The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Nader Behdad - One of the best experts on this subject based on the ideXlab platform.
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Biomimetic Antenna Arrays Based on the Directional Hearing Mechanism of the Parasitoid Fly Ormia Ochracea
IEEE Transactions on Antennas and Propagation, 2013Co-Authors: Amir R. Masoumi, Yazid Yusuf, Nader BehdadAbstract:We present a thorough examination of two-element antenna arrays that mimic the sense of Directional Hearing of the parasitoid fly Ormia Ochracea and examine the design tradeoffs of such arrays. Recently, it was demonstrated that these antenna arrays demonstrate enhanced sensitivity to the direction of incidence of an electromagnetic wave, compared to regular arrays occupying the same aperture. This, however, comes at the expense of sacrificing the available power at the outputs of such arrays. In this paper, we present a model for these two-element biomimetic antenna arrays (BMAAs) that takes the mutual coupling effects into account. Using this model, we examine the tradeoffs that exist between the phase enhancement, which can be achieved from these arrays, and their output power levels. We demonstrate that for any given desired phase enhancement factor, an optimum BMAA design exists that maximizes the output power level of the array. We also show that strong mutual coupling between the two antennas can be exploited to enhance the output power of the array. A method for designing practical two-element BMAAs is also presented along with simulation and measurement results of a fabricated prototype.
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On the design and optimization of biomimetic electrically small antenna arrays
2012 IEEE International Workshop on Antenna Technology (iWAT), 2012Co-Authors: Nader Behdad, Amir Reza Masoumi, Yazid YusufAbstract:Many small animals and insects possess acute Directional Hearing capabilities and are able to localize sound sources of interest with an astonishing degree of precision. The auditory systems of such insects are analogous to a two-element antenna array with closely spaced receiving elements. Despite this close spacing, however, the insects can detect the direction of arrival of a sound wave with an amazing degree of precision. In this paper, we discuss electrically small antenna arrays that mimic the sense of Directional Hearing of small animals and discuss the important design considerations and that must be taken into account in designing these structures.
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Biomimetic electrically small antennas
Electronics Letters, 2010Co-Authors: Nader Behdad, Mudar A Al-joumayly, Meng LiAbstract:Many insects possess acute Directional Hearing capabilities and are able to localise a sound source of interest with a good degree of precision. An analogy can be drawn between the Hearing mechanisms of such insects and a two-element, electrically small antenna array. Presented is a biomimetic electrically small antenna array that mimics the Hearing mechanism of an insect with hyperacute Directional Hearing capability. A prototype of such an antenna has been fabricated and its simulated and measured results are presented. Such biomimetic antenna arrays could be used in numerous applications ranging from miniaturised RF sensors and direction finding systems to small aperture, high-resolution microwave imaging systems and radars.
Daniel Robert - One of the best experts on this subject based on the ideXlab platform.
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innovative biomechanics for Directional Hearing in small flies
The Biological Bulletin, 2001Co-Authors: Daniel RobertAbstract:In humans and animals alike, the localization of sound constitutes a fundamental processing task of the auditory system. Directional Hearing relies on acoustic cues such as the interaural amplitude and time differences and also, sometimes, the signal spectral composition. In small animals, such as insects, the auditory receptors are forcibly set close together, a design constraint imposing very short interaural distances. Due to the physics of sound propaga- tion, the close proximity of the sound receivers results in vanishingly small amplitude and time cues. Yet, because of their Directionality, small auditory systems embed original and innovative solutions that can be of inspirational value to some acute problems of technological miniaturization. Such ears are found in a parasitoid fly that acoustically locates its singing cricket host. Anatomically rather unconventional, the fly's auditory system is endowed with a Directional sensitivity that is based on the mechanical coupling between its two hemilateral tympanal membranes. The functional principle permitting this Directionality may be of particular relevance for technological applications necessitating sen- sors that are low cost, low weight, and low energy. Based on silicon-etching technology, early prototypes of sub-millime- ter acoustic sensors provide evidence for Directional me- chanical responses. Further developments hold the promise of applications in Hearing aid technology, vibration sensors, and miniature video-acoustic surveillance systems.
