bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental changes in perceptual weighting and organization of speech.
Authors: Nittrouer Susan
Published: July 2011

Speech perception research and theory historically have focused on the role of discrete spectro-temporal bits of the signal, known as acoustic cues, in phonetic labeling. Following suit, work in development and/or disorders has asked if sensitivity to these cues is diminished in children or disordered populations relative to typical adults. Although outcomes with disordered populations provide a controversial account, clearer is the conclusion that typical children have sufficient sensitivity to these cues from infancy. Yet equally clear is the finding that abilities to recover phonetic structure in one’s first language emerge only gradually over the first decade or so of life, suggesting more may be involved in mature speech perception than has heretofore been considered. This presentation reviews what research has been done on developmental changes in three phenomena that might help explain that protracted period of development for speech perception: (1) weighting strategies for the numerous cues available for separate phonetic decisions, (2) signal structure that is temporally longer and spectrally broader than acoustic cues, termed “global” structure, and (3) perceptual organization of various kinds of signal structure. These findings should prompt innovation moving forward in how investigators examine developmental change in speech perception. [Work supported by NIDCD Grant DC-00633.]
Electrophysiology of infant speech feature detection and discrimination.
Authors: Cone Barbara , Baker Kristin , Liu Jessie
Published: July 2011

Cortical auditory evoked potentials (CAEPs) were obtained from awake, typically developing, normally-hearing infants, aged 4–10 months, in response to speech sound tokens. In experiment 1, 50-ms tokens of “Ling sounds” (/a/, /i/, /u/, /s/, /∫/, /m/) and 50-ms tone bursts at 500–4000 Hz were used as stimuli and presented at 10 dB level increments to develop CAEP latency and amplitude input-output functions. Observer-based psychophysical methods were used to determine detection thresholds for the tone bursts and speech tokens. Infant thresholds were elevated by more than 20 dB for tone bursts and by more than 30 dB for speech tokens with respect to adults. CAEP input-output functions in infants had significantly steeper slopes than those for adults. In experiment 2, 500-ms synthesized vowel tokens (/a/, /i/, /o/, /u/) were used to evoke CAEP components P1-N1-P2 and the acoustic change complex (ACC). Observer-based psychophysical methods were used to determine the infants’ ability to discriminate between these vowel sounds. Robust ACCs were obtained for all vowel contrasts even when behavioral tests of discrimination were not successful. The results of these experiments will be discussed with respect to the development of the neural generators responsible for CAEP and perceptual abilities.
Effect of reward in a new localization test method for children under 5.
Authors: McCartney D. A. , Church C. J. , Seeber B. U.
Published: July 2011

Absolute localization ability in children under 5 has rarely been measured. One of the reasons for this is the difficulty of keeping the child engaged long enough in the task to obtain sufficient data. This was addressed by developing an uninstructed game-like localization task in which children must find the location of sounds. Correct localization responses, defined as a head or eye movement toward the sound’s location, are reinforced with visual rewards. These are presented on video walls surrounding the child. This study investigated how varying the location of the visual reward affected the number of correct responses obtained. The study used three visual reward strategies: (I) the reward always presented at 0 deg (front), (II) the reward presented at the sound’s location, and (III) the reward varied randomly ± 20 deg about the sound’s location. Preliminary analysis of data from 24 children (15–56 months) shows a significant effect of reward strategy and age. More correct responses were generally obtained using reward strategies (II) and (III). Reward strategy (III) is preferred for use in a refined localization test because the reward is not presented at a fixed set of locations, helping to avoid visual learning of the test directions.
Panel contribution analysis for the interior region of a complex structure using the Helmholtz equation least squares method.
Authors: Natarajan Logesh Kumar , Mylavarapu Sandeep , Wu Sean
Published: July 2011

The paper presents an experimental study on using Helmholtz equation least squares based nearfield acoustic holography to perform panel contribution analysis inside a complex structure with overall dimensions of 21 × 14 × 14 in.3 in the shape of an automobile passenger compartment. A point random force was used to excite this structure. The radiated acoustic pressures were measured by a linear array of 13 microphones scanning over the interior surface at close distances, resulting in 520 measurement points. These measured acoustic pressures were used to reconstruct the vibro-acoustic responses, including the normal surface velocity (NSV) and surface acoustic pressures (SAPs) of the cabin. Next, the reconstructed NSV and SAP are used to determine the normal-component of the time-averaged acoustic intensity on the surface, which was then correlated to the sound pressure level at any field point, say, at the driver ear position inside the cavity. The relative contributions from individual panels toward a specific field point are calculated by summing the acoustic power flow from individual panels, and their ranking is determined. The major advantage of this approach is that panel contributions toward any number of field points can be determined based on a single set of measurements.
Designs for construction of quiet composite sandwich structures.
Authors: Nutt Steven , Naify Christina J.
Published: July 2011

