Quantitative approaches to sensory information encoding by bat noseleaves and pinnae

Müller, Rolf

doi:10.1139/cjz-2017-0117

Cited by 4 publications

(2 citation statements)

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“…In addition to the static geometric complexity of the biosonar periphery, there are dynamic changes to the shapes of the noseleaves and pinnae as a result of fast muscular actuation [19][20][21][22]. These active deformations add a dynamic dimension to the encoding of sensory information, which would be a novel functional principle for technical sensors [23][24][25][26][27]. Results from numerical beampattern predictions have indicated that noseleaves have an effect on the shape of the emission patterns [15,17,28].…”

Section: Introductionmentioning

confidence: 99%

Design of a dynamic sonar emitter inspired by hipposiderid bats

Yang

Yu²,

Müller

2018

Bioinspir. Biomim.

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The ultrasonic emission of the biosonar systems of bats, such as Old World leaf-nosed bats (family Hipposideridae) and the related horseshoe bats (family Rhinolophidae), is characterized by a unique dynamics where baffle shapes ('noseleaves') deform while diffracting the outgoing wave packets. As of now, nothing comparable to this dynamics has been used in any related engineering application (e.g. sonar or radar). Prior work with simple concave baffle shapes has demonstrated the impact of the dynamics on the emission characteristics, but it has remained unclear whether this was simply due to the change in aperture size or also influenced by the geometrical shape detail. Hence, it has also remained unclear whether it would be possible to further enhance the time-variant effects reported so far through different static and dynamic geometries. To address this issue, we have created a dynamic emission baffle with biomimetic shape detail modeled after Pratt's roundleaf bats (Hipposideros pratti). The impact of the dynamic deformation of the shape on the time-variant emission characteristics was evaluated by virtue of the gradient magnitude and the entropy in the gradient orientation. The results have shown that the dynamics results in much larger gradients in signal representation, which change jointly over direction and time.

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Section: Introductionmentioning

confidence: 99%

Design of a dynamic sonar emitter inspired by hipposiderid bats

Yang

Yu²,

Müller

2018

Bioinspir. Biomim.

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“…These capabilities allow the bats to thrive in dense vegetation and offer valuable insights in technical sensing paradigms, sonar or otherwise. The significance of bat biosonar for engineering has been published elsewhere [16], [17]. In addition to gaining research experience, the IRES students participated in seminars and field trips during 8-week period in China.…”

Section: China Iresmentioning

confidence: 99%

Student Learning in International Research Programs: A Comparison Across Cultural Contexts

Davis

Jalali

Knight

et al.

2018 ASEE Annual Conference &Amp; Exposition Proceedings

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is a doctoral candidate in the Department of Engineering Education at Virginia Tech, where she also completed her master's degree in Higher Education. She is the graduate assistant for the Rising Sophomore Abroad Program, a global engineering course and study abroad program for first year engineering students. Her primary research interests are engineering study abroad, developing intercultural competency in engineering students, and international higher education.

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Fast-moving bat ears create informative Doppler shifts

Yin

Müller

2019

Proc. Natl. Acad. Sci. U.S.A.

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Many animals have evolved adept sensory systems that enable dexterous mobility in complex environments. Echolocating bats hunting in dense vegetation represent an extreme case of this, where all necessary information about the environment must pass through a parsimonious channel of pulsed, 1D echo signals. We have investigated whether certain bats (rhinolophids and hipposiderids) actively create Doppler shifts with their pinnae to encode additional sensory information. Our results show that the bats' active pinna motions are a source of Doppler shifts that have all attributes required for a functional relevance: (i) the Doppler shifts produced were several times larger than the reported perception threshold; (ii) the motions of the fastest moving pinna portions were oriented to maximize the Doppler shifts for echoes returning from the emission direction, indicating a possible evolutionary optimization; (iii) pinna motions coincided with echo reception; (iv) Doppler-shifted signals from the fast-moving pinna portion entered the ear canal of a biomimetic pinna model; and (v) the time-frequency Doppler shift signatures were found to encode target direction in an orderly fashion. These results indicate that instead of avoiding or suppressing all self-produced Doppler shifts, rhinolophid and hipposiderid bats actively create Doppler shifts with their own pinnae. These bats could hence make use of a previously unknown nonlinear mechanism for the encoding of sensory information, based on Doppler signatures. Such a mechanism could be a source for the discovery of sensing principles not only in sensory physiology but also in the engineering of sensory systems.biosonar | ear motions | Doppler shifts | time-frequency signatures | nonlinear sensing C onspicuous pinna motions (1-5) are an integral part of biosonar behaviors in horseshoe bats and Old World leafnosed bats [families Rhinolophidae and Hipposideridae (6, 7)]. These motions have been demonstrated to enhance sensing and navigation performance (8-10), but the functional role of these dynamic features and the underlying mechanisms have yet to be fully understood (7). In the acoustic domain, source or receiver motions can result in Doppler shifts, i.e., nonlinear scaling of signals in time and frequency. The possibility of pinna-induced Doppler shifts had been mentioned as an aside in early work by Pye and coworkers (2, 3, 11) but has not been considered further-let alone investigated in any depthin the literature since. This complete neglect is regrettable, because ear-generated Doppler shifts could constitute a previously unknown, nonlinear mechanism for the active encoding of sensory information. To test this hypothesis, we have carried out a quantitative experimental investigation of the hypothesis that pinna motions cause functionally relevant Doppler shifts in bats. For pinna-generated Doppler shifts to have a functional role, five necessary conditions must be met: (i) pinna surface speeds must be high enough to produce Doppler shifts that exceed the animal's per...

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Quantitative approaches to sensory information encoding by bat noseleaves and pinnae

Cited by 4 publications

References 51 publications

Design of a dynamic sonar emitter inspired by hipposiderid bats

Design of a dynamic sonar emitter inspired by hipposiderid bats

Student Learning in International Research Programs: A Comparison Across Cultural Contexts

Fast-moving bat ears create informative Doppler shifts

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