1,721,011 research outputs found
Vector-raster server-side analysis: a PostGIS benchmark
No full textReport generation from coverages around points of interest (POIs) or in areas of interest (AOIs) is a common need in thematic research projects. The extracted information adds value to the POIs or AOIs dataset by enriching its information content. In a common scenario, POIs or AOIs are usually vector data whereas background thematic datasets are often raster data. The paper investigates different approaches for zonal statistic computation about both raster and vector data with particular focus on server-side free and open source software (FOSS)-based solutions. Extensive performance tests are based on PostGIS (the spatial extension of popular PostgreSQL (http://www.postgresql.org/) FOSS DBMS) 2.0. This version is the first to offer raster support. Previously, vector-raster analysis was not supported by any FOSS DBMS environment and such analyses were possible in a FOSS server-side environment using geographical information system( GIS) tools (e.g., Geographic Resources Analysis Support System (GRASS) GIS) and Open Geospatial Consortium (OGC) Web Processing Server. PostGIS performance data from the tests are compared to an almost standard ESRI ArcGIS desktop approach. A project aimed at monitoring fire alerts in African protected areas provides the benchmarking application. The computation of people living in the surroundings of POIs (alert points from Global Fire Information Management System) based on a world population density dataset (LandScan) is the benchmarking query. The impact of many parameters on performances is considered: the adopted tile size in the storing of the raster in the DBMS, the dimension of queried areas in relation to the abovementioned tile size, the number of queried features
GIS and WEB-GIS, commercial and Open Source platforms general rules for Cultural Heriage Documentation
No full textAn Open Source system for P.I.C.A.: a project for diffusion and valorization of cultural heritage
No full text
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
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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