bluuebunny/crossref_metadata_2025 huggingface dataset:
Connecting the sense of envelopment to specific components of the sound field using perceptually motivated auralizations
Authors: Neal Matthew T. , Vigeant Miche C.
Published: May 2015

Envelopment is known to be a key attribute related to overall room impression. Despite this importance, limited research has been done to identify the specific components of the sound field that contribute to envelopment. The goal of this study was to determine the timing and spatial distribution of reflections contributing to envelopment. A subjective study was conducted using a range of simulated auralizations, which were played back over a three-dimensional loudspeaker array in an anechoic chamber. For each auralization, subjects rated their perceived envelopment. A real-time acoustic simulation program was developed in Max to generate the signals, which simulated early sound with the image-source method and late sound with statistical reverberation. When creating the stimuli, the program produced immediate auditory feedback in response to adjusting the input parameters. The signals were quantified through impulse response measurements to ensure a wide range of conditions. The subjects’ envelopment ratings were correlated to different components of the sound field, to evaluate how specific arrival time of reflections and spatial characteristics contribute to envelopment. These results could possibly be used to determine the effectiveness of existing envelopment metrics and potentially contribute to developing a new measure to predict envelopment. [Work supported by NSF Award-1302741.]
Image source model for small room acoustics
Authors: Bhatta Ambika , Thompson Charles , Chandra Kavitha
Published: May 2015

In this investigation, the impulse response obtained using exact solution comprising of the Inverse Laplace transform (ILT) of the direction cosine of the incident angle is undertaken. The results are compared to those obtained by Allen and Berkley (JASA 65, 943–950, 1979). In addition, frequency dependent wall impedance effects are considered. Numerical efficiency and accuracy of the image solution are evaluated.
Simulation and auralization of a concert hall’s inhomogeneous sound field using finite difference time-domain methods and wave field synthesis
Authors: Hochgraf Kelsey , Botts Jonathan , Xiang Ning , Braasch Jonas
Published: May 2015

Auralization methods have been used for a long time to simulate the acoustics of a concert hall for different seat positions. The goal of the research project presented here is to apply the concept of auralization to a larger audience area that the listener can walk through to compare differences in acoustics for a wide range of seat positions. For this purpose, the low frequency acoustics of Rensselaer’s Experimental Media and Performing Arts Center (EMPAC) Concert Hall are simulated using finite difference time-domain (FDTD) methods to create signals for a 128-channel wave field synthesis (WFS) system located at Rensselaer’s Collaborative Research Augmented Immersive Virtual Environment (CRAIVE) Laboratory. By allowing multiple subjects to dynamically experience the concert hall's acoustics at the same time, this research gains perspective on what is important for achieving objective accuracy and subjective plausibility in a simulation and auralization. Efforts are made to maintain efficiency of wave-based modeling, and methods for evaluating the final auralization are explored from both objective and perceptual standpoints.
Reddit Science AMA: Using “the front page of the internet” to share your knowledge with the world!
Authors: Kloepper Laura , Pyzdek Andrew
Published: May 2015

The social media service and link aggregator reddit is one of the most popular and influential websites on the internet. Boasting 174 million unique visitors per day, a high percentage of those high school and college aged students, reddit provides the perfect audience for science outreach. One of the features of reddit is Science AMA, or Ask Me Anything, in which scientists answer questions about their work. Participation in these Q&As allows scientists to communicate with an international audience of all ages and backgrounds, and is an effective tool for scientific outreach with limited time investment. In this talk, we will share the outcome of a Bioacoustics AMA conducted at the Indianapolis meeting, and learn how more individuals and TCs can participate in future Science AMAs.
Top-down linguistic categories dominate over bottom-up acoustics in lexical tone processing
Authors: Zhao Tian C. , Kuhl Patricia K.
Published: May 2015

Native tonal-language speakers exhibit reduced sensitivity to lexical tone differences within categories when compared to across categories (i.e., a top-down linguistic influence). However, increasing evidence suggests enhanced sensitivities to lexical tones among musically trained individuals (bottom-up influence), though previous studies examined non-tonal language speakers processing lexical tones. We investigated the relative contribution of top-down and bottom-up processing of lexical tones when both strategies are available. Seventeen native Mandarin speakers with extensive musical training completed a music test and a lexical tone discrimination task. The music test validated their enhanced pitch-processing abilities. The lexical tone discrimination task measured participants’ lexical tone sensitivities along a continuum. Results were compared to existing data from Mandarin non-musicians and English speaking musicians (Zhao & Kuhl, 2012). Despite their enhanced bottom-up pitch processing, Mandarin musicians’ performance exhibited patterns similar to Mandarin non-musicians, reflecting the dominant influence of linguistic categories (p = 0.504). Their sensitivities were also lower than English-speaking musicians (p = 0.011). However, further regression analysis suggests that bottom-up processing still plays a role in Mandarin musicians: their within-category tone discrimination is predicted by their musical pitch discrimination scores, similar to English musicians but opposite Mandarin non-musicians.
Sentence recognition in temporal modulated noise for native and non-native listeners: Effect of language experience
Authors: Guan Jingjing , Liu Chang , Tao Sha , Li Mingshuang , Wang Wenjing , Dong Qi
Published: May 2015

