Heuristic algorithms for the unrelated parallel machine scheduling problem with one scarce additional resource

[EN] In this paper, we study the unrelated parallel machine scheduling problem with one scarce additional resource to minimise the maximum completion time of the jobs or makespan. Several heuristics are proposed following two strategies: the first one is based on the consideration of the resource constraint during the whole solution construction process. The second one starts from several assignment rules without considering the resource constraint, and repairs the non feasible assignments in order to obtain a feasible solution. Several computation experiments are carried out over an extensive benchmark. A comparative evaluation against previously proposed mathematical models and matheuristics (combination of mathematical models and heuristics) is carried out. From the results, we can conclude that our methods outperform the existing ones, and the second strategy performs better, especially for large instances. (C) 2017 Elsevier Ltd. All rights reserved.The authors are supported by the Spanish Ministry of Economy and Competitiveness, under the projects "SCHEYARD - Optimization of Scheduling Problems in Container Yards" (No. DPI2015-65895-R) and "OPTEMAC - Optimizacion de Procesos en Terminales Maritimas de Contenedores" (No. DPI2014-53665-P), all of them partially financed with FEDER funds. The authors are also partially supported by the EU Horizon 2020 research and innovation programme under grant agreement no. 731932 "Transforming Transport: Big Data Value in Mobility and Logistics". Interested readers can download contents from http://soa.iti.es, like the instances used and a software for generating further instances. Source codes are available upon justified request from the authors.Villa Juliá, MF.; Vallada Regalado, E.; Fanjul Peyró, L. (2018). Heuristic algorithms for the unrelated parallel machine scheduling problem with one scarce additional resource. Expert Systems with Applications. 93:28-38. https://doi.org/10.1016/j.eswa.2017.09.054S28389

Flowshop with additional resources during setups: Mathematical models and a GRASP algorithm

[EN] Machine scheduling problems arise in many production processes, and are something that needs to be consider when optimizing the supply chain. Among them, flowshop scheduling problems happen when a number of jobs have to be sequentially processed by a number of machines. This paper addressees, for the first time, the Permutation Flowshop Scheduling problem with additional Resources during Setups (PFSR-S). In this problem, in addition to the standard permutation flowshop constraints, each machine requires a setup between the processing of two consecutive jobs. A number of additional and scarce resources, e.g. operators, are needed to carry out each setup. Two Mixed Integer Linear Programming formulations and an exact algorithm are proposed to solve the PFSR-S. Due to its complexity, these approaches can only solve instances of small size to optimality. Therefore, a GRASP metaheuristic is also proposed which provides solutions for much larger instances. All the methods designed for the PFSR-S in this paper are computationally tested over a benchmark of instances adapted from the literature. The results obtained show that the GRASP metaheuristic finds good quality solutions in short computational times.Juan C. Yepes-Borrero acknowledges financial support by Colfuturo under program Credito-Beca grant number 201503877 and from ElInstituto Colombiano de Credito Educativo y Estudios Tecnicos en el Exterior - ICETEX under program Pasaporte a la ciencia - Doctor-ado, Foco-reto pais 4.2.3, grant number 3568118. This research hasbeen partially supported by the Agencia Estatal de Investigacion (AEI)and the European Regional Development's fund (ERDF): PID2020-114594GB-C21; Regional Government of Andalusia: projects FEDER-US-1256951, AT 21_00032, and P18-FR-1422; Fundacion BBVA: project Netmeet Data (Ayudas Fundacion BBVA a equipos de investigacioncientifica 2019). The authors are partially supported by Agencia Valenciana de la Innovacion (AVI) under the project ireves (innovacionen vehiculos de emergencia sanitaria): una herramienta inteligente dedecision'' (No. INNACC/2021/26) partially financed with FEDER funds(interested readers can visit http://ireves.upv.es), and by the Spanish Ministry of Science and Innovation under the project OPRES-RealisticOptimization in Problems in Public Health'' (No. PID2021-124975OB-I00), partially financed with FEDER funds. Part of the authors aresupported by the Faculty of Business Administration and Managementat Universitat Politecnica de ValenciaYepes-Borrero, JC.; Perea, F.; Villa Juliá, MF.; Vallada Regalado, E. (2023). Flowshop with additional resources during setups: Mathematical models and a GRASP algorithm. Computers & Operations Research. 154. https://doi.org/10.1016/j.cor.2023.10619215

Desarrollo de una metodología para la formación y evaluación “continua” en pensamiento crítico

