The stratified p-center problem

This work presents an extension of the p-center problem. In this new model, called Stratified p-Center Problem (SpCP), the demand is concentrated in a set of sites and the population of these sites is divided into different strata depending on the kind of service that they require. The aim is to locate p centers to cover the different types of services demanded minimizing the weighted average of the largest distances associated with each of the different strata. In addition, it is considered that more than one stratum can be present at each site. Different formulations, valid inequalities and preprocessings are developed and compared for this problem. An application of this model is presented in order to implement a heuristic approach based on the Sample Average Approximation method (SAA) for solving the probabilistic p-center problem in an efficient way.Comment: 32 pages, 1 pictur

The Incremental Cooperative Design of Preventive Healthcare Networks

This document is the Accepted Manuscript version of the following article: Soheil Davari, 'The incremental cooperative design of preventive healthcare networks', Annals of Operations Research, first published online 27 June 2017. Under embargo. Embargo end date: 27 June 2018. The final publication is available at Springer via http://dx.doi.org/10.1007/s10479-017-2569-1.In the Preventive Healthcare Network Design Problem (PHNDP), one seeks to locate facilities in a way that the uptake of services is maximised given certain constraints such as congestion considerations. We introduce the incremental and cooperative version of the problem, IC-PHNDP for short, in which facilities are added incrementally to the network (one at a time), contributing to the service levels. We first develop a general non-linear model of this problem and then present a method to make it linear. As the problem is of a combinatorial nature, an efficient Variable Neighbourhood Search (VNS) algorithm is proposed to solve it. In order to gain insight into the problem, the computational studies were performed with randomly generated instances of different settings. Results clearly show that VNS performs well in solving IC-PHNDP with errors not more than 1.54%.Peer reviewe

JIEM's fourth year: Present status and future avenues

[EN] This editorial reflects some relevant information about the evolution of JIEM during 2011, together with novel features that have been implemented so far or which are planned to be realized.Fernandez, V.; Albareda-Sambola, M.; Simo, P.; Sallan, JM.; Enache, M.; Mula Bru, J.; De La Fuente, V. (2012). JIEM's fourth year: Present status and future avenues. Journal of Industrial Engineering and Management. 5(1):1-3. doi:10.3926/jiem.500S135

Design of hybrid multimodal logistic hub network with postponement strategy

This paper aims at suggesting a method allowing to design a logistic hub network in the context of postponement strategy, postponement being performed in hubs having industrial facilities in addition to logistic ones. We propose a two-stage mathematical mixed integer linear programming model for: 1) logistic hub network design 2) postponement location on the designed hub network. The suggested model manages characteristics not yet taken into account simultaneously in the literature: hierarchical logistic structure, postponement strategy, multi-commodity, multi-packaging of goods (raw materials or components vs. final products), multi-period planning. The solutions are compared through services levels and logistic costs