Speech recognition in adverse listening conditions is more difficult for non-native listeners than native listeners. Previous work in our laboratories found that Chinese-native listeners with native English exposure may improve the use of temporal cues of noise for English vowel identification. The purpose of this study was to investigate whether such benefits of using temporal modulation in noise were also presented in sentence recognition. IEEE sentence recognition in quiet, stationary, and temporally modulated noise were measured for American English native (EN) listeners, Chinese-native listeners in the United States (CNU), and Chinese-native listeners in China (CNC). Results showed that in general, EN listeners outperformed the two groups of CN listeners in quiet and noise, while CNU listeners had better scores of sentence recognition than CNC listeners. Moreover, at low SNRs, the masking release on sentence recognition from the temporal modulation in noise was greatest for EN listeners, and the smallest for CNC listeners with the CNU listeners in between, while at middle and high SNRs, there was no significant group effect on the masking release, consistent with the findings of English vowel perception. The group difference in using temporal modulation of noise may be associated with acoustic differences between Chinese and English speech.
Experimental tests of protective covers to obtain optimal transmission loss in porous materials
Authors: Liu Jin , Wang John
Published: May 2015

Porous resistive materials are widely used to increase the wide-band transmission loss and reduce shell vibrations and noise propagation. For industrial applications, porous materials need to be covered to protect them from environmental contaminants. The goal of our experimental studies is to determine suitable covers which are acoustically transparent and offer this needed protection. Expansion volumes were designed for transmission loss tests with two accurate modeled limits related to two rigid boundary conditions. Seven different covers were tested in this study tests. Best results were achieved using thin porous steel woven cloth. Tyvek, Mylar, thick steel woven cloth, and the Nomex were not as effective. The porous materials and covering materials were tested and then retested after being soaked in oil to explore transmission loss that might occur in actual industrial conditions. These independent measurements of the cover materials were used to determine the material property in the FEA models.
Smoothed particle hydrodynamics approach for modeling sound of a rigid body falling on water
Authors: Zhang YongOu , Zhang Tao , Li TianYun , Wang Peng
Published: May 2015

Computational acoustic methods based on Eulerian description are widely used in industrial applications. However, some special acoustic problems, such as transient acoustic problems with moving or deformable boundaries, object separation, or for multiphase systems, are still cannot ideally solved with these Eulerian methods. The present work aims at using a Lagrangian meshfree method, the smoothed particle hydrodynamics (SPH), to simulate a time-domain acoustic problems with moving boundaries which is the sound of a rigid body falling on water. First, Lagrangian acoustic wave equations considering the sound source based on the hydrodynamic/acoustic splitting method are given and represented in the SPH form. Then, two-dimensional simulation of a rigid object falling on the free surface of water is computed by the SPH method. Noise sources are obtained from the flow field information of each fluid particle. Finally, acoustic experiments with measuring the sound of the rigid body falling on water are used to test and validate the SPH results. The accuracy and efficiency of the SPH acoustic computation are evaluated, and a comparison of cases with different impact velocities is also discussed.
Effect of low-intensity highpass noise on stimulus frequency otoacoustic emission group delays for low frequency evoking tones
Authors: Beim Jordan A. , Wojtczak Magdalena
Published: May 2015

Stimulus-frequency otoacoustic emissions (SFOAEs) have been used in previous research to estimate cochlear tuning in humans. These estimates of tuning rely on the theory that SFOAEs arise from coherent reflections from the place on the basilar membrane (BM) with the characteristic frequency (CF) of the tone evoking the emission. Theories underlying SFOAE generation are still the subject of much debate, and several recent studies have shown evidence supporting an alternative theory postulating that generators of SFOAE are distributed basally to the CF place on the BM. Basally distributed emission generators could explain why SFOAE-derived group delays measured in the chinchilla cochlea for low-frequency tones were shorter than predicted by coherent-reflection hypothesis. The aim of the current study is to look for potential effects of basal emission generators in SFOAE-derived measurements of group delay at low frequencies in humans. SFOAE group delays were measured at 0.5, 0.75 kHz with and without a low intensity highpass noise, used to perturb basally distributed emission generation sites. Results show that the presence of the highpass noise leads to increased group delays estimated from SFOAEs, consistent with the hypothesis that basal generators of emission influence estimates of cochlear group delay at low frequencies.
The influence of short term perceptual learning of pitch discrimination and modulation discrimination on subcortical envelope-following and cortical steady-state EEG responses
Authors: Lau Bonnie , Ruggles Dorea R. , Katyal Sucharit , Engel Stephen A. , Oxenham Andrew J.
Published: May 2015

