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QuantOM is open to every researcher working in the field of quantitative methods for management, logistics and operations management.
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Scientific Production
A subset of recent works published by QuantOM members is available through the institutional depository ORBi:
Papers  Books  Working Papers  Conferences
Papers in Journals
Bergeacyclic multilinear 01 optimization problemsBuchheim, Christoph; Crama, Yves; Rodriguez Heck, Elisabethin European Journal of Operational Research (2019), 273 The problem of optimizing a multilinear polynomial f in 0–1 variables arises in applications from many different areas. We are interested in resolution methods based on reformulating the polynomial ...
Revealed preference theory: An algorithmic outlookSmeulders, Bart; Crama, Yves; Spieksma, Frits C.R.in European Journal of Operational Research (2019), 272 Revealed preference theory is a domain within economics that studies rationalizability of behavior by (certain types of) utility functions. Given observed behavior in the form of choice data, testing ...
Seven Surveys in Operations ResearchCrama, Yves; Grabisch, Michel; Martello, Silvanoin Annals of Operations Research (2018), 271(1), The present issue collects seven surveys that appeared in the triennium 2015–2017 of 4OR: A Quarterly Journal of Operations Research. The authors of the surveys were given the opportunity to correct...
Modeling competition among airline itinerariesLurkin, Virginie; Garrow, Laurie A.; Higgins, Matthew J.; Newman, Jeffrey P; Schyns, Michaelin Transportation Research. Part A, Policy and Practice (2018), 113 Discrete choice models are commonly used to forecast the probability an airline passenger chooses a specific itinerary. In a prior study, we estimated an itinerary choice model based on a multinomial ...
Editorial: Sweet sixteenCrama, Yves; Grabisch, Michel; Martello, Silvanoin 4OR: A Quarterly Journal of Operations Research (2018) This is the traditional triennial note used by the editors to give the readers of 4OR information on the state of the journal and its future. In the 3years that have passed since the last editorial no...
Stochastic Inventory Routing for Perishable ProductsCrama, Yves; Rezaei Sadrabadi, Mahmood; Savelsbergh, Martin; Van Woensel, Tomin Transportation Science (2018), 52(3), 526546 Different solution methods are developed to solve an inventory routing problem for a perishable product with stochastic demands. The solution methods are compared empirically in terms of average profi...
Testing a Mixture Model of SinglePeaked PreferencesSmeulders, Bartin Mathematical Social Sciences (2018), 93 SinglePeaked preferences play an important role in the social choice literature. In this paper, we look at necessary and sufficient conditions for aggregated choices to be consistent with a mixture m...
Testing probabilistic models of choice using column generationTeSmeulders, Bart; DavisStober, Clintin; Regenwetter, Michel; Spieksma, Frits C.R.in Computers and Operations Research (2018) In socalled random preference models of probabilistic choice, a decision maker chooses according to an unspecified probability distribution over preference states. The most prominent case arises when...
Development, dissemination, and applications of a new terminological resource the QCode taxonomy for professional aspects of General Practice / Family Medicine.Jamoulle, Marc; Resnick, Melissa; Grosjean, Julien; Ittoo, Ashwin; Cardillo, Elena; Vander Stichele, Robert; Darmoni, Stefan; Vanmeerbeek, Marcin European Journal of General Practice (2017), accepted Abstract of Background Paper: Background: While documentation of clinical aspects of General Practice/Family Medicine (GP/FM) is assured by the International Classification of Primary Care (ICPC), the...
Analysis of definitions of General Practice/Family Medicine and Primary Health CareJamoulle, Marc; Resnick, Melissa; Ittoo, Ashwin; Cardillo, Elena; Vander Stichele, Robert; Vanmeerbeek, Marcin British Journal of General Practice (2017), 0050 Abstract Background There are numerous definitions of General Practice and Family Medicine (GP/FM) and Primary Health Care (PHC), but the distinction between the two concepts is unclear. Aim To conduc...
Early Detection of University Students with Potential DifficultiesHoffait, AnneSophie; Schyns, Michaelin Decision Support Systems (2017), 101 Using data mining methods, this paper presents a new means of identifying freshmen's profiles likely to face major difficulties to complete their first academic year. Academic failure is a relevant is...
Accounting for Price Endogeneity in Airline Itinerary Choice Models: An Application to Continental U.S. MarketsLurkin, Virginie; Garrow, Laurie; Higgins, Matthew; Newman, Jeffrey; Schyns, Michaelin Transportation Research. Part A, Policy and Practice (2017), 100 Network planning models, which forecast the profitability of airline schedules, support many critical decisions, including equipment purchase decisions. Network planning models include an itinerary ch...
A Machine LearningBased Approximation of Strong BranchingMarcos Alvarez, Alejandro; Louveaux, Quentin; Wehenkel, Louisin INFORMS Journal on Computing (2017), 29(1), 185195 We present in this paper a new generic approach to variable branching in branchandbound for mixed integer linear problems. Our approach consists in imitating the decisions taken by a good branching...
A road map for explorative scenario creation on Belgian rail freight transport developmentTroch, Franck; Vanelslander, Thierry; Sys, Christa; Laroche, Florent; Stevens, Vidar; Verhoest, Koen; Merchan Arribas, Angel; Mostert, Martine; Tawfik, Christine Maher Fouad; Belboom, Sandra; Léonard, Angélique; Limbourg, Sabinein Competition and Regulation in Network Industries (2017) 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 r...
Cellwise Robust regularized discriminant analysisAerts, Stéphanie; Wilms, Inesin Statistical Analysis and Data Mining (2017), 10 Quadratic and Linear Discriminant Analysis (QDA/LDA) are the most often applied classification rules under normality. In QDA, a separate covariance matrix is estimated for each group. If there are mor...
Guided Dive for the Spatial BranchandBoundGerard, Damien; Koeppe, Matthias; Louveaux, Quentinin Journal of Global Optimization (2017) We study the spatial BrandandBound algorithm for the global opti mization of nonlinear problems. In particular we are interested in a method to find quickly good feasible solutions. Most spatial Br...
Exact algorithms for the Equitable Traveling Salesman ProblemKinable, Joris; Smeulders, Bart; Delcour, Eline; Spieksma, Frits C.R.in European Journal of Operational Research (2017) Given a weighted graph G = (V,E), the Equitable Traveling Salesman Problem (ETSP) asks for two perfect matchings in G such that (1) the two matchings together form a Hamiltonian cycle in G and (2) the...
How can seed removal rates of zoochoric tree species be assessed quickly and accurately?Hambuckers, julien; Dauvrin, Alice; Trolliet, Franck; Evrard, Quentin; Forget, PierreMichel; Hambuckers, Alainin Forest Ecology and Management (2017), 403 The quantification of seed dispersal and predation processes has been gaining increased importance in the assessment of forest responses to anthropogenic disturbance, but also in developing an underst...
Integration of order picking and vehicle routing in a B2C ecommerce contextMoons, Stef; Ramaekers, Katrien; Caris, An; Arda, Yaseminin Flexible Services and Manufacturing Journal (2017) Ecommerce sales are increasing every year and customers who buy goods on the Internet have high service level expectations. In order to meet these expectations, a company’s logistics operations nee...
A Quantitative DoignonBellScarf theoremAliev, Iskander; Bassett, Robert; De Loera, Jesus; Louveaux, Quentinin Combinatorica (2017) The famous DoignonBellScarf theorem is a Hellytype result about the existence of integer solutions to systems of linear inequalities. The purpose of this paper is to present the following quantitat...
Quadratic reformulations of nonlinear binary optimization problemsAnthony, Martin; Boros, Endre; Crama, Yves; Gruber, Aritananin Mathematical Programming (2017), 162 Very large nonlinear unconstrained binary optimization problems arise in a broad array of applications. Several exact or heuristic techniques have proved quite successful for solving many of these pro...
Large neighborhood search for multitrip vehicle routingFrançois, Véronique; Arda, Yasemin; Crama, Yves; Laporte, Gilbertin European Journal of Operational Research (2016), 255(2), 422441 We consider the multitrip vehicle routing problem, in which each vehicle can perform several routes during the same working shift to serve a set of customers. The problem arises when customers are cl...
Editorial: A brand new cheating attempt: a case of usurped identityCrama, Yves; Grabisch, Michel; Martello, Silvanoin 4OR: A Quarterly Journal of Operations Research (2016), 14 We recall some cases of ethical misconduct that occurred in the recent years, and we report a new trick that was recently attempted to cheat the journal in order to obtain the publication of an articl...
The Robust Economic Statistical Design of the Hotelling’s T^2 ChartFaraz, Alireza; Chalaki, Kamyar; Saniga, Erwin; Heuchenne, Cédricin Communications in Statistics: Theory and Methods (2016) Economic statistical designs aim at minimizing the cost of process monitoring when a specific scenario or a set of estimated process and cost parameters is given. However, in practical situations the ...
Modeling in Air Transportation: Cargo Loading and Itinerary ChoiceLurkin, Virginiein 4OR: A Quarterly Journal of Operations Research (2016) This is a summary of the author's PhD thesis supervised by Michael Schyns and defended on April 29, 2016 at the University of Li\`ege, Belgium. We examine two problems as part of this dissertation. Th...
Conditional portfolio allocation: Does aggregate market liquidity matter?Bazgour, Tarik; Heuchenne, Cédric; Sougné, Daniellein Journal of Empirical Finance (2016), 35 This paper investigates how aggregate liquidity influences optimal portfolio allocations across various US characteristic portfolios. We consider shortterm allocation problems, with single and multip...
Designing an MOOC as an agentplatform aggregating heterogeneous virtual learning environmentsWautelet, Yves; Heng, Samedi; Kolp, Manuel; Penserini, Loris; Poelmans, Stephanin Behaviour and Information Technology (2016), 35(11), 980997 With the emergence of cloud technologies, on the one hand, and social networks, on the other hand, the possibilities for elearning have been drastically enhanced in the latest years. Virtual Learning...
Logistics Service Quality: The Case of Da Nang CityLimbourg, Sabine; Giang, Ho Thi Quynh; Cools, Marioin Procedia Engineering (2016), 142 Cost minimization is a key objective in managing logistics services. In this context, a growing interest in quality improvement can be observed. However, service quality is hard to quantify as it is a...
Quadratization of symmetric pseudoBoolean functionsAnthony, Martin; Boros, Endre; Crama, Yves; Gruber, Aritananin Discrete Applied Mathematics (2016), 203 A pseudoBoolean function is a realvalued 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 pseudoBoolean function $f(x)$ on $\{0,...
Multivariate coefficients of variation: Comparison and influence functionsAerts, Stéphanie; Haesbroeck, Gentiane; Ruwet, Christelin Journal of Multivariate Analysis (2015), 142 In the univariate setting, coeﬃcients of variation are wellknown and used to compare the variability of populations characterized by variables expressed in diﬀerent units or having really diﬀer...
An Ant Colony System for Responsive Dynamic Vehicle RoutingSchyns, Michaelin European Journal of Operational Research (2015), 245(3), 704718 We present an algorithm based on an Ant Colony System to deal with a broad range of Dynamic Capacitated Vehicle Routing Problems with Time Windows, (partial) Split Delivery and Heterogeneous fleets (D...
