57,391 research outputs found
SIRIO : Integrated Forest Firesmonitoring, detection and decision supportsystem with low cost commercial sensorssuited for complex orography
Forest Fires in our society cause a lot of damage, in particular regarding the economic and environmental landscape. In order to monitor a large portion of territory automatically, with a good cost/performances trade-off, it is necessary to develop new early warning systems. We propose a ground-based system with modular architecture, equipped with low cost commercial sensor. The idea is to develop the software able to manage the forest fires monitoring. The technique is based on Static and Dynamic analysis of chromatic changes between images, tailored for our case of study in a large scale monitoring of vegetation and using different sensors to reduce or eliminate the false alarm rate. Concerning the image geo-referencing tool, the present work describes an innovative projective geo-referencing algorithm able to geo-reference complex orography regions using fixed ground station images. Besides, it does not need the collection of Ground Control Points, which is a very hard task in complex orography environments. In order to make a user oriented product and to help the operator during extinguishing activities, a decision support tool has been developed as well. This work presents the results of one year monitoring campaign conducted in cooperation with the Civil Protection Offices in Sanremo (IM), Ital
Exoplanet Transmission Spectroscopy using KMOS
KMOS (K-Band Multi Object Spectrograph) is a novel integral field
spectrograph installed in the VLT's ANTU unit. The instrument offers an ability
to observe 24 2.8"2.8" sub-fields positionable within a 7.2' patrol
field, each sub-field producing a spectrum with a 1414-pixel spatial
resolution. The main science drivers for KMOS are the study of galaxies, star
formation, and molecular clouds, but its ability to simultaneously measure
spectra of multiple stars makes KMOS an interesting instrument for exoplanet
atmosphere characterization via transmission spectroscopy. We set to test
whether transmission spectroscopy is practical with KMOS, and what are the
conditions required to achieve the photometric precision needed, based on
observations of a partial transit of WASP-19b, and full transits of GJ 1214b
and HD 209458b. Our analysis uses the simultaneously observed comparison stars
to reduce the effects from instrumental and atmospheric sources, and Gaussian
processes to model the residual systematics. We show that KMOS can, in theory,
deliver the photometric precision required for transmission spectroscopy.
However, this is shown to require a) pre-imaging to ensure accurate centering
and b) a very stable night with optimal observing conditions (seeing
0.8"). Combining these two factors with the need to observe several
transits, each with a sufficient out-of-transit baseline (and with the fact
that similar or better precision can be reached with telescopes and instruments
with smaller pressure,) we conclude that transmission spectroscopy is not the
optimal science case to take advantage of the abilities offered by KMOS and
VLT.Comment: 11 pages, accepted to MNRA
HATS-5b: A Transiting hot-Saturn from the HATSouth Survey
We report the discovery of HATS-5b, a transiting hot-Saturn orbiting a G type
star, by the HAT-South survey. HATS-5b has a mass of Mp=0.24 Mj, radius of
Rp=0.91 Rj, and transits its host star with a period of P=4.7634d. The radius
of HATS-5b is consistent with both theoretical and empirical models. The host
star has a V band magnitude of 12.6, mass of 0.94 Msun, and radius of 0.87
Rsun. The relatively high scale height of HATS-5b, and the bright,
photometrically quiet host star, make this planet a favourable target for
future transmission spectroscopy follow-up observations. We reexamine the
correlations in radius, equilibrium temperature, and metallicity of the
close-in gas-giants, and find hot Jupiter-mass planets to exhibit the strongest
dependence between radius and equilibrium temperature. We find no significant
dependence in radius and metallicity for the close-in gas-giant population.Comment: 10 pages, submitted to A
Extracting More Data from LiDAR in Forested Areas by Analyzing Waveform Shape
Light Detection And Ranging (LiDAR) in forested areas is used for constructing Digital Terrain Models (DTMs), estimating biomass carbon and timber volume and estimating foliage distribution as an indicator of tree growth and health. All of these purposes are hindered by the inability to distinguish the source of returns as foliage, stems, understorey and the ground except by their relative positions. The ability to separate these returns would improve all analyses significantly. Furthermore, waveform metrics providing information on foliage density could improve forest health and growth estimates. In this study, the potential to use waveform LiDAR was investigated. Aerial waveform LiDAR data were acquired for a New Zealand radiata pine plantation forest, and Leaf Area Density (LAD) was measured in the field. Waveform peaks with a good signal-to-noise ratio were analyzed and each described with a Gaussian peak height, half-height width, and an exponential decay constant. All parameters varied substantially across all surface types, ruling out the potential to determine source characteristics for individual returns, particularly those with a lower signal-to-noise ratio. However, pulses on the ground on average had a greater intensity, decay constant and a narrower peak than returns from coniferous foliage. When spatially averaged, canopy foliage density (measured as LAD) varied significantly, and was found to be most highly correlated with the volume-average exponential decay rate. A simple model based on the Beer-Lambert law is proposed to explain this relationship, and proposes waveform decay rates as a new metric that is less affected by shadowing than intensity-based metrics. This correlation began to fail when peaks with poorer curve fits were included
Multi-stage Suture Detection for Robot Assisted Anastomosis based on Deep Learning
In robotic surgery, task automation and learning from demonstration combined
with human supervision is an emerging trend for many new surgical robot
platforms. One such task is automated anastomosis, which requires bimanual
needle handling and suture detection. Due to the complexity of the surgical
environment and varying patient anatomies, reliable suture detection is
difficult, which is further complicated by occlusion and thread topologies. In
this paper, we propose a multi-stage framework for suture thread detection
based on deep learning. Fully convolutional neural networks are used to obtain
the initial detection and the overlapping status of suture thread, which are
later fused with the original image to learn a gradient road map of the thread.