[EN] In this study, we shall describe a teaching experience carried out by a group of lecturers in the Statistics Department. These lecturers are involved in the training and assessment of “critical thinking” skills as part of the institutional project centred on generic skills at the Universitat Politècnica de València. The objective of this experience was to promote the understanding, development and application of the critical thinking skills in the students. Different activities linked to the abilities involved in critical thinking are proposed to the students throughout the academic year. The activities require ongoing assessment from the formative point of view. Thus, the students are aware of their own progress. Additionally, students are evaluated in the exams with questions in different formats (PoliformaT exams, tests and peer review). Suitable materials and activities for training and assessment of critical thinking have been developed. Finally the teaching staff and the students’ opinions have been collected through surveys.[ES] En este trabajo se presenta la experiencia realizada por un grupo de profesores del Departamento de Estadística en diversas asignaturas que son punto de control de la competencia "Pensamiento Crítico”. El objetivo de la experiencia era guiar a los alumnos para que entendiesen el pensamiento crítico, lo desarrollasen y lo aplicasen. Durante el curso los alumnos han realizado actividades que trabajan diferentes habilidades vinculadas con dicha competencia. Estas actividades han sido evaluadas de tal manera que desde el punto de vista formativo, el alumno sea consciente de su progreso en la competencia. Adicionalmente se les ha evaluado en los exámenes con cuestiones bajo formatos diversos (exámenes PoliformaT, preguntas en pruebas escritas y corrección por pares). Se han creado materiales y actividades adaptadas para la formación y evaluación del pensamiento crítico y a través de encuestas se ha constatado que el profesorado y el alumnado ha valorado positivamente la metodología empleada.Vidal Puig, S.; Barceló Cerdá, S.; Calduch Llosa, Á.; Debón Aucejo, AM.; Calduch Losa, MDLA.; Villa Juliá, MF. (2018). Desarrollo de una metodología para la formación y evaluación “continua” en pensamiento crítico. En IN-RED 2018. IV Congreso Nacional de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 1462-1476. https://doi.org/10.4995/INRED2018.2018.8736OCS1462147

Secuenciación heurística de un proyecto con restricciones temporales

El presente trabajo aborda el análisis de un problema real del mantenimiento que una compañía aeronáutica debe practicar sobre una flota de aviones del tipo Boeing-747. En primer lugar analizamos en qué consiste dicho mantenimiento, los elementos que lo definen y los objetivos que se persiguen. A continuación estudiamos sus similitudes y diferencias con el RCPS (Resource Constrained Project Scheduling), un modelo clásico aplicado a este tipo de problemas. Entre estas diferencias se encuentran la existencia de restricciones temporales para la secuenciación de determinadas tareas así como otros tipos especiales de relaciones entre las actividades además de las clásicas de precedencia. Concretamos, finalmente, la metodología a aplicar para abordar el problema planteado

Minimizing weighted earliness-tardiness on parallel machines using hybrid metaheuristics

We consider the problem of scheduling a set of jobs on a set of identical parallel machines where the objective is to minimize the total weighted earliness and tardiness penalties with respect to a common due date. We propose a hybrid heuristic algorithm for constructing good solutions, combining priority rules for assigning jobs to machines and a local search with exact procedures for solving the one-machine subproblems. These solutions are then used in two metaheuristic frameworks, Path Relinking and Scatter Search, to obtain high quality solutions for the problem. The algorithms are tested on a large number of test instances to assess the efficiency of the proposed strategies. The results show that our algorithms consistently outperform the best reported results for this problem.This study has been partially supported by the Spanish Ministry of Science and Technology, DPI2011-24977, and by Generalitat Valenciana, PROMETEO/2013/049.Alvarez Valdes, R.; Tamarit, J.; Villa Juliá, MF. (2015). Minimizing weighted earliness-tardiness on parallel machines using hybrid metaheuristics. Computers and Operations Research. 54:1-11. doi:10.1016/j.cor.2014.08.020S1115

Enriched metaheuristics for the resource constrained unrelated parallel machine scheduling problem

