1,528 research outputs found
Statistical properties of thermodynamically predicted RNA secondary structures in viral genomes
By performing a comprehensive study on 1832 segments of 1212 complete genomes
of viruses, we show that in viral genomes the hairpin structures of
thermodynamically predicted RNA secondary structures are more abundant than
expected under a simple random null hypothesis. The detected hairpin structures
of RNA secondary structures are present both in coding and in noncoding regions
for the four groups of viruses categorized as dsDNA, dsRNA, ssDNA and ssRNA.
For all groups hairpin structures of RNA secondary structures are detected more
frequently than expected for a random null hypothesis in noncoding rather than
in coding regions. However, potential RNA secondary structures are also present
in coding regions of dsDNA group. In fact we detect evolutionary conserved RNA
secondary structures in conserved coding and noncoding regions of a large set
of complete genomes of dsDNA herpesviruses.Comment: 9 pages, 2 figure
Test of the ATLAS pion calibration scheme in the ATLAS combined test beam
Pion energy reconstruction is studied using the data collected during the
2004 ATLAS combined test beam. The strategy to extract corrections for the
non-compensating nature of the ATLAS calorimeters for dead material losses and
for leakage effects is discussed and assessed. The default ATLAS strategy based
on a weighting technique of the energy deposits in calorimeter cells is
presented and compared to a novel technique exploiting correlations among
energy deposited in calorimeter layers.Comment: 8 pages, 6 figures, to appear in the Proceedings of the XIII
International Conference on Calorimetry in High Energy Physics (CALOR08), May
2008, Pavia, Italy - Journal of Physics: Conference Serie
A Layer Correlation Technique for ATLAS Calorimetry Calibration at the 2004 ATLAS Combined Beam Test
A method for calibrating the response of a segmented calorimeter to hadrons is developed. The ansatz is that information on longitudinal shower fluctuations gained from a principal component analysis of the layer energy depositions can improve energy resolution by correcting for hadronic invisible energy and dead material losses: projections along the eigenvectors of the correlation matrix are used as input for the calibration. The technique is used to reconstruct the energy of pions impinging on the ATLAS calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. Simulated Monte Carlo events are used to derive corrections for invisible energy lost in nuclear reactions and in dead material in front and in between the calorimeters. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the resolution is improved by about 20%
TLS MODELS GENERATION ASSISTED BY UAV SURVEY
By now the documentation and 3D modelling activities of built heritage concern in an almost usual way terrestrial Lidar techniques (TLS, Terrestrial Laser Scanning), and large scale mapping derived by UAV (Unmanned Aerial Vehicle) survey. This paper refers an example of 3D survey and reality based modelling applied on landscape and architectural assets. The choice of methods for documentation, in terms of survey techniques, depends primarily on issues and features of the area.
The achieved experience, allow to consider that the easy handling of TLS has enabled the use in limited spaces among buildings and collapsed roofs, but the topographic measure of GCPs (Ground Control Points), neither by total station nor by GPS/RTK technique, was easily feasible. Even more than proving the ability of the integration of TLS and UAV photogrammetry to achieve a multi-source and multi-scale whole model of a village, the experience has been a test to experiment the registration of terrestrial clouds with the support of control points derived by UAV survey and finally, a comparison among different strategies of clouds registration is reported. Analysing for each approach a number of parameters (number of clouds registration, number of needed points, processing time, overall accuracy) the further comparisons have been achieved.
