The multi-objective assembly line worker integration and balancing problem of type-2

[EN] The consideration of worker heterogeneity in assembly lines has received a fair amount of attention in the literature in the past decade. Most of this exploration uses as motivation the example of assembly lines in sheltered work centers for the disabled. Only recently has the community started looking at the situation faced in assembly lines in the general industrial park, when in the presence of worker heterogeneity. This step raises a number of questions around the best way to incorporate heterogeneous workers in the line, maximizing their integration while maintaining productivity levels. In this paper we propose the use of Miltenburg's regularity criterion and cycle time as metrics for integration of workers and productivity, respectively. We then define, model and develop heuristics for a line balancing problem with these two goals. Results obtained through an extensive set of computational experiments indicate that a good planning can obtain trade-off solutions that perform well in both objectives.This research was supported by CAPES -Brazil and MEC-Spain (coordinated project CAPES DGU 258-12/PHB2011-0012-PC ) and by FAPESP -Brazil (grant number: 2010/19983-6 ).Moreira, MC.; Pastor, R.; Costa, A.; Miralles Insa, CJ. (2017). The multi-objective assembly line worker integration and balancing problem of type-2. Computers & Operations Research. 82:114-125. https://doi.org/10.1016/j.cor.2017.01.003S1141258

Optimization of manpower allocation by considering customer relationship management criteria and uncertainty conditions in car dealerships

Purpose A mathematical mixed integer model was used in this research in order to optimize manpower allocation in car industry. The objective function of proposed model subjected to minimization of the maximum waiting time for customers in service queue and limitations included manpower allocation and time calculation for each service in each center. Methodology: Therefore, mathematical optimization methods were employed in this research. To solve the problem at small dimensions, BARON solver was used through GAMS software. Metaheuristic algorithms were used to solve the large dimensions of problem due to NP-hard nature of allocation problem. However, these algorithms have been designed based on the natural elements; hence, a stochastic procedure is applied to generate initial responses and to improve the process to obtained the final response. Therefore, proper comparisons should be done to make sure of accurate performance of such procedure. To this end, three metaheuristic algorithms of Genetic, Harmony Search and Gray Wolf were used to solve the final problem. Findings: According to the obtained computational results, gray wolf algorithm had the highest performance efficiency compared to other algorithms so it is more practical in solving the real numerical samples. Originality/Value: The objective function of proposed model subjected to minimization of the maximum waiting time for customers in service queue and limitations included manpower allocation and time calculation for each service in each center. We used three metaheuristic algorithms, Genetic, Harmony Search and Gray Wolf, to solve the final problem

Balanceo de líneas de producción en la industria farmacéutica mediante Programación por metas

Introduction: In a production Line it’s important that the stations’ cycle times are balanced and that they are low since this allows to reduce the work in process. However, doing this leads to an increase in the stations’ number, that is not favorable because it raises the costs associated with the stations, therefore it is necessary to define strategies that allow achieving a balance between these requirements. Objective: In this article we propose the formulation of a model for the line balancing, using the technique of multi-objective goal programming, applied to the pharmaceutical industry in order to minimize the stations’ number, minimize cycle time and inventory in process. Methodology: Goal programming is used to address a line balance model, which considers at the same time the assignment of multiple stations to one operation and the assignment of multiple operations to one station. Results: A significant decrease in cycle time and idle time at minimum costs is achieved, and a comparison between the deterministic and stochastic models is presented. Conclusions: Through this implementation of the LINGO model, the compliance of the proposed restrictions, the precedence of operations and the proper functioning of the model were validated through the optimal solutions obtained. The simulation is a tool that illustrates the complexity of the operations of the production system, which require, as in our case, more realistic modeling to understand the behavior of the process and evaluate different strategies.Introducción: En una línea de fabricación es muy importante que los tiempos de ciclo de las diferentes estaciones estén balanceados y que sean bajos, ya que esto permite disminuir los inventarios de producto en proceso, sin embargo, hacer esto conlleva a aumentar el número de estaciones, lo que no es favorable ya que eleva los costos fijos asociados a las estaciones, en tal sentido es necesario definir estrategias que permitan lograr un equilibrio entre estos requerimientos. Objetivo: En este artículo se propone la formulación de un modelo para el balanceo de línea, utilizando la técnica de programación multiobjetivo por metas, aplicada a la industria farmacéutica con el fin de minimizar el número de estaciones, minimizar el tiempo de ciclo y el inventario en proceso. Metodología: Se emplea la programación por metas para abordar un modelo de balance de línea, que considera al mismo tiempo la asignación de múltiples estaciones una operación y la asignación de múltiples operaciones a una estación. Resultados: Se logra una reducción significativa del tiempo ciclo y del tiempo ocioso a costos mínimos, además se presenta una comparación entre el modelo determinístico y estocástico. Conclusiones: A través de esta implementación del modelo en LINGO, se validó el cumplimiento de las restricciones planteadas, la precedencia de las operaciones y el buen funcionamiento del modelo mediante las soluciones óptimas obtenidas. La simulación, es una herramienta que permite ilustrar la complejidad de las operaciones del sistema de producción, las cuales requieren como en nuestro caso de una modelación más ajustada a la realidad para comprender el comportamiento del proceso y evaluar diferentes estrategia