Sandwich structures are comprised of a low-density core sandwiched between two thin, stiff facesheets, often composite laminates. The construction of the sandwich structure is designed to optimize the high-bending stiffness-to-weight ratio necessary for aerospace applications. Although the high stiffness-to-weight ratio of sandwich structures is ideal for bearing mechanical loads, a trade-off exists between mechanical and acoustic performance, in that increases in one generally come at the expense of the other. Improvement of TL of sandwich panels can be divided into three general categories: altering the panel construction by changing the core/facesheet materials, use of active or semi-active vibration suppression, and finally, added treatments such as foams, fibers, or other structures to either the exterior of the panel, or inside the core. TL of sandwich structures using these strategies is presented, in addition to explanation of the physical principals responsible for the decrease in transmitted sound. Featured approaches include design of core and facesheet materials, attachment of layered gasses to the panel facesheet, and insertion of midplane membrane-type metamaterial to the core. Advantages and disadvantages of each strategy are also considered and discussed.
Novel sandwich composite aircraft sidewall architectures.
Authors: Palumbo Dan
Published: July 2011

An aircraft sidewall constructed of honeycomb sandwich composite materials could have a mass per unit area, which is 60% less than a comparable stiffened aluminum structure. With reduced weight, the sandwich composites have a high stiffness to mass ratio which yields high radiation efficiency with the result that the sandwich composite can have a transmission loss up to 10 dB less than its aluminum counterpart. A lightweight sandwich composite fuselage will then produce higher cabin noise levels and require additional treatment. The initial weight savings gained through the use of the composite material would be compromised by the need for the additional treatment. It may be possible to the reduce radiation efficiency of sandwich composites through novel features machined into the material’s core. To explore this possibility, several Nomex honeycomb, sandwich composite panels were designed constructed and tested. The performance of the composite panels in terms of both transmission loss and vibration response will be compared to that of a stiffened aluminum panel. It will be shown that it is possible to recover a good portion of the transmission loss reduction incurred with respect to the aluminum structure without sacrificing panel strength.
Effect of surface treatment of graphite nanoplatelet on damping properties of polyetherimide nanocomposites.
Authors: Li Bin , Olson Erik , Zhong Weihong
Published: July 2011

Polyetherimide (PEI) with excellent mechanical properties and thermal stability is gaining popularity as infrastructure materials in aircraft and ground transportation. Exfoliated graphite nanoplatelet (GNPs) composed of stacked 2-D graphene layer, have shown great potential as a damping property modifier, owing to their high mechanical performances and strong interlayer frictional motion. Interface bonding between the nanofiller and the polymer matrix is critical to the properties of polymer nanocomposites. This paper reports the investigation on PEI/GNP nanocomposites for their dynamic mechanical properties, specifically to fabricate polymer composites with superior damping properties. In order to determine the effects of interfacial bonding between PEI and GNPs, the GNPs were surface treated by different amounts of silane ([3-(2-aminoethylamino) propyl] triethoxysilane. Preliminary results indicated that adding both types of GNP with and without the silanization treatment does increase the storage modulus of PEI, but surface treated GNP shows much better efficiency in improving the damping capability, compared with pristine GNP, especially at high dosage of silane surfactant.
Analysis of sound transmission through sandwich panels.
Authors: Li Zhuang
Published: July 2011

Due to their advantages over the conventional metal structure, sandwich structures have become used increasingly in transportation vehicles in recent years. However, they have some less favorable properties. In this paper, sound transmission through foam-filled honeycomb sandwich panels was studied using the statistical energy analysis (SEA). Modal density, critical frequency, and the radiation efficiency of sandwich panels were analyzed. The sound transmission loss and radiation efficiency of sandwich panels were predicted theoretically and measured experimentally. The measured results agree with the theoretical predictions quite well. An important observation is that, for foam-filled honeycomb sandwich panels, the radiation efficiency does not decrease to a plateau value at frequencies beyond the critical frequency. Although the high damping helps to improve the sound transmission loss in the critical frequency range, the overall transmission loss of sandwich panels is lower than their heavy metal counterparts. Therefore, the foam-filled honeycomb design must be modified to obtain good noise isolation capability, and a trade-off between the overall stiffness and the sound transmission properties should be considered in the design stage.
The productivity of structure-dependent tone sandhi in Shanghai Chinese.
Authors: Zhang Jie , Meng Yuanliang
Published: July 2011

Shanghai Chinese is noted for its structure-dependent tone sandhi patterns: its five lexical tones undergo two types of tone sandhi: a word with a modifier-noun structure undergoes a left-dominant sandhi, whereby the initial tone is spread across the entire word; a word with a verb-noun structure, however, may undergo a right-dominant sandhi that reduces the tonal contours on nonfinal syllables, but preserves the tone on the final syllable, especially if the word is of low frequency. A wug test was conducted to investigate the productivity of the two types of sandhis. Four types of disyllabic words were tested for each underlying tonal combination: real words, novel words composed of two legal syllables, and novel words in which either the first or the second syllable was a non-existing syllable in Shanghai. The syntactic structures of the words were cued by carrier sentences. 48 speakers of Shanghai (20 M, 28 F) participated in the experiment. The f0 results for the experimental stimuli will be reported and discussed in the context of the effect of structure dependency on tone sandhi productivity and how this effect interacts with those of lexical frequency and the phonetic properties of the sandhis.
The interlanguage speech intelligibility benefit-listeners for Chinese accented English liquids.
Authors: Lee Joo-Kyeong , Xue Xiaojiao
Published: July 2011

