Joaquín Bautista-Valhondo

Universitat Politècnica de Catalunya | UPC · IOC - Institute of Industrial and Control Engineering

SINOPSIS ¿Es P igual a NP o es P distinto de NP? El dilema que acaba de leer admite la concesión o negación de cualquiera de sus dos premisas, y demostrar qué camino es el correcto está premiado con un millón de dólares por el Instituto Clay de Matemáticas desde el año 2000, siendo tal disyuntiva uno de los 7 Problemas del Milenio. La Teoría de la...

SINOPSIS: Escribía Aristóteles en La Política que el hombre es por naturaleza un animal social, a lo que podría añadirse que el hombre es por su cultura un animal cuantitativo, pues las cosas derivadas del echar cuentas nos son inherentes y nos distinguen de otros seres vivos. Las decisiones intuitivas (con o sin acierto) no son generalmente bien...

SINOPSIS: La vida cotidiana nos presenta numerosas situaciones en las que dos o más partes, con intereses distintos y a veces divergentes, compiten por posiciones, premios o recursos escasos. Cuando dichas partes tienen la posibilidad de ejecutar diversas acciones encaminadas a alcanzar sus respectivos objetivos, se producen de manera natural situa...

The paper assumes that, at the end of the operational period of a Spanish nuclear power plant, an Independent Spent Fuel Storage Installation will be used for long-term storage. Spent fuel assemblies are selected and transferred to casks for dry storage, with a series of imposed restrictions (e.g., limiting the thermal load). In this context, we pr...

This work is based on the management of fuel waste from Spanish nuclear power plants. It is planned to activate individualized temporary warehouses (ITW) when the saturation of the pool intended to hold spent nuclear fuel elements is reached while the facility is operated. At the end of this period, an ITW can be used as a short or long-term tempor...

This work seeks to evaluate the convenience of adapting mixed-model assembly lines to the Just in Time ideology adopted by Lean Manufacturing by means of application of Heijunka concept into production sequences. To do this two mixed integer linear programming models have been solved by the IBM-CPLEX solver on the set of 23 Nissan-9Eng.I instances....

A problem of sequences in production lines of mixed models is presented, transforming the production line into a blocking flowshop. The Heijunka concept is applied to the sequences, imposing compliance with the Quota property, with the purpose of adapting the workshop to the Just in Time ideology adopted by Lean Manufacturing. The proposed problem...

El mercado laboral actual se caracteriza por un aumento en la exigencia de los perfiles profesionales demandados. Concretamente, en el ámbito de la ingeniería, cada vez más, se requieren perfiles que reúnan, además de los conocimientos técnicos, habilidades personales, sociales y metodológicas. En este sentido, son muchos los estudios que demuestra...

Los proyectos han acompañado al ser humano desde las primeras civilizaciones, debido en parte a la preciosa curiosidad y bien orientada inquietud que (muchas veces) caracteriza a nuestra especie. Así que no es de extrañar que cada día tengamos noticias sobre logros científicos y técnicos, nuevos artefactos, construcción de grandes instalaciones, ro...

In this paper a problem of job sequences in a workshop is presented, taking into account non-unit demands for these and whose objective is to obtain manufacturing sequences satisfying the Quota property with a minimum total completion time for all the jobs \(\left( {C_{max} } \right)\). Two procedures are proposed to solve the problem: Mixed Intege...

Keywords: Metodologías de aprendizaje activo, Estrategias de aprendizaje cooperativo basado en problemas y proyectos, Desarrollo competencial

Palabras clave: Flujo regular, Heijunka, JIT, Propiedad Quota, Secuenciación

In this paper, a new problem of job sequences in a workshop is presented, taking into account non-unit demands for the jobs and whose objective is to minimize the total completion time for all the jobs (Cmax) satisfying a set of restrictions imposed on the problem to preserve the production mix. Two procedures are proposed to solve the new problem:...

El término Heijunka se asocia a la regularidad de la producción, siendo esta una propiedad deseable en todo plan de producción por facilitar la gestión de operaciones y propiciar la reducción de stocks. En este marco conceptual, se establecen tres propiedades deseables que deben cumplir, dentro de lo posible, los planes y las secuencias para ser co...

