http://hdl.handle.net/2117/537 Fri, 24 May 2013 19:38:28 GMT 2013-05-24T19:38:28Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/17720 Title: El curioso comportamiento del procedimiento de inserción de la heurística NEH en el problema Fm|block|Cmax Authors: Companys Pascual, Ramón; Ribas Vila, Immaculada Abstract: In this paper it is shown that, in some cases, the insertion pro-cedure of NEH does not improve the solution quality. This fact is observed spe-cially in the NEH-based heuristics that have been proposed in the literature of the blocking flow shop problem. As a result of this work, we recommend to evaluate the sequence before and after the insertion phase in order to retain the best one Wed, 13 Feb 2013 12:48:33 GMT http://hdl.handle.net/2117/17720 2013-02-13T12:48:33Z Companys Pascual, Ramón; Ribas Vila, Immaculada no In this paper it is shown that, in some cases, the insertion pro-cedure of NEH does not improve the solution quality. This fact is observed spe-cially in the NEH-based heuristics that have been proposed in the literature of the blocking flow shop problem. As a result of this work, we recommend to evaluate the sequence before and after the insertion phase in order to retain the best one http://hdl.handle.net/2117/17707 Title: Enhanced MILP model for the Accessibility Windows Assembly Line Balancing Problem (AWALBP) Authors: Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael Abstract: The Accessibility Windows Assembly Line Balancing Problem (AWALBP) arises in those assembly lines where, as opposed to traditional assembly lines, the dimensions of the workpieces are larger than the width of the workstations. This means that, at any cycle, a workstation cannot access to one whole workpiece, but only to a restricted portion of one or two consecutive workpieces [1]. In our problem the cycle decomposes into stationary stages separated between them by forward steps, according to a cyclic movement scheme. Wed, 13 Feb 2013 10:53:15 GMT http://hdl.handle.net/2117/17707 2013-02-13T10:53:15Z Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael no The Accessibility Windows Assembly Line Balancing Problem (AWALBP) arises in those assembly lines where, as opposed to traditional assembly lines, the dimensions of the workpieces are larger than the width of the workstations. This means that, at any cycle, a workstation cannot access to one whole workpiece, but only to a restricted portion of one or two consecutive workpieces [1]. In our problem the cycle decomposes into stationary stages separated between them by forward steps, according to a cyclic movement scheme. http://hdl.handle.net/2117/17706 Title: Exact and Heuristic Approaches for the Visibility Windows Assembly Line Balancing Problem (VWALBP) Authors: Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael Abstract: In this paper, we consider the problem that we name Visibility Windows Assembly Line Balancing Problem (VWALBP) [1], which arises in some actual automated production lines. In contrast to traditional assembly lines, the length of the workpieces may be larger than the visibility windows of the workstations, and because of this, only a limited portion of the unit can be reached from any station at any time. Wed, 13 Feb 2013 10:44:18 GMT http://hdl.handle.net/2117/17706 2013-02-13T10:44:18Z Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael no In this paper, we consider the problem that we name Visibility Windows Assembly Line Balancing Problem (VWALBP) [1], which arises in some actual automated production lines. In contrast to traditional assembly lines, the length of the workpieces may be larger than the visibility windows of the workstations, and because of this, only a limited portion of the unit can be reached from any station at any time. http://hdl.handle.net/2117/17704 Title: Heurísticas para el Visibility Windows Assembly Line Balancing Problem (VWALBP) Authors: Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael Abstract: En este trabajo se trata el problema conocido como problema de equilibrado de líneas de montaje con ventanas de visibilidad o Visibility Windows Assembly Line Balancing Problem (VWALBP), que ocurre en varios entornos de producción automatizados. En particular este problema surge, por ejemplo, en la producción de placas de circuito impreso (PCIs) en líneas pick&place. Este tipo de líneas consta de varias estaciones en paralelo que montan los componentes en posiciones predefinidas sobre la superficie de la placa. El montaje se realiza de modo cíclico (en cada ciclo se completa