1,720,976 research outputs found
Automatic 3D foetal face model extraction from ultrasonography through histogram processing
Full text linkUltrasound is by far the most adopted method for safe screening and diagnosis in the prenatal phase, thanks to its non-harmful nature with respect to radiation-based imaging techniques. The main drawback of ultrasound imaging is its sensitivity to scattering noise, which makes automatic tissues segmentation a tricky task, limiting the possible range of applications. An algorithm for automatically extracting the facial surface is presented here. The method provides a comprehensive segmentation process and does not require any human intervention or training procedures, leading from the output of the scanner directly to the 3D mesh describing the face. The proposed segmentation technique is based on a two-step statistical process that relies on both volumetric histogram processing and 2D segmentation. The completely unattended nature of such a procedure makes it possible to rapidly populate a large database of 3D point clouds describing healthy and unhealthy faces, enhancing the diagnosis of rare syndromes through statistical analyses
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
On the thermo-mechanical behavior of NiTi shape memory elements for potential smart micro-actuation applications
Full text linkAmong smart and functional materials, the shape memory alloys are enabling the development of a new class of devices for the automotive, aerospace, biomedical, and mechanical applications based on the shape memory and superelastic effects. In this work, a study on the mechanical response of NiTi shape memory micro-elements, in the so-called “snake-like” configuration, is reported. These elements were patterned by means of laser micro-processing from thin NiTi sheets and then chemically etched. Different micro-elements, as function of the number of the curvatures replicated, were fabricated and tested. The functional performances of the micro-elements were characterized through calorimetric analysis for the definition of the operating temperatures and through thermo-mechanical testing for the evaluation of their actuating response. Mechanical tests were carried out to assess the tensile behavior of martensite and austenite phases separately, and for evaluating the thermal hysteresis under different constant loads during cooling/heating loops. Moreover, finite element modeling was also accomplished to analyze the stress distribution in both the martensitic and austenitic phases as loading
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
Landmarking-based unsupervised clustering of human faces manifesting labio-schisis dysmorphisms
Full text linkUltrasound scans, Computed Axial Tomography, Magnetic Resonance Imaging are only
few examples of medical imaging tools boosting physicians in diagnosing a wide range
of pathologies. Anyway, no standard methodology has been dened yet to extensively
exploit them and current diagnoses procedures are still carried out mainly relying on
physician's experience. Although the human contribution is always fundamental, it is
self-evident that an automatic procedure for image analysis would allow a more rapid
and eective identication of dysmorphisms. Moving toward this purpose, in this work
we address the problem of feature extraction devoted to the detection of specic dis-
eases involving facial dysmorphisms. In particular, a bounded Depth Minimum Steiner
Trees (D-MST) clustering algorithm is presented for discriminating groups of individu-
als relying on the manifestation/absence of the labio-schisis pathology, commonly called
cleft lip. The analysis of three-dimensional facial surfaces via Dierential Geometry is
adopted to extract landmarks. The extracted geometrical information is furthermore
elaborated to feed the unsupervised clustering algorithm and produce the classication.
The clustering returns the probability of being aected by the pathology, allowing physi-
cians to focus their attention on risky individuals for further analysis
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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