9,487 research outputs found
Music Boundary Detection using Convolutional Neural Networks: A comparative analysis of combined input features
The analysis of the structure of musical pieces is a task that remains a
challenge for Artificial Intelligence, especially in the field of Deep
Learning. It requires prior identification of structural boundaries of the
music pieces. This structural boundary analysis has recently been studied with
unsupervised methods and \textit{end-to-end} techniques such as Convolutional
Neural Networks (CNN) using Mel-Scaled Log-magnitude Spectograms features
(MLS), Self-Similarity Matrices (SSM) or Self-Similarity Lag Matrices (SSLM) as
inputs and trained with human annotations. Several studies have been published
divided into unsupervised and \textit{end-to-end} methods in which
pre-processing is done in different ways, using different distance metrics and
audio characteristics, so a generalized pre-processing method to compute model
inputs is missing. The objective of this work is to establish a general method
of pre-processing these inputs by comparing the inputs calculated from
different pooling strategies, distance metrics and audio characteristics, also
taking into account the computing time to obtain them. We also establish the
most effective combination of inputs to be delivered to the CNN in order to
establish the most efficient way to extract the limits of the structure of the
music pieces. With an adequate combination of input matrices and pooling
strategies we obtain a measurement accuracy of 0.411 that outperforms the
current one obtained under the same conditions
Analysis of the saltwater wedge in a coastal karst aquifer with a double conduit network, numerical simulations and sensitivity analysis
We investigate the long-distance salinity in a dual permeability coastal karst aquifer with a double conduit network using a three-dimensional variable-density groundwater flow and multispecies transport SEAWAT model. Sensitivity analyses were used to evaluate the impact of the parameters and boundary conditions on the modeling saltwater wedge in a karstic aquifer situated in the Cuban land territory, including hydraulic conductivity, vertical anisotropy and salinity concentration; both in the conduits network and the fractured medium. These analyses indicated that hydraulic conductivity of the fractured medium and salt concentration were the ones that have a stronger effect on saltwater intrusion in a karstic aquifer. We also show results of the three-dimensional numerical simulations on groundwater salinity for different scenarios with the variabilities of the important parameters and compare results with electric conductivity profiles measured in a well
Ultimate response dynamics achieved with gas sensors based on self-heated nanowires
Bias current applied to conductometric gas sensors consisting of individual metal oxide nanowires can be used to heat them up to the temperature necessary for sensing. This approach in combination with the good sensitivity and stability of metal-oxide nanowires, can be used to develop prototypes with low power requirements (few tens of microwatts). Here, we present new sensors devices based on this approach that display fast dynamic performance only limited by the gas-solid interaction kinetics,. © 2009
Extraction of Generalized Parton Distribution Observables from Deeply Virtual Electron Proton Scattering Experiments
We provide the general expression of the cross section for exclusive deeply
virtual photon electroproduction from a spin 1/2 target using current
parameterizations of the off-forward correlation function in a nucleon for
different beam and target polarization configurations up to twist three
accuracy. All contributions to the cross section including deeply virtual
Compton scattering, the Bethe-Heitler process, and their interference, are
described within a helicity amplitude based framework which is also
relativistically covariant and readily applicable to both the laboratory frame
and in a collider kinematic setting. Our formalism renders a clear physical
interpretation of the various components of the cross section by making a
connection with the known characteristic structure of the electron scattering
coincidence reactions. In particular, we focus on the total angular momentum,
, and on the orbital angular momentum, . On one side, we uncover an
avenue to a precise extraction of , given by the combination of
generalized parton distributions, , through a generalization of the
Rosenbluth separation method used in elastic electron proton scattering. On the
other, we single out for the first time, the twist three angular modulations of
the cross section that are sensitive to . The proposed generalized
Rosenbluth technique adds an important constraint for mapping the 3D structure
of the nucleon.Comment: 62 pages, 7 figures, 3 table
Anthropic Action on Historical Shoreline Changes and Future Estimates Using GIS: Guadarmar Del Segura (Spain)
