bluuebunny/crossref_metadata_2025 huggingface dataset:
An impedance-mobility model of stacked membrane-type acoustic metamaterials
Authors: Blevins Matthew G. , Lau Siu-Kit , Wang Lily M.
Published: May 2015

Membrane-type acoustic metamaterials have been proven to exhibit high low-frequency transmission loss despite their small thickness and light weight. To date, analysis has focused primarily on experimental studies in plane-wave tubes and numerical modeling using finite element methods. These methods are inefficient when used for applications that require iterative changes to the structure of the material. In addition, high sound transmission loss with a single layer of such metamaterial only occurs in a narrow frequency range. To facilitate design and optimization of stacked membrane-type acoustic metamaterials, a computationally efficient dynamic model based on the impedance-mobility approach is proposed. Results are verified against a finite element model. Single and double layer transmission loss characteristics are compared. Wide-band high-transmission-loss acoustic metamaterials can be achieved by double layer membranes and using the proposed approach for optimization. The impedance-mobility approach is shown to be very efficient for modeling and optimization of such materials, compared against the conventional finite element approach.
A coupled finite element/equivalent source formulation for transient structural-acoustic problems
Authors: Fahnline John B.
Published: May 2015

Recent research suggests that instability problems that occur in the time domain boundary element formulations are manifestations of nonuniqueness difficulties, and that remedies similar to those used in frequency domain formulations can address the difficulties and improve solution stability. For frequency domain equivalent source formulations, the difficulties can be addressed by combining simple and dipole sources together to form “tripole sources”. The basic goals of the current research are to develop an analogous equivalent source formulation for transient acoustic boundary value problems and to combine it with structural finite element analyses to solve transient coupled structural-acoustic problems. A brief description of the equivalent source formulation is given along with several validation cases for acoustic boundary value problems, including one with a closed boundary surface where nonexistence difficulties should occur. The formulation requires convolution summations, which are independent of each other and a brief discussion is given of how the computations can be parallelized. A brief description is also given of the coupled finite element/equivalent source formulation for transient structural-acoustic boundary value problems. Several examples are given to validate the formulation and to demonstrate that the tripole source formulation for the equivalent sources is more stable than the simple source version.
Quantal biomechanics in an embodied phonetics
Authors: Gick Bryan , Moisik Scott R.
Published: May 2015

Quantal regions were described by Stevens [e.g., 1989, J. Phon. 17, 3–45] to identify nonlinear stabilities in the relationship between articulation and acoustics. Classic cases of quantal effects show how tongue posture may vary within one region of the vocal tract with little acoustic change, while in other regions very small movements can have large effects on acoustic output. Such effects can be thought of as attractors to speech behavior in those regions of the phonetic space that allow greater noise. Quantal-like stabilities have been suggested to operate not just in articulatory-acoustic space, but in biomechanical-articulatory space as well [e.g., Schwartz et al., 1997, J. Phon. 25, 255–286]. It is argued here that such quantal-like stabilities are a hallmark of speech modules [Gick & Stavness, 2013, Front. Psych. 4, 977], providing the basis for robust, feed-forward control. Computer simulations in the ArtiSynth platform (www.artisynth.org) are used to demonstrate quantal effects in speech biomechanics at multiple vocal tract loci, including the lips, oropharyngeal isthmus, and larynx. Moving into the future, quantal work will integrate observations about nonlinear stabilities cutting across the many physical and sensory domains that figure in speech. [Research funded by NSERC.]
On the use of respiratory masks for speech measurements
Authors: Zhang Hao , Chen Xiao , Zahorian Stephen
Published: May 2015

Ideally, respiratory masks, when used to make certain measurements of speech and singing, should not interfere with what is being measured. Unfortunately this is not always the case. In this paper, two masks intended for speech measurements, are experimentally compared. One is a hard-walled mask manufactured and marketed by Kay-Pentax. The other is the circumferentially-vented pneumotachograph (CV) mask manufactured and marketed by Glottal (Syracuse, NY). Distortion measures, as quantified by formant frequencies, and muffling measures, as quantified by estimated mask transfer functions, indicate that the hard-walled mask interferes with the speech characteristics much more than does the CV mask. It is hypothesized that SPL measurements are also likely to be inaccurate if taken when using the hard-walled mask.
Improving the accuracy of speech emotion recognition using acoustic landmarks and Teager energy operator features
Authors: Asadi Reza , Fell Harriet
Published: May 2015