Two mathematical models are proposed in order to obtain assembly line configurations that guarantee a maximum productivity while the ergonomic risk of workstations is controlled and the available space for the line is respected. Both models, with different optimization approaches, are assessed through a daily demand plan linked with the Nissan powe...

This paper presents a mixed integer linear programming model (MILP) for optimizing the volunteers’ assignment to types of tasks required by the organizers of a sports event. The model takes into account a set of volunteers and their profiles, a set of required tasks, and a set of venues of the event. The main objective is to maximize the global apt...

RESUMEN: Se presenta en detalle siete soluciones óptimas para la instancia de datos Ascó#01_06 relacionada con la central nuclear Ascó-1 ubicada a 160 km de Barcelona. El procedimiento utilizado para hallar tales soluciones se despliega en dos fases. En la primera fase, se utiliza el modelo MILP-1 descrito en [2], cuyo objetivo es minimizar el cost...

This paper presents two mixed integer linear programming (MILP) models that extend two basic Flow Shop Scheduling problems: Fm/prmu/Cmax and Fm/block/Cmax. This extension incorporates the concept of an overall demand plan for types of jobs or products. After using an example to illustrate the new problems under study, we evaluated the new models an...

En la gestión de residuos de combustible de las centrales nucleares españolas, está previsto activar los almacenes temporales individualizados (ATI) cuando se alcanza la saturación de la piscina destinada a albergar elementos de combustible nuclear gastado durante el periodo de explotación de la instalación; al finalizar dicho periodo, un ATI puede...

En este trabajo aplicamos dos modelos de Programación lineal entera mixta, sobre problemas de taller de flujo regular con deman-da generalizada de tipos de trabajos, con el propósito de transformar una línea de modelos mixtos en un taller de flujo regular. Para ilustrar dicha aplicación, presentamos un caso de estudio basado en una línea de motores...

The car sequencing problem is a well established problem that models the conflicts arising from scheduling cars into an assembly line. However, the existing approaches to this problem do not consider non-regular or out-of-catalog vehicles, which are commonly manufactured in assembly lines. In this paper, we propose a new problem definition that dea...

The concept of partial demand uncertainty is introduced from the car sequencing problem (CSP) and incorporates special vehicle fleets in a demand plan. After establishing the working hypotheses with fleets, a mixed integer linear programming model, robust car sequencing problem (r-CSP), is proposed to satisfy the maximum number of CSP restrictions....

Changing conditions and variations in the demand are frequent in real industrial environments. Decision makers have to take into account this uncertainty and manage it properly. One clear example is the automotive industry where manufacturers have to assume an uncertain and heterogeneous demand. For instance, automotive manufacturers must adapt the...

Any sport event can count with volunteers to support the rest of participants (organizers, officials…). This group usually concentrates an important number of collaborators who work selflessly, but with heterogeneity of profiles. The organizational success of these events depends to a large extent on their efficiency in the assigned tasks. Here, it...

PROGRESS IN ARTIFICIAL INTELLIGENCE 7(4): 327–338. Abstract: This work examines a balancing problem wherein the objective is to minimize both the ergonomic risk dispersion between the set of workstations of a mixed-model assembly line and the risk level of the workstation with the greatest ergonomic factor. A greedy randomized adaptive search proce...

Resumen-Partiendo de los modelos TSALBP-ergo (Time and Space Assembly Line Balancing Problem with Ergonomic Risk), proponemos 9 métricas para medir la robustez de un equilibrado de línea según sus atributos temporales, espaciales y contingentes. La versión robusta de TSALBP-ergo considera diversos planes de demanda e incluye funciones que miden los...

We present a GRASP algorithm to solve a problem that involves the sequencing of mixed products in an assembly line. The objective of the problem is to obtain a manufacturing sequence of models that generates a minimum operational cost with a forced interruption of operations and that is regular in production. The implemented GRASP is compared with...

