1,720,970 research outputs found
Passive and active Sonar applications for a nonuniform and low cost Linear Array
No full textone of the reasons to use a non-uniform linear array (NULA) is to reduce the cost and complexity of the array, since it can have fewer sensors than an ULA system.
In this paper, authors describe the construction of a low-cost, ten-hydrophones, nonuniform linear array to be employed in passive and active sonar applications.
Many experiments were conducted, under controlled conditions (large pool), oriented to
characterize both individual transducers as well as the complete array. Using the array in “passive” mode, employing an omnidirectional sound source and a non-impulsive signal,
beamforming and inverse filtering techniques, the authors evaluated array directivity over a wide range of frequencies (1-23 kHz) and also its capability to estimate the direction of
arrival (DOA).
Furthermore, this work also focuses on searching objects and identification. Different test were performed, in order to estimate system performances when used as the receiver of an
active sonar. Using sine-sweep signals, and a specific real-time software developed by the authors, several measures were conducted in the shallow and very shallow water showing
the ability of the system to detect objects in a 45° wide angle
A Digitally Controlled Two Dimensional Loudspeaker Array
No full textA “sonic chandelier” has been designed and manufactured to be installed in the new “Casa del Suono” in Parma. This
museum will be an exhibition of sound reproduction devices from the 20th century, and a multi-channel audio
laboratory as well. The chandelier is a 64-channel, dome shaped array of 228 speakers suspended in the center of the
main hall of the museum, at a height of 4 meters. It creates, by means of Wave Field Synthesis, virtual sources moving
above the listener’s heads, and will reproduce an original spatial music composition. This listening experience plays the
role of a very advanced music reproduction system, in contrast to the other, historic devices exhibited. An important
requirement is that the sound produced must be confined to a restricted area beneath the system itself, in order not to
interfere with other exhibits present in the hall. The physical structure and algorithm design are described, as well as
some listening tests, performed for now on a reduced linear version of the array itself
Listening Tests of the Localization Performance of Stereodipole and Ambisonic Systems
Full text linkIn order to find a possible correlation of objective parameters and subjective descriptors of the acoustic of theatres,
auditoria or music hall, and so to perform meaningful listening tests, we need to find a reliable 3D audio system
which should give the correct perception of the distances, a good localization all around the listener and a natural
sense of realism. For this purpose a Stereo Dipole system and an Ambisonic system were installed in a listening
room at La Casa Della Musica (Parma, Italy). Listening tests were carried out for evaluating the localization
performances of the two systems
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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