una pieza) y consiste en escoger (pick) un componente de un alimentador, trasladarlo hacia la placa, y colocarlo (place) en su posición correspondiente Wed, 13 Feb 2013 10:37:08 GMT http://hdl.handle.net/2117/17704 2013-02-13T10:37:08Z Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael no En este trabajo se trata el problema conocido como problema de equilibrado de líneas de montaje con ventanas de visibilidad o Visibility Windows Assembly Line Balancing Problem (VWALBP), que ocurre en varios entornos de producción automatizados. En particular este problema surge, por ejemplo, en la producción de placas de circuito impreso (PCIs) en líneas pick&place. Este tipo de líneas consta de varias estaciones en paralelo que montan los componentes en posiciones predefinidas sobre la superficie de la placa. El montaje se realiza de modo cíclico (en cada ciclo se completa una pieza) y consiste en escoger (pick) un componente de un alimentador, trasladarlo hacia la placa, y colocarlo (place) en su posición correspondiente http://hdl.handle.net/2117/17702 Title: Programación de la producción en máquinas en paralelo con lotes de transferencia: un caso de estudio. Authors: Calleja Sanz, Gema; Pastor Moreno, Rafael Wed, 13 Feb 2013 10:29:27 GMT http://hdl.handle.net/2117/17702 2013-02-13T10:29:27Z Calleja Sanz, Gema; Pastor Moreno, Rafael no http://hdl.handle.net/2117/17701 Title: Modelo de PLEM mejorado para el Accessibility Windows Assembly Line Balancing Problem (AWALBP) Authors: Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael Abstract: The Accessibility Windows Assembly Line Balancing Prob-lem (AWALBP) occurs in those assembly lines where the length of the workpiec-es is large relative to the width of the workstations. As a result, each workstation can only access to the limited portion of workpiece(s) that is inside its accessibil-ity window. In previous works we proposed a mixed-integer linear programming (MILP) model and a heuristic decomposition approach to solve AWALBP. Com-putational results revealed the size limits of the instances that could be solved. In this work, we provide an enhanced MILP model using reformulations and addi-tional bound contraints, which significantly improves the percentage of the in-stances optimally solved. Wed, 13 Feb 2013 10:21:22 GMT http://hdl.handle.net/2117/17701 2013-02-13T10:21:22Z Calleja Sanz, Gema; Corominas Subias, Albert; García Villoria, Alberto; Pastor Moreno, Rafael no The Accessibility Windows Assembly Line Balancing Prob-lem (AWALBP) occurs in those assembly lines where the length of the workpiec-es is large relative to the width of the workstations. As a result, each workstation can only access to the limited portion of workpiece(s) that is inside its accessibil-ity window. In previous works we proposed a mixed-integer linear programming (MILP) model and a heuristic decomposition approach to solve AWALBP. Com-putational results revealed the size limits of the instances that could be solved. In this work, we provide an enhanced MILP model using reformulations and addi-tional bound contraints, which significantly improves the percentage of the in-stances optimally solved. http://hdl.handle.net/2117/17632 Title: Heurística basada en PLEM para resolver proyectos de electrificación rural Authors: Triadó-Aymerich, Joan; Ferrer Martí, Laia; García Villoria, Alberto; Pastor Moreno, Rafael Abstract: En la literatura se ha propuesto un modelo matemático para diseños de electrificación rural con generación eólica y solar en el que tiene que decidirse la localización de cada uno de los componentes de generación y distribución de energía eléctrica. Cuando la cantidad de viviendas a electrificar excede de un cierto número, la resolución del modelo matemático requiere un tiempo computacional que puede ser inviable en la práctica. En este artículo se presenta un método heurístico basado en programación lineal entera y mixta para la resolución de ejemplares con gran número de viviendas. Para ello proponemos un proceso en dos etapas. En la primera etapa se resuelve el modelo con algunas de las variables relajadas. En la segunda etapa se fijan algunas variables enteras resultado de la etapa 1 y se resuelve el modelo sin relajar. En este artículo se presenta una extensa experiencia computacional para evaluar la heurística propuesta y se constata una mejora de las soluciones obtenidas. Mon, 11 Feb 2013 13:42:24 GMT http://hdl.handle.net/2117/17632 2013-02-11T13:42:24Z Triadó-Aymerich, Joan; Ferrer Martí, Laia; García Villoria, Alberto; Pastor Moreno, Rafael no En la literatura