Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise

Montréal, Canada

Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise

Montréal, Canada

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PubMed | Vienna University of Economics and Business and Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise
Type: Journal Article | Journal: Computers & operations research | Year: 2014

In this paper, we introduce two algorithms to address the two-echelon capacitated location-routing problem (2E-CLRP). We introduce a branch-and-cut algorithm based on the solution of a new two-index vehicle-flow formulation, which is strengthened with several families of valid inequalities. We also propose an adaptive large-neighbourhood search (ALNS) meta-heuristic with the objective of finding good-quality solutions quickly. The computational results on a large set of instances from the literature show that the ALNS outperforms existing heuristics. Furthermore, the branch-and-cut method provides tight lower bounds and is able to solve small- and medium-size instances to optimality within reasonable computing times.


Abbasgholizadeh Rahimi S.,Laval University | Abbasgholizadeh Rahimi S.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Abbasgholizadeh Rahimi S.,Center Interdisciplinaire Of Recherche En Readaptation Et Integration Sociale Cirris | Jamshidi A.,Laval University | And 8 more authors.
Decision Support Systems | Year: 2016

This study reviews current patients' prioritization systems and presents an innovative integrated three-step decisional framework in an attempt to overcome their limitations. In its first step, the proposed framework encompasses fuzzy logic, analytic hierarchy process (AHP) to formalize stakeholders' goals and objectives. In the second step, the assessments made on each patient's condition are integrated by data envelopment analysis (DEA) and compared among them by a min–max regret approach (MRA) to obtain a primary prioritization of patients. The third step uses the delay ratio, the risk criteria score, and a profile matrix to introduce dynamic aspects related to the evolution of patients' condition and changes in the patient's list to the prioritization process. This three-step framework not only considers the surgery team members' opinions but also considers the patient's opinions in the decision-making process. The new framework has been implemented in the Orthopedic Surgery Ward, Shohada University Hospital, Iran, showing very promising results and advantages. © 2016 Elsevier B.V.


Gaudreault J.,Laval University | Gaudreault J.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Frayret J.-M.,Laval University | Frayret J.-M.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | And 3 more authors.
Computers and Operations Research | Year: 2011

Many research initiatives carried out in production management consider process planning and operations scheduling as two separate and sequential functions. However, in certain contexts, the two functions must be better integrated. This is the case in divergent production systems with co-production (i.e. production of different products at the same time from a single product input) when alternative production processes are available. This paper studies such a context and focuses on the case of drying and finishing operations in a softwood lumber facility. The situation is addressed using a single model that simultaneously performs process planning and scheduling. We evaluate two alternative formulations. The first one is based on mixed integer programming (MIP) and the second on constraint programming (CP). We also propose a search procedure to improve the performance of the CP approach. Both approaches are compared with respect to their capacity to generate good solutions in short computation time. © 2010 Elsevier Ltd. All rights reserved.


Anaya-Arenas A.M.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Anaya-Arenas A.M.,Laval University | Chabot T.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Chabot T.,Laval University | And 4 more authors.
International Journal of Production Research | Year: 2015

Biomedical sample management plays a central role in an efficient health care system and requires important resources. Based on our collaboration with the Quebec’s Ministère de la Santé et des Services sociaux (Ministry of Health and Social Services), this article describes the challenging context of biomedical sample transportation in the Canadian province of Quebec. It is modelled on a variant of the multi-trip vehicle routing problem with time windows where routes need to be planned from a laboratory to satisfy the multiple pick-up requests of each sample collection centre under some practical constraints. We propose and evaluate two alternative mathematical formulations, as well as fast heuristics, to minimise total transportation distances. The performance of the proposed methods is assessed over a large case study based on the network of laboratories in the province of Quebec. © 2015 Taylor & Francis


Deflorio F.P.,Polytechnic University of Turin | Perboli G.,Polytechnic University of Turin | Perboli G.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Tadei R.,Polytechnic University of Turin
Flexible Services and Manufacturing Journal | Year: 2010

This paper studies the use of performance indicators in routing problems to estimate how transportation cost is affected by the quality of service offered. The quality of service is assumed to be directly dependent on the size of the time windows. Smaller time windows mean better service. Three performance indicators are introduced. These indicators are calculated directly from the data without the need of a solution method. The introduced indicators are based mainly on a "request compatibility", which describes whether two visits can be scheduled consecutively in a route. Other two indicators are introduced, which get their values from a greedy constructive heuristic. After introducing the indicators, the correlation between indicators and transportation cost is examined. It is concluded that the indicators give a good first estimation on the transportation cost incurred when providing a certain quality of service. These indicators can be calculated easily in one of the first planning steps without the need of a sophisticated solution tool. The contribution of the paper is the introduction of a simple set of performance indicators that can be used to estimate the transportation cost of a routing problem with time windows. © 2011 Springer Science+Business Media, LLC.


