776 research outputs found
Large-N mesons
We present an update of our project of computing the meson spectrum and decay
constants in large-N QCD. The results are obtained in the quenched
approximation with the Wilson fermion action for N = 2, 3, 4, 5, 6, 7 and 17
and extrapolated to infinite N. We non-perturbatively determine the
renormalization factors for local quark bilinears that are needed to compute
the decay constants. We extrapolate our SU(7) results to the continuum limit,
employing four different lattice spacings.Comment: 7 pages, 4 figures, presented at the 31st International Symposium on
Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, German
Separation of Cultivars of Soybeans by Chemometric Methods Using Near Infrared Spectroscopy.
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The meson spectrum in large-N QCD
We present lattice results on the meson spectrum and decay constants in large-N QCD. The results are obtained in the quenched approximation for N = 2,3,4,5,6,7 and 17 and extrapolated to N = ∞. Xth Quark Confinement and the Hadron Spectrum
Finite-size effects on a lattice calculation
We study in this paper the finite-size effects of a non-periodic lattice on a
lattice calculation. To this end we use a finite lattice equipped with a
central difference derivative with homogeneous boundary conditions to calculate
the bosonic mass associated to the Schwinger model. We found that the
homogeneous boundary conditions produce absence of fermion doubling and chiral
invariance, but we also found that in the continuum limit this lattice model
does not yield the correct value of the boson mass as other models do. We
discuss the reasons for this and, as a result, the matrix which cause the
fermion doubling problem is identified.Comment: 8 pages, no figures, extended version, five references adde
Shear and bulk viscosities for pure glue matter
Shear and bulk viscosities are calculated in a quasiparticle
model within a relaxation time approximation for pure gluon matter. Below
the confined sector is described within a quasiparticle glueball model.
Particular attention is paid to behavior of the shear and bulk viscosities near
. The constructed equation of state reproduces the first-order phase
transition for the glue matter. It is shown that with this equation of state it
is possible to describe the temperature dependence of the shear viscosity to
entropy ratio and the bulk viscosity to entropy ratio in
reasonable agreement with available lattice data but absolute values of the
ratio underestimate the upper limits of this ratio in the lattice
measurements typically by an order of magnitude.Comment: 8 pages, 4 figures; the published versio
Kinematic and dynamic assessment of trunk exoskeleton
In Industry 4.0, wearable exoskeletons have been proposed as collaborative robotic devices to partially assist workers in heavy and dangerous tasks. Despite the recent researches, proposed prototypes and commercial products, some open issues concerning development, improvements and testing still exist. The current pilot study proposed the assessment of a proper biomechanical investigation of passive trunk exoskeleton effects on the human body. One healthy subject performed walking, stoop and semisquat tasks without, with exoskeleton no support and with exoskeleton with support. 3D Kinematic (angles, translations) and dynamic (interface forces) parameters of both human and exoskeleton were estimated. Some differences were pointed out comparing task motions and exoskeleton conditions. The presented preliminary test revealed interesting results in terms of different human joints coordination, interface forces exchanged at contact points and possible misalignment between human and device. The present study could be considered as a starting point for the investigation of exoskeleton effectiveness and interaction with the user
Optimal disclosure risk assessment
Protection against disclosure is a legal and ethical obligation for agencies releasing microdata les for public use. Consider a microdata sample of size n from a nite population of size n = n + n, with > 0, such that each sample record contains two disjoint types of information: identifying categorical information and sensitive information. Any decision about releasing data is supported by the estimation of measures of disclosure risk, which are dened as discrete functionals of the number of sample records with a unique combination of values of identifying variables. The most common measure is arguably the number 1 of sample unique records that are population uniques. In this paper, we rst study nonparametric estimation of 1 under the Poisson abundance model for sample records. We introduce a class of linear estimators of 1 that are simple, computationally ecient and scalable to massive datasets, and we give uniform theoretical guarantees for them. In particular, we show that they provably estimate 1 all of the way up to the sampling fraction ( + 1)1 / (log n)1, with vanishing normalized mean-square error (NMSE) for large n. We then establish a lower bound for the minimax NMSE for the estimation of 1, which allows us to show that: i) (+1)1 / (log n)1 is the smallest possible sampling fraction for consistently estimating 1; ii) estimators' NMSE is near optimal, in the sense of matching the minimax lower bound, for large n. This is the main result of our paper, and it provides a rigorous answer to an open question about the feasibility of nonparametric estimation of 1 under the Poisson abundance model and for a sampling fraction ( + 1)1 < 1=2
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