1,721,003 research outputs found
Tecniche di classificazione e monitoraggio delle aree agricole nei paesi dell’Africa Centro-Orientale da immagini satellitari
Full text linkIl progetto Africover per l’Africa Orientale fu attivo fra gli anni 1995 e 2002, ed ebbe come obiettivo la produzione di un archivio digitale georeferenziato volto alla classificazione delle tipologie di copertura del suolo, nonché alla determinazione della loro destinazione di utilizzo; venne inoltre introdotto un riferimento geodetico omogeneo e stabilita una chiara ed univoca toponimia di strade e bacini idrici presenti nell’area. La FAO e la Cooperazione Italiana supportarono, in risposta a numerose richieste di assistenza a livello sia nazionale che locale, la creazione dell’archivio e la realizzazione delle mappe tematiche di land cover poste a fondazione dei criteri decisionali per la gestione e lo sfruttamento delle risorse naturali delle regioni africane. A partire dal 2002 l’archivio realizzato non è mai più stato aggiornato; da questo punto parte il nostro lavoro, con l’obiettivo di realizzare mappe aggiornate delle aree agricole del Kenya impiegando sensori della classe del Thematic Mapper, sviluppare una metodologia di stima dello stato delle culture per un accurata previsione dei raccolti, sviluppare ed implementare un sistema software che renda agevole la creazione di mappe di uso del suolo da immagini satellitari.
Il progetto SBAM (Satellite Based Agricultural Monitoring), risponde alle esigenze di ottenere delle mappe aggiornante ed accurate delle aree dedicate all'agricoltura nei paesi dell'Africa Centrale, fornire alle istituzioni di ricerca locali il know how per perseguire l’attività di aggiornamento del land cover ed attivare un sistema di monitoraggio dello stato di salute delle colture e previsione dei raccolti ed infine potenziare la stazione di telerilevamento del BSC (Broglio Space Center) di Malindi.
La procedura di classificazione MDT (Multi-variate Decision Tree) del dato satellitare segue un approccio fenologico multi-temporale, supportato dall’impiego della zonazione agro-ecologica; un sistema automatico di modellizzazione climatico-ambientale interviene a calibrare i parametri di simulazione in ambiente FAO AquaCrop per l’individuazione dei parametri di stress attivi sulle coltivazioni e l’effetto da essi determinato sul livello di produzione atteso.
L'area di studio comprende i paesi dell'Africa Centrale ed in particolare i paesi che cadono nel cerchio di acquisizione della stazione di telerilevamento del BSC di Malindi.We investigated the use of phenological information extracted from satellite imagery combined with crop calendar and supported by agro-ecological zoning (AEZ) in accurate crop classification and monitoring. Vegetation indices extracted from Landsat 8 imagery are capable to track the vegetation development through the year and from them the phenological profile can be extrapolated and implemented into a multi-temporal automatic classification process to detect agricultural vegetated areas and to discriminate among different crop species.The classification procedure is supported by the agro-ecological zoning which, based on crop modeling and environmental matching procedures, identifies crop-specific environmental limitations under assumed levels of inputs and management conditions. The Fao AquaCrop simulation model was implemented to estimate the site specific crop yield response to different stress factors. Accurate crop classification and monitoring is the main objective of the SBAM (Satellite Based Agricultural Monitoring) project funded by the Italian Space Agency and focused on Kenya
A scalable fire danger index based on sentinel imagery
Full text linkThe incidence of wildfires and megafires and their disastrous consequences is increasing all over the planet. According to the latest European Forest Fire Information System annual fire report, in 2021 alone wildfires burned a surface area more than twice the size of Luxembourg, including more than a thousand square kilometres of Natura 2000 protected areas. In addition, 2022 has registered the highest number of wildfires since 2006, and will also be recorded as one of the driest years on record. Assuming that the most efficient and cost-effective way limit the damage caused by wildfires consists in their prevention, building tools to allow the decision makers to allocate resources using state of the art technology and fresh data is of the utmost importance. To this end, the combined usage of data from weather and satellite platforms capable to provide data on a regional or national scale and at a high temporal frequency provides the optimal solution for assessing and monitoring the state of the vegetation. However, users of fire danger product users often complain about the resolution of the provided products. While moderate- or coarse-resolution products may be adequate to cover the regional or national scale, high-resolution products are required to properly describe the fire danger in relatively small-sized areas of high interest in fire danger modelling, such as wildland-urban interfaces, national parks or protected areas. Using a different fire danger product based on the spatial scale of the target may be impractical and increase the workload and training requirements for the personnel. For this reason, we propose a scalable fire danger index based on Sentinel imagery that is able to cover different spatial scales by exploiting the surface reflectances provided by different Sentinel products (i.e. Sentinel-2 and Sentinel-3).
This novel index, named Daily Fire Danger Index, exploits both weather and satellite data to estimate all the main variables of fire danger, such as the amount of dead fuel, moisture of the dead and live fuels, wind speed, evapotranspiration etc, and is calibrated using the historical records of wildfire occurrence in the target region. In particular, the live fuel moisture content is estimated using a state of the art procedure based on the inversion of radiative transfer models of the PROSAIL family. The index was tested in Sardinia, a region well-known for its proneness to wildfires and which is also regularly affected by megafires, and the performance comparison with the Canadian Fire Weather Index shows very significant improvements on the capability to discriminate fire danger even at a moderate resolution. Finally, the 2021 Planargia-Montiferru megafire was selected as a case study to showcase the added value of the high-resolution version of the index
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
Non Parametric Statistical Tests for the Analysis of Multiple-sensor Time Series of Remotely Sensed Data
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