Many perceptual skills improve with training, and research suggests that long- and short-term experiences modify auditory neural structures and function. Long-term cortical and subcortical plasticity has been associated with musical training and fluency in tonal languages, and short-term training effects have been regularly observed in cortical responses. Less is known about short-term subcortical plasticity, or the simultaneous relationships between subcortical and cortical responses under training conditions. The current study examines short-term learning and neural plasticity, using behavioral measures in combination with simultaneous subcortical and cortical steady-state EEG responses. Untrained, naïve subjects were randomly assigned to groups that were trained on fundamental-frequency (F0) discrimination, amplitude-modulation rate discrimination, or visual orientation discrimination. All auditory stimuli consisted of unresolved harmonic complexes with a nominal F0 of 137 Hz that were sinusoidally amplitude modulated at 100% depth and 13-Hz rate. Simultaneous subcortical envelope-following responses (EFR) to the F0 and cortical auditory steady-state responses (ASSR) to the modulation rate were measured pre- and post-training, and changes in the magnitude of phase locking to the respective frequency components were compared to changes in behavioral measures. The methods provide a new window on subcortical and cortical plasticity and their interactions. [Work supported by NIH grant R01DC05216.]
The notion of “frequency clusters” in spontaneous otoacoustic emission generation
Authors: Salerno Anthony , Bergevin Christopher
Published: May 2015

Normal, healthy ears can emit unprovoked low-level sounds called spontaneous otoacoustic emissions (SOAEs). These arise in a wide variety of different species (e.g., humans, lizards) despite gross morphological differences commonly thought important to the associated biomechanics. As such, theoretical models of SOAE generation differ significantly in their underlying assumptions. One model class [Vilfan and Duke (2008), Biophys. J. 95, 4622–4630; Wit & van Dijk, 2012 JASA 132, 918–926] uses a coupled nonlinear oscillator framework, where each element exhibits a limit cycle (with a unique characteristic frequency) and is visco-elastically coupled to its nearest neighbor. This model proposes that SOAEs arise by groups of oscillators that self-entrain into “clusters,” defined simply as the frequency where the largest peak in the steady-state spectral magnitude occurs. Our study sought to computationally explore more precisely what constitutes a cluster in terms of the underlying oscillator's dynamics. We found that oscillators within a cluster exhibit relatively complicated motions and poor phase coherence. Coupled with the model's inability to reproduce realistic SOAE spectra, the biomechanical relevance of a “cluster” is called into question. Modifications to the model for lizard ears (e.g., universal coupling via the rigid basilar membrane; Bergevin & Shera (2010), JASA 2398–2409) are explored.
Simulating the response to clicks and the generation of spontaneous otoacoustic emissions using a cochlear model
Authors: Meaud Julien
Published: May 2015

The response of the mammalian cochlea to acoustic clicks of low intensity is characterized by a long duration that includes several lobes of vibrations. Furthermore, some mammalian ears can spontaneously emit sounds, called spontaneous otoacoustic emissions (SOAEs), which are measurable in the ear canal. These phenomena are consequences of the active feedback by outer hair cells (OHCs) in the cochlea and give important information about cochlear biophysics. In this work, we use a computational model of the cochlea coupled to a lumped parameter middle ear model. Formulation of the model using a state-space approach allows determining the linear stability and the time-domain response of the model. In order to predict several lobes of vibrations in response to a click and the emission of SOAEs, inhomogeneities are introduced in the OHC properties. The model is shown to be in excellent with many aspects of the response of the cochlea to clicks that have been observed in experiments. Numerical results are used to demonstrate the strong link between characteristics of the frequency response and of the time-domain response. With small changes in the model parameters, a linearly stable model can become an oscillatory model that can emit SOAEs.
Demonstrations of fundamental topics in structural acoustics using a simply-supported plate
Authors: Barnard Andrew R. , Hambric Stephen A.
Published: May 2015

As part of the ACS 519 course, sound-structure interaction, offered through the Penn State Graduate Program in Acoustics a set of demonstrations was developed to help reinforce structural acoustics theory. A simply-supported plate was used to develop a set of four concept demonstrations: mobility functions, radiated sound directivity, fluid loading, and acoustic transmission loss. A modal impact hammer, accelerometers, microphones, a sound level meter, and a sound intensity probe were used in combination with National Instruments compact DAQ systems and LabVIEW software to develop these custom demonstrations. Basic theory and setup of the demonstrations are presented as well as videos of the demonstrations themselves.
A glass half full: Demonstrations of some surprising effects of fluid loading on the resonance of wine glasses (and other vessels)
Authors: Piacsek Andrew A.
Published: May 2015

A popular and (perhaps) provocative demonstration in an introductory course on acoustics and vibration involves asking students to predict what happens to the tap tone of a wine glass when liquid is added. Although their predictions are often incorrect, students readily accept the explanation of mass loading for why the pitch decreases, having already seen what happens to the frequency of a mass-spring system when mass is added. But is the pitch-lowering effect the same for all vibrational modes? Does it depend on the shape or thickness of the glass? For students beyond the introductory level, these questions stimulate deeper thinking about fluid-structure interaction. Predictions can be verified with a very simple apparatus.
Standing waves on an electrically heated wire, revisited: Demonstration of glow at the nodes
Authors: Korman Murray S. , McClanahan Ted
Published: May 2015