Production line balancing in the pharmaceutical industry using Goal Programming

Introducción−En una línea de fabricación es muy impor-tante que los tiempos de ciclo de las diferentes estaciones estén balanceados y que sean bajos, ya que esto permite disminuir los inventarios de producto en proceso, sin em-bargo, hacer esto conlleva a aumentar el número de esta-ciones, lo que no es favorable ya que eleva los costos fijos asociados a las estaciones, en tal sentido es necesario definir estrategias que permitan lograr un equilibrio entre estos requerimientos.Objetivo− En este artículo se propone la formulación de un modelo para el balanceo de línea, utilizando la técnica de programación multi-objetivo por metas, aplicada a la industria farmacéutica con el fin de minimizar el número de estaciones, minimizar el tiempo de ciclo y el inventario en proceso.Metodología− Se emplea la programación por metas para abordar un modelo de balance de línea, que considera al mis-mo tiempo la asignación de múltiples estaciones una opera-ción y la asignación de múltiples operaciones a una estación. Resultados− Se logra una reducción significativa del tiem-po ciclo y del tiempo ocioso a costos mínimos, además se presenta una comparación entre el modelo determinístico y estocástico.Conclusiones−A través de esta implementación del modelo en LINGO, se validó el cumplimiento de las restricciones planteadas, la precedencia de las operaciones y el buen funcionamiento del modelo mediante las soluciones óptimas obtenidas. La simulación, es una herramienta que permite ilustrar la complejidad de las operaciones del sistema de producción, las cuales requieren como en nuestro caso de una modelación más ajustada a la realidad para compren-der el comportamiento del proceso y evaluar diferentes estrategias.Introduction−In a production Line it’s important that the stations’ cycle times are balanced and that they are low since this allows to reduce the work in process. However, doing this leads to an increase in the stations’ number, that is not favorable because it raises the costs associated with the stations, therefore it is necessary to define strategies that allow achieving a balance be-tween these requirements.Objective−In this article we propose the formulation of a model for the line balancing, using the technique of multi-objective goal programming, applied to the pharmaceutical industry in order to minimize the stations’ number, minimize cycle time and inventory in process.Methodology−Goal programming is used to address a line balance model, which considers at the same time the assignment of multiple stations to one op-eration and the assignment of multiple operations to one station.Results−A significant decrease in cycle time and idle time at minimum costs is achieved, and a comparison between the deterministic and stochastic models is presented.Conclusions−Through this implementation of the LINGO model, the compliance of the proposed restric-tions, the precedence of operations and the proper func-tioning of the model were validated through the optimal solutions obtained. The simulation is a tool that illus-trates the complexity of the operations of the production system, which require, as in our case, a more realistic modeling to understand the behavior of the process and evaluate different strategies

Multi-job production systems: definition, problems, and product-mix performance portrait of serial lines

