444 research outputs found
An infeasible interior-point arc-search method with Nesterov's restarting strategy for linear programming problems
An arc-search interior-point method is a type of interior-point methods that
approximates the central path by an ellipsoidal arc, and it can often reduce
the number of iterations. In this work, to further reduce the number of
iterations and computation time for solving linear programming problems, we
propose two arc-search interior-point methods using Nesterov's restarting
strategy that is well-known method to accelerate the gradient method with a
momentum term. The first one generates a sequence of iterations in the
neighborhood, and we prove that the convergence of the generated sequence to an
optimal solution and the computation complexity is polynomial time. The second
one incorporates the concept of the Mehrotra-type interior-point method to
improve numerical performance. The numerical experiments demonstrate that the
second one reduced the number of iterations and computational time. In
particular, the average number of iterations was reduced compared to existing
interior-point methods due to the momentum term.Comment: 33 pages, 6 figures, 2 table
Lattice-QCD based Schwinger-Dyson approach for Chiral Phase Transition
Dynamical chiral-symmetry breaking in QCD is studied with the Schwinger-Dyson
(SD) formalism based on lattice QCD data, i.e., LQCD-based SD formalism. We
extract the SD kernel function in an Ansatz-independent manner from
the lattice data of the quark propagator in the Landau gauge. As remarkable
features, we find infrared vanishing and intermediate enhancement of the SD
kernel function . We apply the LQCD-based SD equation to thermal QCD
with the quark chemical potential . We find chiral symmetry restoration
at for . The real part of the quark mass
function decreases as and . At finite density, there appears the
imaginary part of the quark mass function, which would lead to the width
broadening of hadrons.Comment: 4 pages, 4 figures, Presented at Workshop on QCD Down Under, Barossa
Valley and Adelaide, Australia, 10-19 Mar 200
Characterization of Tunable Magnetic Sensor Using Bias Magnetic Field of a Hard Magnetic Film Magnetized by Pulsed-Magnetic Field
A tunable magnetoresistance (MR) sensor with variable sensitivity and measuring range is fabricated and characterized. The sensor has been fabricated using a combination of Ni-Fe soft magnetic film, Fe-Co-Sm hard magnetic film. The sensor is placed in a magnetizing coil for the process of magnetizing the hard magnetic film. The sensitivity and the measuring range of the sensor are tuned by bias magnetic field produced by the magnetic poles of the hard magnetic film. The sensitivity change was about 60%, and the measuring range change was about 30% in the tunable MR sensor from the experimental results. The bias magnetic field is controlled by changing amplitude of the pulsed magnetic field in the magnetizing for the hard magnetic film. The control power for one time tuning is about 18 mu Wh.ArticleIEEE TRANSACTIONS ON MAGNETICS. 49(7):3854-3857 (2013)journal articl
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