5,445 research outputs found
Fashion Conversation Data on Instagram
The fashion industry is establishing its presence on a number of
visual-centric social media like Instagram. This creates an interesting clash
as fashion brands that have traditionally practiced highly creative and
editorialized image marketing now have to engage with people on the platform
that epitomizes impromptu, realtime conversation. What kinds of fashion images
do brands and individuals share and what are the types of visual features that
attract likes and comments? In this research, we take both quantitative and
qualitative approaches to answer these questions. We analyze visual features of
fashion posts first via manual tagging and then via training on convolutional
neural networks. The classified images were examined across four types of
fashion brands: mega couture, small couture, designers, and high street. We
find that while product-only images make up the majority of fashion
conversation in terms of volume, body snaps and face images that portray
fashion items more naturally tend to receive a larger number of likes and
comments by the audience. Our findings bring insights into building an
automated tool for classifying or generating influential fashion information.
We make our novel dataset of {24,752} labeled images on fashion conversations,
containing visual and textual cues, available for the research community.Comment: 10 pages, 6 figures, This paper will be presented at ICWSM'1
SciRecSys: A Recommendation System for Scientific Publication by Discovering Keyword Relationships
In this work, we propose a new approach for discovering various relationships
among keywords over the scientific publications based on a Markov Chain model.
It is an important problem since keywords are the basic elements for
representing abstract objects such as documents, user profiles, topics and many
things else. Our model is very effective since it combines four important
factors in scientific publications: content, publicity, impact and randomness.
Particularly, a recommendation system (called SciRecSys) has been presented to
support users to efficiently find out relevant articles
Localized ferromagnetic resonance force microscopy in permalloy-cobalt films
We report Ferromagnetic Resonance Force Microscopy (FMRFM) experiments on a
justaposed continuous films of permalloy and cobalt. Our studies demonstrate
the capability of FMRFM to perform local spectroscopy of different
ferromagnetic materials. Theoretical analysis of the uniform resonance mode
near the edge of the film agrees quantitatively with experimental data. Our
experiments demonstrate the micron scale lateral resolution in determining
local magnetic properties in continuous ferromagnetic samples.Comment: 7 pages, 3 figure
Characteristic molecular properties of one-electron double quantum rings under magnetic fields
The molecular states of conduction electrons in laterally coupled quantum
rings are investigated theoretically. The states are shown to have a distinct
magnetic field dependence, which gives rise to periodic fluctuations of the
tunnel splitting and ring angular momentum in the vicinity of the ground state
crossings. The origin of these effects can be traced back to the Aharonov-Bohm
oscillations of the energy levels, along with the quantum mechanical tunneling
between the rings. We propose a setup using double quantum rings which shows
that Aharonov-Bohm effects can be observed even if the net magnetic flux
trapped by the carriers is zero.Comment: 16 pages (iopart format), 10 figures, accepted in J.Phys.Cond.Mat
The Distance to the Vela Supernova Remnant
We have obtained high resolution Ca II and Na I absorption line spectra
toward 68 OB stars in the direction of the Vela Supernova Remnant. The stars
lie at distances of 190 -- 2800 pc as determined by Hipparcos and spectroscopic
parallax estimations. The presence of high velocity absorption attributable to
the remnant along some of the sight lines constrains the remnant distance to
250+/-30 pc. This distance is consistent with several recent investigations
that suggest that the canonical remnant distance of 500 pc is too large.Comment: To be published in The Astrophysical Journal Letters Figure 1 y-axis
labels correcte
Modeling of the Vela complex including the Vela supernova remnant, the binary system gamma2 Velorum, and the Gum nebula
We study the geometry and dynamics of the Vela complex including the Vela
supernova remnant (SNR), the binary system gamma2 Velorum and the Gum nebula.