Affective computing can help us achieve more intelligent user interfaces by adding the ability to recognize users’ emotions. Human speech contains information about the emotional state of the speaker and can be used in emotion recognition systems. In this paper, we present a machine learning approach using acoustic features which improves the accuracy of speech emotion recognition. We used 698 speech samples from ”Emotional Prosody Speech and transcripts” corpus to train and test the classifiers. The emotions used were happy, sadness, hot anger, panic, and neutral. Mel-frequency Cepstral Coefficients (MFCC), Teager Energy Operator (TEO) features, and acoustic landmark features were extracted from speech samples. Models were trained using multinomial logistic regression, k-Nearest Neighbors(k-NN) and Support Vector Machine(SVM) classifiers. The results show that adding landmark and TEO features to MFCC features improves the accuracy of classification. SVM classifiers with a Gaussian kernel had the best performance with an average accuracy of 90.43%. We achieved significant improvement in the accuracy of the classification compared to a previous study using the same dataset.
Using the speech recognition virtual kitchen infrastructure for reproducible cross-disciplinary speech research exchange
Authors: Plummer Andrew R.
Published: May 2015

Computational models and methods of analysis have become a mainstay in speech research over the last seventy years, but the means for sharing software systems is often left to personal communication between model developers. As a result, the sharing of systems is typically complicated, error-prone, or simply not done at all, making it difficult (in some cases impossible) to verify model performance, engage with developers directly using their own models, or bridge gaps between research communities that have diverged over time. Moreover, the learning curve for new students or tech consumers entering these communities is quite steep, limiting the use of the models to those initiated in a given area. Over the last few years a number of computing infrastructures have taken shape that aim to address the difficulties encountered in the exchange of large software systems (e.g., the Berkeley Computational Environment, http://collaboratool.berkeley.edu/). We present the Speech Recognition Virtual Kitchen (www.speechkitchen.org)—a computing infrastructure that provides tools and communication channels for the exchange of speech-related software systems in a manner that facilitates the sharing of reproducible research models and pedagogical material—together with several demonstrations of the infrastructure and its potential uses.
Languages across the world are efficiently coded by the auditory system
Authors: Stilp Christian , Assgari Ashley
Published: May 2015

Independent Component Analysis (ICA) is a powerful method for uncovering statistical structure in natural stimuli. Lewicki (2002 Nature Neuroscience) used ICA to examine statistical properties of human speech. Filters that optimally encoded speech were an excellent match for frequency tuning in the cat auditory nerve, leading to suggestions that speech makes efficient use of coding properties in the mammalian auditory system. However, Lewicki only examined American English, which is neither normative nor representative of the world’s languages. Here, fourteen languages were examined (Dutch, Flemish, Greek, Javanese, Ju|’hoan, Norwegian, Swedish, Tagalog, Tahitian, Urhobo, Vietnamese, Wari’, Xhosa, and Yeyi). Each recording contained speech tokens from a native speaker without any background noise for at least one minute. Maximum likelihood ICA was used to create statistically optimal filters for encoding sounds from each language. These filters were then compared to the same physiological measures analyzed in Lewicki (2002). Languages produced a range of ICA solutions, as expected, but were highly consistent with both statistically optimal filters for American English and physiological measures. Results significantly extend Lewicki (2002) by revealing agreement between response properties of the auditory system and speech sounds from a wide range of languages.
Naval oceanography contributions to underwater acoustics—The Cold War era
Authors: Winokur Robert S.
Published: May 2015

Underwater acoustics is an integral part of the Navy and is the major enabler for its capabilities in anti-submarine warfare. The importance of oceanography to naval warfare in general and anti-submarine warfare in particular was clearly demonstrated during World War II. Anti-submarine warfare became high technology in the post World War II era, especially during the Cold War. The period from 1960 to the mid 1980s was an important time in the history and evolution of underwater acoustics, building on the experience and important discoveries and research made shortly before, during and immediately after World War II. Naval oceanography programs, large-scale measurement programs and Navy support for research and development were key elements in the rapid expansion of knowledge in the full spectrum of underwater acoustics and understanding the effect of the ocean environment on the development and operation of anti-submarine warfare systems. This paper will provide an overview of the relationship of Naval oceanography to the rapid expansion of knowledge of underwater acoustics during an important period of the Cold War era.
Pioneers in side scan sonar: Julius Hageman and the shadowgraph
Authors: Commander Kerry , Sternlicht Daniel
Published: May 2015

The concept of the side scan sonar was developed during the early 1950s at the U.S. Navy Mine Defense Laboratory, Panama City Florida—now known as the Naval Surface Warfare Center Panama City Division. In technical reports and laboratory notebooks, Dr. Julius Hageman, a German scientist who relocated to the Laboratory after World War II and worked there until his death in 1964, outlined the proposed “short-range high-definition mine location sonar” that would eventually become the C-MK-1 mine classification sonar system, more commonly known as “Shadowgraph.” Hageman’s patent for the concept (US Patent 4,197,591) was first disclosed in 1958, but remained classified until finally issued in 1980. The Shadowgraph was contracted by the U.S. Navy in 1957 and towed primarily from Oceangoing Mine Sweepers. It was operated as an undersea search and survey tool for more than 25 years before decommissioning in 1991. The Shadowgraph was a 1.5 MHz dual-sided side scan sonar, with range of 100 feet, and imaging resolution of approximately 3 in. square at a range of 75 feet. During its service life, it located numerous lost objects and aircraft on the sea floor and to this day has influenced the development of commercial and military sonars.
Early acoustics research at the Navy’s Pacific research and development laboratory
Authors: Rees C. D.
Published: May 2015