This paper pursues two goals: (a) Define a class of widely used in practice flexible manufacturing systems, referred to as Multi-Job Production (MJP) and formulate industrially motivated problems related to their performance. (b) Provide initial results concerning some of these problems pertaining to analysis of the throughput and bottlenecks of MJP serial lines as functions of the product-mix. In MJP systems, all job-types are processed by the same sequence of manufacturing operations, but with different processing time at some or all machines. To analyse MJP with unreliable machines, we introduce the work-based model of production systems, which is insensitive to whether single- or multi-job manufacturing takes place. Based on this model, we investigate the performance of MJP lines as a function of the product-mix. We show, in particular, that for the so-called conflicting jobs there exists a range of product-mixes, wherein the throughput of MJP is larger than that of any constituent job-type manufactured in a single-job regime. To characterise the global behaviour of MJP lines, we introduce the Product-Mix Performance Portrait, which represents the system properties for all product-mixes and which can be used for operations management. Finally, we report the results of an application at an automotive assembly plant

An integrated approach of artificial neural networks and system dynamics for estimating product completion time in a semiautomatic production

The determination of completion time to produce a new product is one of the most important indicators for manufacturers in delivering goods to customers. Failure to fulfil delivery on-time or known as tardiness contributes to a high cost of air shipment and production line down at other entities within the supply chain. The uncertainty of completion time has created a big problem for manufacturers of audio speakers which involved semiautomatic production lines. Therefore, the main objective of this research is to develop an integrated model that enhances the artificial neural networks (ANN) and system dynamics (SD) methods in estimating completion time focusing on the cycle time. Three ANN models based on multilayer perceptron (MLP) were developed with different network architectures to estimate cycle time. Furthermore, a proposed momentum rate equation was formulated for each model to improve learning process, where the 3-2-1 network emerged as the best network with the smallest mean square error. Subsequently, the estimated cycle time of the 3-2-1 network was simulated through the development of an SD model to evaluate the performance of completion time in terms of product quantity, manpower fatigue and production workload scores. The success of the proposed integrated ANNSD model also relied on a proposed coefficient correlation of causal loop diagram (CLD) to identify the most influential factor of completion time. As a result, the proposed integrated ANNSD model provided a beneficial guide to the company in determining the most influential factor on completion time so that the time to complete a new audio product can be estimated accurately. Consequently, product delivery was smooth for on-time shipment while successfully fulfilling customers’ demand

A Framework for Capacity and Operations Planning in Services Organizations Employing Workers with Intellectual Disabilities

