bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracting accent information in noise-vocoded speech in Japanese
Authors: Sugiyama Yukiko
Published: October 2015

This paper gives a preliminary report of a study that examined the perception of Japanese accent in noise-vocoded speech, where spectral information is substantially compromised while keeping the amplitude envelope intact. While the F0 is known to be the primary cue for accent in Japanese, it is not certain if secondary cues exist. Acoustic analyses conducted in previous studies show mixed results in this regard. The present study attempts to find non-F0 correlates of Japanese accent by conducting a perception study that used noise-vocoded speech. Twelve native speakers of Tokyo Japanese heard ten minimal pairs of final-accented and unaccented words (e.g., /hana*/ “flower” when accented vs. /hana/ “nose” when unaccented) embedded in a carrier sentence. The results obtained so far show that the listeners’ accuracy exceeded chance level, suggesting that some acoustic information in the stimuli was present for the listeners to identify words. At the same time, relatively large individual differences were observed in their performance, indicating that some listeners were better at eliciting accent information than others. Implications of the results for the nature of Japanese accent and the perception of accent will be discussed.
A comparison of speech enhancement methods to extract Lombard speech in an external noise field
Authors: Vaziri Ghazaleh , Giguère Christian , Dajani Hilmi , Ellaham Nicolas
Published: October 2015

The tendency of talkers to increase their vocal effort in noise, known as the Lombard effect, depends on many factors including the type and level of noise. To investigate the influence of these different factors while wearing hearing protectors, the Lombard effect needs to be elicited by an external noise field (e.g., loudspeakers) rather than the traditional method (e.g., headphones). While the Lombard speech produced may be contaminated by the eliciting noise, the alterations in the talker's voice are more realistically accounted for by such methodology. The problem of recovering sound-field elicited Lombard speech has not been studied extensively. In this study, two noise suppression techniques, direct waveform subtraction and adaptive filtering, are used to recover the Lombard speech produced in simulated conditions using a manikin. To assess the performance of the two methods, the size of noise reduction is compared and basic speech characteristics (e.g., pitch and energy) and objective quality and intelligibility measures (e.g., SII and STI) are extracted from the clean and enhanced Lombard speech. Preliminary results show that the simulated Lombard speech could be accurately recovered, which is useful to extend to speech production in noise with real talkers.
Underwater Acoustics in 1950 and 1972
Authors: Bradley David L.
Published: October 2015

The National Academy (National Research Council) published “A Survey Report on Basic Problems of Underwater Acoustics Research” in 1950 and the Acoustical Society of America, in 1972, published a series of papers that were a 20-year review of various aspects of underwater acoustics. Between the two references, they provide a background of accomplishments and the perspective of scientists at that time, of the major issues in underwater acoustics. This paper is a summary of that information, and provides an “introduction” to the next 5 decades of research that is the focus of this special session. Though not the intent, a comparison of the research accomplished in later years with the proposed effort will provide a basis for further discussion.
ONR arctic acoustics 1978—1998
Authors: Baggeroer Arthur B. , Mikhalevsky Peter N.
Published: October 2015

The Arctic Program Office of the Office of Naval Research ten Arctic field programs from 1978–1994 under the visionary leadership of program managers Dr. G. Leonard Johnson and Dr. Tom Curtin. During this period, over ten ice camps in both the western Arctic (Beaufort Sea) and the eastern Arctic (Nansen and Pole Abyssal Plains were manned and four ice breakers served as platforms in the marginal ice zone (Fram Straits). Since the cost of the support logistics for Arctic field programs is so very high, these experiments were multidisciplinary and almost all had an acoustic component. Some of the highlights were transoceanic reverberation, seismic reflection and refraction, random channels for time and Doppler spreading, target detection, matched field processing,ocean acoustic tomography, seismicity, and ambient noise were among the many topics examined. There were also robust efforts advancing data acquisition. Large, two dimensional horizontal arrays with both cabled and “WIFI” telemetry, large vertical arrays, precision sensor navigation, and sophisticated remote instrumentation buoys were deployed. With the end of the “Cold War” the last field program was in 1994 and the ONR Arctic program eventually was disestablished. Now, the retreat Arctic ice cover and Arctic Ocean warming has reinvigorated ONR's interest in the Arctic and after two decades ONR field programs are planned for the near future.
In vivo cavitation thresholds and injury observations related to burst wave lithotripsy
Authors: Kreider Wayne , Maxwell Adam D. , Cunitz Bryan W. , Wang Yak-Nam , Lee Donghoon , Sorensen Mathew D. , Harper Jonathan D. , Sapozhnikov Oleg A. , Khokhlova Vera A. , Bailey Michael R.
Published: October 2015