Few organizations have a more essential connection to underwater acoustics than the US Navy; the Navy’s mission success has been critically dependent on understanding and exploiting underwater acoustics since the advent of submarines. In its several manifestations since WW II, the Navy’s San Diego-based R&D laboratory (currently SPAWAR Systems Center Pacific) has played an important role in the development of the underwater acoustics field. This progress has been in conjunction with other San Diego institutions, such as Scripps Institute of Oceanography and the Marine Physics Laboratory, and other Navy laboratories. We provide a historical overview of acoustics research at SSC Pacific and predecessors in the era following WW II, including the impact of the environment, Arctic acoustics, fielded systems, sonar and active acoustics, and marine mammal acoustics, and the scientists and researchers such as Homer Bucker, Sam Ridgeway, Shelby Sullivan and others who worked in developing our modern understanding of underwater acoustics on the edge of the Pacific.
Early history of underwater acoustics research at SACLANTCEN, La Spezia, Italy
Authors: Jensen Finn B.
Published: May 2015

The SACLANT ASW Research Centre was established in 1959 to provide scientific and technical advice to the Supreme Allied Commander Atlantic (SACLANT) in the field of antisubmarine warfare and to respond to the needs of NATO nations and maritime commands. Hence, it was a NATO-sponsored research center placed in the Italian Navy compound in La Spezia, Italy, and it was internationally staffed (total about 230) with 50 rotational scientists coming from NATO nations on both sides of the Atlantic. This review covers three decades of achievements in ocean acoustics research from the foundation in 1959 to the end of the Cold War in 1989. Both basic and area-related experimental studies of propagation in deep and shallow waters, ambient noise, signal coherence, and reverberation were conducted over the years. From the early 1970s, the Centre also initiated the development of a set of high-fidelity acoustic models, which subsequently were made available to researchers within the NATO community. Finally, the Centre served as a focus for international cooperation by organizing scientific conferences and workshops on a yearly basis and by conducting multinational measurement programs in the Mediterranean, the Black Sea, and the Eastern North Atlantic from Gibraltar up to the Barents Sea.
Remembering the life and contributions of Dick Campbell, a man of many talents
Authors: Reuter Eric L.
Published: May 2015

Aside from his many technical contributions to audio and acoustics, Dick Campbell was a teacher and mentor to many, and had a diverse set of interests outside of his scientific pursuits. A horseman, pilot, sailor, marina owner, musician, tinkerer, community leader, and devoted father, he never had any trouble staying busy, even when faced with some harsh challenges. The author was a student of Dick's at Worcester Polytechnic Institute, and greatly valued his enthusiastic mentoring. This biographical presentation will include several personal anecdotes, as well as some stories and surprises collected from Dick’s family and his many friends and colleagues.
Direction of acoustic radiation force on spherical scatterers in soft tissue
Authors: Treweek Benjamin C. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: May 2015

A theory for acoustic radiation force on a viscoelastic sphere of arbitrary size in soft tissue has been reported previously for a nonaxisymmetric incident field described via spherical harmonic expansion [Ilinskii et al., POMA 19, 045004 (2013)]. At the Fall 2014 ASA meeting, the model was used to compute the radiation force on scatterers with different sizes and properties at various positions relative to the focus of an axisymmetric incident beam. For a particle located away from the focus, the model predicts a change in the direction of the axial or the transverse component of the radiation force depending on properties of both the particle and the host medium. The focus of the present contribution is this change in direction. Scatterers with various sizes and mechanical properties are considered, and small particles are found to be more prone to this phenomenon. Additionally, the reversal in direction is found to be sensitive to variations in the shear modulus of the host medium. Comparisons are made with liquid as the shear modulus of the host medium spans the range of values encountered in soft tissue. [Work supported by the ARL:UT McKinney Fellowship in Acoustics.]
Applications of acoustic radiation force for microvascular tissue engineering
Authors: Dalecki Diane , Comeau Eric S. , Hocking Denise C.
Published: May 2015