[EN] This paper presents an integrated framework for capacity and operations planning in Spanish sheltered employment centers (SECs). Employment provides socio-economic opportunities for people with disability. Well functioning SECs that provide opportunities for people with and without disability to work alongside each other are an important component of Spain's current labor market. To be economically sustainable, SECs need to satisfy their clients expectations in terms of price, flexibility and performance, whilst taking into account and strengthening the diverse skills and abilities of their workforce like specific learning and forgetting processes. The SEC studied herein, a non-for-profit organization whose mission is to create employment for people with disabilities its workforce is deployed directly on clients' premises. Efficient management across this multi-site environment, whilst supporting the diverse employment needs of its staff, is of paramount importance. This paper contributes an integrated framework to support SEC capacity and operations planning, which prioritizes the explicit training needs of workers with disability at all levels (strategic, tactical, and operational) as a lever for achieving the organization's goals.García Sabater, JP.; Maheut, J.; Ruiz, A.; García Sabater, JJ. (2020). A Framework for Capacity and Operations Planning in Services Organizations Employing Workers with Intellectual Disabilities. Sustainability. 12(22):1-17. https://doi.org/10.3390/su12229713S1171222Fundación Espurnahttps://www.espurna.org/Convention on the Rights of Persons with Disabilities (A/RES/61/106)—Resolution adopted by the General Assembly on 13 December 2006https://www.un.org/en/development/desa/population/migration/generalassembly/docs/globalcompact/A_RES_61_106.pdfJarhag, S., Nilsson, G., & Werning, M. (2009). Disabled Persons and the Labor Market in Sweden. Social Work in Public Health, 24(3), 255-272. doi:10.1080/19371910802595315Mark, B. G., Hofmayer, S., Rauch, E., & Matt, D. T. (2019). Inclusion of Workers with Disabilities in Production 4.0: Legal Foundations in Europe and Potentials Through Worker Assistance Systems. Sustainability, 11(21), 5978. doi:10.3390/su11215978Santos, P. J. de los, & Costa, R. S. (2015). Workers with disabilities in sheltered employment centres: a training needs analysis. International Journal of Inclusive Education, 20(7), 756-769. doi:10.1080/13603116.2015.1111446Miralles, C., Marin-Garcia, J. A., Ferrus, G., & Costa, A. M. (2010). Operations research/management science tools for integrating people with disabilities into employment. A study on Valencia’s Sheltered Work Centres for Disabled. International Transactions in Operational Research, 17(4), 457-473. doi:10.1111/j.1475-3995.2009.00727.xChaves-Avila, R., & Savall-Morera, T. (2019). The Social Economy in a Context of Austerity Policies: The Tension Between Political Discourse and Implemented Policies in Spain. VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations, 30(3), 487-498. doi:10.1007/s11266-018-00075-3López-Penabad, M.-C., Maside-Sanfiz, J. M., Torrelles Manent, J., & Iglesias-Casal, A. (2020). Application of the DEA Double Bootstrap to Analyze Efficiency in Galician Sheltered Workshops. Sustainability, 12(16), 6625. doi:10.3390/su12166625Galeano Revert, A., García-Sabater, J. P., & Miralles Insa, C. (2018). Triple Bottom-line Business Model. Case study on the organic food retailing. WPOM-Working Papers on Operations Management, 9(1), 30. doi:10.4995/wpom.v9i1.9131Chi, C.-F., Dewi, R. S., Jang, Y., & Liu, H.-L. (2018). Workplace accommodation for workers with intellectual or psychiatric disabilities. International Journal of Industrial Ergonomics, 68, 1-7. doi:10.1016/j.ergon.2018.06.001Ellinger, A. E., Naidoo, J., Ellinger, A. D., Filips, K., & Herrin, G. D. (2020). Applying blue ocean strategy to hire and assimilate workers with disabilities into distribution centers. Business Horizons, 63(3), 339-350. doi:10.1016/j.bushor.2020.01.009Lindsay, S., Cagliostro, E., Albarico, M., Mortaji, N., & Karon, L. (2018). A Systematic Review of the Benefits of Hiring People with Disabilities. Journal of Occupational Rehabilitation, 28(4), 634-655. doi:10.1007/s10926-018-9756-zBitencourt, R. S., & de M. Guimarães, L. B. (2012). Inclusion of people with disabilities in the production system of a footwear industry. Work, 41, 4767-4774. doi:10.3233/wor-2012-0027-4767Hübner, A. H., Kuhn, H., & Sternbeck, M. G. (2013). Demand and supply chain planning in grocery retail: an operations planning framework. International Journal of Retail & Distribution Management, 41(7), 512-530. doi:10.1108/ijrdm-05-2013-0104Tuomikangas, N., & Kaipia, R. (2014). A coordination framework for sales and operations planning (S&OP): Synthesis from the literature. International Journal of Production Economics, 154, 243-262. doi:10.1016/j.ijpe.2014.04.026Li, Y., Chen, J., & Cai, X. (2007). An