This study investigated the intelligibility of Chinese-accented English liquids for native English, Chinese, and Korean listeners. The lateral /l/ and the retroflex /r/ in syllable initial and final positions were examined in three different contexts: segment, word, and sentence. Three groups of listeners with different language backgrounds accomplished a forced-choice identification task. For Chinese talkers’ production of the English liquids, both matched and mismatched interlanguage speech intelligibility benefits for listeners (ISIB-L) occurred in all the four positions except for the initial /l/ produced by low proficiency Chinese talkers. The ISIB-L, however, held only for high proficiency non-native listeners. The only exception was the syllable initial /l/ stimuli produced by low proficiency Chinese talkers in such a way that native English listeners were more accurate than Chinese and Korean listeners at identifying the strong Chinese accented syllable initial /l/ sound. Considering the contextual effects on ISIB-L, matched ISIB-L only occurred for high proficiency listeners in the segment context. There was evidence of both matched and mismatched ISIB-L effects only for high proficiency listeners in word context. In the sentence context, English listeners performed better than all non-native listeners; therefore, there was no evidence for ISIB-L.
The discrimination and categorization of German /r/ allophones by American English speakers.
Authors: Tepeli Dilara
Published: July 2011

This study investigates the discrimination and categorization of two German /r/ allophones—the uvular fricative [R’] and the uvular trill [R]—by experienced and naive American English (AE) speakers. Two groups of AE speakers participated in a categorization experiment followed by a discrimination experiment. Preliminary results suggest that experienced AE speakers perceive both variants predominantly as a German /r/ sound, followed by an English /r/ sound. Inexperienced AE speakers also predominantly perceive both variants as a foreign /r/; however, their second most frequent selection during the experiment was “no category,” reflecting their inability to categorize the two variants. These results suggest a qualitative perception difference between the two groups. The experiment also revealed no significant categorization difference between the two types of /r/ allophones. The results of the discrimination experiment revealed that both groups of AE speakers performed equally well on average; however, the standard deviation of percent correct scores is greater for inexperienced AE participants than experienced AE participants. The obtained results will be discussed in relation to existing second language acquisition models.
Perceived similarity of English, Korean, and Japanese consonants for the native speakers of these languages.
Authors: Nozawa Takeshi , Cheon Sang Yee
Published: July 2011

The present study investigated how linguistic experience would influence the perceived similarity between native and non-native and between two non-native consonants. Three native speakers of English, Korean, and Japanese produced consonants of their respective L1 in /Ca/ context. Native speakers of these three languages served as listeners. They heard two stimuli per trial and rated how close the initial consonants of the stimuli are in seven-point scale. A two-way ANOVA yielded a significant main effect of consonant pairs and an interaction effect of consonant pairs and listener groups. The results generally show that the phonology of listeners’ L1 affects the perceived similarity. Japanese listeners rated English and Japanese voiceless stops, which are rather distant in VOTs, more similar than English and Korean listeners did. Korean listeners rated English voiced stops and Korean lax stops more similar than did the other two listener groups. English listeners rated Japanese liquid and English /r/ or /l/ more different than did Japanese and Korean listeners. All the listener groups rated English /s/ and Korean /*s/ as very similar. However, only Korean listeners rated English /s/ and Korean /s/ as rather distant while English and Japanese listeners rated them as similar.
Hemispheric processing of tones by listeners with or without tone experience.
Authors: Wu Xianghua , Munro Murray , Wang Yue
Published: July 2011

Tones are used phonemically in many languages such as Mandarin, Thai, and Norwegian. Previous research [Wang et al. (2004)] revealed left hemispheric preference for Mandarin listeners in the processing of native tones, but no preference for either Norwegian or English listeners, even though the latter two differed in familiarity with tones. The current study examined hemispheric processing of Mandarin tones by 20 native listeners each of Mandarin, Thai, and English. The Thai listeners had experience only with Thai tones, while the English listeners had no tone experience. In a two-response dichotic listening paradigm, listeners reported the tone they heard in each ear. The pooled results across tones indicated left hemispheric preference for the Mandarin listeners, no hemispheric preference for the Thai listeners, and right hemispheric preference for the English listeners. The findings suggest that native tone experience may increase left hemisphere involvement in the processing of tones in another tone language, whereas lack of tone experience in the native language tends to be linked to non-linguistic hemispheric lateralization of tone processing. [Work supported by SSHRC.]
On the intelligibility of fast synthesized speech for people who are blind: A cross-system comparison.
Authors: Syrdal Ann , Mishra Taniya , Stent Amanda
Published: July 2011

