Documents disponibles écrits par cet auteur

Mechanical model parameters for viscoelastic dampers / Chang, T.-S. in Journal of engineering mechanics, Vol. 135 N° 6 (Juin 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 6 (Juin 2009) . - pp. 581-584 Titre : Mechanical model parameters for viscoelastic dampers Type de document : texte imprimé Auteurs : Chang, T.-S., Auteur ; M. P. Singh, Auteur Article en page(s) : pp. 581-584 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Mechanical  properties  Parameters  Viscoelasticity  Damping. Résumé : Models of varying complexities are being used to represent the frequency-dependent dynamic force deformation characteristics of viscoelastic dampers. More sophisticated models with real or complex fractional derivatives can definitely capture the frequency-dependent properties better. However, since these advanced models add complexity in the analysis of structures, the use of two classical models—a Kelvin chain and a Maxwell ladder—consisting of usual dashpots and springs is suggested. In this technical note, we provide explicit steps and necessary formulas to calculate the parameters of these two proposed models to provide desired frequency-dependent characteristics represented by the storage and loss moduli. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Mechanical model parameters for viscoelastic dampers [texte imprimé] / Chang, T.-S., Auteur ; M. P. Singh, Auteur . - pp. 581-584. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 6 (Juin 2009) . - pp. 581-584 Mots-clés : Mechanical  properties  Parameters  Viscoelasticity  Damping. Résumé : Models of varying complexities are being used to represent the frequency-dependent dynamic force deformation characteristics of viscoelastic dampers. More sophisticated models with real or complex fractional derivatives can definitely capture the frequency-dependent properties better. However, since these advanced models add complexity in the analysis of structures, the use of two classical models—a Kelvin chain and a Maxwell ladder—consisting of usual dashpots and springs is suggested. In this technical note, we provide explicit steps and necessary formulas to calculate the parameters of these two proposed models to provide desired frequency-dependent characteristics represented by the storage and loss moduli. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]

Optimal system design series-network DEA models / Wei, Q. L. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1109–1119 Titre : Optimal system design series-network DEA models Type de document : texte imprimé Auteurs : Wei, Q. L., Auteur ; Chang, T.-S., Auteur Année de publication : 2011 Article en page(s) : pp. 1109–1119 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Network  DEA  Optimal  system  design  Resource  allocation  Budget Index. décimale : 001.424 Résumé : There is an urgent need in a wide range of fields such as logistics and supply chain management to develop effective approaches to measure and/or optimally design a network system comprised of a set of units. Data envelopment analysis (DEA) researchers have been developing network DEA models to measure decision making units’ (DMUs’) network systems. However, to our knowledge, there are no previous contributions on the DEA-type models that help DMUs optimally design their network systems. The need to design optimal systems is quite common and is sometimes necessary in practice. This research thus introduces a new type of DEA model termed the optimal system design (OSD) network DEA model to optimally design a DMUs (exogenous and endogenous) input and (endogenous and final) output portfolios in terms of profit maximization given the DMUs total available budget. The resulting optimal network design through the proposed OSD network DEA models is efficient, that is, it lies on the frontier of the corresponding production possibility set. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201045a.html [article] Optimal system design series-network DEA models [texte imprimé] / Wei, Q. L., Auteur ; Chang, T.-S., Auteur . - 2011 . - pp. 1109–1119. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1109–1119 Mots-clés : Data  envelopment  analysis  Network  DEA  Optimal  system  design  Resource  allocation  Budget Index. décimale : 001.424 Résumé : There is an urgent need in a wide range of fields such as logistics and supply chain management to develop effective approaches to measure and/or optimally design a network system comprised of a set of units. Data envelopment analysis (DEA) researchers have been developing network DEA models to measure decision making units’ (DMUs’) network systems. However, to our knowledge, there are no previous contributions on the DEA-type models that help DMUs optimally design their network systems. The need to design optimal systems is quite common and is sometimes necessary in practice. This research thus introduces a new type of DEA model termed the optimal system design (OSD) network DEA model to optimally design a DMUs (exogenous and endogenous) input and (endogenous and final) output portfolios in terms of profit maximization given the DMUs total available budget. The resulting optimal network design through the proposed OSD network DEA models is efficient, that is, it lies on the frontier of the corresponding production possibility set. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201045a.html