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Directional Hearing in small animals: Tympanal mechanics and evolutionary innovations
Journal of the Acoustical Society of America, 1999Co-Authors: Daniel RobertAbstract:Tympanal Hearing is an evolutionary innovation that occurred at least twice independently in flies (Diptera). Both in Tachinidae and Sarcophagidae fly families, Hearing organs evolved that are located on the anterior thorax and that present two thin tympanal membranes rigidly connecting to a pair of mechano‐receptive sensory organs. Remarkably, the small interaural distance (1 mm) constitutes a serious challenge for Directional Hearing at 3–6 kHz. The mechanical response of these ears to incident random noise was investigated by microscanning laser Doppler vibrometry. Mechanical transfer functions of tympanal displacements show that the ipsi‐ and contralateral tympana vibrate with an unexpectedly large amplitude difference and interaural delay [R. N. Miles et al., J. Acoust. Soc. Am. 98, 3059–3070 (1995)]. The deflection shape analysis shows that in both cases the tympanal membranes are mechanically coupled across the animals midline. However, morphological and biomechanical evidence indicates that the pr...
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Directional Hearing by mechanical coupling in the parasitoid fly Ormia ochracea
Journal of Comparative Physiology A, 1996Co-Authors: Daniel Robert, Ronald N. MilesAbstract:Sound localization is a basic processing task of the auditory system. The Directional detection of an incident sound impinging on the ears relies on two acoustic cues: interaural amplitude and interaural time differences. In small animals, with short interaural distances both amplitude and time cues can become very small, challenging the Directional sensitivity of the auditory system. The ears of a parasitoid fly Ormia ochracea , are unusual in that both acoustic sensors are separated by only 520 μm and are contained within an undivided air-filled chamber. This anatomy results in minuscule differences in interaural time cues (ca. 2 μs) and no measurable difference in interaural intensity cues generated from an incident sound wave. The tympana of both ears are anatomically coupled by a cuticular bridge. This bridge also mechanically couples the tympanana, providing a basis for Directional sensitivity. Using laser vibrometry, it is shown that the mechanical response of the tympanal membranes has a pronounced Directional sensitivity. Interaural time and intensity differences in the mechanical response of the ears are significantly larger than those available in the acoustic field. The tympanal membranes vibrate with amplitude differences of about 12 dB and time differences on the order of 50 μs to sounds at 90° off the longitudinal body axis. The analysis of the deflection shapes of the tympanal vibrations shows that the interaural differences in the mechanical response are due to the dynamic properties of the tympanal system and reflect its intrinsic sensitivity to the direction of a sound source. Using probe microphones and extracellular recording techniques, we show that the primary auditory afferents encode sound direction with a time delay of about 300 μs. Our data point to a novel mechanism for Directional Hearing in O. ochracea based on intertympanal mechanical coupling, a process that amplifies small acoustic cues into interaural time and amplitude differences that can be reliably processed at the neural level. An intuitive description of the mechanism is proposed using a simple mechanical model in which the ears are coupled through a flexible lever.
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mechanically coupled ears for Directional Hearing in the parasitoid fly ormia ochracea
Journal of the Acoustical Society of America, 1995Co-Authors: Ronald N. Miles, Daniel RobertAbstract:An analysis is presented of the mechanical response to a sound field of the ears of the parasitoid fly Ormia ochracea. This animal shows a remarkable ability to detect the direction of an incident sound stimulus even though its acoustic sensory organs are in very close proximity to each other. This close proximity causes the arrival times of the sound pressures at the two ears to be less than 1 to 2 μs depending on the direction of propagation of the sound wave. The small differences in these two pressures must be processed by the animal in order to determine the incident direction of the sound. In this fly, the ears are so close together that they are actually joined by a cuticular structure which couples their motion mechanically and subsequently magnifies interaural differences. The use of a cuticular structure as a means to couple the ears to achieve Directional sensitivity is novel and has not been reported in previous studies of Directional Hearing. An analytical model of the mechanical response of ...
