bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosis and monitoring of pulmonary fibrosis using ultrasound multiple scattering, an in vivo rodent study
Authors: Mohanty Kaustav , Blackwell John , Ali Mir H. , Egan Thomas , Muller Marie M.
Published: April 2019

Idiopathic pulmonary fibrosis (IPF) affects 200,000 patients in the U.S. IPF is responsible for changes in the micro-architecture of the parenchyma, such as thickening of the alveolar walls, which reduces compliance and elasticity. In this study, it is proposed to verify the hypothesis that changes in the micro-architecture of the lung parenchyma can be characterized by exploiting multiple scattering of the ultrasound waves by the lung parenchyma. Ultrasound propagation in a highly scattering regime follows a diffusion process, which can be characterized using the Diffusion Constant. We hypothesize that in a fibrotic lung, the thickening of the alveolar wall reduces the amount of air (compared to a healthy lung), thereby minimizing the scattering events. Pulmonary fibrosis is created in Sprague-Dawley rats by instilling bleomycin into the airway. The rats are studied in groups of n = 6 (3 male and 3 female) 2, 3, and 4 weeks after bleomycin administration. This allowed us to provide a range of severity of pulmonary fibrosis for assessment. Using a 128-element linear array transducer operating at 7.8 MHz, in vivo experimental data are obtained from Sprague-Dawley rats, and the Diffusion Constant is calculated. Right after the ultrasound measurement, the rats are euthanized, and computed tomography scans are performed to validate the degree of fibrosis created. Significant differences (p < 0.05) in the D values between control and fibrotic rats showcase the potential of this parameter for diagnosis and monitoring of IPF.
Comparison of ocular biomechanical properties in normal and glaucomatous eyes using ultrasound surface wave elastography
Authors: Sit Arthur J. , Kazemi Arash , Zhou Boran , Zhang Xiaoming
Published: April 2019

Biomechanical properties of the eye are important in understanding glaucoma. However, specific tissues that may be affected are unclear. In this study, we compared glaucomatous and normal eyes for differences in corneal tissue elasticity (as indicated by wave speed) and global ocular rigidity. Both eyes of 10 glaucoma patients and 10 normal controls, matched for age and intraocular pressure (IOP), were included. The ocular rigidity coefficient was calculated from supine IOP measured with and without a 10 g weight added to the tonometer. The wave speed in the cornea was measured by ultrasound surface wave elastography. With this technique, a spherical-tipped probe (4 mm diameter) was placed on the closed eyelid and vibrated at 100 Hz for 0.1 s. The wave speed was calculated using the phase gradient method. Measurements for normal and glaucoma eyes were compared using generalized estimating equation models. The corneal wave speed was similar between normal and glaucomatous eyes (P = 0.4). However, ocular rigidity was significantly lower in glaucomatous eyes (P < 0.001) compared with normal eyes. There was no difference in age or IOP (P > 0.3). Lower ocular rigidity in glaucomatous eyes suggests that a more compliant ocular shell may predispose to glaucoma. However, the lack of difference in the corneal wave speed suggests that corneal tissue is not significantly affected, and changes likely involve the sclera.
Acoustic vehicle alerts and sleep disruption: A content analysis of online complaints and inquiries
Authors: Botta Jeanine
Published: April 2019

Research on the effects of traffic noise on sleep focuses on sounds created by vehicles that are traveling, whether in continuous motion on a highway or road or temporarily slowed on a congested street. Most acoustic vehicle alerts are introduced without consideration for their potential to disrupt sleep or affect quality of life. Panic alarm, marketed as a safety feature and standard with most cars, was accepted by regulatory and consumer protection agencies without question or concern for its necessity or its potential to create new noise. Criticism about car alarms, remote lock signals that use horn sounds, panic alarm, and backup beeping in passenger cars is common in everyday discourse but rare within the public health sphere. This study will use content analysis of online complaints posted in public databases, discussion forums, and car owner forums to explore common experiences related to sleep disruption. Focus will be on technologies not used while driving and will not include pedestrian alerts or backup beeping used by commercial or industrial vehicles. The study will include posts by those whose sleep has been affected and by car owners inquiring about methods of turning off a sound source out of concern for a neighbor.
How to design vehicle alert signals?
Authors: Genuit Klaus
Published: April 2019

E-Mobility becomes more and more popular. At the same time, acoustical alert signals are requested by law. This is in conflict with less traffic noise and better environmental sound. Especially, the request that the alert signals should contain tones, and these tones should have a frequency shift in the dependency of speed can create disharmonic sounds, e.g., if more than one vehicle is present. This will be a negative impact on the soundscape, and the annoyance will increase. Different concepts of alert signals will be discussed with respect to detectability, localization, and sound quality.
Upgrading backup alarms to reduce encroachment on soundscapes in Denali National Park
Authors: Betchkal Davyd , Fristrup Kurt M.
Published: April 2019

