Documents disponibles écrits par cet auteur

Delay-dependent stabilization of discrete-time systems with time-varying delay via switching technique / Zhang Hui in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 134 N° 4 (Juillet 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 4 (Juillet 2012) . - 05 p. Titre : Delay-dependent stabilization of discrete-time systems with time-varying delay via switching technique Type de document : texte imprimé Auteurs : Zhang Hui, Auteur ; Shi, Yang, Auteur Année de publication : 2012 Article en page(s) : 05 p. Note générale : Dynamic systems Langues : Anglais (eng) Mots-clés : Discrete-time  systems  Randomly  time-varying  delays  Occurence  probability  Switching  controllers  Exponential  meansquare  stability  Linear  matrix  inequality Index. décimale : 629.8 Résumé : In this paper, we investigate the stabilization problem of time-delay discrete-time systems with occurrence probabilities for time delays. Using an augmenting technique, we convert random time-delay discrete-time systems to delay-free systems with stochastic variables. We propose to design a sequence of delay-dependent controllers. The implemented controller is chosen according to the measured time delay at each sampling instant. When the delay is randomly time-varying, the implemented controller is switched in a designed controller set. An example is provided to illustrate the effectiveness of the stability condition and another example is offered to show the applicability of the proposed design algorithm. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000004 [...] [article] Delay-dependent stabilization of discrete-time systems with time-varying delay via switching technique [texte imprimé] / Zhang Hui, Auteur ; Shi, Yang, Auteur . - 2012 . - 05 p. Dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 4 (Juillet 2012) . - 05 p. Mots-clés : Discrete-time  systems  Randomly  time-varying  delays  Occurence  probability  Switching  controllers  Exponential  meansquare  stability  Linear  matrix  inequality Index. décimale : 629.8 Résumé : In this paper, we investigate the stabilization problem of time-delay discrete-time systems with occurrence probabilities for time delays. Using an augmenting technique, we convert random time-delay discrete-time systems to delay-free systems with stochastic variables. We propose to design a sequence of delay-dependent controllers. The implemented controller is chosen according to the measured time delay at each sampling instant. When the delay is randomly time-varying, the implemented controller is switched in a designed controller set. An example is provided to illustrate the effectiveness of the stability condition and another example is offered to show the applicability of the proposed design algorithm. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000004 [...]

Landing string design and strength check in ultra-deepwater condition / Zhang Hui in Journal of natural gas science and engineering, Vol. 2 N° 4 (Septembre 2010) 

Public ISBD [article]  in Journal of natural gas science and engineering > Vol. 2 N° 4 (Septembre 2010) . - pp.178–182 Titre : Landing string design and strength check in ultra-deepwater condition Type de document : texte imprimé Auteurs : Zhang Hui, Auteur ; Gao Deli, Auteur ; Tang Haixiong, Auteur Année de publication : 2012 Article en page(s) : pp.178–182 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Ultra-deepwater  drilling  Landing  string  design  Strength  check  Bending  stress  Dynamic  load Résumé : Landing string used in ultra-deepwater casing running operations sustains complicated loads, including axial load, slip crushing load, bending load and dynamic load. Landing string design methods based on tension load are presented in detail. In these methods, sufficient margin of over pull is taken into account for the extreme axial load during surface casing running operations and environment loads caused by wave, current and vessel offset and heave. Landing string strength check is discussed to evaluate the safety of landing string in harsh environment. According to the analysis, slip crushing capacity is one of the critical limitations for landing string; bending stress caused by currents is great at the top of landing string at the beginning of operations while it will decrease by adjusting the vessel position after setting the casing below mud line. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S1875510010000375 [article] Landing string design and strength check in ultra-deepwater condition [texte imprimé] / Zhang Hui, Auteur ; Gao Deli, Auteur ; Tang Haixiong, Auteur . - 2012 . - pp.178–182. Génie Chimique Langues : Anglais (eng) in Journal of natural gas science and engineering > Vol. 2 N° 4 (Septembre 2010) . - pp.178–182 Mots-clés : Ultra-deepwater  drilling  Landing  string  design  Strength  check  Bending  stress  Dynamic  load Résumé : Landing string used in ultra-deepwater casing running operations sustains complicated loads, including axial load, slip crushing load, bending load and dynamic load. Landing string design methods based on tension load are presented in detail. In these methods, sufficient margin of over pull is taken into account for the extreme axial load during surface casing running operations and environment loads caused by wave, current and vessel offset and heave. Landing string strength check is discussed to evaluate the safety of landing string in harsh environment. According to the analysis, slip crushing capacity is one of the critical limitations for landing string; bending stress caused by currents is great at the top of landing string at the beginning of operations while it will decrease by adjusting the vessel position after setting the casing below mud line. ISSN : 1875-5100 En ligne : http://www.sciencedirect.com/science/article/pii/S1875510010000375