Instituto Superior Técnico

About: Instituto Superior Técnico is a based out in . It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 10085 authors who have published 30226 publications receiving 667524 citations. The organization is also known as: IST & Instituto Superior Tecnico.

Issues, progress and new results in robust adaptive control

Abstract: We overview recent progress in the field of robust adaptive control with special emphasis on methodologies that use multiple-model architectures. We argue that the selection of the number of models, estimators and compensators in such architectures must be based on a precise definition of the robust performance requirements. We illustrate some of the concepts and outstanding issues by presenting a new methodology that blends robust non-adaptive mixed µ-synthesis designs and stochastic hypothesis-testing concepts leading to the so-called robust multiple model adaptive control (RMMAC) architecture. A numerical example is used to illustrate the RMMAC design methodology, as well as its strengths and potential shortcomings. The later motivated us to develop a variant architecture, denoted as RMMAC/XI, that can be effectively used in highly uncertain exogenous plant disturbance environments. Copyright © 2006 John Wiley & Sons, Ltd.

Observed Ds(2317) and tentative D(2100-2300) as the charmed cousins of the light scalar nonet.

Abstract: The very recently observed ${D}_{sJ}^{*}(2317{)}^{+}$ meson is described as a quasibound scalar $c\overline{s}$ state in a unitarized meson model, owing its existence to the strong $^{3}P_{0}$ Okubo-Zweig-Iizuka\char21{}allowed coupling to the nearby $S$-wave $DK$ threshold. By the same mechanism, a scalar ${D}_{0}^{*}(2100\char21{}2300)$ resonance is predicted above the $D\ensuremath{\pi}$ threshold. These scalars are the charmed cousins of the light scalar nonet ${f}_{0}(600)$, ${f}_{0}(980)$, ${K}_{0}^{*}(800)$, and ${a}_{0}(980)$, reproduced by the same model. The standard $c\overline{n}$ and $c\overline{s}$ charmed scalars ${D}_{0}$ and ${D}_{s0}$, cousins of the scalar nonet ${f}_{0}(1370)$, ${f}_{0}(1500)$, ${K}_{0}^{*}(1430)$, and ${a}_{0}(1450)$, are predicted to lie at about 2.64 and 2.79 GeV, respectively, both with a width of some 200 MeV.