165 research outputs found
Defective Behaviour of an 8T SRAM Cell with Open Defects
The defective behaviour of an 8T SRAM cell with open defects is analyzed. Full and resistive open defects have been considered in the electrical characterization of the defective cell. Due to the similarity between the classical 6T SRAM cell and the 8T cell, only defects affecting the read port transistors have been considered. In the work, it is shown how an open in a defective cell may influence the correct operation of a victim cell sharing the same read circuitry. Also, it is shown that the sequence of bits written on the defective cell prior to a read action can mask the presence of the defect. Different orders of critical resistance have been found depending on the location of the open defect. A 45nm technology has been used for the illustrative example presented in the wor
Subaru and Swift observations of V652 Herculis: resolving the photospheric pulsation
High-resolution spectroscopy with the Subaru High Dispersion Spectrograph, and Swift ultraviolet photometry are presented for the pulsating extreme helium star V652 Her. Swift provides the best relative ultraviolet photometry obtained to date, but shows no direct evidence for a shock at ultraviolet or X-ray wavelengths. Subaru has provided high spectral and high temporal resolution spectroscopy over six pulsation cycles (and eight radius minima).
These data have enabled a line-by-line analysis of the entire pulsation cycle and provided a description of the pulsating photosphere as a function of optical depth. They show that the photosphere is compressed radially by a factor of at least 2 at minimum radius, that the phase of radius minimum is a function of optical depth and the pulse speed through the photosphere is between 141 and 239 km s−1 (depending how measured) and at least 10 times the local sound speed. The strong acceleration at minimum radius is demonstrated in individual line profiles; those formed deepest in the photosphere show a jump discontinuity of over 70 kms−1 on a time-scale of 150 s. The pulse speed and line profile jumps imply a shock is present at minimum radius. These empirical results provide input for hydrodynamical modelling of the pulsation and hydrodynamical plus radiative transfer modelling of the dynamical spectra
Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system
We announce confirmation of Kepler-418b, one of two proposed planets in this
system. This is the first confirmation of an exoplanet based primarily on the
transit color signature technique. We used the Kepler public data archive
combined with multicolor photometry from the Gran Telescopio de Canarias and
radial velocity follow-up using FIES at the Nordic Optical Telescope for
confirmation. We report a confident detection of a transit color signature that
can only be explained by a compact occulting body, entirely ruling out a
contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing
binary. Those findings are corroborated by our radial velocity measurements,
which put an upper limit of ~1 Mjup on the mass of Kepler-418b. We also report
that the host star is significantly blended, confirming the ~10% light
contamination suspected from the crowding metric in the Kepler light curve
measured by the Kepler team. We report detection of an unresolved light source
that contributes an additional ~40% to the target star, which would not have
been detected without multicolor photometric analysis. The resulting
planet-star radius ratio is 0.110 +/- 0.0025, more than 25% more than the 0.087
measured by Kepler, leading to a radius of 1.20 +/- 0.16 Rjup instead of the
0.94 Rjup measured by the Kepler team. This is the first confirmation of an
exoplanet candidate based primarily on the transit color signature,
demonstrating that this technique is viable from ground for giant planets. It
is particularly useful for planets with long periods such as Kepler-418b, which
tend to have long transit durations. Additionally, multicolor photometric
analysis of transits can reveal unknown stellar neighbors and binary companions
that do not affect the classification of the transiting object but can have a
very significant effect on the perceived planetary radius.Comment: accepted by Astronomy & Astrophysic
Aplicación de un modelo híbrido de aprendizaje profundo para el análisis de sentimiento en twitter
En este artículo se describe la participación de ITAINNOVA en la tarea de análisis de sentimiento a nivel de Tweet dentro del taller TASS 2018. Este trabajo pretende explorar modelos presentes en el estado del arte actual del aprendizaje profundo aplicado al modelado y clasificación de texto. Se ha analizado el uso de modelos de redes convolucionales (CNN), Long short Term Memory (LSTM), LSTM bidireccionales (BI-LSTM) y una aproximación híbrida entre CNN y LSTM para su uso en el análisis de sentimiento en Twitter. Se ha optado por la combinación CNN- LSTM ya que integra los beneficios de ambos modelos. Finalmente se presentan los resultados obtenidos y se plantea una posible línea de trabajo futura que combine el uso de esta arquitectura con el algoritmo de representación de texto que presentamos en la anterior edición del TASS.
