1,720,993 research outputs found
GIS Based Analysis and Accuracy Estimation of Sea Surface Temperature from MODIS Thermal Images
No full textCapturing the thermal emission from the Earth, satellite sensors permit to derive sea surface temperature (SST). The infrared radiance intercepted by the sensor also depends on other variables, such as the surface emissivity, viewing geometry and the atmospheric contribution. All variables that affect atmospheric absorption and emission must be carefully considered. The brightness temperature of the surface measured by satellite sensor needs transformation to obtain SST. To remove the noise generated by the atmosphere, an equation can be used to derive a set of SST algorithm coefficients that can be applied to the brightness temperature image. Temperature data from specific points are necessary for the scope. This article aims to demonstrate that, in absence of an adequate temperature dataset, SST can be derived by MODIS thermal images (pixel dimensions: 1 km x 1 km) using Copernicus data even if it has a lower spatial resolution (0.0625° x 0.0625°). The study area includes an extended part of the Mediterranean Sea which contains the Strait of Sicily, the Adriatic, Ionian, and Tyrrhenian Seas. The Pathfinder algorithm developed by NOAA based on an equation with pre-established coefficients is also applied for comparison. Temperatures recorded by buoys are used to test the result accuracy. The experiments testify the good performance of the adopted approach
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
GIS analysis for defining sea level rise effects on Sicily coasts for the end of the 21stcentury
No full textCoastal regions around the world are experiencing the increasing threat of sea level rise (SLR) due to climate change. Predictive models are needed to identify areas at risk of flooding and plan future activities aimed at avoiding, or at least limiting, damage to the natural environment, buildings, and people. Geographic Information Systems (GISs), through the processing of georeferenced data, allow not only to map the coastal areas that may be submerged, but also to carry out calculations and analysis to support further studies and insights. This paper examines the impact of SLR on the coasts of Sicily, Italy, using a Digital Elevation Model (DEM) of the study area (resolution: 20 m x 20 m) and GIS tools. The objective is to provide medium scale maps of the potential submerged zones for the end of the 21st century (2071-2100) as resulting from SLR values supplied by the Copernicus platform and identified as the IPCC (CMIP5) RCP4.5 scenario. The bathtub method available in literature is carried out using Quantum GIS (QGIS) software version 3.28. Attention is also focused on the limits and advantages of the adopted approach. The experiments demonstrate on the one hand the versatility of the GIS tools that allow the implementation of the bathtub method, on the other the seriousness of the SLR, given the considerable extension of the areas at risk of submersion as resulting from the maps produced for Sicily coasts
Integrating elevation and bathymetric data in GIS for a continuous 3D model of Ischia Island and surrounding seabed
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
A reaction diffusion model with a stochastic boundary condition
No full textIn the framework of the dynamical evolution of the chemical reactions of the sulphur dioxide with the surface of calcium carbonate stones in the process of the degradation of the cultural heritage, starting from a well known deterministic mathematical model, in order to better describe the high variability of the external sulphur dioxide concentration we introduce a suitable stochastic dynamical boundary condition. As boundary condition we take a Jacobi process, solution to a Brownian motion driven stochastic differential equation. We discuss both the mathematical problems arising from considering a lower regular boundary condition and in particular the global existence and (pathwise) uniqueness of the reaction diffusion system coupled with this stochastic boundary condition. The proof relies on a splitting strategy, which allows to deal with the low regularity of the boundary condition. A discretization scheme based on the same splitting is proposed and some numerical samples are shown
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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