integrated staff-sizing approach considering feasibility of scheduling decision. Annals of Operations Research, 155(1), 361-390. doi:10.1007/s10479-007-0215-zZeng, L., Zhao, M., & Liu, Y. (2017). Airport ground workforce planning with hierarchical skills: a new formulation and branch-and-price approach. Annals of Operations Research, 275(1), 245-258. doi:10.1007/s10479-017-2624-yLlort, N., Lusa, A., Martínez-Costa, C., & Mateo, M. (2018). A decision support system and a mathematical model for strategic workforce planning in consultancies. Flexible Services and Manufacturing Journal, 31(2), 497-523. doi:10.1007/s10696-018-9321-2Van den Bergh, J., Beliën, J., De Bruecker, P., Demeulemeester, E., & De Boeck, L. (2013). Personnel scheduling: A literature review. European Journal of Operational Research, 226(3), 367-385. doi:10.1016/j.ejor.2012.11.029Henderson, J. C., Krajewski, L. J., & Showalter, M. J. (1982). An integrated approach for manpower planning in the service sector. Omega, 10(1), 61-73. doi:10.1016/0305-0483(82)90086-xKomarudin, De Feyter, T., Guerry, M.-A., & Vanden Berghe, G. (2020). The extended roster quality staffing problem: addressing roster quality variation within a staffing planning period. Journal of Scheduling, 23(2), 253-264. doi:10.1007/s10951-020-00654-7Das, D., & Yadav, C. (2020). A framework of hiring strategy for manpower hiring in a hyper-local food delivery organization. Journal of Advances in Management Research, 18(1), 113-135. doi:10.1108/jamr-06-2020-0104Maenhout, B., & Vanhoucke, M. (2013). An integrated nurse staffing and scheduling analysis for longer-term nursing staff allocation problems. Omega, 41(2), 485-499. doi:10.1016/j.omega.2012.01.002Benavides, A. J., Ritt, M., & Miralles, C. (2014). Flow shop scheduling with heterogeneous workers. European Journal of Operational Research, 237(2), 713-720. doi:10.1016/j.ejor.2014.02.012Miralles, C., García-Sabater, J. P., Andrés, C., & Cardós, M. (2008). Branch and bound procedures for solving the Assembly Line Worker Assignment and Balancing Problem: Application to Sheltered Work centres for Disabled. Discrete Applied Mathematics, 156(3), 352-367. doi:10.1016/j.dam.2005.12.012Moreira, M. C. O., Pastor, R., Costa, A. M., & Miralles, C. (2017). The multi-objective assembly line worker integration and balancing problem of type-2. Computers & Operations Research, 82, 114-125. doi:10.1016/j.cor.2017.01.003Bartlo, P., & Klein, P. J. (2011). Physical Activity Benefits and Needs in Adults With Intellectual Disabilities: Systematic Review of the Literature. American Journal on Intellectual and Developmental Disabilities, 116(3), 220-232. doi:10.1352/1944-7558-116.3.220Verdugo, M. A., Jordán de Urríes, F. B., Jenaro, C., Caballo, C., & Crespo, M. (2006). Quality of Life of Workers with an Intellectual Disability in Supported Employment. Journal of Applied Research in Intellectual Disabilities, 19(4), 309-316. doi:10.1111/j.1468-3148.2006.00277.xBossink, L. W. M., van der Putten, A. A., & Vlaskamp, C. (2017). Understanding low levels of physical activity in people with intellectual disabilities: A systematic review to identify barriers and facilitators. Research in Developmental Disabilities, 68, 95-110. doi:10.1016/j.ridd.2017.06.008Milner, A., LaMontagne, A. D., Aitken, Z., Bentley, R., & Kavanagh, A. M. (2014). Employment status and mental health among persons with and without a disability: evidence from an Australian cohort study. Journal of Epidemiology and Community Health, 68(11), 1064-1071. doi:10.1136/jech-2014-204147Nembhard, D. A., & Uzumeri, M. V. (2000). Experiential learning and forgetting for manual and cognitive tasks. International Journal of Industrial Ergonomics, 25(4), 315-326. doi:10.1016/s0169-8141(99)00021-9Siporin, S., & Lysack, C. (2004). Quality of Life and Supported Employment: A Case Study of Three Women With Developmental Disabilities. The American Journal of Occupational Therapy, 58(4), 455-465. doi:10.5014/ajot.58.4.455Buntinx, W. H. E., & Schalock, R. L. (2010). Models of Disability, Quality of Life, and Individualized Supports: Implications for Professional Practice in Intellectual Disability. Journal of Policy and Practice in Intellectual Disabilities, 7(4), 283-294. doi:10.1111/j.1741-1130.2010.00278.xQin, R., & Nembhard, D. A. (2015). Workforce agility in operations management. Surveys in Operations Research and Management Science, 20(2), 55-69. doi:10.1016/j.sorms.2015.11.001Rius-Sorolla, G., Maheut, J., Estellés-Miguel, S., & Garcia-Sabater, J. P. (2018). Coordination mechanisms with mathematical programming models for decentralized decision-making: a literature review. Central European Journal of Operations Research, 28(1), 61-104. doi:10.1007/s10100-018-0594-

Producció científica de l'ETSEIB a Futur. Articles publicats per investigadors de l'ETSEIB l'any 2017

Postprint (author's final draft