A good understanding of historical change rates is a key requirement for effective coastal zone management and reliable predictions of shoreline evolution. Historical shoreline erosion for the coast of Guardamar del Segura (Alicante, Spain) is analyzed based on aerial photographs dating from 1930 to 2022 using the Digital Shoreline Analysis System (DSAS). This area is of special interest because the construction of a breakwater in the 1990s, which channels the mouth of the Segura River, has caused a change in coastal behavior. The prediction of future shorelines is conducted up to the year 2040 using two models based on data analysis techniques: the extrapolation of historical data (including the uncertainty of the historical measurements) and the Bruun-type model (considering the effect of sea level rises). The extrapolation of the natural erosion of the area up to 1989 is also compared with the reality, already affected by anthropic actions, in the years 2005 and 2022. The construction of the breakwater has accelerated the erosion along the coast downstream of this infrastructure by about 260%, endangering several houses that are located on the beach itself. The estimation models predict transects with erosions ranging from centimeters (±70 cm) to tens of meters (±30 m). However, both models are often overlapping, which gives a band where the shoreline may be thought to be in the future. The extrapolation of erosion up to 1989, and its subsequent comparison, shows that in most of the study areas, anthropic actions have increased erosion, reaching values of more than 35 m of shoreline loss. The effect of anthropic actions on the coast is also analyzed on the housing on the beach of Babilonia, which has lost around 17% of its built-up area in 40 years. This work demonstrates the importance of historical analysis and predictions before making any significant changes in coastal areas to develop sustainable plans for coastal area management
SSDSS IV MaNGA - Properties of AGN host galaxies
We present here the characterization of the main properties of a sample of 98
AGN host galaxies, both type-II and type-I, in comparison with those of about
2700 non-active galaxies observed by the MaNGA survey. We found that AGN hosts
are morphologically early-type or early-spirals. For a given morphology AGN
hosts are, in average, more massive, more compact, more central peaked and
rather pressurethan rotational-supported systems. We confirm previous results
indicating that AGN hosts are located in the intermediate/transition region
between star-forming and non-star-forming galaxies (i.e., the so-called green
valley), both in the ColorMagnitude and the star formation main sequence
diagrams. Taking into account their relative distribution in terms of the
stellar metallicity and oxygen gas abundance and a rough estimation of their
molecular gas content, we consider that these galaxies are in the process of
halting/quenching the star formation, in an actual transition between both
groups. The analysis of the radial distributions of the starformation rate,
specific star-formation rate, and molecular gas density shows that the
quenching happens from inside-out involving both a decrease of the efficiency
of the star formation and a deficit of molecular gas. All the intermediate
data-products used to derive the results of our analysis are distributed in a
database including the spatial distribution and average properties of the
stellar populations and ionized gas, published as a Sloan Digital Sky Survey
Value Added Catalog being part of the 14th Data Release:
http://www.sdss.org/dr14/manga/manga-data/manga-pipe3d-value-added-catalog/Comment: 48 pages, 14 figures, in press in RMxA
Infrared spectral fingerprint of neutral and charged endo- and exohedral metallofullerenes
Small metal-containing molecules have been detected and recognized as one of
the hybrid species efficiently formed in space; especially in the circumstellar
envelopes of evolved stars. It has been predicted also that more complex hybrid
species like those formed by metals and fullerenes (metallofullerenes) could be
present in such circumstellar environments. Recently, quantum-chemical
simulations of metallofullerenes have shown that they are potential emitters
contributing to the observed mid-IR spectra in the fullerene-rich circumstellar
environments of different types of evolved stars. Here we present the
individual simulated mid-IR (~5-50 um) spectra of twenty-eight metallofullerene
species; both neutral and charged endo- and exohedral metallofullerenes for
seven different metals (Li, Na, K, Ca, Mg, Ti, and Fe) have been considered.
The changes induced by the metal-C60 interaction on the intensity and position
of the spectral features are highlighted using charge density difference maps
and electron density partitioning. Our calculations identify the fundamental IR
spectral regions where, depending on the metal binding nature, there should be
a major spectral contribution from each of the metallofullerenes. The
metallofullerenes IR spectra are made publicly available to the astronomical
community, especially James Webb Space Telescope users, for comparisons that
could eventually lead to the detection of these species in space.Comment: Accepted for publication in The Astrophysical Journal Supplement
Series on 19 September 2023 (in press) (13 pages, 7 figures, and 1 table
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