1,720,975 research outputs found
Microphone array measurements for the identification of mobile noise sources
No full textA modern parameter in the global quality assessment of high speed trains is the noise emission. An
innovative method for the identification and comparison of mobile acoustic sources was implemented: the
microphone array. Basis of the method is the “beamforming algorithm” that from a measure of the
acoustic pressure in several points allows to investigate the position and the characteristics of the sound
source. This source can be either fixed or moving respect to the array making the method capable of
separating different sources among a general noise signal perceived during a vehicle pass-by.
The method was developed using numerical models and proved to be effective testing it on site with
different known sound sources both fixed and moving.
After these tests an application of the pass-by noise measurements generated by a rail convoy was
investigated. The occasion was given by an experimental campaign settled for the evaluation of noise and
vibration emission of a standard ballast superstructure, within an European research
program(“HIPERTRACK”). Results showed the capability of the method to distinguish multiple sound
sources. The method showed the possibility to identify the noise emitted by a single wheelset. In this
paper an analysis of the noise emitted by the wheel-track interaction of different convoy typologies on the
same ballast superstructure has been performed and results will be discussed. A comparison between
noise and vibration recorded on the rail showed a good agreement. Time/frequency analysis was finally
implemented to identify the spectrum of the emission associated with every single bogie
Dispositivo per prove di rendimento e fatica su viti a ricircolo di sfere
No full textIl dispositivo progettato permette di realizzare prove a fatica sulle trasmissioni meccaniche a viti a ricircolo di sfere e di valutare contestualmente il rendimento meccanico della trasmissione e lo stato di usura della stessa.
Tale dispositivo sfrutta il ricircolo di potenza, ottenuto precaricando, attraverso delle molle a tazza, due chiocciole montate su un unica vite. Tale accorgimento permette di ridurre la potenza meccanica che deve essere introdotta nel dispositivo per realizzare le prove a fatica e nello stesso tempo riduce i carichi che si scaricano sui supporti della vite.
Un opportuno sistema di misura acquisisce il valore della forza di precarico esercitata dalle molle a tazza, le forze scaricate a terra (reazioni vincolari) e la distanza fra le due chiocciole. Attraverso questi dati è possibile valutare il rendimento della trasmissione e il suo stato di usura
Force measurement during gait therapy assisted by a robotic treadmill - The case of Lokomat®
No full textThe present paper deals with force measurement during gait therapy assisted by a special robotic treadmill with driven robotic orthoses that guide inferior limbs movements. The objectives, the measurement setup and the results are presented. This work has been carried out in order to gather data necessary to begin the analysis and the design of a new ankle motion device. The presented results also show how these measurements can be useful in gait parameters assessment and patient's muscle activity level
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
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