High frequency sound propagation in a network of interconnecting streets

Hewett, David P.

doi:10.1016/j.jsv.2012.07.030

Cited by 3 publications

(3 citation statements)

References 30 publications

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“…Another IoT-compatible localization indicator is TDoA where cross-correlations of audio signals are used to estimate the time difference of these signals. Using TDoA information from multiple sensor nodes, source localization in urban environments becomes possible [42]. Despite slightly higher edge computation requirements, TDoA based approach is an important alternative to energy based methods for urban acoustic localization especially when combined with a phase transform (GCC-PHAT) to prioritize phase over magnitude during correlation calculation.…”

Section: Related Workmentioning

confidence: 99%

Energy Neutral Urban Noise Monitoring and Classification With LoRaWAN Based IoT

2022

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Static noise maps depicting long-term noise levels over wide areas are valuable urban planning assets for municipalities in decreasing noise exposure of residents. However, non-traffic noise sources with transient behavior, which people complain frequently, are usually ignored by static maps. We propose here a dynamic noise mapping approach using the data collected via low-power wide-area network (LPWAN, specifically LoRaWAN) based internet of things (IoT) infrastructure, which is one of the most common communication backbones for smart cities. Noise mapping based on LPWAN is challenging due to the low data rates of these protocols. The proposed dynamic noise mapping approach diminishes the negative implications of data rate limitations using machine learning (ML) for event and location prediction of non-traffic sources based on the scarce data. The strength of these models lies in their consideration of the spatial variance in acoustic behavior caused by the buildings in urban settings. The effectiveness of the proposed method and the accuracy of the resulting dynamic maps are evaluated in field tests. The results show that the proposed system can decrease the map error caused by non-traffic sources up to 51% and can stay effective under significant packet losses.

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Section: Related Workmentioning

confidence: 99%

Energy Neutral Urban Noise Monitoring and Classification With LoRaWAN Based IoT

2022

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“…This appears to be the first edge source representation for diffraction by an impedance wedge. While the solution obtained is valid only for a right-angled wedge, it should be remarked that this special case is ubiquitous in many acoustical applications (e.g., urban acoustics 16 ).…”

Section: Introductionmentioning

confidence: 99%

Diffraction by a right-angled impedance wedge: An edge source formulation

Hewett

2015

The Journal of the Acoustical Society of America

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This paper concerns the frequency domain problem of diffraction of a plane wave incident on an infinite right-angled wedge on which impedance (absorbing) boundary conditions are imposed. It is demonstrated that the exact Sommerfeld-Malyuzhinets contour integral solution for the diffracted field can be transformed to a line integral over a physical variable along the diffracting edge. This integral can be interpreted as a superposition of secondary point sources (with directivity) positioned along the edge, in the spirit of the edge source formulations for rigid (sound-hard) wedges derived by Svensson et al. [Acta Acust. Acust. 95, 568-572 (2009)]. However, when surface waves are present the physical interpretation of the edge source integral must be altered: it no longer represents solely the diffracted field, but rather it includes surface wave contributions.

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“…CNOSSOS-EU, ISO 9613-2 14 , and Harmonoise 15,16 ) because they are not designed to model such complex shapes and geometrical approaches more generally (e.g. ray tracing 17,18 or beam tracing 19,20 ) because these complex shapes would require too many diffracting edges to model them efficiently. In addition, the parabolic equation method 21,22 cannot model such complex geometries because it usually only models one-way propagation 23 to improve computational efficiency.…”

Section: Introductionmentioning

confidence: 99%

Extending standard urban outdoor noise propagation models to complex geometries

Kamrath

Jean

Maillard

et al. 2018

The Journal of the Acoustical Society of America

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A hybrid method that combines a noise engineering method and the 2.5D boundary element method approximates outdoor sound propagation in large domains with complex objects more accurately than noise engineering methods alone and more efficiently than reference methods alone. Noise engineering methods (e.g., ISO 9613-2 or CNOSSOS-EU) efficiently approximate sound levels from roads, railways, and industrial sources in cities for simple, box-shaped geometries by first finding the propagation paths between the source and receiver, then applying attenuations (e.g., geometrical divergence and atmospheric absorption) to each path, and finally incoherently summing all of the path contributions. Standard engineering methods cannot model more complicated geometries but introducing an additional attenuation term quantifies the influence of complex objects. Calculating this extra attenuation term requires reference calculations but performing reference computations for each path is too computationally expensive. Thus, the extra attenuation term is linearly interpolated from a data table containing the corrections for many source/receiver positions and frequencies. The 2.5D boundary element method produces the levels for the real and simplified geometries and subtracting them yields a table of corrections. For a T-shaped barrier with two buildings, this approach reduces the mean error by approximately 2 dBA compared to a standard engineering method.

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High frequency sound propagation in a network of interconnecting streets

Cited by 3 publications

References 30 publications

Energy Neutral Urban Noise Monitoring and Classification With LoRaWAN Based IoT

Energy Neutral Urban Noise Monitoring and Classification With LoRaWAN Based IoT

Diffraction by a right-angled impedance wedge: An edge source formulation

Extending standard urban outdoor noise propagation models to complex geometries

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