We have developed a non-invasive ultrasound-based method to spatially pattern cells within three-dimensional (3D) hydrogels, and have demonstrated translation of this technology to microvascular tissue engineering. Acoustic radiation forces associated with an ultrasound standing wave field (USWF) can rapidly organize a variety of cell types into distinct spatial patterns within 3D hydrogels. USWF-induced patterning of endothelial cells into distinct multicellular planar bands can lead to the rapid formation of complex microvessel networks throughout the volume of the collagen hydrogel. Recent efforts have focused on optimizing acoustic exposure parameters to control resultant 3D microvessel morphology, producing multilayered composite constructs with complex, physiologically relevant vascular morphologies, and developing dual ultrasound transducer systems to noninvasively direct cell patterning within injectable collagen hydrogels in situ. Engineering microvessel networks that structurally and functionally mimic native microvasculature is critical for the fabrication and survival of a broad range of bioengineered tissues, and for the fabrication of small, vascularized tissue constructs for use as realistic cost-effective in vitro models for drug discovery and testing.
A method for predicting the performance of a steelband orchestra in arbitrary environments
Authors: Chow David , Copeland Brian
Published: May 2015

One of the challenges in steelpan performance is in determining the best placement of the various instruments in an orchestra so as to achieve the level performance desired by the musical arranger. This research attempts to develop a method for analyzing the performance of the tenor steelpan in arbitrary acoustic spaces using the room acoustic modeling software, Enhanced Acoustic Simulation for Engineers (EASE). When provided with an acoustic characterization of a speaker system, particularly the magnitude and phase radiation data, and the room in which it is located, EASE can be used to predict the resulting acoustic sound-field. EASE also requires an electrical equivalent of the instrument's sound source and, through its auralization feature, allow the user to actually hear an actual performance. EASE uses a variety of reconstruction techniques, such as ray tracing and boundary element method, to provide the most accurate responses. The study will verify the approach by comparing simulation results on direct sound coverage, total SPL, Clarity (C80), Centre Time, Reverberation, and Early decay times of the instrument with real time measurements in the usual 1/3-band octave frequency resolution. Although the work focuses on the tenor steelpan, it can be easily extended to predict the performance of an entire ensemble of steelpans in any given space.
Subjective evaluation of loudness and preference for noise containing audible tones
Authors: Toepken Stephan , van de Par Steven , Weber Reinhard
Published: May 2015

Noise in living environments often contains unwanted tonal components that contribute to the unpleasant and intrusive character of a sound and usually lead to an increased annoyance. In the measurement and assessment of noise immissions after the German DIN 45681:2005-3 standard, the higher annoyance due to audible tonal components is covered by so called tone adjustments. Depending on the SNR of a tonal component within each critical band, the level of a sound can be charged with a penalty of up to 6 dB. In this study, the psychoacoustic penalty levels for sounds containing tonal components are directly determined in listening tests. The points of subjective equality (PSEs) for loudness and preference are determined using a matching procedure. The level of the test sound with tonal components is varied until it is equally loud / preferred as a tone-free reference sound that is constant in level. The level difference between test and reference sound at the PSEs is a direct measure of the penalty level. In listening tests with pure multi-tone sounds the penalty levels were found to be well above 6 dB, indicating that for these stimuli the German DIN standard is underestimating the penalty level.
Psychoacoustically based tonality model for the evaluation of noise with tonal components
Authors: Sottek Roland
Published: May 2015

For many years in various product assessments, tonality measurement procedures have been applied to identify and quantify prominent tonal components. The perception and evaluation of sound events containing such components has become increasingly important, e.g., in the field of vehicle acoustics for the assessment of tonality due to alternative drives, or in Information Technology (IT) devices due to hard disk drive noise. Additionally, many products include fans, e.g., IT devices, household appliances, and air-conditioning systems in buildings. These fans may emit prominent tonal sounds. The effective characterization of noise with tonal components is a challenge in acoustic and sound quality measurement. Existing methods for tonality calculation often show problems when applied to technical sounds where tonality perception is caused by different physical mechanisms like pure tones, multiple tones, narrowband noises, and even broadband noise showing very steep spectral slopes. To address this multitude of perceptual phenomena in a holistic approach, a new perceptually accurate tonality assessment method has been developed based on the hearing model of Sottek, evaluating the nonlinear and time-dependent specific loudness distributions of both tonal and broadband components via the autocorrelation function. The model has been validated by many listening tests. Its background and current state are presented.
Acoustic sensitivity phenomena found in people with cancer and thyroid problems
Authors: Schnitta Bonnie
Published: May 2015

Throughout my career in acoustic engineering, I have observed two interesting dynamics. Many of the people that I encountered with extreme noise sensitivity, that is easily disturbed by noise 1–2 dB above background (typically unperceivable by most), were found to be in ill health. Once I recognized this phenomena, I began to take note that there was an increase in these numbers specific to those suffering from cancer or a thyroid problem. I began to survey these individuals and most identified having been sensitive to noise long before their initial diagnosis, further developing my theory that noise sensitivity may indeed be a symptom for certain diseases, and a warning sign for early treatment. Second, those effected by ill health were specifically more bothered by lower frequency tones than those in good health. Many of these people are plagued by their noise sensitivity and describe it as a persistent nuisance that is often associated with inability to sleep with the tones present. This paper will discuss the knowledge of these facts, as well as a means to create a better healing environment in hospitals for patients that are noise sensitive.
The effect of manipulating interaural level differences on lateralization by bilateral cochlear implant users
Authors: Brown Christopher A.
Published: May 2015

