1,721,031 research outputs found
Vibrations of Superyacht Structures: Comfort Rules and Predictive Calculations
No full textThe dynamic behaviour of hull structures has a great impact on the comfort level on board modern superyachts and, from the structural point of view, this is one of the subjects shipyards are more interested in. In addition many important Classification Societies have issued new rules and regulations for the evaluation of vibration maximum levels. Such rules, usually named as "Comfort Class Rules", contain both the general criteria for noise and vibration measurement in various yacht areas, and maximum limit values which such measurements should fall into. Despite the effort of Classification Societies to keep a certain harmonization of criteria and of limit values, the existing diversities often create serious uncertainties to designers. In this work a case study is presented, consisting in a 60 meters superyacht, on which a detailed FEM investigation has been carried out in order to investigate the dynamic behaviour of hull and superstructures. The results of modal and transient analyses are compared with a first series of experimental data gathered during the vessel construction. At the moment sea trial are under course and the vibration measurements are going to be carried out in several part of the vessel
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
Risposta dinamica strutturale di superyacht: aspetti normativi e verifiche preliminari
No full textIl livello di comfort a bordo dei moderni superyacht è stato recentemente oggetto di attenzione da parte delle più importanti Società di Classifica che hanno emanato nuove direttive per la valutazione delle vibrazioni e del rumore. Tali direttive, indicate genericamente come "Comfort Class Rules" contengono sia i criteri per la misura delle vibrazioni e del rumore in diverse zone dello scafo, sia i valori massimi entro i quali tali misure devono rientrare affinchè all'unità possa venire assegnata la "Comfort Class". Per quanto riguarda più specificamente le vibrazioni, oggetto del presente studio, tutte le normative sono ispirate alle già esistenti regolamentazioni ISO del 1984, sostituite recentemente dalle norme ISO 2000. Nonostante lo sforzo da parte delle Società di Classifica di mantenere una certa omogeneità nei criteri e nei valori massimi ammessi, molte normative presentano ancora differenze che possono mettere in difficoltà gli operatori.
In questo lavoro viene presentata una sintesi delle principali regolamentazioni attualmente esistenti in merito alla Comfort Class per unità da diporto. Vengono poi descritte le fasi principali di una indagine numerica condotta su un superyacht di 55 metri di lunghezza avente lo scopo di studiare il comportamento dinamico della parte poppiera dello scafo in acciaio e delle sovrastrutture in alluminio per evidenziarne eventuali criticità e confrontare i risultati con i limiti proposti dalle normative. L'indagine prevede anche una conferma sperimentale che sarà condotta prossimamente in cantiere
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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