se ha propuesto un modelo matemático para diseños de electrificación rural con generación eólica y solar en el que tiene que decidirse la localización de cada uno de los componentes de generación y distribución de energía eléctrica. Cuando la cantidad de viviendas a electrificar excede de un cierto número, la resolución del modelo matemático requiere un tiempo computacional que puede ser inviable en la práctica. En este artículo se presenta un método heurístico basado en programación lineal entera y mixta para la resolución de ejemplares con gran número de viviendas. Para ello proponemos un proceso en dos etapas. En la primera etapa se resuelve el modelo con algunas de las variables relajadas. En la segunda etapa se fijan algunas variables enteras resultado de la etapa 1 y se resuelve el modelo sin relajar. En este artículo se presenta una extensa experiencia computacional para evaluar la heurística propuesta y se constata una mejora de las soluciones obtenidas. http://hdl.handle.net/2117/17630 Title: Heurística basada en un indicador de demanda y potencial para diseñar sistemas de electrificación Authors: Ranaboldo, Matteo; Ferrer Martí, Laia; García Villoria, Alberto; Pastor Moreno, Rafael Mon, 11 Feb 2013 12:58:23 GMT http://hdl.handle.net/2117/17630 2013-02-11T12:58:23Z Ranaboldo, Matteo; Ferrer Martí, Laia; García Villoria, Alberto; Pastor Moreno, Rafael no http://hdl.handle.net/2117/17624 Title: Diseño de sistemas autónomos de electrificación rural con consideraciones técnicas y sociales Authors: Domenech, Bruno; Ferrer Martí, Laia; Pastor Moreno, Rafael Abstract: Los sistemas de electrificación basados en el uso de energía eólica y solar, y que combinan la distribución en microrred e individual, son adecuados para electrificar comunidades aisladas de forma autónoma. Para diseñarlos existen modelos que consideran restricciones técnicas y económicas. Entre las diferentes soluciones posibles, algunas pueden tener problemas en la continuidad del suministro o resultan difíciles de gestionar. Este trabajo analiza estos condicionantes y propone mejoras a incorporar en los modelos, que se validan mediante la aplicación a la comunidad de Alto Perú (Cajamarca, Perú). Se demuestra que las mejoras propuestas permiten obtener unas soluciones con unos beneficios sociales que compensan ampliamente los pequeños incrementos de coste. Mon, 11 Feb 2013 11:54:34 GMT http://hdl.handle.net/2117/17624 2013-02-11T11:54:34Z Domenech, Bruno; Ferrer Martí, Laia; Pastor Moreno, Rafael no Los sistemas de electrificación basados en el uso de energía eólica y solar, y que combinan la distribución en microrred e individual, son adecuados para electrificar comunidades aisladas de forma autónoma. Para diseñarlos existen modelos que consideran restricciones técnicas y económicas. Entre las diferentes soluciones posibles, algunas pueden tener problemas en la continuidad del suministro o resultan difíciles de gestionar. Este trabajo analiza estos condicionantes y propone mejoras a incorporar en los modelos, que se validan mediante la aplicación a la comunidad de Alto Perú (Cajamarca, Perú). Se demuestra que las mejoras propuestas permiten obtener unas soluciones con unos beneficios sociales que compensan ampliamente los pequeños incrementos de coste. http://hdl.handle.net/2117/17619 Title: Un modelo de ubicación de microaerogeneradores para el diseño de proyectos de electrificación rural con energía eólica Authors: Ferrer Martí, Laia; Pastor Moreno, Rafael; Capó, Gregori Miquel Mon, 11 Feb 2013 10:25:25 GMT http://hdl.handle.net/2117/17619 2013-02-11T10:25:25Z Ferrer Martí, Laia; Pastor Moreno, Rafael; Capó, Gregori Miquel no http://hdl.handle.net/2117/17579 Title: Combinando randomización sesgada y búsqueda local iterativa para resolver problemas de flow-shop Authors: Lourenço, Helena R.; Mateo Doll, Manuel; Grasas, Alex; Agustín Martín, Alba; Juan Pérez, Angel Alejandro Abstract: A la hora de poder aplicar algoritmos te oricos a casos reales, no solo resulta conveniente que el algoritmo sea e ciente sino tambi en que sea lo m as comprensible posible y que no requiera de comple- jos procesos de parametrizaci on. Siguiendo esta l ogi- ca, proponemos aqu un algoritmo h brido que reune las caracter sticas anteriores para resolver el proble- ma del Flow-Shop (FSP). El algoritmo, que no re- quire de parametrizaci on alguna, combina estrategias de randomizaci on con una B usqueda Local Iterativa (ILS), logrando ser competitivo con otros conocidos algoritmos que se encuentran entre los m as simples y e cientes para el FSP. Nuestro