1,720,986 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Thermal Tests Of A CP5.2 Packaging System: Post Experimental Test Description
No full textManaging radioactive waste must be carried out within a strict framework and with a constant
requirement to protect human beings and the environment. A safety management of the radioactive
material or waste (RAM or RW) unavoidably involves transportation activities by using robust safe and
reliable packaging system.
The integrity is a crucial aspect in the design of these systems; to certify it packages should demonstrate
to withstand loads, that could occur under normal and accident conditions, and to meet the safety
requirements in terms of performances of containment and radiation protection, like the IAEA ones.
This study deals with the thermal performances of an Italian CP5.2 packaging system aimed at the
transportation of bituminised wastes, which have been evaluated by executing experimental tests in the
fire scenario as specified in the IAEA regulations (i.e. engulfing fire of 800 °C for 30 minutes).
To the purpose a dedicated small scale mock-up has been designed and built at the Dept. DICI of the
University of Pisa. The experimental test allowed to set up the test procedure to be adopted for the fire
tests of a large scale system in consideration of risk related to the stowed bituminised wastes.
The results of the thermal test are presented and discussed.
Analysing them it is possible to conclude that the overall integrity of the packaging system is assured
Post-metering value-added services for low voltage electricity users: Lessons learned from the Italian experience of CHAIN 2
Get PDFElectrical energy consumption data accessibility for low voltage end users is one of the pillars of smart grids. In some countries, despite the presence of smart meters, a fragmentary data availability and/or the lack of standardization hinders the creation of post-metering value-added services and confines such innovative solutions to the prototypal and experimental level. We take inspiration from the technology adopted in Italy, where the national regulatory authority actively supported the definition of a solution agreed upon by all the involved stakeholders. In this context, smart meters are enabled to convey data to low voltage end users through a power line communication channel (CHAIN 2) in near real-time. The aim of this paper is twofold. On the one hand, it describes the proof of concept that the channel underwent and its subsequent validation (with performances nearing 99% success rate). On the other hand, it defines a classification framework (I^2MA) for post-metering value-added services, in order to categorize each use case based on both level of service and expected benefits, and understand its maturity level. As an example, we apply the methodology to the 16 use cases defined in Italy. The lessons learned from the regulatory, technological, and functional approach of the Italian experience bring us to the provision of recommendations for researchers and industry experts. In particular, we argue that a well-functioning post-metering value-added services' market can flourish when: i) distribution system operators certify the measurements coming from smart meters; ii) national regulatory authorities support the technological innovation needed for setting up this market; and iii) service providers create customer-oriented solutions based on smart meters' data
THERMAL TESTS OF A CP5.2 PACKAGING SYSTEM: PROTOTYPE AND EXPERIMENTAL TEST DESCRIPTION
No full textManaging radioactive waste must be carried out within a strict framework and with a constant
requirement to protect human beings and the environment. A safety management of the radioactive
material or waste (RAM or RW) unavoidably involves transportation activities by using robust safe and
reliable packaging system.
The integrity is a crucial aspect in the design of these systems; to certify it packages should demonstrate
to withstand loads, that could occur under normal and accident conditions, and to meet the safety
requirements in terms of performances of containment and radiation protection, like the IAEA ones.
This study deals with the thermal performances of an Italian CP5.2 packaging system aimed at the
transportation of bituminised wastes, which have been evaluated by executing experimental tests in the
fire scenario as specified in the IAEA regulations (i.e. engulfing fire of 800 °C for 30 minutes).
To the purpose a dedicated small scale mock-up has been designed and built at the Dept. DICI of the
University of Pisa. The experimental test allowed to set up the test procedure to be adopted for the fire
tests of a large scale system in consideration of risk related to the stowed bituminised wastes.
The results of the thermal test are presented and discussed.
Analysing them it is possible to conclude that the overall integrity of the packaging system is assured
Orbit determination for the radio science experiment of the NASA mission Juno
Get PDFJuno is a NASA New Frontiers mission to the planet Jupiter, launched from Cape Canaveral on August 5,
2011. The spacecraft will arrive to Jupiter in 2016 and will be placed for one year in a polar high-eccentric
orbit to study the composition of the planet, the gravity and the magnetic field, and the magnetosphere. The
Italian Space Agency (ASI) contributed to the mission providing the radio science instrument KaT (Ka-Band
Translator, developed by the University of Rome “La Sapienza” and Thales Alenia Space) used for the gravity
experiment, which has the goal of studying the Jupiter’s deep structure by mapping the planet’s gravity. Such
instrument takes advantage of synergies with a similar tool in development for BepiColombo, the ESA cornerstone
mission to Mercury. The Celestial Mechanics Group of the University of Pisa and SpaceDyS s.r.l. are responsible,
under an ASI contract, for the development of an orbit determination and parameters estimation software for
processing the real data independently from NASA software ODP. We shall present the state of the art of such
software highlighting the theoretical models used, the problems addressed and first results about the scientific
goals obtained with simulated data
Gravimetry, rotation and angular momentum of Jupiter from the Juno Radio Science experiment
No full textJuno is a NASA space mission to Jupiter, arriving at the planet in July 2016. Through accurate Doppler tracking in X and Ka-band, the Radio Science experiment will allow to map Jupiter's gravity field, crucial for the study of the interior structure of the planet. In this paper we describe the results of numerical simulations of this experiment, performed with the ORBIT14 orbit determination software, developed by the Department of Mathematics of the University of Pisa and by the spin-off Space Dynamics Services srl. Our analysis included the determination of Jupiter's gravity field, the Love numbers, the direction of the rotation axis and the angular momentum magnitude, the latter by measuring the Lense-Thirring effect on the spacecraft. As far as the gravity field is concerned, the spherical harmonics coefficients of Jupiter's gravitational potential are highly correlated and the accuracy in the determination of the zonal coefficients of degree l is degraded for l>15l>15. We explore the possibility of using a local model, introducing ring-shaped mascons, so as to determine the gravity field of the portion of the spherical surface bounded by latitudes 6°N and 35°N, the latitude belt observed during Juno's pericenter passes. Finally, the determination of Jupiter's angular momentum magnitude turned out to be compromised by the impossibility of separating the effects of the Lense-Thirring acceleration and of a change in Jupiter's rotation axis direction
On the Juno Radio Science Experiment: models, algorithms and sensitivity analysis
Get PDFJuno is a NASA mission launched in 2011 with the goal of studying Jupiter. The probe will arrive to the planet in 2016 and will be placed for one year in a polar high-eccentric orbit to study the composition of the planet, the gravity and the magnetic field. The Italian Space Agency (ASI) provided the radio science instrument KaT (Ka-Band Translator) used for the gravity experiment, which has the goal of studying the Jupiter's deep structure by mapping the planet's gravity: such instrument takes advantage of synergies with a similar tool in development for BepiColombo, the ESA cornerstone mission to Mercury. The Celestial Mechanics Group of the University of Pisa, being part of the Juno Italian team, is developing an orbit determination and parameters estimation software for processing the real data independently from NASA software ODP. This paper has a twofold goal: first, to tell about the development of this software highlighting the models used, second, to perform a sensitivity analysis on the parameters of interest to the mission
Variations on the Author
Get PDF“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
Get PDFWe 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
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