- Email: [email protected]
The Youngest OR in Europe
Available online at www.sciencedirect.com
European Journal of Operational Research 189 (2008) 579–582 www.elsevier.com/locate/ejor
Editorial
The Youngest OR in Europe
1. Introduction This special issue titled ‘‘The Youngest OR in Europe’’ is devoted to the young researchers and practitioners in all areas of Operational Research. Therefore, it contains a small portion of the scientific work of the promising future generation of Operational Researchers. Specific to this special issue are the requirements that the first author of each submitted paper had to satisfy at the time of submission. More specifically, the first author had to be either: (1) a pre-doctoral student, (2) a doctoral researcher with no more than two years of post-doctoral experience or (3) a practitioner with no more than two years of professional experience. Another differentiating characteristic of this issue is the fact that there is no specific topic, i.e., all papers inside a wide understanding of the OR field were welcomed. The main source of papers for this special issue has been the third edition of the ORP3 conference, held in Valencia, from the 6th to the 10th of September, 2005 (www.cfp.upv.es/orp3). This ORP3 conference is very special and is commented below.
One of the main activities of the ORP3 is the biannual conference. So far there have been three conferences. The first one took place in Paris, France, from the 26th to 29th of September, 2001. The second edition of the ORP3 conference took place in Lambrecht, Germany, from the 21th to the 26th of September, 2003. The third and last ORP3 conference so far was held in Valencia as has been already mentioned. Currently, the fourth edition of the ORP3 is in the works at the time of the writing of this editorial and is planned to be held in Guimara˜es, Portugal, in 2007 (www.orp3.com). Similarly to this special issue, the ORP3 is also devoted to young OR researchers and practitioners and has some specific characteristics:
2. The third edition of the ORP3 conference The ORP3 or ‘‘The Operational Research Peripatetic Post-Graduate Programme’’ is an instrument of EURO (the Association of European OR Societies). The main actors of this programme are the young OR researchers and practitioners. The objective is to promote scientific and social exchanges between the members of the future generation of Operational Researchers both in academia as well as in industry. 0377-2217/$ - see front matter 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.ejor.2006.12.001
• ORP3 is organized by young OR researchers and is dedicated to young doctoral researchers and/or OR analysts. • ORP3 is mainly sponsored by EURO and offers really low registration fees with all meals and accommodation included. • There are no parallel sessions in ORP3. • Selection of participants on the basis of full paper submissions of publishable quality. • Limited number of participants where all of them give a talk about their work in plenary sessions. • Participants also get to chair sessions and to discuss another participant’s work. • Active social events and coffee breaks to promote social interaction between future OR researchers. • Tutorial sessions given by renowned senior speakers. • Possibility of publishing in a special issue of an important international journal.
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Editorial / European Journal of Operational Research 189 (2008) 579–582
This last characteristic of the ORP3 is the main reason of this special issue. However, it should be noted that the special issue was open to all the OR community and, as a matter of fact it contains papers that were not presented at the ORP3 conference. In a general meeting at the EURO conference held in Rhodes, Greece, in July 2004, the Valencian proposal for organizing the ORP3 was approved. Shortly afterwards, the organization of the conference began. The web page was ready by October 2004 and the call for papers for the conference was issued shortly thereafter. By the deadline of February, 2005, a total of 62 papers were received. The scientific committee of ORP3 was composed as follows: David Alcaide