996 resultados para Sound propagation
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We numerically study nonreciprocal regimes of surface plasmon-polariton at the interface between two gyrotropic media. We predict existence of isolated unidirectional TE and TM surface modes guided by the interface between gyroelectric and gyromagnetic media.
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premiered by Mel Puga Iglesias
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Connections can be suggested between music’s occupation of physical space, its relative ‘presence’ (using Edward Hall’s notion of proxemics), and the various senses of movement which pervade it. Movement might be seen to operate with respect to music at a variety of levels of metaphorisation – as increasingly complex chains of analogy which point back to our early physical experience of the world. But of course music is, fundamentally, action. Humans put energy into systems - external or internal to themselves - which transduce that energy into the movement of air. At the acoustic level music is, emphatically and unmetaphorically, movement. Perhaps such simple physical perceptions form one route through which we might understand and explore shared senses of meaning and their capacity for ‘transduction’ between multiple individuals. Our (developmentally) early sensory models of the world, built from encounters with its physical resistances and affordances, might be a route to understanding our more clearly encultured and abstracted ('higher' level) understandings of music.
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This article will introduce a specially-commissioned edition of the JSS centering on articles developed from the International Symposium May 2014 by the Recomposing the City project.
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To intercept a moving object, one needs to be in the right place at the right time. In order to do this, it is necessary to pick up and use perceptual information that specifies the time to arrival of an object at an interception point. In the present study, we examined the ability to intercept a laterally moving virtual sound object by controlling the displacement of a sliding handle and tested whether and how the interaural time difference (ITD) could be the main source of perceptual information for successfully intercepting the virtual object. The results revealed that in order to accomplish the task, one might need to vary the duration of the movement, control the hand velocity and time to reach the peak velocity (speed coupling), while the adjustment of movement initiation did not facilitate performance. Furthermore, the overall performance was more successful when subjects employed a time-to-contact (tau) coupling strategy. This result shows that prospective information is available in sound for guiding goal-directed actions.
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Propagation of intense circularly polarized laser pulses in strongly magnetized inhomogeneous plasmas is investigated. It is shown that a left-hand circularly polarized laser pulse propagating up the density gradient of the plasma along the magnetic field is reflected at the left-cutoff density. However, a right-hand circularly polarized laser can penetrate up the density gradient deep into the plasma without cutoff or resonance and turbulently heat the electrons trapped in its wake. Results from particle-in-cell simulations are in good agreement with that from the theory. (c) 2015 AIP Publishing LLC.
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Visual salience is an intriguing phenomenon observed in biological neural systems. Numerous attempts have been made to model visual salience mathematically using various feature contrasts, either locally or globally. However, these algorithmic models tend to ignore the problem’s biological solutions, in which visual salience appears to arise during the propagation of visual stimuli along the visual cortex. In this paper, inspired by the conjecture that salience arises from deep propagation along the visual cortex, we present a Deep Salience model where a multi-layer model based on successive Markov random fields (sMRF) is proposed to analyze the input image successively through its deep belief propagation. As a result, the foreground object can be automatically separated from the background in a fully unsupervised way. Experimental evaluation on the benchmark dataset validated that our Deep Salience model can consistently outperform eleven state-of-the-art salience models, yielding the higher rates in the precision-recall tests and attaining the best F-measure and mean-square error in the experiments.