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A novel mechanism for Directional Hearing in a parasitoid fly
Journal of the Acoustical Society of America, 1994Co-Authors: Daniel Robert, Ronald N. MilesAbstract:Sound localization is a basic behavioral task of the auditory system. Incident sound waves arrive at the ears and generate interaural differences in time of arrival and in amplitude that are key cues for the computation of sound direction. In small animals, both cues can become vanishingly small, posing a challenge for Directional Hearing. Yet nearly all animals that hear can localize sound. In the fly Ormia ochracea, the two acoustic sensors are separated by only about 520 μm, and are contained within an undivided air‐filled chamber, an arrangement that results in minimal differences in interaural time (
Todd A. Ricketts - One of the best experts on this subject based on the ideXlab platform.
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Directional Hearing aid benefit in listeners with severe Hearing loss.
International Journal of Audiology, 2020Co-Authors: Todd A. Ricketts, Benjamin W. Y. HornsbyAbstract:The purpose of this investigation was to examine the potential for Directional Hearing aid benefit in listeners with severe Hearing loss at multiple SNRs for both auditory only and audio-visual presentation modes. Speech recognition performance was measured using the connected speech test at six SNRs individually determined for each subject in order to avoid floor and ceiling effects. The results revealed significant Directional benefit was present at all tested SNRs in the presence of visual information. For auditory only presentations, significant Directional benefit was only present at the least positive SNR. The largest Directional benefit was measured at the poorest tested SNR for both auditory only and audio-visual presentation modes. The results of this study generally support small but significant Directional for listeners with severe Hearing loss benefit in a difficult listening environment both with and without the presence of visual information.SumarioEl objetivo de esta investigacion fue exami...
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Directional Hearing aids: then and now.
Journal of Rehabilitation Research and Development, 2020Co-Authors: Todd A. RickettsAbstract:Directional microphone Hearing aids can lead to improved speech recognition when speech and noise are coming from different directions. This technology provides limited benefits, however, and in specific instances use of a Directional Hearing aid mode can be detrimental. This article discusses the benefits and limitations of Directional amplification, summarizes some current work in Directional amplification, and recommends clinical application relative to the use of Directional amplification.
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Directional Hearing aids
Trends in Amplification, 2001Co-Authors: Todd A. RickettsAbstract:A miniature Hearing aid unit to be fitted to and carried on a person's head; there being a Directional microphone in the housing which has front and rear sound admitting openings to respectively supply sounds to the fore and aft ports of the Directional microphone; the rear opening in the Hearing aid housing being located significantly closer to the inner side of the housing than the forward opening so that the alignment between front and rear openings is at an oblique angle of approximately 20° relative to the frontal direction.
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impact of compression and Hearing aid style on Directional Hearing aid benefit and performance
Ear and Hearing, 2001Co-Authors: Todd A. Ricketts, George A Lindley, Paula HenryAbstract:ObjectiveTo evaluate the impact of low-threshold compression and Hearing aid style (in-the-ear [ITE] versus behind-the-ear [BTE]) on the Directional benefit and performance of commercially available Directional Hearing aids.DesignForty-seven adult listeners with mild-to-moderate sensorineural hearin
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predicting Directional Hearing aid benefit for individual listeners
Journal of The American Academy of Audiology, 2000Co-Authors: Todd A. Ricketts, H G MuellerAbstract:: The fitting of Directional microphone Hearing aids is becoming increasingly more routine, and this fitting option has proven to be a successful method to improve speech intelligibility in many noisy listening environments. Data suggest, however, that some Hearing-impaired listeners receive significantly more Directional benefit than others. It is of interest, therefore, to determine if Directional benefit is predictable from identifiable audiologic factors. In this report, we examined whether the slope of audiometric configuration, amount of high-frequency Hearing loss, and/or the aided omniDirectional performance for a speech-in-noise intelligibility task could be used to predict the magnitude of Directional Hearing aid benefit. Overall results obtained from three separate investigations revealed no significant correlation between the slope of audiometric configuration or amount of high-frequency Hearing loss and the benefit obtained from Directional microphone Hearing instruments. Although there was a significant, negative relationship between aided omniDirectional performance and the Directional benefit obtained in one study, there was considerable variability among individual participants, and nearly all of the listeners with the best omniDirectional Hearing aid performance still received significant additional benefit from Directional amplification. These results suggest that audiologists should consider the use of Directional amplification for patients regardless of audiogram slope, high-frequency Hearing loss, or omniDirectional speech intelligibility score.