Lo´pez de Pablo (Spain), ´ lvarez Javier Alcaraz Soria (Spain), Ramo´n A Valde´s Olaguı´bel (Spain), Denis Bouyssou (France), Fortunato Crespo Abril (Spain), Laureano Escudero Bueno (Spain), Horst W. Hamacher (Ger´ lvarez (Spain), Ethel many), Concepcio´n Maroto A Mokotoff Miguel (Spain), Luis Paquete (Portugal), Jesu´s Pastor Ciurana (Spain), Marie Claude Portmann (France), Joaquı´n Sicilia Rodrı´guez (Spain), Thomas Stu¨tzle (Germany), Rube´n Ruiz Garcı´a (Spain) and Enriqueta Vercher Gonza´lez (Spain). This committee, with the help of 33 additional referees, carefully revised each full paper submitted to the conference in a double-blind process, where each paper was revised by at least two experts. After revisions, a total of 40 papers were accepted for the conference. This number is significantly larger than in previous editions. Hence, this third ORP3 edition has been the largest up to date. Fourteen different countries were represented in the meeting. At the conference, every paper was presented by a young OR researcher in a full 30-min plenary session and another young OR colleague was in charge of chairing the session and the discussion. Lively talks and discussions followed every presentation in a very interested and friendly atmosphere. Apart from the discussions, two prominent and experienced researchers gave tutorials at the conference. More precisely, Thomas Stu¨tzle, from the IRIDIA at the Universite´ Libre de Bruxelles introduced the attendants to metaheuristics in the talk ‘‘Stochastic Local Search Methods’’. A second tutorial, titled ‘‘From Operational Research to Decision Aiding’’ was given by Denis Bouyssou from the CNRS LAMSADE. Denis was also the chair of the first ORP3 conference. These tutorials were aimed to help young researchers understand operations research classic and recent techniques.
We would like to thank Denis Bouyssou and Thomas Stu¨tzle for their valuable contribution to the meeting. ORP3 is a fine EURO instrument that seriously raises the subject of the introduction of future OR scientists to the transfer of knowledge and to the notion of respect towards the work of fellow researchers. 3. The feature issue Shortly after the ORP3 conference, a call of papers for this special issue was sent to as many associations, bodies, mailing lists and researchers as it was possible. The submission deadline was set at the 31st of December, 2005. This allowed researchers all over the world to ready their submissions in response to the open call for papers. A total of 40 papers were received. From these submissions, 10 were from young OR researchers that did not attend the ORP3 conference. In those cases, the guest editors asked for the necessary documentation in order to comply with the conditions of the special issue. A large number of submissions corresponded to ORP3 attendants. In this case, all the papers were thoroughly improved and extended versions of those presented at the conference. Authors reworked the papers following the comments of the referees and also the feedback and constructive comments received at the conference by both young and senior researchers. This is a very much desirable outcome of the ORP3 meeting. All papers received were strictly reviewed according to the standards of the European Journal of Operational Research. More precisely, all papers were promptly sent to a minimum of three expert referees. The guest editors took special care in concealing the names of both sides (referees and authors) which ensured a double-blind review process. The review process has been extremely difficult for many reasons. First, the number of received submissions was larger than anticipated. Second, being an open topic, the guest editors received papers from many different areas inside OR and the search for suitable referees was not an easy task. All this resulted in an extremely time consuming process. Exactly, a total of 201 different referees participated in the revision process that lasted for 10 long months. In this period, most papers underwent two or three thorough revisions. This special issue contains a total of 16 papers that passed this strict revision process, which amounts to a 60% rejection rate.