The Airline Container Loading Problem with Pickup and DeliveryLurkin, Virginie; Schyns, Michaelin European Journal of Operational Research (2015), 244(3), 955965 This paper considers the loading optimization problem for a set of containers and pallets transported into a cargo aircraft that serves multiple airports. Because of pickup and delivery operations tha...
The strength of multirow modelsLouveaux, Quentin; Poirrier, Laurent; Salvagnin, Domenicoin Mathematical Programming Computation (2015), 7(2), 113148 We develop a method for computing facetdefining valid inequalities for any mixedinteger set PJ. Our practical implementation does not return only facet defining inequalities, but it is able to find...
Valid inequalities for the single arc design problem with setupsAgra, Agostinho; Doostmohammadi, Mahdi; Louveaux, Quentinin Discrete Optimization (2015), 16 We consider a mixed integer set which generalizes two wellknown sets: the single node fixed charge network set and the single arc design set. Such set arises as a relaxation of feasible sets of gene...
Shewhart Control Charts for Monitoring Reliability with Weibull LifetimesFaraz, Alireza; Saniga, Erwin; Heuchenne, Cédricin Quality and Reliability Engineering International (2015), 31 In this paper, we present Shewhart type Z ̅ and S2 control charts for monitoring individual or joint shifts in the scale and shape parameters of a Weibull distributed process. The advantage of this m...
Vehicle routing problems with loading constraints: Stateoftheart and future directionsPollaris, Hanne; Braekers, Kris; Caris, An; Janssens, Gerrit K.; Limbourg, Sabinein OR Spectrum (2015), 37(Issue 2), 297330 Distributors are faced with loading constraints in their route planning, e.g.,multidimensional packing constraints, unloading sequence constraints, stability constraints and axle weight limits. Ignor...
Control Charts monitoring product’s loss to societyCelano, Giovanni; Faraz, Alireza; Saniga, Erwinin Quality and Reliability Engineering International (2014), 30(8), 13931407 Taguchi introduced a new philosophy in quality control that accounts for the economic loss associated to process variation measured by deviations from the target value of a product quality characteris...
Statistical performance of a control chart monitoring the ratio of two normal variablesCelano, Giovanni; CASTAGLIOLA, Philippe; Faraz, Alireza; Fichera, S.in Quality and Reliability Engineering International (2014), 30(8), 13611377 Online Statistical Process Control (SPC) monitoring the ratio Z of two normal variables X and Y has surprisingly received too little attention in the quality control literature. Several potential app...
Multiperiod vehicle loading with stochastic release datesArda, Yasemin; Crama, Yves; Kronus, David; Pironet, Thierry; Van Hentenryck, Pascalin EURO Journal on Transportation and Logistics (2014), 3(2), 93119 This paper investigates a multiperiod vehicle loading problem with stochastic information regarding the release dates of items to be transported. The deterministic version of the problem can be formu...
The variable parameters T2 chart with run rulesFaraz, Alireza; Celano, Giovanni; Heuchenne, Cédric; Saniga, Erwin; Fichera, S.in Statistical Papers (2014), 55(4), 933950 The Hotelling’s T2 control chart with variable parameters (VP T2) has been shown to have better statistical performance than other adaptive control schemes in detecting small to moderate process mea...
A learning procedure for sampling semantically different valid expressionsStPierre, David Lupien; Maes, Francis; Ernst, Damien; Louveaux, Quentinin International Journal of Artificial Intelligence (2014), 12(1), 1835 A large number of problems can be formalized as finding the best symbolic expression to maximize a given numerical objective. Most approaches to approximately solve such problems rely on random explor...
An algorithm for the separation of tworow cutsLouveaux, Quentin; Poirrier, Laurentin Mathematical Programming (2014), 143(12), 111146 We consider the question of finding deep cuts from a model with two rows of the type PI = {(x,s) ∈ Z2 ×Rn+ : x = f +Rs}. To do that, we show how to reduce the complexity of setting up the polar of ...
A combinatorial branchandbound algorithm for box searchMathieu, Sébastien; Louveaux, Quentinin Discrete Optimization (2014), 13 Considering a set of points in a multidimensional space with an associated real value for each point, we want to find the box with the maximum sum of the values of the included points. This problem h...
MultiDimensional Vector Assignment ProblemsDokka, Trivikram; Crama, Yves; Spieksma, Frits C.R.in Discrete Optimization (2014), 14 We consider a special class of axial multidimensional assignment problems called multi dimensional vector assignment (MVA) problems. An instance of the MVA problem is defined by m disjoint sets, eac...
Monitoring delivery chains using multivariate control chartsFaraz, Alireza; Heuchenne, Cédric; Saniga, Erwin; Foster, Earnestin European Journal of Operational Research (2013), 228(1), 282289 Delivery chains are concerned with the delivery of goods and services to customers within a specific time interval; this time constraint is added to the usual consumer demand for product or service qu...
Min max generalization for deterministic batch mode reinforcement learning: relaxation schemesFonteneau, Raphaël; Ernst, Damien; Boigelot, Bernard; Louveaux, Quentinin SIAM Journal on Control and Optimization (2013), 51(5), 33553385 We study the min max optimization problem introduced in Fonteneau et al. [Towards min max reinforcement learning, ICAART 2010, Springer, Heidelberg, 2011, pp. 61–77] for computing policies for batch...
Power indices and the measurement of control in corporate structuresCrama, Yves; Leruth, Lucin International Game Theory Review (2013), 15 This paper proposes a brief review of the use of power indices in the corporate governance literature. Without losing sight of the field of application, it places the emphasis on the gametheoretic as...
Investigation of advanced materials for fusion alpha particle diagnosticsBonheure, G.; Van Wassenhove, G.; Hult, M.; González de Orduña, R.; Strivay, David; Vermaercke, P.; Delvigne, T.; Chene, Grégoire; Delhalle, René; Huber, A.; Schweer, B.; Esser, G.; Biel, W.; Neubauer, O.in Fusion Engineering and Design (2013) Fusion alpha particle diagnostics for ITER remain a challenging task. Standard escaping alpha particle detectors in present tokamaks are not applicable to ITER and techniques suitable for fusion react...
A leaderfollower game in competitive facility locationKucukaydin, Hande; Aras, Necati; Altinel, I. Kubanin Computers and Operations Research (2012), 39(2), 437448 We address the problem of locating new facilities of a firm or franchise that enters a market where a competitor operates existing facilities. The goal of the new entrant firm is to decide the locatio...
Automatic Aircraft Load PlanningLimbourg, Sabine; Schyns, Michael; Laporte, Gilbertin 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 r...
A Meta Model to Optimally Design the VSI T2 Control ChartFaraz, Alireza; Seif, A.in International Journal of Applied Operational Research (2012), 1(3), 5369 Recent studies have shown that the variable sampling interval (VSI) scheme helps practitioners to detect process shifts more quickly than the classical scheme (FRS). In this paper, the economically an...
A heuristic method to schedule training programs for Small and Medium EnterprisesRezaei Sadrabadi, Mahmood; Shamsaei, Fahimeh; Mohammadian, Iman; van Vyve, Mathieuin European Journal of Operational Research (2012), 217 During the life period of Small and Medium Enterprises (SMEs) in incubators they need some training programs to acquire the required knowledge in order to survive and succeed in the business environme...
The interval ordering problemDurr, Christophe; Queyranne, Maurice; Spieksma, Frits C.R.; Talla Nobibon, Fabrice; Woeginger, Gerhard J.in Discrete Applied Mathematics (2012)
Statistical Merits and Economic Evaluation of T2 Control Charts with the VSSC SchemeSeif, Asghar; Moghadam, M.B.; Faraz, Alireza; Heuchenne, Cédricin Arabian Journal for Science and Engineering (2011), 36(7), 14611470 T2 control charts are used to monitor a process when more than one quality variable associated with the process is being observed. Recent studies have shown that using variable sampling size (VSS) sch...
Split rank of triangle and quadrilateral inequalitiesDey, Santanu; Louveaux, Quentinin Mathematics of Operations Research (2011), 36(3), 432461 A simple relaxation of two rows of a simplex tableau is a mixed integer set consisting of two equations with two free integer variables and nonnegative continuous variables. Recently Andersen et al. ...
Economic Statistical Design of a T2 Control Chart with Double Warning LinesFaraz, Alireza; Saniga, Erwinin Quality and Reliability Engineering International (2011), 27(2), 125139 Recent studies have shown that enhancing the common T2 control chart by using variable sample sizes (VSS) and variable sample intervals (VSI) sampling policies with a double warning line scheme (DWL) ...
Facility location via fuzzy modeling and simulationRezaei Sadrabadi, Mahmood; Fazel Zarandi, M. H.in Applied Soft Computing (2011), 11(8), 53305340 This paper presents a continuous facility location model with fuzzy methodology. The developments concern mainly to some drawbacks in the initial model which takes it far from being used in practice. ...
A discrete competitive facility location model with variable attractivenessKucukaydin, Hande; Aras, Necati; Altinel, I. Kubanin Journal of the Operational Research Society (2011), 62(9), 17261741 We consider the discrete version of the competitive facility location problem in which new facilities have to be located by a new market entrant firm to compete against already existing facilities tha...
Coloring Graphs Using Two Colors while Avoiding Monochromatic CyclesTalla Nobibon, Fabrice; Hurkens, Cor A. J.; Leus, Roel; Spieksma, Fritsin INFORMS Journal on Computing (2011) We consider the problem of deciding whether a given directed graph can be vertex partitioned into two acyclic subgraphs. Applications of this problem include testing rationality of collective consumpt...
Improving Product Quality and Reliability with Customer Experience DataBrombacher, Aarnout; Hopma, Eva; Ittoo, Ashwin; Lu, Yuan; Luyk, Ilse; Maruster, Laura; Ribeiro, Joel; Weijters, Ton; Wortmann, Hansin Quality and Reliability Engineering International (2011), 28(8), 873886
Logical Analysis of Data: Classification with justificationBoros, Endre; Crama, Yves; Hammer, Peter L.; Ibaraki, Toshihide; Kogan, Alexander; Makino, Kazuhisain Annals of Operations Research (2011), 188 Learning from examples is a frequently arising challenge, with a large number of algorithms proposed in the classification, data mining and machine learning literature. The evaluation of the quality o...
ECONOMICALLY DESIGNED HOTELLING’S T2 CONTROL CHART USING VSICL SCHEMEtorabian, Mohsen; Moghadam, M. B.; Faraz, Alirezain Arabian Journal for Science and Engineering (2010), 35(2), 251263 The Hotelling’s T2 control chart, is the most widely used multivariate procedure for two or more related quality characteristics, but it’s power lacks the desired performance in detecting small to...
An application of fuzzy random variables to control chartsFaraz, Alireza; Shapirob, Arnoldin Fuzzy Sets and Systems (2010), 161(20), 26842694 The two most significant sources of uncertainty are randomness and incomplete information. In real systems, we wish to monitor processes in the presence of these two kinds of uncertainty. This paper a...
Space and time allocation in a shipyard assembly hallBay, Maud; Crama, Yves; Langer, Yves; Rigo, Philippein Annals of Operations Research (2010), 179(1), 5776 We present a space and time allocation problem that arises in assembly halls producing large building blocks (namely, a shipyard which assembles prefabricated keel elements). The building blocks are v...