Based on the gradient road map, multiple segments of the thread are extracted
and linked to form the whole thread using a curvilinear structure detector.
Experiments on two different types of sutures demonstrate the accuracy of the
proposed framework.Comment: Submitted to ICRA 201
Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
We report the initial results of our high-cadence monitoring program on the
radio jet in the active galaxy M87, obtained by the KVN and VERA Array (KaVA)
at 22 GHz. This is a pilot study that preceded a larger KaVA-M87 monitoring
program, which is currently ongoing. The pilot monitoring was mostly performed
every two to three weeks from December 2013 to June 2014, at a recording rate
of 1 Gbps, obtaining the data for a total of 10 epochs. We successfully
obtained a sequence of good quality radio maps that revealed the rich structure
of this jet from <~1 mas to 20 mas, corresponding to physical scales
(projected) of ~0.1-2 pc (or ~140-2800 Schwarzschild radii). We detected
superluminal motions at these scales, together with a trend of gradual
acceleration. The first evidence for such fast motions and acceleration near
the jet base were obtained from recent VLBA studies at 43 GHz, and the fact
that very similar kinematics are seen at a different frequency and time with a
different instrument suggests these properties are fundamental characteristics
of this jet. This pilot program demonstrates that KaVA is a powerful VLBI array
for studying the detailed structural evolution of the M87 jet and also other
relativistic jets.Comment: 10 pages, 9 figures, accepted for publication in PAS
A two-dimensional data-driven model for traffic flow on highways
Based on experimental traffic data obtained from German and US highways, we
propose a novel two-dimensional first-order macroscopic traffic flow model. The
goal is to reproduce a detailed description of traffic dynamics for the real
road geometry. In our approach both the dynamic along the road and across the
lanes is continuous. The closure relations, being necessary to complete the
hydrodynamic equation, are obtained by regression on fundamental diagram data.
Comparison with prediction of one-dimensional models shows the improvement in
performance of the novel model.Comment: 27 page
Redshift Determination and CO Line Excitation Modeling for the Multiply Lensed Galaxy HLSW-01
We report on the redshift measurement and CO line excitation of HERMES J105751.1+573027 (HLSW-01), a strongly lensed submillimeter galaxy discovered in Herschel/SPIRE observations as part of the Herschel Multi-tiered Extragalactic Survey (HerMES). HLSW-01 is an ultra-luminous galaxy with an intrinsic far-infrared luminosity of L _(FIR) = 1.4 Ă 10^(13) L _â, and is lensed by a massive group of galaxies into at least four images with a total magnification of ÎŒ = 10.9 ± 0.7. With the 100 GHz instantaneous bandwidth of the Z-Spec instrument on the Caltech Submillimeter Observatory, we robustly identify a redshift of z = 2.958 ± 0.007 for this source, using the simultaneous detection of four CO emission lines (J = 7 â 6, J = 8 â 7, J = 9 â 8, and J = 10 â 9). Combining the measured line fluxes for these high-J transitions with the J = 1 â 0, J = 3 â 2, and J = 5 â 4 line fluxes measured with the Green Bank Telescope, the Combined Array for Research in Millimeter Astronomy, and the Plateau de Bure Interferometer, respectively, we model the physical properties of the molecular gas in this galaxy. We find that the full CO spectral line energy distribution is described well by warm, moderate-density gas with T _(kin) = 86-235 K and n_H_2 = (1.1-3.5)x10^3 cm^(â3). However, it is possible that the highest-J transitions are tracing a small fraction of very dense gas in molecular cloud cores, and two-component models that include a warm/dense molecular gas phase with T _(kin) ~ 200 K, n_H_2 ~ 10^5 cm^(â3) are also consistent with these data. Higher signal-to-noise measurements of the J _(up) â„ 7 transitions with high spectral resolution, combined with high spatial resolution CO maps, are needed to improve our understanding of the gas excitation, morphology, and dynamics of this interesting high-redshift galaxy
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