Editorial / European Journal of Operational Research 189 (2008) 579–582
The papers that form this special issue represent the current research work that our young OR scientists are carrying out. We find works about classical OR problems and/or techniques that are tackled with novel approaches like the traveling salesman problem, dynamic programming, non-linear programming, branch and bound, sequencing and scheduling, inventory theory, decision analysis and forecasting. Likewise, the issue also contains contributions in interesting recent techniques that are experiencing a number of applications like metaheuristics, fuzzy set theory and digital analysis. As regards applications, the papers published in this special issue allow for better solutions to problems of paramount economic and social importance like those appearing in health services, public transportation, electric distribution, environment, personnel selection, manufacturing systems and operations management. A brief summary of the contents of this special issue is now presented. The paper ‘‘Testing the accuracy of employeereported data: An inexpensive alternative approach to traditional methods’’ coauthored by Douglas N. Hales, V. Sridharan, Abirami Radhakrishnan, Satya S. Chakravorty and Samia M. Siha, presents a technique dubbed as ‘‘digital analysis’’ for the sole purpose of identifying self-reported data at companies that might be subject to manipulation. The work ‘‘Modelling impacts of cropping systems: demands and solutions for DEX methodology’’ by Martin Zˇnidarsˇicˇ, Marko Bohanec and Blazˇ Zupan studies a decision problem arising in the agronomic field when dealing with conventional and genetically modified crops. The classical facility layout problem is dealt with in the work ‘‘Exact solution procedures for the balanced unidirectional cyclic Layout Prob_ Kuban Altınel. More ¨ ncan and I. lem’’ by Temel O precisely, the authors optimally solve a layout variation where facilities are laid in closed loop configurations. In a totally different direction goes the paper ‘‘Modelling and forecasting mortality in Spain’’ where the authors A. Debo´n, F. Montes and P. Puig study Lee-Carter dynamic life tables with advanced and novel non-parametric bootstrapping statistical techniques. Another interesting problem is studied by Enrico Malaguti and Paolo Toth in the paper ‘‘An evolutionary approach for bandwidth multicoloring problems’’ where the authors tackle a generalization of the well known vertex coloring problem. In ‘‘A branch-and-price approach for integrating nurse and surgery scheduling’’, Jeroen
581
Belie¨n and Erik Demeulemeester study an important problem that results from the joint scheduling of nurses and operating rooms. In the same human resource management field, L. Cano´s and V. Liern study in ‘‘Soft computing-based aggregation methods for human resource management’’ the personnel selection problem with advanced techniques. The paper ‘‘An efficient approach for solving the lot-sizing problem with time-varying storage capacities’’, J. Gutie´rrez, A. Seden˜o-Noda, M. Colebrook and J. Sicilia deal with the well known dynamic lotsizing problem with the additional characteristic that the storage capacity varies throughout the planning horizon. Another very interesting problem is studied in ‘‘Multiobjective service restoration in electric distribution networks using a local search based heuristic’’ where the authors Vinı´cius Jacques Garcia and Paulo Morelato Franc¸a propose solution techniques for restoring power outages minimizing the conflicting objectives of restoration cost and load not supplied. Alberto Olivares, Javier M. Moguerza and Francisco J. Prieto propose a new algorithm for nonconvex unconstrained optimization problems in ‘‘Nonconvex optimization using negative curvature within a modified linesearch’’. The issue of robustness in project scheduling is approached in the paper ‘‘Proactive heuristic procedures for robust project scheduling: an experimental analysis’’ by Stijn Van de Vonder, Erik Demeulemeester and Willy Herroelen. Michele Ciavotta, Paolo Detti, Carlo Meloni and Marco Pranzo present an interesting realistic bi-objective scheduling problem along with some heuristic techniques in ‘‘A bi-objective coordination setup problem in a two-stage production system’’. The special issue contains two very interesting contributions in the active research field of public transportation. In ‘‘Real time management of a metro rail terminus’’, Marta Flamini and Dario Pacciarelli study the routing of incoming trains in a station and the scheduling of their departure times from a bi-objective perspective. The second contribution in this area comes from Ge´raldine Heilporn, Luigi De Giovanni and Martine Labbe´ in the paper ‘‘Optimization models for the single delay management problem in public transportation’’ where they study the wait or depart decisions in intermodal transportation networks. Finally, the special issue also contains two papers that study the well known traveling salesman problem and its variants. Marcel Turkensteen, Diptesh Ghosh, Boris Goldengorin and Gerard Sierksma study the asymmetric variant of this problem in
582
Editorial / European Journal of Operational Research 189 (2008) 579–582