In the experiment, a nichrome wire is suspended between a metal bridge and a pulley with a weight hanger and standard weights that supply a constant tension. The 28 gauge wire has a diam = 0.32 mm and a mass/length = 0.66 g/m. For a 2 m long wire with a 0.43 kg mass providing tension, the standing wave resonant frequencies are integer multiples of 20 Hz (neglecting the wire’s stiffness). An AC current from a variable autotransformer is used to heat the wire (from the bridge to the pulley) until it glows. Near the bridge, a variable gap neodymium magnet is positioned with its poles on either side of the wire. The wire will glow at the nodes, but due to cooling (by the air vibration) the antinodes do not glow. The experiment is described in [C. A. Taylor, The Art and Science of Lecture Demonstration, Taylor & Francis, 1988]. Replace the magnet with an oscillator and audio power amplifier for frequency control [Sabatier and Drewrey, J. Acoust. Soc. Am. 104, 1793 (1998)]. One can also demonstrate glowing nodes for “standing waves in a circle,” by modifying the setup of [H. F. Meiners, Am. J. Phys. 33, xiv, Oct. 1965].
Interactions among phonetic reduction and sociolinguistic variation in word recognition
Authors: Jones Zack E. , Clopper Cynthia G.
Published: May 2015

A number of linguistic factors influence the phonetic realization of segments within a word, especially vowels within the word. These factors include lexical frequency, lexical neighborhood density, semantic predictability, and mention within a discourse. Sociolinguistic factors, such as speaking style and regional dialect, are also known to influence the phonetic realization of vowels. This study investigates the ways in which phonetic reduction caused by the linguistic factors and sociolinguistic variation from speaking style and talker dialect affect lexical processing. Participants are asked to identify single word tokens in noise that vary in frequency, density, predictability, discourse mention, speaking style, and talker dialect in a fully crossed design. We expect participants to identify words containing vowels with less phonetic reduction, a clear speaking style, and a familiar regional dialect with greater accuracy than words with more reduced vowels, a plain speaking style, or a less familiar dialect. The experimental design allows us to explore the individual contributions to word intelligibility of each of the linguistic and sociolinguistic factors independently and in complex interactions.
Talker normalization and acoustic properties both Influence spectral contrast effects in speech perception
Authors: Assgari Ashley , Stilp Christian
Published: May 2015

Talker normalization (TN) occurs when listeners adjust to a talker’s voice, resulting in faster and/or more accurate speech recognition. Several have suggested that TN contributes to spectral contrast, the perceptual magnification of changing acoustic properties. Studies using sine tones in place of speech demonstrated that talker information is not necessary to produce spectral contrast effects (Laing et al., 2012 Front. Psychol.). However, sine tones lack acoustic complexity and ecological validity, failing to address whether TN influences spectral contrast in speech. Here we investigated how talker and acoustic variability influence contrast effects. Listeners heard sentences from a single talker (1 sentence), HINT (1 talker, 200 sentences) or TIMIT databases (200 talkers, 200 sentences) followed by the target vowel (varying from “ih” to “eh” in F1). Low (100–400 Hz) or high (550–850 Hz) frequency regions were amplified ( + 20, + 5 dB) to encourage “eh” or “ih” responses, respectively. When sentences contained + 20 dB spectral peaks, contrast effect magnitudes were comparable across conditions. When sentences contained + 5 dB peaks, contrast effect magnitudes decreased overall, but were smallest following TIMIT sentences with larger, comparable effects for single-talker conditions. Thus, TN influences contrast effects when spectral peaks are modest, but not when they are large.
Speaker age effects on the voicing contrast of Tokyo Japanese stops
Authors: Jones Zack E. , Rourke Chris S.
Published: May 2015

While older Japanese speakers from the Kansai region produce voiced-voiceless stop contrasts with a true voicing distinction, older speakers from the northern Tohoku region produce the same stop contrasts with a short- versus long-lag VOT distinction, similar to the voicing contrast of English stops. However, Japanese speakers of younger generations from both of these dialect regions have been observed to produce the voiced-voiceless stop contrast in much the same way to each other, and they also seem to be using VOT as a less informative cue for stop distinction than speakers of previous generations (Takada, 2011). This study investigates the status of this sound change in the speech from the Tokyo dialect region, generally considered the standard for the modern language. Using speech data available from the Corpus of Spontaneous Japanese, we analyze stops produced by Tokyo speakers to determine differences in voicing contrast conditioned by speaker age and gender. We expect the stop contrast of older speakers to pattern differently than that of younger speakers, and we expect to see evidence for a sound change in progress similar to that observed in the other dialects. We also explore other acoustic correlates that may potentially contribute to Japanese stop contrasts as the sound change progresses.
Dialectal duration variations reveal historical sound change
Authors: Wu Di , Shih Chilin
Published: May 2015