Burst wave lithotripsy (BWL) is a new non-invasive approach for treating kidney stones that uses short bursts of ultrasound at low duty factors. An important difference between BWL and SWL relates to the potential for generating cavitation in the kidney that could cause injury. To study such cavitation behavior, 17 pig kidneys were exposed in vivo to BWL treatments of different amplitudes at frequencies of 170 and 335 kHz. Treatments lasted at least 10 min and were monitored in real time using ultrasound imaging (including B-mode and Doppler modalities) to determine threshold pressures for the onset of cavitation. After treatment, eight of the kidneys were perfusion fixed and scanned using MR imaging sequences designed to detect hemorrhagic injury. Results suggest that pressure thresholds exist below which cavitation detected by ultrasound imaging is very unlikely to occur; moreover, MR images indicate no injury or only minimal injury when cavitation was not detected. Observations at 170 kHz show a repeatable threshold pressure near 5 MPa; data at 335 kHz were less consistent butsuggest a higher threshold between 6 and 8 MPa. [Funding support by NIH NIDDK P01-DK043881, R01-DK092197, T32-DK007779, K01-DK104854, R01-EB007643, R01-CA188654, and NSBRI through NASA NCC 9-58.]
Effects of speaking style and context on online word recognition in adverse listening conditions
Authors: van der Feest Suzanne V. , Moses Samantha , Clark Amanda , Parsons Danielle , Smiljanic Rajka
Published: October 2015

This study investigated the time-course of word recognition in adverse listening conditions. Specifically, we examined the effect of different listener-oriented speaking styles and semantic context on lexical access in quiet and in noise. Young adult listeners participated in an online visual word recognition experiment. They heard sentences with a high- versus low-predictability semantic context, produced in Conversational (CO), Infant-Directed (IDS), and Clear (CS) speech while fixating two pictures on a screen: a target that matched the last word of the auditory stimulus and a distractor. All sentences were presented either in quiet, or mixed with speech-shaped noise at a −5 dB SNR. Results showed that IDS provided similar perceptual benefits to adult listeners as CS. Relative to low-predictability CO baseline, IDS and CS increased speed of word recognition for high-predictability sentences, in quiet and in noise equally. However, in the quiet condition, lexical access was eventually facilitated by contextual cues even in CO, but listeners in noise reliably focused the target only when a combination of contextual cues and exaggerated acoustic-phonetic cues was available. These findings suggest that both semantic cues and listener-oriented acoustic enhancements are needed for reliable and rapid lexical access, especially in adverse conditions.
Auditory temporal resolving power in birds
Authors: Dooling Robert
Published: October 2015

There has long been the notion that bird song contains acoustic features, which are inaccessible to human listeners. Field and laboratory studies suggest that birds hear both the spectral and gross temporal features of bird song much like we do. But how precisely birds perceive their auditory world still remains somewhat of a mystery. Here, I review psychophysical studies that provide evidence that birds have an exquisite sensitivity to temporal fine structure in their vocalizations putting some aspects of bird vocalizations out of reach of human hearing. Work with zebra finches, in particular, shows that these birds are capable of discriminating between positive and negative Schroeder harmonic complexes at high fundamental frequencies. These birds can also discriminate temporal fine structure changes in their vocal signals that are well below human thresholds. Whether this ability is used for communication is still not clear but it could underlie the better-than-expected ability of birds to localize sound and to assess the effects sound degradation and reverberation as a complex sound travels through the natural environment.
What does Da Vinci have to do with it?
Authors: Bloomfield Laurie L.
Published: October 2015

It may seem unusual to suggest a relationship between Leonardo Da Vinci (1452–1519) and the study of avian communication, as he is perhaps better known for his attempts at developing a theory of human flight based on the principles of avian flight. His approach, however, was that “from the study of structure comes the knowledge of function.” Here, I present how an understanding of the structure of the various vocalizations produced by chickadees may lend to an understanding of the function of these vocalizations. Chickadees are an excellent model system for this type of research given that they produce various calls that are comprised of individual units that may function in different ways. We have conducted several bioacoustics analyses in the search for similarities and differences among call structures, as well as attempted to delineate the bioacoustical markers that would provide meaningful information to listeners. Further, I will discuss what constitutes human “language” and how the calls of chickadees may satisfy the criteria for a non-human language. With this in mind, we use various field and laboratory techniques in an attempt to understand the structure of vocalizations which may in turn convey information regarding the function of the vocalizations.
Laboratory measurements of compressional and shear wave properties in reconstituted mud and comparison to marine sediment acoustic propagation models
Authors: Lee Kevin M. , Ballard Megan S. , Muir Thomas G. , Venegas Gabriel R. , Wilson Preston S.
Published: October 2015