enfoque de ne (1) un nuevo operador para el proceso de perturbaci on ILS, (2) un nuevo criterio de aceptaci on basado en reglas simples y transparentes, y (3) un proceso de random- izaci on sesgada de la soluci on inicial. Los resultados preliminares obtenidos con las instancias de Taillard permiten concluir que la soluci on propuesta puede ser una excelente alternativa en aplicaciones reales Tue, 05 Feb 2013 12:27:03 GMT http://hdl.handle.net/2117/17579 2013-02-05T12:27:03Z Lourenço, Helena R.; Mateo Doll, Manuel; Grasas, Alex; Agustín Martín, Alba; Juan Pérez, Angel Alejandro no A la hora de poder aplicar algoritmos te oricos a casos reales, no solo resulta conveniente que el algoritmo sea e ciente sino tambi en que sea lo m as comprensible posible y que no requiera de comple- jos procesos de parametrizaci on. Siguiendo esta l ogi- ca, proponemos aqu un algoritmo h brido que reune las caracter sticas anteriores para resolver el proble- ma del Flow-Shop (FSP). El algoritmo, que no re- quire de parametrizaci on alguna, combina estrategias de randomizaci on con una B usqueda Local Iterativa (ILS), logrando ser competitivo con otros conocidos algoritmos que se encuentran entre los m as simples y e cientes para el FSP. Nuestro enfoque de ne (1) un nuevo operador para el proceso de perturbaci on ILS, (2) un nuevo criterio de aceptaci on basado en reglas simples y transparentes, y (3) un proceso de random- izaci on sesgada de la soluci on inicial. Los resultados preliminares obtenidos con las instancias de Taillard permiten concluir que la soluci on propuesta puede ser una excelente alternativa en aplicaciones reales http://hdl.handle.net/2117/17532 Title: A simulation-based approach for solving the flowshop problem Authors: Juan Pérez, Angel Alejandro; Ruíz, Rubén; Lourenço, Helena R.; Mateo Doll, Manuel; Ionescu, Dragos Abstract: A simulation-based algorithm for the Permutation Flowshop Sequencing Problem (PFSP) is presented. The algorithm uses Monte Carlo Simulation and a discrete version of the triangular distribution to incorporate a randomness criterion in the classical Nawaz, Enscore, and Ham (NEH) heuristic and starts an iterative process in order to obtain a set of alternative solutions to the PFSP. Thus, a random but biased lo We can then consider several properties per solution other than the makespan, such as balanced idle times among machines, number of completed jobs at a given target time, etc. This allows the decision-maker to consider multiple solution characteristics apart from those defined by the aprioristic objective function. Therefore, our methodology provides flexibility during the sequence selection process, which may help to improve the scheduling process. Several tests have been performed to discuss the effectiveness of this approach. The results obtained so far are promising enough to encourage further developments and improvements on the algorithm and its applications in real-life scenarios. In particular, Multi-Agent Simulation is proposed as a promising technique to be explored in future works. Wed, 30 Jan 2013 13:34:26 GMT http://hdl.handle.net/2117/17532 2013-01-30T13:34:26Z Juan Pérez, Angel Alejandro; Ruíz, Rubén; Lourenço, Helena R.; Mateo Doll, Manuel; Ionescu, Dragos no A simulation-based algorithm for the Permutation Flowshop Sequencing Problem (PFSP) is presented. The algorithm uses Monte Carlo Simulation and a discrete version of the triangular distribution to incorporate a randomness criterion in the classical Nawaz, Enscore, and Ham (NEH) heuristic and starts an iterative process in order to obtain a set of alternative solutions to the PFSP. Thus, a random but biased lo We can then consider several properties per solution other than the makespan, such as balanced idle times among machines, number of completed jobs at a given target time, etc. This allows the decision-maker to consider multiple solution characteristics apart from those defined by the aprioristic objective function. Therefore, our methodology provides flexibility during the sequence selection process, which may help to improve the scheduling process. Several tests have been performed to discuss the effectiveness of this approach. The results obtained so far are promising enough to encourage further developments and improvements on the algorithm and its applications in real-life scenarios. In particular, Multi-Agent Simulation is proposed as a promising technique to be explored in future works. http://hdl.handle.net/2117/17196 Title: La cultura organizativa y la percepción de igualdad de oportunidades