Denali maintains a sizeable fleet of maintenance vehicles that are equipped with backup alarms. Across many years, park acoustical monitoring demonstrated that tonal backup alarms were audible at one to two miles distance from the hazard zone immediately behind the truck. Following a successful demonstration of backup alarms with broadband signals, 77 vehicles at Denali were upgraded. The aggregate cost of the devices was just under $11,000, and the Denali auto shop provided 25 h of staff time for the upgrade. CadnaA modeling was used to compare the park area in which the old and new alarms were audible, assuming that both broadcast the same level (107 dB, A-weighted). The broadband alarm was predicted to be audible in 2.9 km2, compared with 6.9 km2 for the tonal alarm. The adaptive level feature of the new alarms yielded additional benefits in quiet locales. After the upgrade, backup alarm noise became noticeably less along the Denali Road corridor, and these improvements motivated the park to incorporate language regarding backup alarms into construction contracts.
Regarding sources of irreducible variation in transformed up-down staircase experiments
Authors: Christian Andrew
Published: April 2019

A modicum of variation in the result is always expected when a psychoacoustic experiment is run multiple times on a single subject. Historically, this variation was attributed to human shortcomings: lapses in attention, inexperience, and the effects of memory, learning, and fatigue. It is demonstrated that the use of any psychophysical method that requires a binary response (i.e., a correct or incorrect response) will generate irreducible variation in the result—even for a "perfect" subject. At NASA, a recent battery of low-frequency simultaneous masking experiments was undertaken (see NASA-TM-2018-220120). This effort was preceded by a lengthy test design phase—also documented therein—during which it was determined that the test should consist of a large number of subjects, each to be tested minimally. For this, transformed up-down staircases were simulated in order to produce a prediction of the irreducible variance as a function of the staircases’ parameters (e.g., length in the number of trials). The results from repeated test conditions taken during the experiment indicate that at least half of the variation observed within subjects may be coming from this irreducible source, though the propensity to produce inconsistent results may be a feature of some subjects more than others.
Design and fabrication of a linear broadband non-reciprocal acoustic waveguide using feedforward control
Authors: Geib Nate , Sasmal Aritra , Grosh Karl , Popa Bogdan Ioan , Zhai Yuxin
Published: April 2019

Acoustic metamaterials that exhibit non-reciprocal transmission have received substantial attention due to their wide range of applications such as noise control, diagnostic imaging, communications, and acoustic cloaking. Passive metamaterials achieve non-reciprocity through system resonances combined with nonlinearities or manipulation of phononic bandgap and are usually effective over a narrow band of frequencies. In this study, we describe the development of a new class of acoustic waveguides that exhibit linear non-reciprocal sound transmission over a wide range of frequencies. We use an open loop feedforward control mechanism where the measured local pressure is passed through an electronic controller and transmitted downstream to actuate an acoustic source. Analysis of the idealized one-dimensional model with a continuous distribution of probes and sources shows spatial asymmetry with attenuation in one direction and amplification in the other for frequencies ranging from one-half to five times the ratio of the active length of the segment to the acoustic wavelength. We show that such behavior can be replicated in a physical system with a finite array of acoustic probes and sources and develop the framework to compute the stability of this class of active waveguides. The experimental results for a simple feedforward model system are presented.
Non-reciprocity in mechanically modulated elastic metamaterials with geometric asymmetry
Authors: Goldsberry Benjamin M. , Wallen Samuel P. , Haberman Michael R.
Published: April 2019

Elastic metamaterials with time- and space-dependent effective material properties have received great attention as a means to generate non-reciprocal wave propagation in acoustic and elastic media. These materials have promise for applications such as acoustic communication devices with increased data throughput and improved vibration isolation components. One means to modulate the material properties of a heterogeneous medium is via nonlinear mechanical deformation on time scales that are slow compared to propagating waves. This approach has been explored by the authors using the finite element method (FEM) to demonstrate non-reciprocal elastic wave propagation in negative stiffness honeycombs with a time- and space-varying external pre-strain [Goldsberry et al., JASA 144, 1763 (2018)]. One benefit of FEM is that it can be used to study the degree of non-reciprocity when varying sub-wavelength geometry or geometric modulations that are difficult or impossible to represent using analytical models. The present work employs FEM to investigate non-reciprocity in elastic lattices consisting of unit cells with varied geometric asymmetry and more general forms of mechanical modulation. [Work supported by National Science Foundation EFRI under Award No. 1641078.]
Simulated cochlear-implant processing results in major loss of acoustic information regarding differences in talkers’ voice qualities
Authors: Arjmandi Meisam K. , Ghasemzadeh Hamzeh , Dilley Laura
Published: April 2019

