Underwater Acoustics Handbook II

Albers, V. M.; Arons, A. B.

doi:10.1119/1.1973105

Cited by 24 publications

(15 citation statements)

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“…Thus, presbycusis is the most logical explanation for the hearing loss. The subject is located in Kaneohe Bay, an acoustic environment that is dominated by snapping shrimp noise and is considered to be one of the world's noisiest underwater environments (Albers, 1965). Presbycusis is often accelerated with extended exposure to high levels of background noise, so the environment of the test subject may have contributed to her presbycusis.…”

Section: Discussionmentioning

confidence: 99%

Decreased echolocation performance following high-frequency hearing loss in the false killer whale (Pseudorca crassidens)

Kloepper

Nachtigall

Gisiner³

et al. 2010

Journal of Experimental Biology

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SUMMARYToothed whales and dolphins possess a hypertrophied auditory system that allows for the production and hearing of ultrasonic signals. Although the fossil record provides information on the evolution of the auditory structures found in extant odontocetes, it cannot provide information on the evolutionary pressures leading to the hypertrophied auditory system. Investigating the effect of hearing loss may provide evidence for the reason for the development of high-frequency hearing in echolocating animals by demonstrating how high-frequency hearing assists in the functioning echolocation system. The discrimination abilities of a false killer whale (Pseudorca crassidens) were measured prior to and after documented high-frequency hearing loss. In 1992, the subject had good hearing and could hear at frequencies up to 100kHz. In 2008, the subject had lost hearing at frequencies above 40kHz. First in 1992, and then again in 2008, the subject performed an identical echolocation task, discriminating between machined hollow aluminum cylinder targets of differing wall thickness. Performances were recorded for individual target differences and compared between both experimental years. Performances on individual targets dropped between 1992 and 2008, with a maximum performance reduction of 36.1%. These data indicate that, with a loss in high-frequency hearing, there was a concomitant reduction in echolocation discrimination ability, and suggest that the development of a hypertrophied auditory system capable of hearing at ultrasonic frequencies evolved in response to pressures for fine-scale echolocation discrimination.

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Section: Discussionmentioning

confidence: 99%

Decreased echolocation performance following high-frequency hearing loss in the false killer whale (Pseudorca crassidens)

Kloepper

Nachtigall

Gisiner³

et al. 2010

Journal of Experimental Biology

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“…Several papers have suggested using nonlinear programing methods such as the least square Taylor method [ l ] and the Gauss-Newton method [2].…”

Section: Introductionmentioning

confidence: 99%

Optimal least squares time-domain synthesis of recursive digital filters

Evans

Fischl

1973

IEEE Trans. Audio Electroacoust.

116

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61(e) = u3 I #(e, dB) I -3.01~ n 12 + L n u , ] 4 9 [P(e>lP(0)12npde (11) where the weighting function w3 dB can be adjusted to yield suitable results. The usefulness of this method is somewhat limited, however, in that the value for Onull[which must still be specified in (ll)] severely restricts the range over which 6 3 d B may be influenced.Finally, the beamwidth may be controlled by keeping the current amplitudes ni fixed a t some set of values determined in the optimization program, and then merely varying the spacing between rings. This causes expansion or contraction of the radiation pattern along the horizontal scale, thus altering the beamwidth.I t should be noted here that increasing the spacing k E may introduce large sidelobes in the B= 90° region (since optimization only took pjace over a certain "visible region" in real space). Therefore, it is recommended that this approach be used only for the case where wider beamwidths are desired (i.e., with decreased spacings).As a last point, it would be instructive to consider the Abstract-A method for finding the coefficients of an nth-order linear recursive digital filter, which gives the best least squares approximation to a desired pulse response over a finite interval, is presented. A relationship is derived between the approximating error corresponding to an optimal set of numerator coefficients and the error produced by an overdetermined set of linear equations, which is a function of the denominator coefficients only. This relation provides a computational algorithm for calcularing the optimal coefficients by iteratively solving weighted sets of linear equations in terms of the denominator coefficients only. Both theoretical and numerical results are presented. Also, bounds are found on the interval in which the norm of the optimum error must lie.

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“…For instance, sound pressure is much higher in water compared to air (about 60 times; Albers 1965) for a given value of the sound intensity. Also, underwater ambient noise is highest at lower frequencies (Albers 1965). In fact, most fishes can detect only the particle displacement components associated with the sound wave (Kalmijn 1988;Roger and Cox 1988).…”

Section: Resultsmentioning

confidence: 99%

Sound Communication in Fishes

Ladich¹

2015

Animal Signals and Communication

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Underwater Acoustics Handbook II

Cited by 24 publications

References 0 publications

Decreased echolocation performance following high-frequency hearing loss in the false killer whale (Pseudorca crassidens)

Decreased echolocation performance following high-frequency hearing loss in the false killer whale (Pseudorca crassidens)

Optimal least squares time-domain synthesis of recursive digital filters

Sound Communication in Fishes

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