People who are blind increasingly use synthesized speech as a primary output modality when interacting with computers, mobile devices, and web-based services. They typically prefer to listen to the synthesized speech at speeds multiple times real time, and consequently develop strong preferences for particular text-to-speech (TTS) engines and voices. These usage-based preferences lead to potentially incorrect assumptions about which TTS approaches are “best” for fast speech. We report on a cross-system comparison of the intelligibility of fast synthesized speech for users who are blind from birth. We used male and female voices from multiple TTS engines representing the main approaches to TTS: diphone synthesis, unit selection synthesis, HMM-based synthesis, and formant synthesis. We recruited participants from organizations that work with the blind. Each participant listened to and transcribed semantically underspecified sentences from a single TTS engine and voice, spoken at speeds ranging from 300 to 550 words/min. We used TTS engine, algorithm for speeding up synthesized speech, and speaker sex as independent variables, and transcription accuracy as the primary dependent variable. We report differences by TTS approach, speed up method, TTS engine type, and speaker sex.
The waveform model of vowel perception and production.
Authors: Stokes Michael A.
Published: July 2011

The waveform model of vowel perception and production was published in late 2009, but it has not been publicized or exposed to a wide audience before now. In this presentation, the framework of the waveform model will be explained beginning with the categorization of the vowel space, and the distinguishing features for each categorical vowel pair. From the well defined categories, the position of the lips and tongue and their association with specific formant frequencies becomes apparent, as well as an explanation of perceptual errors. With this foundation, the experimental evidence that led to 99.2% accuracy across the 50 male talkers in the Hillenbrand et al. dataset (1995) will be presented. The 99.2% performance was achieved with 64 lines of computer code processing the data points of the 396 vowels stored in a database. The waveform model provides a unique categorization of the vowel space, which has led to a working explanation of vowel perception, vowel production, and perceptual errors. By explaining each of these aspects of vowel communication and achieving 99.2% accuracy with a computer algorithm, the waveform model will have an impact in more than one field of research.
Categorical processing of German vowel quantity.
Authors: Tomaschek Fabian , Truckenbrodt Hubert , Hertrich Ingo
Published: July 2011

The present study investigates the behavioral and neural processing of duration in the German vowel /a/ using synthesized disyllabic nonsense words. The vowel /a/ was chosen since its long and short cognates are differentiated merely on the basis of vowel duration, unlike high and mid vowels which have additional differences in formant structure. By means of an identification test a sharp category border was found at 105.9 ms in theduration continuum from short to long category associated with a local peak in reaction time. Furthermore, an adaptive discrimination test applied to the entire continuum showed a minimum of the just-noticeable-difference for vowel duration at the category border. In an MEG study, the continuumof the disyllabic words was presented in randomized order. Besides two P50-M100 complexes in response to the first and the second syllable, the ERP data showed a secondary M100-like peak in case vowel duration exceeded the duration of the short category, which was not observed in a duration-matched nonspeech control condition. This secondary M100 might be interpreted as an additional phonological “event” or “slot”, indicating a nonlinear categorical difference in the processing across short and long vowels.
Brief accent exposure promotes early word learning in accented speech.
Authors: Schmale Rachel , Cristià Alejandrina , Seidl Amanda
Published: July 2011

Foreign accents incur processing costs for monolingual listeners, compromising speech perception for both adults [Munro and Derwing (1995)] and infants [Schmale and Seidl (2009)]. However, some adult work suggests that this disadvantage is modulated by accent experience [Bradlow and Bent (2008)]. It remains unknown whether exposure to foreign-accented speech would reveal similar benefits for toddlers, who cannot exploit lexical, top-down information. Previous work demonstrates that English-learning 24-month-olds cannot learn words when trained by a native-English talker and tested by a Spanish-accented talker [Schmale, et al. (in press)]. Findings are presented from four experiments with 24-month-olds (n = 88) using this word-learning task preceded by a 2-min exposure phase. In experiments 1 and 2, toddlers heard speech from Spanish-accented speakers in exposure (single speaker in 1; multiple speakers in 2). Looking times revealed that exposure supported word learning (p = 0.002 and p = 0.003, respectively). To tease apart the role of accent and talker variation in bolstering learning, in experiments 3 and 4 toddlers heard speech from native-English speakers in exposure (single speaker in 3; multiple speakers in 4). Looking times revealed that they failed to learn words in both experiments (p = 0.07 and p = 0.5, respectively). These results demonstrate that accent exposure bolsters early cross-accent word learning.
Propagation in a waveguide with range-dependent seabed properties. I. Theory and implications.
Authors: Holland Charles W.
Published: July 2011

