1,721,190 research outputs found
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
Modelling Heavy Tailed Phenomena Using a LogNormal Distribution Having a Numerically Verifiable Infinite Variance
Full text linkOne-sided heavy tailed distributions have been used in many engineering applications,
ranging from teletraffic modelling to financial engineering. In practice, the most interesting heavy
tailed distributions are those having a finite mean and a diverging variance. The LogNormal
distribution is sometimes discarded from modelling heavy tailed phenomena because it has a finite
variance, even when it seems the most appropriate one to fit the data. In this work we provide for
the first time a LogNormal distribution having a finite mean and a variance which converges to a
well-defined infinite value. This is possible thanks to the use of Non-Standard Analysis. In particular,
we have been able to obtain a Non-Standard LogNormal distribution, for which it is possible to
numerically and experimentally verify whether the expected mean and variance of a set of generated
pseudo-random numbers agree with the theoretical ones. Moreover, such a check would be much
more cumbersome (and sometimes even impossible) when considering heavy tailed distributions in
the traditional framework of standard analysis
Dati sulla urbanizzazione italiana: verso la terza generazione
No full textIn this current period, several attempts to classify the “made artificial” areas are occurring and
tend to identify the categories on which match the amount of adverse environmental deterioration.
Today the “institutional” database does not exist in appropriate scales that can provide an
official fact, uniform and reliable, whereas there are a number of methodologies and information
from scientific sources and pseudo such.Sono attualmente in corso diversi tentativi di classificazione delle superfici “artificializzate” che
tendono ad individuare le categorie alle quali poi far corrispondere i numerosi effetti ambientali
deteriori. Ad oggi non esistono “database “istituzionali” a scale adeguate che possano fornire
un dato ufficiale, omogeneo e attendibile, mentre c’è invece una discreta proliferazione di informazioni
provenienti da metodologie e fonti scientifiche e pseudo tali
Patient’s consent to central venous catheterization
No full textThe need to obtain a patient's consent for his health care is a principle set out in the Italian Constitution, which safeguards a person's right to health. Articles 13 and 32.2 confirm a person's freedom and the right to make free decisions about one's medical treatment. Nobody must be obliged to any medical procedure, unless as by law enacted. The obligation to inform patients is important during the contractual phase: consent is an essential element in the professional contract governing the relationship between a physician and a patient. The former is obligated to inform the latter about his medical intervention clearly and precisely, to enable the patient to decide freely whether to undergo a medical procedure. At this point, it is also essential to obtain a patient's consent for those treatments that although they are carried out in a correct and careful way, could damage a person's physical integrity. The failure to obtain consent could give rise to a burden of responsibility on behalf of the clinician. A central venous catheterization in hemodialysis (HD) is a common procedure performed during routine nephrological treatments. Our signed informed consent form prior to introducing a central venous catheter is thought to satisfy requirements provided for in current regulations to give correct information
Extending the Applicability of the Pollaczek-Khinchin Formula to the Case of Infinite Service Moments
No full textIn teletraffic engineering, M/G/1 queues are pivotal for optimizing network performance and operational efficiency. Closed formulas like the mean-value Pollaczek-Khinchin (MV-PK) are highly valued by practitioners due to their simplicity, facilitating rapid and flexible system analyses. This formula aids in verifying the reliability of complex simulations concerning M/G/1 models, especially when applicable. The challenge intensifies when dimensioning M/G/1 systems with heavy-tailed service time distributions. Simulation of such queues becomes notably arduous, necessitating increased number of samples and longer simulation durations. Moreover, verification becomes more intricate as the MV-PK formula cannot be straightforwardly applied in such cases. This paper extends the MV-PK formula to heavy tailed service distributions with infinite/infinitesimal moments using Nonstandard Analysis. Additionally, it shows how recently introduced Bounded Algorithmic Numbers (BANs) enables numerical verification of the extended PK formula via discrete-event simulations of the M/G/1 queue, even when predicted delay values are infinite. The implemented approach tends to converge fast and exhibits remarkable numerical robustness. It adheres to the principle of 'write once, run multiple times", as the same source code for queue simulation handles both finite and infinite variance cases
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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