The search for extrasolar giant planets using integral field spectroscopy: Simulations     

Alessandro Berton  Markus Feldt  Raffaele Gratton  Stefan Hippler  Thomas Henning 《New Astronomy Reviews》2006,49(10-12):661

We present here simulations of extrasolar planets detections obtained using a combination of extreme adaptive optics and integral field spectroscopy. The simulation code, written for IDL, provides images and, in particular, spectra, taking into account realistic Speckle Noise, AO correction effects and specific instrumental features. A detailed study has been done for ESO VLT telescopes (8.2 m), within the Phase A of the CHEOPS project, but the code is particularly flexible and can be updated for larger telescope diameters (ELTs) in order to give a realistic estimate of the detection limits, for giant telescopes, in standard conditions of seeing.  相似文献   

Serviceability analysis of piled foundations supporting tall structures     

Iovino  Maria  Di Laora  Raffaele  de Sanctis  Luca 《Acta Geotechnica》2021,16(12):3963-3973

Acta Geotechnica - Pile foundations supporting tall structures, such as wind turbines, chimneys, silos, elevated water tanks or bridge piers, are subjected during their life span to remarkably...  相似文献   

A Bayesian vulnerability assessment tool for drinking water mains under extreme events   总被引：2，自引：1，他引：1  

Alessandro Pagano  Raffaele Giordano  Ivan Portoghese  Umberto Fratino  Michele Vurro 《Natural Hazards》2014,74(3):2193-2227

Drinking water security is a life safety issue as an adequate supply of safe water is essential for economic, social and sanitary reasons. Damage to any element of a water system, as well as corruption of resource quality, may have significant effects on the population it serves and on all other dependent resources and activities. As well as an analysis of the reliability of water distribution systems in ordinary conditions, it is also crucial to assess system vulnerability in the event of natural disasters and of malicious or accidental anthropogenic acts. The present work summarizes the initial results of research activities that are underway with the intention of developing a vulnerability assessment methodology for drinking water infrastructures subject to hazardous events. The main aim of the work was therefore to provide decision makers with an effective operational tool which could support them mainly to increase risk awareness and preparedness and, possibly, to ease emergency management. The proposed tool is based on Bayesian Belief Networks (BBN), a probabilistic methodology which has demonstrated outstanding potential to integrate a range of sources of knowledge, a great flexibility and the ability to handle in a mathematically sound way uncertainty due to data scarcity and/or limited knowledge of the system to be managed. The tool was implemented to analyze the vulnerability of two of the most important water supply systems in the Apulia region (southern Italy) which have been damaged in the past by natural hazards. As well as being useful for testing and improving the predictive capabilities of the methodology and for possibly modifying its structure and features, the case studies have also helped to underline its strengths and weaknesses. Particularly, the experiences carried out demonstrated how the use of BBN was consistent with the lack of data reliability, quality and accessibility which are typical of complex infrastructures, such as the water distribution networks. The potential applications and future developments of the proposed tool have been also discussed accordingly.  相似文献   

SPICES: spectro-polarimetric imaging and characterization of exoplanetary systems     

Anthony Boccaletti  Jean Schneider  Wes Traub  Pierre-Olivier Lagage  Daphne Stam  Raffaele Gratton  John Trauger  Kerri Cahoy  Frans Snik  Pierre Baudoz  Raphael Galicher  Jean-Michel Reess  Dimitri Mawet  Jean-Charles Augereau  Jenny Patience  Marc Kuchner  Mark Wyatt  Eric Pantin  Anne-Lise Maire  Christophe Vérinaud  Samuel Ronayette  Didier Dubreuil  Michiel Min  Michiel Rodenhuis  Dino Mesa  Russ Belikov  Olivier Guyon  Motohide Tamura  Naoshi Murakami  Ingrid Mary Beerer 《Experimental Astronomy》2012,34(2):355-384

SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets and circumstellar disks in the visible (450?C900 nm) at a spectral resolution of about 40 using both spectroscopy and polarimetry. By 2020/2022, present and near-term instruments will have found several tens of planets that SPICES will be able to observe and study in detail. Equipped with a 1.5 m telescope, SPICES can preferentially access exoplanets located at several AUs (0.5?C10?AU) from nearby stars (<25 pc) with masses ranging from a few Jupiter masses to Super Earths (??2 Earth radii, ??10 M_??) as well as circumstellar disks as faint as a few times the zodiacal light in the Solar System.  相似文献   

Integration of local and scientific knowledge to support drought impact monitoring: some hints from an Italian case study     

Raffaele Giordano  Elisabetta Preziosi  Emanuele Romano 《Natural Hazards》2013,69(1):523-544

According to the Hyogo Framework for Action, increasing resilience to drought requires the development of a people-centered monitoring and early warning system, or in other words, a system capable of providing useful and understandable information to the community at risk. To achieve this objective, it is crucial to negotiate a credible and legitimate knowledge system, which should include both expert and local knowledge. Although several benefits can be obtained, the integration of local and scientific knowledge to support drought monitoring is still far from being the standard in drought monitoring and early warning. This is due to many reasons, that is, the reciprocal skepticism of local communities and decision makers, and the limits in the capacity to understand and assess the complex web of drought impacts. This work describes a methodology based on the sequential implementation of Cognitive Mapping and Bayesian Belief Networks to collect, structure and analyze stakeholders’ perceptions of drought impacts. The methodology was applied to analyze drought impacts at Lake Trasimeno (central Italy). A set of drought indicators was developed based on stakeholders’ perceptions. A validation phase was carried out comparing the perceived indicators of drought and the physical indicators (i.e., Standard Precipitation Index and the level of the lake). Some preliminary conclusions were drawn concerning the reliability of local knowledge to support drought monitoring and early warning.  相似文献   