This paper describes the participation of ITAINNOVA at sentiment analysis at Tweet level task within TASS 2018 workshop. This work explores current state of the art models used in deep learning for modelling and classification tasks over text. It analyzes convolutional neural models (CNN), Long short Term Memory (LSTM), Bidirectional LSTM (BI-LSTM) and an hybrid approach of CNN-LSTM, for its use in sentiment analysis on Twitter data. CNN-LSTM combination has been chosen as it integrates the benefits provided from both models. Finally, obtained results are presented and a possible future work line which combines this architecture with the algorithm presented in the previous TASS edition
Release of Ropinirole from Acrylate-Vinylacetate Transdermal Formulations: Modulation Based on Polymer-Drug Interactions
Optimization of transdermal formulations requires solving simultaneous challenges as the selection of release polymers. The interactions between the formulation components must be taken as a way to modulate its performance. Selection of acrylic polymers with different functionalizations for the transdermal formulation of a tertiary amine drug (ropinirole HCl) have been investigated. Aim of this work is to characterize the influence over drug release of certain experimental interactions. Solubility-crystalization and pharmacopoeial release tests have been used to evaluate the influence of drug loading and the pH of the release media. Area under the curve of dissolved amounts and percentage of release have been used as discriminant variables in mutual influence with the physical state of the drug. Elucidation of release mechanisms has been performed with data fitting of relevant modelystic equations. Fickian release and erosion contribution have been related with drug loading and the risk of burst effects. In conclusion, a rationale to select the best suitable polymer for ropinirole HCl has been demonstrated in terms of efficiency and extent of release
8T SRAM Defective Cell with Open Defects
The defective behaviour of an 8T SRAM cell with open defects is analyzed. Full and resistive open defects have been considered in the electrical characterization of the defective cell. Due to the similarity between the classical 6T SRAM cell and the 8T cell, only defects affecting the read port transistors have been considered. In the work, it is shown how an open in a defective cell may influence the correct operation of a victim cell sharing the same read circuitry. Also, it is shown that the sequence of bits written on the defective cell prior to a read action can mask the presence of the defect. Different orders of critical resistance have been found depending on the location of the open defect. A 45nm technology has been used for the illustrative example presented in the wor
The EBLM project. II. A very hot, low-mass M dwarf in an eccentric and long period eclipsing binary system from SuperWASP
In this paper, we derive the fundamental properties of
1SWASPJ011351.29+314909.7 (J0113+31), a metal-poor (-0.40 +/- 0.04 dex),
eclipsing binary in an eccentric orbit (~0.3) with an orbital period of ~14.277
d. Eclipsing M dwarfs orbiting solar-type stars (EBLMs), like J0113+31, have
been identified from WASP light curves and follow-up spectroscopy in the course
of the transiting planet search. We present the first binary of the EBLM sample
to be fully analysed, and thus, define here the methodology. The primary
component with a mass of 0.945 +/- 0.045 Msun has a large radius (1.378 +/-
0.058 Rsun) indicating that the system is quite old, ~9.5 Gyr. The M-dwarf
secondary mass of 0.186 +/- 0.010 Msun and radius of 0.209 +/- 0.011 Rsun are
fully consistent with stellar evolutionary models. However, from the
near-infrared secondary eclipse light curve, the M dwarf is found to have an
effective temperature of 3922 +/- 42 K, which is ~600 K hotter than predicted
by theoretical models. We discuss different scenarios to explain this
temperature discrepancy. The case of J0113+31 for which we can measure mass,
radius, temperature and metallicity, highlights the importance of deriving
mass, radius and temperature as a function of metallicity for M dwarfs to
better understand the lowest mass stars. The EBLM Project will define the
relationship between mass, radius, temperature and metallicity for M dwarfs
providing important empirical constraints at the bottom of the main sequence.Comment: 13 pages, 7 figures. Accepted for publication in A&
Automated Observations of the Earthshine
The overall reflectance of sunlight from Earth is a fundamental parameter
for climate studies. We have designed and implemented small aperture, remote
control telescopes in Big Bear Solar Observatory in California and in Tenerife in
the Canary Islands. These telescopes observe the earthshine to obtain a global
mean terrestrial reflectance utilizing a coronagraph-like design for long exposures
of the dark of the Moon and have internal moving parts in the optical train, which
presented some design and control problems
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