‘‘Tolerance-based branch and bound algorithms for the ATSP’’. Finally, the last paper in this issue considers the same problem with the addition of time windows and time-dependent travel times and costs. This last paper is titled ‘‘An asymmetric TSP with time windows and with time-dependent travel times and costs: an exact solution through a graph transformation’’ is coauthored by Jose´ Albiach, Jose´ Marı´a Sanchis and David Soler. As can bee seen, the special issue contains contributions to many different fields inside OR with the additional characteristic that the first authors of each paper are young OR scientists who will soon become established researchers in the field. Acknowledgements This special issue would not have been possible without the help of many dedicated and involved individuals. The guest editors would like to thank all other members of both the scientific as well as organization committees of the ORP3 conference as well as all the sponsors that contributed to it. More specifically, we would like to thank the EURO, SEIO (Spanish Statistics and OR Society) and the following bodies of the Polytechnic University of Valencia (UPV): Vicerrectorate for Research, Innovation and Development (VIDI), the Continuous Training Centre (CFP), the school of business administration and management (FADE) and the Applied Statistics and Operations Research, and quality Department (DEIOAC) for all the support provided. We would like to thank Roman Słowin´ski, Co-ordinating Editor of the European Journal of
Operational Research for all the help and guidance in the preparation of this special issue. Our most sincere thanks go also to the hundreds of referees that have provided us with timely and comprehensive reports. Without their help this special issue would have not been a reality. Lastly, by all accounts we would also like to thank the young OR researchers that contributed with their hard work to this special issue. Young OR researchers will, in the next decades, contribute to the improvement of our society by increasing the competitiveness of companies, public services and organizations while keeping the professional ethics that characterizes experts in the field. We sincerely hope that we have helped in creating the necessary links among you all for a better OR future in Europe. Rube´n Ruiz Grupo de Sistemas de Optimizacio´n Aplicada, Instituto Tecnolo´gico de Informa´tica, Universidad Polite´cnica de Valencia, Edificio I-3, Camino de Vera S/N, 46021 Valencia, Spain E-mail addresses: [email protected], [email protected] Concepcio´n Maroto Grupo de Investigacio´n Operativa GIO, Departamento de Estadı´stica e Investigacio´n Operativa Aplicadas y Calidad, Universidad Polite´cnica de Valencia, Camino de Vera S/N, 46021 Valencia, Spain E-mail address: [email protected]
European Journal of Operational Research 189 (2008) 579–582 www.elsevier.com/locate/ejor
Editorial
The Youngest OR in Europe
1. Introduction This special issue titled ‘‘The Youngest OR in Europe’’ is devoted to the young researchers and practitioners in all areas of Operational Research. Therefore, it contains a small portion of the scientific work of the promising future generation of Operational Researchers. Specific to this special issue are the requirements that the first author of each submitted paper had to satisfy at the time of submission. More specifically, the first author had to be either: (1) a pre-doctoral student, (2) a doctoral researcher with no more than two years of post-doctoral experience or (3) a practitioner with no more than two years of professional experience. Another differentiating characteristic of this issue is the fact that there is no specific topic, i.e., all papers inside a wide understanding of the OR field were welcomed. The main source of papers for this special issue has been the third edition of the ORP3 conference, held in Valencia, from the 6th to the 10th of September, 2005 (www.cfp.upv.es/orp3). This ORP3 conference is very special and is commented below.
One of the main activities of the ORP3 is the biannual conference. So far there have been three conferences. The first one took place in Paris, France, from the 26th to 29th of September, 2001. The second edition of the ORP3 conference took place in Lambrecht, Germany, from the 21th to the 26th of September, 2003. The third and last ORP3 conference so far was held in Valencia as has been already mentioned. Currently, the fourth edition of the ORP3 is in the works at the time of the writing of this editorial and is planned to be held in Guimara˜es, Portugal, in 2007 (www.orp3.com). Similarly to this special issue, the ORP3 is also devoted to young OR researchers and practitioners and has some specific characteristics:
2. The third edition of the ORP3 conference The ORP3 or ‘‘The Operational Research Peripatetic Post-Graduate Programme’’ is an instrument of EURO (the Association of European OR Societies). The main actors of this programme are the young OR researchers and practitioners. The objective is to promote scientific and social exchanges between the members of the future generation of Operational Researchers both in academia as well as in industry. 0377-2217/$ - see front matter 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.ejor.2006.12.001
• ORP3 is organized by young OR researchers and is dedicated to young doctoral researchers and/or OR analysts. • ORP3 is mainly sponsored by EURO and offers really low registration fees with all meals and accommodation included. • There are no parallel sessions in ORP3. • Selection of participants on the basis of full paper submissions of publishable quality. • Limited number of participants where all of them give a talk about their work in plenary sessions. • Participants also get to chair sessions and to discuss another participant’s work. • Active social events and coffee breaks to promote social interaction between future OR researchers. • Tutorial sessions given by renowned senior speakers. • Possibility of publishing in a special issue of an important international journal.
