Documents disponibles écrits par cet auteur

A novel maximum dispersion territory design model arising in the implementation of the WEEE-directive / E. Fernández in Journal of the operational research society (JORS), Vol. 61 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 3 (Mars 2010) . - pp. 503–514 Titre : A novel maximum dispersion territory design model arising in the implementation of the WEEE-directive Type de document : texte imprimé Auteurs : E. Fernández, Auteur ; J. Kalcsics, Auteur ; S. Nickel, Auteur Année de publication : 2011 Article en page(s) : pp. 503–514 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Heuristics  Optimization  Logistics  Recycling  Territory  design Index. décimale : 001.424 Résumé : The problem discussed in this paper is motivated by the new recycling directive Waste Electrical and Electronic Equipment of the European Commission. The core of this law is, that each company which sells electrical or electronic equipment in a European country has the obligation to recollect and recycle an amount of returned items which is proportional to its market share. To assign collection stations to companies, in Germany for one product type a territory design approach is planned. However, in contrast to classical territory design, the territories should be geographically as dispersed as possible to avoid that a company, respectively its logistics provider responsible for the recollection, gains a monopoly in some region. First, we identify an appropriate measure for the dispersion of a territory. Afterwards, we present a first mathematical programming model for this new problem as well as a solution method based on the Greedy Randomized Adaptive Search Procedure methodology. Extensive computational results illustrate the suitability of the model and assess the effectiveness of the heuristic. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n3/abs/jors200970a.html [article] A novel maximum dispersion territory design model arising in the implementation of the WEEE-directive [texte imprimé] / E. Fernández, Auteur ; J. Kalcsics, Auteur ; S. Nickel, Auteur . - 2011 . - pp. 503–514. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 3 (Mars 2010) . - pp. 503–514 Mots-clés : Heuristics  Optimization  Logistics  Recycling  Territory  design Index. décimale : 001.424 Résumé : The problem discussed in this paper is motivated by the new recycling directive Waste Electrical and Electronic Equipment of the European Commission. The core of this law is, that each company which sells electrical or electronic equipment in a European country has the obligation to recollect and recycle an amount of returned items which is proportional to its market share. To assign collection stations to companies, in Germany for one product type a territory design approach is planned. However, in contrast to classical territory design, the territories should be geographically as dispersed as possible to avoid that a company, respectively its logistics provider responsible for the recollection, gains a monopoly in some region. First, we identify an appropriate measure for the dispersion of a territory. Afterwards, we present a first mathematical programming model for this new problem as well as a solution method based on the Greedy Randomized Adaptive Search Procedure methodology. Extensive computational results illustrate the suitability of the model and assess the effectiveness of the heuristic. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n3/abs/jors200970a.html

Stochastic analysis of ordered median problems / Z. Drezner in Journal of the operational research society (JORS), Vol. 63 N° 11 (Novembre 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 11 (Novembre 2012) . - pp. 1578–1588 Titre : Stochastic analysis of ordered median problems Type de document : texte imprimé Auteurs : Z. Drezner, Auteur ; S. Nickel, Auteur ; H.-P. Ziegler, Auteur Année de publication : 2012 Article en page(s) : pp. 1578–1588 Note générale : operational research Langues : Anglais (eng) Mots-clés : location;  stochastic  models;  ordered  median;  order  statistics Index. décimale : 001.424 Résumé : Many location problems can be expressed as ordered median objective. In this paper, we investigate the ordered median objective when the demand points are generated in a circle. We find the mean and variance of the kth distance from the centre of the circle and the correlation matrix between all pairs of ordered distances. By applying these values, we calculate the mean and variance of any ordered median objective and the correlation coefficient between two ordered median objectives. The usefulness of the results is demonstrated by calculating various probabilities such as: What is the probability that the mean distance is greater than the truncated mean distance? What is the probability that the maximum distance is greater than 0.9? What is the probability that the range of distances is greater than 0.8? An analysis of an illustrative example also demonstrates the usefulness of the analysis. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n11/abs/jors20122a.html [article] Stochastic analysis of ordered median problems [texte imprimé] / Z. Drezner, Auteur ; S. Nickel, Auteur ; H.-P. Ziegler, Auteur . - 2012 . - pp. 1578–1588. operational research Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 11 (Novembre 2012) . - pp. 1578–1588 Mots-clés : location;  stochastic  models;  ordered  median;  order  statistics Index. décimale : 001.424 Résumé : Many location problems can be expressed as ordered median objective. In this paper, we investigate the ordered median objective when the demand points are generated in a circle. We find the mean and variance of the kth distance from the centre of the circle and the correlation matrix between all pairs of ordered distances. By applying these values, we calculate the mean and variance of any ordered median objective and the correlation coefficient between two ordered median objectives. The usefulness of the results is demonstrated by calculating various probabilities such as: What is the probability that the mean distance is greater than the truncated mean distance? What is the probability that the maximum distance is greater than 0.9? What is the probability that the range of distances is greater than 0.8? An analysis of an illustrative example also demonstrates the usefulness of the analysis. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n11/abs/jors20122a.html