Documents disponibles écrits par cet auteur

Analysis of tall buildings with damped outriggers / Y. Chen in Journal of structural engineering, Vol. 136 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 11 (Novembre 2010) . - pp. 1435-1443 Titre : Analysis of tall buildings with damped outriggers Type de document : texte imprimé Auteurs : Y. Chen, Auteur ; D. M. McFarland, Auteur ; Z. Wang, Auteur Année de publication : 2011 Article en page(s) : pp. 1435-1443 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Free  vibration  Intermediate  rotational  damper  Closed-form  analytical  solution  Numerical  iteration  scheme  Optimal  damping  and  position Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A novel damped outrigger system has been recently proposed for tall buildings, and is quite promising. To gain insight into the conceptual design of such systems, a simple beam-damper system model for a building with such dampers installed is developed and studied. A partial differential equation governing the motion is derived assuming a Bernoulli-Euler beam. A closed-form analytical solution is developed for vibration of the beam by analyzing the regions above and below the damper separately using separation of variables. By applying appropriate boundary conditions at the ends, a transcendental characteristic equation is obtained that governs the system’s complex natural frequencies. An explicit form for the complex mode shape is determined for dynamic analysis. A numerical iteration scheme is adopted to solve the characteristic equation for the complex eigenvalues (i.e., the system modal frequencies and damping ratios). This solution was used to determine design curves for optimal damper position and size. For engineering convenience, empirical equations were provided by fitting numerical results. These equations include one for determining the optimal location of the damper for each mode, and two for determining the optimal damping coefficient of the damper, and for calculating the maximum modal damping ratio of the system while the beam vibrates in its first mode. Furthermore, relatively accurate approximations of the pseudoundamped natural frequency and damping ratio of the first mode were obtained using a Taylor expansion of the characteristic equation. All of the results obtained are nondimensionalized for convenience of analysis and application. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i11/p1435_s1?isAuthorized=no [article] Analysis of tall buildings with damped outriggers [texte imprimé] / Y. Chen, Auteur ; D. M. McFarland, Auteur ; Z. Wang, Auteur . - 2011 . - pp. 1435-1443. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 11 (Novembre 2010) . - pp. 1435-1443 Mots-clés : Free  vibration  Intermediate  rotational  damper  Closed-form  analytical  solution  Numerical  iteration  scheme  Optimal  damping  and  position Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A novel damped outrigger system has been recently proposed for tall buildings, and is quite promising. To gain insight into the conceptual design of such systems, a simple beam-damper system model for a building with such dampers installed is developed and studied. A partial differential equation governing the motion is derived assuming a Bernoulli-Euler beam. A closed-form analytical solution is developed for vibration of the beam by analyzing the regions above and below the damper separately using separation of variables. By applying appropriate boundary conditions at the ends, a transcendental characteristic equation is obtained that governs the system’s complex natural frequencies. An explicit form for the complex mode shape is determined for dynamic analysis. A numerical iteration scheme is adopted to solve the characteristic equation for the complex eigenvalues (i.e., the system modal frequencies and damping ratios). This solution was used to determine design curves for optimal damper position and size. For engineering convenience, empirical equations were provided by fitting numerical results. These equations include one for determining the optimal location of the damper for each mode, and two for determining the optimal damping coefficient of the damper, and for calculating the maximum modal damping ratio of the system while the beam vibrates in its first mode. Furthermore, relatively accurate approximations of the pseudoundamped natural frequency and damping ratio of the first mode were obtained using a Taylor expansion of the characteristic equation. All of the results obtained are nondimensionalized for convenience of analysis and application. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i11/p1435_s1?isAuthorized=no

Gas phase extraction of iron from its oxide in a fluidized bed reactor / L. Van Dyk in Minerals engineering, Vol. 23 N° 1 (Janvier 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 1 (Janvier 2010) . - pp. 58-60 Titre : Gas phase extraction of iron from its oxide in a fluidized bed reactor Type de document : texte imprimé Auteurs : L. Van Dyk, Auteur ; E. R. M. Mariba, Auteur ; Y. Chen, Auteur Article en page(s) : pp. 58-60 Note générale : Génie Minier Métallurgie Langues : Anglais (eng) Mots-clés : Extractive  metallurgy  Environmental  Iron  ores  Fine  particle  processing  Leaching Index. décimale : 622 Industrie minière Résumé : Interest in extraction processes that utilise organic ligands in the gas phase has been growing since such processes appear to eliminate many of the problems of high energy costs and complexity encountered in conventional hydrometallurgical and pyrometallurgical processes. The effect of temperature, ligand concentration and metal oxide concentration on such an iron extraction process was investigated. The ligand was introduced to the fluidized bed reactor containing the different concentrations of metal oxides at different flow rates through an evaporator. Gas phase extraction was shown to result in reasonable extractions in short periods of time, with iron extraction above 80% after 4 h for the low metal oxide concentration charge. The process was shown to depend on all the mentioned variables, and there is need to find a relationship which will be able to predict how extraction proceeds with time. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...] [article] Gas phase extraction of iron from its oxide in a fluidized bed reactor [texte imprimé] / L. Van Dyk, Auteur ; E. R. M. Mariba, Auteur ; Y. Chen, Auteur . - pp. 58-60. Génie Minier Métallurgie Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 1 (Janvier 2010) . - pp. 58-60 Mots-clés : Extractive  metallurgy  Environmental  Iron  ores  Fine  particle  processing  Leaching Index. décimale : 622 Industrie minière Résumé : Interest in extraction processes that utilise organic ligands in the gas phase has been growing since such processes appear to eliminate many of the problems of high energy costs and complexity encountered in conventional hydrometallurgical and pyrometallurgical processes. The effect of temperature, ligand concentration and metal oxide concentration on such an iron extraction process was investigated. The ligand was introduced to the fluidized bed reactor containing the different concentrations of metal oxides at different flow rates through an evaporator. Gas phase extraction was shown to result in reasonable extractions in short periods of time, with iron extraction above 80% after 4 h for the low metal oxide concentration charge. The process was shown to depend on all the mentioned variables, and there is need to find a relationship which will be able to predict how extraction proceeds with time. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VDR-4XDKC9K-1&_user=6 [...]