The ability to recognize different voice qualities is essential for good talker identification; yet, little is known about how well voice quality cues of talkers are transmitted through the degraded speech signals delivered by cochlear implants (CIs). This study examined how CI speech filtering affects acoustic distinctiveness of individuals with and without voice disorder. Sustained /a/ vowels uttered by speakers with normal or disordered voice were processed using 4, 8, 12, 16, 22, and 32 channel noise-vocoders. The effect of CI processing on the distinctiveness of talkers with normal and disordered voices was measured using the Mahalanobis distance measure on Mel-frequency cepstral coefficients derived from samples across these groups. The analysis confirmed that CI vocoding dramatically degrades acoustic cues in frequency sub-bands that signal abnormal voicing behavior. Remarkable spectral degradation was observed in low- (<2 kHz), mid- (~4-12 kHz), and high-frequency (>12 kHz) bands for simulated conditions compared with unprocessed signals. These findings indicate that CI users likely have almost no ability to distinguish talkers differing in voice qualities. These results highlight challenges that CI users face for recognizing talkers differing in voice quality, due to these users’ lack of access to fine-grained spectro-temporal details in voices.
How task effects and reading ability relate to talker processing
Authors: Abu El Adas Sandy , Levi Susannah V.
Published: April 2019

Studies show that listeners are better at processing talker information in their native language compared to an unfamiliar language. Several studies have explored two possible sources of this effect by manipulating lexical-semantic information on the one hand and phonological familiarity on the other. To probe these two types of information, researchers have manipulated the stimuli (e.g., phonologically similar or different languages, nonwords) and the listeners (e.g., listeners with reading impairments because reading ability is linked to phonological processing). These prior studies have found that individuals with poorer phonological processing also have poorer talker processing. However, it is unclear whether these individuals show poor performance in talker processing due to task demands related to creating talker representations in long-term memory. To test the question of task effects, we compare performance of individuals with a range of reading abilities on two tasks of talker processing: a discrimination task and an identification task. In addition, to control for both the lexical and phonological properties of the stimuli, stimuli were either words or nonwords and had either high or low phonotactic probability. Our preliminary results suggest that the effect of reading on talker processing depends on the type of task.
Talker variability, auditory attention, and speech processing efficiency
Authors: Perrachione Tyler K.
Published: April 2019

A classic finding in speech perception is that speech is processed more efficiently from a single, continuous talker than from mixed talkers. Given enormous variation in the acoustic realization of speech, it is thought that talker adaptation is necessary to ascertain the mappings between talkers’ speech acoustics and listeners’ abstract phonological representations. However, a suite of empirical studies from our laboratory may suggest a predominately attention-based explanation for effects attributed to talker adaptation: using behavioral experiments, neuroimaging, and noninvasive brain stimulation, we have probed how speech processing efficiency under talker variability is affected by temporal, phonological, contextual, and expectational factors. We find that processing benefits from talker continuity are automatic and feedforward, depending on temporal continuity in the source of speech but not the amount of talker-specific phonetic detail or listeners’ expectations about source continuity. Correspondingly, processing costs from talker discontinuity occur even when phonetic contrasts are unambiguous across talkers but are insensitive to the magnitude of phonetic variability, amount of preceding exposure to a talker, or top-down expectation about discontinuity. We consider how domain-general models of attention and auditory streaming may parsimoniously account for these differences in the speech processing efficiency between single and mixed talkers.
Broad bandwidth acoustic backscattering from small fish : Measurements and cylindrical model
Authors: Manik Henry M.
Published: April 2019

Acoustic backscattering measurements were conducted of individual ray-finned fishes (Gnathopogon caerulescens) at frequencies from 30 to 150 kHz in an acoustic tank laboratory. Acoustic backscatter measurements for dead ray-finned fishes were made versus incidence angle from -30 deg to 30 deg relative to lateral aspect directions. Backscatter spectra from whole fish vary with the fish length and shift to lower frequencies at higher pitching angles. The backscatter spectra from pitching angle differ in both amplitude and positions. A cylindrical model of fish backscatter was developed and compared with the acoustic measurements.
Scattering of focused beams by spheres: Understanding the high-frequency angular structure
Authors: Daniel Timothy D. , Marston Philip L.
Published: April 2019

Previous work on scattering of Bessel beams by spheres [P. L. Marston, J. Acoust. Soc. Am. 122, 247–252 (2007)] and recent work expanding linear focused beams in terms of a Bessel beam superposition [T. D. Daniel et al., J. Acoust. Soc. Am. 144, 3076–3083 (2018)] provide a framework for exploring the scattering of focused beams by spheres. In analogy with the work done on the scattering of Gaussian beams by spheres [P. L. Marston, J. Acoust. Soc. Am. 129, 1773–1782 (2011)], the angular scattering pattern of a sphere in a focused beam is calculated from a partial wave series with appropriate weighting factors (also known as beam shape coefficients). The high-frequency pattern for rigid spheres is found to have distinctive shadow boundaries in both the forward and backward scattering hemispheres. The sphere is centered on the beam axis. A physical optics model of the scattering reproduces the location and general shape of the shadow boundaries in both scattering hemispheres, confirming the calculated beam shape coefficients for a spherical cap focused source. [Work supported by ONR.]
Verification and validation of a coupled elasto-acoustic-damage system
Authors: Pitt Jonathan
Published: April 2019