This study models duration patterns of different dialectal regions to evaluate the spread of a phonological process. Er [ɚ] is a diminutive suffix in Chinese and is a major linguistic feature differentiating northern and southern Mandarin speech. This study evaluates the duration of the er-suffix along with its host syllable in a sentence reading task. The participants were from three regional groups chosen to examine the spread of this feature—Beijing, Mid-China, and Taiwan. Linear regression models were used to analyze duration variations quantitatively. Results reveal that Beijing speakers exhibit the most advanced er-suffixation, as expected. Duration values of words with or without the er-suffix are nearly identical, suggesting that er has been incorporated into the host syllable and has lost its own syllabic status. In contrast, speakers from Taiwan show the least advanced er-suffixation, where the suffix maintains its syllabic status with full duration. Speakers from Mid-China show an intermediate stage in accord with the geographical location. The duration contrast is consistent with reported diachronic phonological changes. The method suggests that duration patterns can be used to evaluate the spread of phonological processes, projecting synchronic, regional variations to their diachronic development.
Speaker sex discrimination performance for voiced and whispered vowels at very short durations
Authors: Smith David R.
Published: May 2015

When listening to someone’s voice what duration of stimulus is required to tell whether the person speaking is a man or a woman? Previous research studied this using voiced speech [D. R. R. Smith, Acta Psychologica 148, 81–90 (2014)]. The current study expanded this analysis by investigating what duration of stimulus is required to discriminate speaker sex when listening to whispered speech. Psychometric functions were collected plotting percent correct discrimination that a man or woman spoke, as a function of very brief vowel segment durations (up to 60 ms), for both voiced and whispered vowels. Results show that speaker sex discrimination performance is significantly impaired for whispered vowels, as compared to voiced vowels, for all durations tested. These findings are interpreted in terms of the impoverished cues to speaker sex in whispered compared to voiced speech.
Identification of talker gender and speech production mode from high-pass filtered vowel segments
Authors: Donai Jeremy , Paschall Dwayne
Published: May 2015

This study reports gender and production mode judgments from high-pass filtered vowel segments from 22 listeners with normal-hearing. Two adult males and two adult females produced vowels in an h/Vowel/d (hVd) context in both a spoken and sung mode of production. The hVd utterances were produced using the carrier phrase, “I say (insert hVd) again.” The speakers produced the sung utterances to the tune of “Old McDonald.” The vowels included /i/ as in “heed”, /ɝ/ as in “heard”, and /ɔ/ as in “hawd.” A 250 millisecond segment from the central portion was extracted and windowed. The signals were then high-pass filtered at 3.2 kHz to remove low-frequency spectral detail. The listeners were positioned in front of a graphical user interface and instructed to click on one of four buttons, “Male spoken,” “Male sung,” “Female spoken,” or “Female sung” to indicate the perceived gender and mode of production. Results showed below chance performance for the male sung and female spoken utterances and performance significantly above chance for the male spoken and female sung utterance. Signals with similar unfiltered F0 values (i.e., male sung and female spoken) were discriminated compared to those with the highest (female sung) and lowest (male spoken) F0s.
Within- and between-talker variability in voice quality in normal speaking situations
Authors: Kreiman Jody , Keating Patricia A. , Park Soo Jin , Rastifar Shaghayegh , Alwan Abeer
Published: May 2015

Increasing evidence suggests that voices are best thought of as complex auditory patterns, and that listeners perceive and remember voices with reference to a “prototype” or “average” for that talker. Little is known about how, and how much, individual talkers vary their voice quality across situations that arise in every-day speaking, so the nature and extent of variability underlying these abstract averages, and thus the nature of the averages themselves, is unclear. The theoretical relationship between acoustic similarity and confusability in the context of a prototype model also remains unclear. In this preliminary study, 9 tokens of the vowel /a/ were recorded from 5 females on three dates. Measures of F0, spectral slope, HNR, and formant frequencies and their variability were gathered for all voice samples and acoustic distances between talkers were calculated under the assumption that all acoustic variables were equally important perceptually. Perceptual confusability was assessed in a same/different task, and predictions under the equal perceptual weight assumption were tested. Discussion will focus on how much variability is required before a voice sample no longer sounds like the originating talker, and on how the perceptual importance of each acoustical variable varies across talkers and acoustic contexts. [Work supported by NSF and NIH.]
Out-of-plane effects in three-dimensional oceans
Authors: Porter Michael B.
Published: May 2015

The two-dimensional beam tracing algorithms in the BELLHOP acoustic model have been extended to three dimensions in BELLHOP3D. The new model includes virtually all of the capabilities of the 2D model, including 1) spatially varying bottom-types, 2) eigenray calculations, 3) TL calculations, and 4) time series calculations. In addition, the 3D model includes both the geometric and Gaussian beam tracing options. Finally, a simple option change allows it to switch between 2D and 3D calculations to assess the effects of horizontal refraction. This talk will discuss the algorithm, demonstrate its capabilities, and present results that illustrate when horizontal refraction is important.
Characterizing the pressure field in a modified microbubble flow cytometer: Using a laser Doppler vibrometer to validate the internal pressure
Authors: Wang Cheng-Hui , Perez Camilo , Swalwell Jarred , MacConaghy Brian , Tu Juan , Matula Thomas J.
Published: May 2015

