1,721,184 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
Numerical representations of a universal subspace flow for linear programs
No full textIn 1991, Sonnevend, Stoer, and Zhao [Math. Programming 52 (1991) 527--553] have shown that the central paths of strictly feasible instances of linear programs generate curves on the Grassmannian that satisfy a universal ordinary differential equation. Instead of viewing the Grassmannian as the set of all projection matrices of rank , we view it as the set of all full column rank matrices, quotiented by the right action of the general linear group . We propose a class of flows in that project to the flow on the Grassmannian. This approach requires much less storage space when (i.e., there are many more constraints than variables in the dual formulation). One of the flows in , that leaves invariant the set of orthonormal matrices, turns out to be a particular version of a matrix differential equation known as Oja's flow. We also point out that the flow in the set of projection matrices admits a double bracket expression
Continuous-time systems that solve computational problems
No full textThe concept of using continuous-time dynamical systems (described by ordinary differential equations) in order to solve computational problems is discussed, with an emphasis on convergence analysis and design procedures. The continuous-time approach is illustrated on concrete examples related to the computation of eigenvalues and eigenvectors of matrices
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
Atrial fibrillation : detection of atrial rate and prediction during catheter ablation
No full textThis thesis treats of the problematic of patients with atrial fibrillation who undergo a catheter ablation. It comports two main objectives. The first one is to implement an algorithm capable of compute the atrial rate of a patient during the procedure from the detection of the A peaks on the patient's atrial rhythm signal. The second one is to find a way to predict the catheter ablation outcome (i.e. the absence of recurrence of the pathology) from the patient's characteristics. An empirical method has been implemented to detect the atrial rate, since the traditional frequency-based methods were unsuccessful. This method is based on finding the peaks of a signal and keeping the ones with some specificities. Those are determined by three parameters: the minimum height, the minimum peak separation and the minimum peak prominence. The first parameter is fixed, while the two other ones have to be selected. The user can either find these parameters manually (which gives a very good result) or use a suggested set of parameters (which can either give a good result or lead to a very big error). The learning has been conducted on 66 patients and 45 features. Among these features, the atrial rate and the maximum AA interval could not have been used, since those data where highly incomplete. Three algorithms have been considered: CART algorithm, Random Forest algorithm or -Nearest Neighbours algorithm. The feature selection has been produced by two different methods: ReliefF and mutual information. Only the CART algorithm was able to output acceptable results with a BCR =0.73, while the other algorithms were not satisfying at all, giving BCR near 0.5 (total uncertainty)Master [120] : ingénieur civil en mathématiques appliquées, Université catholique de Louvain, 201
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
A new statistical framework for testing association of genetic variants within Highlander
No full textThe purpose of this master's thesis is the implementation of a new statistical framework based on the SKAT package, developed at Harvard, supporting the main class of association tests that have been developed nowadays (Burden, SKAT and SKATO). The framework has been developed in order to be used within Highlander, a software developed at GEHU lab that centralizes all their variant data and annotations from NGS (Next Generation Sequencing, mainly Whole Exome Sequencing). The purpose of this framework will be to fasten and guide the investigator through the identification of genetic regions (e.g. genes) which are most likely to be involved in rare diseasesMaster [120] : ingénieur civil en mathématiques appliquées, Université catholique de Louvain, 201
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