We show that the Vela SNR belongs to a subclass of non-Sedov adiabatic remnants
in a cloudy interstellar medium (ISM), the dynamics of which is determined by
the heating and evaporation of ISM clouds. We explain observable
characteristics of the Vela SNR with a SN explosion with energy 1.4 x 10^50
ergs near the step-like boundary of the ISM with low intercloud densities (~
10^{-3} cm^{-3}) and with a volume-averaged density of clouds evaporated by
shock in the north-east (NE) part about four times higher than the one in the
south-west (SW) part. The observed asymmetry between the NE and SW parts of the
Vela SNR could be explained by the presence of a stellar wind bubble (SWB)
blown by the nearest-to-the Earth Wolf-Rayet (WR) star in the gamma2 Velorum
system. We show that the size and kinematics of gamma2 Velorum SWB agree with
predictions of numerical calculations for the evolution of the SWB of M_ini =
35M* star. The low initial mass of the WR star in gamma2 Velorum implies that
the luminosity of the nuclear line of 26Al, produced by gamma2 Velorum, is
below the sensitivity of existing gamma-ray telescopes.Comment: 8 pages, 2 figures, accepted for publication in A&
New model for system of mesoscopic Josephson contacts
Quantum fluctuations of the phases of the order parameter in 2D arrays of
mesoscopic Josephson junctions and their effect on the destruction of
superconductivity in the system are investigated by means of a quantum-cosine
model that is free of the incorrect application of the phase operator. The
proposed model employs trigonometric phase operators and makes it possible to
study arrays of small superconducting granules, pores filled with superfluid
helium, or Josephson junctions in which the average number of particles
(effective bosons, He atoms, and so on) is small, and the standard approach
employing the phase operator and the particle number operator as conjugate ones
is inapplicable. There is a large difference in the phase diagrams between
arrays of macroscopic and mesoscopic objects for and ( is
the characteristic interaction energy of the particle per granule and is
the Josephson coupling constant). Reentrant superconductivity phenomena are
discussed.Comment: 4 pages, 3 Postscript figure
SPHS: Smoothed Particle Hydrodynamics with a higher order dissipation switch
We present a novel implementation of Smoothed Particle Hydrodynamics (SPHS)
that uses the spatial derivative of the velocity divergence as a higher order
dissipation switch. Our switch -- which is second order accurate -- detects
flow convergence before it occurs. If particle trajectories are going to cross,
we switch on the usual SPH artificial viscosity, as well as conservative
dissipation in all advected fluid quantities (for example, the entropy). The
viscosity and dissipation terms (that are numerical errors) are designed to
ensure that all fluid quantities remain single-valued as particles approach one
another, to respect conservation laws, and to vanish on a given physical scale
as the resolution is increased. SPHS alleviates a number of known problems with
`classic' SPH, successfully resolving mixing, and recovering numerical
convergence with increasing resolution. An additional key advantage is that --
treating the particle mass similarly to the entropy -- we are able to use
multimass particles, giving significantly improved control over the refinement
strategy. We present a wide range of code tests including the Sod shock tube,
Sedov-Taylor blast wave, Kelvin-Helmholtz Instability, the `blob test', and
some convergence tests. Our method performs well on all tests, giving good
agreement with analytic expectations.Comment: 21 pages; 15 Figures. Submitted to MNRAS. Comments welcom
Josephson array of mesoscopic objects. Modulation of system properties through the chemical potential
The phase diagram of a two-dimensional Josephson array of mesoscopic objects
is examined. Quantum fluctuations in both the modulus and phase of the
superconducting order parameter are taken into account within a lattice boson
Hubbard model. Modulating the average occupation number of the sites in
the system leads to changes in the state of the array, and the character of
these changes depends significantly on the region of the phase diagram being
examined. In the region where there are large quantum fluctuations in the phase
of the superconducting order parameter, variation of the chemical potential
causes oscillations with alternating superconducting (superfluid) and normal
states of the array. On the other hand, in the region where the bosons interact
weakly, the properties of the system depend monotonically on . Lowering
the temperature and increasing the particle interaction force lead to a
reduction in the width of the region of variation in within which the
system properties depend weakly on the average occupation number. The phase
diagram of the array is obtained by mapping this quantum system onto a
classical two-dimensional XY model with a renormalized Josephson coupling
constant and is consistent with our quantum Path-Integral Monte Carlo
calculations.Comment: 12 pages, 8 Postscript figure
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