Previously, a flow cytometer was modified with a PZT transducer in order to study the radial oscillations of statistically significant numbers of microbubbles (J. Acoust. Soc. Am. 126, 2954–2962, (2009)). We reported the results of pressure calibration for transient sonication in a recent symposium (ASA, Indianapolis, 2013). Here, we report the results of pressure calibration for steady-state sonication. Because the flow channel width (<200 μm) is too narrow to insert our hydrophones, we rely on finite element analysis (FEA) to predict the acoustic pressure field. In this study the simulation results were compared to Laser Doppler Vibrometer in-situ measurements of the velocities of the surface of the flow chamber. The OFV-534 sensor head with OFV-5000 controller (Polytec, Irvine CA) was mounted so that the laser reflected off the proximal outer surface of the flow chamber. The FEA model coupled structural vibration and linear acoustic physics to calculate the steady state pressure. The FEA model compared favorably with the LDV measurements. The FEA simulations were used to predict the pressure field, leaving only the shell elasticity and viscosity χ and κ as unknown variables in the bubble dynamics model. Excellent fits to Optison bubble oscillations were obtained.
Simultaneous measurement of sound pressure and temperature of tissue mimicking material by an optical fiber Brag grating sensor
Authors: Imade Keisuke , Koyama Daisuke , Akiyama Iwaki
Published: May 2015

An optical fiber Bragg grating (FBG) sensor is capable of simultaneous measurement of sound pressure and temperature. The FBG is a type of refractive index grating constructed in a short segment of optical single mode fiber that reflects particular wavelengths of light. This Bragg wavelength depends on both of the sound pressure and the temperature. We reported the simultaneous measurement of sound pressure and temperature in water under the conditions of medical application. In this study, temperature rise of a tissue mimicking material (TMM) caused by exposure to ultrasound in the range of 0.3 to 5 MPa were measured. The TMM is made of agar-gel with Glycerin solution of 11.21%. The FBG of 1 mm in length constructed in the optical fiber of 0.25 mm in diameter was used in the experiments. As a result, as the measured sound pressure was 5 MPa, the measured temperature rise was 6.0 degree. Thus this sensor is capable of simultaneous measurement of sound pressure and temperature rise of biological tissues exposed to the ultrasound. [This study was supported by MEXT-Supported Program for the Strategic Research Foundation at Private Universities, 2013–2017.]
Non-invasive monitoring of Achille's tendon stiffness variations in-vivo using mechanical vibrations
Authors: Salman Muhammad , Sabra Karim
Published: May 2015

A non-invasive monitoring technique of laser Doppler vibrometer (LDV) is used to find the stiffness of Achilles tendon. It is difficult for an ultrasound to collect the elastographic images of high stiffness areas such as Achilles tendon. Magnetic resonance images (MRI) technique is expensive and requires extensive training of the clinicians for elastographic image processing. This non-invasive technique needs short setup time and a simple physical structure for the data collection. A shaker is used as an excitation source, which generates waves on the tendon surface. This dynamic elastography technique measure wave velocities by an LDV. Achilles tendon is excited from 10 Hz to 1000 Hz using shaker and sensed by the LDV at four positions, which are one cm apart. Cross correlation signal processing is used for finding the time delays of the waves approaching each sensor location. It is found that as the contraction level increases, tendon stiffness increases. A comparison of average and varied stiffness values is shown in Achilles tendon. This technique may assist clinicians in characterizing muscle tone changes due to sport injuries in tendon.
Ability of skeletal muscle to protect bones and joints from external impacts: Acoustical assessment
Authors: Sarvazyan Armen , Tsyuryupa Sergey , Rudenko Oleg
Published: May 2015

One of the major (but the least studied!) functions of skeletal muscle is protecting the skeletal system from external impacts by absorbing and redistributing the energy of mechanical shock in time and space. During muscle contraction, its elasticity modulus is greatly increased, which partly unloads adjacent bones and skeletal joints. Muscle viscosity is also greatly increased helping to absorb and dissipate dangerous shocks. Elasticity and viscosity data may be obtained using the measurement of shear wave velocity and attenuation. In this study, we investigated changes in the velocity and attenuation of shear acoustic waves in an anisotropic tissue phantom mimicking skeletal muscle under different level of tension of the fibers imbedded in the phantom. Stretching the fibers simulates the muscle contraction. It is shown that both velocity and attenuation of shear waves propagating along the fibers significantly increase with fiber tension while they are negligibly affected in the case of wave propagation across the fibers. We developed a theory for propagation of shear waves in anisotropic medium simulating the muscle and muscle contraction. Equations for the speed and attenuation of various modes of shear acoustic waves are derived. Theoretical predictions are in agreement with experimental data. [NIH R21AR065024.]
Validity of acoustic method for the assessment of whole-body hydration status
Authors: Utter Alan , Calhoun Mason C. , McAnulty Steven R. , McBride Jeffrey M. , Zwetsloot Jennifer , Austin Melanie , Mehlhorn Jonathan D. , Sommerfield Lesley , Tsyuryupa Sergey , Sarvazyan Armen
Published: May 2015