Bilateral cochlear implant (BCI) users are relatively sensitive to interaural level differences (ILDs), but have been shown to be less sensitive to interaural time differences (ITDs). A proposed method for improving spatial release from masking for BCI users was recently demonstrated to do so, but was tested in only one spatial configuration: when one sound source was to the left, and the other to the right (Brown, Ear Hear. 2014). Briefly, instantaneous ITDs were measured and converted to ILDs using a linear function in which the applied ILD increased linearly with increases in the estimated ITD. Follow-up lateralization data showed that the effect of the proposed method was to hyper-lateralize sound sources, which proved effective in the configuration originally tested but may be less effective, or even deleterious, in other spatial configurations. In the current study, exponential functions are used, in which the applied ILDs are small when the ITDs are small, and increase more rapidly as the ITD moves away from midline. Results show significantly reduced RMS error in a lateralization paradigm with exponential functions.
Binaural masking-patterns with short signals
Authors: Luebken Bjoern , Yasin Ifat , Henning G B. , Verhey Jesko L.
Published: May 2015

In masking-pattern experiments, thresholds are commonly measured for a sinusoidal signal masked by a narrow-band noise as a function of the signal frequency. For a given spectral separation of signal and masker, beating between signal and masker may provide temporal fluctuation cues in addition to energy cues to detect the signal. In a dichotic condition, significantly broader masking patterns were found. It was hypothesized that this is due to the fact that the modulation cues do not play a major role in binaural processing. The present study investigates how masking patterns depend on signal duration. Masking patterns were not only measured for long (600 ms) signals but also for short signals (12 ms), where modulation cues should hardly play a role in signal detection even for monaural detection. The results show broader masking patterns for short signals than for long signals. In addition the binaural benefit does not change as much for the short signals than for the long signals when the signal frequency is varied. A binaural equalization cancellation model predicts the duration dependence of the masking patterns when a modulation analysis is assumed for the monaural pathway only.
The influence of signal type on the internal representation of a room in the auditory system
Authors: Teret Elizabeth , Braasch Jonas , Pastore M. Torben
Published: May 2015

Currently, architectural acousticians make no real distinction between a room impulse response and the auditory system’s internal representation of a room. With this lack of a good model for the auditory representation of a room, it is indirectly assumed that our internal representation of a room is independent of the sound source needed to make the room characteristics audible. In a perceptual test, we investigate the extent to which this assumption holds true. Listeners are presented with various pairs of signals (music, speech, and noise) convolved with impulse responses for different rooms. They are asked to evaluate the differences between rooms and disregard differences between the source signals. Multidimensional scaling is used to determine the extent to which the source signal influences the internal representation of the room and which room acoustical characteristics are important/perceivable for each sound type.
Just noticeable differences of listener envelopment and apparent source width
Authors: Klockgether Stefan , van de Par Steven
Published: May 2015

Listener envelopment (LEV) and apparent source width (ASW) are attributes which describe the spatial perception of a sound in a room. They are linked to several parameters of physically measurable binaural room impulse responses (BRIR), e.g., the interaural cross-correlation (IACC). Both the LEV and ASW decrease with increasing IACC. For this study the IACC of the BRIR of different rooms was directly manipulated to systematically change the spatial impression of a sound in a room. The BRIRs were convolved with anechoic music signals, and the resulting stimuli were presented to subjects in a psychoacoustic experiment to estimate the just noticeable differences of LEV and ASW. For that purpose, the subjects had to rate the different stimuli for both perceptual attributes in seven steps from “no envelopment” to “completely enveloped” or from “small” to “wide” respectively. In a second step, the stimuli which were rated the same, were used in a paired comparison paradigm to obtain a more precise estimation of the ability to distinguish between similar stimuli. The results of this study are used in a psychoacoustically motivated model to estimate differences in perceived spaciousness of sounds in rooms by the prediction of the perceived envelopment and source width.
Jacobian-Free Newton Krylov based iterative strategies in frequency-domain analyses
Authors: Cipolla Jeffrey , Nair Abilash
Published: May 2015