The test revealed that it is possible to decrease the large number of terrestrial control points when their determination by topographical measures is difficult, and it is possible to combine the techniques not only for the integration of the final 3Dmodel, but also to solve and make the initial stage of the drafting process more effective
Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)
This aim of paper is to presents the development of a multidisciplinary project carried
out by the cooperation between Politecnico di Torino and ITHACA (Information
Technology for Humanitarian Assistance, Cooperation and Action). The
goal of the project was the training in geospatial data acquiring and processing for
students attending Architecture and Engineering Courses, in order to start up a
team of “volunteer mappers”. Indeed, the project is aimed to document the environmental
and built heritage subject to disaster; the purpose is to improve the capabilities
of the actors involved in the activities connected in geospatial data collection,
integration and sharing. The proposed area for testing the training
activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According
to other international experiences, the group is expected to be active after
emergencies in order to upgrade maps, using data acquired by typical geomatic
methods and techniques such as terrestrial and aerial Lidar, close-range and aerial
photogrammetry, topographic and GNSS instruments etc.; or by non conventional
systems and instruments such us UAV, mobile mapping etc. The ultimate goal is
to implement a WebGIS platform to share all the data collected with local authorities
and the Civil Protection
The optical head of the EnVisS camera for the Comet Interceptor ESA mission: Phase 0 study
EnVisS (Entire Visible Sky) is an all-sky camera specifically designed to fly on the space mission Comet Interceptor. This mission has been selected in June 2019 as the first European Space Agency (ESA) Fast mission, a modest size mission with fast implementation. Comet Interceptor aims to study a dynamically new comet, or interstellar object, and its launch is scheduled in 2029 as a companion to the ARIEL mission. The mission study phase, called Phase 0, has been completed in December 2019, and then the Phase A study had started. Phase A will last for about two years until mission adoption expected in June 2022. The Comet Interceptor mission is conceived to be composed of three spacecraft: spacecraft A devoted to remote sensing science, and the other two, spacecraft B1 and B2, dedicated to a fly-by with the comet. EnVisS will be mounted on spacecraft B2, which is foreseen to be spin-stabilized. The camera is developed with the scientific task to image, in push-frame mode, the full comet coma in different colors. A set of ad-hoc selected broadband filters and polarizers in the visible range will be used to study the full scale distribution of the coma gas and dust species. The camera configuration is a fish-eye lens system with a FoV of about 180°x45°. This paper will describe the preliminary EnVisS optical head design and analysis carried out during the Phase 0 study of the mission
DIGITAL REPLICAS OF BRITISH MUSEUM ARTEFACTS
The digitisation of museum exhibits has played an essential role in geomatics research for generating digital replicas, as it offers the chance to address rather challenging issues. The use of different sensors, ranging from active to passive, and also structured light scanners or hybrid solutions, the various destinations and purposes of the final results combined with the extreme variety of possible objects have made it a field of investigation highly inquired in the literature.The present study aims to analyse and discuss a digitalisation workflow applied to four Sumerian civilisation masterpieces preserved in the British Museum. The dense and accurate 3D point clouds derived from a specimen of Articulated Arm Coordinate Measuring Machines in collaboration with Faro technologies have twofold roles: ground truth and geometric reference of the final digital replicas. Digital photogrammetry is employed to enrich the models with the relevant radiometric component. The significant contribution results, exploiting co-registration strategies, offer careful guidance of a photogrammetric protocol created in a highly controlled environment combined with skilful expedients and devices. The proposed approach enables the acquisition of high-quality and radiometrically balanced images and improves the possibility of automating the masking procedure before the photogrammetric processing.</p
Mezzi aerei non convenzionali a volo autonomo per il rilievo fotogrammetrico in ambito archeologico
I rilievi fotogrammetrici aerei sono generalmente costosi e permettono comunque di acquisire immagini con risoluzione limitata a causa delle quote a cui possono generalmente volare gli aerei attrezzati. Per questa ragione, sono stati sviluppati e verificati numerosi sistemi in grado di acquisire immagini digitali ad alta risoluzione per applicazioni fotogrammetriche a basso costo (palloni aerostatici, mongolfiere, aerei ed elicotteri ultraleggeri, ecc.): in questo ambito, i mezzi aerei non convenzionali a volo autonomo (in inglese Unmanned Aerial Vehicle, UAV) rappresentano una delle tecniche piĂą promettenti se dotati di camera digitale ad alta risoluzione.
In questo contributo, gli autori descrivono le modalità operative per l’acquisizione di immagini digitali a bassa quota mediante UAV multi-rotore e la loro successiva elaborazione per produrre, nel modo più automatico possibile, un supporto cartografico a grandissima scala (l’ortofoto solida di precisione) di ausilio a studi archeologici
GYES, a multifibre spectrograph for the CFHT
We have chosen the name of GYES, one of the mythological giants with one
hundred arms, offspring of Gaia and Uranus, for our instrument study of a
multifibre spectrograph for the prime focus of the Canada-France-Hawaii
Telescope. Such an instrument could provide an excellent ground-based
complement for the Gaia mission and a northern complement to the HERMES project
on the AAT. The CFHT is well known for providing a stable prime focus
environment, with a large field of view, which has hosted several imaging
instruments, but has never hosted a multifibre spectrograph. Building upon the
experience gained at GEPI with FLAMES-Giraffe and X-Shooter, we are
investigating the feasibility of a high multiplex spectrograph (about 500
fibres) over a field of view 1 degree in diameter. We are investigating an
instrument with resolution in the range 15000 to 30000, which should provide
accurate chemical abundances for stars down to 16th magnitude and radial
velocities, accurate to 1 km/s for fainter stars. The study is led by
GEPI-Observatoire de Paris with a contribution from Oxford for the study of the
positioner. The financing for the study comes from INSU CSAA and Observatoire
de Paris. The conceptual study will be delivered to CFHT for review by October
1st 2010.Comment: Contributed talk at the Gaia ELSA conference 2010, S\`evres 7-11 June
2010, to be published on the EAS Series, Editors: C. Turon, F. Arenou & F.
Meynadie
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