W.a. Serdijn - One of the best experts on this subject based on the ideXlab platform.
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A dynamic-translinear fully-integrated highly-Directional Hearing aid adapter
2000 IEEE International Symposium on Circuits and Systems (ISCAS), 2000Co-Authors: D. Rocha, W.a. SerdijnAbstract:A Directional Hearing aid adapter was designed and implemented using dynamic translinear (DTL) circuit techniques. The signal-processing core was optimized to yield minimum current consumption for the specified dynamic range. In this paper the design and implementation of the core is presented. It consumes a current of 40 /spl mu/A at a supply voltage of down to 1.0 V having a total integrated capacitance of 400 pF for a dynamic range of 50 dB.
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ISCAS - A dynamic-translinear fully-integrated highly-Directional Hearing aid adapter
2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353), 2000Co-Authors: D. Rocha, W.a. SerdijnAbstract:A Directional Hearing aid adapter was designed and implemented using dynamic translinear (DTL) circuit techniques. The signal-processing core was optimized to yield minimum current consumption for the specified dynamic range. In this paper the design and implementation of the core is presented. It consumes a current of 40 /spl mu/A at a supply voltage of down to 1.0 V having a total integrated capacitance of 400 pF for a dynamic range of 50 dB.
Heiner Römer - One of the best experts on this subject based on the ideXlab platform.
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Directional Hearing in insects with internally coupled ears
Biological Cybernetics, 2016Co-Authors: Heiner Römer, Arne K. D. SchmidtAbstract:Compared to all other Hearing animals, insects are the smallest ones, both in absolute terms and in relation to the wavelength of most biologically relevant sounds. The ears of insects can be located at almost any possible body part, such as wings, legs, mouthparts, thorax or abdomen. The interaural distances are generally so small that cues for Directional Hearing such as interaural time and intensity differences (IITs and IIDs) are also incredibly small, so that the small body size should be a strong constraint for Directional Hearing. Yet, when tested in behavioral essays for the precision of sound source localization, some species demonstrate hyperacuity in Directional Hearing and can track a sound source deviating from the midline by only $$1^{\circ }$$ 1 ∘ – $$2^{\circ }$$ 2 ∘ . They can do so by using internally coupled ears, where sound pressure can act on both sides of a tympanic membrane. Here we describe their varying anatomy and mode of operation for some insect groups, with a special focus on crickets, exhibiting probably one of the most sophisticated of all internally coupled ears in the animal kingdom.
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Directional Hearing in insects with internally coupled ears.
Biological cybernetics, 2015Co-Authors: Heiner Römer, Arne K. D. SchmidtAbstract:Compared to all other Hearing animals, insects are the smallest ones, both in absolute terms and in relation to the wavelength of most biologically relevant sounds. The ears of insects can be located at almost any possible body part, such as wings, legs, mouthparts, thorax or abdomen. The interaural distances are generally so small that cues for Directional Hearing such as interaural time and intensity differences (IITs and IIDs) are also incredibly small, so that the small body size should be a strong constraint for Directional Hearing. Yet, when tested in behavioral essays for the precision of sound source localization, some species demonstrate hyperacuity in Directional Hearing and can track a sound source deviating from the midline by only [Formula: see text]-[Formula: see text]. They can do so by using internally coupled ears, where sound pressure can act on both sides of a tympanic membrane. Here we describe their varying anatomy and mode of operation for some insect groups, with a special focus on crickets, exhibiting probably one of the most sophisticated of all internally coupled ears in the animal kingdom.
