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You searched for subject:(Pinna Motions). Showing records 1 – 2 of 2 total matches.

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Virginia Tech

1. Qiu, Peiwen. Variability in the Pinna Motions of Hipposiderid Bats, Hipposideros Pratti.

Degree: MS, Mechanical Engineering, 2020, Virginia Tech

Sensors have been developed for a long time, and they can be used to detect the environments and then deliver the required sensing information. There are many different types of sensors, such as vision-based sensors (infrared camera and laser scanner) and sound-based sensors (sonar and radar). Ultrasonic transducers are one of the sound-based sensors, and they are more stable and reliable in environments where smoke or steam is present. Similar to human-made ultrasonic transducers, bats have developed highly capable biosonar systems that consist of one ultrasonic emitter (nose or mouth) and two ultrasonic receivers (ears), and these biosonar systems enable them to fly and hunt in cluttered environments. Some bats, e.g. rhinolophid and hipposiderid bats, have dynamic noseleaves (elaborate baffle shapes surrounding the nostrils) and pinna (outer ear), and these could enhance the sensing abilities of bats. Hence, the purpose of this thesis has been to investigate this variability to improve the human-made sensors by focusing on the dynamic pinna of the bats. It has been shown that bats have two distinct categories of pinna motions: rigid motions which change only the orientation of the pinna, and non-rigid motions which change also the shape of the pinna. However, the variability within the rigid and non-rigid pinna motions has received little attention. Therefore, the present work has investigated the variability in the rigid pinna motions and in the non-rigid pinna motions. Landmark points were placed on the pinna of certain bats and the pinna motions were tracked by high-speed video cameras. The rigid pinna motions exhibit a large continuous variation in where the pinna is orientated during rotation. Distributions of clusters of the landmarks on the pinna have shown that the non-rigid pinna motions fall into at least two subgroups. The acoustic impacts of the rigid pinna motions have been studied by a biomimetic pinna which reproduced the observed range of the rigid pinna motions. Ultrasonic signals mimicking the bats were emitted to be received by the biomimetic pinna. Based on these signals, it has been shown that different rotation axes and even small changes can provide over 50% new sensory information. These findings give engineers a potential way to improve the human-made sensors. Advisors/Committee Members: Mueller, Rolf (committeechair), Kekatos, Vasileios (committee member), Leonessa, Alexander (committee member).

Subjects/Keywords: Bat biosonar; pinna motions; dynamic sensing; sensory information encoding

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Qiu, P. (2020). Variability in the Pinna Motions of Hipposiderid Bats, Hipposideros Pratti. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/96483

Chicago Manual of Style (16th Edition):

Qiu, Peiwen. “Variability in the Pinna Motions of Hipposiderid Bats, Hipposideros Pratti.” 2020. Masters Thesis, Virginia Tech. Accessed February 28, 2021. http://hdl.handle.net/10919/96483.

MLA Handbook (7th Edition):

Qiu, Peiwen. “Variability in the Pinna Motions of Hipposiderid Bats, Hipposideros Pratti.” 2020. Web. 28 Feb 2021.

Vancouver:

Qiu P. Variability in the Pinna Motions of Hipposiderid Bats, Hipposideros Pratti. [Internet] [Masters thesis]. Virginia Tech; 2020. [cited 2021 Feb 28]. Available from: http://hdl.handle.net/10919/96483.

Council of Science Editors:

Qiu P. Variability in the Pinna Motions of Hipposiderid Bats, Hipposideros Pratti. [Masters Thesis]. Virginia Tech; 2020. Available from: http://hdl.handle.net/10919/96483


Virginia Tech

2. Yin, Xiaoyan. The Role of Actively Created Doppler shifts in Bats Behavioral Experiments and Biomimetic Reproductions.

Degree: PhD, Mechanical Engineering, 2021, Virginia Tech

Bats are well-known for their intricate biosonar system that allow the animals to navigate even the most complex natural environments. While the mechanism behind most of these abilities remains unknown, an interesting observation is that some bat species produce fast movements of their ears when actively exploring their surroundings. By moving their pinna, the bats create a time-variant reception characteristic and very little research has been directed at exploring the potential benefits of such behavior so far. One hypothesis is that the speed of the pinna motions modulates the received biosonar echoes with Doppler-shift patterns that could convey sensory information that is useful for navigation. This dissertation intends to explore this hypothetical dynamic sensing mechanism by building a soft-robotic biomimetic receiver to replicate the dynamics of the bat pinna. The experiments with this biomimetic pinna robot demonstrate that the non-rigid ear motions produce Doppler signatures that contain information about the direction of a sound source. However, these patterns are difficult to interpret because of their complexity. By combining the soft-robotic pinna with a convolutional neural network for processing the Doppler signatures in the time-frequency domain, I have been able to accurately estimate the source direction with an error margin of less than one degree. This working system, composed of a soft-robotic biomimetic ear integrated with a deep neural net, demonstrates that the use of Doppler signatures as a source of sensory information is a viable hypothesis for explaining the sensory skills of bats. Advisors/Committee Members: Mueller, Rolf (committeechair), Socha, John (committee member), Leonessa, Alexander (committee member), Abaid, Nicole Teresa (committee member), Roan, Michael J. (committee member).

Subjects/Keywords: Bats; Biosonar; Pinna Motions; Doppler Shifts; Direction finding; Biomimetics; Deep Learning

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Yin, X. (2021). The Role of Actively Created Doppler shifts in Bats Behavioral Experiments and Biomimetic Reproductions. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/101965

Chicago Manual of Style (16th Edition):

Yin, Xiaoyan. “The Role of Actively Created Doppler shifts in Bats Behavioral Experiments and Biomimetic Reproductions.” 2021. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021. http://hdl.handle.net/10919/101965.

MLA Handbook (7th Edition):

Yin, Xiaoyan. “The Role of Actively Created Doppler shifts in Bats Behavioral Experiments and Biomimetic Reproductions.” 2021. Web. 28 Feb 2021.

Vancouver:

Yin X. The Role of Actively Created Doppler shifts in Bats Behavioral Experiments and Biomimetic Reproductions. [Internet] [Doctoral dissertation]. Virginia Tech; 2021. [cited 2021 Feb 28]. Available from: http://hdl.handle.net/10919/101965.

Council of Science Editors:

Yin X. The Role of Actively Created Doppler shifts in Bats Behavioral Experiments and Biomimetic Reproductions. [Doctoral Dissertation]. Virginia Tech; 2021. Available from: http://hdl.handle.net/10919/101965

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