1,720,956 research outputs found
Modelling time to university dropout by means of time-dependent frailty COX PH models = Modelli di COX tempo-dipendenti con frailty per la modellizzazione del tempo all’abbandono universitario
No full textIl dropout universitario `e un fenomeno studiato in tutto il mondo, con
l’obiettivo di caratterizzarlo e prevenirlo. In questo studio, analizziamo il tempo
all’abbandono univeristario, seguendo un approccio di analisi di sopravvivenza.
Analizziamo le carriere di 50,000 studenti immatricolati in 18 corsi di studio di In-
gegneria del Politencico di Milano. Viste le potenziali differenze nelle determinanti
del dropout nel tempo e la struttura annidata dei dati, applichiamo un modello di
COX che include covariate tempo-dipendenti, per tracciare la carriera degli stu-
denti nel tempo, e una frailty, per modellizzare la variabilit`a tra corsi di studio. La
forza del metodo proposto `e duplice: descrivere le dinamiche del dropout nel tempo
e identificare un giusto trade-off tra una previsione accurata e una previsione pre-
coce.University dropout is studied worldwide, with the aim of identifying its
determinants and of preventing it. In this study, we model and predict the time to
dropout of university students, following a survival analysis approach. We analyse
data about 50,000 students, enrolled in 18 different bachelor of science in Engineer-
ing at Politencico di Milano. Given the potential heterogeneity in the dropout deter-
minants over time and the two-levels structure of the data (students nested within
degree programmes), we applying a Cox PH model that includes time-varying co-
variates, to track students careers over time, and a frailty, to take into account the
heterogeneity across degree programmes. The strength of the method is twofold:
to describe the dropout over time and to identify a good trade-off between a high
prediction accuracy and the development of an early warning system
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
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
Modelling time-to-dropout via shared frailty Cox models. A trade-off between accurate and early predictions
Full text linkThis paper investigates the student dropout phenomenon in a technical Italian university from a time-to-event perspective. Shared frailty Cox time-dependent models are applied to analyse the careers of students enrolled in different engineering programs with the aim of identifying the determinants of student dropout through time, predicting the time to dropout as soon as possible and to observe how the dropout phenomenon varies across time and degree programs. The innovative contributions of this work are methodological and managerial. First, the adoption of shared frailty Cox models with time-varying covariates is relatively new to the student dropout literature and it allows to consider the student career evolution and the heterogeneity across degree programs. Second, understanding the dropout pattern over time and identifying the earliest moment for obtaining its accurate prediction allow policy makers to set timely interventions for students at risk of dropout
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
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
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