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ORBi Open Repository and Bibliography (168.463 recursos)
In may 2007, the ULg's Administrative Board (joined in June 2007 by the FUSAGx) decided to create an institutional repository and defined a strong institutional self-archiving policy to increase the visibility, accessibility and impact of the University's publications (Board's decision). This decision led to the official launch, in November 2008, of the ORBi platform including both the Academic Bibliography and the Institutional Repository of the Wallonia-Europe University Academy.

Business & economic sciences => Quantitative methods in economics & management

Mostrando recursos 1 - 20 de 197

1. Quadratic reformulations of nonlinear binary optimization problems - Crama, Yves

2. Quadratic reformulations of nonlinear binary optimization problems - Crama, Yves

3. A new methodological approach for error distributions selection - Hambuckers, julien; Heuchenne, Cédric
Since 2008 and its financial crisis, an increasing attention has been devoted to the selection of an adequate error distribution in risk models, in particular for Value-at-Risk (VaR) predictions. We propose a robust methodology to select the most appropriate error distribution candidate, in a classical multiplicative heteroscedastic model. In a first step, unlike to the traditional approach, we do not use any GARCH-type estimation of the conditional variance. Instead, we propose to use a recently developed nonparametric procedure: the Local Adaptive Volatility Estimation (LAVE). The motivation for using this method is to avoid a possible model misspecification for the conditional variance. In a second...

4. A new methodological approach for error distributions selection - Hambuckers, julien; Heuchenne, Cédric
Peer reviewed

5. The Airline Container Loading Problem with Pickup and Delivery - Lurkin, Virginie; Schyns, Michael
The present paper looks into the problem of optimizing the loading of a set of containers and pallets into cargo aircraft serving multiple airports. Due to the pickup and delivery operations occurring at intermediate airports, this problem is simultaneously a weight and balance problem and a sequencing problem. Our objective is to minimize fuel and handling operations costs. This problem is shown to be NP-hard. We resort to a mixed integer linear program. On the basis of a professional partner's real-world data, TNT Airways, we perform numerical experiments using a standard B&C library. This approach yields better solutions than traditional manual planning, which results in substantial cost...

6. Quadratization of symmetric pseudo-Boolean functions - Anthony, Martin; Boros, Endre; Crama, Yves; Gruber, Aritanan
A pseudo-Boolean function is a real-valued function $f(x)=f(x_1,x_2,\ldots,x_n)$ of $n$ binary variables; that is, a mapping from $\{0,1\}^n$ to ${\bbr}$. For a pseudo-Boolean function $f(x)$ on $\{0,1\}^n$, we say that $g(x,y)$ is a quadratization of $f$ if $g(x,y)$ is a quadratic polynomial depending on $x$ and on $m$ auxiliary binary variables $y_1,y_2,\ldots,y_m$ such that $f(x)= \min \{ g(x,y) : y \in \{0,1\}^m \} $ for all $x \in \{0,1\}^n$. By means of quadratizations, minimization of $f$ is reduced to minimization (over its extended set of variables) of the quadratic function $g(x,y)$. This is of some practical interest because minimization of...

7. A Mixed Integer Programming formulation for the three dimensional bin packing problem deriving from an air cargo application - Paquay, Célia; Schyns, Michael; Limbourg, Sabine
Peer reviewed

8. Empty Container Management in the Benelux Waterways - Salmon, Frédéric; Limbourg, Sabine
Peer reviewed

9. Optimization model for empty container repositioning - Salmon, Frédéric; Limbourg, Sabine
Peer reviewed

10. Revealed preference tests of collectively rational consumption behavior: formulations and algorithms - Talla Nobibon, Fabrice; Cherchye, Laurens; Crama, Yves; Demuynck, Thomas; De Rock, Bram; Spieksma, Frits C.R.
This paper focuses on revealed preference tests of the collective model of household consumption. We start by showing that the decision problems corresponding to testing collective rationality are {\sc np}-complete. This makes the application of these tests problematic for (increasingly available) large(r) scale data sets. We then present two approaches to overcome this negative result. First, we introduce exact algorithms based on mixed-integer programming ({\sc mip}) formulations of the collective rationality tests, which can be usefully applied to medium sized data sets. Next, we propose simulated annealing heuristics, which allow for efficient testing of the collective model in the case...

11. The Airline Container Loading Problem with Pickup & Delivery and Multi Doors - Schyns, Michael; Lurkin, Virginie
Peer reviewed

12. A branch and price approach for an airport vehicle routing problem - Schyns, Michael
Peer reviewed

13. Etude d’impact de l’apprentissage par la vidéo et la radio rurale sur la transformation à petite échelle du riz local au Bénin - Zossou, Enangnon
La culture du riz a été reconnue par les Nations Unies comme l'une des principales sources de nourriture pouvant favoriser la sécurité alimentaire, l'éradication de la pauvreté et la réalisation à l'échelle internationale des objectifs du Millénaire. Au Bénin, beaucoup de réformes ont été faites dans la filière riz pour accroître la production nationale. La production et la transformation du riz sont des tâches souvent réparties sur la base du sexe avec les femmes en grande partie responsables des opérations post-récoltes. La transformation du riz au Bénin est généralement faite à petite échelle et constitue une source non négligeable de revenus. Dans le but d’améliorer l’apprentissage au...

14. Approximation Algorithms for Multi-Dimensional Vector Assignment Problems - Crama, Yves

15. Quadratic reformulations of nonlinear binary optimization problems - Crama, Yves
We consider the problem of minimizing a pseudo-Boolean function f(x), i.e., a real-valued function of 0-1 variables. Several authors have recently proposed to reduce this problem to the quadratic case by expressing f(x) as min{g(x,y): y in {0,1}}, where g is a quadratic function of x and of additional binary variables y. We establish lower and upper bounds on the number of additional y-variables needed in such a reformulation, both for the general case and for the special case of symmetricfunctions like positive or negative monomials, k-out-of-n majority functions, or parity functions.

16. Quadratization of pseudo-Boolean functions - Crama, Yves

17. An exact formulation for the three-dimensional bin-packing with transportation constraints - Paquay, Célia; Schyns, Michael; Limbourg, Sabine
Peer reviewed

18. Control Charts monitoring product’s loss to society - Celano, Giovanni; Faraz, Alireza; Saniga, Erwin
Peer reviewed

19. The determinants of charitable giving in Belgium - Mernier, Amélie; Dufays, Frédéric; Dal Fior, Catherine
Peer reviewed

20. The Airline Container Loading Problem with Pickup and Delivery - Lurkin, Virginie; Schyns, Michael
Peer reviewed

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