A novel time-domain method for simulating dynamic damage evolution in a coupled structural-acoustic system is presented, with the aim of first principles modeling of acoustic emissions from failure. The system is derived via the theory of continuum damage mechanics and incorporates standard damage evolution models. The overall solution method is staggered, first solving for the dynamic damage evolution with an explicit step, and then using the new values of damage in the coupled computation of the structural-acoustic system. The spatial domain is discretized using a mixed finite element method, and the temporal domain is discretized with a higher-order implicit time discretization scheme. Code and solution verification of the fully coupled solution algorithm are presented, as are validation studies for cases with and without evolving damage. Applications with evolving damage and presents a methodology to study changes in the structural acoustic response from dynamically evolving damage in the structure are presented. Examples of downstream usage of the evolving structural response are discussed in the concluding remarks.
Acoustical design for libraries in schools to comply with ANSI S12.60
Authors: Brooks Bennett M.
Published: April 2019

In K-12 schools, the library functional space is now usually called the media center, as this space houses and disseminates information that is stored on both print and digital media. These spaces have fewer sound absorbent book stacks than were found in previous print-only libraries. Instead, computer workstations for student access to local and web-based material are provided. Often these facilities are used as group learning spaces, with several group classes occurring simultaneously. These changes to the traditional school library space present challenges to the acoustical design. Another challenge is that in a number of school districts across the US, a media center must be designed to meet the requirements of ANSI/ASA 12.60-2010/Part 1, “American National Standard Acoustical Performance Criteria, Design Requirements and Guidelines for Schools, Part 1: Permanent Schools,” also known as the “Classroom acoustics standard.” This is because a media center can be defined as a core learning space that is subject to that standard, with its requirements for low noise and reverberation, and for higher sound isolation from adjacent spaces. Several case studies are presented which highlight the design challenges for modern school media centers, and the successful design solutions.
A church space that could be a library, media room, meeting room, performance space, or dining room—or with proper room acoustic modifications—An effective sound reinforcement system including audio recording, and suitable video recording and projection it could function as all of the above noted spaces
Authors: Coffeen Robert C.
Published: April 2019

In a nearby church that was recently visited a space was viewed that is nicely appointed from an aesthetic viewpoint but primarily due to room acoustics, noise issues, and lack of proper sound and video systems, it did not seem to adequately serve any of the functions noted by the title of this presentation. The church is considering a renovation of this space. This presentation will describe how the space can serve all of the noted functions with relatively simple and easy to operate acoustic, sound system, and video modifications without significantly disturbing its current and desirable appearance.
Emission baffle deformations in bat biosonar and biomimetic systems
Authors: Zhang Liujun , Yang Luhui , Müller Rolf
Published: April 2019

Old-World leaf-nosed bats (Hipposideridae) and horseshoe bats (Rhinolophidae) are two families of echolocating bats that emit their biosonar pulses through nostrils which are surrounded by elaborated baffle shapes (“noseleaves” ). Prior work has shown that the noseleaves change shape in synchrony with ultrasound emission. These deformations involve at least two noseleaf parts with static (geometric) as well as dynamic complexity. To investigate how these deformations could be used in bioinspired systems, data has been collected from bats recorded with microphone/camera arrays as well as a biomimetic sonar head with a biomimetic noseleaf model inspired by Pratt's roundleaf bats (Hipposideros pratti). Both sets of experiments have produced qualitatively similar results that show an emitted wave field which depends on frequency, direction, and also time. Furthermore, the results obtained with the biomimetic noseleaf have demonstrated that noseleaf deformations during ultrasound emission can result in an enhanced information-encoding capacity. Current work is aimed at establishing whether this enhanced coding capacity can be utilized to improve performance, especially in sensing tasks that are related to the natural environments in which the bats' biosonar systems operate. It also needs to be established how much detail needs to be mimicked in an engineered system to harness these effects.
Reducing bats' pinnae deformation complexity for a biomimetic reception baffle dynamics
Authors: Guo Jia , Kurdila Andrew , Müller Rolf
Published: April 2019

Horseshoe bats are known to have about 20 muscles on each pinna that allow the animals to deform their pinnae during echo reception. Simplified biomimetic reproductions of this reception baffle dynamics have demonstrated the encoding of additional, useful sensory information. However, reproducing the full complexity in the actuation of the bat pinna shapes by virtue of numerous muscles poses a daunting challenge. Furthermore, it remains unknown which level of complexity is necessary to realize the functional advantages of the bats' pinna dynamics. To address this issue, the current work has focused on non-rigid deformations of the pinnae. 3D kinematic data for a dense grid of landmark points distributed over the pinna surface has been used as input for manifold learning algorithms designed to reduce the dimensionality of the motion. The results of this analysis suggest that the deformations of the pinna can be described in spaces that with much lower dimensionality than the original kinematic data. In addition, a kernel method has been implemented to generate a reduced model of the pinna deformations. Ongoing work is aimed at understanding how these low-dimensional descriptions of the pinna deformation relate to muscular coordination patterns in the pinna and its dynamic functional characteristics.
Coordination of sonar emitter and receiver dynamics inspired by bats
Authors: Zhang Shuxin , Liu Yanming , Müller Rolf
Published: April 2019