The ocean environment contains features affecting acoustic propagation that vary on a wide range of time and space scales. A significant body of work over recent decades has aimed at understanding the effects of water column spatial and temporal variabilities on acoustic propagation. Much less is understood about the impact of spatial variability of seabed properties on propagation, which is the focus of this study. Here, a simple, intuitive expression is derived for propagation with range-dependent boundary properties and uniform water depth. It is shown that incoherent range-dependent propagation depends on the geometric mean of the seabed plane-wave reflection coefficient and the arithmetic mean of the cycle distance. Thus, only the spatial probability distributions (pdfs) of the sediment properties are required. Also, it is shown that the propagation over a range-dependent seabed tends to be controlled by the lossiest, not the hardest, sediments. Thus, range-dependence generally leads to higher propagation loss than would be expected, due, for example, to lossy sediment patches and/or nulls in the reflection coefficient. The theory may be useful for other (nonoceanic) waveguides. [Research sponsored by the Office of Naval Research Ocean Acoustics Program.]
Effects of coupling of forward-backward modal components on continental slope ocean environment.
Authors: Knobles David P.
Published: July 2011

An exact solution to the two-dimensional (2-D) Helmholtz equation in an inhomogeneous environment may be expressed as a superposition of forward and backward traveling modes. The modal amplitudes of both components are generally coupled in the same manner that positron and electron amplitudes are coupled in the presence of an electric field, resulting in Zitterbewegung for the electron. In ocean acoustics, an accurate treatment of such coupling can become important over long propagation distances across continental slope environments with inhomogenities in either the surface or bottom boundary conditions, the volume of the water column, or both. The coupled integral equation for the range-dependent modal amplitudes is decomposed into the forward and backward modal components using the asymptotic boundary conditions of Green’s function operator. In addition to an exact treatment to the coupling, a perturbation approach is introduced to include the forward-backward coupling effects within a one-way integral equation. The perturbations are introduced via a channel elimination approach that results in a nonlocal optical potential or effective interaction. The nature of this potential and the perturbation convergence criteria are examined for the case of bottom sand dunes and internal waves. [Work supported by the ONR.]
Bottom parameter behavior in slightly range-dependent shallow water.
Authors: Tolstoy A.
Published: July 2011

An examination of the matched field processing behavior of key geoacoustic parameters as a function of frequency (25–100 Hz), range (250 m–2 km), and sediment layer thickness (12, 22, and 40 m) in a systematic manner can be very helpful in the design of inversion methods. Even in the presence of small expected geometric errors (in source depth, phone depths, and source range) plus small errors in ocean sound-speed and bottom depths (with a slight range dependence), some low frequencies and close ranges can be surprisingly sensitive to bottom properties while still very effectively and efficiently indicating correct bottom values. Simple averaging over all such frequencies and ranges may not be optimal for maximizing sensitivity and, thus, for finding geoacoustic parameters.
Modeling backscatter from a series of sediment rough interfaces by a normal incident chirp sonar.
Authors: Tang Dajun
Published: July 2011

Chirp sonar is widely used as a survey tool in shallow water. A chirp sonar measures reflection and backscatter of normal incident sound from sediment interfaces and volume heterogeneity. Motivated by using such chirp sonar data to invert for goeacoustic parameters, a forward model is developed that uses an exact method on which practical models can be based. Here volume heterogeneity is ignored and only scattering by a set of rough interface is modeled. If these interfaces are flat, the received data will be a series of reflections from the interfaces. However, these interfaces are in general rough and a forward model should be able to quantitatively handle scattering from these rough interfaces, including full scattering from each interface and multiple scattering among the set of interfaces. A set of integral equations is derived, which provides the numerical mechanism to calculate the scattered field from the rough interfaces, and numerical examples are presented.
Transducer research at Bell Laboratories under Manfred Schroeder.
Authors: Sessler Gerhard M.
Published: July 2011

Electro-acoustic transducers were one of the research topics in Manfred Schroeders Laboratory at Bell Labs. One of the early highlights was the invention of the polymer-film electret microphone in 1962. Over the years, the activities were extended to the investigation of appropriate electret materials, to directional microphones, and to microphone signal processing. Manfred himself always had a keen interest in this field and made some notable contributions such as the design of directional microphones based on gradients of various orders with toroidal and unidirectional directivity characteristics. The search for electret materials suitable for electro-acoustic transducers led to the discovery of the superior charge retention properties of the fluoropolymers. Apart from microphones, other types of transducers such as touch actuators, transducer arrays for acoustic holography, and sensors for the detection of acoustic ion waves were investigated. Much of the later work of the author, performed at the TU Darmstadt, was based on the results of the early studies at Bell Labs. Examples are the introduction of silicon-based condenser microphones made with the methods of micromachining, using electret or external biasing, and new types of piezoelectric transducers consisting of charged cellular polymers, so-called ferroelectrets.
Acoustic work with Ron Schusterman and Dave Kastak.
Authors: Gentry Roger L.
Published: July 2011

