1,721,049 research outputs found
Numerical assessment of the ROI CT problem in fan-beam geometries
No full textWe deal with some algorithms for solving the region-of-interest (ROI) problem in computed tomography. This is a challenging problem, currently receiving increasing attention due to the wide range of applications in biomedical imaging. We consider diferent regularization approaches, also based on shearlets, to solve the related optimization problem and we compare their pros and cons. The results of extensive numerical experiments on simulated as well as real data will give some assessments on the dependence of the inal reconstructions on the ROI size and position, in the case of fan-beam CT
Quantitative methods in ocular fundus imaging: Analysis of retinal microvasculature
No full textSeveral diseases including diabetes, hypertension and glaucoma are known to cause alterations in the human retina that can be visualized non-invasively and in vivo using well established techniques of fundus photography. Since the treatment of these diseases can be significantly improved with early detection, methods for the quantitative analysis of fundus imaging have been the subject of extensive studies. Following major advances in image processing and machine learning during the last decade, a remarkable progress is being made towards developing automated quantitative methods to identify image-based bio-markers of different pathologies. In this paper, we focus especially on the automated analysis of alterations of retinal microvasculature - a class of structural alterations that is particularly important for early detection of cardiovascular and neurological diseases
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
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Mini-Workshop: Shearlets
Full text linkOver the last 20 years, multiscale methods and wavelets have revolutionized the field of applied mathematics by providing an efficient means for encoding isotropic phenomena. Directional multiscale systems, particularly shearlets, are now having the same dramatic impact on the encoding of multivariate signals. Since its introduction about five years ago, the theory of shearlets has rapidly developed and gained wide recognition as the superior way of achieving a truly unified treatment in both the continuum and digital setting. By now, shearlet analysis has reached maturity as a research field, with deep mathematical results, efficient numerical methods, and a variety of high-impact applications. The main goal of the Mini-Workshop Shearlets was to gather the world’s experts in this field in order to foster closer interaction, attack challenging open problems, and identify future research directions
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
Pseudodifferential Operators on Modulation Spaces
No full textAbstractWe establish a connection between certain classes of pseudodifferential operators and Hille–Tamarkin operators. As an application, we find the conditions that guarantee compactness and summability of the eigenvalues of pseudodifferential operators acting on the modulation spaces Mp,p
Automated detection of soma location and morphology in neuronal network cultures
No full textConfocal imaging data used for the development and validation of an algorithm for the automated detection of soma location and morphology in neuronal network cultures
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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