580
Editorial / European Journal of Operational Research 189 (2008) 579–582
This last characteristic of the ORP3 is the main reason of this special issue. However, it should be noted that the special issue was open to all the OR community and, as a matter of fact it contains papers that were not presented at the ORP3 conference. In a general meeting at the EURO conference held in Rhodes, Greece, in July 2004, the Valencian proposal for organizing the ORP3 was approved. Shortly afterwards, the organization of the conference began. The web page was ready by October 2004 and the call for papers for the conference was issued shortly thereafter. By the deadline of February, 2005, a total of 62 papers were received. The scientific committee of ORP3 was composed as follows: David Alcaide Lo´pez de Pablo (Spain), ´ lvarez Javier Alcaraz Soria (Spain), Ramo´n A Valde´s Olaguı´bel (Spain), Denis Bouyssou (France), Fortunato Crespo Abril (Spain), Laureano Escudero Bueno (Spain), Horst W. Hamacher (Ger´ lvarez (Spain), Ethel many), Concepcio´n Maroto A Mokotoff Miguel (Spain), Luis Paquete (Portugal), Jesu´s Pastor Ciurana (Spain), Marie Claude Portmann (France), Joaquı´n Sicilia Rodrı´guez (Spain), Thomas Stu¨tzle (Germany), Rube´n Ruiz Garcı´a (Spain) and Enriqueta Vercher Gonza´lez (Spain). This committee, with the help of 33 additional referees, carefully revised each full paper submitted to the conference in a double-blind process, where each paper was revised by at least two experts. After revisions, a total of 40 papers were accepted for the conference. This number is significantly larger than in previous editions. Hence, this third ORP3 edition has been the largest up to date. Fourteen different countries were represented in the meeting. At the conference, every paper was presented by a young OR researcher in a full 30-min plenary session and another young OR colleague was in charge of chairing the session and the discussion. Lively talks and discussions followed every presentation in a very interested and friendly atmosphere. Apart from the discussions, two prominent and experienced researchers gave tutorials at the conference. More precisely, Thomas Stu¨tzle, from the IRIDIA at the Universite´ Libre de Bruxelles introduced the attendants to metaheuristics in the talk ‘‘Stochastic Local Search Methods’’. A second tutorial, titled ‘‘From Operational Research to Decision Aiding’’ was given by Denis Bouyssou from the CNRS LAMSADE. Denis was also the chair of the first ORP3 conference. These tutorials were aimed to help young researchers understand operations research classic and recent techniques.