de género Authors: Tura Solvas, Marta; Martínez Costa, Carme Mon, 07 Jan 2013 12:21:14 GMT http://hdl.handle.net/2117/17196 2013-01-07T12:21:14Z Tura Solvas, Marta; Martínez Costa, Carme no http://hdl.handle.net/2117/17087 Title: An algorithm for a biobjective parallel machine problem with eligibility and release and delivery times Authors: Mateo Doll, Manuel; Teghem, Jacques Abstract: The scheduling of parallel machines is a well-known problem in many companies. Nevertheless, not always all the jobs can be manufactured in any machine and the eligibility appears. Based on a real-life situation, we present a company which has three different sets of machines, called as high-level, medium-level and low-level respectively. Besides, there are release times and delivery times related to the respective previous operations and following operations to the main process to be carried in the parallel machines. A set of n jobs to be scheduled on these m parallel machines are also distributed among levels. One job from a level can be manufactured in a machine of the same or higher level. Initially all the jobs are processed on the machines of high level. But a penalty appears when a job is manufactured in a machine different of this initial level. The proposed algorithm solves the problem with two criteria: the minimization of the completion time or makespan, Cmax, and the minimization of the total penalty. The objective is to determine or to approximate the Pareto front. Several alternatives are presented according to different rules to move a job from one machine to another and compared through numerical experiments. Description: Keywords: parallel machines, eligibility, release times, delivery times, Pareto front. Mon, 10 Dec 2012 12:40:55 GMT http://hdl.handle.net/2117/17087 2012-12-10T12:40:55Z Mateo Doll, Manuel; Teghem, Jacques no The scheduling of parallel machines is a well-known problem in many companies. Nevertheless, not always all the jobs can be manufactured in any machine and the eligibility appears. Based on a real-life situation, we present a company which has three different sets of machines, called as high-level, medium-level and low-level respectively. Besides, there are release times and delivery times related to the respective previous operations and following operations to the main process to be carried in the parallel machines. A set of n jobs to be scheduled on these m parallel machines are also distributed among levels. One job from a level can be manufactured in a machine of the same or higher level. Initially all the jobs are processed on the machines of high level. But a penalty appears when a job is manufactured in a machine different of this initial level. The proposed algorithm solves the problem with two criteria: the minimization of the completion time or makespan, Cmax, and the minimization of the total penalty. The objective is to determine or to approximate the Pareto front. Several alternatives are presented according to different rules to move a job from one machine to another and compared through numerical experiments. http://hdl.handle.net/2117/17021 Title: Strategic capacity planning in KIOs: a classification scheme Authors: Martínez Costa, Carme; Lusa García, Amaia; Mas Machuca, Marta; Torre Martínez, María del Rocío de la; Mateo Doll, Manuel Abstract: This paper introduces the Strategic Capacity Planning problem in knowledge intensive organizations (KIOs) and proposes a classification scheme based on different characteristics such as the organization structure, the workforce characteristics, the capacity requirements, the capacity decisions or the evaluation criteria, among others. The classification, which gives rise to a high number of variants, is the first step towards a general solving methodology design and the developing of ad hoc solving procedures Mon, 26 Nov 2012 10:58:26 GMT http://hdl.handle.net/2117/17021 2012-11-26T10:58:26Z Martínez Costa, Carme; Lusa García, Amaia; Mas Machuca, Marta; Torre Martínez, María del Rocío de la; Mateo Doll, Manuel no This paper introduces the Strategic Capacity Planning problem in knowledge intensive organizations (KIOs) and proposes a classification scheme based on different characteristics such as the organization structure, the workforce characteristics, the capacity requirements, the capacity decisions or the evaluation criteria, among others. The classification, which gives rise to a high number of variants, is the first step towards a general solving methodology design and the developing of ad hoc solving procedures