Mixedinteger sets from two rows of two adjacent simplex basesAndersen, Kent; Louveaux, Quentin; Weismantel, Robertin Mathematical Programming (2010), 124(12), 455480 In 2007 we studied a mixedinteger set arising from two rows of a simplex tableau. We showed that facets of such a set can be obtained from lattice point free triangles and quadrilaterals associated w...
RelaxMCD: smooth optimisation for the Minimum Covariance Determinant estimatorSchyns, Michael; Haesbroeck, Gentiane; Critchley, Frankin Computational Statistics and Data Analysis (2010), 54(4), 843857 The Minimum Covariance Determinant (MCD) estimator is a highly robust procedure for estimating the center and shape of a high dimensional data set. It consists of determining a subsample of h points o...
A relaxed approach to combinatorial problems in robustness and diagnosticsCritchley, Frank; Schyns, Michael; Haesbroeck, Gentiane; Fauconnier, Cécile; Lu, Guobing; Atkinson, Richard A; Wang, Dong Quianin Statistics and Computing (2010), 20(1), 99115 A range of procedures in both robustness and diagnostics require optimisation of a target functional over all subsamples of given size. Whereas such combinatorial problems are extremely difficult to s...
On Vershikian and Icosy random variables and filtrationsLaurent, Stéphanein Teoriya Veroyatnostei i ee Primeneniya (2010), 55 We prove that the equivalence between Vershik’s standardness criterion and the Icosiness criterion for a filtration in discrete, negative time, holds separately for each random variable. This gives...
On standardness and IcosinessLaurent, Stéphanein Séminaire de Probabilités (2010), XLIII The object of study of this work is the invariant characteristics of filtrations in discrete, negative time, pioneered by Vershik. We prove the equivalence between Icosiness and standardness without ...
The Optimal Design of the VSI T2 Control ChartFaraz, Alireza; Kazemzadeh, R. B.; Heuchenne, Cédric; Saniga, Erwinin Journal of Iranian Statistical Society (2010), 9(1), 119 Recent studies have shown that the variable sampling interval (VSI) scheme helps practitioners detect process shifts more quickly than the classical scheme (FRS). In this paper, the economically and s...
A robust heuristic for the optimal selection of a portfolio of stocksSchyns, Michaelin International Journal of Operational Research (2010), 9(3), 258271 This paper introduces a new optimization heuristic for the robustification of critical inputs under consideration in many problems. It is shown that it allows to improve significantly the quality and ...
Hotelling’s T 2 control chart with two adaptive sample sizesFaraz, Alireza; Moghadam, M. B.in Quality and Quantity (2009), 43 Some quality control schemes have been developed when several related quality characteristics are to be monitored. The familiar multivariate process monitoring and control procedure is the Hotelling...
Hotelling’s T2 control chart with two adaptive sample sizesFaraz, Alireza; Moghadam, M. B.in Quality and Quantity (2009), 43(6), 903913 Some quality control schemes have been developed when several related quality characteristics are to be monitored. The familiar multivariate process monitoring and control procedure is the Hotelling...
Optimal railroad container terminal locations on the European networkLimbourg, Sabine; Jourquin, Bartin Transportation Research. Part E, Logistics and Transportation Review (2009), 45(4), 551563 The European transport policy has focused on sustainable transport solutions, among which intermodal transport is a key player. However, its efficiency is strongly dependent on the location of the con...
Certificates of linear mixed integer infeasibilityAndersen, Kent; Louveaux, Quentin; Weismantel, Robertin Operations Research Letters (2008), 36(6), 734738 We derive a certificate of integral infeasibility for linear systems with equations and inequalities by generating algebraically an outer description of a lattice point free polyhedron that contains t...
Polyhedral properties for the intersection of two knapsacksLouveaux, Quentin; Weismantel, Robertin Mathematical Programming (2008), 113(1), 1537 We address the question to what extent polyhedral knowledge about individual knapsack constraints suffices or lacks to describe the convex hull of the binary solutions to their intersection. It turns ...
Intermediate integer programming representations using value disjunctionsKöppe, Matthias; Louveaux, Quentin; Weismantel, Robertin Discrete Optimization (2008), 5(2), 293313 We introduce a general technique to create an extended formulation of a mixedinteger program. We classify the integer variables into blocks, each of which generates a finite set of vector values. The...
Supply chain coordination: A gametheory approachHennet, JeanClaude; Arda, Yaseminin Engineering Applications of Artificial Intelligence (2008), 21 In a supply chain organized as a network of autonomous enterprises, the main objective of each partner is to optimize his production and supply policy with respect to his own economic criterion. Confl...
Geršgorin variations III: On a theme of Brualdi and VargaBoros, Endre; Brualdi, Richard; Crama, Yves; Hoffman, Alanin Journal of Linear Algebra and its Applications (2008), 428 Brualdi brought to Geršgorin Theory the concept that the digraph G(A) of a matrix A is important in studying whether A is singular. He proved, for example, that if, for every directed cycle of G(A), ...
Counting and enumerating aggregate classifiersAdem, Jan; Crama, Yves; Gochet, Willy; Spieksma, Frits C.R.in Discrete Applied Mathematics (2008), 156(3), 24592468 We propose a generic model for the "weighted voting" aggregation step performed by several methods in supervised classification. Further, we construct an algorithm to count the number of dis...
The tool switching problem revisitedCrama, Yves; Moonen, Linda S; Spieksma, Frits CR; Talloen, Ellenin European Journal of Operational Research (2007), 182(2), 952957 In this note we study the tool switching problem with nonuniform tool sizes. More specifically, we consider the problem where the job sequence is given as part of the input. We show that the resultin...
Inequalities from two rows of the simplex tableauAndersen, Kent; Louveaux, Quentin; Weismantel, Robert; Wolsey, Laurence A.in Lecture Notes in Computer Science (2007) In this paper we explore the geometry of the integer points in a cone rooted at a rational point. This basic geometric object allows us to establish some links between lattice point free bodies and th...
Multiplicity and complexity issues in contemporary production schedulingBrauner, Nadia; Crama, Yves; Grigoriev, Alexander; van de Klundert, Jorisin Statistica Neerlandica (2007), 61(1), 7591 High multiplicity scheduling problems arise naturally in contemporary production settings where manufacturers combine economies of scale with high product variety. Despite their frequent occurrence in...
Fuzzy Control Chart A Better Alternative for Shewhart Average ChartFaraz, Alireza; MOGHADAM, M. B.in Quality and Quantity (2007), 41(3), 375385 This paper through a real illustrative example and a power test shows that designing a fuzzy control chart for process average of a continuous (variable) quality characteristic with a warning line is ...
Nonlinear regression with censored dataHeuchenne, Cédric; Van Keilegom, Ingridin Technometrics (2007), 49(1), 3444 Suppose that the random vector (X, Y) satisfies the regression model Y = m(X) + sigma(X)epsilon, where m(.) = E(Y vertical bar.) belongs to some parametric class (m(theta)(.):theta is an element of Th...
Location estimation in nonparametric regression with censored dataHeuchenne, Cédric; Van Keilegom, Ingridin Journal of Multivariate Analysis (2007), 98(8), 15581582 Consider the heteroscedastic model Y =m (X) +sigma(X)epsilon, where epsilon and X are independent, Y is subject to right censoring, m (center dot) is an unknown but smooth location function (like e.g....
Hotelling's T 2 control chart with double warning linesFaraz, Alireza; Parsian, Ahmadin Statistical Papers (2006), 47(4), 569593 Recent studies have shown that the T 2 control chart with variable sampling intervals (VSI) and/or variable sample sizes (VSS) detects process shitis faster than the traditional T 2 chart. This articl...
Inventory control in a multisupplier systemArda, Yasemin; Hennet, JeanClaudein International Journal of Production Economics (2006), 104 An enterprise network is analyzed from the viewpoint of an endproduct manufacturer who receives customer orders and organises his production and supply policy so as to minimize the sum of his average...
Optimization of Surface Utilization Using Heuristic ApproachesLanger, Yves; Bay, Maud; Crama, Yves; Bair, Frédéric; Caprace, JeanDavid; Rigo, Philippein Ship Technology Research (2005), 52(3), 141147 We present a scheduling problem that arises in factories producing large building blocks. This is a three dimensional binpacking problem with two spatial dimensions and a time dimension. We propose a...
A framework for the complexity of highmultiplicity scheduling problemsBrauner, Nadia; Crama, Yves; Grigoriev, Alexander; van de Klundert, Jorisin Journal of Combinatorial Optimization (2005), 9(3), 313323 The purpose of this note is to propose a complexity framework for the analysis of high multiplicity scheduling problems. Part of this framework relies on earlier work aiming at the definition of outpu...
Consensus algorithms for the generation of all maximal bicliquesAlexe, Gabriela; Alexe, Sorin; Crama, Yves; Foldes, Stephan; Hammer, Peter L.; Simeone, Brunoin Discrete Applied Mathematics (2004), 145(1 Sp. Iss. SI), 1121 We describe a new algorithm for generating all maximal bicliques (i.e. complete bipartite. not necessarily induced subgraphs) of a graph. The algorithm is inspired by, and is quite similar to. the con...
The maximum deviation justintime scheduling problemBrauner, Nadia; Crama, Yvesin Discrete Applied Mathematics (2004), 134(13), 2550 This note revisits the maximum deviation justintime (MDJIT) scheduling problem previously investigated by Steiner and Yeomans. Its main result is a set of algebraic necessary and sufficient conditio...
Extended formulations for Gomory Corner polyhedraKöppe, Matthias; Louveaux, Quentin; Weismantel, Robert; Wolsey, Laurence A.in Discrete Optimization (2004), 1(2), 141165 We present several types of extended formulations for integer programs, based on irreducible integer solutions to Gomory’s group relaxations. We present algorithmic schemes based on an iterative ref...
Simulated annealing for complex portfolio selection problemsCrama, Yves; Schyns, Michaelin European Journal of Operational Research (2003), 150(3), 546571 This paper describes the application of a simulated annealing approach to the solution of a complex portfolio selection model. The model is a mixed integer quadratic programming problem which arises w...
Approximation algorithms for the design of SDH/SONET networksBrauner, Nadia; Crama, Yves; Finke, Gerd; Lemaire, Pierre; Wynants, Christellein RAIRO: Recherche Opérationnelle (2003), 37(4, OCTDEC), 235247 In this paper, a graph partitioning problem that arises in the design of SONET/SDH networks is defined and formalized. Approximation algorithms with performance guarantees are presented. To solve this...
Production planning problems in printed circuit board assemblyCrama, Yves; van de Klundert, Joris; Spieksma, Frits CRin Discrete Applied Mathematics (2002), 123(13), 339361 This survey describes some of the main optimization problems arising in the context of production planning for the assembly of printed circuit boards. The discussion is structured around a hierarchica...
Cyclic scheduling in robotic flowshopsCrama, Yves; Kats, Vladimir; Van de Klundert, Joris; Levner, Eugenein Annals of Operations Research (2000), 96 Fully automated production cells consisting of flexible machines and a material handling robot have become commonplace in contemporary manufacturing systems. Much research on scheduling problems arisi...
Boolean normal forms, shellability and reliability computationsBoros, Endre; Crama, Yves; Ekin, Oya; Hammer, Peter L.; Ibaraki, Toshihide; Kogan, Alexin SIAM Journal on Discrete Mathematics (2000), 13 Orthogonal forms of positive Boolean functions play an important role in reliability theory, since the probability that they take value 1 can be easily computed. However, few classes of disjunctive no...