This study examines the theory and performance of Jacobian-Free Newton Krylov (JFNK) methods for the efficient, iterative solution of steady state dynamics of linear vibrating systems in the frequency domain. Currently, most commercial FEM algorithms employ use direct factorization of large system matrices to achieve steady state solution. Such approaches are usually quite demanding on memory and CPU requirements. Some implementations exploit iterative solutions, but still use large, assembled system matrices, requiring significant memory. The methods investigated in this work avoid the formation of a matrix completely, minimizing memory requirements and enabling much larger problems to be performed on desktop computers. Here, the Conjugate-Gradient (CG) and Transpose Free Quasi Minimal Residual (TFQMR) algorithms are studied as possibilities. These methods are of particular interest for adaptation to finite element software which uses explicit transient dynamics, because such software's optimal architecture prevents the formation and solution of a stiffness (or a tangent stiffness) matrix. In order to demonstrate the advantages of these algorithms, we choose examples that use the JFNK-CG and JFNK-TFQMR technique to show computational advantages over regular matrix based solutions, with significant decrease in memory requirements.
Random sound pressure fluctuations Induced by non-linear damping in a reactor column
Authors: Tavossi Hasson M.
Published: May 2015

Self-excited non-harmonic oscillations due to non-linear damping in the system are produced in a reactor column. The uniform steady flow is converted spontaneously into random fluctuations in sound pressure, under the especial experimental conditions, in a reactor column that includes a thin layer of dissipative porous medium. The resulting large-amplitude non-harmonic pressure fluctuations in the air-flow are similar to the bifurcation in chaotic systems; where two or more energy states can occur simultaneously, and the system oscillates between them. Experimental results demonstrate this abrupt change in flow-regime, from steady-flow to random fluctuations. Our results show that a low-pressure shock-wave- is established that precedes the self-excitation fluctuation in the system. Results also show the existence of a threshold for flow-velocity beyond which this transition from steady to pulsating non-harmonic pressure fluctuations occur. A numerical model is developed for this behavior in terms of; FFT peak frequencies, flow-velocity, characteristic numbers, relaxation-time, and system nonlinear damping.
Localized generation of a vibration pattern on a thin plate by using traveling wave control with periphery actuator array
Authors: Woo Jung-Han , Ih Jeong-Guon
Published: May 2015

Vibrations are rendered on the display panel of a mobile electronic device to transfer a tactile sensation to users for effective information. Previous vibration control has usually focused on the suppression of an entire area. The only choice for actuator position is the boundary of the panel due to the utilization of central part for other electric components by consideration of the practical application. Traveling wave control is adopted as the basic principle to generate a rendered vibration pattern. Proper weighting for both amplitude and phase for each actuator in the array is determined by applying the general inverse method with the relationship velocity responses and input signals of actuators. Experiments are conducted on a thin the tempered glass panel of a commercial tablet PC employing small moving-coil actuators. Good performance to fulfill the rendered 2x2 and 3x3 grid distribution of vibration magnitude was observed with more than 97 % success ratio. Also, Regularization provides 75% reduction of the control effort. Minimum number and optimum position of actuators for rendering target vibration pattern can be chosen by consideration of the independency of actuator array.
Looking into the future by looking back at the past: Observations about Ken Stevens’ views on speech perception
Authors: Pisoni David B.
Published: May 2015

There has always been an interest in the perception of speech and non-speech signals. As Ken pointed out 35 years ago (Stevens, 1980), speech signals possess several highly distinctive acoustic properties that set them apart from other auditory signals. He argued that the study of the acoustic properties of classes of speech sounds that occur in natural languages may provide insights about the “special” response characteristics of the auditory system. He observed that all speech sounds have a small number of general properties in common: (1) they have a short-time spectrum that contains peaks and valleys; (2) they have up-and-down variations in amplitude as a function of time; and (3) the short-time spectrum changes over time. I summarize studies with normal-hearing and hearing-impaired listeners with cochlear implants that provide converging support for the conclusion that human listeners have developed highly efficient perceptual processing strategies to make optimal use of minimal acoustic information in the speech signal. [Work supported by grants from NIDCD to Indiana University.]
Monitoring deep ocean temperatures using low-frequency ambient noise
Authors: Sabra Karim G.
Published: May 2015

In order to precisely quantify ocean’s heat capacity and ocean’s influence on climate change, it is important to accurately monitor ocean temperature variations, especially in the deep ocean (i.e., at depths ~1000 m), which cannot be easily surveyed by satellite measurements. Indeed, to date, deep ocean temperatures are most commonly measured using free-drifting oceanographic floats (e.g., ARGO floats), but this approach only provides a limited spatial and temporal resolution because of the sparseness of the existing global network of oceanographic floats. On the other hand, acoustic thermometry has already been demonstrated as an important modality for measuring ocean temperature and its heat capacity using low-frequency sound. However, current implementations of acoustic thermometry requires the use of active sources; aside from the technology issues of deploying such sources, there is also the ongoing issue of the potential disturbance of marine animals. We will demonstrate a totally passive acoustic method of acoustic thermometry based only on coherent processing of low-frequency ocean noise (f<50Hz) and whose results are in agreement with classical point measurements obtained from oceanographic floats. We will discuss how passive acoustic thermometry could improve global monitoring of deep ocean temperature variations through implementation using a global network of hydrophone arrays.
A spatially explicit estimate of environmental noise exposure in the contiguous United States
Authors: Mennitt Daniel , Fristrup Kurt , Nelson Lisa
Published: May 2015

