1,721,113 research outputs found
Data model of completion of work for fiber-optic telecommunications networks
No full textIn the creation of new underground facilities
networks (e.g. public lighting, telecom networks, etc...), the
delivery of the technical documentation is just as important as
the delivery of the infrastructure itself. The availability of all the
information related to the work realized is a prerequisite for the
correct mapping of the infrastructure, its maintenance and
effective management of the service linked to it. For this purpose
it is essential to define a data model of the technical
documentation related to the completion of work (in the
following simply called data model of completion of work) that
constitutes a standard delivery for all suppliers. This model is not
only inclusive of all the necessary information, but it is also based
on an expressive and flexible format that facilitates loading it on
GIS platforms, being neutral and independent from the model of
the geographic database destination
Sperimentazioni in ambiente GIS circa l’impiego di tecniche interferometriche SAR da satellite per la generazione di DEM
No full textIn un’immagine SAR (Synthetic Aperture Radar, radar ad apertura sintetica) il digital number associato ad ogni pixel consiste in un numero complesso riferito al segnale retro diffuso dai bersagli colpiti: la parte reale corrisponde all'intensità, quella immaginaria alla fase.
Un interferogramma consiste in una mappa delle differenze di fase tra due scene SAR, dette master e slave. La fase interferometrica è dovuta sia alla diversa geometria di presa sia ad eventuali cambiamenti intercorsi tra le due acquisizioni.
Nelle successive fasi di elaborazione essenziali per la stima dei movimenti del suolo mediante la tecnica interferometrica differenziale SAR da satellite, uno degli elementi necessari per separare la componente di moto lungo la linea di vista satellite-bersaglio, dalle variazioni morfologiche del terreno, è la conoscenza preventiva di un modello digitale del terreno avente precisione sufficiente. La sottrazione all’interferogramma del DEM tradotto in termini di fase è detta spianamento; perché questa operazione sia efficace è necessario utilizzare un DEM che presenti un’accuratezza migliore dell’altezza d’ambiguità, cioè della lunghezza esistente lungo la direzione della linea di vista, corrispondente ad un ciclo di fase, per quella determinata coppia di immagini radar.
Una volta risolte le ambiguità di fase dell’interferogramma spianato e filtrato (operazione di unwrapping) è spesso necessario un ulteriore editing manuale, al fine di individuare quelle isole di fase nelle quali non sono state risolte correttamente le ambiguità a causa di variazioni di fase tra pixel adiacenti superiori a π. In questa delicata operazione devono essere stimate, inizialmente anche solo in modo approssimato, le correzioni da apportare.
Uno dei parametri fondamentali che caratterizza una coppia SAR è la normal baseline (figura 1) che ne definisce la sensibilità ai cambiamenti della scena tra un'acquisizione e l'altra. La nomal baseline è infatti il parametro che, insieme alla lunghezza d’onda, controlla l'entità del dislivello esistente lungo la linea di vista (los, line of sight) corrispondente ad un ciclo di fase (altezza d’ambiguità, height of ambiguity). E' allora possibile considerare anche un'altra coppia con baseline talmente corta da presentare un’altezza di ambiguità tanto alta da consentire uno spianamento efficace anche utilizzando un DEM di scarsa precisione Si può sottrarre poi il movimento desunto dalla coppia a baseline corta all'interferogramma della coppia a baseline lunga, tenendo presente che questo procedimento è corretto solo se si assume la linearità del movimento tra le due coppie e che queste presentino tra loro un angolo di vista tra le due orbite trascurabile. In caso contrario è necessario riproiettare il movimento desunto dalla baseline corta nella geometria dell'altra coppia. Il movimento del terreno misurato è da intendersi, infatti, nella direzione della congiungente sensore-bersaglio (los) e quindi se le due coppie presentano geometrie differenti, allora esse evidenziano due componenti del moto intercorso al suolo secondo linee di vista diverse.La sperimentazione condotta nell’ambito del presente lavoro ha toccato aspetti introduttivi connessi al valore della baseline spaziale e temporale al fine di ottenere una buona separazione degli effetti topografici dagli effetti di movimento, anche utilizzando un modello digitale a priori di scarsa precisione. In particolare sono state analizzate due aree di studio, la prima nella Terra Vittoria in Antartide, la seconda in Abruzzo, grazie al dataset reso disponibile da ESA per lo studio dei recenti eventi sismici
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
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
Three years of molecular monitoring of phytoplasma spreading in a plumgrowing area in Italy
No full textIn the plum growing area of Vignola (Northern Italy) a molecular monitoring was carried out in order to verify possibility to reduce the epidemic phytoplasma infection. Nucleic acids were extracted from plum leaf midribs for molecular tests to verify phytoplasma presence. Direct PCR using universal primer pairs P1/P7 followed by nested PCR with R16F2/R2 and specific primers R16(X)F1/R1 and RFLP analyses mainly with RsaI and SspI were employed to detect/identify phytoplasmas. The presence of phytoplasma specific DNA bands was observed after nested-PCR using either R16F2/R2 and R16(X)F1/R1 primers. From symptomatic and asymptomatic plum 16SrX-B phytoplasmas were identified. Four farms were monitored during 2000 testing 11 Japanese plum varieties: in June among 40 samples, all from symptomatic plants about 23% were positive in the first nested PCR reaction and 92% in the second one performed with group specific primers 16Sr(X)F1/R1. When the same plants were retested in October, 39 out of the 40 samples were positive in direct PCR. During July 2001 in two of the above farms a total of 57 asymptomatic plums were tested: in the first farm 21% of the plants tested were positive and in the second 17%. In July 2002 both symptomatic and asymptomatic plum were monitored in 3 different fields. Ten out of 20 samples from symptomatic plum resulted to be infected by 16SrX-B phytoplasmas, 5 were negative and in the other samples phytoplasmas belonging to groups 16SrXII-A, 16SrI-B and 16rIII-B were identified. Asymptomatic plant that were re-grafted in 2001 on rootstock where symptomatic scions were previous observed showed that 67% of the plant tested were infected by 16SrX-B phytoplasmas showing a clear evidence that the rootstock was colonized by the pathogens that are able to infect the new grafted scions just during one winter season
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