bluuebunny/crossref_metadata_2025 huggingface dataset:
Child-directed speech in noise: Listener- and environment-related changes in speech acoustics
Authors: Smith Nicholas A. , Hammans Christine A. , Vallier Timothy J. , McMurray Bob
Published: April 2019

Talkers adapt their speech in various ways according to the demands of their listeners and the communicative context. Mothers and their preschool children participated in a real-time interactive speech production/perception paradigm, in which mothers instructed their children (or an adult listener), to select the picture corresponding to the target word. The task was performed at low and high levels of background noise (56 and 76 dB SPL, delivered through headphones), to examine the effects of decreased audibility on speech production. Acoustic-phonetic analyses of child-directed speech (CDS) and adult-directed speech (ADS) productions of target words and carrier phrase (e.g., “Find pig” ), revealed that mothers significantly enhanced the suprasegmental properties (i.e., pitch, intensity, and duration) of target words in CDS and at higher noise levels, but provided limited evidence for the hyperarticulation of the segmental properties of speech (i.e., formant frequencies of vowels, or voice-onset times of stop consonants). Results suggest that while some aspects of articulatory control are readily amenable to change as function of task/listener demands, others may not be. Understanding these capacities and constraints in the talking caregiver is relevant to theories of hyperarticulation in infant-directed speech.
Distributed sensing for acoustic source localization in indoor reverberant environments
Authors: Bertolino Angela , Gandhi Pratik , Joasil Arielle , Obi Chester , Chandra Kavitha , Thompson Charles
Published: April 2019

The acoustic source localization problem relies on the estimate of the difference in time-delays of the signal received between a pair of acoustic sensors separated by a fixed distance. In the ideal case of a room with no reflections, one can identify the intersection of constant power level maps generated by multiple pairs of sensors to isolate the location of the source. The presence of reverberation however produces additional potential source locations that create uncertainty in the source location. In this research, impulse responses are simulated for a rectangular room using an image source model that incorporates frequency dependent absorption coefficients. These spatio-temporal impulse responses are applied in conjunction with room noise to simulate the signals recorded across a two-dimensional distribution of sensor pairs. The number of sensor-pairs and their spatial distribution that can optimally predict the source location in the presence of reverberant features is discussed.
Pentagalloyl glucose effects on murine abdominal aortic aneurysms
Authors: Anderson Jennifer L. , Berman Alycia G. , Niedert Elizabeth E. , Patnaik Sourav , Finol Ender A. , Goergen Craig J.
Published: April 2019

An abdominal aortic aneurysm (AAA) is a dilation of the abdominal segment of the largest artery in the body and can be accompanied by significant risk of rupture and mortality. The current treatment, surgical repair, carries risks and complications. As such, there is need for less invasive therapies capable of curbing aneurysm growth. Here we use an AAA mouse model to evaluate the potential of pentagalloyl glucose (PGG) to suppress aneurysm growth. To induce aneurysms, 5.0 mg/mL pancreatic porcine elastase (PPE) was topically applied to the infrarenal aorta and 0.2% beta aminoproprionitrile was continuously administered via drinking water. Four of the eight animals also received topical treatment of 0.06% PGG via gauze before PPE treatment. High frequency ultrasound imaging (Vevo2100 system, VisualSonics) with a MS550D transducer (40 MHz center frequency) was performed prior to surgery, and every week thereafter for 4 weeks. PGG-treated animals had a small but nonsignificant decrease (p = 0.09) in effective maximum aortic diameter on days 7 and 14 that was not present on day 28. Current work is being performed to quantify PGG binding via histological characterization. Ultimately, we aim to investigate the parameters required for PGG to be an effective treatment for mechanically-stabilizing small AAAs.
Empowerment through POMA: How conference proceedings help students publish
Authors: Gee Kent L.
Published: April 2019

When it comes to publishing research results in a thesis or journal article, a disconnect between advisor expectations and student abilities and motivation can be a source of frustration, fear, and deteriorated relationships. Publishing in conference publications, including Proceedings of Meetings on Acoustics (POMA), represents an opportunity to bridge this gap. This presentation describes several benefits of publishing in conference proceedings, how to use POMA as a springboard, and some suggestions to help students and advisors overcome the barriers to publication.
Consequences in standardizing the soundscape data collection process
Authors: Fiebig André
Published: April 2019

The ISO/TS 12913-2 dealing with data collection and reporting issues in the context of soundscape investigations was published in 2018. This technical specification proposes a range of methods and tools to perform the data collection process according to the current understanding of the soundscape approach. It intends to harmonize the data collection of soundscape studies and to ensure a certain level of comparability between soundscape investigations. In the past the vast majority of soundscape studies applied very different methods and tools limiting the comparability of results and avoiding the performance of meta-analyses. The reason might be the interdisciplinary roots of the soundscape concept asking for diverse disciplinary accesses to the phenomenon challenging the soundscape standardization efforts. Now, the disadvantage of the limited comparability of soundscape results might be overcome due to the publication of the ISO/TS 12913-2. The paper will discuss the expected impact of the technical specification defining the data collection requirements on soundscape research and will highlight the benefits and potential drawbacks in standardizing the holistic soundscape approach.
Prediction model of soundscape assessment based on semantic and acoustic/psychoacoustic factors
Authors: Yang Ming
Published: April 2019