This paper describes auditory-related work done with Ron Schusterman from 1964 through 2002, and with Dave Kastak from 1999 to 2007. Some of Schusterman’s early experiments failed to demonstrate echolocation in pinnipeds, resulting in a conflict with Poulter in 1965 that Ron did not resolve until 2000. He conducted several experiments to investigate what functions other than echolocation sea lion click vocalizations might serve. In 1965 he advised on measuring underwater auditory localization in sea lions, and between 1970 and 1976 he and his colleagues produced aerial and underwater audiograms for two seal species. His many other projects on hearing and vocalization, conducted with his colleagues, may be reviewed by other speakers in this symposium. Schusterman joined the NOAA panel writing noise exposure criteria for marine mammals from 1998 to 2002. In 2002 he asked Dave Kastak to replace him. Kastak then made significant contributions to the criteria from 2002 until his untimely death in 2007, just before the criteria were published. Auditory research lost two giants with their passing.
Hearing pathways in the finless porpoise, Neophocaena phocaenoides, and implications for noise impacts.
Authors: Mooney T. Aran , Li Songhai , Ketten Darlene R. , Wang Kexiong , Wang Ding
Published: July 2011

How an animal receives sound will influence how it uses or is impacted by sound. While the “jaw hearing” hypothesis is well supported, work has been limited to a few “representative” species. There are clear variations in the jaw and head morphologies of odontocete species suggesting subtle variation in sound reception. Here we address how a divergent cetacean species, the Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), receives sound. Noise impacts on this subspecies are a concern as they inhabit waters with many acoustic sources. Hearing was measured using auditory evoked potentials. Click and amplitude modulated tone stimuli were presented at nine locations on the head and body using a jawphone transducer. Thresholds were compared to anatomical dissections and CT scans of porpoise heads. Minimum thresholds and best hearing locations were at the cheek-fat-pad and distal to the porpoise bulla. However, thresholds were not substantially different at locations from the rostrum tip to the ear (11.6 dB). This minimal variation is quite different from the 30–40 dB differences found across the head of bottlenose dolphins and belugas suggesting differences in how divergent odontocetes receive sound. Porpoises may have relatively less “shading” of sounds and are potentially more susceptible to masking effects.
Noise-induced temporary threshold shift in marine mammals.
Authors: Finneran James J. , Schlundt Carolyn E.
Published: July 2011

In 1996, Dave Kastak and Ron Schusterman reported the first observations of noise-induced temporary threshold shift (TTS) in a marine mammal [D. Kastak and R. J. Schusterman, “Temporary threshold shift in a harbor seal (Phoca vitulina),” J. Acoust. Soc. Am. 100, 1905–1908 (1196)]. Since that time, a number of studies have been conducted to characterize the effects of noise on the hearing abilities of pinnipeds and odontocete cetaceans. These studies compare hearing thresholds before and after subjects are exposed to intense sounds and relate feature of the noise exposure to the observed threshold shift. The results are analogous to data from terrestrial mammals, where TTS depends on the frequency, amplitude, duration, and temporal pattern of the noise exposure, as well as the hearing test frequency and the recovery time. This talk reviews the major findings related to the growth and recovery of TTS in marine mammals, with an emphasis on recent data from high-frequency tonal exposures in bottlenose dolphins. The relationship between onset-TTS levels across a range of frequencies and proposed auditory weighting functions will also be discussed. [Work supported by the ONR.]
Developing auditory weighting functions in a bottlenose dolphin (Tursiops truncatus).
Authors: Schlundt Carolyn E. , Finneran James J.
Published: July 2011

The variation in susceptibility to noise as a function of frequency is handled by “weighting” sound exposures to emphasize frequencies where auditory sensitivity is highest. This technique allows the use of single, weighted numeric values for impact or damage-risk criteria, regardless of the sound frequency. Human weighting schemes were derived from measurements of equal loudness curves obtained from subjective experiments where listeners directly compare the loudness of sounds at different frequencies. Response times to acoustic detection tasks provide an indirect method to construct equal-latency contours in terrestrial mammals that are analogous to equal-loudness contours. The need for empirical measures of loudness contours or auditory weighting functions in marine mammals became especially apparent following experiments of temporary threshold shift (TTS) in dolphins that revealed frequency-dependent effects for onset-TTS levels. The objective of this effort was to develop auditory weighting functions for Tursiops truncatus by directly measuring subjective loudness as a function of the sound frequency. The resulting equal-loudness contours emphasize frequencies at which auditory sensitivity is highest and lessen the importance of other frequencies, similar to human A- and C-weighting networks. [Work supported by the ONR.]
Speciation and sounds of fishes: Dividing up the bandwidth.
Authors: Luczkovich Joseph J. , Sprague Mark W.
Published: July 2011

