Documents disponibles écrits par cet auteur

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

Role of severe plastic deformation on the cyclic reversibility of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy / B. Kockar in Acta materialia, Vol. 58 N° 19 (Novembre 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 19 (Novembre 2010) . - pp. 6411–6420 Titre : Role of severe plastic deformation on the cyclic reversibility of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy Type de document : texte imprimé Auteurs : B. Kockar, Auteur ; K. C. Atli, Auteur ; Ma, J., Auteur Année de publication : 2011 Article en page(s) : pp. 6411–6420 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : TiNiPd  High  temperature  shape  memory  alloys  Severe  plastic  deformation  Equal  channel  angular  extrusion  Equal  channel  angular  pressing Résumé : The present work focuses on the effect of microstructural refinement on the thermo-mechanical cyclic stability of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy (HTSMA) which was severe plastically deformed using equal channel angular extrusion (ECAE). The grain/subgrain size of the high temperature austenite phase was refined down to about 100 nm, the lowest reported to date in HTSMAs. The increase in strength differential between the onset of transformation and the macroscopic plastic yielding after ECAE led to a notable enhancement in the cyclic stability during isobaric cooling–heating experiments. The reduction in irrecoverable strain levels was attributed to the increase in critical stress for dislocation slip due to the microstructural refinement during the ECAE process. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410005070 [article] Role of severe plastic deformation on the cyclic reversibility of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy [texte imprimé] / B. Kockar, Auteur ; K. C. Atli, Auteur ; Ma, J., Auteur . - 2011 . - pp. 6411–6420. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 19 (Novembre 2010) . - pp. 6411–6420 Mots-clés : TiNiPd  High  temperature  shape  memory  alloys  Severe  plastic  deformation  Equal  channel  angular  extrusion  Equal  channel  angular  pressing Résumé : The present work focuses on the effect of microstructural refinement on the thermo-mechanical cyclic stability of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy (HTSMA) which was severe plastically deformed using equal channel angular extrusion (ECAE). The grain/subgrain size of the high temperature austenite phase was refined down to about 100 nm, the lowest reported to date in HTSMAs. The increase in strength differential between the onset of transformation and the macroscopic plastic yielding after ECAE led to a notable enhancement in the cyclic stability during isobaric cooling–heating experiments. The reduction in irrecoverable strain levels was attributed to the increase in critical stress for dislocation slip due to the microstructural refinement during the ECAE process. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410005070

Superelastic cycling and room temperature recovery of Ti74Nb26 shape memory alloy / Ma, J. in Acta materialia, Vol. 58 N° 6 (Avril 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2216–2224 Titre : Superelastic cycling and room temperature recovery of Ti74Nb26 shape memory alloy Type de document : texte imprimé Auteurs : Ma, J., Auteur ; I. Karaman, Auteur ; H.J. Maier, Auteur Année de publication : 2011 Article en page(s) : pp. 2216–2224 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Superelasticity  Shape  memory  alloys  Martensitic  phase  transformation  Cyclic  behavior  Titanium  alloys Résumé : The superelastic cyclic response of Ti74Nb26 shape memory alloy (SMA), and the nature of cyclic evolution of its superelastic properties and their unexpected static recovery process after cycling, were investigated at room temperature. The critical stress for stress-induced martensitic transformation (σSIM) and stress hysteresis (Δσ) continuously decrease with increasing number of superelastic cycles. However, cumulative irrecoverable strain during cycling in samples of particular processing conditions increases only up to a certain number of cycles before decreasing with further cycling. Stress-free aging at room temperature after cycling was shown to increase σSIM and Δσ. The unexpected room temperature recovery is attributed to the recovery of retained martensite and point defects. Similar experiments conducted on conventional Ni-rich Ni–Ti SMAs also show static recovery at room temperature, indicating that the recovery process is not unique to Ti–Nb SMAs. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008519 [article] Superelastic cycling and room temperature recovery of Ti74Nb26 shape memory alloy [texte imprimé] / Ma, J., Auteur ; I. Karaman, Auteur ; H.J. Maier, Auteur . - 2011 . - pp. 2216–2224. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2216–2224 Mots-clés : Superelasticity  Shape  memory  alloys  Martensitic  phase  transformation  Cyclic  behavior  Titanium  alloys Résumé : The superelastic cyclic response of Ti74Nb26 shape memory alloy (SMA), and the nature of cyclic evolution of its superelastic properties and their unexpected static recovery process after cycling, were investigated at room temperature. The critical stress for stress-induced martensitic transformation (σSIM) and stress hysteresis (Δσ) continuously decrease with increasing number of superelastic cycles. However, cumulative irrecoverable strain during cycling in samples of particular processing conditions increases only up to a certain number of cycles before decreasing with further cycling. Stress-free aging at room temperature after cycling was shown to increase σSIM and Δσ. The unexpected room temperature recovery is attributed to the recovery of retained martensite and point defects. Similar experiments conducted on conventional Ni-rich Ni–Ti SMAs also show static recovery at room temperature, indicating that the recovery process is not unique to Ti–Nb SMAs. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008519