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991.
Hartmut Logemann Richard Rebarber Stuart Townley 《Transactions of the American Mathematical Society》2003,355(8):3301-3328
Suppose that a static-state feedback stabilizes a continuous-time linear infinite-dimensional control system. We consider the following question: if we construct a sampled-data controller by applying an idealized sample-and-hold process to a continuous-time stabilizing feedback, will this sampled-data controller stabilize the system for all sufficiently small sampling times? Here the state space and the control space are Hilbert spaces, the system is of the form , where is the generator of a strongly continuous semigroup on , and the continuous time feedback is . The answer to the above question is known to be ``yes' if and are finite-dimensional spaces. In the infinite-dimensional case, if is not compact, then it is easy to find counterexamples. Therefore, we restrict attention to compact feedback. We show that the answer to the above question is ``yes', if is a bounded operator from into . Moreover, if is unbounded, we show that the answer ``yes' remains correct, provided that the semigroup generated by is analytic. We use the theory developed for static-state feedback to obtain analogous results for dynamic-output feedback control.
992.
Mario Schubert Hartmut Oschkinat Peter Schmieder 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2001,153(2):186
Amino acid type-selective experiments can help to remove ambiguities in automated assignment procedures for 15N/13C-labeled proteins. Here we present five triple-resonance experiments that yield amino acid type-selective 1H–15N correlations for aromatic amino acids. Four of the novel experiments are based on the MUSIC coherence transfer scheme that replaces the initial INEPT transfer and is selective for CH2. The MUSIC sequence is combined with selective excitation pulses to create experiments for Trp (W-HSQC) as well as Phe, Tyr, and His (FYH-HSQC). In addition, an experiment selective for Trp H1–N1 is presented. The new experiments are recorded as two-dimensional experiments and their performance is demonstrated with the application to a protein domain of 115 amino acids. 相似文献
993.
A general control model under uncertainty is considered. Using a Bayesian approach and dynamic programming, we investigate structural properties of optimal decision rules. In particular, we show the monotonicity of the total expected reward and of the so-called Gittins-Index. We extend the stopping rule and the stay-on-a-winner rule, which are well-known in bandit problems. Our approach is based on the multivariate likelihood ratio order andTP
2 functions. 相似文献
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We use semiclassical methods to discuss the scaling behaviour of quarkonium level splittings up to . Special emphasis is laid on the effects of asymptotic freedom which are found to be essential for . The bound t system will almost look like the ? system except that is larger than 0.8. In the ? system R will already be close to 0.8. 相似文献