Recent biomimetic sonar systems have started to mimic the mobility seen in the emission and reception baffles of bats (i.e., “noseleaves” and pinnae) in greater detail. Some of these efforts have included rigid rotations as well as non-rigid shape changes. Since some bat species are known to actuate their noseleaves during pulse emission and their two pinnae during pulse reception, it may be hypothesized that coordination between the dynamic behaviors of these baffle structures is important to system-level biosonar performance. However, it remains to be determined how the complicated rigid and non-rigid changes to the noseleaves and pinnae of bats are coordinated in the animals' biosonar behaviors. To shed some light on this dynamic system integration in bat biosonar, we have conducted experiments with a species of hipposiderid bat (Pratt's roundleaf bat, Hipposideros pratti) where at least 24 landmark points have been placed on the noseleaf and both pinnae in order to track the non-rigid shape changes in all these three structures simultaneously. A canonical correlation analysis has confirmed that the motions of the noseleaf and both pinnae are highly correlated with each other. Work to identify the nature of these relationships using techniques from nonlinear dynamics is currently underway.
Pulse-train time structure for dynamic biomimetic sonar
Authors: Liu Yanming , Zhang Shuxin , Müller Rolf
Published: April 2019

The biosonar pulse trains of echolocating bats can have pronounced time patterns. A well-known example are adaptive increases in pulse repetition rates seen when certain bat species approach their prey. Furthermore, the production of pulse groups has been reported to create pulse-timing diversity outside of prey pursuit in several bat species. In order to replicate the biosonar capabilities of bats, a biomimetic sonar system may have to integrate this level of adaptivity. If the system also mimics the peripheral dynamics, i.e., shape deformations of the noseleaves and pinnae, in species such as the horseshoe bats, the question arises how the pulse timings and the shape deformations should be best coordinated. To investigate this issue, synchronized recordings of noseleaf motion and pulse emission patterns have been obtained from hipposiderid bats. The noseleaf deformations have been characterized (clustered) based on reconstructed trajectories of five landmark points. Similarly, the corresponding biosonar pulse trains were classified based on similarity metrics developed for neural spike trains and are based on cost assigned to that operations that are needed to be performed to transform one spike pattern into another. The relationships between distances in the noseleaf motion and pulse-train domains are the subject of ongoing research.
Motion-resistant vascular ultrasound imaging based on real-time eigen-filtering
Authors: Chee Adrian J. , Yiu Billy Y. , Yu Alfred C.
Published: April 2019

Doppler flow imaging has become a standard clinical modality for vascular diagnostics. Nevertheless, it remains challenging to perform vascular ultrasound in more complicated diagnostic scenarios, because significant flashing artifacts may appear due to inadequate suppression of Doppler clutter arising from moving tissues. For one decade, we have been striving to achieve motion-resistant vascular ultrasound by designing advanced eigen-filtering algorithms whose attenuation response is adapted to clutter characteristics. Using a receiver operating characteristics analysis approach, we showed that in the presence of vessel pulsation and tissue vibration, our eigen-based motion-resistant signal processing chain yielded a significantly higher true positive rate (>90%) in depicting flow in comparison to non-adaptive signal processing chains. Another engineering challenge that we have overcome is the high computational demand of eigen-processing algorithms. We have successfully devised real-time implementations of eigen-based motion-resistant signal processing through designing parallel computing kernels that are executed on a graphical processing unit (GTX Titan X). In particular, we achieved real-time video-range throughput for full-view Doppler frames, up to a scan depth of 5 cm for slow-time ensemble length of 16 samples (i.e., beyond the typical requirement for carotid scans). These findings serve well to substantiate the practical feasibility of performing motion-resistant vascular ultrasound.
Graduate studies in Acoustical Oceanography in the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution Joint Program
Authors: Lavery Andone C.
Published: April 2019

An overview of graduate studies in Acoustical Oceanography within the framework of the Massachusetts Institute of Technology (MIT) and Woods Hole Oceanographic Institution (WHOI) Joint Program is presented, including a brief history of the program, facilities, details of the courses offered, alumni placing, funding opportunities, and current program status, faculty members and research. Emphasis is given to the key role of the joint strengths provided by MIT and WHOI, the strong sea-going history of the program, and the potential for highly interdisciplinary research.
Opportunities for graduate studies in acoustics within the College of Engineering at the University of Nebraska–Lincoln
Authors: Wang Lily M. , Ryherd Erica E. , Turner Joseph A. , Zhu Jinying
Published: April 2019

