Examinando por Materia "Optimization problems"

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    Ítem
    Integrating design for assembly guidelines in packaging design with a context-based approach
    (Elsevier, 2014-01-01) Betancur-Muñoz, P.; Osorio-Gómeza, G.; Martínez-Cadavid, J.F.; Duque-Lombana, J.F.
    In the product lifecycle, the packaging, as an object, has been on the back burner with respect to product and production systems design and some authors stated that its influence starts at the packing stage and ends when the customer obtains the product. Only a few years ago, its strategic role, protecting, containing and preserving the product, has been recognized, both in theory and in practice [1]. In this way, the packaging design has been focused in the accomplishment of some specific objectives, such as cost and space saving, material reduction, and quality problems avoidance. These approaches are object-related, but the design process is not considering that the packaging is also utilized to handle, transport, distribute, retail and promote the product. Therefore, even if mathematical solutions could be obtained for space optimization problems, these could not be relevant at industrial level since they are unfeasible throughout the packaging lifecycle, from either logistics or quality standpoints; and new restrictions should be considered. An approach proposed by Lee & Lye [2], called "Design for manual Packaging (DFPkg)", is based on Design for the Environment (DFEnv) and Design for Assembly (DFA) guidelines, since the activities related with packaging could be considered as assembly activities seeing that all the packed pieces are part of a unique system. Nevertheless, some guidelines from DFA are omitted or decontextualized and they are not connected to restrictions in the mathematical models. This paper presents an integral approach for packaging design, complementing the guidelines proposed by Lee & Lye [2] in key contexts of the packaging lifecycle, in order to generate restrictions for an optimization model. Besides, this approach has been validated with a real industrial case study where the obtained solution is compared with the current one. © 2014 Published by Elsevier B.V.
  • No hay miniatura disponible
    Ítem
    Integrating design for assembly guidelines in packaging design with a context-based approach
    (Elsevier, 2014-01-01) Betancur-Muñoz, P.; Osorio-Gómeza, G.; Martínez-Cadavid, J.F.; Duque-Lombana, J.F.; Betancur-Muñoz, P.; Osorio-Gómeza, G.; Martínez-Cadavid, J.F.; Duque-Lombana, J.F.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
    In the product lifecycle, the packaging, as an object, has been on the back burner with respect to product and production systems design and some authors stated that its influence starts at the packing stage and ends when the customer obtains the product. Only a few years ago, its strategic role, protecting, containing and preserving the product, has been recognized, both in theory and in practice [1]. In this way, the packaging design has been focused in the accomplishment of some specific objectives, such as cost and space saving, material reduction, and quality problems avoidance. These approaches are object-related, but the design process is not considering that the packaging is also utilized to handle, transport, distribute, retail and promote the product. Therefore, even if mathematical solutions could be obtained for space optimization problems, these could not be relevant at industrial level since they are unfeasible throughout the packaging lifecycle, from either logistics or quality standpoints; and new restrictions should be considered. An approach proposed by Lee & Lye [2], called "Design for manual Packaging (DFPkg)", is based on Design for the Environment (DFEnv) and Design for Assembly (DFA) guidelines, since the activities related with packaging could be considered as assembly activities seeing that all the packed pieces are part of a unique system. Nevertheless, some guidelines from DFA are omitted or decontextualized and they are not connected to restrictions in the mathematical models. This paper presents an integral approach for packaging design, complementing the guidelines proposed by Lee & Lye [2] in key contexts of the packaging lifecycle, in order to generate restrictions for an optimization model. Besides, this approach has been validated with a real industrial case study where the obtained solution is compared with the current one. © 2014 Published by Elsevier B.V.
