29,828 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
A dynamical and kinematical model of the Galactic stellar halo and possible implications for galaxy formation scenarios
We re-analyse the kinematics of the system of blue horizontal branch field
(BHBF) stars in the Galactic halo (in particular the outer halo), fitting the
kinematics with the model of radial and tangential velocity dispersions in the
halo as a function of galactocentric distance r proposed by Sommer-Larsen,
Flynn & Christensen (1994), using a much larger sample (almost 700) of BHBF
stars. The basic result is that the character of the stellar halo velocity
ellipsoid changes markedly from radial anisotropy at the sun to tangential
anisotropy in the outer parts of the Galactic halo (r greater than approx 20
kpc). Specifically, the radial component of the stellar halo's velocity
ellipsoid decreases fairly rapidly beyond the solar circle, from approx 140 +/-
10 km/s at the sun, to an asymptotic value of 89 +/- 19 km/s at large r. The
rapid decrease in the radial velocity dispersion is matched by an increase in
the tangential velocity dispersion, with increasing r.
Our results may indicate that the Galaxy formed hierarchically (partly or
fully) through merging of smaller subsystems - the 'bottom-up' galaxy formation
scenario, which for quite a while has been favoured by most theorists and
recently also has been given some observational credibility by HST observations
of a potential group of small galaxies, at high redshift, possibly in the
process of merging to a larger galaxy (Pascarelle et al 1996).Comment: Latex, 16 pages. 2 postscript figures. Submitted to the Astrophysical
Journal. also available at http://astro.utu.fi/~cflynn/outerhalo.htm
Low-energy enhancement of magnetic dipole radiation
Magnetic dipole strength functions have been deduced from averages of a large
number of transition strengths calculated within the shell model for the
nuclides Zr, Mo, Mo, and Mo. An enhancement of
strength toward low transition energy has been found for all nuclides
considered. Large strengths appear for transitions between close-lying
states with configurations including proton as well as neutron high- orbits
that re-couple their spins and add up their magnetic moments coherently. The
strength function deduced from the calculated transition strengths is
compatible with the low-energy enhancement found in (He,He') and
experiments. The present work presents for the first time an
explanation of the experimental findings
The N-eigenvalue Problem and Two Applications
We consider the classification problem for compact Lie groups
which are generated by a single conjugacy class with a fixed number of
distinct eigenvalues. We give an explicit classification when N=3, and apply
this to extract information about Galois representations and braid group
representations.Comment: 30 pages. version 3: many typos fixed, section 6 substantially
reorganized. To appear in Int. Math. Res. No
The Development of Polyamines throughout Brassica rapa over its Lifecycle
Polyamines are naturally produced chemicals in plants involved in growth, development and stress response. The primary objective of my study is to create a profile of changes in the entire life of the plant, in every organ at all stages of development from seed germination to seed formation. We have analyzed polyamines putrescine, spermidine and spermine in all parts of Brassica rapa, a small, rapid growing plant. Parallel to the polyamines, we will also study changes in the activities of the polyamine biosynthetic enzymes and the expression of their genes in different organs at different times. In the next stage of the study, the expression of selected genes will be inhibited by RNAi constructs, allowing further analysis of their role in growth and stress response. Because polyamines play are important in development and lifecycle of plants, altering their presence may be useful in altering plant growth patterns, such as in seasonal crops
Theoretical study of production of unique glasses in space
The potential of producing the glassy form of selected materials in the weightless, containerless nature of space processing is examined through the development of kinetic relationships describing nucleation and crystallization phenomena. Transformation kinetics are applied to a well-characterized system (SiO2), an excellent glass former (B2O3), and a poor glass former (Al2O3) by conventional earth processing methods. Viscosity and entropy of fusion are shown to be the primary materials parameters controlling the glass forming tendency. For multicomponent systems diffusion-controlled kinetics and heterogeneous nucleation effects are considered. An analytical empirical approach is used to analyze the mullite system. Results are consistent with experimentally observed data and indicate the promise of mullite as a future space processing candidate
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