We would like to thank Denis Bouyssou and Thomas Stu¨tzle for their valuable contribution to the meeting. ORP3 is a fine EURO instrument that seriously raises the subject of the introduction of future OR scientists to the transfer of knowledge and to the notion of respect towards the work of fellow researchers. 3. The feature issue Shortly after the ORP3 conference, a call of papers for this special issue was sent to as many associations, bodies, mailing lists and researchers as it was possible. The submission deadline was set at the 31st of December, 2005. This allowed researchers all over the world to ready their submissions in response to the open call for papers. A total of 40 papers were received. From these submissions, 10 were from young OR researchers that did not attend the ORP3 conference. In those cases, the guest editors asked for the necessary documentation in order to comply with the conditions of the special issue. A large number of submissions corresponded to ORP3 attendants. In this case, all the papers were thoroughly improved and extended versions of those presented at the conference. Authors reworked the papers following the comments of the referees and also the feedback and constructive comments received at the conference by both young and senior researchers. This is a very much desirable outcome of the ORP3 meeting. All papers received were strictly reviewed according to the standards of the European Journal of Operational Research. More precisely, all papers were promptly sent to a minimum of three expert referees. The guest editors took special care in concealing the names of both sides (referees and authors) which ensured a double-blind review process. The review process has been extremely difficult for many reasons. First, the number of received submissions was larger than anticipated. Second, being an open topic, the guest editors received papers from many different areas inside OR and the search for suitable referees was not an easy task. All this resulted in an extremely time consuming process. Exactly, a total of 201 different referees participated in the revision process that lasted for 10 long months. In this period, most papers underwent two or three thorough revisions. This special issue contains a total of 16 papers that passed this strict revision process, which amounts to a 60% rejection rate.
Editorial / European Journal of Operational Research 189 (2008) 579–582
The papers that form this special issue represent the current research work that our young OR scientists are carrying out. We find works about classical OR problems and/or techniques that are tackled with novel approaches like the traveling salesman problem, dynamic programming, non-linear programming, branch and bound, sequencing and scheduling, inventory theory, decision analysis and forecasting. Likewise, the issue also contains contributions in interesting recent techniques that are experiencing a number of applications like metaheuristics, fuzzy set theory and digital analysis. As regards applications, the papers published in this special issue allow for better solutions to problems of paramount economic and social importance like those appearing in health services, public transportation, electric distribution, environment, personnel selection, manufacturing systems and operations management. A brief summary of the contents of this special issue is now presented. The paper ‘‘Testing the accuracy of employeereported data: An inexpensive alternative approach to traditional methods’’ coauthored by Douglas N. Hales, V. Sridharan, Abirami Radhakrishnan, Satya S. Chakravorty and Samia M. Siha, presents a technique dubbed as ‘‘digital analysis’’ for the sole purpose of identifying self-reported data at companies that might be subject to manipulation. The work ‘‘Modelling impacts of cropping systems: demands and solutions for DEX methodology’’ by Martin Zˇnidarsˇicˇ, Marko Bohanec and Blazˇ Zupan studies a decision problem arising in the agronomic field when dealing with conventional and genetically modified crops. The classical facility layout problem is dealt with in the work ‘‘Exact solution procedures for the balanced unidirectional cyclic Layout Prob_ Kuban Altınel. More ¨ ncan and I. lem’’ by Temel O precisely, the authors optimally solve a layout variation where facilities are laid in closed loop configurations. In a totally different direction goes the paper ‘‘Modelling and forecasting mortality in Spain’’ where the authors A. Debo´n, F. Montes and P. Puig study Lee-Carter dynamic life tables with advanced and novel non-parametric bootstrapping statistical techniques. Another interesting problem is studied by Enrico Malaguti and Paolo Toth in the paper ‘‘An evolutionary approach for bandwidth multicoloring problems’’ where the authors tackle a generalization of the well known vertex coloring problem. In ‘‘A branch-and-price approach for integrating nurse and surgery scheduling’’, Jeroen
581