Resumen-Car sequencing problem (CSP) es un problema tradicional de satisfacción de restricciones que refleja los problemas que surgen cuando una serie de vehículos se introducen en una cadena de producción. Sin embargo no considera vehículos no regulares o fuera de catálogo, pese a que en plantas reales pueden llegar a representar entre el 10 % y e...

PROGRESS IN ARTIFICIAL INTELLIGENCE 7(3): 197-211. We present a GRASP algorithm to solve a problem that involves the sequencing of mixed products in an assembly line. The objective of the problem is to obtain a manufacturing sequence of models that generates a minimum work overload with a forced interruption of operations, which is regular in produ...

We present a variant of the approach to the assembly line balancing problems, with the aim of reducing the ergonomic risk for operators of mixed-model assembly lines (MILP-3). Specifically, the MILP-3 model is focused on minimizing the average range between ergonomic risk values of workstations. Using a case study from Nissan's plant in Barcelona,...

Appendices for “Managerial and industrial benefits of using robust multiobjective optimization for balancing an automotive assembly line”

One of the major issues in industrial environments is currently maximizing productivity while reducing manufacturing cost. This can be seen clearly reflected in mixed-model assembly lines based systems, where obtaining efficient manufacturing sequences is a key to be competitive in a dynamic and globalized market. However, this continuous cost redu...

In this research we present a model of Mixed Integer Linear Programming (MILP) to optimize the assignment of volunteers to the jobs required by an Organization destined to direct, coordinate and control the activities of a sporting event of large dimensions. The model takes into account the set of volunteers and their characteristics, as well as th...

We present a new mathematical model for the assembly line balancing problem with the objective of maximizing the line comfort to operators. Besides minimizing discrepancies between the ergonomic risks of workstations, balancing is subject to temporal and spatial conditions for the workstations. To evaluate the performance of the proposed model, we...

This paper introduces the synchronous manufacturing philosophy (douki seisan) devised by Nissan, and relates it to “Just in Sequence”, a common technique in current automotive industry. Literature is full of case studies, and the advantages and drawbacks of JIS have been reported. However, no attempt to model the necessary relations to make this sy...

Mixed-model assembly lines present two issues due to differences in processing times from product types; these issues are the work overload or unfinished work and the useless time or unproductive time. Within this context, we present, in this paper, a new mathematical model for the mixed-model sequencing problem. This model minimizes the costs by l...

El voluntariado es uno de los pilares de todo evento deportivo. En él se concentra un importante número de colaboradores que trabajan desinteresadamen-te, pero con una heterogeneidad de perfiles. El éxito organizativo de este tipo de eventos depende en gran parte de su eficiencia en las tareas asignadas. Se parte de una base de datos con perfiles d...

Presentamos modelos basados en la Programación Lineal Entera Mixta (MILP) para secuenciar productos mixtos con demanda general en contexto Flow Shop Scheduling Problem. Realizamos la explotación de los modelos con solver CPLEX limitando el tiempo de CPU y utilizando ejemplares de la literatura de mediana dimensión. Ante los resultados, concluimos q...

This work presents a new variant for the Time and Space Balancing Problem whose objective is balancing the ergonomic risk of operators of mixed-model assembly line. Specifically, the model is focused on minimizing the range between ergonomic risk values of workstations. In this way, not only the differences between levels of ergonomic risk of works...

This work addresses a balancing problem approach whose objective is to minimizing the ergonomic risk dispersion between the set of workstations of a mixed-model assembly line and the risk level of the workstation with the greatest hazard. A GRASP procedure is proposed to achieve these two challenges simultaneously. This new procedure is compared wi...

Presentamos un algoritmo GRASP para resolver un problema de secuenciación de productos mixtos en una línea de montaje. El objeto del problema es obtener una secuencia de fabricación de modelos que genere la mínima sobrecarga con interrupción forzada de las operaciones, que sea regular en producción y que el mix de producción mantenga la propiedad q...

PROGRESS IN ARTIFICIAL INTELLIGENCE 6(2): 159–169. A linear program-assisted hybrid algorithm (GRASP-LP) is presented to solve a mixed-model sequencing problem in an assembly line. The issue of the problem is to obtain manufacturing sequences of product models with the minimum work overload, allowing the free interruption of operations at workstati...

