of the traffic and the road capacity. Indeed, the road capacity is restricted by the level of the torrential rains in worst period, as some arcs of the road are damaged. As a first step, the objective of this paper is to determine the optimal number and locations of the terminals so that the total costs of the distribution network are minimized. [less ▲]

Chargement de marchandises dans un avion cargo: le cas des marchandises nécessitant des précautions particulières

Conference (2012, April)

D'une part, les entreprises de transport aérien ont acheminé en 2010 plus d’un tiers de la valeur des exportations mondiales. D'autre part, le chargement des avions est une opération complexe soumise à de ... [more ▼]

D'une part, les entreprises de transport aérien ont acheminé en 2010 plus d’un tiers de la valeur des exportations mondiales. D'autre part, le chargement des avions est une opération complexe soumise à de nombreuses contraintes et peu d'outils sont disponibles pour aider les loadmasters à trouver la meilleure disposition des conteneurs dans les avions. Limbourg, Schyns et Laporte (2011) ont proposé un modèle à variables entières pour traiter les problèmes élémentaires. Notre travail est une extension de ces travaux. Nous considérons des chargements spéciaux qui impliquent des précautions particulières (produits dangereux, animaux, produits réfrigérés, aliments périssables, ...) ainsi que le transport de marchandises de plus grande taille. L’ajout de ces deux types de contraintes se justifie par la grande fréquence de ces situations dans des problèmes réels rencontrés par nos partenaires industriels. Le problème résultant est très complexe et nous proposons un outil pour le résoudre. [less ▲]

An Integer Programming model for air transport of hazardous and special shipments

Conference (2012, February 02)

The aircraft loading problem is a real-world combinatorial optimisation problem highly constrained. This weight must be distributed to keep the centre of gravity within speci ed limits. Moreover, an ... [more ▼]

The aircraft loading problem is a real-world combinatorial optimisation problem highly constrained. This weight must be distributed to keep the centre of gravity within speci ed limits. Moreover, an aircraft has usually several cargo compart- ments with speci c contours and structural limitations such as oor loading, com- bined load limits and cumulative load limitations. Finally, some shipments are par- ticularly restrictive to transport, like dangerous goods, live animals and perishable goods. This paper is concerned with the incorporation of these latter constraints in a mixed integer linear program for the problem of loading a set of Unit Load- ing Devices and bulk into an aircraft. Experimental results show that our method achieves optimal solutions within only few seconds. [less ▲]

Automatic Aircraft Load Planning

in Journal of the Operational Research Society (2012), 63

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 ... [more ▼]

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. [less ▲]

Three Dimensional Bin Packing Problem applied to air cargo

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 ▲]

Automatic Cargo Load Planning: Special shipments

Scientific conference (2011, May 25)

The aircraft loading problem is a real-world combinatorial optimisation problem highly constrained. Indeed, loading the aircraft so the gross weight is less than the maximum allowable is not enough. This ... [more ▼]

The aircraft loading problem is a real-world combinatorial optimisation problem highly constrained. Indeed, loading the aircraft so the gross weight is less than the maximum allowable is not enough. This weight must be distributed to keep the centre of gravity (CG) within specified limits. Moreover, an aircraft has usually several cargo compartments with specific contours and structural limitations such as floor loading, combined load limits and cumulative load limitations. Finally, some shipments are particularly restrictive to transport, like dangerous goods, live animals and perishable goods. This paper is concerned with the incorporation of these latter constraints in a mixed integer linear program for the problem of loading a set of Unit Loading Devices (ULDs) and bulk into an aircraft. Experimental results for real data sets show that the model achieves better balanced solutions in only a few seconds compared to the solution obtained by load masters. [less ▲]