7,242 research outputs found
Deep Learning and Music Adversaries
OA Monitor ExerciseOA Monitor ExerciseAn {\em adversary} is essentially an algorithm intent on making a classification system perform in some particular way given an input, e.g., increase the probability of a false negative. Recent work builds adversaries for deep learning systems applied to image object recognition, which exploits the parameters of the system to find the minimal perturbation of the input image such that the network misclassifies it with high confidence. We adapt this approach to construct and deploy an adversary of deep learning systems applied to music content analysis. In our case, however, the input to the systems is magnitude spectral frames, which requires special care in order to produce valid input audio signals from network-derived perturbations. For two different train-test partitionings of two benchmark datasets, and two different deep architectures, we find that this adversary is very effective in defeating the resulting systems. We find the convolutional networks are more robust, however, compared with systems based on a majority vote over individually classified audio frames. Furthermore, we integrate the adversary into the training of new deep systems, but do not find that this improves their resilience against the same adversary
Two-Loop Virtual Corrections to Drell-Yan Production at order alpha_s alpha^3
The Drell-Yan mechanism for the production of lepton pairs is one of the most
basic processes for physics studies at hadron colliders. It is therefore
important to have accurate theoretical predictions. In this work we compute the
two-loop virtual mixed QCD x QED corrections to Drell-Yan production. We
evaluate the Feynman diagrams by decomposing the amplitudes into a set of known
master integrals and their coefficients, which allows us to derive an
analytical result. We also perform a detailed study of the ultraviolet and
infrared structure of the two-loop amplitude and the corresponding poles in
epsilon.Comment: 20 pages, 3 figure
Two-Loop Threshold Singularities, Unstable Particles and Complex Masses
The effect of threshold singularities induced by unstable particles on
two-loop observables is investigated and it is shown how to cure them working
in the complex-mass scheme. The impact on radiative corrections around
thresholds is thoroughly analyzed and shown to be relevant for two selected LHC
and ILC applications: Higgs production via gluon fusion and decay into two
photons at two loops in the Standard Model. Concerning Higgs production, it is
essential to understand possible sources of large corrections in addition to
the well-known QCD effects. It is shown that NLO electroweak corrections can
incongruently reach a 10 % level around the WW vector-boson threshold without a
complete implementation of the complex-mass scheme in the two-loop calculation.Comment: LaTeX, 12 pages, 7 figure
NNLO Computational Techniques: the Cases H -> gamma gamma and H -> g g
A large set of techniques needed to compute decay rates at the two-loop level
are derived and systematized. The main emphasis of the paper is on the two
Standard Model decays H -> gamma gamma and H -> g g. The techniques, however,
have a much wider range of application: they give practical examples of general
rules for two-loop renormalization; they introduce simple recipes for handling
internal unstable particles in two-loop processes; they illustrate simple
procedures for the extraction of collinear logarithms from the amplitude. The
latter is particularly relevant to show cancellations, e.g. cancellation of
collinear divergencies. Furthermore, the paper deals with the proper treatment
of non-enhanced two-loop QCD and electroweak contributions to different
physical (pseudo-)observables, showing how they can be transformed in a way
that allows for a stable numerical integration. Numerical results for the
two-loop percentage corrections to H -> gamma gamma, g g are presented and
discussed. When applied to the process pp -> gg + X -> H + X, the results show
that the electroweak scaling factor for the cross section is between -4 % and +
6 % in the range 100 GeV < Mh < 500 GeV, without incongruent large effects
around the physical electroweak thresholds, thereby showing that only a
complete implementation of the computational scheme keeps two-loop corrections
under control.Comment: LaTeX, 70 pages, 8 eps figure
Mrk 1014: An AGN Dominated ULIRG at X-rays
In this paper we report on an XMM-Newton observation of the ultraluminous
infrared QSO Mrk 1014. The X-ray observation reveals a power-law dominated
(photon index of about 2.2) spectrum with a slight excess in the soft energy
range. AGN and starburst emission models fit the soft excess emission equally
well, however, the most plausible explanation is an AGN component as the
starburst model parameter, temperature and luminosity, appear physically
unrealistic. The mean luminosity of Mrk 1014 is about 2 times 10^44 erg s^-1.
We have also observed excess emission at energies greater than 5 keV. This
feature could be attributed to a broadened and redshifted iron complex, but
deeper observations are required to constrain its origin. The light curve shows
small scale variability over the 11 ks observation. There is no evidence of
intrinsic absorption in Mrk 1014. The X-ray observations support the notion of
an AGN dominated central engine. We establish the need for a longer observation
to constrain more precisely the nature of the X-ray components.Comment: 5 pages incl. 3 figures, MNRAS in pres
Multi-wavelength properties of IGR J05007-7047 (LXP 38.55) and identification as a Be X-ray binary pulsar in the LMC
We report on the results of a 40 d multi-wavelength monitoring of the
Be X-ray binary system IGR J05007-7047 (LXP 38.55). During that period the
system was monitored in the X-rays using the Swift telescope and in the optical
with multiple instruments. When the X-ray luminosity exceeded erg/s
we triggered an XMM-Newton ToO observation. Timing analysis of the photon
events collected during the XMM-Newton observation reveals coherent X-ray
pulsations with a period of 38.551(3) s (1 {\sigma}), making it the 17
known high-mass X-ray binary pulsar in the LMC. During the outburst, the X-ray
spectrum is fitted best with a model composed of an absorbed power law () plus a high-temperature black-body (kT 2 keV) component. By
analysing 12 yr of available OGLE optical data we derived a 30.776(5) d
optical period, confirming the previously reported X-ray period of the system
as its orbital period. During our X-ray monitoring the system showed limited
optical variability while its IR flux varied in phase with the X-ray
luminosity, which implies the presence of a disk-like component adding cooler
light to the spectral energy distribution of the system.Comment: 11 pages, 11 figures, Accepted for publication in MNRA
Analysis, Visualization, and Transformation of Audio Signals Using Dictionary-based Methods
date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +0000date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +000
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