While conventional sound/noise environment assessment, management and relevant standards are based on the objective measurement of sound pressure level (SPL), soundscape research showed that humans’ subjective assessment (such as positive and negative) cannot be well explained by the SPL or other acoustic indicators alone. Rather, soundscape assessment depends on many more factors such as cognition and context, which also need to be considered as suggested in the new soundscape standard. Among the different factors, a large number of previous studies supported that semantic factors, i.e. the sound sources which compose the sound environment—e.g., natural sounds (moving water, bird song, etc.), mechanical sounds (road traffic, construction, etc.) and human activity sounds, play the most important role in human perception and assessment. Therefore, from the systematic literature review of the relationship between such semantic factors and soundscape assessment, this present study proposes a model based on the sound source information, as well as SPL and psychoacoustic indicators of each of the different sound sources, to explain/predict largely, even though not fully, the soundscape assessment. Furthermore, for the practical use of this model which would be independent of manual efforts in recognition of sound sources through listening, this study discusses the possibility of integrating a computer algorithm of sound source recognition from field recordings of sound environment, for automated soundscape assessment.
Automated parsing of sound level meter data into artifacts, natural sources, and noise
Authors: Fristrup Kurt M.
Published: April 2019

The National Park Service (NPS) has nearly one million hours of 1/3rd octave band sound level measurements collected at hundreds of sites throughout the system. One of the principal purposes of these data is to measure the background or residual sound level against which all transient sounds are heard. Historically this analysis has depended upon trained listeners to identify which sound sources can be heard in segments of these data. These annotated records were then used to calculate an adjusted median sound level. To pursue a more efficient, automated method to deliver this result, matrix decomposition methods were tested to characterize their capacity to model time series of sound level spectra as low-rank decompositions, including options to account for anomalous events. These methods were combined with sound source identification based on component spectral properties and time weightings to yield promising approaches for automating NPS analyses. These results may also offer options for detecting and removing the effects of pseudonoise due to the turbulence generated by air flowing past the microphone.
Nonlinear acoustic metamaterials
Authors: Wallen Samuel P. , Hamilton Mark F. , Haberman Michael R.
Published: April 2019

Acoustic metamaterials (AMM) have become a very active topic for research in numerous domains of engineering and science because of their promise to create materials, structures, and devices that can control acoustic wave propagation in ways that exceed the capabilities of naturally occurring or conventional composite materials. The majority of AMM research has been focused on linear behavior such as negative dynamic effective stiffness and density, cloaking, and negative refraction. One drawback of the focus on linear behavior is the restriction of the effective material properties of interest to narrow frequency bands that cannot be changed with external stimulus. Nonlinearity has been explored as a means of increasing the bandwidth of performance by enabling tunable band gaps and material configurability. Other recent work has investigated nonlinear AMM to access phenomena such as harmonic generation, non-reciprocity, enhanced energy absorption, solitons, mode hopping and conversion, chaos, and intrinsic localized modes. This talk will provide an overview of nonlinear AMM, starting with a background on AMM, then surveying existing research on the topic and its relationship to seminal works in nonlinear acoustics, and finally discussing promising avenues of future research. [Work supported by the National Science Foundation EFRI program and ARL:UT.]
Modeling of plane progressive waves in media that exhibit slow dynamics and dissipative nonlinearity
Authors: Cormack John M. , Muir Thomas G. , Hamilton Mark F.
Published: April 2019

Nonclassical nonlinearity refers to amplitude-dependent effects that are irreversible, for example slow dynamics and dissipative nonlinearity, both phenomena that are commonly observed in materials such as sandstone and concrete. Analyses of progressive waves in such media have been few, and have relied on hysteresis models that are difficult to implement, especially for transient or strongly nonlinear pulses. In this work, an evolution equation for plane progressive waves in a nonclassically nonlinear material is derived using two phenomenological models: the internal variable model of Berjamin et al. for slow dynamics [Proc. Roy. Soc. A 473, 20170024 (2017)], and a simple model for dissipative nonlinearity [Zaitsev and Nazarov, Acoust. Phys. 44, 362 (1998)]. The evolution equation is easily solved numerically given an arbitrary initial waveform. An initially narrowband signal exhibits pulse lengthening, amplitude-dependent attenuation, and nonclassical waveform steepening during propagation. Experimental observation of the same phenomena were reported recently by Remillieux et al. [J. Geophys. Res. 122, 8892 (2017)]. Their results are reproduced in this study using the new evolution equation, showing good agreement between the model and the measurements, with additional insight into the behavior of the material gained from the model. [J.M.C. supported by the ARL:UT McKinney Fellowship in Acoustics.]
Revisiting perceived intracranial lateralization for stimuli with interaural time differences that are larger than the head
Authors: Goupell Matthew , Best Virginia , Nothaft Julia , Colburn H. Steven
Published: April 2019