Cyclic scheduling in 3machine robotic flow shopsCrama, Yves; Van de Klundert, Jorisin Journal of Scheduling (1999), 2 We consider a robotic flow shop model in which a single robot is responsible for the transportation of parts between machines. For reasons of simplicity, when the shop is to produce a large number of ...
Hitting or avoiding balls in Euclidean spaceCrama, Yves; Ibaraki, Toshihidein Annals of Operations Research (1997), 69 We investigate the algorithmic complexity of several geometric problems of the following type: given a "feasible" box and a collection of balls in Euclidean space, find a feasible point whic...
Cyclic scheduling of identical parts in a robotic cellCrama, Yves; Van de Klundert, Jorisin Operations Research (1997), 45 We consider a robotic flowshop in which one type of product is to be repeatedly produced and where transportation of the parts between the machines is performed by the robot. The identical parts cycli...
Recherche opérationnelle et gestion de la productionCrama, Yves; Dupont, Lionel; Finke, Gerdin Nouvelles de la Science et des Technologies (1997), 15 Depuis leurs origines, la recherche opérationnelle et la gestion de la production entretiennent des relations privilégiées. Historiquement, la gestion de la production et les domaines connexes de l...
Variable and term removal from Boolean formulaeCrama, Yves; Ekin, Oya; Hammer, Peter L.in Discrete Applied Mathematics (1997), 75 Given a Boolean formula in disjunctive normal form, the variable deletion control set problem consists in finding a minimum cardinality set of variables whose deletion from the formula results in a DN...
Models for machinepart grouping in cellular manufacturingCrama, Yves; Oosten, Maartenin International Journal of Production Research (1996), 34 For cellular manufacturing strategies to succeed, the productive system first has to be divided into highly independent cells. This means that a partition of the machines into machine groups, a partit...
The component retrieval problem in printed circuit board assemblyCrama, Yves; Flippo, Olaf E.; Van de Klundert, Joris; Spieksma, Frits C.R.in International Journal of Flexible Manufacturing Systems (1996), 8 The minimization of the makespan of a printed circuit board assembly process is a complex problem. Decisions involved in this problem concern the specification of the order in which components are to ...
Complexity of product positioning and ball intersection problemsCrama, Yves; Hansen, Pierre; Jaumard, Brigittein Mathematics of Operations Research (1995), 20 The product positioning problem consists in choosing the attributes of a new product in such a way as to maximize its market share, i.e., to attract a maximum number of customers. Mathematically, the ...
Surface pressure in SOS modelsDe Coninck, Joël; Limbourg, Sabine; Newman, Charlesin Thin Solid Films (1994), 244 Microscopic models of the solidonsolid type were considered to describe the surface pressure of monolayers and bilayers on top of another layer in two and three dimensions. The two interfaces, above...
A complexity index for satisfiability problemsBoros, Endre; Crama, Yves; Hammer, Peter L.; Saks, Mikein SIAM Journal on Computing (1994), 23 This paper associates a linear programming problem (LP) to any conjunctive normal form p, and shows that the optimum value Z(p) of this LP measures the complexity of the corresponding SAT (Boolean sat...
Minimizing the number of tool switches on a flexible machineCrama, Yves; Kolen, Anton W.J.; Oerlemans, Alwin G.; Spieksma, Frits C.R.in International Journal of Flexible Manufacturing Systems (1994), 6 This article analyzes a tool switching problem arising in certain flexible manufacturing environments. A batch of jobs have to be successively processed on a single flexible machine. Each job requires...
Concave extensions for nonlinear 01 maximization problemsCrama, Yvesin Mathematical Programming (1993), 61 A wellknown linearization technique for nonlinear 01 maximization problems can be viewed as extending any polynomial in 01 variables to a concave function defined on [0, 1]. Some properties of this...
Chvátal cuts and odd cycle inequalities in quadratic 01 optimizationBoros, Endre; Crama, Yves; Hammer, Peter L.in SIAM Journal on Discrete Mathematics (1992), 5 In this paper a new lower bound for unconstrained quadratic 01 minimization is investigated. It is shown that this bound can be computed by solving a linear programming problem of polynomial size in ...
Detection of spurious states of neural networksCrama, Yves; Hansen, Pierre; Jaumard, Brigittein IEEE Transactions on Neural Networks (1991), 2 The authors study the complexity and propose an algorithm for the problem of determining, given p vectors of {1,1}^n, all linear combinations of them which are also in {1,1}^n. Computational results...
The basic algorithm for pseudoBoolean programming revisitedCrama, Yves; Hansen, Pierre; Jaumard, Brigittein Discrete Applied Mathematics (1990), 29 The basic algorithm of pseudoBoolean programming due to Hammer and Rudeanu allows to minimize nonlinear 0–1 functions by recursively eliminating one variable at each iteration. We show it has linea...
Upperbounds for quadratic 01 maximizationBoros, Endre; Crama, Yves; Hammer, Peter L.in Operations Research Letters (1990), 9 In this paper, three different approaches are generalised to obtain upper bounds for the maximum of a quadratic pseudoBoolean function f over [0,1]^n. The original approaches (complementation, majori...
More characterizations of triangulated graphsBenzaken, Claude; Crama, Yves; Duchet, Pierre; Hammer, Peter L.; Maffray, Frédéricin Journal of Graph Theory (1990), 14(4), 413422 New characterizations of triangulated and cotriangulated graphs are presented. Cotriangulated graphs form a natural subclass of the class of strongly perfect graphs, and they are also characterized in...
Bimatroidal independence systemsCrama, Yves; Hammer, Peter L.in Zeitschrift für operations research (1989), 33 An independence system Σ=(X, F) is called bimatroidal if there exist two matroids M=(X,FM) and N=(X,FN) such that F=FM∪FN. When this is the case, {M,N} is called a bimatroidal decomposition of Σ. ...
Causeeffect relationships and partially defined Boolean functionsCrama, Yves; Ibaraki, Toshihidein Annals of Operations Research (1988), 16 This paper investigates the use of Boolean techniques in a systematic study of causeeffect relationships. The model uses partially defined Boolean functions. Procedures are provided to extrapolate fr...
Dualization of regular boolean functionsCrama, Yvesin Discrete Applied Mathematics (1987), 16 A monotonic Boolean function is regular if its variables are naturally ordered by decreasing ‘strength’, so that shifting to the right the nonzero entries of any binary false point always yields ...
Strong unimodularity for matrices and hypergraphsCrama, Yves; Hammer, Peter L.; Ibaraki, Toshihidein Discrete Applied Mathematics (1986), 15 A 0–1 matrix A is called strongly unimodular if all the bases of (A, I) are triangular. We develop equivalent conditions for strong unimodularity, first in algebraic, then in graph theoretic terms. ...
Papers  Books  Working Papers  Conferences
Books and chapters of books
Optimisation des transports : de la mer à la terreLimbourg, Sabinein Lihoussou, Messan; Steck, Benjamin (Eds.) Moderniser les ports ouestafricains. Enjeux et perspectives. (2018) Operations research (OR) is a quantitative approach that uses advanced analytical methods to help managers make better decisions. The application of its techniques to freight transport and supply chai...
Design Patterns for Social Intelligent Agent Architectures ImplementationKolp, Manuel; Wautelet, Yves; Heng, Samediin Handbook of Research on Investigations in Artificial Life Research and Development (2018) Multiagent systems (MAS) architectures are popular for building open, distributed, and evolving software required by today's business IT applications such as ebusiness systems, web services, or ente...
Railroad terminals location with interconnected rail network of West African countriesLIHOUSSOU, Messan; Limbourg, Sabinein Cools, Mario; Limbourg, Sabine (Eds.) Proceedings of the BIVECGIBET Transport Research Days 2017: Towards an Autonomous and Interconnected Transport Future (2017) From 2006 to 2012, the port of Cotonou improves its performance thanks to the Millennium Challenge Account program, through modernization of port facilities and management systems. But the project not...
Building an Effective Strategy To Supply High Frequency Stores in Emerging CitiesSabiri, Asmaa; Riane, Fouad; Limbourg, Sabinein Cools, Mario; Limbourg, Sabine (Eds.) Proceedings of the BIVECGIBET Transport Research Days 2017: Towards an Autonomous and Interconnected Transport Future (2017) Traditional distribution channels that cover nanostores still abound in merging megacities. These traditional retail formats need to be visited and supplied very frequently (High Frequency Stores) whi...
The Fleet Size and Mix Vehicle Routing Problem with sequencebased pallet loading and axle weight constraintsPollaris, Hanne; Braekers, Kris; caris, An; Janssens, Gerrit, K.; Limbourg, Sabinein Cools, Mario; Limbourg, Sabine (Eds.) Proceedings of the BIVECGIBET Transport Research Days 2017: Towards an Autonomous and Interconnected Transport Future (2017) In this paper, the Fleet Size and Mix Vehicle Routing Problem (FSM) with sequencebased pallet loading and axle weight constraints is introduced. The effect of the integration of axle weight constrain...
De nouveaux terminaux à conteneurs en Belgique : hasard ou nécessité ?Jourquin, Bart; Limbourg, Sabinein Reflets et perspectives de la vie économique (2017) En parodiant le titre d’un célèbre essai de Jacques Monod (1971), cet article tente de synthétiser un certain nombre de travaux de recherche qui, ces dernières années, ont examiné la pertinenc...
Characteristics of Economically Designed CUSUM and \bar{X} Control ChartsSaniga, Erwin; Davis, Darwin; Faraz, Alireza; McWilliams, Thomas; Lucas, Jamesin Knoth, Sven; Schmid, Wolfgang (Eds.) Frontiers in Statistical Quality Control 11 (2015) In this paper we investigate the characteristics of economic control chart designs for both Shewhart (¯X ) and CUSUM control charts. Authors in the past have made some suggestions regarding the desig...
Optimally Locating Facilities with Variable CharacteristicsKucukaydin, Hande; Altinel, I. Kuban; Aras, NecatiBook published by LAP Lambert Academic Publishing (2012) The main focus of this study is on competitive facility location problems which constitute a special family of facility location problems. In such a problem, a firm or franchise is concerned with inst...
Automatic Cargo Load Planning: Special shipmentsLimbourg, Sabine; Schyns, Michaelin Cornelis, Eric (Ed.) Proceedings of the BIVECGIBET Transport Research Day 2011 (2011) The aircraft loading problem is a realworld combinatorial optimisation problem highly constrained. Indeed, loading the aircraft so the gross weight is less than the maximum allowable is not enough. T...
Boolean Functions: Theory, Algorithms, and ApplicationsCrama, Yves; Hammer, Peter L.Book published by Cambridge University Press (2011) This monograph provides the first comprehensive presentation of the theoretical, algorithmic and applied aspects of Boolean functions, i.e., {0,1}valued functions of a finite number of {0,1}valued v...
Modèles mathématiques en gestionBair, Jacques; Crama, Yves; Henry, Valérie; Justens, DanielBook published by Cassini et POLE (2011) Mis au point notamment pour la gestion de très grands projets industriels, les modèles mathématiques se sont imposés à tous les niveaux de l’activité économique : production, distribution et ...
