1,720,996 research outputs found
Factor analysis and principal component analysis
No full textWithin the vast archipelago of data-analysis tools, factor analy-sis and principal component analysis are among the islands more frequently visited by human scientists. Their success is due both to the century-old status they have reached, and to the fact that they are easy to apply nowadays, thanks, in particular, to the availability of dedicated data analysis software packages. Today even the most inexperienced student can avail of this user-friendly software, entrusting it with full responsibility for the numerous operations the techniques themselves require. This modus operandi produces results of scarce substantial interest and dubious scientific quality. This book is devoted to those who wish to exercise full intellectual control over the tools they employ, while acquiring the ability to critically appraise the results obtained in relation to the objectives of their research projects
Evidence-Based Medicine: una critica
No full textQuesto volume è il terzo numero unico di rivista a livello internazionale che si sia occupato di evidence-based medicine (EBM) nelle scienze umane, e il primo in assoluto sulle pagine del quale si confrontino sociologi, epistemologi e medici
Indagine sugli aggregati da C&D
No full textLa valutazione della capacità portante di sottofondi e fondazioni stradali si sta indirizzando dai test tradizionali come la prova di carico con piastra (PLT), verso i sistemi deflettometrici quali FWD e LWD, fino all’utilizzo dei sistemi di compattazione intelligente e di controllo in continuo della compattazione (CCC, CI).
L'approccio alla garanzia e controllo dei lavori nella costruzione delle pavimentazioni richiede che, metodi di misura anche diversi ma tra loro correlabili, possano essere impiegati sia dall'impresa, garante della bontà dei lavori, sia dalla DL o dal collaudatore che li controlla.
Oggi, molti dei moderni sistemi di compattazione vibrante a rullo, sono dotati di dispositivi di bordo atti a valutare il livello di rigidezza dello strato durante la compattazione, con passi di rilevamento dell'ordine dei dieci centimetri.
Allo stesso tempo, le apparecchiature FWD possono produrre un denso reticolo di misurazioni puntuali atte a valutare se la portanza del piano indagato sia, oltre che omogenea, anche conforme ai requisiti. Tali sistemi permettono di registrare rapidamente una grande mole di dati, garantendo un'indagine certamente dettagliata, ma che incrementa il processo di elaborazione ed interpretazione degli stessi da parte del tecnico.
Da queste premesse le Università di Bologna e di Pisa in collaborazione con Bomag, società leader nella produzione di macchine per la compattazione delle terre, e C.A.R. s.r.l., azienda imolese di riferimento nell’ambito del riciclaggio, hanno sviluppato una sperimentazione allo scopo di caratterizzare con prove ad alto rendimento i materiali di riciclo per sottofondi e fondazioni stradali. La ricerca ha come obiettivo ultimo l'utilizzo dei sistemi di compattazione CI-CCC e di prova FWD-LWD impiegandoli come metodi di validazione integrata. A tal fine è stato realizzato un sito sperimentale che ha visto l'utilizzo di rulli CI-CCC, differenti attrezzature deflettometriche e celle di pressione inserite nella pavimentazione
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
A preliminary comparison of Continuous Compaction Control and Portable FWD systems for Qc/Qa
No full textQc/Qa approach to pavement construction requires that correlated methods of measurement can be employed either by the contractors - guaranteeing the work reliability - and the controller. The case of bearing capacity evaluation for subgrade and foundation layers
is today moving from traditional testing (PLT), through Portable FWDs and FWDs, to the latest version of CCC and IC systems. Most of the modern vibrating compactors can be geared with in-built testing devices able to evaluate the stiffness level of the compacted layer
down to a decimetric span, during compaction. On the other hand, Portable FWDs can quickly define a dense pattern of measurements in order to assess if the surface stiffness complies with requirements. This paper presents a preliminary testing campaign, aiming to
contribute to the discussion of researchers for the CCC and PFWD systems integration as cross validation methods. A full scale double trial site have been constructed and monitored with a common IC-CCC drum and two different PFWDs. Results are also presented in the
form of spatial geostatistic analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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