En este trabajo analizamos y comparamos las mejores secuencias para el conjunto de instancias Nissan-9Eng.I en un problema de secuenciación de modelos mixtos (MMSP) con mínima sobrecarga, máxima regularidad de fabricación, restricciones sobre la preservación del mix de producción y con interrupción forzada de operaciones. Las soluciones proceden de...

In this article, we propose a hybrid procedure based on bounded dynamic programming assisted by linear programming to solve the mixed-model sequencing problem with workload minimization with serial workstations, free interruption of the operations and with production mix restrictions. We performed a computational experiment with 23 instances relate...

In this work a new variant of the Mixed-Model Sequencing Problem with Work overload Minimization is formulated and evaluated. The new variant regularizes production, in addition to increase the amount of completed work through the workers’ activation at certain moments of their workday and to fulfill the conditions from collective agreements in ter...

DIRECCIÓN Y ORGANIZACIÓN 60 (Diciembre 2016): 57-65. http://www.revistadyo.com/index.php/dyo/issue/view/45 · ABSTRACT: Partiendo del Car Sequencing Problem (CSP), introducimos el concepto de demanda parcial incierta, incorporando Flotas de vehículos especiales en un plan de demanda. Tras establecer las hipótesis de trabajo con Flotas, proponemos u...

En este trabajo analizamos la regularidad de la producción de las mejores secuencias para el conjunto de instancias Nissan-9Ing.I, en el marco de un problema de secuenciación de modelos mixtos con mínima sobrecarga, restricciones sobre la preservación del mix de producción y con libre interrupción de operaciones. Las soluciones proceden de 3 fuente...

Partiendo del Car Sequencing Problem (CSP), introducimos el concepto demanda parcial incierta a través de la incorporación de Flotas de vehículos especiales en un plan de demanda. Tras resaltar las peculiaridades de una Flota y establecer las hipótesis de trabajo, proponemos un modelo de programación lineal entera mixta orientado a satisfacer el má...

This paper presents an action-research project aiming at improving the performance of “just-in-time, just-in-sequence” auto parts manufacturing and delivery in three tier-1 suppliers of the Nissan plant in Barcelona. This research was conducted at the Barcelona School of Engineering (ETSEIB) and promoted by the Nissan factory in Barcelona. In this...

Se presenta un algoritmo híbrido GRASP asistido por Programación Lineal (LP) para resolver un problema de secuenciación de productos mixtos en una línea de montaje. El objeto del problema es obtener una secuencia de fabricación de modelos que genere la mínima sobrecarga con libre interrupción de las operaciones, preservando el mix de producción. El...

This research examines an assembly line balancing problem and compares the linear programing with a Greedy Randomized Adaptive Search Procedure (GRASP). The problem focuses on minimizing the absolute average deviation for the ergonomic risk between the set of workstations of the line, considering a fixed cycle time and an available space per statio...

This research examines an assembly line balancing problem and compares the linear programing with a Greedy Randomized Adaptive Search Procedure (GRASP). The problem focuses on minimizing the absolute average deviation for the ergonomic risk between the set of workstations of the line, considering a fixed cycle time and an available space per statio...

This paper introduces the synchronous manufacturing philosophy (douki seisan) devised by Nissan, and relates it to " Just in Sequence " , a common technique in current automotive industry. Literature is full of case studies, and the advantages and drawbacks of JIS have been reported. However, no attempt to model the necessary relations to make this...

Mixed-model assembly lines present two issues due to differences in processing times from product types; these issues are the work overload or unfinished work and the useless time or unproductive time. Within this context, we present , in this paper, a new mathematical model for the mixed-model sequencing problem. This model minimizes the costs by...

We present a new mathematical model for the assembly line balancing problem with the objective of maximizing the line comfort to operators. Besides minimizing discrepancies between the ergonomic risks of workstations, balancing is subject to temporal and spatial conditions for the workstations. To evaluate the performance of the proposed model, we...

