38 research outputs found

    Golden Ball Algorithm for solving Flow Shop Scheduling Problem

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    The Flow Shop Scheduling Problem (FSSP) is notoriously NP-hard combinatorial optimization problem. The goal is to find a schedule that minimizes the makespan. This paper proposes an adaptation of a new approach called Golden Ball Algorithm (GBA). The proposed algorithm has been never tested with FSSP; it’s based on soccer concept to obtain the optimal solution. Numerical results are presented for 22 instances of OR- Library. The computational results indicate that this approach is practical for small OR-Library instances

    Spatial-temporal data modelling and processing for personalised decision support

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    The purpose of this research is to undertake the modelling of dynamic data without losing any of the temporal relationships, and to be able to predict likelihood of outcome as far in advance of actual occurrence as possible. To this end a novel computational architecture for personalised ( individualised) modelling of spatio-temporal data based on spiking neural network methods (PMeSNNr), with a three dimensional visualisation of relationships between variables is proposed. In brief, the architecture is able to transfer spatio-temporal data patterns from a multidimensional input stream into internal patterns in the spiking neural network reservoir. These patterns are then analysed to produce a personalised model for either classification or prediction dependent on the specific needs of the situation. The architecture described above was constructed using MatLab© in several individual modules linked together to form NeuCube (M1). This methodology has been applied to two real world case studies. Firstly, it has been applied to data for the prediction of stroke occurrences on an individual basis. Secondly, it has been applied to ecological data on aphid pest abundance prediction. Two main objectives for this research when judging outcomes of the modelling are accurate prediction and to have this at the earliest possible time point. The implications of these findings are not insignificant in terms of health care management and environmental control. As the case studies utilised here represent vastly different application fields, it reveals more of the potential and usefulness of NeuCube (M1) for modelling data in an integrated manner. This in turn can identify previously unknown (or less understood) interactions thus both increasing the level of reliance that can be placed on the model created, and enhancing our human understanding of the complexities of the world around us without the need for over simplification. Read less Keywords Personalised modelling; Spiking neural network; Spatial-temporal data modelling; Computational intelligence; Predictive modelling; Stroke risk predictio

    Spatial-temporal data modelling and processing for personalised decision support

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    The purpose of this research is to undertake the modelling of dynamic data without losing any of the temporal relationships, and to be able to predict likelihood of outcome as far in advance of actual occurrence as possible. To this end a novel computational architecture for personalised ( individualised) modelling of spatio-temporal data based on spiking neural network methods (PMeSNNr), with a three dimensional visualisation of relationships between variables is proposed. In brief, the architecture is able to transfer spatio-temporal data patterns from a multidimensional input stream into internal patterns in the spiking neural network reservoir. These patterns are then analysed to produce a personalised model for either classification or prediction dependent on the specific needs of the situation. The architecture described above was constructed using MatLab© in several individual modules linked together to form NeuCube (M1). This methodology has been applied to two real world case studies. Firstly, it has been applied to data for the prediction of stroke occurrences on an individual basis. Secondly, it has been applied to ecological data on aphid pest abundance prediction. Two main objectives for this research when judging outcomes of the modelling are accurate prediction and to have this at the earliest possible time point. The implications of these findings are not insignificant in terms of health care management and environmental control. As the case studies utilised here represent vastly different application fields, it reveals more of the potential and usefulness of NeuCube (M1) for modelling data in an integrated manner. This in turn can identify previously unknown (or less understood) interactions thus both increasing the level of reliance that can be placed on the model created, and enhancing our human understanding of the complexities of the world around us without the need for over simplification. Read less Keywords Personalised modelling; Spiking neural network; Spatial-temporal data modelling; Computational intelligence; Predictive modelling; Stroke risk predictio

    SimLack: simulation-based optimization and scheduling of generic powder coating lines

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    https://www.asim2018.de/Powder coating and paint-spray lines are often complex production plants because of many dynamical dependencies, limited buffer space and sequence dependent changeover times. We have developed a generic simulation and optimization platform that enables the engineers to design more performant and energy efficient facilities and the production planners to increase productivity through simulation-based optimization. The simulation environment builds on a generic modelling library that captures all variations of such facilities. Execuable models are generated automatically from annotated CAD layouts. As a result, the system smoothly integrates with the engineering process. Once the facility is in use, the fully specified virtual plant is used for simulation-based scheduling, employing a combination of a generic priority-based heuristic and a variant of simulated annealing. We discuss how these two aspects of the system render it an important innovation for the painting line industry and show first results from the scheduling system

    Realization of an Optimal Schedule for the Two-machine Flow-Shop with Interval Job Processing Times

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    Non-preemptive two-machine flow-shop scheduling problem with uncertain processing times of n jobs is studied. In an uncertain version of a scheduling problem, there may not exist a unique schedule that remains optimal for all possible realizations of the job processing times. We find necessary and sufficient conditions (Theorem 1) when there exists a dominant permutation that is optimal for all possible realizations of the job processing times. Our computational studies show the percentage of the problems solvable under these conditions for the cases of randomly generated instances with n ≤ 100 . We also show how to use additional information about the processing times of the completed jobs during optimal realization of a schedule (Theorems 2 – 4). Computational studies for randomly generated instances with n ≤ 50 show the percentage of the two- machine flow-shop scheduling problems solvable under the sufficient conditions given in Theorems 2 – 4

