1,720,957 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
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
ROUTING SWITCH SPACEWIRE: SVILUPPO DI UN AMBIENTE UVM PER LA VERIFICA FUNZIONALE E PROGETTAZIONE DI NUOVE CARATTERISTICHE PREVISTE DALLO STANDARD
No full textEra il 4 ottobre 1957 quando il lancio del satellite Sputnik 1 a opera dell'URSS aprì l'era dell'esplorazione spaziale. Si trattava di una piccola sfera di alluminio che conteneva solo alcune batterie, un termometro e un paio di trasmittenti. Da allora il numero di missioni scientifiche ha visto una continua crescita, coinvolgendo strumentazioni e tecnologie sempre più sofisticate (radiometri, termocamere, fotocamere, ...) e producendo quantità di dati progressivamente maggiori. Si tratta di informazioni preziose che necessitano ovviamente di essere gestite adeguatamente.
Questa esigenza e il bisogno di integrare a bordo dei satelliti strumenti eterogenei in numero costantemente crescente, nel modo più efficace possibile in termini di tempo, costi, affidabilità e riusabilità, hanno portato alla nascita dello standard SpaceWire, promosso dall'European Space Agency (ESA), con la collaborazione di agenzie spaziali nazionali, industrie europee e università.
Lo SpaceWire è un protocollo di comunicazione seriale le cui caratteristiche (elevate velocità di trasmissione, bassa tensione/potenza, immunità ai disturbi, flessibilità architetturale, ...) lo rendono ideale per strutturare le interconnessioni e in generale il networking fra strumenti, memorie di massa, processori, trasmettitori di telemetrie e altri elementi di bordo dei satelliti. Dalla sua prima pubblicazione, nel gennaio 2003, lo standard SpaceWire è stato adottato dalle principali agenzie spaziali mondiali (ESA, NASA, JAXA, Roscosmos) e trova impiego oggi in centinaia di satelliti scientifici e commerciali.
Ai link punto-punto, lo standard SpaceWire affianca i routing switch, dispositivi estremamente versatili che consentono l'interconnessione di numerosi componenti facendo uso di un ridotto numero di cablaggi e porte, contenendo peso e costi, e rendendo possibile la riconfigurabilità della rete via software, anche da remoto.
Questo lavoro di tesi si concentra sulla macrocella di un Routing Switch SpaceWire, ponendosi come obiettivi l'ottimizzazione della sua architettura, la progettazione di nuove caratteristiche derivanti dalla nuova versione dello standard e, soprattutto, lo sviluppo di un ambiente avanzato per la verifica funzionale, caratterizzato dalla generazione casuale vincolata degli stimoli e dal controllo automatico delle uscite. In particolare, l'ambiente di verifica si basa sullo standard Universal Verification Methodology (UVM), raccolta delle più recenti tecniche di test condivise dalla maggior parte delle aziende operanti nel settore dell'elettronica digitale integrata. Premessa per la realizzazione dello strumento di verifica è stata la stesura di un verification plan dettagliato, definito a partire dalle specifiche imposte dallo standard e quindi dall'estrazione dei requisiti funzionali. L'attività è proseguita con l'esecuzione intensiva dei test implementati, la risoluzione di tutti i problemi emersi nel design del Ruting Switch e l'implementazione preliminare della macrocella sulla tecnologia FPGA maggiormente impiegata per i sistemi digitali nelle missioni spaziali.
Nel primo capitolo vengono riportati, in maniera sintetica, alcuni aspetti basilari dello standard SpaceWire: possibile architettura di rete, caratteristiche dei collegamenti, codifiche, formato dei pacchetti e proprietà dei routing switch. Sono inoltre descritte le differenze introdotte con la nuova versione dello standard.
Il secondo capitolo illustra in dettaglio l'architettura del Routing Switch e il funzionamento dei vari moduli che ne fanno parte, focalizzando l'attenzione sulle principali innovazioni apportate al design.