Fishes in the drum family (Sciaenidae) make sounds to communicate, but they do not make the same sounds. The species-specific calls have different dominant frequencies, are produced in spawning aggregations at different times of the day and season, and there is spatial segregation among the spawning fish populations. We predicted that the pattern of bandwidth use by these species would show low overlap in space, time, and sound frequency. We monitored the seasonal pattern of sound production of Sciaenidae in Pamlico Sound (NC) using autonomous sound recorders that recorded 10 s of sound every 15 min during May–Nov. The observed bandwidth ranges and spawning season for species are weakfish 300–400 Hz in May–Aug, silver perch 800–1500 Hz May–Aug, spotted seatrout 200–400 Hz June–Sep, red drum 100–200 Hz in Sep–Oct. Overlapping calls in these species were rare temporally and spatially, as evidenced by long-term passive acoustic monitoring. Two other species of fishes (oyster toadfish and striped cusk eels), in unrelated families, also compete for acoustic bandwidth in Pamlico Sound, but overlap temporally with the sciaenids. There is low probabilty of signaling confusion for these species but higher probability for Sciaenids. It appears that bandwidth partitioning has evolved in the Sciaenidae.
Seasonal chorusing in deep-water coastal habitats recorded off Oahu, HI.
Authors: Lammers Marc O. , Richlen Michael , Rosinski Anne E. , Au Whitlow W. L.
Published: July 2011

The acoustic behavior of animals living at the edge or below the photic zone is poorly documented. Limited opportunities to make recordings and/or behavioral observations in deep water environments have resulted in a paucity of information about sound production by animals living at depth. Here we report on an effort begun in 2006 to acoustically monitor deep reef environments off Oahu, HI. Ecological acoustic recorders (EARs) were deployed along the perimeter of the island and along the slope of a nearby bank at depths ranging between 115 and 575 m. At several locations, one of the predominant sounds recorded was a chorus of pulsed signals centered at approximately 4 kHz timed closely with the period following sunset. The duration of the chorus varies between 1 and 10 h in length and is tied to the lunar cycle. The chorus is seasonal, beginning in late December and ending in early June. This period corresponds closely with the seasonal presence of humpback whales (Megaptera novaeangliae) in Hawaii. The source of the chorus is presently still unknown, but being investigated using a combination of passive and active acoustic methods.
Responses of fish to underwater blasting signals: Application of the fish index trauma model.
Authors: Woodley Christa M. , Halvorsen Michlele B. , Carlson Thomas J.
Published: July 2011

The Columbia River Channel Improvement Project lead by the U.S. Army Corps of Engineers, Portland District included removal of a basalt rock ledge extending into the navigation channel, using confined underwater explosions. We performed compliance monitoring and conducted a study of the response of juvenile Chinook salmon (126.1 mm FL SD 24.8) and rainbow trout (68.3 mm FL SD 4.1) to blast signals. Cages designed for high velocity conditions contained depth-acclimated neutrally buoyant fry and juvenile salmonids and tourmaline blast sensors were placed 100–300 ft from the center of arrays of explosive charges. Blast durations ranged from 0.42 to 1.38 s, positive peak pressures ranging from 27.6 to 163.4 kPa, SELs ranging from 194 to 205 dB. Exposed fish were examined for physical damage at 0, 24, and 48 h postexposure. Injuries ranged from scale loss to lacerated organs. Some injuries lessened in severity over 48 h while others increased. Using an analysis model fish index of trauma (FIT), we described the exposure-response functions of the fish to the blast exposure. The FIT metric quantifies fish trauma and recovery potential for blast exposed fish and is sensitive to the onset of nonlethal injury at low severity exposure levels.
Role of environmental acoustic cues in the evolution of hearing specialization in cyprinidae.
Authors: Johnston Carol E. , Holt Daniel E.
Published: July 2011

Numerous studies have documented hearing specializations in fishes, but virtually no work has focused on the adaptive significance of sensitive hearing to fishes. An exception is the finding that marine clupeid fishes have an adaptation for hearing the ultrasonic acoustic signals of their mammalian predators, an obvious advantage. The idea that hearing specializations in most fishes evolved as a predator detection mechanism has not been tested in freshwater fishes, however, and due to ecosystem differences may not explain the evolution of such traits. Field observations suggested that cyprinids (Ostariophysi) congregate near areas of disturbed substrate to feed on dislodged aquatic insects and debris. This led to the exploration of whether the acoustic cues associated with substrate disturbance alone would attract cyprinds via a field playback experiment. These results may shed light on the detection of feeding cues as one of the potential selective pressures associated with the evolution of sensitive hearing in Ostariophysian fishes.
Real-time tumor ablation monitoring and mapping using harmonic motion imaging ex vivo and in vivo.
Authors: Konofagou Elisa , Hou Yi , Maleke Caroline , Marquet Fabrice , Vappou Jonathan
Published: July 2011