Liftandproject inequalitiesLouveaux, Quentinin Wiley Encylopedia of Operations Research and Management Science (2011) The liftandproject technique is a systematic way to generate valid inequalities for a mixed binary program. The technique is interesting both on the theoretical and on the practical point of view. O...
The Mathematics of Peter L. Hammer (19362006): Graphs, Optimization, and Boolean ModelsBoros, Endre; Crama, Yves; De Werra, Dominique; Hansen, Pierre; Maffray, Frédéricin Boros, Endre; Crama, Yves; De Werra, Dominique; Hansen, Pierre; Maffray, Frédéric; Simeone, Bruno (Eds.) The Mathematics of Peter L. Hammer (19362006): Graphs, Optimization, and Boolean Models (2011) This volume of the Annals of Operations Research, contains a collection of papers published in memory of Peter L. Hammer. As we recall further down, Peter made substantial contributions to several are...
Nonparametric Mean Preservation in Censored RegressionHeuchenne, CédricBook published by VDM Verlag (2009) The aim of this book is to estimate the conditional mean of some functions depending on the response variable Y (moments, distributions...) in regression models where this response is possibly censore...
Modèles et données dans l’univers économiqueBair, Jacques; Crama, Yvesin Justens, Daniel (Ed.) Attentes d'un modèle (2008) Dans cette note, nous émettons quelques réflexions relatives à la modélisation scientifique, en insistant sur la spécificité de l'exploitation de modèles dans les sciences humaines, en particul...
Intermodal freight terminal location in Europe : a strategic modelJourquin, Bart; Limbourg, Sabinein Proceedings of the BIVECGIBET, Transport Research Day 2007 (2007) The political pressure in favour of multi and intermodal transport has oriented the focus on sustainable transport solutions. Intermodal transport is one of the possible solutions, but its efficien...
Corporate control concentration measurement and firm performanceCrama, Yves; Leruth, Luc; Renneboog, Luc; Urbain, JeanPierrein Batten, J.A.; Fetherston, T.A. (Eds.) Social Responsibility: Corporate Governance Issues (2003) Traditionally share price returns and their variance have been explained by factors linked to the operations of the company such as systematic risk, corporate size and P/E ratios or by factors related...
Visualizing Statistical Models and ConceptsFarebrother, Robert W.; Schyns, MichaelBook published by Marcel Dekker, Inc (2002) This text/reference examines classic algorithms, geometric diagrams, and mechanical principles for enhanced visualization of statistical estimation procedurs and mathematical concepts in physics, engi...
PseudoBoolean optimizationCrama, Yves; Hammer, Peter L.in Resende, M.G.C.; Pardalos, P.M. (Eds.) Handbook of Applied Optimization (2002) This article briefly surveys some fundamental results regarding pseudoBoolean functions....
Théorie stochastique de la décision d'investissementJustens, Daniel; Schyns, MichaelBook published by De Boeck & Larcier (1997) La complexité, l'imprévisibilité croissantes de l'environnement et de la structure interne des entreprises contraignent le gestionnaire à tendre vers une description probabiliste de l'univers. Le ...
Robotic flowshop scheduling is strongly NPcompleteCrama, Yves; Van de Klundert, Jorisin Klein Haneveld, W.K.; Vrieze, O.J.; Kallenberg, L.C.M. (Eds.) Ten Years LNMB (1997) We consider a robotic flowshop model in which a single robot is responsible for the transportation of parts between machines and the amount of time that a part spends on a machine must be comprised in...
Local search in combinatorial optimizationCrama, Yves; Kolen, Anton W.J.; Pesch, Erwinin Braspenning, P.J.; Thuijsman, F.; Weijters, A.J.M.M. (Eds.) Artificial Neural Networks : An Introduction to ANN Theory and Practice (1995)
Papers  Books  Working Papers  Conferences
Working papers, reports, thesis
Neighborhood Search Algorithms for MultiTrip Vehicle RoutingFrançois, VéroniqueDoctoral thesis (2018) Think about the lines of trucks we overtake on highways. Each of these trucks is performing a journey that may include several delivery or pickup operations before getting to a depot. And each of thes...
Inventory routing for perishable productsRezaei Sadrabadi, MahmoodDoctoral thesis (2016) We explore three problems in this thesis and develop solution methods for each problem. First, an inventory routing problem for a perishable product with stochastic demands is considered and different...
The np Control Charts with the Guaranteed InControl PerformanceFaraz, Alireza; Heuchenne, CédricEprint/Working paper (2016) In this paper, we evaluate the incontrol performance of npcontrol charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired...
Early Detection of University Students in Potential DifficultyHoffait, AnneSophie; Schyns, MichaelEprint/Working paper (2016) Using data mining methods, this paper presents a new means of identifying freshmen's profiles likely to face major difficulties to complete their first academic year. Academic failure is a relevant is...
A Comparison of Departure Time of Day FormulationsLurkin, Virginie; Garrow, Laurie; Higgins, Matthew; Newman, Jeffrey; Schyns, MichaelEprint/Working paper (2016) Airline passengers’ itinerary choices are influenced by many factors including carriers, prices, the number of connections, and departure times. This paper compares three different methods that have...
Nonparametric control charts: economic statistical designMarcos Alvarez, Alejandro; Heuchenne, Cédric; Faraz, AlirezaEprint/Working paper (2016) This paper studies economic statistical designs (ESD) for nonparametric control charts based on the sign and Wilcoxon tests. The main advantage of the procedures is that, except for the tested locatio...
Online Learning for Strong Branching Approximation in BranchandBoundMarcos Alvarez, Alejandro; Wehenkel, Louis; Louveaux, QuentinEprint/Working paper (2016) We present an online learning approach to variable branching in branchandbound for mixedinteger linear problems. Our approach consists in learning strong branching scores in an online fashion and i...
Feasibilityoriented Branching Strategies for Global OptimizationGerard, Damien; Köppe, Matthias; Louveaux, QuentinEprint/Working paper (2016) We study the spatial BrandandBound algorithm for the global optimization of nonlinear problems. In particular we are interested in a method to find quickly good feasible solutions. Most spatial Bran...
Large neighborhood search for multitrip vehicle routingFrançois, Véronique; Arda, Yasemin; Crama, Yves; Laporte, GilbertEprint/Working paper (2015) We consider two large neighborhood search approaches for the multitrip vehicle routing problem, where each vehicle can perform several routes during the working shift to serve a set of customers. The...
A branchandprice algorithm for 2period vehicle routing problemsCrama, Yves; Rezaei Sadrabadi, Mahmood; Van Woensel, TomEprint/Working paper (2015) We consider a Vehicle Routing Problem (VRP) with deterministic orders in two periods from a set of stores. Orders in period 1 (2) can be postponed (advanced) to the other period but any diversion from...
Machine Learning to Balance the Load in Parallel BranchandBoundMarcos Alvarez, Alejandro; Wehenkel, Louis; Louveaux, QuentinEprint/Working paper (2015) We describe in this paper a new approach to parallelize branchandbound on a certain number of processors. We propose to split the optimization of the original problem into the optimization of severa...
Short Prime Quadratizations of Cubic Negative MonomialsCrama, Yves; Rodriguez Heck, ElisabethEprint/Working paper (2014) PseudoBoolean functions naturally model problems in a number of different areas such as computer science, statistics, economics, operations research or computer vision, among others. PseudoBoolean o...
Conditional asset allocation: Does MarketWide Liquidity Matter?Bazgour, Tarik; Sougné, Danielle; Heuchenne, CédricEprint/Working paper (2012) This paper investigates the effect of marketwide liquidity on optimal portfolio allocations across US equity portfolios sorted by size and booktomarket characteristics. In particular, we consider a...
Optimally Locating Facilities with Variable CharacteristicsKucukaydin, HandeDoctoral thesis (2011) Facility location problems aim at optimally locating facilities like plants, warehouses, convenience stores, shopping malls etc. They can have different objectives such as maximizing the profit gained...
Critical analysis of the WORLDNET freight flow matricesChevalier, Simon; Limbourg, SabineEprint/Working paper (2010) The growing trade between Europe and the rest of the world and the enlargement of the European Union has led the European Commission’s DirectorateGeneral for Energy and Transport to fund Worldnet ...
RAPPORT DE RECHERCHE SUR UNE APPLICATION DE GESTION DE LA COLLABORATION DU SERVICE EXPÉDITION DU CHARGEUR AVEC LE TRANSPORTEURPironet, Thierry; Crama, Yves; Arda, Yasemin; Schyns, Michael; Rosso, Vanessa; Kronus, David; Wauthelet, Yves; Lange, JeanCharles; Tran, ViReport (2009) Dans ce rapport, les échanges d'information d'un donneur d'ordre, d'un transporteur et d'un fournisseur au sein d'une chaîne de distribution sont analysés. Les possibilités de tracking et de traci...
A Markov chain model of power indices in corporate structuresCrama, Yves; Leruth, Luc; Wang, SuEprint/Working paper (2009) This paper proposes to use a gametheoretic framework in analyzing complex corporate networks, notably in measuring the ``amount of control'' of both direct and indirect shareholders. The values of th...
Grafting Information in Scenario Trees: Application to Option PricesSchyns, Michael; Crama, Yves; Hübner, GeorgesEprint/Working paper (2005) The high level of sophistication in portfolio management modeling techniques often goes along with very large output sensitivity to parameter choices. As a potential solution to this problem, this pap...
The complexity of scheduling short tasks with few starting timesCrama, Yves; Spieksma, Frits C.R.Eprint/Working paper (1992) The following problem is proved to be NPcomplete: given n tasks, such that each task has processing time \tau=2, and has no more than k=3 possible starting times, does there exist a feasible schedule...
Papers  Books  Working Papers  Conferences
Conferences
Experimental investigation of decisionmaking processes in daily physically active behaviors using a virtual reality setupRuffault, Alexis; Cloes, Marc; Schyns, Michael; Bouchard, Stéphane; Fournier, Jean; Bossard, Cyril; Valembois, Quentin; Czernichow, Sébastien; Etienne, AnneMariePoster (2018, August) Background: Energy expenditure provided by physical activity (PA) can be significantly increased by daily behaviors (stair use, walking). However, factors from the environment, and motivational and vo...
Regularized discriminant analysis : a cellwise robust approachAerts, StéphanieScientific conference (2018, July 03) Quadratic and Linear Discriminant Analysis (QDA/LDA) are the most often applied classification rules under normality. In QDA, a separate covariance matrix is estimated for each group. If there are mor...
Assessing and predicting review helpfulnessHoffait, AnneSophie; Ittoo, AshwinConference (2018, July) Online customer reviews represent one of the most popular and accessible source of product/service information. Ecommerce platforms enable users to vote for review for their helpfulness, which act as...
Mapping IT Governance to Software Development Process: From COBIT 5 to GITroposNguyen, Vu H. A.; Kolp, Manuel; Wautelet, Yves; Heng, Samediin The 20th International Conference on Enterprise Information Systems (2018, July) Mapping IT Governance principles from frameworks like COBIT 5 to RequirementsDriven Software Processes such as (GI) Tropos or even RUPbased ones allows IT managers to propose governance and managem...