Laboratory measurements were performed to characterize propagation of compressional and shear waves in mud, whose composition differs significantly from granular marine sediments like sand or silt. Muddy sediments are colloidal suspensions of thin, irregularly shaped platelets that carry surface charges linked to their cation exchange capacities. These suspensions result in flocculent structures, which cause mud to have high porosity and exhibit gel-like behavior. Samples of reconstituted mud were prepared by mixing kaolinite powder with distilled water and then placing them under vacuum to remove air bubbles entrained by the mixing process. Pairs of hydrophones and benders elements were immersed in the samples to measure compressional (50 kHz to 500 kHz) and shear (0.1 kHz to 1.5 kHz) wave speed and attenuation, respectively. A resonator tube technique was used to infer compressional wave speed at lower frequencies (1 kHz to 10 kHz). Wet-dry mass measurements characterized the density and porosity of different mud samples, and electron microscopy was used to estimate platelet size distributions. The measured material parameters were used as inputs to various sediment acoustic propagation models. The comparison between the predicted and measured wave speeds and attenuations will be described. [Work supported by ARL:UT and ONR.]
Maximum bow force revisited for the cello—Instrumentation with a precision pendulum
Authors: Mores Robert
Published: October 2015

Schelleng (1971), Askenfelt (1989), Schumacher (1993), and Schoonderwaldt et al. (2008) formulated—in slightly different ways—how the maximum bow force relates to bow velocity, bow-bridge distance, string impedance, and friction coefficients. Related measurements at the respective transitions between Helmholtz und bifurcation regimes cover a diverse scenario of bowing machines and stringed instruments. So far, the empirical data does not clearly support either of the theories in a general way. A bowing pendulum of virtually infinite radius has been constructed to allow precise measurement of relevant bowing parameters. Two cellos are measured across all strings for three different bow-bridge distances. The empirical data suggest that linear relations predict the maximum bow force sufficiently well and a more distinct general model can be drawn. Furthermore, the pendulum employs an adaptive bow driving mechanism instead of a motor or engine. Such adaptive bowing discloses that mentioned regimes are stable and transitions between them sometimes require a hysteresis on force and speed variations. This explains some of the uncertainties in earlier studies and in this study. To confirm the findings the friction coefficients are measured separately by means of the same pendulum construction.
Temporal phase evaluation of transients in the Brazilian cuíca drum
Authors: Statsenko Tatiana , Kausel Wilfried
Published: October 2015

Transient deformations can be observed by means of time-resolved electronic speckle pattern interferometry (trESPI), which implements a high-speed camera in the experimental setup and allows measurements of non-reproducible transients in real time. The stick-slip phenomena in musical instruments leads to transient nonlinear effects in the surface deformation, which can be resolved and characterized using trESPI. In this work, transient effects during the stick-slip motion of the Brazilian cuíca drum are investigated. Measurements of the cuíca under harmonic excitation and in playing conditions using trESPI are presented leading to a quantitative analysis of the motion.
How should we move forward with the next version of the ANSI S3.4 loudness standard?
Authors: Davies Patricia
Published: October 2015

Recent updates to the international loudness standard ISO 532 reflect both increased understanding of loudness and the use of loudness standards by the acoustics and engineering communities. Both are inspiration to consider revising ANSI S3.4-2007. The current ANSI standard is based on Moore and Glasberg’s model of loudness for stationary sounds. The new ISO 532-2 is a revision of this. The new ISO 532-1 is based on Zwicker’s time-varying loudness, and will replace the current ISO 532B, also based on Zwicker’s loudness model but for stationary sounds. For people who are not developing loudness models but are using them to assess sounds or noise, there are a number of other issues, e.g., loudness of very low frequency sounds, and exposure assessment based on loudness. These will be discussed and possible directions in updating the current ANSI standard are presented.
Status quo of standardizing loudness of time-varying sounds
Authors: Sottek Roland
Published: October 2015

Recently, a new ISO standard for loudness of arbitrary sounds ISO 532-1 (Zwicker method) was proposed for the revision of ISO 532:1975 (method B). The new standard is based on DIN 45631/A1:2010, which includes the widely used standard DIN 45631:1991 for stationary sounds as a special case. DIN 45631:1991 differs slightly from ISO 532:1975 (method B) by specifying corrections for low frequencies and by restricting the description of the approach to numerical instructions only, thus allowing a unique software description. ISO 532-1 eliminates uncertainties of existing standards by strictly defining the complete procedure of loudness calculation starting with the waveform of the time signal and ending with specific and total loudness vs. time functions. The strict definition of the complete procedure, given not only by formulae and tables but also by program code, is a step forward to comparability of calculated loudness results. ISO 532-1 shall update the previous ISO 532:1975 (method B) and adapt it to proven new practice while preserving procedural and database continuity. The method according to Moore/Glasberg based on the American standard ANSI S3.4-2007, for stationary sounds only, shall replace ISO 532:1975 (method A) and will be named as ISO 532-2 in the updated version.
Comparison of measured and predicted statistical measures in military jet noise propagation
Authors: Reichman Brent O. , Wall Alan T. , Gee Kent L. , Neilsen Tracianne B.
Published: October 2015