[EN] A Scatter Search algorithm together with an enriched Scatter Search and an enriched Iterated Greedy for the unrelated parallel machine problem with one additional resource are proposed in this paper. The optimisation objective is to minimise the maximum completion of the jobs on the machines, that is, the makespan. All the proposed methods start from the best known heuristic for the same problem. Non feasible solutions are allowed in all the methods and a Repairing Mechanism is applied to obtain a feasible solution from a resource constraint point of view. All the proposed algorithms apply different local search procedures based on insertion, swap and restricted neighbourhoods. Computational experiments are carried out using an exhaustive benchmark of instances. After analysing the results, we can conclude that the enriched methods obtain superior results, outperforming the best known solutions for the same problem.The authors are supported by the Spanish Ministry of Economy and Competitiveness, under the projects "SCHEYARD - Optimization of Scheduling Problems in Container Yards" (No. DPI201565895-R) and "OPTEMAC -Optimizacion de Procesos en Terminales Maritimas de Contenedores" (No. DPI2014-53665-P), all of them partially financed with FEDER funds. The authors are also partially supported by the EU Horizon 2020 research and innovation programme under grant agreement no. 731932 "Transforming Transport: Big Data Value in Mobility and Logistics". Interested readers can download contents from http://soa.iti.es, like the instances used and a software for generating further instances. Source codes are available upon justified request from the authors.Vallada Regalado, E.; Villa Juliá, MF.; Fanjul-Peyro, L. (2019). Enriched metaheuristics for the resource constrained unrelated parallel machine scheduling problem. Computers & Operations Research. 111:415-424. https://doi.org/10.1016/j.cor.2019.07.016S41542411

Patterns of mortality in European Union countries and characterizacion according to their mortality indicators

“Estadística Española”, número especial de análisis de la mortalidad; Tercer cuatrimestre de 2016[ES] Las comparaciones de longevidad en diferentes países ayudan a los responsables políticos y a los analistas a evaluar la cantidad de periodos de tiempo y de personas que se han beneficiado de los programas públicos, como la seguridad social y la asistencia sanitaria. El objetivo fundamental de este trabajo es identificar grupos de países de la Unión Europea que tengan comportamientos similares en su mortalidad. Las diferencias entre los grupos serán cuantificadas a través de los indicadores de mortalidad. El trabajo muestra que, teniendo en cuenta la mortalidad, los países de la Unión Europea se pueden agrupar en tres clusters. Uno formado por Alemania, Austria, Bélgica, Dinamarca, España, Finlandia, Francia, Holanda, Irlanda, Italia, Luxemburgo, Portugal, Reino Unido y Suecia. Otro formado por Bulgaria, Polonia, Eslovaquia, Eslovenia, República Checa y Hungría y un tercero integrado por Letonia, Estonia y Lituania. Esta agrupación es fruto del gap en mortalidad que existe entre los países del oeste de la Unión Europea y los del este, siendo en estos últimos donde se muestran valores más desfavorables. La caracterización de estos grupos muestra que la esperanza de vida al nacer es el indicador de mortalidad que más discrimina entre los clusters obtenidos.[EN] Comparisons of longevity by country help policymakers and analysts to evaluate the amount of individuals and time periods, in which they get benefits from public programs like social security and health care. This research presents a method to group the European Union countries with similar mortality behavior. Mortality inequalities found in the groups of European Union countries are characterized by means of mortality indicators. It is concluded that there are differences in mortality between East and West European Union, with a clear disadvantage to the East. So three clusters are found. The first one consists of Germany, Austria, Belgium, Denmark, Spain, Finland, France, Netherlands, Ireland, Italy, Luxembourg, Portugal, United Kingdom and Sweden. The second one consists of Bulgaria, Poland, Slovakia, Slovenia, Czech Republic and Hungary. Latvia, Estonia and Lithuania make up the last cluster. The characterization of these clusters shows that life expectancy at birth is the mortality indicator that discriminates the most among the clusters obtained.Este trabajo ha sido financiado por un proyecto del Ministerio de Economía y Competitividad (MTM2013-45381-P)Esteban Chaves, L.; Debón Aucejo, AM.; Villa Juliá, MF. (2016). Comportamiento de la mortalidad en los países de la Unión Europea y caracterización según sus índices de mortalidad. Estadística española. 58(191):213-243. http://hdl.handle.net/10251/81422S2132435819

GRASP and path relinking for project scheduling under partially renewable resources

[EN] Recently, in the field of project scheduling problems the concept of partially renewable resources has been introduced. Theoretically, it is a generalization of both renewable and non-renewable resources. From an applied point of view, partially renewable resources allow us to model a large variety of situations that do not fit into classical models, but can be found in real problems in timetabling and labor scheduling. In this paper, we develop some preprocessing techniques and several heuristic algorithms for the problem. Preprocessing significantly reduces the dimension of the problems, therefore improving the efficiency of solution procedures. Heuristic algorithms based on GRASP and Path relinking are then developed and tested on existing test instances, obtaining excellent results.This work has been partially supported by the Spanish Ministry of Education and Science DPI2005-04796Alvarez-Valdes, R.; Crespo, E.; Tamarit, J.; Villa Juliá, MF. (2008). GRASP and path relinking for project scheduling under partially renewable resources. European Journal of Operational Research. 189(3):1153-1170. https://doi.org/10.1016/j.ejor.2006.06.073S11531170189