We aim at maximizing the comfort of operators in mixed-model assembly lines. To achieve this goal, we valuate two assembly line balancing models: the first that minimizes the maximum ergonomic risk and the second one that minimizes the average absolute deviations of ergonomic risk. Through a case study we ompare the results of the two models by two...

En este documento se recogen las mejores soluciones actuales de las instancias Nissan-9Ing.I para el problema de secuenciación de modelos mixtos con mínima sobrecarga, restricciones sobre el mix de producción y libre interrupción de operaciones. Dichas soluciones proceden de 3 fuentes: programación dinámica acotada mediante programación lineal, pro...

Assembly lines with mixed products present ergonomic risks that can affect productivity of workers and lines. Because of that, the line balancing must consider the risk of injury in regard with the set of tasks necessary to process a product unit, in addition to other managerial and technological attributes such as the workload or the space. Theref...

Siguiendo el objetivo de minimizar los costes por pérdida de producción y por tiempo desaprovechado, generados por las secuencias de una línea de montaje de modelos mixtos, se presentan dos modelos matemáticos equivalentes. Los modelos integran simultáneamente los conceptos de sobrecarga de trabajo y de tiempo inerte, además de contemplar la posibl...

A GRASP algorithm is presented for solving a sequencing problem in a mixed-model assembly line. The problem is focused on obtaining a manufacturing sequence that completes the greatest possible amount of required work and fulfils the production regularity property. The implemented GRASP algorithm is compared with other resolution procedures by mean...

Changes in demand when manufacturing different products require an optimization model that includes robustness in its definition and methods to deal with it. In this work we propose the r-TSALBP, a multiobjective model for assembly line balancing to search for the most robust line configurations when demand changes. The robust model definition cons...

Robust optimization tries to find flexible solutions when solving problems with uncertain scenarios and vague information. In this paper we present a multiobjective evolutionary algorithm to solve robust multiobjective ptimization problems. This algorithm is a novel adaptive method able to evolve separate populations of robust and non-robust soluti...

This research was conducted at the Barcelona School of Engineering (ETSEIB) and promoted by the Nissan factory in Barcelona. In this paper, first, the concept of synchronous manufacturing is explored. After several improvement ideas are spotted within the Nissan plant, the paper focuses on the suppliers. An intervention approach is proposed. Suppli...

En la Parte I del presente documento, establecimos las condiciones requeridas a la configuración de una línea para que pudiera ser clasificada como fuertemente-robusta, ante un conjunto de escenarios de la demanda y respetando las restricciones impuestas a los atributos de las estaciones de trabajo (temporales, espaciales y de contingencia). En dic...

Beginning with a variation of the sequencing problem in a mixed-products line (MMSP-W: Mixed-Model Sequencing Problem with Workload Minimization), we propose two new models that incorporate a set of working conditions in regard with human resources of workstations on the line. These conditions come from collective agreements and therefore must be r...

In this article, we propose a hybrid procedure based on bounded dynamic programming (BDP) assisted by linear programming to solve the mixed-model sequencing problem with workload minimization (MMSP-W) with serial workstations, free interruption of the operations and with production mix restrictions. We performed a computational experiment with 23 i...

A Greedy Randomized Adaptive Search Procedure (GRASP) is proposed to solve an extension of the assembly line balancing problem. The problem focuses on minimizing the maximum ergonomic risk of the assembly line when the space required by workstations, the cycle time, and the number of workstations of the line are given. To evaluate the GRASP procedu...

A Greedy Randomized Adaptive Search Procedure (GRASP) is proposed to solve an extension of the assembly line balancing problem. The problem focuses on minimizing the maximum ergonomic risk of the assembly line when the space required by workstations, the cycle time, and the number of workstations of the line are given. To evaluate the GRASP procedu...

Resumen. Se presenta un algoritmo GRASP para resolver un problema de secuenciación de productos en una línea de montaje de modelos mixtos. El objetivo del problema es obtener una secuencia de fabricación de productos con máximo trabajo total completado y cumpliendo la propiedad de regularidad en la producción. El algoritmo GRASP implementado se com...