In almost any sport, athletes undergoing dehydration often suffer from numerous dehydration related injuries. The purpose of this study was to evaluate the validity of acoustic method to detect changes in the hydration status of athletes after undergoing acute dehydration and a 2-hour rehydration protocol. The acoustic method of assessing body hydration status is based on the experimental fact that ultrasound speed in muscle is a linear function of the tissue water content. The assessment of water imbalance was conducted by measuring speed of ultrasound in the calf muscles using through transmission method. Eighty-two male and female collegiate athletes were examined to detect changes in hydration status before and after undergoing 3% acute dehydration. Results demonstrated that the changes of ultrasound velocity are in average about 1.1 m/s per 1% of body dehydration and ultrasound velocity in muscle potentially may serve as a measure of body hydration status. However, ultrasound speed measurement using through transmission mode implemented in this study is highly dependent on the positioning of the probe: even slight variation in the acoustic path results in significant changes in the measured values, which may results in unacceptable error. A solution to this problem is proposed and discussed. [NIH2R44AG042990.]
Design and characterization of a sensitive optical micro-machined ultrasound transducer
Authors: Leinders Suzanne M. , Westerveld Wouter J. , Pozo Jose , van Neer Paul , Urbach H. P. , de Jong Nico , Verweij Martin D.
Published: May 2015

Novel 3D intravascular or transesophageal ultrasound approaches require transducer arrays containing many small elements. Conventional piezo-electric techniques face fabrication challenges due to narrow kerfs and dense wiring. Micro-machined alternatives like CMUTs and PMUTs lack either sensitivity or bandwidth to fully compete. Therefore we developed an opto-mechanical ultrasound sensor. The absence of wiring makes it MRI compatible. The developed OMUT contains integrated photonics, which is fabricated using standard silicon-on-insulator technology, providing a small footprint and enabling mass production and ease of integration. The sensor consists of a straight waveguide and a micro-ring resonator integrated on a 124 μm wide, 2.7 μm thick acoustical membrane. Light, passing the waveguide, is partly coupled into the ring resonator. A dip appears in the spectrum of the transmitted light at the resonance wavelength of the micro-ring. If the acoustical membrane and hence the micro-ring is deformed due to an incident ultrasound wave, this is observed as a shift in the resonance wavelength of the ring. This paper presents the construction and characterization of our device. Measurement results of the linearity, frequency response, sensitivity and temperature dependence are compared with a model. The results demonstrate that our OMUT is a promising basis for future ultrasound arrays.
Lou Sutherland—Contributions in aircraft noise
Authors: Brooks Bennett M.
Published: May 2015

Lou Sutherland has made pivotal contributions to the understanding of aircraft noise and its effects and to developing solutions for those problems. His work in noise effects ranges from the 707 aircraft prototype, the development of an engine noise suppressor for the B-52 to reduce sonic structural fatigue, to the Saturn rocket program. Lou’s interests have encompassed aircraft engine turbomachinery cascade acoustic resonances and the propagation of sound through the atmosphere. These contributions were made while Lou was a researcher first at Boeing and later at Wyle Labs, as Chief Scientist and Deputy Director of Research. His insights have led to creative solutions to reduce aircraft noise effects on structures and on humans. He served as President of INCE and as an Associate Editor of JASA. In 2002 Lou was awarded the Acoustical Society of America Silver Medal in Noise “For contributions to the solution of aerospace and community noise problems, and for studies of molecular absorption and classroom acoustics.” Most importantly, Lou has a terrific, infectious enthusiasm for all that he does, which is combined with a warm, generous spirit. Lou has provided kind and gentle leadership and guidance to many grateful beneficiaries over the years.
Lou Sutherland: A friend and colleague over the years
Authors: Schomer Paul D.
Published: May 2015

I have known Lou for a short time compared to some of you, only 50 years. Over these years, our paths have crossed in many ways at many times: reviewing the US Army’s research program that I set up in 1972, development of structural response of buildings and its application to impulse noise and aircraft noise, joining with me and others in a collaborative consultative effort near the St. Louis airport, interacting with me as associate editor of JASA, and participating in Standards—notably the classroom acoustics standard.
Lou Sutherland—The man and his work
Authors: Sharp Ben H.
Published: May 2015

Lou Sutherland is one of the longest serving members of the international acoustics community and one of the most prolific. In a career lasting over 60 years, his main areas of research have involved studies of human and structural response to noise, sonic boom and blast, but his contributions to the fields of acoustics and vibration have been much more diverse and have included topics such as atmospheric absorption, aircraft noise measurement and modeling, low-frequency noise, and acoustic testing. He has been active in standards organizations and as a result of his services has been elected as a Fellow in several professional societies. As a consultant, Lou had the ability to break down complex problems into simple components that could be understood and solved, often using limited available data and simple theoretical models. Lou is still active as a consultant and continues to influence people with his ideas. As a long-term colleague, the author will examine some of his major contributions and share some of his experiences working with Lou.
Absorption of sound at high altitude: Lou Sutherland's contribution
Authors: Raspet Richard , Petculescu Andi , Godin Oleg A.
Published: May 2015