  • No hay miniatura disponible
    Ítem
    Sensitivity analysis in optimized parametric curve fitting
    (EMERALD GROUP PUBLISHING LIMITED, 2015-03-02) Ruiz, Oscar E.; Cortes, Camilo; Acosta, Diego A.; Aristizabal, Mauricio; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Purpose-Curve fitting from unordered noisy point samples is needed for surface reconstruction in many applications. In the literature, several approaches have been proposed to solve this problem. However, previous works lack formal characterization of the curve fitting problem and assessment on the effect of several parameters (i.e. scalars that remain constant in the optimization problem), such as control points number (m), curve degree (b), knot vector composition (U), norm degree (k ), and point sample size (r) on the optimized curve reconstruction measured by a penalty function ( f ). The paper aims to discuss these issues. Design/methodology/approach-A numerical sensitivity analysis of the effect of m, b, k and r on f and a characterization of the fitting procedure from the mathematical viewpoint are performed. Also, the spectral (frequency) analysis of the derivative of the angle of the fitted curve with respect to u as a means to detect spurious curls and peaks is explored. Findings-It is more effective to find optimum values for m than k or b in order to obtain good results because the topological faithfulness of the resulting curve strongly depends on m. Furthermore, when an exaggerate number of control points is used the resulting curve presents spurious curls and peaks. The authors were able to detect the presence of such spurious features with spectral analysis. Also, the authors found that the method for curve fitting is robust to significant decimation of the point sample. Research limitations/implications-The authors have addressed important voids of previous works in this field. The authors determined, among the curve fitting parameters m, b and k, which of them influenced the most the results and how. Also, the authors performed a characterization of the curve fitting problem from the optimization perspective. And finally, the authors devised a method to detect spurious features in the fitting curve. Practical implications-This paper provides a methodology to select the important tuning parameters in a formal manner. Originality/value-Up to the best of the knowledge, no previous work has been conducted in the formal mathematical evaluation of the sensitivity of the goodness of the curve fit with respect to different possible tuning parameters (curve degree, number of control points, norm degree, etc.). © Emerald Group Publishing Limited.
  • No hay miniatura disponible
    Ítem
    Sensitivity analysis in optimized parametric curve fitting
    (EMERALD GROUP PUBLISHING LIMITED, 2015-03-02) Ruiz, Oscar E.; Cortes, Camilo; Acosta, Diego A.; Aristizabal, Mauricio; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
    Purpose-Curve fitting from unordered noisy point samples is needed for surface reconstruction in many applications. In the literature, several approaches have been proposed to solve this problem. However, previous works lack formal characterization of the curve fitting problem and assessment on the effect of several parameters (i.e. scalars that remain constant in the optimization problem), such as control points number (m), curve degree (b), knot vector composition (U), norm degree (k ), and point sample size (r) on the optimized curve reconstruction measured by a penalty function ( f ). The paper aims to discuss these issues. Design/methodology/approach-A numerical sensitivity analysis of the effect of m, b, k and r on f and a characterization of the fitting procedure from the mathematical viewpoint are performed. Also, the spectral (frequency) analysis of the derivative of the angle of the fitted curve with respect to u as a means to detect spurious curls and peaks is explored. Findings-It is more effective to find optimum values for m than k or b in order to obtain good results because the topological faithfulness of the resulting curve strongly depends on m. Furthermore, when an exaggerate number of control points is used the resulting curve presents spurious curls and peaks. The authors were able to detect the presence of such spurious features with spectral analysis. Also, the authors found that the method for curve fitting is robust to significant decimation of the point sample. Research limitations/implications-The authors have addressed important voids of previous works in this field. The authors determined, among the curve fitting parameters m, b and k, which of them influenced the most the results and how. Also, the authors performed a characterization of the curve fitting problem from the optimization perspective. And finally, the authors devised a method to detect spurious features in the fitting curve. Practical implications-This paper provides a methodology to select the important tuning parameters in a formal manner. Originality/value-Up to the best of the knowledge, no previous work has been conducted in the formal mathematical evaluation of the sensitivity of the goodness of the curve fit with respect to different possible tuning parameters (curve degree, number of control points, norm degree, etc.). © Emerald Group Publishing Limited.