Crackle, an annoying component of jet noise, has been associated with acoustic shocks that form as a waveform experiences nonlinear steepening. The skewness of the first time derivative of the pressure waveform, or derivative skewness, is a metric that is sensitive to acoustic shocks, and has shown that shocks, and therefore crackle, are found in the far field of full-scale military jets. Recent extensive measurements on F-35 aircraft enable a comparison of linear and nonlinear predictions and measured waveforms over a large spatial area. Waveforms measured at 76.2 m from the aircraft are numerically propagated using linear and nonlinear methods to several distances up to 305 m, and the derivative skewness calculations from these numerically propagated waveforms are compared with those of measured signals. Comparisons are made for both the A and B variants of the F-35, in changing meteorological conditions, and with engine conditions ranging from intermediate power to full afterburner. [Work supported by USAFRL through ORISE.]
Speech perception and production in sequential bilingual children: A longitudinal study
Authors: McCarthy Kathleen
Published: October 2015

The majority of bilingual speech development research has focused on children who acquire both languages simultaneously from birth. Yet, for many bilingual children growing up in dense immigrant communities, their language experience is typically very different. These children, often referred to as sequential bilinguals, are initially exposed to their heritage language (L1) and in many cases are only immersed in the host country’s language (L2) when they start school at around 4-years-old. To date, little is known about the developmental trajectory of sequential bilinguals. The current study tracked the acquisition of the English voicing contrast and monophthongal vowels by Sylheti-English sequential bilingual children from the London-Bengali community. Children were tested during preschool (mean age: 54 months old) and again one year later. The sequential bilinguals perception and production was initially driven by their L1 experience, resulting in less refined English phonemic categories than their monolingual peers. With L2 experience, children acquired the target phonemic contrasts, however they displayed a preference Sylheti phonotactics in a non-word repetition task. These findings have implications for our understanding of language development in complex multilingual settings, and will be discussed in light of the children’s language input and broader phonological development.
Cognitive and linguistic influences on speech motor development
Authors: Nip Ignatius
Published: October 2015

Speech development is affected by the interaction of the development of various domains, including motor control and language. Infants demonstrate strong associations between speed and range of movement of the lips and jaw with cognitive (attention, memory) and language (number of words understood/expressed, number of gestures used) skills during language acquisition (Nip et al., 2011). In addition, goal-directed vocal behaviors (e.g., words) are produced with faster lip and jaw speeds in infants (Nip et al., 2009). Similar task-related changes can be observed in older children. Tasks requiring greater language formulation demands (e.g., re-telling stories) are produced with greater movement speeds and oral excursions than tasks requiring fewer demands (e.g., repeating syllables) (Nip & Green, 2013). Kinematic descriptions of speech production may provide insight into the acoustic consequences of adapting movement strategies for different tasks; increasing oral excursions may be a strategy to increase articulatory precision and may account for the reduced speaking rate during speaking tasks requiring greater demands (Nip & Green, 2013). In addition, coordination of articulatory movements is highly associated with intelligibility in children with and without speech disorders (Nip, in press). Understanding the interactions among motor control and language may explain patterns of speech development.
A traditional forward scattering theory view of shallow water acoustics
Authors: Duda Timothy F.
Published: October 2015

Theories of propagation through a random medium (forward scattering theories) identify the scales of feature structure within the medium that are most effective at creating field fluctuations. These scales are near the Fresnel scale for straight-line and refracted propagation. The Fresnel scale (or Fresnel radius), the square root of the wavelength times the propagated distance, is therefore useful as a diagnostic. Shallow-water propagation of sound below 1 kHz often shows a dispersed modal propagation character, with modes having distinct wavelengths. Consideration of individual modes reduces the problem physical dimension by one. Waveguide anomaly features that are known to cause fluctuations, such as small-scale internal waves and frontal intrusions, have characteristic scales that overlap with the Fresnel scales for frequencies in the range of 0.1 to 1 kHz and distances of 1.0 to 25 km (40 to 600 m). This means that established theories can be applied, as long as other requirements are met. The waveguide thickness (water depth) can also exhibit variability on these scales, causing a similar fluctuation effect, although in this case the fluctuation represents a departure from acoustic behavior with a simple planar seabed model. This scaling analysis is potentially most useful for modeling shallow-water ocean propagation, or for processing ocean data to emphasize features relevant to acoustic scattering.
Coherent, very high frequency underwater acoustic communications under wind-driven seas: Experiments in an ocean simulator
Authors: Preisig James , Deane Grant
Published: October 2015

Very high frequency, underwater water acoustic communications (VHF UWAC) operated near the sea surface are subject to interference from surface-scattered energy and, under wind driven seas, noise from breaking waves. Here, we present results from experiments to study these effects conducted in an ocean simulator. Acoustic transmissions in the frequency range (400–750) kHz were made using vertical arrays of transducers in the 44 m long, 2.4 m wide, and 1.5 m deep wind-wave channel at the Hydraulics Laboratory at Scripps Institution of Oceanography. This facility simulates oceanic conditions with a piston wave maker and a fan driving airflows up to 15 m/s. A variety of communications and probe signals were sent under calm and wind-driven conditions. Surface scattering was characterized in terms of arrival delay and gravity wave focusing, along with measurements of breaking wave noise. These data will be discussed in terms of VHF UWAC performance.
Finite element modeling of propagation and reverberation shallow water waveguide with a variable environment
Authors: Isakson Marcia J. , Chotiros Nicholas P. , Piper James
Published: October 2015