Models and algorithms for a yard crane scheduling problem in container ports

[EN] This paper addresses the scheduling of a yard crane in an automated container block, considering its rela-tionships with the other terminal subsystems. Containers coming into the block to be stored have release times, indicating the moment at which they arrive from ships or trucks. Containers being retrieved have due times, indicating when they will be required by other subsystems. The problem can be seen as a pickup routing problem and also as a one-machine scheduling problem. As a starting point, integer linear models were developed for both approaches. Then, to obtain good solutions for large instances, several heuristic algorithms, coupled with a local search, were proposed. An extensive computational study, based on a newly generated benchmark, shows the limits of the exact methods and the quality of the solutions obtained by the heuristics.The authors are partially supported by the Spanish Ministry of Science and Innovation under the project "OPTEP-Port Terminal Operations Optimization" (No. RTI2018-094940-B-I00), partially financed with FEDER funds, by the Spanish Ministry of Science and Innovation under the project "OPRES-Realistic Optimization in Problems in Public Healt"(No. PID2021-124975OB-I00), partially financed with FEDER funds and by the Agencia Valenciana de la Innovacio (AVI) under the project "ireves (innovacion en vehiculos de emergencia sanitaria): una herramienta inteligente de decision" (No. INNACC/2021/26) partially financed with FEDER funds (interested readers can visit http://ireves.upv.es). Some of the authors are supported by the Faculty of Business Administration and Man-agement at the Universitat Politecnica de Valencia. Special thanks are due to Gerardo Gabriel Minella from Instituto Tecnologico de Informatica.Vallada Regalado, E.; Belenguer, JM.; Villa Juliá, MF.; Alvarez-Valdes, R. (2023). Models and algorithms for a yard crane scheduling problem in container ports. European Journal of Operational Research. 309(2):910-924. https://doi.org/10.1016/j.ejor.2023.01.047910924309

Heuristic algorithms based on the isochron analysis for dynamic relocation of medical emergency vehicles

[EN] Among the wide range of medical services, prehospital health care is one of the most relevant, as it usually involves an emergency situation. The qualified medical team is dispatched to the scene of the incident as soon as possible. One of the most influential factors in response time depends on where the ambulances are stationed, however, when a medical vehicle is attending an emergency, it becomes unavailable for other calls. Increasing the ambulance fleet is a costly option that does not guarantee efficiency. An alternative solution is the relocation of available ambulances to increase the population covered by them. Obtaining the optimal solution in real time is not feasible for this problem. Therefore, this work addresses the problem of dynamic relocation of ambulances through the design and development of heuristic tools. The isochron overlap analysis defines possible scenarios that may occur when ambulances become unavailable for emergencies and determines the appropriate conditions to carry out the relocation of ambulances. Computational experiments are run using a benchmark of instances based on the characteristics of a real Emergency Medical Service. Based on the results of the study, we can conclude that the designed relocation algorithms perform better than if there was no relocation strategy.The authors are supported by Agència Valenciana de la Innovació (AVI), Spain under the project ireves (innovación en vehículos de emergencia sanitaria): una herramienta inteligente de decisión (No. INNACC/2021/26). This project has been partially financed with FEDER, Spain funds. Interested readers can visit http://ireves.upv.es. The authors are supported by the Spanish Ministry of Science and Innovation under the project ``OPRES-Realistic Optimization in Problems in Public Health¿¿(No. PID2021-124975OB-I00), partially financed with FEDER funds. Part of the authors are supported by the Faculty of Business Administration and Management at Universitat Politècnica de València, Spain and Yulia Karpova is supported under the project Programa de Ayudas de Investigación y Desarrollo (PAID-01-21) de la Universitat Politècnica de València. Special thanks to Servicio de Atención Sanitaria a Urgencias Emergencias (SASUE) and to Servicios de Emergencias Sanitarias (SES) of the Comunitat Valenciana, and Department of Coordination of Medical Transport for the information and data provided. All authors have contributed to all sections and tasks performed in this article.Karpova-Krylova, Y.; Villa Juliá, MF.; Vallada Regalado, E.; Vecina, MÁ. (2023). Heuristic algorithms based on the isochron analysis for dynamic relocation of medical emergency vehicles. Expert Systems with Applications. 212. https://doi.org/10.1016/j.eswa.2022.11877321