16,686 research outputs found
Generalized Lomb-Scargle analysis of decay rate measurements from the Physikalisch-Technische Bundesanstalt
We apply the generalized Lomb-Scargle (LS) periodogram to independently
confirm the claim by Sturrock et al (arXiv:1605.03088) of oscillation at a
frequency of 11/year in the decay rates of from
measurements at the Physikalisch Technische Bundesanstalt (PTB), which however
has been disputed by Kossert and Nahle (arXiv:1407.2493). For this analysis, we
made two different {\it ansatze} for the errors. For each peak in the LS
periodogram, we evaluate the statistical significance using non-parametric
bootstrap resampling. We find using both of these error models evidence for
~11/year periodicity in the data for two of the three
samples, but at a lower significance than that claimed by Sturrock et al.Comment: 9 pages, 9 figure
Autonomous navigation for artificial satellites
An autonomous navigation system is considered that provides a satellite with sufficient numbers and types of sensors, as well as computational hardware and software, to enable it to track itself. Considered are attitude type sensors, meteorological cameras and scanners, one way Doppler, and image correlator
Magnetoresistance in organic light-emitting diode structures under illumination
Copyright 2007 by the American Physical Society. Article is available at
Magnetoresistance in triphenyl-diamine derivative blue organic light emitting devices
Copyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 103, 043706 (2008) and may be found at
The role of magnetic fields on the transport and efficiency of aluminum tris(8-hydroxyquinoline) based organic light emitting diodes
Copyright 2007 AIP Publishing LLC. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Journal of Applied Physics [102, 073710 (2007)] and may be found at
Optimization of Discrete-parameter Multiprocessor Systems using a Novel Ergodic Interpolation Technique
Modern multi-core systems have a large number of design parameters, most of
which are discrete-valued, and this number is likely to keep increasing as chip
complexity rises. Further, the accurate evaluation of a potential design choice
is computationally expensive because it requires detailed cycle-accurate system
simulation. If the discrete parameter space can be embedded into a larger
continuous parameter space, then continuous space techniques can, in principle,
be applied to the system optimization problem. Such continuous space techniques
often scale well with the number of parameters.
We propose a novel technique for embedding the discrete parameter space into
an extended continuous space so that continuous space techniques can be applied
to the embedded problem using cycle accurate simulation for evaluating the
objective function. This embedding is implemented using simulation-based
ergodic interpolation, which, unlike spatial interpolation, produces the
interpolated value within a single simulation run irrespective of the number of
parameters. We have implemented this interpolation scheme in a cycle-based
system simulator. In a characterization study, we observe that the interpolated
performance curves are continuous, piece-wise smooth, and have low statistical
error. We use the ergodic interpolation-based approach to solve a large
multi-core design optimization problem with 31 design parameters. Our results
indicate that continuous space optimization using ergodic interpolation-based
embedding can be a viable approach for large multi-core design optimization
problems.Comment: A short version of this paper will be published in the proceedings of
IEEE MASCOTS 2015 conferenc
Signals of supersymmetry with inaccessible first two families at the Large Hadron Collider
We investigate the signals of supersymmetry (SUSY) in a scenario where only
the third family squarks and sleptons can be produced at the Large Hadron
Collider (LHC), in addition to the gluino, charginos and neutralinos. The final
states in such cases are marked by a multiplicity of top and/or bottom quarks.
We study in particular, the case when the stop, sbottom and gluino masses are
near the TeV scale due to which, the final state t's and b's are very
energetic. We point out the difficulty in b-tagging and identifying energetic
tops and suggest several event selection criteria which allow the signals to
remain significantly above the standard model background. We show that such
scenarios with gluino mass up to 2 TeV can be successfully probed at the LHC.
Information on can also be obtained by looking at associated Higgs
production in the cascades of accompanying neutralinos. We also show that a
combined analysis of event rates in the different channels and the effective
mass distribution allows one to differentiate this scenario from the one where
all three sfermion families are accessible.Comment: v3: 17 pages, 8 figures, 7 table
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