Environmental noise is widespread across the United States, the spatial patterns of which are dependent on a complex linkage of environmental and socioeconomic factors. Chronic exposure brings with it adverse consequences to terrestrial organisms; effects on human health and wellbeing include hypertension, cardiovascular disease, sleep disturbance, cognitive impairment, and annoyance. Assessments of noise exposure are essential to understand the extent of impact as well as inform land use planning and noise abatement strategies. Using extensive empirical data and a geospatial framework, we modeled the day-night average sound level (Ldn). The dominant factors driving sound levels are land use, climate, population, and proximity to traffic corridors. Model predictions were mapped to reveal the spatial distribution of expected sound pressure levels across the contiguous United States at a resolution of 270 m. The expected Ldn was compared with localized population density to estimate the number of inhabitants exposed to levels that put them at increased risk for non-auditory health effects. The magnitude and extent of noise exposure suggests a substantial opportunity to enact measures that will improve the quality of life for many Americans.
Modeling of acoustic resonators and resonator arrays for use in passive noise control
Authors: Calton Matthew F. , Sommerfeldt Scott D.
Published: May 2015

Acoustic resonators, such as the Helmholtz and quarter-wave resonator, can be used to attenuate unwanted noise in a space. Classic formulations can be used to approximate resonator performance for a given resonator configuration, but may lack sufficient accuracy for some applications. This research aims to improve the analytical characterization of resonators to provide better correlation to experimental results. Using higher order approximations and proper end corrections, more accuracy can be obtained in calculating the impedance and resonance frequency of a single resonator, which will then carry over into the overall configuration of the model. The impedance of a system of resonators in parallel is also considered, where the effects of acoustic coupling can be observed. Resonators with complex, non-ideal geometries are explored for applications where space is limited.
Vibration analysis of damped stiffened beams and plates by complex modes and frequencies
Authors: Rosenhouse Giora -.
Published: May 2015

Stiffened beams and plates are used in design of structures forced by machinery excitation, which result in flexural motion having distorted normal modes due to the effect of both stiffeners and damping. Such plates and beams are often damped externally or internally, which leads in turn to complex modes and natural frequencies. The modes, which are normal to the direction or axis of the stiffeners can be calculated by different techniques, such as the “three moments” method for stiffened plates or beams. The effect of the stiffeners is given by finding the changes in frequencies and normal modes as related to the ratio of the stiffeners'- and plate's or beam's rigidities. The paper gives insight into complex modes and the eigenvalue for each such mode and also their relation to the common definition of modal shapes magnitude and frequencies and concludes with solved examples for stiffened plates and beams models.
Acoustical Society of America R. Bruce Lindsay Award: Matthew W. Urban
Authors: Geenleaf James F.
Published: May 2015

The R. Bruce Lindsay Award (formerly the Biennial Award) is presented in the Spring to a member of the Society who is under 35 years of age on 1 January of the year of the Award and who, during a period of two or more years immediately preceding the award, has been active in the affairs of the Society and has contributed substantially, through published papers, to the advancement of theoretical or applied acoustics, or both. The award was presented biennially until 1986. It is now an annual award.
Architectural acoustics illustrated
Authors: Ermann Michael
Published: May 2015

Novel discoveries, non-obvious findings, and counter-intuitive conclusions will be excerpted and highlighted from the just-released book Architectural Acoustics Illustrated (authored by the presenter, Wiley, 2015). The text filters the content of architectural acoustics through the graphic and built language of architecture. In writing the book, building material choices, spatial relationships, best-practices, and data were explored through drawing and animated videos. Summaries of the findings will be demonstrated graphically to establish relationships in sound absorption, room acoustics, sound isolation, and noise control.
Continuing research endeavor in room acoustic effects on speech communication and psychoacoustics
Authors: Peng Z. Ellen
Published: May 2015

I received the best student paper award in architectural acoustics at the San Francisco ASA meeting in 2013. I presented the first half of my dissertation project on designing acoustics for linguistically diverse classrooms by investigating the effect of room acoustics on speech comprehension by native and non-native English-speaking listeners. In the following year, I continued to complete my dissertation and received my PhD in architectural engineering from the University of Nebraska-Lincoln. Beginning in 2015, I am a postdoctoral fellow at RWTH Aachen University in Germany as part of the iCARE (icareitn.eu) research program funded by a Marie-Curie Initial Training Network (ITN) grant from the European Union. My role is to help improve an existing electronic system in extending its application of virtual acoustics testing on children with hearing impairment. Upon receiving the best student paper award, I continue to enjoy multidisciplinary research that combines architectural acoustics, speech communication, and psychoacoustics.
Measurement of cardiovascular tissue stiffness with acoustic radiation force
Authors: Trahey Gregg
Published: May 2015