On Modelers Ability to Build a Visual Diagram from a User Story Set: A GoalOriented ApproachWautelet, Yves; Velghe, Mattijs; Heng, Samedi; Poelmans, Stephan; Kolp, Manuelin The 24th Working Conference on Requirements Engineering: Foundation for Software Quality (2018, March) [Context and Motivation] User Stories (US) are often used as requirement representation artifacts within agile projects. Within US sets, the nature, granularity and interdependencies of the elements ...
Indexing grey multilingual literature in General Practice in the era of Semantic WebJamoulle, Marc; Resnick, Melissa; Ittoo, Ashwin; Vander Stichele, Robert; Cardillo, Elena; Grosjean, Julien; Darmoni, Stefan; Vanmeerbeek, Marcin The Grey Journal (2017, October 23) Problem/Goal: Sharing the results of research with General Practitioners (GPs) is crucial for the survival of the discipline of General Practice / Family Medicine (GP/FM). The production of abstracts ...
Aligning Requirementsdriven Software Processes with IT GovernanceNguyen, Vu H. A.; Kolp, Manuel; Wautelet, Yves; Heng, SamediPoster (2017, July) Requirements Engineering is closely intertwined with Information Technology (IT) Governance. Aligning IT Governance principles with RequirementsDriven Software Processes allows then to propose govern...
Cellwise robust regularized discriminant analysisAerts, Stéphanie; Wilms, InesConference (2017, June 02) Quadratic and Linear Discriminant Analysis (QDA/LDA) are the most often applied classiﬁcation rules under normality. In QDA, a separate covariance matrix is estimated for each group. If there are mo...
Operational assessment of intermodality future in Belgium: Bestcase scenarioTawfik, Christine Maher Fouad; Limbourg, Sabinein Proceedings of the BIVEC/GIBET Transport Research Days 2017 (2017, May) From the perspective of stimulating intermodal transport as an ecological and economically promising freight transport scheme in the EU, this paper is devoted to assess its future position with respec...
Can any possible combination of modes improve intermodal attractiveness?Mostert, Martine; Caris, An; Limbourg, Sabinein Proceedings of the BIVECGIBET Transport Research Days 2017 (2017, May) In its White Paper on Transport, the European Commission recognizes intermodal transport as an alternative solution to road transport. In practice, intermodal transport can be constituted by any combi...
A terminology in General Practice / Family Medicine to represent nonclinical aspects for various usagesJamoulle, Marc; Grosjean, Julien; Ittoo, Ashwin; Resnick, Melissa; Treuherz, Arthur; Vander Stichele, Robert H; Cardillo, Elena; SHAMENEK, Frank; Vanmeerbeek, Marcin R. Randell et al. (Ed.) Informatics for Health: Connected CitizenLed Wellness and Population Health (2017, April 24) Abstract. The hereby proposed terminology called “QCodes” can be defined as an extension of the International Classification of Primary Care (ICPC2). It deals with nonclinical concepts that are...
Perspectives on User Story Based Visual TransformationsWautelet, Yves; Heng, Samedi; Kolp, ManuelPoster (2017, March) This paper summarizes previous works done by the authors on User Story (US) template unification and visual requirements models generation out of a US set. Indeed, transformation of a US set tagged us...
An Intentional Perspective on Partial Agile AdoptionKiv, Soreangsey; Heng, Samedi; Kolp, Manuel; Wautelet, Yvesin The 12th International Conference on Software Technologies (2017) Nowadays, the agile paradigm is one of the most important approaches used for software development besides structured and traditional life cycles. To facilitate its adoption and minimize the risks, di...
Towards a GoalOriented Framework for Partial Agile AdoptionKiv, Soreangsey; Heng, Samedi; Wautelet, Yves; Kolp, Manuelin Cabello, Enrique; Cardos, Jorge; Maciaszek, Leszek A.; van Sinderen, Marten (Eds.) Software Technologies (2017) The agile paradigm is used today for software development and project as an alternative to structured and traditional heavier life cycles. Different metamodels have been proposed trying to unify agil...
Bridging User Story Sets with the Use Case ModelWautelet, Yves; Heng, Samedi; Hintea, Diana; Kolp, Manuel; Poelmans, Stephanin Advances in Conceptual Modeling (2016, November) User Stories (US) are mostly used as basis for representing requirements in agile development. Written in a direct manner, US fail in producing a visual representation of the main systemtobe functio...
A Bilevel Design and Pricing Model for an Intermodal Service NetworkTawfik, Christine Maher Fouad; Limbourg, SabineScientific conference (2016, September 09) This work addresses the problem of jointly designing and pricing intermodal freight services during a mediumterm planning horizon. Given the innate hierarchy in the problem, a bilevel program is cons...
Optimal returnable transport items managementLimbourg, Sabine; Martin, Adeline; Paquay, CéliaConference (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 ...
BRAINTRAINS: Scenario development to explore intermodal rail transport expansion in, from and towards BelgiumTroch, Frank; Vanelslander, Thierry; Sys, Christa; Stevens, Vidar; Verhoest, Koen; Tawfik, Christine Maher Fouad; Mostert, Martine; Limbourg, Sabine; Merchan Arribas, Angel; Belboom, SandraConference (2016, July)
Monitoring partnership networks A graph theory approachFaraz, Alireza; Treiblmaier, Horst; Gerschberger, MarkusConference (2016, June 17) Recently, companies are forming strong relationships with their strategic suppliers and customers in order to maximize their profit in the global market. Such a partnership or strategic alliance is ba...
Building a rationale diagram for evaluating user story setsWautelet, Yves; Heng, Samedi; Kolp, Manuel; Mirbel, Isabelle; Poelmans, Stephanin 2016 IEEE Tenth International Conference on Research Challenges in Information Science (RCIS) (2016, June) Requirements representation in agile methods is often done on the basis of User Stories (US) which are short sentences relating a WHO, WHAT and (possibly) WHY dimension. They are by nature very operat...
Direct control service from residential heat pump aggregation with specified paybackGeorges, Emeline; Cornélusse, Bertrand; Ernst, Damien; Louveaux, Quentin; Lemort, Vincent; Mathieu, Sébastienin Proceedings of the 19th Power Systems Computation Conference (PSCC) (2016, June) This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or do...
La distribution par des véhicules électriquesBay, Maud; Limbourg, SabineScientific conference (2016, May 25) The objective of vehicle routing problems is to design a set of efficient vehicle routes to provide goods from a depot to a set of customers satisfying specific constraints. Classical variants of thes...
Accounting for price endogeneity in airline itinerary choice modelsLurkin, Virginie; Garrow, Laurie; Higgins, Matthew; Newman, Jeffrey; Schyns, MichaelConference (2016, May 20) This study formulates an itinerary choice model that is consistent with those used by industry and corrects for price endogeneity using a control function that uses several types of instrumental varia...
Towards an Agentdriven Software Architecture Aligned with User StoriesWautelet, Yves; Heng, Samedi; Kolp, Manuel; Scharff, Christellein 8th International Conference on Agents and Artificial Intelligence (2016, February) Agile principles have taken an increasing importance in the last decades. Software Architecture (SA) definition is perceived as a nonagile practice as it is executed in a topdown manner, reminding w...
Multivariate coefficients of variation: a full inference toolboxAerts, Stéphanie; Haesbroeck, GentianeConference (2015, December 13) The univariate coefficient of variation (CV) is a widely used measure to compare the relative dispersion of a variable in several populations. When the comparison is based on $p$ characteristics howev...
Modeling the dependence between extreme operational losses and economic factors: a conditional semiparametric Generalized Pareto approachHambuckers, julien; Heuchenne, Cédric; Lopez, OlivierConference (2015, December) In this paper, we model the severity distribution of operational losses data, condi tional on some covariates. Indeed, previous studies [Chernobai et al., 2011, Cope et al., 2012, ChavezDemoulin et ...
Monitoring The quality Loss Performance of ProductsFaraz, Alireza; Treiblmaier, HorstConference (2015, November 03) This paper presents a control chart based on the Taguchi (1986)’s loss function for monitoring the performance of a process and its capability in monetary form. The proposed chart monitors the loss ...
Quadratizations of pseudoBoolean functionsCrama, YvesConference (2015, October 23) A pseudoBoolean function is a realvalued function of 01 variables. Every pseudoBoolean function can be represented by various analytical expressions, e.g., as a polynomial in its variables, or as ...
Brain trains: scenario development to explore intermodal rail transport expansion in, from and towards BelgiumTroch, Frank; Vanelslander, Thierry; Belboom, Sandra; Léonard, Angélique; Limbourg, Sabine; Merchan Arribas, Angel; Mostert, Martine; Tawfik, Christine Maher Fouad; Stevens, Vidar; Sys, Christa; Verhoest, KoenConference (2015, September)
Estimation of Airline Itinerary Choice Models Using Disaggregate Ticket DataLurkin, Virginie; Garrow, Laurie A.; Higgins, Matthew J.; Schyns, Michaelin 55th AGIFORS Annual Proceedings 2015 (2015, August 29) Airline itinerary choice models support many multimillion dollar decisions, i.e., they are used to evaluate potential route schedules. Classic models suffer from major limitations, most notably they ...
Brain Trains: Intermodal Rail Freight Transport and Hinterland Connections  A Swot Analysis to Assess the Belgian Rail PracticeTroch, Frank; Vanelslander, Thierry; Sys, Christa; Belboom, Sandra; Léonard, Angélique; Limbourg, Sabine; Merchan Arribas, Angel; Mostert, Martine; Stevens, Vidar; Tawfik, Christine Maher Fouad; Verhoest, Koenin Proceedings of the IAME Annual Conference 2015 (2015, August) This paper focuses on transversal research of the role and influences of rail freight transport, as a part of intermodal transport in Belgium. The scope of the research concentrates on port hinterland...
A general lotsizing problem with uncertain product returnsAmand, Guillaume; Arda, YaseminConference (2015, July 15) We consider a singlestage system that produces a range of final products. The demands of the final products are supposed deterministic over a finite planning horizon. Each unit of demand has to be fu...
Feasibilityoriented Branching Strategies for Global OptimizationGerard, Damien; Köppe, Matthias; Louveaux, QuentinConference (2015, July 13) We study the spatial BrandandBound algorithm for the global optimization of nonlinear problems. In particular we are interested in a method to find quickly good feasible solutions. Most spatial Bran...
Shewhart Control Charts with Guaranteed InControl PerformanceFaraz, Alireza; Heuchenne, Cédric; Woodall, W.H.Conference (2015, July 08) The incontrol performance of the Shewhart X ̅ and S2 control charts with estimated incontrol parameters has been evaluated by a number of authors. Results indicate an unrealistically large amount o...
Bilevel optimization in the context of intermodal pricing: state of artTawfik, Christine Maher Fouad; Limbourg, Sabinein Proceedings of the 18th Euro Working Group on Transportation, EWGT 2015 (2015, July) With the rising interest to stimulate intermodal transport, determining pricing strategies can be intrinsically challenging. We provide a review on the current state of research in intermodal pricing,...
What the heck is Revenue ManagementLurkin, Virginie; Schyns, Michael; Garrow, LaurieScientific conference (2015, May 08) The airline industry changed dramatically in 1978 when it became deregulated. Operations research analysts played a critical role after deregulation by developing algorithms and decisionsupport syste...