A number of faculty in the College of Engineering at the University of Nebraska–Lincoln (UNL) conduct research in acoustics and mentor graduate students. Within the Durham School of Architectural Engineering and Construction, based at UNL’s Scott Campus in Omaha, Lily Wang and Erica Ryherd are active in architectural acoustics and noise (http://nebraskaacousticsgroup.org ). In Civil Engineering, Jinying Zhu (also based on UNL’s Scott Campus in Omaha) focuses in structural acoustics, using ultrasonic waves for concrete evaluation. In Mechanical and Materials Engineering, Joseph Turner (based at UNL’s City Campus in Lincoln) studies ultrasound propagation through complex media for quantitative characterization of materials/microstructure (http://quisp.unl.edu ). UNL is additionally home to an active student chapter of the Acoustical Society of America, the first to be founded in 2004. This poster will summarize the graduate-level acoustics courses and lab facilities at UNL within the College of Engineering, as well as the research interests and achievements of our faculty, graduates, and students.
Pursuing graduate degrees in acoustics at Penn State
Authors: Sparrow Victor , Russell Daniel A.
Published: April 2019

The Graduate Program in Acoustics at Penn State is the only program in the U.S. offering the Ph.D. in Acoustics as well as M.S. and M.Eng. degrees in Acoustics. An interdisciplinary program with faculty from a variety of academic disciplines, the Graduate Program in Acoustics is administratively aligned with the College of Engineering and closely affiliates with the Applied Research Laboratory. Research areas include: structural acoustics, nonlinear acoustics, architectural acoustics, signal processing, aeroacoustics, biomedical ultrasound, transducers, computational acoustics, noise and vibration control, psychoacoustics, and underwater acoustics. Course offerings include fundamentals of acoustics and vibration, electroacoustic transducers, signal processing, acoustics in fluid media, sound and structure interaction, digital signal processing, experimental techniques, acoustic measurements and data analysis, ocean acoustics, architectural acoustics, noise control engineering, nonlinear acoustics, outdoor sound propagation, computational acoustics, biomedical ultrasound, flow induced noise, spatial sound and three-dimensional audio, acoustics of musical instruments. More than 700 Penn State Acoustics graduates serve widely throughout military and government labs, academic institutions, consulting firms and industry. This poster describes faculty research areas, laboratory facilities, student demographics, successful graduates, and recent enrollment and employment trends.
Underwater acoustics and ocean engineering at the University of Rhode Island
Authors: Van Uffelen Lora J. , Miller James H , Potty Gopu R.
Published: April 2019

Underwater acoustics is one of the primary areas of emphasis in the Ocean Engineering Department at the University of Rhode Island, the first Ocean Engineering program in the United States. The program offers Bachelors, Masters (thesis and non-thesis options) and Ph.D. degrees in Ocean Engineering. These programs are based at the Narragansett Bay campus, providing access to a living laboratory for student learning. Some key facilities of the program are an acoustics tank, a 100-foot-long wave tank, and currently the R/V Endeavor, a UNOLS oceanographic research vessel operated by the University of Rhode Island. A new Regional Class vessel is anticipated in 2021. At the graduate level, students are actively involved in research focused in areas such as acoustical oceanography, propagation modeling, acoustic positioning and navigation, geoacoustic inversion, marine mammal acoustics, ocean acoustic instrumentation, and transducers. An overview of classroom learning and ongoing research will be provided, along with information regarding the requirements of entry into the program.
A Spatially Distributed Vibrotactile Actuator Array (SDVAA) for music-to-vibrotactile sensory augmentation
Authors: Berdahl Edgar J. , Franklin Austin , Sheffield Eric
Published: April 2019

The design of a Spatially Distributed Vibrotactile Actuator Array (SDVAA) is presented. It employs a multitude of vibrotactile actuators in order to communicate a larger amount of information than is possible using a single actuator. The SDVAA is currently being used for applications in music-to-vibrotactile sensory augmentation. While prior related projects have focused more on sensory substitution, this project aims only to add to a person’s experience by augmenting a multimedia presentation with vibrotactile feedback. Because haptic perception is fundamentally different than auditory perception, it makes sense to rearrange the information transmitted to the haptic senses. For example, while auditory perception is limited to approximately the range 20 Hz to 20 kHz, tactile perception is limited primarily to the range 0 Hz to 800 Hz (if not higher). Accordingly, one approach being considered for converting auditory signals to vibrotactile signals is pitch shifting. Project results relating to music composed specifically for the SDVAA as well as general musical vibrotactile prototyping concepts will be presented.
Heavy-weight impact testing: Test repeatability for a modified kettlebell and comparison of impact source weights and drop heights
Authors: Raley Michael
Published: April 2019

