1,720,961 research outputs found
Integration of Ground Penetrating Radar with Global Position System and Inertial Measurement Unit for archaeological application
No full textIn the last years, Ground Penetrating Radar (GPR) technology has been used extensively in different fields of heritage investigation. The use of other technics that integrate GPR technology as Global Positioning System (GPS) together with Inertial Measurement Unit (IMU) can effectively improve the precision of buried object location, by means of an efficient control of route and attitude of the GPR. This article aims at investigate on some technics oriented to the issues solution, as those that are consequence of used specific detection methods, e.g. GPR pulled by a terrestrial vehicle or carried by an aerial platform. Moreover, we present a basic structure of our low cost design, which integrates functionalities of GPS and IMU dedicated to GPR’s use
System for positioning and tracking of GPR based on inertial and GPS data integration
No full textAll applications that use GPR in remote mode need to combine to the radar an accurate positioning system. Such system allows to solve errors in the localisation of buried objects, which are generated by the measurement conditions, i.e.: by the slope of soil, in the case of a ground-coupled radar, and by the airplane attitude, in the case of a GPR mounted on aerial vehicle. This paper presents the implementation of a low-cost system for determining positioning, tracking and trim data of GPR. This system integrates data of a Global Positioning System (GPS) with those of an Inertial Measurement Unit (IMU)
30–512 MHz power amplifier design using GaN transistor
No full textIn this article a class AB single-ended power amplifier with 30-512 MHz frequency band and 100 W saturated output power has been designed and implemented using a GaN transistor. The measured compressed gain is 19 ± 1 dB, the average PAE is 61% and the return loss is always better than −7.5 dB
AlphaSat Ka-band and Q-band receiving station in Rome. Development, status and measurements
No full textA Ka-band (20 GHz) and Q-band (40 GHz) receiving station, located in Rome (Italy), has been designed and implemented to receive the beacon of the AlphaSat satellite Technology Demonstrator Payload 5 'Aldo Paraboni'. Ka-band station is complete and its preliminary measurements are shown. Mechanical antenna tracking is also foreseen. Q-band station is being assembled and should be tested in early 2015. A laboratory characterization of all blocks and subsystems has been carried out and is briefly described. The design and implementation of a W-band microwave radiometer is also on going, whereas Ka- and Q-band beacon data are combined with measurements from a meteorological station, raingauge and disdrometer
GPR/GPS/IMU system as buried objects locator
No full textIn the last years, Ground Penetrating Radar (GPR) technology has been extensively used in several different fields, including archaeology and cultural-heritage diagnostics. The integration of GPR with other positioning devices, such as a Global Positioning System (GPS) and an Inertial Measurement Unit (IMU), can significantly improve the accuracy of buried-object location, by means of an efficient control of GPR route and attitude. This article aims at investigating solutions for an accurate location of buried objects when a GPR is pulled by a terrestrial vehicle or carried by an aerial platform. In particular, a low-cost system is presented, which integrates functionalities of GPS and IMU specifically dedicated to GPR use. The device has been designed, realized and finally its performance was tested in the laboratory
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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