Modeling RF and acoustic signal propagation in complex environments

2018 ◽  
Author(s):  
D. Keith Wilson ◽  
Daniel J. Breton ◽  
Wesley M. Barnes ◽  
Michael B. Muhlestein ◽  
Vladimir E. Ostashev ◽  
...  
Keyword(s):  
Acoustic Signal ◽  
Signal Propagation ◽  
Complex Environments

scholarly journals Researches on very low frequency acoustic signal propagation characteristics in different shallow elastic wedge bottoms

2019 ◽  
Vol 283 ◽  
pp. 02003
Author(s):  
Jun Zhu ◽  
Hanhao Zhu ◽  
Jun Tang ◽  
Guangxue Zheng
Keyword(s):  
Acoustic Signal ◽  
Low Frequency ◽  
Signal Propagation ◽  
Acoustic Energy ◽  
Propagation Characteristics ◽  
The Finite Element Method ◽  
Very Low Frequency ◽  
Extremely Low Frequency ◽  
Elastic Bottom ◽  
Sloping Bottom

Targeted at the issue of extremely low-frequency (<100Hz) acoustic propagation in complex shallow elastic bottom environments. The influence law of different complex elastic bottoms on the acoustic signal propagation at very low frequency by acoustic energy flux has been analyzed with the simulation, which is based on the finite element method. The elastic bottoms which have been studied are the shallow horizontal elastic bottom, and the up-sloping and the down-sloping elastic bottom. The results show that the acoustic signal propagating in the up-sloping and down-sloping elastic bottom environments is more complex than that propagating in the horizontal elastic bottom, and the acoustic energy leaking into those elastic bottoms has very different influence on the acoustic signal propagation, especially in the up-sloping bottom.

Statistical moments for wideband acoustic signal propagation through a turbulent atmosphere

2014 ◽  
Vol 136 (4) ◽  
pp. 2139-2139
Author(s):  
Jericho E. Cain ◽  
Sandra L. Collier ◽  
Vladimir E. Ostashev ◽  
David K. Wilson
Keyword(s):  
Acoustic Signal ◽  
Turbulent Atmosphere ◽  
Signal Propagation ◽  
Statistical Moments

Study of Acoustic Signal Propagation from Sea to Land

2019 ◽  
Vol 65 (3) ◽  
pp. 279-287
Author(s):  
A. N. Rutenko ◽  
D. S. Manul’chev ◽  
S. B. Kozitskii
Keyword(s):  
Acoustic Signal ◽  
Signal Propagation

An acoustic signal propagation experiment beneath sea ice

2012 ◽  
Vol 43 ◽  
pp. 56-63 ◽  
Author(s):  
Ron S. Lewis ◽  
Michèle Drogou ◽  
Peter King ◽  
George Mann ◽  
Neil Bose ◽  
...  
Keyword(s):  
Sea Ice ◽  
Acoustic Signal ◽  
Signal Propagation ◽  
Propagation Experiment

scholarly journals Characterization of In-Pipe Acoustic Wave for Water Leak Detection

2011 ◽  
Author(s):  
Atia E. Khalifa ◽  
Rached Ben-Mansour ◽  
Kamal Youcef-Toumi ◽  
Changrak Choi
Keyword(s):  
Acoustic Signal ◽  
Acoustic Waves ◽  
Wave Attenuation ◽  
Signal Propagation ◽  
Optimum Location ◽  
Flow Conditions ◽  
Water Leak ◽  
Flexible Pipes ◽  
Line Pressure

This paper presents experimental observations on the characteristics of the acoustic signal propagation and attenuation inside water-filled pipes. An acoustic source (exciter) is mounted on the internal pipe wall, at a fixed location, and produces a tonal sound to simulate a leak noise with controlled frequency and amplitude, under different flow conditions. A hydrophone is aligned with the pipe centerline and can be re-positioned to capture the acoustic signal at different locations. Results showed that the wave attenuation depends on the source frequency and the line pressure. High frequency signals get attenuated more with increasing distance from the source. The optimum location to place the hydrophone for capturing the acoustic signal is not at the vicinity of source location. The optimum location also depends on the frequency and line pressure. It was also observed that the attenuation of the acoustic waves is higher in more flexible pipes like PVC ones.

scholarly journals Sympatric wren-warblers partition acoustic signal space and song perch height

2020 ◽  
Vol 31 (2) ◽  
pp. 559-567 ◽  
Author(s):  
Shivam S Chitnis ◽  
Samyuktha Rajan ◽  
Anand Krishnan
Keyword(s):  
Acoustic Signal ◽  
Community Organization ◽  
Ecological Factors ◽  
Signal Propagation ◽  
Acoustic Signals ◽  
Sympatric Species ◽  
Niche Separation ◽  
Space Partitioning ◽  
Signal Space ◽  
Ecological Processes

Abstract Animals employing acoustic signals, such as birds, must effectively communicate over both background noise and potentially attenuating objects in the environment. To surmount these obstacles, animals evolve species-specific acoustic signals that do not overlap with sources of interference (such as songs of close relatives), and issue these songs from locations that maximize transmission. In multispecies assemblages of birds, the acoustic resource may thus be interspecifically partitioned along multiple axes, including song perch height and signal space. However, very few such studies have focused on open habitats, where differences in sound transmission patterns and limited availability of song perches may drive competition across multiple axes within signal space. Here, we demonstrate acoustic signal space partitioning in four sympatric species of wren-warbler (Cisticolidae, Prinia), in an Indian dry deciduous scrub-grassland habitat. We found that the breeding songs of the four species partition acoustic signal space, resulting in interspecific community organization. Within each species’ signal space, we uncovered different intraspecific patterns in note diversity. Two species partition intraspecific signal space into multiple note types, whereas the other two vary note repetition rate to different extents. Finally, we found that the four species also partition song perch heights, thus exhibiting acoustic niche separation along multiple axes. We hypothesize that divergent song perch heights may be driven by competition for higher singing perches or other ecological factors rather than signal propagation. Acoustic signal partitioning along multiple axes may therefore arise from a combination of diverse ecological processes.

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