The structural state of a bridge is currently examined by visual inspection or by wired sensor techniques, which are relatively expensive, vulnerable to inclement conditions, and time consuming to undertake. In contrast, wireless sensor networks are easy to deploy and flexible in application so that the network can adjust to the individual structure. Different sensing techniques have been used ...

A one dimensional system made up of a compressible fluid and several mechanical oscillators, coupled to the acoustic field in the fluid, is analyzed for different settings of the oscillators array. The dynamical models are formulated in terms of singular perturbations of the decou-pled dynamics of the acoustic field and the mechanical oscillators. Detailed spectral properties of the generators ...

In this paper, methods are presented to design an acoustic source array for both directional sound generation and non-directional sound generation. The methods are based on measured transfer functions to be able to take into account different source sensitivities, to use extended sources that cannot be regarded as point sources, and complex geometries modifying the radiation characteristics. Th...

The Pacific Ocean Shelf Tracking (POST) project was established as one of the 17 projects of the decade-long Census of Marine Life. Its initial purpose was to improve our understanding of the distribution and life history of salmon on the continental shelf. POST was made possible by developments in acoustic technology which resulted in miniaturization of acoustic tags along with the creation of...

A real-time 32-element synthetic aperture acoustic imaging system has been developed. We can test new ideas for the system by using an acoustic array and carrying out image reconstruction on a computer. Contour plots of simple images are shown to illustrate the resolution (0.4 0.5 mm in range and transverse resolution) and sidelobe levels obtained with this synthetic-aperture technique. Rayleig...

Abstract: Wide area acoustic remote sensing often involves the use of coherent receiver arrays to determine the spatial distribution of sources and scatterers at any instant. The resulting acoustic intensity images are typically corrupted by signal-dependent noise from Gaussian random field fluctuations arising from the central limit theorem and have a spatial resolution that depends on the inc...

This paper summarizes a case study example on the methodology used for phased array microphone measurements in a realistic acoustic environment. A ducted fan rotor is measured in an environment, where structure born noise and aerodynamically generated noise cannot be separated using conventional single microphone acoustic analysis. The conditions of the measurement are similar to an industrial ...

This chapter reviews distant speech recognition experimentation using the AMI Corpus of multiparty meetings. The chapter compares conventional approaches using microphone array beamforming followed by single-channel acoustic modelling with approaches which combine multichannel signal processing with acoustic modelling in the context of convolutional networks.

Loudspeaker arrays are increasingly being used in a variety of applications where there is a restriction on the electrical power consumption and the array must be robust to changes in the acoustic environment. Previous work has demonstrated that the efficiency and robustness of a two-source endfire loudspeaker array can be improved by acoustically coupling the two loudspeakers via a common encl...