We have developed qualitative and quantitative methods of imaging the stiffness of myocardial and vascular tissues using acoustic radiation force. In ongoing animal and clinical studies, these methods have been utilized to differentiate vulnerable from stable vascular plaques, to monitor the formation of radio-frequency- and cryo-ablation lesions, and to assess the impact of ischemia, infarct, pre-load, afterload, and coronary artery pressure on cardiac stiffness. We present alternative pulse-sequencing techniques and image reconstruction methods and discuss their impact on image contrast and resolution. We discuss the relevance of these methods in assessing cardiovascular disease and the technical challenges of introducing them into clinical practice.
Compensating for Scholte waves in single track location shearwave elasticity imaging
Authors: Langdon Jonathan , Mercado Karla , Dalecki Diane , McAleavey Stephen
Published: May 2015

The estimation of shearwave velocity in biological tissues using Single Track Location Shearwave Elasticity Imaging (STL-SWEI) depends on the assumption that the ultrasonically observed particle displacements are due to the propagation of shearwaves in an approximately infinite space. When this assumption is violated, erroneous estimates of the shearwave speed may occur leading to image artifacts. One particularly troubling error occurs when slowly propagating Scholte waves are generated at solid-fluid interfaces. These interface waves travel at a slower speed than the shearwaves produced in STL-SWEI. However, the signals produced appear similar to that of shearwaves and cannot be readily distinguished in the typical STL-SWEI imaging sequence. Instead, alternative sequences are needed to identify and correct for these anomalous wave types. In this work, the surface wave phenomena is examined in the context of STL-SWEI imaging. The appearance of these waves is demonstrated in simulation, tissue mimicking phantoms, engineered tissues, and in liver tissue using a clinical scanner. The effect of the ultrasound beam geometry on the Scholte wave measurement is studied. Finally, a revised STL-SWEI reconstruction method utilizing Radon Sums is presented. Using this method, the simultaneous characterization of shear and Scholte waves is demonstrated for the above materials.
Twitter's not just for teenagers: A scientists' guide to getting started with Twitter in just 5 minutes a day
Authors: Kloepper Laura
Published: May 2015

Twitter is an effective, powerful tool for scientists looking to keep abreast of trends in their field, communicate their research, and act as public advocates of science. With a simple 140-character Tweet, a person can announce new publications, comment on current events, share photos and updates of research, connect with budding young scientists, and more. Many people think that using Twitter is a massive time investment, but many basic Twitter activities can be conducted in the time it takes you to drink your morning coffee. This talk will introduce the basics of Twitter, show the power of Twitter, and demonstrate best practices for using Twitter with science—all in just 5 minutes a day.
Some pitfalls to be avoided in a wind turbine noise research program
Authors: Schomer Paul D.
Published: May 2015

The Acoustical Society of America has created a public policy position relative to the acoustic emissions from wind turbines. This position calls for research that definitively will show if problems exist, and if so, who is affected, how are they affected, and why. Much of the research to date is based on assumptions, frequently contrary to fact or unproven. That is not the kind of research that the ASA desires. The money spent on this questionable research should have been directed towards definitive research such as that envisioned by ASA. This paper talks about some of the previous research and elucidates on their assumptions with the purpose of preventing mistaken test designs like these in the future, and with the purpose of improving the research program to be developed by ASA.
Do wind turbines cause adverse heat effects? A review of the evidence
Authors: McMurtry Robert Y.
Published: May 2015

There is a continuing debate about the veracity of AHE in the environs of WT. Proponents claim there is insufficient evidence to support the existence of direct AHE and therefore WT are safe to erect near human habitation. The international regulations governing WT placement are highly variable but generally a setback of at least 350 m (WHO 500m) and a noise limit of 40 dBA are recommended. Nonetheless there is mounting evidence that AHE are in fact occurring. In the 1980s, N D Kelley produced evidence of direct causation of AHE, especially sleep disturbance, from downwind WT, which was attributable to impulsive infrasound and low frequency noise. Subsequently, there has emerged further evidence regarding upwind WT that satisfies the nine Bradford Hill criteria. The presentation will define AHE and address each Braford Hill criterion.
Why are regulators, communities, neighbors, and acousticians annoyed by wind turbines?
Authors: Ambrose Stephen E. , Rand Robert W.
Published: May 2015

Noise assessments for large wind turbines should be more reliable based on decades of human-response research. Empirical data clearly show the most severe noise impacts occur in the quieter environments. Populations living in quiet areas were the least researched until the arrival of wind turbines. European studies reveal that the public has a greater sensitivity to wind-turbine noise than transportation sounds. Acoustic researchers developed the percent highly annoyed metric to model. This metric should be shaped by an assessment of the acoustic environment using many variables all subjective, debatable, and mathematical. A review of dose-response research will attempt to lay the groundwork for a new noise assessment methodology specific to wind turbines.