Shallow water waveguides can exhibit environmental variability in the water column, on the bottom interface and in the sediment. Finite element models provide a method to capture the effects of this variability since every element can be described by a different sound speed and density. However, fully three-dimensional finite element models are often computationally inaccessible due to extreme memory requirements. In this study, a longitudinally invariant finite element model is used to predict the reverberation from a shallow water waveguide described by environmental measurements at the Target and Reverberation Experiment 2013 conducted off the coast of the Florida panhandle. Longitudinally invariant models retain all of the fidelity of a three-dimensional model with the requirement that one geometric dimension must be invariant. Therefore, it is an ideal model for wedges and ridges. In this case, the longitudinally invariant direction describes the sand ripples. The reverberation with and without variations in sediment sound speed and density will be compared for the same bathymetry to determine the role of sediment variability in reverberation. Reverberation from along and across the sand ridges will also be examined. [Work supported by ONR, Ocean Acoustics.]
Initial considerations on effects of braided river beds on long-range acoustic propagation in shallow water
Authors: Holland Charles W. , Lowrie Allen , Hamiter Rhett
Published: October 2015

A braided river consists of multiple small channels that divide and recombine numerous times. They form when the sediment load and transporting energies are such that coarser sediment can be deposited as shifting islands or bars between the channels. Braided rivers formed on continental shelves during sea level lowstands during the last 700,000 years when the shelf was sub-aerially exposed to greater than 125 m below present day sea level. A salient feature is that the stream bed (which can be many kilometers wide) is expected to exhibit extremely high geoacoustic variability, given that the islands and bars exhibit much coarser material than that in the channels. The variability is expected both laterally (highest variability or smallest scales perpendicular to the stream flow) and also vertically inasmuch as the river channels experience different avulsion patterns over time. Chirp sonar and core data provide some insight into the underlying geologic processes and the associated scales of variability. Modeling gives some initial clues about the effects of braided river beds on acoustic propagation. [Work supported by the Naval Oceanographic Office and the Office of Naval Research, Ocean Acoustics program.]
Innovative approaches to structure borne vibration reduction
Authors: Schnitta Bonnie
Published: October 2015

People feel vibrations depending mostly on the vibration direction. One has to distinguish between vertical vibration and horizontal vibration, the latter often called lateral vibration, in order to address the homeowners’ concerns. The difference in perception is described in ISO 8041:2005. Above 20 Hz and up to 1000 Hz, vibration may be called structure-borne noise. Such vibrations may generate audible sound. In private or multi-family residence, structure-borne noise can become prevalent due to elevators, mechanical equipment, subways, nearby train tracks, etc. Often times, areas exhibiting these problems do not have the space in floor or wall configurations in order to take a traditional approach toward the abatement of this structure-borne noise. The purpose of this paper is to present the results from a controlled experiment of different combinations of floor and wall configurations under both horizontal and lateral vibration in order to simulate vibration found in the field due causing structure-borne noise. Floor and/or wall configurations will include combinations of various resilient layers in order to present configurations to successfully abate vibrations originating from these sources while conserving and minimizing space in floor and/or wall configurations to optimize the acoustic efficacy of the installation.
Acoustic comfort in closed rooms often means expectations of speech privacy
Authors: Good Kenneth W. , Roy Kenneth P.
Published: October 2015

The design of privacy areas is very similar in offices, healthcare, and other building segments, but the focus is squarely on healthcare due to the HIPAA regulations involving personal medical information. Given the degree of enclosure provided by the walls, ceiling, doors, etc., common expectations by occupants of those closed spaces is for confidential speech privacy. So, how do we design and evaluate the speech privacy provided by medical offices, treatment rooms, conference rooms, etc. ASTM laboratory testing of components and systems including STC, CAC, and NRC are part of the answer. But the bottom line is in the field with actual performance testing of the systems as they are built and operated. Two questions to be answered are how do we make informed decisions about product and system choices, and how do we maximize speech privacy using those architectural choices.
Studying dolphin whistles in Mexico
Authors: Bazúa-Durán Carmen , Sarmiento-Ponce Julieta E. , González-Leal Brenda P. , Montejano-Zea Elena
Published: October 2015

