We study a class of acoustic metamaterials formed by layers of perforated plates and producing negative refraction and backward propagation of sound. A slab of such material is shown to act as a perfect acoustic lens, yielding images with subwavelength resolution over large distances. Our study constitutes a nontrivial extension of similar concepts from optics to acoustics, capable of sustainin...

The Stereoscopic Haptic Acoustic Real-Time Computer (SHARC) is a multi-sensory computer system which integrates technologies for autostereoscopic display, acoustic sensing and rendering, and haptic interfaces into the same computing environment. This paper describes the system organization and the interface between diierent sensory components. This paper also discusses our ndings from developin...

In demand for low-loss wide-band communication devices, Potassium niobate (KNbO3) is now receiving renewed interests because it has been found to exhibit high electromechanical coupling. This paper describes the optimum cuts of KNbO3 for bulk acoustic waves (BAW) and surface acoustic waves (SAW) devices, with expectation of their application in the future. In addition, our recent works on growt...

In this article, application of various methods for evaluating and measuring porous food structures are reviewed. It is noted, that ultrasonic vibrations and waves, due to their physical properties and wide frequency interval, can successfully be applied when analyzing porous food structures. These methods have a lot of advantages when comparing them with other non-acoustic measurement methods....

This paper is concerned with an improved network model in acoustical application to petroleum logging and seismic exploration. Utilizing acoustic-electric analogue, we report in this paper a newly developed acoustic-logging network model. Important relationships amongst various physical factors are established, i.e. driving-voltage signal, electric-acoustic conversion of source-transducer, acou...

In this paper, we discuss acoustic backing-off as a method to improve automatic speech recognition robustness. Acoustic backing-off aims to achieve the same objective as the marginalization approach of Missing Feature Theory: The detrimental influence of outlier values is effectively removed from the local distance computation in the Viterbi algorithm. The proposed method is based on one of the...

results certain correlations were found between fundamental frequency in vowel and total vhi, physical, functional and emotional domains of vhi in group 1 (r = 0.636, 0.649, 0.613 and 0.592 respectively). there was good correlation between speaking fundamental frequency and total vhi and its subscales - except the physical subscale - were also correlated. in group 2, the correlations between ji...