BRAIN TRAINS: Intermodal rail freight transport and hinterland connections A SWOT analysis to assess the Belgian rail practiceTroch, Frank; Vanelslander, Thierry; Belboom, Sandra; Léonard, Angélique; Limbourg, Sabine; Merchan Arribas, Angel; Mostert, Martine; Pauwels, Tom; Vidar, Stevens; Sys, Christa; Tawfik, Christine Maher Fouad; Verhoest, KoenScientific conference (2015, May) This paper focuses on transversal research of the role and influences of rail freight transport, as a part of intermodal transport in Belgium. A SWOT analysis of the current situation is conducted, st...
Early detection of university students in potential difficultyHoffait, AnneSophie; Schyns, MichaelConference (2015, February) Rate of success in the first year at University in Belgium is very low regarding other foreign universities. The University of Liege, as other Universities, has already taken different initiatives. Bu...
Optimal Assignment of OffPeak Hours to Lower Curtailments in the Distribution NetworkMerciadri, Luca; Mathieu, Sébastien; Ernst, Damien; Louveaux, Quentinin Proceedings of the 5th European Innovative Smart Grid Technologies (ISGT) (2015) We consider a price signal with two settings: offpeak tariff and onpeak tariff. Some loads are connected to specific electricity meters which allow the consumption of power only in offpeak periods....
The Airline Container Loading Problem with Pickup and DeliveryLurkin, Virginie; Schyns, MichaelConference (2014, November 09) We address the problem of allocating containers into predefined positions of a carrier, in this case aircraft, under several realistic structural and safety constraints. The originality of our approac...
The Airline Container Loading Problem with Pickup and DeliveryLurkin, Virginie; Schyns, Michaelin Airline Group of the Intl Federation of Operational Research Soc ( AGIFORS ) (Ed.) 54th AGIFORS Annual Proceedings 2014 (2014, October 19) 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...
Robustness and efficiency of multivariate coefficients of variationAerts, Stéphanie; Haesbroeck, Gentiane; Ruwet, ChristelConference (2014, August 12) The coefficient of variation is a wellknown measure used in many fields to compare the variability of a variable in several populations. However, when the dimension is greater than one, comparing the...
Relaxations for multiperiod optimal power flow problems with discrete decision variablesGemine, Quentin; Ernst, Damien; Louveaux, Quentin; Cornélusse, Bertrandin Proceedings of the 18th Power Systems Computation Conference (PSCC'14) (2014, August) We consider a class of optimal power flow (OPF) applications where some loads offer a modulation service in exchange for an activation fee. These applications can be modeled as multiperiod formulatio...
A quantitative analysis of the effect of flexible loads on reserve marketsMathieu, Sébastien; Louveaux, Quentin; Ernst, Damien; Cornélusse, Bertrandin Proceedings of the 18th Power Systems Computation Conference (PSCC) (2014, August) We propose and analyze a dayahead reserve market model that handles bids from flexible loads. This pool market model takes into account the fact that a load modulation in one direction must usually b...
Specific Multitrip Operators for Vehicle Routing ProblemsArda, Yasemin; Crama, Yves; François, Véronique; Laporte, GilbertConference (2014, July 17) In vehicle routing problems with multiple trips (VRPM), each vehicle is allowed to perform more than one trip during its working period. Classical solution techniques for this problem use existing VRP...
Logistics hub: the case of LiègeLimbourg, Sabine; Mostert, Martine; Paquay, CéliaConference (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 develope...
Early detection of university students in potential difficultyHoffait, AnneSophie; Schyns, MichaelConference (2014, January) Rate of success in the first year at University in Belgium is very low regarding other foreign universities. The University of Liege, as other Universities, has already taken different initiatives. Bu...
Lipschitz robust control from offpolicy trajectoriesFonteneau, Raphaël; Ernst, Damien; Boigelot, Bernard; Louveaux, Quentinin Proceedings of the 53rd IEEE Conference on Decision and Control (IEEE CDC 2014) (2014) We study the minmax optimization problem introduced in [Fonteneau et al. (2011), ``Towards min max reinforcement learning'', Springer CCIS, vol. 129, pp. 6177] for computing control policies for batc...
Unifying and Extending User Story ModelsWautelet, Yves; Heng, Samedi; Kolp, Manuel; Mirbel, Isabellein Matthias, Jarke; Mylopoulos, John; Quix, Christoph; Rolland, Colette; Manolopoulos, Yannis; Mouratidis, Haralambos; Horkoff, Jennifer (Eds.) Advanced Information Systems Engineering (2014) Within Agile methods, User Stories (US ) are mostly used as primary requirements artifacts and units of functionality of the project. The idea is to express requirements on a low abstraction basis usi...
A new methodological approach for error distributions selectionHambuckers, julien; Heuchenne, CédricConference (2013, December 15) 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 ValueatRisk (VaR) predictions. We ...
A new methodological approach for error distributions selectionHambuckers, julien; Heuchenne, CédricScientific conference (2013, November) 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 ValueatRisk (VaR) predictions. We ...
Empty Container Management in the Benelux WaterwaysSalmon, Frédéric; Limbourg, Sabinein Pianic Smart Rivers 213 (2013, September 25) The scientific contribution of this paper is the development of a model for empty container management in the hinterlands of the ports of Antwerp and Rotterdam. The objective of the proposed model is ...
Characteristics of Economically Designed CUSUM and \bar{X} Control ChartsSaniga, Erwin; Davis, Darwin; Faraz, Alireza; McWilliams, Thomas; Lucas, JamesConference (2013, August 22) In this paper we investigate the characteristics of economic control chart designs for both Shewhart (¯X ) and CUSUM control charts. Authors in the past have made some suggestions regarding the desig...
The Airline Container Loading Problem with Pickup & Delivery and Multi DoorsSchyns, Michael; Lurkin, Virginiein 53rd AGIFORS Annual Proceedings 2013: Annual Symposium and Study Group Meeting (2013, August) We address the problem of allocating containers into predefined positions of a carrier, in this case aircraft, under several realistic structural and safety constraints, including the management of se...
The Airline Container Loading Problem with Pickup and DeliveryLurkin, Virginie; Schyns, MichaelConference (2013, July 02) We address the problem of allocating containers into predefined positions of a carrier, in this case aircraft, under several realistic structural and safety constraints. The originality of our approac...
A global optimization method for naval structure op timizationBay, Maud; Crama, Yves; Rigo, PhilippeConference (2013, July 01) The paper proposes a global optimization method for the preliminary structural design of large vessels in shipbuilding industry. We face a combinatorial problem of large size, with constraints modeled...
The economic and environmental feasibility of biogas buses in LiegeMostert, Martine; Limbourg, Sabinein 2013 BIVECGIBET Transport Research Days  Proceedings (2013, May 30) Everyday, many students at the University of Liège have to drive to the SartTilman village to attend their courses. These journeys are responsible for the emission of harmful particles which have ne...
Monitoring distribution networks in supply chainsFaraz, AlirezaConference (2013, May 17) This paper presents a new control chart for monitoring the post optimality of a designed distribution network in a supply chain. The proposed control chart alarms as soon as neither the location nor t...
An elementary shortest path problem with variable service start timeKucukaydin, Hande; Arda, Yasemin; Crama, YvesConference (2013, May 02) We consider an elementary shortest path problem with resource constraints (ESPPRC), where a capacitated single vehicle serves a set of delivery and backhaul customers with a revenue and a time window....
Quadratization of symmetric pseudoBoolean functionsCrama, YvesConference (2013, April) We consider the problem of minimizing an arbitrary pseudoBoolean function f(x), that is, a realvalued function of 01 variables. In recent years, several authors have proposed to reduce this problem...
Automatic Aircraft Cargo Load Planning with Pickup and DeliveryLurkin, Virginie; Schyns, MichaelConference (2013, March 15) This research aims to develop a new mixed integer linear program to solve the containers assignment problem when pickup and deliveries are considered. Given a pool of ULDs and an aircraft with multipl...
Elective Course Allocation with numerical preferencesBay, Maud; Homburg, DavidConference (2013, February 14) In Universities, students have to select a specified number of elective courses to be included in their curriculum. Elective courses are a good way to increase students motivation and improve their ac...
Optimization model for empty container repositioningSalmon, Frédéric; Limbourg, SabineScientific 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 ...
Automatic Aircraft Cargo Load Planning with Pickup and DeliveryLurkin, Virginie; Schyns, MichaelConference (2013, February 07) This research aims to develop a new mixed integer linear program to solve the containers assignment problem when pickup and deliveries are considered. Given a pool of ULDs and an aircraft with multipl...
Optimization model for empty container repositioningSalmon, Frédéric; Limbourg, SabineConference (2013, February 07) Empty container management is a transportation issue relating to the imbalance of container demand and supply in various parts of the world. Hence the necessity for shippers to move empty containers t...
Méthodes Booléennes en recherche opérationnelleCrama, YvesConference (2013, February) Le titre de cette conférence est celui d'une monographie cosignée par Peter L. Hammer et Sergiu Rudeanu, et dont la publication en 1968 a inspiré un nombre important de travaux de recherche. Très ...
Algorithms for testing the collective consumption modelTalla Nobibon, Fabrice; Cherchye, Laurens; Crama, Yves; Demuynck, Thomas; De Rock, Bram; Spieksma, FritsConference (2012, November 09) In this talk, we discuss an extension of the strong axiom of revealed preferences to collective households. The question that we address is whether a set of observed consumption baskets can be decompo...
Inland intermodal freight transport modellingCarreira, Joana; Santos, Bruno; Limbourg, Sabinein ETC Proceedings (2012, October 10) The demand for goods has grown in the past decades, in such a way that today freight transport has become essential for the support of modern economies. The search for a competitive freight transport ...
Automatic Cargo Load Planning: Special shipmentsKleyntssens, Thomas; Limbourg, Sabine; Schyns, Michaelin ILS 2012 Proceedings (2012, August 28) The aircraft loading problem is a realworld combinatorial optimisation problem highly constrained. Indeed, loading the aircraft so the gross weight is less than the maximum allowable is not enough. T...
Three dimensional Bin Packing Problem applied to air cargoPaquay, Célia; Schyns, Michael; Limbourg, Sabinein ILS 2012 Proceedings (2012, August 26) Deciding whether a set of three dimensional boxes can be packed into a container is a NPhard problem. Mathematical models have been developed, however, only few studies take into account constraints ...
A UsageBased Unified Resource ModelWautelet, Yves; Heng, Samedi; Kolp, Manuelin The 24th International Conference on Software Engineering and Knowledge Engineering (2012, July) Most of the time engineering methodologies focus on the modeling of functional and nonfunctional requirements of the systemtobe with no or poor representation of resource elements. Resources are ne...
Boolean Methods and Logical Analysis of DataCrama, YvesConference (2012, June 09) About 20 years ago, we proposed an innovative approach to data mining based on a blend of Boolean techniques and combinatorial optimization. The basic tenets of this approach were presented in a joint...
Multiperiod vehicle loading with stochastic release datesArda, Yasemin; Crama, Yves; Kronus, David; Pironet, Thierry; Van Hentenryck, PascalConference (2012, May 24) Production scheduling and vehicle routing problems are wellknown topics in operations management. Although these tasks are consecutive in the supply chain, few optimization models tackle the associat...
Optimisation 3D du chargement de conteneurs pour le transport aérienPaquay, Célia; Limbourg, Sabine; Schyns, Michaelin 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 pr...
