1,721,051 research outputs found
Self-attraction effect and correction on three absolute gravimeters
No full textThe perturbations of the gravitational field due to the mass distribution of an absolute gravimeter have been studied. The so called Self Attraction Effect (SAE) is crucial for the measurement accuracy, especially for the International Comparisons, and for the uncertainty budget evaluation. Three instruments have been analysed: MPG-2, FG5-238 and IMPG-02. The SAE has been calculated using a numerical method based on FEM simulation. The observed effect has been treated as an additional vertical gravity gradient. The correction (SAC) to be applied to the computed g value has been associated with the specific height level, where the measurement result is typically reported. The magnitude of the obtained corrections is of order 1E-8 m/s2
Confronto EURAMET.AUV.V.K2 in bassa frequenza
No full textNel rapporto sono riportati i risultati di misura delle misurazioni effettuate, in ambito di un confronto EURAMET, su un trasduttore di accelerazione a bassa frequenza. I risultati serveno a supportare e validare le incertezze dichiarate nelle corrispondenti CMC.In the report, the results of the mesaurements carried out, in the framework of a EURAMET comparison, on an low-frequency acceration transducer are reported. The results are necessary to support and to validate the uncertainty declared in the related CMCs
Absolute Measurements of the Free-Fall Acceleration g in Vesuvio, Campi Flegrei and Ischia
No full textIl lavoro descritto in seguito è stato svolto nel mese di agosto 2010 dall’Istituto Nazionale di Ricerca Metrologica (INRIM) di Torino nell’attività di cooperazione con l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) – Sezione di Napoli “Osservatorio Vesuviano”.
Si riportano i risultati sperimentali delle misure assolute dell’accelerazione di caduta libera g eseguite in Vesuvio, Campi Flegrei e Ischia. Le misure sono state effettuate con il gravimetro assoluto trasportabile IMGC-02.The work hereafter described was carried out on August 2010 by the Istituto Nazionale di Ricerca Metrologica (INRIM) of Turin (Italy) in the framework of a cooperation with the Istituto Nazionale di Geofisica e Vulcanologia (INGV) – Sezione di Napoli “Osservatorio Vesuviano”.
The experimental results of absolute measurements of the free-fall acceleration g carried out in Vesuvio, Campi Flegrei and Ischia are reported. Gravity measurements were performed with the transportable absolute gravimeter IMGC 02
Sensitivity of the Drop Length in a Rise and Fall Absolute Gravimeter: Simulation and Data from the IMGC-02 Instrument Operating in Different Measurement Sites
Full text linkIn ballistic absolute gravimeters, the length of the analyzed trajectory of the falling object plays a crucial role in the accuracy and the precision of the determination of the gravity value. The effect is generated by different known and unknown sources. They depend both on the instrument setup, e.g. mechanical systems or fringe signal processing, and the measurement site, namely the stiffness of the floor. The dominant aspect concerns the recoil which appears at the start of the drop. In the case of rise and fall method, as for the IMGC-02 apparatus, the magnitude of such recoil is higher with a respect to the freefall one. A detailed analysis of the sensitivity of the drop length for this absolute gravimeter was never done before.
The goal of the study is to evaluate how the variation of drop length can affect the measurement of the free fall acceleration, in order to achieve best solution to minimize the perturbation without reduce the resolution. The solution must be found as a function of the different measurement site and its associated uncertainty were evaluated
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
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