The interaural time difference (ITD) is the primary sound-localization cue for humans. While realistic sound sources have energy across a wide frequency range, the ear performs a narrowband frequency decomposition, and within each band are ambiguities in the interaural cross-correlation (an index of the signal ITD). These ambiguities are thought to be resolved by the approximate consistency of ITDs across frequency, or “straightness.” However, straightness has not been evaluated over a wide range of stimuli. Therefore, normal-hearing listeners reported the intracranial lateralization of narrowband noises and tone complexes to better evaluate across-frequency ITD processing. In a new modification of the typical paradigm, listeners were encouraged to give multiple responses if split images were perceived. ITDs larger than those naturally produced by the head (~750 ms) best demonstrate straightness because across-frequency comparison is necessary to resolve the interaural phase ambiguities, which is why ITDs as large as 1500 ms were applied. Straightness effects reported previously for narrowband noises were replicated, and were broadly similar for complex tones. The extent of lateralization of 1500-ms ITDs and the occurrence of split images were difficult to account for using simple lateralization-based models for smaller ITDs.
Plate mechanical metamaterials and their applications
Authors: Bargatin Igor
Published: April 2019

Recently, we introduced the concept of plate mechanical metamaterials—cellular plates with carefully controlled periodic geometry and unique mechanical properties—as well as its initial realization in the form of freestanding corrugated plates made out of an ultrathin film. We used atomic layer deposition (ALD) and microfabrication techniques to make robust plates out of a single continuous ALD layer with cm-scale lateral dimensions and thicknesses between 25 and 100 nm, creating the thinnest freestanding plates that can be picked up by hand. We also fabricated and characterized nanocardboard—plate metamaterials made from multiple layers of nanoscale thickness, whose geometry and properties are reminiscent of honeycomb sandwich plates or corrugated paper cardboard. Ultralow weight, mechanical robustness, thermal insulation, as well as chemical and thermal stability of alumina make plate metamaterials attractive for numerous applications, including structural elements in flying microrobots and interstellar light sails, high-temperature thermal insulation in energy converters, photophoretic levitation, as well as ultrathin sensors and resonators. I will briefly discuss our experimental progress on all these applications, including demonstrations of extremely robust thermal insulators that can sustain a temperature difference of ~1000 °C across a micron-scale gap, macroscopic plates that levitate when illuminated by light, and hollow AFM cantilevers that offer greatly enhanced sensitivity and data acquisition rates.
Synchronization and avalanching amongst coupled phase oscillators, mechanical lasing
Authors: Coleman John P. , Weaver Richard
Published: April 2019

We present theory and numerical simulations for two nonlinear systems consisting of a large number of eccentrically-weighted DC motors on mechanical bases. These are generalizations of the Kuramoto model for synchronizing phase oscillators, one chief difference being that the coupling is now frequency dependent. In one system the base is resonant and has a single degree of freedom. This system exhibits the expected second order phase transformation: for sufficient coupling strength the motors synchronize with a power output that grows with the distance above criticality. In the synchronized state the base oscillates at a single frequency (below its nominal resonance) with an amplitude that rises superluminescently with the number of motors. The degree of synchronization fluctuates intermittently, with statistics similar to those of universal crackling noise and avalanches. In our other system the motors are placed densely on a tensioned membrane, with sound speed such that wavelength is large compared to motor size and spacing. As such the structure is an active nonlinear metamaterial. As a function of coupling strength we observe a lasing transition from a near-quiescent state to a state in which the membrane is dominated by a single wavelength, and acoustic power emission is high.
Quantifying child directed speech cross-culturally across development
Authors: Soderstrom Melanie , Casillas Marisa , Bergelson Elika , Kirby Jessica , Rosemberg Celia , Stein Alejandra , Warlaumont Anne , Bunce John
Published: April 2019

Child-directed speech (CDS) influences language development (e.g., Golinkoff et al., 2015), but varies across cultural and demographic groups (Hoff, 2006). Recent work examining speech heard by North American English (NAE) infants found an increased proportion of CDS with age (Bergelson et al., 2018). Quantity of CDS remained relatively constant across age, while quantity of adult-directed speech (ADS) decreased. We replicate these findings using a different methodology, and expand them to include other language communities. Our data come from daylong audio recordings of 58 children ages 2–36 months from the ACLEW dataset (Bergelson et al., 2017; 30 children acquiring NAE, 10 UK English, 8 Argentinian Spanish, and 10 Tseltal/Mayan). Ten randomly selected 2-min segments (Tseltal: nine 5-min segments) from each child were annotated for speaker gender, age (child or adult), and addressee for each utterance. We calculated the minutes per hour of CDS, ADS, and all speech. Preliminary analyses find high variability in overall language input across individuals, age, and culture, and partially replicate the Bergelson et al. (2018) pattern of results. Ongoing annotation will permit finer-grained analyses of sub-group differences. Further analyses will examine the influence of factors such as speaker gender, number of speakers, and maternal education.
Applications of finite-difference time-domain for architectural acoustics consulting
Authors: Brill Laura C. , Strong John T.
Published: April 2019

