128,487 research outputs found
Control and Filtering for Discrete Linear Repetitive Processes with H infty and ell 2--ell infty Performance
No full textRepetitive processes are characterized by a series of sweeps, termed passes, through a set of dynamics defined over a finite duration known as the pass length. On each pass an output, termed the pass profile, is produced which acts as a forcing function on, and hence contributes to, the dynamics of the next pass profile. This can lead to oscillations which increase in amplitude in the pass to pass direction and cannot be controlled by standard control laws. Here we give new results on the design of physically based control laws for the sub-class of so-called discrete linear repetitive processes which arise in applications areas such as iterative learning control. The main contribution is to show how control law design can be undertaken within the framework of a general robust filtering problem with guaranteed levels of performance. In particular, we develop algorithms for the design of an H? and dynamic output feedback controller and filter which guarantees that the resulting controlled (filtering error) process, respectively, is stable along the pass and has prescribed disturbance attenuation performance as measured by and – norms
On a transmission problem for equation and dynamic boundary condition of Cahn–Hilliard type with nonsmooth potentials
No full textThis paper is concerned with well-posedness of the Cahn–Hilliard equation subject to a class of new dynamic boundary conditions. The system was recently derived in Liu–Wu (Arch. Ration. Mech. Anal. 233 (2019), 167–247) via an energetic variational approach and it naturally fulfils three physical constraints such as mass conservation, energy dissipation and force balance. The target problem examined in this paper can be viewed as a transmission problem that consists of Cahn–Hilliard type equations both in the bulk and on the boundary. In our approach, we are able to deal with a general class of potentials with double-well structure, including the physically relevant logarithmic potential and the non-smooth double-obstacle potential. Existence, uniqueness and continuous dependence of global weak solutions are established. The proof is based on a novel time-discretization scheme for the approximation of the continuous problem. Besides, a regularity result is shown with the aim of obtaining a strong solution to the system
H. & P. Sauermann A.-G., Kulmbach-München, Tafel-Schinken
No full textH. & P. SAUERMANN A.-G., KULMBACH-MÜNCHEN, TAFEL-SCHINKEN
H. & P. Sauermann A.-G., Kulmbach-München, Tafel-Schinken ( -
Functorial Decompositions of Looped Coassociative Co-<i>H</i> Spaces
No full textAbstractSelick and Wu gave a functorial decomposition of Ω∑X for path-connected, p-local CW-complexes X which obtained the smallest nontrivial functorial retract Amin(X) of Ω∑X. This paper uses methods developed by the second author in order to extend such functorial decompositions to the loops on coassociative co-H spaces.</jats:p
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Rank p ? 1 mod-p H-spaces
No full textDifferent constructions by Cooke, Harper and Zabrodsky and by Cohen and Neisendorfer produce torsion free finite p-local H-spaces of rank l < p ? 1. The first construction goes through when l = p ? 1 and we show the second does as well. However, the space produced need not be an H-space. We give a criterion for when an H-space is obtained. In the special case of rank 2 mod-3 H-spaces, we also give a practical test for when the criterion holds, and use this to give many new examples of finite H-spaces
Search for new hadronic decays of h c and observation of h c → p p ¯ η
No full textAbstract A search for the hadronic decays of the h c meson to the final states p p ¯ π + π − π 0, p p ¯ η , and p p ¯ π 0 via the process ψ(3686) → π 0 h c is performed using (4.48 ± 0.03) × 108 ψ(3686) events collected with the BESIII detector. The decay channel h c → p p ¯ η is observed for the first time with a significance greater than 5σ and a branching fraction of (6.41 ± 1.74 ± 0.53 ± 1.00) × 10 −4, where the uncertainties are statistical, systematic, and that from the branching fraction of ψ(3686) → π 0 h c . Strong evidence for the decay h c → p p ¯ π + π − π 0 is found with a significance of 4.9σ and a branching fraction of (3.84 ± 0.83 ± 0.69 ± 0.58) × 10 −3. The significances include systematic uncertainties. No clear signal of the decay h c → p p ¯ π 0 is found, and an upper limit of 6.59 × 10 −4 on its branching fraction is set at the 90% confidence level
Modular representations and the homotopy of low rank p-local CW-complexes
No full textFix an odd prime p and let X be the p-localization of a finite suspended CW-complex. Given certain conditions on the reduced mod-p homology H˜?(X;Zp) of X, we use a decomposition of ??X due to the second author and computations in modular representation theory to show there are arbitrarily large integers i such that ?? i X is a homotopy retract of ??X. This implies the stable homotopy groups of ?X are in a certain sense retracts of the unstable homotopy groups, and by a result of Stanley, one can confirm the Moore conjecture for ?X. Under additional assumptions on H˜?(X;Zp), we generalize a result of Cohen and Neisendorfer to produce a homotopy decomposition of ??X that has infinitely many finite H-spaces as factors
H. & P. Sauermann A.-G. Kulmbach-München. Aus dem Hofbräuhaus, »Do tat mir d’Wahl weh!«
No full textH. & P. SAUERMANN A.-G. KULMBACH-MÜNCHEN. AUS DEM HOFBRÄUHAUS, »DO TAT MIR D’WAHL WEH!«
H. & P. Sauermann A.-G. Kulmbach-München. Aus dem Hofbräuhaus, »Do tat mir d’Wahl weh!« ( -
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