A hybrid genetic algorithmic approach to the maximally diverse grouping problem / Fan, Z. P. in Journal of the operational research society (JORS), Vol. 62 N° 1 (Janvier 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 1 (Janvier 2011) . - pp. 92–99 Titre : A hybrid genetic algorithmic approach to the maximally diverse grouping problem Type de document : texte imprimé Auteurs : Fan, Z. P., Auteur ; Y. Chen, Auteur ; Ma, J., Auteur Année de publication : 2011 Article en page(s) : pp. 92–99 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Genetic  algorithm  Maximally  diverse  grouping  problem  Local  neighbourhood  search Index. décimale : 001.424 Résumé : The maximally diverse grouping problem (MDGP) is a NP-complete problem. For such NP-complete problems, heuristics play a major role in searching for solutions. Most of the heuristics for MDGP focus on the equal group-size situation. In this paper, we develop a genetic algorithm (GA)-based hybrid heuristic to solve this problem considering not only the equal group-size situation but also the different group-size situation. The performance of the algorithm is compared with the established Lotfi–Cerveny–Weitz algorithm and the non-hybrid GA. Computational experience indicates that the proposed GA-based hybrid algorithm is a good tool for solving MDGP. Moreover, it can be easily modified to solve other equivalent problems. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n1/abs/jors2009168a.html [article] A hybrid genetic algorithmic approach to the maximally diverse grouping problem [texte imprimé] / Fan, Z. P., Auteur ; Y. Chen, Auteur ; Ma, J., Auteur . - 2011 . - pp. 92–99. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 1 (Janvier 2011) . - pp. 92–99 Mots-clés : Genetic  algorithm  Maximally  diverse  grouping  problem  Local  neighbourhood  search Index. décimale : 001.424 Résumé : The maximally diverse grouping problem (MDGP) is a NP-complete problem. For such NP-complete problems, heuristics play a major role in searching for solutions. Most of the heuristics for MDGP focus on the equal group-size situation. In this paper, we develop a genetic algorithm (GA)-based hybrid heuristic to solve this problem considering not only the equal group-size situation but also the different group-size situation. The performance of the algorithm is compared with the established Lotfi–Cerveny–Weitz algorithm and the non-hybrid GA. Computational experience indicates that the proposed GA-based hybrid algorithm is a good tool for solving MDGP. Moreover, it can be easily modified to solve other equivalent problems. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n1/abs/jors2009168a.html

A hybrid genetic algorithmic approach to the maximally diverse grouping problem / Fan, Z. P. in Journal of the operational research society (JORS), Vol. 62 N° 7 (Juillet 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 7 (Juillet 2011) . - pp. 1423–1430 Titre : A hybrid genetic algorithmic approach to the maximally diverse grouping problem Type de document : texte imprimé Auteurs : Fan, Z. P., Auteur ; Y. Chen, Auteur ; Ma, J., Auteur Année de publication : 2011 Article en page(s) : pp. 1423–1430 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Genetic  algorithm  Maximally  diverse  grouping  problem  Local  neighbourhood  search Index. décimale : 001.424 Résumé : The maximally diverse grouping problem (MDGP) is a NP-complete problem. For such NP-complete problems, heuristics play a major role in searching for solutions. Most of the heuristics for MDGP focus on the equal group-size situation. In this paper, we develop a genetic algorithm (GA)-based hybrid heuristic to solve this problem considering not only the equal group-size situation but also the different group-size situation. The performance of the algorithm is compared with the established Lotfi–Cerveny–Weitz algorithm and the non-hybrid GA. Computational experience indicates that the proposed GA-based hybrid algorithm is a good tool for solving MDGP. Moreover, it can be easily modified to solve other equivalent problems. Note de contenu : Corrections to: Journal of the Operational Research Society (2010). doi:10.1057/jors.2009.168; published online 6 January 2010 DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n7/abs/jors201092a.html [article] A hybrid genetic algorithmic approach to the maximally diverse grouping problem [texte imprimé] / Fan, Z. P., Auteur ; Y. Chen, Auteur ; Ma, J., Auteur . - 2011 . - pp. 1423–1430. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 7 (Juillet 2011) . - pp. 1423–1430 Mots-clés : Genetic  algorithm  Maximally  diverse  grouping  problem  Local  neighbourhood  search Index. décimale : 001.424 Résumé : The maximally diverse grouping problem (MDGP) is a NP-complete problem. For such NP-complete problems, heuristics play a major role in searching for solutions. Most of the heuristics for MDGP focus on the equal group-size situation. In this paper, we develop a genetic algorithm (GA)-based hybrid heuristic to solve this problem considering not only the equal group-size situation but also the different group-size situation. The performance of the algorithm is compared with the established Lotfi–Cerveny–Weitz algorithm and the non-hybrid GA. Computational experience indicates that the proposed GA-based hybrid algorithm is a good tool for solving MDGP. Moreover, it can be easily modified to solve other equivalent problems. Note de contenu : Corrections to: Journal of the Operational Research Society (2010). doi:10.1057/jors.2009.168; published online 6 January 2010 DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n7/abs/jors201092a.html