Routing strategies for integrating forward distribution and reverse collection / Chang, T.-S. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 971–981 Titre : Routing strategies for integrating forward distribution and reverse collection Type de document : texte imprimé Auteurs : Chang, T.-S., Auteur ; Liao, Y.-F., Auteur Année de publication : 2011 Article en page(s) : pp. 971–981 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Routing  Traveling  salesman  path  problem  Pickup  and  delivery  Reverse  logistics Index. décimale : 001.424 Résumé : Due to the significant growth in the demand for logistics services and the ongoing trend towards the outsourcing of logistics activities, logistics service providers have concurrently gained a significant profit-making opportunity and faced the unprecedented challenge of surviving in the midst of increasingly fierce market competition. This research thus aims to propose routing strategies that optimally integrate forward distribution and reverse collection to help logistics service providers reduce their operating costs when providing transportation services, and thus improve their market competitive power. The integrated routing problem is formulated as the mixed pickup-delivery asymmetric traveling salesman path problem. The problem is NP-hard and new in the literature. Therefore, the objectives of this research are to first model the problem and then develop an efficient and effective heuristic solution algorithm to the problem. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201021a.html [article] Routing strategies for integrating forward distribution and reverse collection [texte imprimé] / Chang, T.-S., Auteur ; Liao, Y.-F., Auteur . - 2011 . - pp. 971–981. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 971–981 Mots-clés : Routing  Traveling  salesman  path  problem  Pickup  and  delivery  Reverse  logistics Index. décimale : 001.424 Résumé : Due to the significant growth in the demand for logistics services and the ongoing trend towards the outsourcing of logistics activities, logistics service providers have concurrently gained a significant profit-making opportunity and faced the unprecedented challenge of surviving in the midst of increasingly fierce market competition. This research thus aims to propose routing strategies that optimally integrate forward distribution and reverse collection to help logistics service providers reduce their operating costs when providing transportation services, and thus improve their market competitive power. The integrated routing problem is formulated as the mixed pickup-delivery asymmetric traveling salesman path problem. The problem is NP-hard and new in the literature. Therefore, the objectives of this research are to first model the problem and then develop an efficient and effective heuristic solution algorithm to the problem. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201021a.html

Seismic analysis of structures with viscoelastic dampers / M. P. Singh in Journal of engineering mechanics, Vol. 135 N° 6 (Juin 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 6 (Juin 2009) . - pp. 571-580 Titre : Seismic analysis of structures with viscoelastic dampers Type de document : texte imprimé Auteurs : M. P. Singh, Auteur ; Chang, T.-S., Auteur Article en page(s) : pp. 571-580 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Seismic  analysis  Viscoelasticity  Damping  Structural  control. Résumé : Viscoelastic dampers are being used in structures to mitigate dynamic effects. The models of varying complexities from simple maxwell element to differential models with fractional and complex order derivatives have been used to represent their frequency-dependent force deformation characteristics. More complex models are able to capture the frequency dependence of the material properties better, but are difficult to use in analyses. However, the classical models consisting of assemblies of Kelvin and/or Maxwell elements with an adequate number of parameters can be formed to capture the frequency dependence as accurately as the more sophisticated fractional derivative models can do. The main advantage in adopting these classical models is a simpler and smaller system of equations, which can be conveniently analyzed for nonlinear and linear systems. In this study, the two classical mechanical models consisting of Kelvin chains and Maxwell ladder are used. It is shown that these mechanical models are as effective as the fractional derivative model in capturing the effect of the frequency dependence of the material properties in response calculations and are more convenient to use in dynamic response analyses. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Seismic analysis of structures with viscoelastic dampers [texte imprimé] / M. P. Singh, Auteur ; Chang, T.-S., Auteur . - pp. 571-580. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 6 (Juin 2009) . - pp. 571-580 Mots-clés : Seismic  analysis  Viscoelasticity  Damping  Structural  control. Résumé : Viscoelastic dampers are being used in structures to mitigate dynamic effects. The models of varying complexities from simple maxwell element to differential models with fractional and complex order derivatives have been used to represent their frequency-dependent force deformation characteristics. More complex models are able to capture the frequency dependence of the material properties better, but are difficult to use in analyses. However, the classical models consisting of assemblies of Kelvin and/or Maxwell elements with an adequate number of parameters can be formed to capture the frequency dependence as accurately as the more sophisticated fractional derivative models can do. The main advantage in adopting these classical models is a simpler and smaller system of equations, which can be conveniently analyzed for nonlinear and linear systems. In this study, the two classical mechanical models consisting of Kelvin chains and Maxwell ladder are used. It is shown that these mechanical models are as effective as the fractional derivative model in capturing the effect of the frequency dependence of the material properties in response calculations and are more convenient to use in dynamic response analyses. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]