Three dimensional Bin Packing Problem applied to air transportPaquay, Célia; Schyns, Michael; Limbourg, SabineConference (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 t...
A Rich Vehicle Routing Problem with Multiple Trips and Driver ShiftsArda, Yasemin; Crama, Yves; Kucukaydin, Hande; Talla Nobibon, FabriceConference (2012) This study is concerned with a rich vehicle routing problem (RVRP) encountered at a Belgian transportation company in charge of servicing supermarkets and hypermarkets belonging to a franchise. The st...
An ontological basis for resource representationWautelet, Yves; Heng, Samedi; Kolp, ManuelPoster (2012) This paper proposes an ontology for resource representation driven by the concepts of functionality and competency depending on their type. These concepts are used to centralize resources’ offer and...
Three Dimensional Bin Packing Problem applied to air cargoPaquay, Célia; Schyns, Michael; Limbourg, SabineScientific conference (2011, December 15) Deciding whether a set of three dimensional boxes can be packed into a container is a NPhard problem. Mathematical models have been developed, however, only few studies take into account constraints ...
Boolean methods in operations research and related areasCrama, YvesConference (2011, November) These are the slides of the "IFORS Distinguished Lecture" that I delivered at the INFORMS Annual meeting in November 2011. The title of the lecture is the title of a monograph coauthored by...
A capacity game in transportation managementAmand, Guillaume; Arda, YaseminConference (2011, July 10) This study analyzes the contractual relation between a retailer and a carrier with the aim of determining possible deviations from the optimal system performance. In order to face a random demand, the...
Automatic Cargo Load Planning: Special shipmentsLimbourg, Sabine; Schyns, MichaelScientific conference (2011, May 25) The aircraft loading problem is a realworld combinatorial optimisation problem highly constrained. Indeed, loading the aircraft so the gross weight is less than the maximum allowable is not enough. T...
A capacity game in transportation managementAmand, Guillaume; Arda, YaseminConference (2011, March 03) Emerging concerns about competitiveness induce a growing number of firms to outsource their outbound transportation operations to thirdparty logistics providers. The resulting increase in the number ...
Automatic Cargo Load PlanningLimbourg, Sabine; Schyns, Michael; Laporte, Gilbertin Proceedings (2011, March 02) The goal of this paper is the development of a new mixed integer linear pro gram designed for optimally loading a set of containers and pallets into a compartmentalised cargo aircraft. It is based on...
Online Sparse Bandit for Card GamesLupien StPierre, David; Louveaux, Quentin; Teytaud, Olivierin Advance in Computer Games (2011) Finding an approximation of a Nash equilibria in matrix games is an important topic that reaches beyond the strict application to matrix games. A bandit algorithm commonly used to approximate a Nash e...
AUTOMATIC CARGO LOAD PLANNINGLimbourg, SabineConference (2010, December 14) The aircraft loading problem is a realworld combinatorial optimisation problem highly constrained. Indeed, loading the aircraft so the gross weight is less than the maximum allowable is not enough. T...
Location and market area of railroad terminalsLimbourg, Sabine; Jourquin, BartScientific conference (2010, January 28) The European transport policy has focused on sustainable transport solutions. One of its objectives for freight transport is to restore the balance between modes and to develop intermodality. Among th...
A capacity game in transportation planningAmand, Guillaume; Arda, YaseminConference (2010, January 28) Emerging concerns about competitiveness induce a growing number of firms to outsource their outbound transportation operations to thirdparty logistics providers. The resulting increase in the number ...
A hybrid tabu search heuristic for a bilevel competitive facility location modelKucukaydin, Hande; Aras, Necati; Altinel, I. Kubanin Blesa, Maria J.; Blum, Christian; Raidl, Günther; Roli, Andrea; Sampels, Michael (Eds.) Hybrid metaheuristics: 7th International Workshop, HM 2010, Vienna, Austria, October 2010, Proceedings (2010) We consider a problem in which a firm or franchise enters a market by locating new facilities where there are existing facilities belonging to a competitor. The firm aims at finding the location and a...
Split rank of tworow cutsLouveaux, QuentinConference (2009, December) A simple relaxation consisting of two rows of a simplex tableau is a mixedinteger set with two equations, two free integer variables, and nonnegative continuous variables. Recently, Andersen et al. a...
Vehicle loading optimization with stochastic supplyAmand, Guillaume; Arda, Yasemin; Crama, Yves; Kronus, David; Pironet, ThierryConference (2009, July 07) The increased availability of information makes it possible to coordinate processes which are usually functionnally separated in large companies, such as production and transportation. This work inves...
Using OR techniques for projets selection in the petrol industyBELAID, Fateh; de Wolf, DanielConference (2009, February 05) Two important characteristics of petroleum exploration and production investment are the high nancial amounts and uncertainties. For these rea sons, the risk analysis should be implemented in the pro...
Split rank of triange and quadrilateral inequalitiesLouveaux, QuentinConference (2009, January) A simple relaxation consisting of two rows of a simplex tableau is a mixedinteger set with two equations, two free integer variables, and nonnegative continuous variables. Recently, Andersen et al. a...
Robust Portfolio SelectionSchyns, Michaelin JSM Proceedings, Statistical Computing Section (2008, November) In many financial problems, small variations in some inputs may result in big changes in the outputs. In this talk, we consider the problem of portfolio selection as suggested by Markowitz. This model...
A profitable pickup and delivery problem with time windowsArda, Yasemin; Crama, Yves; Pironet, ThierryConference (2008, January 18) In most pickup and delivery problems, usually the aim is to minimize either the trip length or duration or the fleet size. Transportation orders or customers are finite sets which should be performed ...
Multicriterion Scantling Optimization of the Midship Section of a Passenger Vessel considering IACS RequirementsRichir, Thomas; Caprace, JeanDavid; Losseau, Nicolas; Bay, Maud; Parsons, Michael G.; Patay, Samuel; Rigo, Philippein The 10th International Symposium on Practical Design of Ships and Other Floating Structures (PRADS) (2007, October) In the scantling design of a passenger ship, minimum production cost, minimum weight and maximum moment of inertia (stiffness) are conflicting objectives. For that purpose, recent improvements were ma...
A mixedinteger heuristic for the structural optimization of a cruise shipBay, Maud; Crama, Yves; Richir, Thomas; Rigo, Philippein COMPIT 2007 , Cortona, Italy (2007, April 23) A heuristic approach is proposed to solve the structural optimization problem of a cruise ship. The challenge of optimization is to define the scantling of the structure of a ship in order to minimize...
Cutting planes from latticepointfree polyhedraLouveaux, QuentinConference (2007, January) In this talk, we generalize the concept of a split (that leads to split cuts) to any latticepointfree polyhedron. We show how we can generate cutting planes for a polyhedron from these objects. Asso...
Inventory control in a decentralized twostage maketostock queuing systemArda, Yasemin; HENNET, JeanClaudein INCOM 06, 12th IFAC Symposium on Information Control Problems in Manufacturing, SaintEtienne, France, 1719 May 2006 (2006, May 17) In an Enterprise network, several companies interact to produce families of goods. Each member company seeks to optimize his own production and inventory policy to maximize his profit. These objective...
Contracting in manufacturing networks with inventoriesArda, Yasemin; Hennet, JeanClaudeConference (2006, April 18) An important issue in the management of supply chains and manufacturing systems is to achieve the desired customer service level while respecting the individual economic objectives of the partners. Th...
Coordination de chaînes logistiques, une approache par la théorie des jeuxArda, Yasemin; Hennet, JeanClaudein MOSIM 06, 6e Conférence Francophone de MOdélisation et SIMulation, Rabat, Maroc, 35 Avril 2006 (2006, April 03) Les chaînes logistiques étudiées sont constituées de différentes entreprises qui interviennent dans le processus de fabrication d’une famille de produits. Pour chaque entreprise, il s’agit pr...
Supply chain coordination through contract negotiationArda, Yasemin; Hennet, JeanClaudein DCECC 06, 44th IEEE Conference on Decision and Control and the European Control Conference, Seville, Spain, 1215 December 2005 (2005, December 12) The purpose of the paper is to evaluate the efficiency of different types of contracts between the industrial partners of a supply chain. Such an evaluation is made on the basis of the relationship be...
Discrete optimizationLouveaux, QuentinPoster (2005, September) Have you ever wondered what is the shortest route to join the office? What is the best way to plan a trip through several cities? You have maybe already played with magical squares? Then you have met ...
Optimization of Surface Allocation using Heuristic ApproachesLanger, Yves; Bay, Maud; Crama, Yves; Bair, Frédéric; Caprace, JeanDavid; Rigo, Philippein COMPIT 2005 , Hambourg, Germany (2005, May) In this paper, we present a scheduling problem that arises in factories producing large building blocks (in our case, a shipyard workshop producing prefabricated keel elements). The factory is divided...
Valid inequalities for the intersection of two knapsacksLouveaux, QuentinConference (2005, March) We address the question to what extent polyhedral knowledge about individual knapsack constraints suffices or lacks to describe the convex hull of the binary solutions to their intersection. It turns ...
Optimal location of intermodal terminalsJourquin, Bart; Limbourg, SabineConference (2005) The optimal location of a facility is a rather complex task that was already studied many times. Several optimal location problems and solution exists, but only a few can be applied to the location of...
InterModal Terminals for FreightLimbourg, Sabine; Jourquin, BartConference (2005) The optimal location of terminals and logistic centres is an uptodate research topic. The first goal of this paper is to outline a method that helps to isolate the best potential locations. The basi...
Solving the mTSP Problem with Stochastic or Time Dependent DemandsLouveaux, François; Schyns, Michaelin Opasanon, S.; MillerHooks, E. (Eds.) Proceedings of TRISTAN V (Triennial Symposium on Transportation Analysis) (2004, June) There are many examples of problems in transportation where some elements are uncertain. In the distribution of goods as well as systems responding to calls for emergency, demands typically occur in a...
Optimizing the ordering policy in a supply chainArda, Yasemin; Hennet, JeanClaudein INCOM 04, 11th IFAC Symposium on Information Control Problems in Manufacturing, Salvador, Brazil, 57 April 2004 (2004, May 05) This study analyzes an inventory management problem within a supply chain. An enterprise whose stock is replenished by outside suppliers faces random demands for one of its products. The objective is ...
Inventory control in a multisupplier systemArda, Yasemin; Hennet, JeanClaudein IGLS 04, 13th International Working Seminar on Production Economics, Igls/Innsbruck, Austria, 1620 February 2004 (2004, February 16) An enterprise network is analyzed from the viewpoint of an endproduct manufacturer who receives customer orders and organises his production and supply policy so as to minimize the sum of his average...
Optimal location of intermodal terminalsJourquin, Bart; Limbourg, SabineConference (2004) The known methods to solve the problem of the optimal location of intermodal terminals are “node” based, in the sense that they use the locations of the demands and the supplies as main input. Th...
An introduction to the ELECTRE research programmeCrama, Yves; Hansen, Pierrein Hansen, Pierre (Ed.) Essays and Surveys on Multiple Criteria Decision Making (1983) The discrete multicriteria decision problem has attracted a large amount of attention during the last 15 years. In contrast with multiattribute utility theory, prevailing in the U.S., a series of met...