Harmonic motion imaging (HMI) uses a focused ultrasound (FUS) beam to generate an oscillatory acoustic radiation force for an internal, noncontact palpation to internally estimate relative tissue hardness. HMI estimates and maps the tissue dynamic motion in response to the oscillatory force at the same frequency, and has been shown feasible in simulations, phantoms, ex vivo human and bovine tissues, as well as animals in vivo. Using an FUS beam, HMI can also be used in an ideal integration setting with thermal ablation using high-intensity focused ultrasound (HIFU), which leads to an alteration in the tumor stiffness. In this paper, the capability of HMI to localize and target the tumor, as well as monitor its subsequent ablation, is assessed. The findings presented demonstrate that HMI is capable of both detecting and characterizing the tumor as well as efficiently detecting the onset of ablation. More importantly, HMI is shown capable of distinguishing the tumor margins from that of the thermal lesions in vivo in order to assess the treatment success. HMI may thus constitute an integrated, real-time method for efficient HIFU monitoring. [This work was supported by NIH Grant No. R21EB008521.]
Heat diffusion constrained inversion of backscattered ultrasound data to image temperature rise during high intensity focused ultrasound therapy.
Authors: Kaczkowski Peter J. , Speyer Gavriel , Brayman Andrew A. , Crum Lawrence A. , Anand Ajay
Published: July 2011

Noninvasive ablative high intensity focused ultrasound (HIFU) therapy must be guided with precision, and monitored in real-time. Magnetic resonance imaging (MRI) can provide both high resolution tissue-specific images and temperature maps, but even the most recently developed MRI methods cannot do so in less than a few seconds. Ultrasonic imaging techniques using a sequence of rf frames to measure heating-induced apparent strain have been developed to produce heating maps, but the approach is challenging due to lack of sensitivity and substantial variability in tissue properties. To improve estimates of temperature rise, constraints based on heat diffusion modeling are imposed, thus minimizing the effects of noise and nonmonotonicity of the speed of sound with respect to temperature throughout the therapeutic range. Furthermore, noninvasive protocols for measuring relevant HIFU field and tissue properties in the region of interest enable patient-calibrated mapping of temperature rise during HIFU, at ultrasonic imaging frame rates. Further analysis of the heat-induced apparent strain leads to a modal decomposition of the strain, greatly reducing the computational load for use in real-time feedback and therapy control. Finally, a Rytov approximation applied to the problem leads to further improvement in computational efficiency and physical understanding. [Work supported by NIH grant No. CA109557.]
Phase propagation in ultrasonic backscatter monitoring of high intensity focused ultrasound therapy.
Authors: Speyer Gavriel , Kaczkowski Peter , Brayman Andrew , Crum Lawrence
Published: July 2011

Phase propagation using the Rytov method has recently been proposed as a means for modeling the time-of-flight changes induced by thermal therapy [Speyer et al., J. Acoust. Am. 127]. These results are extended to measurements from a linear array, under which the general problem of imaging material changes is cast. The linear array offers several design components, which can be exploited for therapy monitoring, including the apodization and probing frequency. Phase propagation models are shown to be consistent with many aspects of conventional modeling, linearizing material changes around the same operating points as have been proposed by other researchers, and providing time-of-flight changes linearly related to the temperature distribution under these conditions. Beyond expanding on model properties, experimental evidence is presented, which indicates that phase propagation modeling is significantly more consistent with backscattered ultrasound data than conventional ray approaches. [Work supported by NIH Grant No. 5R01CA109557.]
How to improve the value of noise and performance data of fly-over measurements with high performance jets.
Authors: van Veen Theo , Lammen Wim , Dijkhuizen Johan
Published: July 2011

The quality and value of noise measurements of high-performance jets depend on a complex set of factors. A thorough preparation and analysis phase is not always standard practice. Critical factors during preparation are, for example, the selection of the location, the aircraft, the communication with the pilot, the design of the flight profiles during the runs, the method and instrumentation for recording of the aircraft performance, and noise and meteorological conditions during the test. After the test, a thorough analysis of the data has to be performed to select the data with the required quality. Further processing of this raw recorded data will lead to noise levels in corrected LAmax, SEL, or other metrics. In this paper attention is paid to the critical factors that can be influenced prior to the test and after the test to maximize the quality of the data used for noise calculations. A good preparation of the test and an analysis of the quality of the measured data set are essential to guarantee the acquisition of a high quality data set after fly-over noise measurements. The paper contains critical factors of a noise test with aircraft types like the F 16, F 18, and F 35.
Three-dimensional finite-difference time-domain/ray-tracing hybrid modeling of low-amplitude sonic boom diffraction around large buildings.
Authors: Cho Sang I. , Sparrow Victor W.
Published: July 2011

A hybrid method combining finite-difference time-domain (FDTD) and ray-tracing approaches is used for a 3-D numerical modeling of pressure loading on the exterior surface of large buildings due to an incoming low-amplitude sonic boom. The hybrid simulations model a field test conducted by NASA, where large building structures in Edwards Air Force Base were instrumented to measure their vibroacoustic responses to “low-booms” generated by F/A-18 fighter jets in a special dive maneuver. The low- and high-frequency contents of the low-booms are treated separately by the FDTD and ray-tracing parts of the hybrid model as the accuracy of each approach is restricted to its appropriate frequency limit. The simulation results agree well with the experiment for both single and multiple building cases. The building spiking effect, which describes the positive pressure spikes seen in the boom waveform recorded on the building side wall first impacted by the boom, is observed in each numerical simulation. [Work supported by NASA. The authors appreciate NASA making test data available for this work.]