La prima parte del terzo capitolo è dedicata a introdurre la verifica funzionale in termini di approcci, criticità e metodologie. Nella seconda parte del capitolo viene invece descritto il verification plan redatto e, a seguire, l'ambiente di verifica sviluppato, con particolare riguardo alle strategie adottate per analizzare e confrontare le uscite.
I principali risultati ottenuti durante i test del Routing Switch sono riassunti e commentati nel capitolo quattro, che termina con i report relativi a una sintesi preliminare del design e a un'implementazione su FPGA radiation tolerant RTAX1000S, device certificato per lo spazio, approvato da ESA e largamente impiegato a bordo di numerosi satelliti scientifici
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Advanced methodologies for verification of systems-on-chip involved in satellite applications
No full textIn recent years, unprecedented technological advancements in electronics have enabled increasingly powerful boards and components, allowing for progressively higher data processing speeds. This trend has also been mirrored in space electronics, where more complex systems are being developed and integrated onboard satellites.
Specifically, both inter-unit communications within satellites and data processing systems have reached speeds previously unseen, theoretically up to several tens of Gigabits per second. Unfortunately, this progress has not extended to the methodologies used to test these systems, thereby posing a potential risk to onboard operations and, in some cases, to the entire mission. Verification and validation phases for digital systems in satellite telecommunications are often underestimated and incompletely executed, primarily due to high engineering costs that are difficult to amortize given the low production volume.
This thesis aims to address this gap by proposing effective and highly flexible strategies for both functional verification and hardware validation of complex systems, specifically targeting satellite communications applications.
For functional verification, the proposed strategy focuses on the development of advanced, automated verification environments following the Universal Verification Methodology (UVM) framework, currently the state-of-the-art standard for this application. Specifically, software models known as Digital Twins are proposed for integration into the verification environments to emulate the ideal behavior of a real system. This solution offers high flexibility and simplifies and automates the verification flow: the Digital Twin can produce the expected behavior of the system under test, allowing for comparison
with the real system’s output. Additionally, it can facilitate data transmission and reception by establishing direct communication with the design under verification. This approach was applied in verification campaigns for various highly complex systems used in different applications, covering onboard satellite communication (SpaceWire protocol) and data processing for ground transmission, supporting both optical and radio-frequency communications (encoding and modulation systems compliant with CCSDS 131.2-B and CCSDS 142.0-B standards). This served as a demonstration of
the effectiveness and flexibility of this methodology, proving its applicability to the space sector.
The second part of the thesis presents a validation strategy for systems capable of generating data at several Gigabits per second after their implementation on hardware boards, again focusing on satellite applications. This strategy demonstrates how, by equipping the system under validation with high-speed interfaces and using Electrical Ground
Support Equipment (EGSE), it is possible to test the system without limiting performance or losing data. To validate the data produced by the system under test, Digital Twins are proposed once more, which can generate the expected data outputs. Two validation campaigns based on this strategy are presented for two very different systems: the first is a demonstrator consisting of a chain of three electronic boards that act respectively as a transmitter, communication channel emulator, and receiver. This setup is used to evaluate the performance of the CCSDS 131.2-B protocol, defined
for satellite-to-ground data transmission, based on configurable characteristics of orbit, satellite, and communication channel. This protocol is particularly relevant for Earth observation missions, especially the European Space Agency’s Copernicus missions. The second system is an optical Encoder and Modulator compliant with the CCSDS 142.0-B standard, which defines two distinct processing protocols: High Photon Efficiency (HPE) and Optical-On-Off Keying (O3K). These protocols achieve transmission speeds of up to 8 and 10 Gigabits per second, respectively.
The research presented in this thesis was conducted in collaboration with IngeniArs S.r.l. as part of the Industrial Doctorate, with the aim of developing advanced methodologies for verifying digital designs used in satellite applications. The ultimate objective of this manuscript is to demonstrate the potential, applicability, and sustainability of the proposed methodologies within industrial projects
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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