1,721,002 research outputs found
Dynamic error correction of a thermometer for atmospheric measurements
No full textThis work deals with the dynamic correction of a thermometer for atmospheric measurements. The sensor analysed is the one launched onboard the Huygens probe of the Cassini mission. The specific aspects of the measurement are related to the strong changes in the fluid-dynamic conditions during the operative phase. This peculiarity does not allow the use of one of the various correction techniques based on the knowledge of the dynamic characteristics of the sensor. The thermometer, however, has the peculiarity of being composed of two independent platinum sensors, having very different dynamic
properties. The study, starting from a previously conceived dynamic scheme of the sensor, assesses the possibility of
determining continuously, from measurement data, the current values of the four time constants required for dynamic characterisation. Lastly one procedure for the dynamic correction of the measurements is presented, along with some
verification of its effectiveness and, of the impact on the overall measurement uncertainty
Messa a punto di un sistema di termovuoto per la verifica del controllo termico di strumentazione operante nello spazio
No full text
Misure di emissività di materiali per uso spaziale mediante un pirometro ottico
No full textPer la misura di emissività, si propone un metodo veloce ed economico, basato sui dati acquisiti da un pirometro ottico. Viene eseguita una misura di emissività in direzione normale alle superfici di alcuni materiali ad uso spaziale. I dati sperimentali, vengono confrontati con quelli ottenuti dal modello teorico e quelli disponibili in bibliografia. Il metodo, permette di effettuare, misure di emissività con un’incertezza fino a 1,5% del valore letto, nel caso di superfici con emissività superiore a 0,90; in ogni caso, l’incertezza non supera il 3,6% con superfici a emissività compresa tra 0,30 e 0,90. Nel caso dei materiali studiati, l’incertezza di misura ottenuta, risulta essere minore di quella dichiarata dai produttori
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
Atmospheric effects on rotary LiDAR-based systems for UAS missions
No full textUrban Air Mobility (UAM) and Advanced Air Mobility (AAM) are new air transportation concepts in urban areas, both based on Unmanned Aircraft Systems (UAS). The last decade has witnessed a constant growth of UAS missions in urban areas, for various military operations, civil and scientific tasks. During UAS missions, identification and tracking of the surrounding environment is fundamental (e.g., obstacles or other
vehicles, stationary or moving). It is therefore crucial to test atmospheric effects like temperature, pressure, and humidity variation on the on-board or ground sensors. This paper investigates the effects of temperature and relative humidity variation on rotary LiDAR (Light Detection and Ranging)-based distance measurements, to characterize its functionality by simulating several weather conditions. The objective this work is
characterizing the sensor and validating a mathematical model of distance measurements in the presence of temperature and humidity variations. The rotary LiDAR is part of a ground control station system prototype for UAS operations, recently developed
by the authors, to date tested and validated only in indoor scenarios. The core of the system is a real-time mechanically rotating LiDAR sensor (RPLIDAR Model A1M8), linked to a Raspberry Pi 3 board for data management and interfaced to a PC-based ground station
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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