Acoustics consultants have many tools in their arsenal to evaluate and design rooms and architectural elements; the computational resources available to this point have made the use of wave-propagation models impractical for the common user. Threshold acoustics has found it both useful and now computationally feasible to supplement more traditional, geometric analysis with the simulation of wave-propagation using finite-difference time-domain (FDTD). Our group has developed first-order leapfrog FDTD routines in MATLAB for simulating wave propagation in an isotropic medium in two- and three-dimenision with perfectly matched layers being the boundary condition. The placement of solid elements within the test space allows analysis of arbitrary geometries. For additional computational power, our group has utilized GPU computing clusters available through Amazon Web Services accessed directly through MATLAB. Our method is based on the simulation of an impulse response and subsequent analysis of the impulse response consistent with traditional in situ testing methods. Applications to date include analysis of the scattering behavior of acoustically shaped surfaces and evaluation of the array behavior of architectural reflector panels.
Acoustofluidics: Merging acoustics and microfluidics for biomedical applications
Authors: Huang Tony Jun
Published: April 2019

The past two decades have witnessed an explosion in lab-on-a-chip research with applications in biology, chemistry, and medicine. Recently, a new lab-on-a-chip frontier has emerged, joining acoustics with microfluidics, termed acoustofluidics. Here, we summarize our recent progress in this exciting field and show the depth and breadth of acoustofluidic tools for biomedical applications through many unique examples, including exosome separation, cell-cell communication studies, three-dimensional bioprinting, circulating tumor cell isolation and detection, ultra-high-throughput blood cell separation, high-precision micro-flow cytometry, and portable fluid manipulation systems. These acoustofluidic technologies are capable of delivering high-precision, high-throughput, and high-efficiency cell/particle/fluid manipulation in a simple, inexpensive, cell-phone-sized device. More importantly, the acoustic power intensity and frequency used in these acoustofluidic devices are in a similar range as those used in ultrasonic imaging, which has proven to be extremely safe for health monitoring during various stages of pregnancy. As a result, these methods are extremely biocompatible, i.e., cells and other biospecimens can maintain their natural states without any adverse effects from the acoustic manipulation process. With these advantages, acoustofluidic technologies meet a crucial need for highly accurate disease diagnostics (e.g., early cancer detection and monitoring of prenatal health) and effective therapy (e.g., transfusion and immunotherapy).
Variability in context effects on rate adaptation within individuals
Authors: Heffner Christopher C. , Myers Emily B.
Published: April 2019

Rate adaptation is a crucial aspect of speech perception. Listeners can rapidly adapt to a wide variety of speech rates. Recent evidence has indicated that these effects can emerge even over the course of single sentences: studies of what are often termed “distal context effects” have shown that the rate context at the beginning of a sentence can affect the perception of words at the end of a sentence. These effects have been found across contrasts and languages. Yet the consistency of these effects within individuals has almost never been probed. Here, we report a series of experiments that examined whether distal context effects are consistent within individual talkers. We find surprisingly low test/retest reliability in distal context effects. Namely, the strength of the effects within individuals in one session or in one set of items had almost no bearing on the strength in a second session or second set of items. This was true even when the item set was highly constrained, to mitigate item effects in the stimuli. This suggests that a more nuanced understanding of individual variation in context rate effects is necessary.
Cross-linguistic pitch differences in bilingual speakers
Authors: Cheng Andrew
Published: April 2019

Studies in cross-language pitch differences show that languages can fundamentally differ in average pitch range even when speaker differences are accounted for (e.g., Mennen et al., 2012). Such studies usually compare similar populations of monolingual speakers but not bilingual speakers of the languages in question. Bilingual development research, in turn, does not address average language pitch but rather segmental properties such as vowel formants. The current study fills the gap by examining the fundamental frequency (f0, or pitch) of both languages of English-Korean bilinguals. Twenty Americans of Korean descent (female = 13, average age = 24) recorded natural speech during a bilingual interview. Their speech was digitally recorded and transcribed, and f0 was analyzed using the inverse filter control method (Ueda et al., 2007). Average f0 per word, per language, and per subject was then calculated and compared across individuals and groups. Results showed that Korean has significantly higher f0 than English, regardless of gender or age. The implications for research in acoustics and speech communication include a greater consideration for bilingualism or bilingual modes of speech as a variable, as well as an open line of inquiry into further study of cross-language differences within the bilingual speaker, including as a result of code-switching.
Public health impacts from subway noise: Case study Hong Kong
Authors: Xu Stephany Y. , Jiang Changyong , Huang Lixi
Published: April 2019

