85,147 research outputs found
A design of a strongly stable generalized predictive control using coprime factorization approach
This paper proposes a new generalized predictive control (GPC) having new design parameters. In selecting the design parameters, the controller becomes a strongly stable GPC, that is, not only the closed-loop system is stable, but also the controller itself is stable. The parameters are introduced by applying the coprime factorization approach and comparing Youla parametrization of stabilizing compensators to the controller by the standard GPC</p
Numerical simulations studies of the convective instability onset in a supercritical fluid
Numerical simulation studies in 2D with the addition of noise are reported
for the convection of a supercritical fluid,3He, in a Rayleigh-Be'nard cell
where the fluid parameters and cell height L are the same as in published
laboratory experiments. The noise addition is to accelerate the instability
onset after starting the heat flow across the fluid, so as to bring simulations
into better agreement with experimental observations. Homogeneous temperature
noise and spatial lateral periodic temperature variations in the top plate were
programmed into the simulations. A speed-up in the instability onset was
obtained, which was most effective through the spatial temperature variations
with a period of 2L, close to the wavelength of a pair of convections rolls.
For a small amplitude of 0.5 microK, this perturbation gave a semiquantitative
agreement with experimental observations. Results for various noise amplitudes
are presented and discussed in relation to predictions by El Khouri and
Carle`s.Comment: 6 pages (2-column format) 4 figures, Proceedings of NASA2004
workshop, Solvang,C
Weyl law for open systems with sharply divided mixed phase space
A generalization of the Weyl law to systems with a sharply divided mixed
phase space is proposed. The ansatz is composed of the usual Weyl term which
counts the number of states in regular islands and a term associated with
sticky regions in phase space. For a piecewise linear map, we numerically check
the validity of our hypothesis, and find good agreement not only for the case
with a sharply divided phase space, but also for the case where tiny island
chains surround the main regular island. For the latter case, a non-trivial
power law exponent appears in the survival probability of classical escaping
orbits, which may provide a clue to develop the Weyl law for more generic mixed
systems.Comment: 8 pages, 14 figure
A Fundamental Limit of Measurement Imposed by the Elementary Interactions
Quantum information theory is closely related to quantum measurement theory
because one must perform measurement to obtain information on a quantum system.
Among many possible limits of quantum measurement, the simplest ones were
derived directly from the uncertainty principles. However, such simple limits
are not the only limits. I here suggest a new limit which comes from the forms
and the strengths of the elementary interactions. Namely, there are only four
types of elementary interactions in nature; their forms are determined by the
gauge invariance (and symmetry breaking), and their coupling constants (in the
low-energy regime) have definite values. I point out that this leads to a new
fundamental limit of quantum measurements. Furthermore, this fundamental limit
imposes the fundamental limits of getting information on, preparing, and
controlling quantum systems.Comment: 10 pages including 1 figure. Proc. 3rd Tohwa Univ. Int. Conf.
Statistical Physics (Fukuoka, Japan, 1999) to be published from AI
Approaches to QCD phase diagram; effective models, strong-coupling lattice QCD, and compact stars
The outline of the two lectures given in "Dense Matter School 2015" is
presented. After an overview on the relevance of the phase diagram to heavy-ion
collisions and compact star phenomena, I show some basic formulae to discuss
the QCD phase diagram in the mean field treatment of the Nambu-Jona-Lasinio
model. Next, I introduce the strong-coupling lattice QCD, which is one of the
promising methods to access the QCD phase diagram including the first order
phase boundary. In the last part, I discuss the QCD phase diagram in asymmetric
matter, which should be formed in compact star phenomena.Comment: Lecture given at Helmholtz International Summer School "Dense Matter
2015", 29 June-11 July 2015 and the 15th International Conference on
Strageness in Quark Matter (SQM 2015), 6-11 July 2015, Dubna, Russia. 12
pages, 10 figures. Some typos are corrected in v
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