Lou Sutherland was one of the original developers of ANSI S1-26, “Method for the calculation of the absorption of sound in the atmosphere.” Research in the propagation of infrasound in support of the Comprehensive Test Ban Treaty Organization demonstrated the need for a reformulation of the calculation in the stratosphere and thermosphere. Lou and Hank Bass developed the formulation appropriate to the composition and environment of the upper atmosphere. The paper [J. Acoust. Soc. Am. 115(3), 1012–1032 (2004)] documenting this work is an impressive example of the compilation of databases and ideas into a coherent model to predict the absorption of sound. In conclusion, we will briefly review recent research extending the analysis of infrasound in the upper atmosphere.
Perceived emotional valence in clear and conversational speech for older adults with hearing loss
Authors: Morgan Shae D. , Ferguson Sarah H.
Published: May 2015

When asked to speak as though talking to an individual with hearing loss, talkers modify their speech from their everyday conversational style to a “clear” speaking style. Audiologists have observed in practice that individuals with hearing loss sometimes complain that their frequent communication partners are shouting at them, while the communication partners insist they are just trying to speak more clearly. A previous study investigated how individuals with normal hearing perceived emotional valence in clear and conversational speech and found that clear speech sounded angry more often than conversational speech. The present study will explore whether a similar effect is found in older individuals with hearing loss. Perceived anger has been partially attributed to increased energy in the high frequencies, where age-related hearing loss is most severe. Furthermore, aging effects have been found for visual emotion perception. Older adult listeners with hearing loss will be presented with conversational and clear sentences from the Ferguson Clear Speech Database (Ferguson, 2004) and asked to assign an emotion category to each sentence (anger, sadness, happiness, fear, disgust, or neutral). The results will indicate whether elderly listeners with hearing loss judge clear speech as sounding angry more often than typical conversational speech.
Performance analysis of a fuzzy soft decision CFAR detector in non-Rayleigh background
Authors: Xu Yanwei , Hou Chaohuan , Yan Shefeng , Ma Xiaochuan
Published: May 2015

A fuzzy statistical normalization fuzzy constant false alarm rate (FSN-FCFAR) detector in non-Rayleigh background based on fuzzy statistical normalization and fuzzy soft decision is proposed. The performance of the proposed fuzzy soft decision detector is studied both for homogeneous backgrounds and for non-homogeneous environments caused by interfering targets or clutter edges. Performance comparisons with the conventional hard decision CFAR detectors such as CA-CFAR, GO-CFAR and OS-CFAR are carried out. The comparison results show that the proposed FSN-FCFAR detector can not only get a very good detection performance in homogeneous backgrounds, but also can confront interfering targets and clutter edges at the same time in non-homogeneous environments. Moreover, the fuzzy soft decision detector can provide more valuable information than the hard decision detector for data fusion, target tracking or object identification.
Lucky ranging in underwater acoustic environment subject to spatial coherence loss
Authors: Ge Hongya , Kirsteins Ivars P.
Published: May 2015

In principle, a passive sonar system utilizing a long line array can estimate a source’s range by measuring its wavefront curvature. However, implementation can be difficult because wavefront curvature ranging is highly sensitive to spatial coherence losses. Real-world data measured by towed arrays often exhibit rapid fluctuations in signal spatial coherence across time and frequency. Such non-stationary degradation in spatial coherence on distributed arrays bears the similarity to the atmospheric Kolmogorov Turbulence Effect present in ground based telescopes (blurring of stars). Inspired by the lucky imaging approach used in astronomy, we propose a new approach for passive ranging in underwater environments subject to time-varying spatial coherence loss. Over short time scales, we speculate that the ocean may be well-behaved in the sense that there are little or no distortion to the signal wavefronts aka lucky moments. If detected, these lucky moments can be utilized to estimate range more accurately, overcoming coherence loss degradations experienced over long integration times. Modeling the signal as either coherent or incoherent in a short time frame, we derive the maximum likelihood lucky range estimator and show that with proper time-scale and processing bands, lucky moments can be identified that yield greatly improved estimates of range.
Comparisons between energy-flux propagation models utilizing single- and multiple-scattering treatments of sea-surface roughness in a range-independent waveguide
Authors: Schneiderwind Joseph D. , Olson Derek , Holland Charles W. , Lyons Anthony
Published: May 2015

Acoustic scattering from a rough sea surface in propagation modeling is generally treated using a single-scatter approximation in which only specular components are considered and the incoherent field is neglected. This work presents energy-flux calculations of transmission loss for a shallow water waveguide with a rough sea-surface following a Pierson-Moskowitz spectrum. Multiple scattering is evoked by considering conservation of energy from scattering events. Comparisons are made between the model with multiple scattering and that using the single-scatter approximation. Models are compared to the direct solution using the boundary element method. [This work was partially funded by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program, the Eric Walker Fellowship from the Applied Research Laboratory at the Pennsylvania State University, and the Achievement Rewards for College Scientists (ARCS) Foundation Pittsburgh Chapter.]