In cities, subway noise is often cited as a major contributor to noise pollution that impacts millions of people every day. Previous studies on this topic have shown that peak subway noise levels in some cities can be as high as 110 dB, which greatly exceeds the 70 dB level set by the World Health Organization (WHO) and EPA for safe environmental noise levels. This work aims to characterize the subway noise in Hong Kong, analyze potential source features, and make technical recommendations for consideration by government and metro companies. First, the overall noise data on all nine subway lines in the city are presented and compared with published data of other subway lines around the world. Spectra of the loudest segments are analyzed to show the effects of tunnel modes, track curvature, and other features that may play a significant role in noise radiation and reverberation. A detailed correlation study is conducted for the short-time noise level and vehicle speed. A new train speed profile that optimizes noise exposure reduction is proposed for consideration of a future auto-drive system. Finally, a study of vibroacoustic exposure by passengers is also conducted to examine the impacts beyond the audible frequency range.
Investigating the role of temporal fine structure in everyday hearing
Authors: Borjigan Agudemu , Bharadwaj Hari M.
Published: April 2019

Human listeners can derive substantial masking release when there are discrepancies in pitch or spatial location between the target and masking sounds. While the temporal fine-structure (TFS) in low-frequency sounds can convey information about both pitch and location, a nuanced debate exists in the literature about the role of these TFS cues in masking release. The long-term goal of the present study is to leverage individual differences to understand the role of TFS in everyday hearing. As a first step, we sought to measure individual TFS sensitivity using monaural frequency modulation (FM) and binaural interaural time difference (ITD) detection tasks. Preliminary data show large individual differences in these measures. Moreover, individual differences in ITD sensitivity were correlated with monaural FM sensitivity suggesting that monaural TFS coding can be a primary bottleneck determining binaural sensitivity. Alternately, both FM and ITD sensitivity variations could be reflecting common non-sensory factors (e.g., attention). To disambiguate between these hypotheses, we designed two passive EEG metrics of TFS coding. Follow-up experiments will compare individual differences in these perceptual and EEG measures to each other, and to speech-in-noise perception in complex environments.
Efficacy of iPad “spatial release” application
Authors: Holtz Allison , Clark Kelli , Srinivasan Nirmal Kumar
Published: April 2019

Spatial Release from Masking (SRM) is the ability to obtain better speech recognition thresholds when the maskers are spatially separated from the target. Here, we present SRM data collected using three techniques: over headphones using a virtual speaker array, using Spatial Release iPad application (https://bgc.ucr.edu/games/spatialrelease/), and loudspeaker presentation in a sound-attenuated room. For all three techniques, Coordinate Response Measure (CRM) sentences were used as the stimuli, and “Charlie” was the call sign. A progressive tracking procedure was used to estimate the Speech Recognition Thresholds (SRTs) for listeners with varying hearing thresholds. The target sentence was always presentedg at 0 deg azimuth angle whereas the maskers were colocated (0 deg) with the target or symmetrically spatially separated by ±15 deg, ±30 deg, or ±45 de. Initial data analysis revealed similar SRTs for the iPad and headphone conditions and slightly poorer thresholds for the loudspeaker array condition. This was true for all spatial separations between the target and the maskers. The individual effects of age and hearing loss on spatial release from masking will be discussed. These data will aid clinicians to rapidly characterize difficulties perceived by individuals in everyday listening scenarios and to evaluate patient progress with hearing aid adjustments and aural rehabilitation over time.
Portable psychoacoustics with passive and active noise-attenuating headphones
Authors: Lelo de Larrea Mancera Esteban S. , Stavropoulos Trevor , Gallun Frederick J. , Eddins David A. , Hoover Eric C. , Seitz Aaron
Published: April 2019

This presentation will describe data collected using a freely available procedure for psychoacoustical testing that harnesses commercially available tablet computer technology to address the current gap between (1) modern auditory neuroscience and psychophysics and (2) current clinically available tests of hearing. Portable Automated Rapid Testing (PART) measures running on an iPad were used to evaluate the detection of (a) tones in noise; (b) spectral, temporal, and spectro-temporal modulation; (c) monaural and binaural frequency modulation; and (d) brief temporal gaps inserted between brief tone pulses. Listeners also performed a spatial release from speech-on-speech masking task. Data from 151 UCR undergraduates were collected using both passive and active noise-attenuating headphones in a quiet environment and in the presence of recorded cafeteria noise. Across these and several other manipulations of equipment and threshold-estimation techniques, performance approximated that reported in the literature. These data provide a distribution of thresholds that can now be used as a normative baseline against which auditory dysfunction can be identified in future work.
Evaluating new hearing aid technologies in laboratory simulations of listening scenarios
Authors: Nelson Peggy B. , Anderson Elizabeth , Perry Trevor T. , Oeding Kristi , Byrne Andrew
Published: April 2019