Belie¨n and Erik Demeulemeester study an important problem that results from the joint scheduling of nurses and operating rooms. In the same human resource management field, L. Cano´s and V. Liern study in ‘‘Soft computing-based aggregation methods for human resource management’’ the personnel selection problem with advanced techniques. The paper ‘‘An efficient approach for solving the lot-sizing problem with time-varying storage capacities’’, J. Gutie´rrez, A. Seden˜o-Noda, M. Colebrook and J. Sicilia deal with the well known dynamic lotsizing problem with the additional characteristic that the storage capacity varies throughout the planning horizon. Another very interesting problem is studied in ‘‘Multiobjective service restoration in electric distribution networks using a local search based heuristic’’ where the authors Vinı´cius Jacques Garcia and Paulo Morelato Franc¸a propose solution techniques for restoring power outages minimizing the conflicting objectives of restoration cost and load not supplied. Alberto Olivares, Javier M. Moguerza and Francisco J. Prieto propose a new algorithm for nonconvex unconstrained optimization problems in ‘‘Nonconvex optimization using negative curvature within a modified linesearch’’. The issue of robustness in project scheduling is approached in the paper ‘‘Proactive heuristic procedures for robust project scheduling: an experimental analysis’’ by Stijn Van de Vonder, Erik Demeulemeester and Willy Herroelen. Michele Ciavotta, Paolo Detti, Carlo Meloni and Marco Pranzo present an interesting realistic bi-objective scheduling problem along with some heuristic techniques in ‘‘A bi-objective coordination setup problem in a two-stage production system’’. The special issue contains two very interesting contributions in the active research field of public transportation. In ‘‘Real time management of a metro rail terminus’’, Marta Flamini and Dario Pacciarelli study the routing of incoming trains in a station and the scheduling of their departure times from a bi-objective perspective. The second contribution in this area comes from Ge´raldine Heilporn, Luigi De Giovanni and Martine Labbe´ in the paper ‘‘Optimization models for the single delay management problem in public transportation’’ where they study the wait or depart decisions in intermodal transportation networks. Finally, the special issue also contains two papers that study the well known traveling salesman problem and its variants. Marcel Turkensteen, Diptesh Ghosh, Boris Goldengorin and Gerard Sierksma study the asymmetric variant of this problem in
582
Editorial / European Journal of Operational Research 189 (2008) 579–582
‘‘Tolerance-based branch and bound algorithms for the ATSP’’. Finally, the last paper in this issue considers the same problem with the addition of time windows and time-dependent travel times and costs. This last paper is titled ‘‘An asymmetric TSP with time windows and with time-dependent travel times and costs: an exact solution through a graph transformation’’ is coauthored by Jose´ Albiach, Jose´ Marı´a Sanchis and David Soler. As can bee seen, the special issue contains contributions to many different fields inside OR with the additional characteristic that the first authors of each paper are young OR scientists who will soon become established researchers in the field. Acknowledgements This special issue would not have been possible without the help of many dedicated and involved individuals. The guest editors would like to thank all other members of both the scientific as well as organization committees of the ORP3 conference as well as all the sponsors that contributed to it. More specifically, we would like to thank the EURO, SEIO (Spanish Statistics and OR Society) and the following bodies of the Polytechnic University of Valencia (UPV): Vicerrectorate for Research, Innovation and Development (VIDI), the Continuous Training Centre (CFP), the school of business administration and management (FADE) and the Applied Statistics and Operations Research, and quality Department (DEIOAC) for all the support provided. We would like to thank Roman Słowin´ski, Co-ordinating Editor of the European Journal of
Operational Research for all the help and guidance in the preparation of this special issue. Our most sincere thanks go also to the hundreds of referees that have provided us with timely and comprehensive reports. Without their help this special issue would have not been a reality. Lastly, by all accounts we would also like to thank the young OR researchers that contributed with their hard work to this special issue. Young OR researchers will, in the next decades, contribute to the improvement of our society by increasing the competitiveness of companies, public services and organizations while keeping the professional ethics that characterizes experts in the field. We sincerely hope that we have helped in creating the necessary links among you all for a better OR future in Europe. Rube´n Ruiz Grupo de Sistemas de Optimizacio´n Aplicada, Instituto Tecnolo´gico de Informa´tica, Universidad Polite´cnica de Valencia, Edificio I-3, Camino de Vera S/N, 46021 Valencia, Spain E-mail addresses: [email protected], [email protected] Concepcio´n Maroto Grupo de Investigacio´n Operativa GIO, Departamento de Estadı´stica e Investigacio´n Operativa Aplicadas y Calidad, Universidad Polite´cnica de Valencia, Camino de Vera S/N, 46021 Valencia, Spain E-mail address: [email protected]