    Heuristic for flow shop sequencing with separated and sequence independent setup times

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    This paper deals with the permutation flow shop scheduling problem with separated and sequence-independent machine setup times. A heuristic method with the objective of minimizing the total time to complete the schedule is introduced. The proposed heuristic is based on a structural property of this scheduling problem, which provides an upper bound on the idle time of the machines between the completion of the setup task and the beginning of job processing. Experimental results show that the new heuristic outperforms two existing ones.(CNPq) National Council for Scientific and Technological Developmen

    Discrete penguins search optimization algorithm to solve flow shop scheduling problem

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    Flow shop scheduling problem is one of the most classical NP-hard optimization problem. Which aims to find the best planning that minimizes the makespan (total completion time) of a set of tasks in a set of machines with certain constraints. In this paper, we propose a new nature inspired metaheuristic to solve the flow shop scheduling problem (FSSP), called penguins search optimization algorithm (PeSOA) based on collaborative hunting strategy of penguins.The operators and parameter values of PeSOA redefined to solve this problem. The performance of the penguins search optimization algorithm is tested on a set of benchmarks instances of FSSP from OR-Library, The results of the tests show that PeSOA is superior to some other metaheuristics algorithms, in terms of the quality of the solutions found and the execution time

    Un modelo para definir la programación de la producción en un taller de flujo con tiempos de cambio de partida dependientes considerando productividad y ergonomía

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    [EN] The manufacturer industry is characterized by the presence of highly repetitive movements, which is a major risk factor associated with work musculoskeletal disorders (WMSDs). Moreover, this risk factor worsens when workers do not take adequate rest periods. This paper analyzes the problem and presents a mixed integer linear programming (MILP) mathematical model to minimize makespan in an n¿job flow-shop problem with sequence-dependent setup times by considering recovery times. To this end, the model combines the effectiveness of MILP mathematical model optimization with the OCRA ergonomic assessment method. The model calculates work-recovery periods in workers¿ schedules based on the OCRA included in standards UNE¿EN 1005¿5:2007 and ISO 11228¿3:2007. Finally, a case study in a Food Sector Company is described.[ES] La industria manufacturera se caracteriza por la presencia de una elevada repetitividad de movimientos de sus trabajadores, siendo éste un importante factor de riesgo asociado con los trastornos musculoesqueléticos (TME) de origen laboral. Además, dicho factor de riesgo empeora cuando los trabajadores no realizan períodos de descanso adecuados. Este artículo analiza dicha problemática y presenta un modelo matemático de Programación Lineal Entera Mixta (PLEM) para minimizar el makespan en un problema de secuenciación flow-shop de n-trabajos con tiempos de setup dependientes de la secuencia, considerando los tiempos de recuperación de los trabajadores. Para ello, el modelo combina la efectividad de la optimización del modelo matemático de PLEM con el método de evaluación ergonómica OCRA. El modelo calcula los períodos de recuperación de los trabajadores según el método OCRA incluido en las normas UNE-EN 1005-5: 2007 e ISO 11228-3: 2007. Finalmente, se describe un caso de estudio en una empresa del sector alimentario.Asensio Cuesta, S.; Gómez-Gasquet, P. (2017). A model to define setup time sequence dependent flow shop scheduling considering productivity and ergonomic. Dyna. New Technologies. 5:1-15. doi:10.6036/NT8632S115

    A comprehensive review and evaluation of permutation flowshop heuristics to minimize flowtime

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    [EN] In recent years, a large number of heuristics have been proposed for the minimization of the total or mean flowtime/completion time of the well-known permutation flowshop scheduling problem. Although some literature reviews and comparisons have been made, they do not include the latest available heuristics and results are hard to compare as no common benchmarks and computing platforms have been employed. Furthermore, existing partial comparisons lack the application of powerful statistical tools. The result is that it is not clear which heuristics, especially among the recent ones, are the best. This paper presents a comprehensive review and computational evaluation as well as a statistical assessment of 22 existing heuristics. From the knowledge obtained after such a detailed comparison, five new heuristics are presented. Careful designs of experiments and analyses of variance (ANOVA) techniques are applied to guarantee sound conclusions. The comparison results identify the best existing methods and show that the five newly presented heuristics are competitive or better than the best performing ones in the literature for the permutation flowshop problem with the total completion time criterionThis research is partially supported by National Science Foundation of China (60874075, 61174187), and Science Foundation of Shandong Province, China (BS2010DX005), and Postdoctoral Science Foundation of China (20100480897). Ruben Ruiz is partially funded by the Spanish Ministry of Science and Innovation, under the project "SMPA-Advanced Parallel Multiobjective Sequencing: Practical and Theorerical Advances" with reference DPI2008-03511/DPI and by the Small and Medium Industry of the Generalitat Valenciana (IMPIVA) and by the European Union through the European Regional Development Fund (FEDER) inside the R+D program "Ayudas dirigidas a Institutos Tecnologicos de la Red IMPIVA" during the year 2011, with project number IMDEEA/2011/142.Pan, Q.; Ruiz García, R. (2013). A comprehensive review and evaluation of permutation flowshop heuristics to minimize flowtime. Computers and Operations Research. 40(1):117-128. https://doi.org/10.1016/j.cor.2012.05.018S11712840
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