An acoustic head simulator for hearing protector evaluation. II: Measurements in steady‐state and impulse noise environments

1989 ◽  
Vol 85 (3) ◽  
pp. 1197-1205 ◽  
Author(s):  
Christian Giguère ◽  
Hans Kunov
Keyword(s):  
Steady State ◽  
Impulse Noise ◽  
Hearing Protector

Rating of Hearing Protector Performance for Impulse Noise

1993 ◽  
Author(s):  
Daniel L. Johnson ◽  
James H. Patterson ◽  
Jr
Keyword(s):  
Impulse Noise ◽  
Hearing Protector

scholarly journals A Kernel-Width Adaption Diffusion Maximum Correntropy Algorithm

2020 ◽  
Author(s):  
Ying Guo ◽  
Bing Ma ◽  
Yingsong Li
Keyword(s):  
Steady State ◽  
Impulse Noise ◽  
Kernel Width ◽  
Sparse System ◽  
Initial Stage ◽  
Small Kernel ◽  
Sparse Systems ◽  
Simulation Results ◽  
Maximum Correntropy Criterion ◽  
Large Kernel

In this paper, a diffusion maximum correntropy criterion (DMCC) algorithm with adaption kernel width is proposed, denoting as DMCC$_{\rm adapt}$ algorithm, to find out a solution for dynamically choosing the kernel width. The DMCC$_{\rm adapt}$ algorithm chooses small kernel width at initial stage to improve its convergence speed rate, and uses large kernel width at completion stage to reduce its steady-state error. To render the proposed DMCC$_{\rm adapt}$ algorithm suitable for sparse system identifications, the DMCC$_{\rm adapt}$ algorithm based on proportional coefficient adjustment is realized and named as diffusion proportional maximum correntropy criterion (DPMCC$_{\rm adapt}$). The theoretical analysis and simulation results are presented to show that the DPMCC$_{\rm adapt}$ and DMCC$_{\rm adapt}$ algorithms have better convergence than the traditional diffusion AF algorithms under impulse noise and sparse systems.

scholarly journals Preloaded D-methionine protects from steady state and impulse noise-induced hearing loss and induces long-term cochlear and endogenous antioxidant effects

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261049
Author(s):  
Kathleen Campbell ◽  
Nicole Cosenza ◽  
Robert Meech ◽  
Michael Buhnerkempe ◽  
Jun Qin ◽  
...  
Keyword(s):  
Steady State ◽  
Impulse Noise ◽  
Noise Exposure ◽  
Time Window ◽  
Auditory Brainstem ◽  
Threshold Shift ◽  
Time Points ◽  
Starting Time ◽  
Brainstem Response ◽  
Time Point

Objective Determine effective preloading timepoints for D-methionine (D-met) otoprotection from steady state or impulse noise and impact on cochlear and serum antioxidant measures. Design D-met started 2.0-, 2.5-, 3.0-, or 3.5- days before steady-state or impulse noise exposure with saline controls. Auditory brainstem response (ABRs) measured from 2 to 20 kHz at baseline and 21 days post-noise. Samples were then collected for serum (SOD, CAT, GR, GPx) and cochlear (GSH, GSSG) antioxidant levels. Study sample Ten Chinchillas per group. Results Preloading D-met significantly reduced ABR threshold shifts for both impulse and steady state noise exposures but with different optimal starting time points and with differences in antioxidant measures. For impulse noise exposure, the 2.0, 2.5, and 3.0 day preloading start provide significant threshold shift protection at all frequencies. Compared to the saline controls, serum GR for the 3.0 and 3.5 day preloading groups was significantly increased at 21 days with no significant increase in SOD, CAT or GPx for any impulse preloading time point. Cochlear GSH, GSSG, and GSH/GSSG ratio were not significantly different from saline controls at 21 days post noise exposure. For steady state noise exposure, significant threshold shift protection occurred at all frequencies for the 3.5, 3.0 and 2.5 day preloading start times but protection only occurred at 3 of the 6 test frequencies for the 2.0 day preloading start point. Compared to the saline controls, preloaded D-met steady-state noise groups demonstrated significantly higher serum SOD for the 2.5–3.5 day starting time points and GPx for the 2.5 day starting time but no significant increase in GR or CAT for any preloading time point. Compared to saline controls, D-met significantly increased cochlear GSH concentrations in the 2 and 2.5 day steady-state noise exposed groups but no significant differences in GSSG or the GSH/GSSG ratio were noted for any steady state noise-exposed group. Conclusions The optimal D-met preloading starting time window is earlier for steady state (3.5–2.5 days) than impulse noise (3.0–2.0). At 21 days post impulse noise, D-met increased serum GR for 2 preloading time points but not SOD, CAT, or GpX and not cochlear GSH, GSSG or the GSH/GSSG ratio. At 21 days post steady state noise D-met increased serum SOD and GPx at select preloading time points but not CAT or GR. However D-met did increase the cochlear GSH at select preloading time points but not GSSG or the GSH/GSSG ratio.

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