Defining structural robustness under seismic and simultaneous actions: an application to precast RC buildings     

Domenico Asprone  Raffaele De Risi  Gaetano Manfredi 《Bulletin of Earthquake Engineering》2016,14(2):485-499

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Mainshock-aftershock state-dependent fragility curves: A case of wood-frame houses in British Columbia,Canada     

Lizhong Zhang  Katsuichiro Goda  Flavia De Luca  Raffaele De Risi 《地震工程与结构动力学》2020,49(9):884-903

During a mainshock-aftershock (MSAS) sequence, there is no time to retrofit structures that are damaged by a mainshock; therefore, aftershocks could cause additional damage. This study proposes a new approach to develop state-dependent fragility curves using real MSAS records. Specifically, structural responses before and after each event of MSAS sequences are used to obtain statistical relationships among the engineering demand parameter prior to the seismic event (pre-EDP), the intensity measure of the seismic event (IM), and the engineering demand parameter after the seismic event (post-EDP). The developed fragility curves account for damage accumulation, providing the exceeding probability of damage state (DS) given the IM of the event and the DS of the structure prior to the seismic excitation. The UBC-SAWS model, which was developed for wood-frame houses in British Columbia, Canada, is considered as a case study application. Results indicate that for the examined structural typology, state-dependent fragility curves based on residual interstorey drift ratio (pre-EDP), peak ground velocity (IM), and maximum inter-storey drift ratio (post-EDP) are the best choice to characterise the cumulative damage effect. An illustration of the developed fragility curves is provided by considering a hypothetical MSAS scenario of a M_w 9.0 Cascadia mainshock triggering a M_w 6.0 crustal event in the Leech River fault, affecting wooden houses in Victoria, Canada. The MSAS scenario increases Yellow tags (restricted access) by 12.3% and Red tags (no access) by 4.8%.  相似文献   

Environmental Hazard of Capable Faults: The Case of the Pernicana Fault (Mt. Etna,Sicily     

Azzaro  Raffaele  Ferreli  Luca  Michetti  Alessandro Maria  Serva  Leonello  Vittori  Eutizio 《Natural Hazards》1998,17(2):147-162

When dealing with hazard, the concept of fault capability (the probability of significant surface displacement in the near future) is more useful than the generic and often misleading concept of fault activity. The example of the Pernicana fault, located in the north-eastern flank of the Mt. Etna volcano is used here to illustrate the damage which can be expected in an urbanised area from a capable fault, in this case characterized by 'aseismic creep along part of its length. Along this fault, buildings, roads and other essential lifelines are being affected by slow, left-lateral displacement. The Pernicana fault is only one of a set of structures in the area whose movement, either connected to seismicity or not, is producing severe damage. First identified at the end of the last century, this source of hazard is, nevertheless, still poorly considered by planners and technicians. In Italy fault creep is quite rare outside the Etna region, but fault capability associated with strong earthquakes is relatively frequent, based on historical and palaeoseismological data, and is a feature that should be taken into account for hazard reduction programs.  相似文献   

The absolute magnitude of field metal-poor horizontal branch stars     

Raffaele G. Gratton 《Monthly notices of the Royal Astronomical Society》1998,296(3):739-745

Hipparcos satellite parallaxes for 22 metal-poor field horizontal branch stars with V ₀<9 are used to derive their absolute magnitude. The weighted mean value is M_V =+0.69±0.10 for an average metallicity of [Fe/H]=−1.41; a somewhat brighter average magnitude of M_V =+0.60±0.12 for an average metallicity of [Fe/H]=−1.51 is obtained by eliminating HD 17072, which might be on the first ascent of the giant branch rather than on the horizontal branch. The present values agree with the determinations based on proper motions and application of the Baade–Wesselink method to field RR Lyraes; they are 0.1–0.2 mag fainter than those based on calibration of cluster distances obtained by using local subdwarfs and on alternative distance calibrators for the Large Magellanic Cloud (LMC). The possibility that there is a real difference between the luminosity of the horizontal branch for clusters and the field is briefly commented on.  相似文献   

The magnetohydrodynamic turbulent cascade in the ecliptic solar wind: Study of Ulysses data   总被引：1，自引：0，他引：1  

Raffaele Marino  Luca Sorriso-Valvo  Pierluigi Veltri  Roberto Bruno 《Planetary and Space Science》2011,59(7):592-597

The occurrence of a nonlinear turbulent energy cascade in solar wind plasma has been recently established through the observation of an exact law from spacecraft measurements. The main results obtained in the fast, polar wind measured by Ulysses spacecraft are reviewed here. In particular, the turbulent cascade is seen as the mean to provide the energy necessary for the local heating in the non-adiabatic expansion of the solar wind. The importance of the density fluctuations in enhancing the turbulent energy transport is also evidenced. The ecliptic wind data measured by Ulysses are studied here in the same framework. This has been done by separating fast and slow streams, in order to avoid mixing of different physical conditions. The results further support the need for separate analysis of the two types of wind.  相似文献