It can be important for clinical researchers to be able to evaluate the performance of sensory aids using both objective and subjective methods. New technology (such as self-fit hearing aids) can be evaluated in a laboratory setting in calibrated listening scenarios that reflect daily listening situations. In the Center for Applied and Translational Sensory Science (CATSS) multisensory laboratory, we have developed simulations of challenging conversational scenarios so that users of sensory aids can make judgments of sensory aid performance in realistic but controlled conditions. Listeners with hearing loss make ratings of intelligibility, sound quality, and preference in scenarios such as small group conversations and entertainment listening. At the same time, measures of hearing-aid gain and speech intelligibility are obtained. These ratings are compared to outcome measures such as the Speech, Spatial, and Qualities of Hearing Scale (SSQ; Gatehouse and Noble, 2004) and Social Participation restrictions questionnaire (SPaRQ; Heffernan et al., 2018) to determine relationships between intelligibility, preference, benefit, and hearing aid gain. Results will help refine methods for evaluating the performance of emerging technologies for hearing loss. [Work supported by NIDCD R01 DC 13267.]
The effects of age on narrowband and broadband measures of spectral processing in listeners with hearing loss
Authors: Oeding Kristi , Davies-Venn Evelyn E.
Published: April 2019

The propensity for degraded auditory perception increases with age. Several studies have shown that while age-related hearing impairment explains a high percentage of the often-reported degradation in auditory perception, there still remain some effects that can only be attributed to the aging process. Even though some classic studies have shown that spectral processing may be immune to age-related degradation, some recent work with broadband measures of spectral processing appears to challenge this notion. This study evaluated the effect of age on narrowband and broadband spectral processing abilities for individuals with mild-to-moderate hearing loss. We controlled for the amount of hearing loss and measured auditory filter bandwidths using notched-noise masking and spectral modulation detection using rippled noise in the same cohort of listeners. Results to date suggest that broadband spectral processing, which uses stimuli that share ecological validity with speech, may be more sensitive to age-related changes in spectral processing compared to narrowband spectral processing.
Broadband sound localization with gradient helical structure
Authors: Zhu Jie
Published: April 2019

Acoustic sensors or microphones are essential equipments for the detection of sound signals. However, sound signal suffers from the inevitable attenuation due to many reasons, such as diffusion, damping, thermal, and viscous loss. To solve such a problem, we introduce a gradient acoustic metamaterial to magnify the sound signal before it can be coverted to the electrical signal by introducing a gradient refractive index along the sound propagating route. In this case, the acoustic signal can be magnified as the wave is compressed by the gradient increasing index. The helicoid metamaterial has the advantage to adjust acoustic parameters flexibility and continuity by changing the pitch of the blades. This design is of great significance to improve the working condition of signal detection and may contribute to the design of other sensors.
Resonance frequencies of a spherical aluminum shell subject to prestress from internal fluid pressure
Authors: Piacsek Andrew A. , Harris Natalie
Published: April 2019

Vibration measurements of a spherical aluminum shell (6 in. diameter) filled with water show that the resonance frequencies of the shell shift higher or lower with increasing water pressure, depending on the specific mode of vibration. For a given mode, the rate of frequency shift with pressure change Δf/Δp is approximately linear for gauge pressures up to 100 psi. Frequency shifts were detected for pressure changes as small as 0.2 psi or 10 mm Hg. Observations of positive frequency shifts are consistent with previous studies (from the 1950s) involving submerged cylindrical shells subject to much larger pressures. Analysis from this era suggests that the phenomenon is due to geometric nonlinearity; however, the negative frequency shift observed with low order modes is not predicted by this theory. The feasibility of developing a noninvasive method for monitoring intracranial pressure using shifts in skull resonance frequencies will also be discussed.
Classification of inter-floor noise type/position via supervised learning
Authors: Choi Hwiyong , Yang Haesang , Lee Seungjun , Seong Woojae
Published: April 2019

This work presents noise type/position classification of various inter-floor noises generated in a building which is a serious conflict issue in apartment complexes. For this study, a collection of inter-floor noise dataset is recorded with a single microphone. Noise types/positions are selected based on a report by the Floor management Center under Korea Environmental Corporation. Using a convolutional neural networks based classifier, the inter-floor noise signals converted to log-scaled Mel-spectrograms are classified into noise types or positions. Also, our model is evaluated on a standard environmental sound dataset ESC-50 to show extensibility on environmental sound classification.
Effect of uncertainty in meteorological conditions on aircraft noise levels
Authors: Patankar Harshal Prakash , Sparrow Victor
Published: April 2019

