1,721,076 research outputs found
La sapienza ispirata dalla religione : pitture nella Sala degli Esperimenti nel Collegio delle Scuole Pie Fiorentine.
No full text"Pubblicata per la solenne apertura di detta sala Accademica in occasione de' pubblici Esperimenti, dati dagli Scolari delle Scuole Pie di Firenze dal di 3 Settembre 1838 al di 12 dello stesso mese."--Colophon.Text signed: Paolo Sarti [p. 6] and P. Tanzini [p. 16].Mode of access: Internet
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Surveying co-located space-geodetic instruments for ITRF computation
No full textAbstract. A new and comprehensive method is presented
that can be used for estimating eccentricity vectors
between global positioning system (GPS) antennas,
doppler orbitography and radiopositioning integrated
by satellites (DORIS) antennas, azimuth-elevation
(AZ-EL) very long baseline interferometry (VLBI) telescopes,
and satellite laser ranging (SLR) and lunar laser
ranging (LLR) telescopes. The problem of reference
point (RP) definition for these space-geodetic instruments
is addressed and computed using terrestrial
triangulation and electronic distance measurement
(EDM) trilateration. The practical ground operations,
the surveying approach and the terrestrial data processing
are briefly illustrated, and the post-processing procedure
is discussed. It is a geometrically based analytical
approach that allows computation of RPs along with a
rigorous statistical treatment of measurements. The tight
connection between the geometrical model and the
surveying procedure is emphasized. The computation
of the eccentricity vector and the associated variance–
covariance matrix between an AZ-EL VLBI telescope
(with or without intersecting axes) and a GPS choke ring
antenna is concentrated upon, since these are fundamental
for computing the International Terrestrial Reference
Frame (ITRF). An extension to RP computation and
eccentricity vectors involving DORIS, SLR and LLR
techniques is also presented. Numerical examples of the
quality that can be reached using the authors’ approach
are given. Working data sets were acquired in the years
2001 and 2002 at the radioastronomical observatory of
Medicina (Italy), and have been used to estimate two
VLBI-GPS eccentricity vectors and the corresponding
SINEX files
Introduction to the Proceedings of WGTTG2021
Full text linkWe describe the Italy-South Africa Research Program 2018–2020, focusing on the mobility scheme “Algebraic Graph Theory and Complex Networks” which supported a series of scientific initiatives between the University of Cape Town (Cape Town, South Africa) and the University of Naples Federico II (Naples, Italy) during the years 2018–2021. We sketch the relevant steps of the collaboration, focusing on the creation of a network of researchers between Italy and South Africa in the fields of Graph Theory and Combinatorics. In this context it becomes more relevant the role of the “Workshop on Graphs, Topology and Topological Groups 2021” and of the corresponding proceedings
Gravity-dependent signal path variation in a large VLBI telescope modelled with combination of surveying methods
No full textThe very long baseline interferometry (VLBI)
antenna in Medicina (Italy) is a 32-m AZ-EL mount that
was surveyed several times, adopting an indirect method, for
the purpose of estimating the eccentricity vector between the
co-locatedVLBIand Global Positioning System instruments.
In order to fulfill this task, targets were located in different
parts of the telescope’s structure. Triangulation and trilateration
on the targets highlight a consistent amount of deformation
that biases the estimate of the instrument’s reference
point up to 1 cm, depending on the targets’ locations. Therefore,
whenever the estimation of accurate local ties is needed,
it is critical to take into consideration the action of gravity on
the structure. Furthermore, deformations induced by gravity
on VLBI telescopes may modify the length of the path
travelled by the incoming radio signal to a non-negligible
extent. As a consequence, differently from what it is usually
assumed, the relative distance of the feed horn’s phase
centre with respect to the elevation axis may vary, depending
on the telescope’s pointing elevation. TheMedicina telescope’s
signal path variationL increases by a magnitude of
approximately 2 cm, as the pointing elevation changes from
horizon to zenith; it is described by an elevation-dependent
second-order polynomial function computed as, according to
Clark and Thomsen (Techical report, 100696,NASA, Greenbelt,
1988), a linear combination of three terms: receiver displacement dR, primary reflector’s vertex displacement dV and focal length variations dF. dL was investigated
with a combination of terrestrial triangulation and trilateration,
laser scanning and a finite element model of the antenna.
The antenna gain (or auto-focus curve)G is routinely determined
through astronomical observations. A surprisingly
accurate reproduction of dG can be obtained with a combination
of dV, dF and dR
Introduction to the Proceedings of WGTTG2021
No full textWe describe the Italy-South Africa Research Program 2018–2020, focusing on the mobility scheme ``Algebraic Graph Theory and Complex Networks'' which supported a series of scientific initiatives between the University of Cape Town (Cape Town, South Africa) and the University of Naples Federico II (Naples, Italy) during the years 2018–2021. We sketch the relevant steps of the collaboration, focusing on the creation of a network of researchers between Italy and South Africa in the fields of Graph Theory and Combinatorics. In this context it becomes more relevant the role of the ``Workshop on Graphs, Topology and Topological Groups 2021'' and of the corresponding proceedings
Variations on the Author
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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