Se establecen las condiciones requeridas a la configuración de una línea para que sea clasificada como fuertemente-robusta - en atributos temporales, espaciales y de riesgo ergonómico - ante un conjunto de escenarios de la demanda. Empleando los datos de un caso de estudio de la planta de motores de Nissan Motor Ibérica de Barcelona, se generan sol...

In this contribution, we propose an interactive multicriteria optimisation framework for the time and space assembly line balancing problem. The framework allows decision maker interaction by means of reference points to obtain the most interesting non-dominated solutions. The principal components of the framework are the g -dominance preference sc...

An action research experience in Douki-Seisan in cooperation with the Nissan Factory in Barcelona. Three suppliers are involved in the experience to improve the way they perform synchro deliveries of parts to Nissan. Supplier issues are analysed and a decision making tool is developed for a supplier.

This paper presents an action research experience in Douki-Seisan in cooperation with the Nissan Factory in Barcelona. Three suppliers are involved in the experience to improve the way they perform synchro deliveries of parts to Nissan. Supplier issues are analysed and a decision making tool is developed for a supplier.

A new mathematical model to solve the Mixed-Model Sequencing Problem with Work overload minimization is formulated. The model incorporates productive, social and legal aspects in order to move the theory problem closer to the actual industrial environments. Specifically, there are considered the variation of work pace of workers throughout the work...

In this paper we propose to incorporate some working conditions to the assembly lines. For this, used a mathematical model to solve the assembly line balancing problem whose objective is minimizing the ergonomic risk, imposing the limitation of the cycle time, number of workstations and the maximum linear area for each station. A study is presented...

In this paper we propose to incorporate some working conditions to the assembly lines. For this, used a mathematical model to solve the assembly line balancing problem whose objective is minimizing the ergonomic risk, imposing the limitation of the cycle time, number of workstations and the maximum linear area for each station. A study is presented...

En una línea simple de montaje mono-modelo, la eficiencia se define como el cociente entre el tiempo de proceso requerido para obtener una unidad de producto y el tiempo disponible para ello. Es obvio que esta limitada visión del concepto eficiencia -asociada únicamente a un atributo temporal y a un único tipo de producto- no es suficiente para med...

Partiendo de un problema de secuenciación en líneas de productos mixtos con minimización de la sobrecarga de trabajo (MMSP-W: Mixed-Model Sequencing Problem with Workload Minimisation), se proponen dos familias de modelos - MILP - que incorporan la activación modulada de los operadores a lo largo del tiempo con el propósito de incrementar la produc...

Partiendo de la familia de modelos TSALBP (Time and Space Assembly Line Balancing Problem), proponemos diversas funciones para medir la robustez de un equilibrado de línea atendiendo a sus atributos temporales y espaciales. La versión robusta de TSALBP considera un conjunto de escenarios de demanda y presenta funciones que miden el exceso de carga,...

Se proponen nuevos modelos que incorporan a un problema de secuenciación de productos mixtos (MMSP-W: Mixed Model Sequencing Problem with Workload Minimisation) la activación de los operadores a lo largo del tiempo para incrementar la productividad. Dicha activación se hace de dos formas: (1) Fijando el ritmo de trabajo y (2) limitando el ritmo de...

Changes in demand when manufacturing different products require an optimization model that includes robustness in its definition and methods to deal with it. In this work we propose the r-TSALBP, a multiobjective model for assembly line balancing to search for the most robust line configurations when demand changes. The robust model definition cons...

In this paper, it is presented an extension of the mixed-model sequencing problem with work overload minimization (MMSP-W) for production lines with serial workstations, parallel homogeneous processors, and variable operation processing times. This extension is intended to consider that the processing times of the operations can be prolonged or shr...

In this work it is presented a variant for the assembly line balancing that considers simultaneously production conditions and labour conditions. Specifically, a new mathematical model is formulated to solve the assembly line balancing problem. The objective of this model is minimising the maximum ergonomic risk, given a specific cycle time and a n...

It is presented an extension of the mixed-model sequencing problem that considers some working conditions agreed between companies and trade unions. In particular, it is formulated a mathematical model with saturation limits which an operator can have throughout his workday and with the possibility of increasing the work pace of the operators at ce...