88,289 research outputs found
Simulating radiometric observations of cylindrically-shaped precipitation along Earth-satellite microwave links
No full text
Simulation of radiometric and attenuation measurements along earth-satellite links in the 10- to 50- GHz band through horizontally-finite convective raincells
No full textAn iterative solution is illustrated of the three-dimensional radiative transfer
equation for a horizontally finite and vertically inhomogeneous precipitating cloud. The
method is applied to modeling a convective rain cell of cylindrical shape, characterized by
spherical raindrops having a negative-exponential drop size distribution. The realistic
model also takes into account the presence of a cloud and an ice layer above the rain cell
itself. The simulated brightness temperature, the mean radiative temperature, and the
path attenuation are evaluated in a three-dimensional geometry from a surface
observation point in order to simulate a ground-based station with a beacon receiver and
a multichannel radiometer. Numerical results are shown to illustrate the potential of the
proposed model for different sets of frequency channels, observation geometries, cloud
sizes and types, and precipitation intensities. After generating a large data set by varying
the relevant rain cell parameters, regression analysis is applied to derive a statistical
estimation of the total path attenuation from surface rain rate and ground-based
radiometric measurements together with the frequency scaling factors for cumuliform
clouds in the 10- to 50-GHz band
On the use of ground-based multi-frequency microwave radiometer for precipitation and radio-propagation parameter retrieval
No full textNeural-network approach to ground-based passive microwave estimation of precipitation intensity and extinction
No full textA physically-based passive microwave technique is proposed to estimate precipitation intensity and extinction from ground. Multi-frequency radiometric measurements are inverted to retrieve surface rain rate, columnar precipitation contents and rainfall microwave extinction. A new inversion methodology, based on an artificial neurat-network feed-forward algorithm, is evaluated and compared against a previously developed regression technique. Both retrieval techniques are trained by numerical simulations of a radiative transfer model applied to microphysically-consistent precipitating cloud structures. Cloud microphysics is characterized by using parameterized hydrometeor drop size distribution, spherical particle shape and dielectric composition. The radiative transfer equation is solved for plane-parallel seven-layer structures, including liquid, melted, and ice spherical hydrometeors. The proposed neural-network inversion technique is tested and compared with the regression algorithm on synthetic data in order to understand their potential and to select the best frequency set for rainfall rate, columnar contents and extinction estimation. Available ground-based radiometric measurements at 13.0, 23.8, and 31.6 GHz are used for experimentally testing and comparing the neural-network retrieval algorithm. Comparison with rain gauge data and rain extinction measurements, derived from three satellite beacon channels at 18.7, 39.6, and 49.5 GHz acquired at Pomezia (Rome, Italy), are performed and discussed for a selected case of light-to-moderate rainfall. (c) 2005 Elsevier B.V. All rights reserved
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Lo sciopero contro le guerre come forma di accoglienza. Riflessioni introduttive a un’inchiesta sulla solidarietà operaia.
No full textAlso By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
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