1,721,184 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
Toward a unified account of nonsymbolic and symbolic representations of number: Insights from a combined psychophysical-computational approach
No full textThere is an ongoing, vibrant debate about whether numerical information in both nonsymbolic and symbolic notations would be supported by different neurocognitive systems or rather by a common preverbal approximate number system, which is ratio dependent and follows Weber’s law. Here, we propose that the similarities between nonsymbolic and symbolic number processing can be explained based on the principle of efficient coding. To probe this hypothesis we employed a new empirical approach, by predicting the behavioural performance in number comparison tasks with symbolic (i.e., number words) and nonsymbolic (i.e., arrays of dots) information not only from numerical ratio, but for the first time also from natural language data. That is, we used data extracted from vector-space models that are informative about the distributional pattern of number-words usage in natural language. Results showed that linguistic estimates predicted the behavioural performance in both symbolic and nonsymbolic tasks. However, and critically, our results also showed a task-dependent dissociation: linguistic data better predicted the performance in the symbolic task, whereas real numerical ratio better predicted the performance in the nonsymbolic task. These findings indicate that efficient coding of environmental regularities is an explanatory principle of human behavior in tasks involving numerical information. They also suggest that the ability to discriminate a stimulus from similar ones varies as a function of the specific statistical structure of the considered learning environment
Optimising the quality of an SfM-MVS slope monitoring system using fixed cameras
No full textThe quality of 3D scene reconstruction and monitoring through structure-from-motion multiview stereo (SfM-MVS) depends on critical key factors, including camera calibration and image network geometry. The goal of this paper is to examine the monitoring ability of an SfM-MVS workflow based on four or more ground-based digital single-lens reflex (DSLR) cameras and to estimate differences when adopting both fixed and variable camera positions and orientations. This was achieved by conducting work on a scaled laboratory testfield and a sea cliff. Tests demonstrate that a monitoring system using just four fixed cameras can achieve valuable monitoring capabilities and tolerate imperfections in the camera calibration. Furthermore, such a configuration can achieve accuracies comparable to terrestrial laser scanning (TLS) and drone-based photogrammetry. The study demonstrates that minimising registration errors between point clouds is critical. The “registration SIFT” approach could resolve such problems
A fiber beam element based on plastic and damage models for prestressed concrete structures
No full textModeling of prestressed concrete beams and their degrading processes are relevant issues in the assessment of existing structures and infrastructures, particularly for bridges. This work focuses on the formulation and validation of a fiber beam finite element for prestressed concrete structural elements that accounts for nonlinear material behavior and time-dependent phenomena. The element is a 3D Timoshenko beam that follows a force-based approach. A fiber discretization of the cross-section is used to model concrete, steel reinforcements and prestressing cables based on damage and plasticity for concrete, and plasticity for steel through three-dimensional constitutive laws. The steel fibers are fully bonded. Strain-softening in the concrete requires an appropriate regularization procedure. The tendons are treated as additional fibers with prestressing applied as initial strain of the relevant fibers. No additional discretization is required except for the description of the tendons’ profile. Time-dependent phenomena such as creep, shrinkage and cable relaxation are taken into account. The proposed model is implemented in the OpenSees computational framework to carry out specific validation tests and demonstrate the element potential
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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