1,720,972 research outputs found
Experimental validation of equalizing filter for car cockpits designed with Warping technique
No full textImplementation of Real-time Partitioned Convolution on a DSP Board, 2003
No full textConvolution using very long filters is required in order to achieve realistic artificial reverberation or spatial effects. Unfortunately, DSP (Digital Signal Processors) platforms have limited computational power (compared with a modern PC) and consequently it is not possible to design very long filters based on typical time-domain, direct-form algorithms, i.e. FIR or IIR structures. To perform this task, other algorithms are necessary. In this paper the implementation of a real-time partitioned convolution algorithm on a DSP platform will be demonstrated. In this manner, efficient convolution with long Impulse Responses is attained, with the advantage of low input/output delay. 1
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
NOT-IMPULSIVE TECHNIQUES FOR SONAR IMAGING
No full textAbstract: Techniques based on impulsive sources are used since the beginning of the Underwater Acoustic science, to evaluate the distance of objects and to plot the profile of the sea bottom. In this paper the authors investigate the behavior of three not-impulsive techniques for the measurement of impulse responses: MLS (Maximum Length Sequence) signal, linear sine sweep and logarithmic sine sweep. This work will focus the attention on advantages and defects of these tree different methods, in comparison with the traditional pulse-based sonar techniques. The mathematical theory for the generation of the MLS, sine sweep signals and for the deconvolution of the system’s impulse response are first described. Then a software implementation of the measurement methods, based on the creation of plug-ins for a shareware waveform editor, running on a low cost PC is demonstrated. Some experiments conducted under controlled conditions and in the sea show that the proposed techniques produce images of the bottom profile with higher signal-to-noise ratio and better spatial resolution than those obtainable with the impulsive technique. Moreover signal-to-noise ratio increases using sine sweep signal instead of MLS one. The new techniques seem superior also for some practical aspects connected with their very nature, which make them almost inaudible and makes the sound source barely localizable: this is very important for military applications
Car cockpit equalization by warping filters
No full textSound reproduction within a car is a difficult task. Reverberation, reflection, echo, noise and vibration are some of the issues to account for. A first step in the direction of increasing sound comfort is that of equalizing the acoustic pressure response in the frequency domain. In this paper an automatic toolto develop warping inverse filters for target car cockpits was designed and validated through experiments in commercial cars
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