To comply with noise regulations and to plan infrastructure around airports, there is a need to accurately predict aircraft noise levels. Even when high fidelity noise propagation models are used, the accuracy of noise level predictions can be affected by uncertainty in the input parameters. This work looks at the change in SPLs due to these uncertainties. To incorporate the effect of meteorological uncertainties, the methodology presented in Wilson et al. [JASA(2014)] is extended to the geometry of aircraft noise propagation. To allow for faster computations, a simplified version of the NORD 2000 noise propagation method is used. This work explores the effect of individual meteorological uncertainties in the propagation path (such as temperature profile and wind profile) as well as their combined effect on the SPLs for terminal area aircraft altitudes. [Work supported by the U.S. Federal Aviation Administration Office of Environment and Energy through ASCENT, the FAA Center of Excellence for Alternative Jet Fuels and the Environment, project 40 through FAA Award No. 13-C-AJFE-PSU under the supervision of Hua He. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the FAA.]
Reverberation time and audibility in phased geometrical acoustics using plane or spherical wave reflection coefficients
Authors: Boucher Matthew , Rychtarikova Monika , Zelem Lukas , Pluymers Bert , Desmet Wim
Published: April 2019

In acoustical spaces, room acoustic parameters are often predicted using energy-based geometrical acoustics. For smaller rooms, interference among coherent reflections is taken into account by phased geometrical acoustics, which improves results for lower frequencies. The use of a spherical wave reflection coefficient improves the results further, yet the impact on room acoustic parameters is not fully known. This work focuses on the differences in predicted reverberation time when using plane or spherical wave reflection coefficients. The differences are analyzed for a variety of boundary conditions, including non-uniform distributions of absorption, in medium-sized rooms using a phased image source model. Since calculated differences are greater than the conventional just-noticeable-difference of 5% for reverberation time, a laboratory listening test is performed to confirm audibility of the modeled differences. Two narrow band noise stimuli (octave bands with central frequencies of 125 and 250 Hz) with a duration of 1 s were used for comparisons of 18 acoustic scenarios by means of a three-alternative forced choice method (3AFC). More than half of the listeners could hear the differences in all 36 cases. Statistically significant results (chi-squared test was used) were found in two thirds of the cases, corresponding to those with longer reverberation times.
Diffraction simulation from wedges to finite-sized plates based on the physical theory of diffraction
Authors: Xiang Ning , Savino Anthony , Rozynova Aleksandra
Published: April 2019

Efficient predictions of sound diffraction around objects are of critical significance in room-acoustic simulations. An advanced diffraction theory has recently been investigated for potential applications in room acoustics for some semi-infinite, canonical wedges and for finite-sized rectangular plates [Rozynova and Xiang, J. Acoust. Soc. Am. 144 (to be published)]. The physical theory of diffraction (PTD) still relies on both geometrical and physical principles, yet emphasizes the physical one. Important features of the PTD approach are its computational efficiency and the high degree of accuracy for the diffracted sound field. This paper reviews the fringe field predictions of canonical semi-infinite wedges and further discusses solutions of diffraction problems on finite, rigid rectangular plates. The PTD is applied to approximate the solutions of a finite-sized, rigid rectangular plate that achieves high numerical efficiency. The PTD simulation allows sound diffraction contributions to be determined independently from two pairs of edges of the rigid plate, while ignoring the edge waves around the corner in far-field. This paper uses numerical implementations of the PTD predictions to demonstrate the simulation efficiency of the PTD in finite-sized objects. The numerical simulations are also validated by some preliminary experimental results carried out using an acoustic goniometer.
Discrete material optimization for wave-based acoustic design
Authors: Morales Nicolas , Manocha Dinesh
Published: April 2019

The problem of automatic design of acoustic spaces is prevalent in architecture and room acoustics. We present a novel algorithm to automatically compute the optimal materials of large architectural spaces. Our method uses discrete optimization techniques to determine the best material configuration for desired acoustic properties of a structure, while taking into account properties of real-world materials. An efficient acoustic wave solver is used to accurately compute the acoustic impulse responses that drive the optimization process. Our method is tested on various computer representations of real-world scenes where we show how new material characteristics can be computed to improve the scene's strength, clarity, and reverberation time.
Development of high frequency ultrasound-based technique to increase cell permeability
Authors: Yoon Sangpil , Wang Yingxiao , Shung K. K.
Published: April 2019