Dolphin whistles are emitted especially during social interactions and feeding activities involving group cohesion, individual recognition, and recruitment. Here, at the Faculty of Sciences of UNAM we are studying dolphin whistles, mainly those of wild and captive bottlenose dolphins, Tursiops truncatus, to learn about their social structure and how whistles may be used to study dolphin ecology. We have developed a new methodology to describe and compare the whistle repertoire, which consists of whistle contour extraction to classify whistles into whistle types (using Matlab BELUGA and ArtWARP), then classifying whistle types into four general categories (high complexity, low complexity, linear long, and linear short), and finally computing a complexity index and a proportional variability of the whistle repertoire. Results obtained showed that this very simple method is useful to describe the whistle repertoire and to compare it according to the general behavioral state of dolphins, and between species. It is necessary to implement new methodologies like this one to better understand how dolphins are using whistles, since acoustic communication is the most important sense in dolphin species. [Work supported by PAPIIT-UNAM.]
Geographic variation assessment of Bryde's whale (Balaenoptera edeni) Be4 call in the Gulf of California
Authors: Vivas Eduardo , Vera Cuevas Violeta C. , Urbán Ramírez Jorge , Viloria Gómora Lorena , Cortés Calva Patricia
Published: October 2015

Mysticeti whales modify their calls in response to an increase in noise level within their environment. This is particularly important since environmental noise has been increasing continuously in the last decades. In the case of Bryde's whale (Balaenoptera edeni), previous studies of its predominant call, Be4, have exposed differences in the duration of its main component (f0) for northern and southern areas of the Gulf of California (GC). The objective of this research is to determine if the differences found among Be4 calls (f0, duration, and energy distribution) are influenced by the noise levels in those areas. Results based on the characterization of Be4 Call and noise show that northern noise level is intense in the octave frequency band centered around 30 Hz, and could mask the 30 Hz component. This kind of noise is rare in the south (5%) and when it was present, the 30 Hz component was not registered, which might be an adaptation to noise. Predominant moderate noise in the south within the band 20 to 70 Hz overlaps the signals and higher components are present, especially the 165 Hz component. Results suggest that the difference between call from north and south areas might also be related to the noise present.
An underwater acoustic camera for marine mammal vocalization interaction studies
Authors: Vivas Eduardo , Bustamante Omar , Beristain Sergio
Published: October 2015

Acoustic Cams, promoted as “a way to listening with your eyes,” are widely used in the industry to visually pinpoint particular sound sources in a clouded sound environment. A video camera and complex multiple microphone array configurations are used to find the direction of arrival of sound, and the results are color coded and superimposed in the video image. This technique has a great potential to be used in marine mammal studies where underwater vocal interactions among a close group needs to be determined. This is particularly important for Otariids and Pinnipeds for which the function of in-water calls involving no bubble emission needs to be studied. A prototype of an underwater acoustic camera built around a low cost open source linear array of hydrophones and a fishing underwater camera is presented. Results of the prototype test, first under controlled conditions, and then recording vocal interactions during normal swimming behavior of a colony sea lions (Zalophus californianus) in the Gulf of California, are presented.
A two-criterion model for microvascular bioeffects induced in vivo by contrast microbubbles exposed to medical ultrasound
Authors: Church Charles C. , Miller Douglas L.
Published: October 2015

The mechanical index (MI) assumes that bubbles of all relevant sizes exist in tissue, yet that assumption is approximated only in studies that include use of a microbubble contrast agent. If the MI is taken to be the key dosimetric parameter, then it should allow science-based safety guidance for contrast-enhanced diagnostic ultrasound. However, theoretical predictions based on the MI typically do not concur with the frequency dependence of experimentally measured thresholds for bioeffects. For example, experimental measurements of thresholds for glomerular capillary hemorrhage in rats infused with contrast microbubbles (Miller et al. UMB 2008;34:1678) increase approximately linearly with frequency while the MI assumes a square-root dependence. Here, thresholds for inertial cavitation were computed for linear versions of the acoustic pulses used in that study assuming bubbles containing either air, C3F8, or a 1:1 mixture of the two and surrounded by either blood or kidney tissue. While no single threshold criterion was successful, combining results for one criterion that maximized circumferential stress in the capillary wall with another that ensured an inertial collapse, produced thresholds that were consistent with experimental data. This suggests that development of a contrast-specific safety metric may be achieved by further testing and confirmation in different tissues.
Acoustic scattering from rib-stiffened finite bilaminar composite cylindrical shells- 3-D solution
Authors: Hayek Sabih I. , Boisvert Jeffrey E.
Published: October 2015

The acoustic scattering from an insonified finite bilaminar cylindrical shell stiffened by a thin circular rib-stiffener is analyzed. The two cylindrical shell laminates are perfectly bonded having the same lateral dimension but have different radii and material properties. The bilaminar shell is analyzed using the exact theory of three-dimensional elasticity. The thin rib-stiffener has rectangular cross-section and is perfectly bonded to the inside of the inner shell. It is analyzed as a thin elastic ring. The finite shell has shear-diaphragm supports at ends z = 0 and L and is terminated by two semi-infinite rigid cylindrical baffles. The shell is insonified by an incident plane wave at an oblique incidence angle. The scattered acoustic farfield is evaluated for various incident wave frequencies and stiffener location and dimensions. A uniform steel stiffened shell in water was initially analyzed to study the influence of stiffened-shell geometries on the scattered acoustic farfield. A second shell made up of an outer elastomer shell bonded to an inner stiffened steel shell was also analyzed to study the influence of elastomeric properties on acoustic scattering. [Work supported by NAVSEA Division Newport under ONR Summer Faculty Program.]
The acoustic complexity of keyboard percussion instruments. Part II: What we know and what we wish we knew Leigh Howard Stevens
Authors: Stevens Leigh H.
Published: October 2015