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Directional Hearing: from biophysical binaural cues to Directional Hearing outdoors
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2014Co-Authors: Heiner RömerAbstract:When insects communicate by sound, or use acoustic cues to escape predators or detect prey or hosts they have to localize the sound in most cases, to perform adaptive behavioral responses. In the case of particle velocity receivers such as the antennae of mosquitoes, Directionality is no problem because such receivers are inherently Directional. Insects equipped with bilateral pairs of tympanate ears could principally make use of binaural cues for sound localization, like all other animals with two ears. However, their small size is a major problem to create sufficiently large binaural cues, with respect to both interaural time differences (ITDs, because interaural distances are so small), but also with respect to interaural intensity differences (IIDs), since the ratio of body size to the wavelength of sound is rather unfavorable for diffractive effects. In my review, I will only shortly cover these biophysical aspects of Directional Hearing. Instead, I will focus on aspects of Directional Hearing which received relatively little attention previously, the evolution of a pressure difference receiver, 3D-Hearing, Directional Hearing outdoors, and Directional Hearing for auditory scene analysis.
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Out of phase: relevance of the medial septum for Directional Hearing and phonotaxis in the natural habitat of field crickets
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2013Co-Authors: Stefan Hirtenlehner, Heiner Römer, Arne K. D. SchmidtAbstract:A modified tracheal system is the anatomical basis for a pressure difference receiver in field crickets, where sound has access to the inner and outer side of the tympanum of the ear in the forelegs. A thin septum in the midline of a connecting trachea coupling both ears is regarded to be important in producing frequency-dependent interaural intensity differences (IIDs) for sound localization. However, the fundamental role of the septum in Directional Hearing has recently been challenged by the finding that the localization ability is ensured even with a perforated septum, at least under controlled laboratory conditions. Here, we investigated the influence of the medial septum on phonotaxis of female Gryllus bimaculatus under natural conditions. Surprisingly, even with a perforated septum, females reliably tracked a male calling song in the field. Although reduced by 5.2 dB, IIDs still averaged at 7.9 dB and provided a reliable proximate basis for the observed behavioural performance of operated females in the field. In contrast, in the closely related species Gryllus campestris the same septum perforation caused a dramatic decline in IIDs over all frequencies tested. We discuss this discrepancy with respect to a difference in the phenotype of their tracheal systems.
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sound transmission and Directional Hearing in field crickets neurophysiological studies outdoors
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2010Co-Authors: Konstantinos Kostarakos, Heiner RömerAbstract:Many studies provide detailed behavioural and neurophysiological information on the ability of crickets to localize a sound source under ideal acoustic conditions, but very little is known about how they perform in real habitats. We investigated Directional Hearing of crickets in the field using a neurophysiological approach, by recording the activity of the two prominent, bilaterally homologous AN1 neurons simultaneously in a cricket’s habitat. The discharge and latency differences of the pair of neurons in response to conspecific chirps presented at different distances and directions were taken as a measure of Directional information. The maximum Hearing distance differed between individuals and weather conditions from 1 to 15 m (mean 9.2 m). Although the AN1 activity generally decreased with increasing distance, large fluctuations in the magnitude of responses occurred with distance, indicating that the intensity gradient over distance is often irregular. The Directional information provided in the discharge differences of the two neurons also varied with distance. Again, there was no simple Directional gradient on the transmission channel; rather, with decreasing distance to the source there were receiver locations providing suprathreshold responses, but no Directional information. The consequences for the ability of field crickets to communicate acoustically close to the ground are discussed.