1,721,012 research outputs found
Automatic Procedure for Monitoring Urban Land Cover Changes by Multitemporal ASAR Images
No full textIn this paper an automatic procedure for change detection from multitemporal advanced synthetic aperture radar (ASAR) images is presented. The model is structured in four main blocks: a set of standard preprocessing procedures, a feature-extraction module, a neural-network classifier and a change detection module. To improve the capabilities of the neural network, the feature-extraction module derives a
set of features from a series of multitemporal ASAR images, such as mean and standard deviation of four backscattering intensity images (one per each season of the year) and their textural features (Energy and Contrast) based on the Gray Level Co-Occurrence Matrix (GLCM) method [2,3]. The supervised neural network algorithms [4,5] is used to classify urban areas versus not urban areas. It is based on the multilayer perceptron MLP approach and trained with the error back-propagation (EBP) learning algorithm. Finally, the change detection map is obtained by comparing two classified images taken at two different times. To validate the model, test images acquired by the ENVISAT ASAR over Rome, Italy and its surroundings are used. Changes occurred from 2005 to 2009 are automatically recognized with an accuracy of about 75%, while the classification accuracy obtained over the urban areas is higher than 90%. The developed algorithm is capable of efficiently identifying urban growth on big scale areas with short processing time
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
Relating mean radio sounding profiles to surface fluxes for the very stable boundary layer
No full textA dataset collected during a measurement campaign in the middle of the Po Valley, Italy, is used to investigate the boundary-layer structure in stable conditions. Empirical formulations for temperature and wind profiles derived from Monin-Obukhov similarity theory are used as regression curves to fit radiosounding profiles in the lower half of the boundary-layer. The best fitting parameters of the regression are then compared to the surface turbulent fluxes as measured by a co-located sonic anemometer. This comparison shows significant discrepancies and supports earlier results showing that surface fluxes, in the limit of high stability, are not adequate scalings for mean profiles. The most evident differences are found for cases for which the bulk Richardson number turns out to be quite large. One of the practical consequences is that boundary-layer height diagnostic formulations that mainly rely on surface fluxes are in disagreement with those obtained by inspecting the thermodynamic profiles recorded during the radiosounding ascent. Moreover the incorrect scaling of similarity profiles in stable conditions leads to the erroneous diagnosis of 2-m air temperatures used in numerical weather prediction validatio
The economic impact of caregiver for patients with atrial fibrillation: an italian survey
No full textVariations 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
Early postnatal Genotype-Environment interactions: Effects on rat brain growth and adult behaviour
No full textLa dimensione economica del caregiving formale e informale nel paziente con Fibrillazione Atriale
No full textAppropriate 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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