Part II Resonating chamber shapes, their Q factor, their resultant musical character Resonating Chambers come in many shapes and sizes and largely determine the power, focus, and sustain of whatever the associated tone bar is coupled with it. The most basic box resonators are found on elementary education musical instruments such as Carl Orff tuned percussion instruments: demonstration of various tone bars resonating over box, rectangular, square and round tube resonators; demonstration of high and low Q systems responding to the same tone bar; demonstration of well-tuned, miss-tuned, and deliberately de-tuned partials on various tone bars; and questions from (and challenges to!) the audience.
Radial mode analysis of broadband noise in flow ducts using azimuthal sensor array
Authors: Xu Kunbo
Published: October 2015

For the evaluation and improvement of noise reduction notions and the verification of broadband sound power measurement in flow ducts, it is interesting to obtain the detailed information of the in-duct acoustic mode spectrum and subsequent broadband noise sources separation. A new broadband noise mode analysis method, which uses full wall-mounted sensor array, was experimentally applied on broadband sound fields at three operation conditions, which were generated by means of high loaded single-stage axial flow fan test rig. Two axial sensor arrays were mounted wall-flush upstream of the fan. Measurements were made at operating conditions from 60% to 100% rotor design speed. On the whole, the new method behaves robustly. It delivers physically meaningful broadband mode amplitudes. Mode coherence functions are calculated between all pairs of propagating modes. This feature enables the detailed comparison of different sound fields with characteristically coupled mode pairs. For tonal noise, mode coherence results show that modes are correlated with the source and with each other, especially at blade passing frequencies. The experimental outcome proves the usefulness of the analysis technique for interpreting andunderstanding broadband sound propagation in turbomachinery flow ducts.
Acoustic field of a shielded rectangular supersonic jet
Authors: Gutmark Ephraim , Mora Pablo , Baier Florian
Published: October 2015

The impact of a flat surface installed parallel to a supersonic rectangular jet of AR = 2 on the far field noise is studied. Far-field cold jet results at design, over-expanded and under-expanded conditions are compared between the free-field jet, the nozzle with the surface matching with the exit lip (h = 0De), and the surface at different stand-off positions away from the jet axis, h = 1, 2, 3 De. Results are shown for all jet azimuthal angles. When the surface is installed at h = 0De, broadband shock-associated noise intensity was decreased and its peak frequency shifted. At NPR = 2.5, shock noise appears to be entirely mitigated. Also, a low frequency noise component is observe below St = 0.15, and assumed to be related to the trailing edge/jet plume interaction. At NPR = 3.0, strong screech tones are mitigated with the surface installed at h = 0De. In the shielded region, noise levels are significantly lower for all plate positions. Mixing noise and Mach wave radiation are affected by the plat stand-off location at the ϕ = 90o. Heated jet measurements up TR = 3.0, near-field and high-speed shadowgraph visualization are performed and reported.
Analytical intensity calculated from a wavepacket model and comparison to intensity measurements near a high-performance military aircraft
Authors: Whiting Eric B. , Stout Trevor A. , Gee Kent L. , Neilsen Tracianne B. , Wall Alan T. , James Michael M.
Published: October 2015

To create an equivalent source description of jet noise, a wavepacket model is used to determine the acoustic vector intensity away from the source. This paper represents an initial investigation into using the measured vector acoustic intensity to define wavepacket parameters. The complex pressure of a line source is defined according to an analytical hyperbolic tangent wavepacket model and Rayleigh integration is used to find the pressure, particle velocity, and time-averaged intensity at observer locations. The parameters that define the shape of the wavepacket are initially based on prior pressure level-based optimization carried out for ground-based microphones. The resulting calculated acoustic intensity vectors are compared to vector intensity measurements previously taken near a tethered high-performance military aircraft at military and afterburner engine conditions. The wavepacket parameters are then varied to provide an optimal fit using the intensity, rather than pressure level, as the cost function, and the differences between the two models are described. [Work supported by the Office of Naval Research.]
Loudness effect on pairwise comparisons and sorting
Authors: Susini Patrick , Houix Olivier , Saint Pierre Guillaume
Published: October 2015