Ultra-high frequency ultrasonic transducers have been developed by limited groups for cellular applications and high resolution imaging purposes. We have developed 150 MHz ultrasonic transducers with a focal size of smaller than 10 µm to increase permeability of cells to introduce macromolecules into cell cytoplasm. Cell-based therapy has enormous potential to treat neurodegenerative disease and cancer by engineering cells. One of the main challenges in cell-based therapy has been the safe intracellular delivery of macromolecules such as proteins and nucleic acids. We have developed a high frequency ultrasound-based technique for simultaneous and targeted single cell intracellular delivery of diverse types of macromolecules by increasing permeability of cell. High frequency ultrasound has a focus with area smaller than a single cell and enough focusing gain to directly disrupt cell lipid bilayer without microbubbles. Extremely thin layer of lithium niobite single crystal was used to generate 150 MHz sound waves. The transducer was integrated with microscope to apply acoustic pulses to increase permeability. CRISPR-Cas9, programmable gene editing tools, were delivered into single cells after the permeability was increased by high frequency ultrasound beam transmitted from the developed high frequency ultrasonic transducers. This study showed that the direct disturbance of cell membrane without microbubbles can be achieved by high frequency ultrasound for the safe delivery of macromolecules by increasing cell permeability.
Engine characterization using experimental method and prediction of insertion loss of the exhaust system
Authors: Chhabra Manish
Published: April 2019

The evaluation of the acoustic performance of an exhaust system at the design stage requires a correlated engine model and reasonably approximate input boundary conditions to simulate the end results, both of which are not easily available. It is known that the input boundary conditions for insertion loss analysis require two engine parameters, namely, source impedance and source strength spectra. This study describes experimental measurements for these parameters using in-duct measurement via the multi-load method for a six-cylinder diesel engine and calculation for insertion loss using GT-Power. The research discusses the approach taken to select the acoustic load cases considered for the multi-load method and then the execution of the test plan for different engine operating conditions The time domain data sets were processed to obtain the frequency spectra and was used to get the impedance of the acoustic load cases and finally the source impedance and source strength spectra for different engine operating conditions. The results obtained using all the acoustic load cases were optimized by filtering out unacceptable load cases and then re-evaluating the source characteristics to use them as input boundary conditions for insertion loss analysis. The analysis results were then compared to the experimental insertion loss.
On a cooling speed comparison a sound fire extinguisher with the blade
Authors: Kim Bong Young , Bae Myungjin
Published: April 2019

Sound Fire Extinguisher, which is actively studied at Sori Sound Engineering Research Institute (SSERI), is a new type of extinguishment facility that can be used for suppression and prevention of conflagration in various environments. Sound Fire Extinguisher uses acoustic lens to minimize the attenuation of sound energy and transfer energy to the target point. It can prevent conflagration by lowering ambient temperature even before conflagration. In this study, we experimented to see if the Sound Fire Extinguisher could prevent conflagration by lowering the ambient temperature. Experimental results show that when the Sound Fire Extinguisher sound component of the same wind speed is supplied, the heated tableware is cooled by 10%–20% faster than the wind speed of 2 m/s. These results show that the Sound Fire Extinguisher can be used to prevent conflagration, since the sound component of the Sound Fire Extinguisher itself promotes the surrounding thermal dissipation to cool quickly.
Ultimate wave decomposition method for characterization of symmetric and asymmetric materials
Authors: Ghaffarivardavagh Reza , Wu Rui , Anderson Stephan , Zhang Xin
Published: April 2019

To date, several approaches leveraging impedance tubes have been proposed to retrieve the complex acoustic reflection and transmission coefficient through the materials. In these approaches, commonly, accurate derivation of the reflection and transmission relies on the several assumptions such as material symmetry or the type of the terminations (load) used in the impedance tube. Herein, we have proposed an Ultimate wave decomposition approach (UWD) that may be employed for the precise derivation of the reflection and transmission coefficients, regardless of the termination type. Moreover, it is demonstrated that by employing the UWD method, utilizing single arbitrary termination, symmetric material, and two arbitrary terminations, asymmetric material can be fully characterized. The performance of the presented methodology has been compared experimentally with four different methods with respect to both symmetric and asymmetric cases, from which the superior performance of the UWD method is demonstrated. UWD represents a highly practical approach in which reflection and transmission and consequently acoustical properties of the material, can be precisely measured and calculated using a very simple procedure.
Identification of perceived sound discomfort contributed from partially correlated vibration and noise sources in vehicles
Authors: Huang Yu , Jiang Weikang
Published: April 2019

The interior noise sources are often complex in vehicles, including not only structure-borne and air-borne noise sources but also vibration sources. These sources may be partially correlated and cannot be calculated using traditional methods, e.g., transfer path analysis and operational path analysis. On the other hand, it is necessary to study the sound quality of the vehicle interior noise to improve the comfort of drivers and passengers in vehicles. An operational partial singular value decomposing method together with sound quality analyses was employed in this study to determine the influence of various partially correlated sources with the perceived discomfort of the subject. The vibration and noise in vehicles were measured in a car when it was running on asphalt, concrete, gravel and bumpy roads. Thirty subjects used the absolute magnitude estimation method to rate the discomfort produced by noise stimuli. A discomfort model was proposed based on the relations between subjective magnitudes and the objective parameters of noise (i.e., the SPL, loudness, roughness, sharpness, and articulation index). The contributions of various vibration and noise sources to the vehicle discomfort were predicted well by the operational partial singular value decomposing method based on the discomfort model.