Noise and vibration from heavy-weight impacts associated with fitness activities are a common source of complaints in hotels, multi-family residences, and corporate office spaces. In situ testing using various heavy/hard impact sources is commonly used to evaluate the effectiveness of mitigation measures to address noise and vibration complaints. Previous work (LoVerde et al., Internoise 2015) proposed the use of a 16-lb spherical shot for in situ testing. However, significantly heavier weights are common in many gyms. For instance, hotel chains commonly include free-weights with a range of 5 to 75 lb in their fitness rooms. It is not known if the relatively light 16-lb shot provides results that are indicative of impacts from significantly heavier weights. This presentation evaluates the use of heavier (50-lb and 100-lb) kettlebells and varying drop heights as alternates to the 16-lb shot. Additionally, this presentation evaluates test repeatability for the kettlebells which have been modified so that the impact surface is spherical in shape.
Efficacy of high-performance ceiling systems
Authors: Byrick Wilson , Golden Matthew V.
Published: April 2019

A current approach to try to solve a low frequency impact-induced structure-borne noise issue in lightweight woodframe buildings has been the application of a resilient ceiling suspended by one-inch deflection spring hangers. While this system has been lab tested it was only compared to an assembly with no isolation in which the gypsum board was directly attached to the bottom of the joists. The authors have repeated the testing of one-inch deflection ceiling hangers in the same lab but this time they compared it to the same isolators with the springs removed, standard resilient sound clips and other ceiling isolation systems. Relative performance differences of the isolation systems will be presented along with transmissibility, static stiffness, dynamic stiffness and damping measurements of each isolation element. A few theories as to why the systems behave the way they do will also be presented.
Finite difference time domain investigation of interior sound fields generated by parametric acoustic arrays
Authors: Saksena Anpeksh A. , Harne Ryan L.
Published: April 2019

Parametric acoustic arrays enable tight beams of audible sound through the nonlinear collimation and mixing of ultrasonic acoustic waves. Previous investigations have considered parametric array characterization when operated in free field environments and in the presence of rigid planar reflectors, so that the opportunity to leverage parametric arrays in more realistic environments with diffusive scatterers and absorptive surfaces remains unexplored. To fill the knowledge gap, this research establishes a finite difference time domain (FDTD) model of a parametric array in an interior environment with a combination of reflective, absorptive, and diffusive bounding surfaces. The modeling framework builds upon existing FDTD models of nonlinear ultrasound wave propagation used in the life sciences and medicine. Here, the studies seek to elucidate how the sonic sound field is manipulated when the reflective surfaces that receive the nonlinear ultrasonic waves are neither planar nor perfectly reflective. The relative ability to take advantage of such interaction between incident ultrasound and reflected energies, when compared to a perfectly rigid plane for reflection, is examined in detail. All together, this work establishes and harnesses an FDTD modeling framework to examine the use of parametric acoustic arrays in conventional interior environments having reflective, absorptive, and diffusive surfaces.
Born approximation of acoustic radiation force and torque on soft objects of arbitrary shape
Authors: Jerome Thomas S. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: April 2019

When the density and compressibility of an object are similar to the corresponding properties of the surrounding fluid, and the dominant contribution to the acoustic radiation force depends on gradients of the energy densities as occurs in plane standing waves, the Born approximation may be used to calculate both the radiation force and torque. The approximation consists of integrating the monopole and dipole contributions to the force throughout the volume of the object, and thus it is applicable to objects with arbitrary shapes and material property distributions. Here, an axisymmetric object in a plane standing wave is considered, resulting in one-dimensional integral expressions for the radiation force and torque. The integrals are evaluated analytically for homogeneous spheres and cylinders. The accuracy of the approximation is assessed via comparison with full solutions for spheres and prolate spheroids based on eigenfunction expansions for the corresponding scattering problem. Different densities and compressibilities of the object and the surrounding medium, as well as different sizes, shapes, and orientations of the object relative to the standing wave field, are considered. Limitations of the approximation and potential extensions to more complex wave fields are discussed. [T.S.J. supported by the ARL:UT McKinney Fellowship in Acoustics.]
Effect of noise reduction on cortical speech processing in hearing aid users
Authors: Kim Subong , Choi Inyong , Wu Yu-Hsiang
Published: April 2019

Noise reduction (NR) has been widely used in hearing aids (HAs) to increase ease and comfort of listening and to reduce listening effort. However, NR attenuates noise at the potential cost of distorting speech cues. This makes it challenging for audiologists to select the best configuration for NR during HA fitting process. The long-term goal of our research is to optimize HA fitting by characterizing the neural mechanisms underlying the effect of NR. The purpose of the present study is to examine the effect of NR on cortical dynamics during speech-in-noise tasks in HA users using electroencephalography. Our recent study with normal-hearing listeners has shown that speech recognition in low-level noise engaged greater early activity (~300 ms after word onset) in left supramarginal gyrus and weaker late activity (~700 ms) in left inferior frontal gyrus, than in high-level noise. Based on these findings, we hypothesized that, for a given patient, the optimal NR configuration would be the one that can recruit this “low-level noise” pattern of neural activity. Initial results from the electroencephalographic source space analysis will be presented, and underlying cortical mechanisms of speech processing in HA users will be discussed.
Discrimination of rippled spectra: Contribution of excitation-pattern and temporal-processing mechanisms
Authors: Milekhina Olga , Nechaev Dmitry , Supin Alexander
Published: April 2019