Effect of loudness on the perceptual structure underlying a corpus of sounds is investigated by two experimental methods: pairwise comparisons and sorting. Both methods are applied to a corpus of recordings sounds presented with their ecological, non-normalized loudness, and to the same corpus equalized in loudness. Two types of perceptual structures (multidimensional scaling and hierarchical cluster analysis) are derived. Domination of one auditory attribute—loudness—on less salient ones is discussed according to the two types of perceptual structures. In the non-loudness-normalized corpus, loudness was the main factor explaining participant’s judgments for both tasks. In particular, representations derived from sorting data almost solely reflected sound pressure level difference between sounds. On the opposite, loudness normalization allowed the emergence of several predicted auditory attributes that characterize the tested sounds. On that second corpus however, sorting data were found less appropriate than pairwise data to provide interpretable continuous dimensions.
The perception of vocal characteristics in normal-hearing and cochlear-implanted children
Authors: Baskent Deniz , Libert Jacqueline , Vickers Deborah , Gaudrain Etienne
Published: October 2015

Voice characteristics provide important cues for many speech-related tasks, such as gender categorization, vocal emotion perception, and understanding speech in the presence of competing voices; tasks known to be difficult for cochlear implant (CI) users. While most related research has focused on voice fundamental frequency (F0), the work from Smith et al. [J. Acoust. Soc. Am., vol. 117, pp. 305–318, 2005] has shown the importance of another voice characteristic: the vocal tract length (VTL; related to speaker size). Recent work has indicated that while CI users have difficulty in utilizing F0, they are even more limited at VTL perception. This study aimed to further understand factors potentially contributing to this limitation, by exploring F0 and VTL perception in NH children and children with CIs. We hypothesized that children may learn to utilize F0 before VTL cues because of exposure to exaggerated F0 cues in infant-directed-speech, and acquisition of VTL cues may be later, due to the necessity for exposure to multiple talkers; implying a hierarchy in processing the two vocal cues. We further hypothesized that children with CIs may be better at processing voice cues than adult-implanted CI users, suggesting that these perceptual cues could be learned.
Verification of an automated headphone-based test of spatial release from masking
Authors: Gallun Frederick J. , Kampel Sean D. , Jakien Kasey M. , Srinivasan Nirmal K. , Stansell Meghan M. , Gordon Samuel Y.
Published: October 2015

Currently, there are many different laboratory-based tests of spatial release from masking (SRM) that use speech materials; however, there is still disagreement as to the impact of age and hearing loss on SRM. The time is ripe, then, for taking these tests out of the laboratory and testing larger numbers of listeners varying in age and hearing ability in order to provide the statistical power needed to answer the questions currently being asked. Unfortunately, most of the tests that have been developed are either open set, and thus require a tester to administer them, or require complex soundfield speaker arrays. Our laboratory has recently developed and verified an automated headphone-based test that can be presented in only five to ten minutes and that provides results that are predictive of results obtained in an anechoic chamber. The data associated with the verification of this test procedure will be presented.
Periodically distributed piezoelectric patches optimization for waves attenuation and vibrations damping
Authors: Collet Manuel , Fan Yu , Ichchou Mohamed
Published: October 2015

The deformation of a structure can be understood as a superposition of waves which are induced by the excitation and reflected by the boundaries. According to this regard, attenuations of waves can lead to a strong reduction of the structural response and prevent energy to be propagated. In this work we consider periodically distributed piezoelectric patches onto the host structure so that by designing shunted electric circuits the properties of the waves can be modified. The success of the idea is also directly related to the extent of electromechanical coupling. In terms of structural modes, the coupling factor can be estimated by the open-circuit (OC) and short-circuit (SC) natural frequencies. However, in terms of waves, few criteria are available. In this work, a wave-based criterion is proposed to evaluate the coupling factor of the piezoelectric composite. To do this, enhanced Wave and Finite Element Method (WFEM) is employed to obtain the dispersion relations and the shapes of the waves. Then, the factor can be calculated in three different but equivalent formulas. An example is given thereafter, where a piezoelectric waveguide with semi-active circuits is used to control the energy flow from a source to the far-field. We show that the coupling factor is frequency dependent and it is strongly related to the geometric parameters; therefore, it significantly changes the optimal performance of the piezoelectric waveguide and it capacity to dampen vibrations.
Eliciting comparable, natural speech from children and adults
Authors: McCullough Elizabeth A. , Clopper Cynthia G. , Wagner Laura
Published: October 2015

In sociophonetic studies, the goal of eliciting natural speech is often at odds with the goal of eliciting speech that is easily comparable across participants. In this examination of regional pronunciation variation among English-speaking children and adults in the United States, these goals were balanced using two speech elicitation methods: color naming and picture-prompted storytelling. In the color naming task, participants saw solid blocks of color on a computer screen and were recorded saying the name of each color. In the storytelling task, participants were recorded narrating the familiar stories of Little Red Riding Hood and Goldilocks and the Three Bears using self-paced picture prompts. These methods were successfully used with participants of a wide range of ages, from pre-literate children (4 years old) to older adults (75 + years old). The color naming task yielded largely identical target words across participants because only common colors were presented. While the storytelling task allowed participants to be more creative, targets such as character names, words for important objects in the stories, and canonical lines of dialog were repeated frequently across participants. Thus, these elicitation methods avoided naturalness concerns associated with read speech while providing identical word-length and similar sentence-length examples for comparison.