Cote J.-F.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Gendreau M.,Ecole Polytechnique de Montréal | Gendreau M.,University of Montréal | Potvin J.-Y.,University of Montréal
Operations Research | Year: 2014

This paper describes an exact algorithm for solving a two-dimensional orthogonal packing problem with unloading constraints, which occurs as a subproblem of mixed vehicle routing and loading problems. The packing considered in this work is basically a feasibility problem involving a single bin. The problem is addressed through a decomposition approach wherein a branch-and-cut algorithm is designed for solving a one-dimensional relaxation of the original problem. When an integer solution is found in the branching tree, a subsidiary problem is solved to identify a two-dimensional packing that does not lead to any overlap and satisfies the unloading constraints. Cuts are added when the subsidiary problem proves to be infeasible. Several preprocessing techniques aimed at reducing the size of the solution space and uncovering infeasibility are also described. A numerical comparison with the best known exact method is reported at the end based on benchmark instances. © 2014 INFORMS.


Mohammadian S.H.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Mohammadian S.H.,Institute Of Readaptation En Deficience Physique Of Quebec | Ait-Kadi D.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Ait-Kadi D.,Institute Of Readaptation En Deficience Physique Of Quebec | Routhier F.,Institute Of Readaptation En Deficience Physique Of Quebec
Reliability Engineering and System Safety | Year: 2010

The concept of accelerated testing by tracking degradation of samples over test time needs to be developed for reliability estimation. This paper aims at proposing practical approaches to conduct accelerated degradation testing on new and available used samples. For this purpose, product failure is related to a suitable physical property. Then, its failure time is defined as the expected time in which its property reaches the critical level. Degradation model of field samples returned from service due to a degrading failure mode has been estimated based on the least square method, and available gap between manufacturer criterion and user's claim (to report a failure) has also been discussed. For a product under some stresses, a general formula has been proposed by the superposition principle in order to estimate its degradation for independent and dependent failure modes. If used samples are available, and acceleration factor of the related test is unknown, partial aging method has been presented to considerably shorten the test time. © 2009 Elsevier Ltd. All rights reserved.


Jena S.D.,University of Montréal | Jena S.D.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Cordeau J.-F.,HEC Montréal | Cordeau J.-F.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | And 2 more authors.
Computers and Operations Research | Year: 2016

Motivated by an industrial application, we consider a recently introduced multi-period facility location problem with multiple commodities and multiple capacity levels. The problem allows for the relocation of facilities, as well as for the temporary closing of parts of the facilities, while other parts remain open. In addition, it uses particular capacity constraints that involve integer rounding of the allocated demands. In this paper, we propose a strong formulation for the problem, as well as a hybrid heuristic that first applies Lagrangian relaxation and then constructs a restricted mixed-integer programming model based on the previously obtained Lagrangian solutions. Computational results for large-scale instances emphasize the usefulness of the heuristic in practice. While general-purpose mixed-integer programming solvers do not find feasible solutions for about half of the instances, the heuristic consistently provides high-quality solutions in short computing times, as well as tight bounds on their optimality. © 2015 Elsevier Ltd.All rights reserved.


Mohammadian S.H.,Institute Of Readaptation En Deficience Physique Of Quebec | Mohammadian S.H.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Routhier F.,Institute Of Readaptation En Deficience Physique Of Quebec | Ait-Kadi D.,Institute Of Readaptation En Deficience Physique Of Quebec | Ait-Kadi D.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise
International Journal of Performability Engineering | Year: 2011

This paper presents two approaches for selecting qualified-for-reuse components for returned systems. Physical properties and age are used to assess the components' residual lifetimes. Only components in the acceptable state are qualified for reuse. For a large number of components to be sorted only the ones whose ages are below a certain threshold are evaluated. This age threshold is estimated so that the proportion of components in the unacceptable states does not exceed the standard significance level. The proposed approach has been applied to the end of life of electric-powered wheelchair batteries. © RAMS Consultants.


Agard B.,Center Interuniversitaire Of Recherche Sur Les Reseaux Dentreprise | Agard B.,Ecole Polytechnique de Montréal | Bassetto S.,Ecole Polytechnique de Montréal
International Journal of Production Research | Year: 2013

The purpose of this article is to help managers early in the design of new product families. Based on product structures, sales forecasts, and constraints imposed by the marketplace, like quality and cost, the proposed method selects the product modules that meet customer requirements for the products, while respecting those constraints. The proposal includes a single-level module design formulation that considers quality and cost simultaneously. The method for testing the proposed algorithm is based on a case study of an electro-mechanical assembly device (headlamp). The performance of the algorithm is compared to that of the zero module case, where often the constraint problem cannot be resolved. The main result is a model and an algorithm that optimise quality and cost under the constraints of quality and cost. It shows what modules to manufacture, in what quantities, and in which products to use them. The output also provides the predicted quality and cost, based on improvements made to the modules. To conclude, this research enables the joint optimisation of quality and cost by defining the modules to be manufactured. It provides input for managers seeking modules designed for their supply chain. The algorithm provides key input for managing production ramp-up. © 2013 Copyright Taylor and Francis Group, LLC.

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