Rippled-spectrum signals are used for measurements of signal resolution in hearing-impaired listeners and cochlear-implant users. Two mechanisms may be responsible for rippled-spectrum resolution. The excitation-pattern mechanism determines the ripple density resolution (ripples/oct). The temporal-processing mechanism determines the ripple frequency spacing limit (kHz). Contributions of the mechanisms can be assessed by comparison of resolutions of band-limited rippled spectra with different center frequencies, because the ratio of rippe spacing to ripple density is frequency-proportional. Ripple-density resolutions of half-octave rippled spectra were measured at center frequencies from 0.5 to 4 kHz. The measurements were performed either by discrimination between rippled-spectrum test and reference signals differing by ripple phases or by discrimination between a rippled-spectrum test and non-rippled reference signal. For discrimination between rippled-spectrum test and reference signals, resolution specified in ripples/oct little depended on center frequency, as predicted by the excitation-pattern model. For discrimination between rippled test and non-rippled reference signals, the resolution specified in ripple frequency spacing little depended on center frequency, as predicted by the temporal-processing model. It was concluded that contributions of the excitation-pattern and temporal-processing mechanism depend on the discrimination task.
Decoding listener’s attention :Can it be improved with behavioural measure of selective attention?
Authors: Huet Moïra-Phoebé , Micheyl Christophe , Gaudrain Etienne , Parizet Etienne
Published: April 2019

During the past decade, there has been growing interest in the neural correlates of selective attention to speech. In these studies, listeners were instructed to focus their attention on one of two concurrent speech streams. However, in everyday-life situations, a listener's attention can switch rapidly between different voices. Thus, we have developed a behavioural protocol to infer the dynamics of auditory attention over time. After listening to two simultaneous stories—a target and an interferer—the participants have to find, among a set of words, those present in the target story. The participant’s responses are then used to estimate, retrospectively, when their attention was directed toward the target, or toward the interferer. Neural data, recorded with EEG, and behavioural measures are combined to extract the brain's temporal response function in response to these stimuli. Moreover, to promote attention switches between the two voices, the interferers were uttered by the same talker as the target stories, but the voice parameters were manipulated to parametrically control the similarity of the two voices. We will discuss the results in terms of attentional selection and voice confusion, and suggest possible applications of this dynamic behavioral test of selective auditory attention.
Ability of normal hearing listeners to recognize vowels and musical instruments under spectrally-degraded conditions
Authors: Anderson Ryan , Sundheimer Alyxandria , Shofner William
Published: April 2019

Music perception requires greater spectral resolution than speech perception [Shannon, Int. Rev. Neurobiol. 70, 121 (2005)]. However, conclusions from these metadata are problematic given that they aggregate results from several different studies using diverse methodologies and paradigms. In particular, methodologies generally tapped into different perceptual dimensions, namely word recognition for speech and melody recognition for music. The present study aims to develop a paradigm to compare speech and music recognition based on similar perceptual dimensions, namely timbre. Stimuli consisted of naturally-spoken vowels and notes played on musical instruments as well as 32-, 8-, and 4- channel noise-vocoded versions. Listeners discriminated either instruments from vowels or vowels from instruments using a go/no-go task. The discrimination paradigm offered insight as to how available spectral information influenced perception between stimulus sound categories. Reaction times and accuracy were measured and organized as a function of signal degradation level to consider potential differences in how normal hearing listeners utilize spectral fine structure information when distinguishing vowels and musical instruments. In general, listeners’ ability to discriminate vowels from instruments under degraded conditions was similar to their ability to discriminate instruments from vowels. The results suggest that the perception of vowels and musical instruments rely on similar mechanisms.
The fine-grained statistical structure of speech is congruent with nonlinear peripheral auditory processing
Authors: Deloche François
Published: April 2019

Efficient coding of sensory signals takes advantage of statistical regularities in sensory data. Cochlear filter in mammals are known to reflect the overall statistical structure of speech, in line with the hypothesis that low-level sensory processing provides efficient codes for information contained in natural stimuli. Recently, some efforts have been made to describe this correspondence in more detail. The study of the statistical structure of speech over different acoustic classes demonstrates that frequency selectivity should not be fixed to achieve maximum efficiency. On the other hand, cochlear signal processing is nonlinear as frequency selectivity decreases with sound intensity level. Both effects are greater in the high frequencies. In the present study, these two facts are shown to be consistent in the case of a parametric method based on Gabor dictionaries (Gaussian-modulated sinusoids) and in a simplified setting. A model with fewer constrains is also introduced for future experiments to validate this hypothesis in a more general context.