10,368 research outputs found
Taste symmetry breaking with HYP-smeared staggered fermions
We study the impact of hypercubic (HYP) smearing on the size of taste
breaking for staggered fermions, comparing to unimproved and to asqtad-improved
staggered fermions. As in previous studies, we find a substantial reduction in
taste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on
lattices with spacing fm). In addition, we observe that
discretization effects of next-to-leading order in the chiral expansion () are markedly reduced by HYP smearing. Compared to asqtad valence
fermions, we find that taste-breaking in the pion spectrum is reduced by a
factor of 2.5-3, down to a level comparable to the expected size of generic
effects. Our results suggest that, once one reaches a lattice
spacing of fm, taste-breaking will be small enough after HYP
smearing that one can use a modified power counting in which , simplify fitting to phenomenologically interesting quantities.Comment: 14 pages, 13 figures, references updated, minor change
Applicability valuation for evaluation of surface deflection in automotive outer panels
Upon unloading in a forming process there is elastic recovery, which is the release of the elastic strains and the redistribution of the residual stresses through the thickness direction, thus producing surface deflection. It causes changes in shape and dimensions that can create major problem in the external appearance of outer panels. Thus surface deflection prediction is an important issue in sheet metal forming industry. Many factors could affect surface deflection in the process, such as material variations in mechanical properties, sheet thickness, tool geometry, processing parameters and lubricant condition. The shape and dimension problem in press forming is defined as a trouble mainly caused by the elastic recovery of materials during the forming. The use of high strength steel sheets in the manufacturing of automobile outer panels has increased in the automotive industry over the years because of its lightweight and fuel-efficient improvement. But one of the major concerns of stamping is surface deflection in the formed outer panels. Hence, to be cost effective, accurate prediction must be made of its formability. The automotive industry places rigi
Efficient range alignment algorithm for real-time range-Doppler algorithm
When deriving a range-Doppler image or a time-frequency image of a fast-maneuvering target at long range, existing range alignment methods yield poor results due to the large numbers of range profiles (RPs) and range bins that are required for this task. This paper proposes a three-step range alignment method to overcome the problems of these existing methods and to yield focused images: (1) coarse alignment using the interpolated center of mass of each RP, (2) fine alignment with an integer step using an entropy cost function, and (3) fine-tuning using particle swarm optimization. Compared to existing methods, the proposed method is computationally more efficient and provides better image focus. © 2017, Electromagnetics Academy. All rights reserved.11Yscopu
Using Hierarchical Data Mining to Characterize Performance of Wireless System Configurations
This paper presents a statistical framework for assessing wireless systems
performance using hierarchical data mining techniques. We consider WCDMA
(wideband code division multiple access) systems with two-branch STTD (space
time transmit diversity) and 1/2 rate convolutional coding (forward error
correction codes). Monte Carlo simulation estimates the bit error probability
(BEP) of the system across a wide range of signal-to-noise ratios (SNRs). A
performance database of simulation runs is collected over a targeted space of
system configurations. This database is then mined to obtain regions of the
configuration space that exhibit acceptable average performance. The shape of
the mined regions illustrates the joint influence of configuration parameters
on system performance. The role of data mining in this application is to
provide explainable and statistically valid design conclusions. The research
issue is to define statistically meaningful aggregation of data in a manner
that permits efficient and effective data mining algorithms. We achieve a good
compromise between these goals and help establish the applicability of data
mining for characterizing wireless systems performance
BSML: A Binding Schema Markup Language for Data Interchange in Problem Solving Environments (PSEs)
We describe a binding schema markup language (BSML) for describing data
interchange between scientific codes. Such a facility is an important
constituent of scientific problem solving environments (PSEs). BSML is designed
to integrate with a PSE or application composition system that views model
specification and execution as a problem of managing semistructured data. The
data interchange problem is addressed by three techniques for processing
semistructured data: validation, binding, and conversion. We present BSML and
describe its application to a PSE for wireless communications system design
Radion Dynamics and Phenomenology in the Linear Dilaton Model
We investigate the properties of the radion in the 5D linear dilaton model
arising from Little String Theory. A Goldberger-Wise type mechanism is used to
stabilise a large interbrane distance, with the dilaton now playing the role of
the stabilising field. We consider the coupled fluctuations of the metric and
dilaton fields and identify the physical scalar modes of the system. The
wavefunctions and masses of the radion and Kaluza-Klein modes are calculated,
giving a radion mass of order the curvature scale. As a result of the direct
coupling between the dilaton and Standard Model fields, the radion couples to
the SM Lagrangian, in addition to the trace of the energy-momentum tensor. The
effect of these additional interaction terms on the radion decay modes is
investigated, with a notable increase in the branching fraction to photons. We
also consider the effects of a non-minimal Higgs coupling to gravity, which
introduces a mixing between the Higgs and radion modes. Finally, we calculate
the production cross section of the radion at the LHC and use the current Higgs
searches to place constraints on the parameter space.Comment: 28 pages, 7 figures; v2: error in radion-gauge boson Feynman rules
corrected, version published in JHE
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