bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges for the commercialization of acoustic sensors using microfabrication technologies
Authors: Pedersen Michael
Published: October 2013

In this paper a review is given of the methods used in the design and realization of acoustic sensors based on microfabrication technologies. It is shown that the most important issues relate to material properties, which must be tightly controlled to achieve acceptable consistency and stability of the devices. In addition, the requirements for successful commercialization of such devices are discussed and a number of critical parameters are identified which include environmental performance, reliability and cost. It is contended that microphones made with this new technology will not provide advances over existing technology in terms of sensitivity and noise performance, and hence the motivation for the use of the technology must be found in the added value of smaller size, increased bandwidth, and better flexibility in terms of device assembly and ruggedness. Based on these considerations a new capacitive microphone design is proposed, which simplifies the fabrication of the so-called free-plate or zero-stress microphone, referring to the lack of tension in the microphone diaphragm. It is further shown that the introduction of flip-chip assembly methods will enhance the repeatability and ruggedness of the microphone package, which so far has received little attention in the development micromachined acoustic sensors.
Violin normal mode radiative properties
Authors: Bissinger George , Keiffer John
Published: October 2013

Calibrated far-field pressure measurements of violin radiation excited by force hammer impact at the G-string corner of the bridge were performed at 266 microphone positions over an r=1.2 m spherical surface inside an anechoic chamber. These were combined with simultaneous mobility measurements over the violin surface using a scanning laser to extract radiation efficiencies for violin normal modes below 4000 Hz. For favorable cases it was possible to compute experimental values for radiation damping, and the companion fraction of vibrational energy lost to acoustic radiation. As an example, preliminary results for the lower of the first corpus bending modes of a violin by A. Schroetter were the following: radiation efficiency of ∼0.12, total damping of ∼1.15 (percent critical) for a Q of ∼43, radiation damping of ∼0.41 (percent critical). For this mode ∼35% of the vibrational energy was radiated as sound. Radiation patterns measured for each mode were corrected for anechoic chamber reflection/interference effects. [Research supported by the NSF DMR-9802656.]
An acoustical study on Lai vowel length
Authors: Vanbik Kenneth , Roengpitya Rungpat
Published: October 2013

Lai (Chin), a language from the Sino-Tibetan language family, has a contrastive vowel length. In this paper, the relationship between the vowel quantity and quality in Lai and the relative duration of these vowels and the following consonant were studied. The speech of an adult male native speaker of Lai, uttering in a frame sentence words having the shape /pVC/ where V was long and short versions of the five phonemic vowel qualities and C was either /t/ or /n/, was digitized. The F1, F2, and the duration of the vowels were measured as well as the duration of the final nasal. The data revealed that the long:short vowel duration ratio was about 2.5 for the tokens with a final stop and about 2.86 for the tokens with a final nasal. Vowels preceding a stop tended to be overall shorter than vowels preceding a nasal; final nasals after short vowels were significantly longer than after long vowels; short vowels were more centralized than long vowels. Thus although the vowels described as long:short are longer versus shorter, there are other correlated differences serving this contrast.
Effects of consonant aspiration on Mandarin tones
Authors: Xu Ching X. , Xu Yi
Published: October 2013

In this paper we present an experiment on the influence of consonant aspiration in Mandarin. A minimal pair, /da/ and /ta/, which differ only in aspiration, are produced in carrier sentences by native speakers of Mandarin. It is found that consonant aspiration affects the fundamental frequency (F0) of the following vowel. The onset F0 of a tone is higher following unaspirated consonants than following aspirated consonants, and the magnitude of difference is related to both the current and preceding tones. However, the later part of a tone tends to be lower following an unaspirated consonant than an aspirated one. These results seem to favor the speech aerodynamic model proposed by Ohala (1976), which predicts a smaller value of airflow at the onset of the vowel following an aspirated stop than an unaspirated one. The current results, however, seem to provide further details about the mechanism of the aerodynamic effect. Additionally, results of detailed analyses seem to suggest a possible source of the existing controversies over the exact effect of aspiration on F0. The discrepancy in the previously reported effects may be partially due to the difference in how the first few vocal cycles of the vowel are measured in different studies.
Dynamic center-of-gravity effects in consonant–vowel transitions
Authors: Jacewicz Ewa , Iyer Nandini , Fox Robert A. , Feth Lawrence L.
Published: October 2013

Lublinskaja has reported that dynamic changes in the spectral center-of-gravity (COG) of one formant in selected Russian vowels led to changes in the identification of the vowel. Movement of the COG was effected by simultaneous amplitude modulation of two formants placed at the end points of the desired frequency transition [Iyer et al., J. Acoust. Soc. Am. 109, 2294 (2001)]. The present study explores whether such COG effects will extend into the processing of consonant–vowel transitions (CVs). A [dɑ]–[gɑ] continuum was generated using a Klatt synthesizer with a 50-ms CV transition and a 200-ms vowel. The onset of F3 varied from 2018–2818 Hz in 80-Hz step. The F3 of the vowel remained constant at 2527 Hz. Three different stimulus sets differed in terms of whether the F3 transition was a: (1) formant, (2) FM tone, or (3) virtual frequency (VF) glide. In the VF stimuli, the frequencies of two tones matched the onset or offset frequencies of the F3 transition and modulation of their amplitudes produced a gliding spectral COG. Preliminary results indicate that listener performance is not strongly affected by changing the means by which spectral changes to F3 are made. [Research supported by a grant from OSU’s College of Social and Behavioral Sciences to L. Feth and an INRS award from NIH to R. Fox.]
The Center for Subsurface Sensing and Imaging Systems (CenSSIS): Addressing the challenge of implementing a strategy of ‘‘diverse problems similar solutions.’’
Authors: Silevitch Michael
Published: October 2013

CenSSIS has recently been designated by the National Science Foundation as an Engineering Research center (ERC). The CenSSIS mission is to unify the methods and tools used to detect and image biomedical and environmental–civil objects or conditions that are underground, underwater, or embedded in the human body. In the area of physics based signal processing and image understanding, methods of multiview tomography play a key role. Beginning with a brief description of CenSSIS, this talk will then focus upon a discussion of a unified framework that tries to articulate a methodology for characterizing end to end subsurface sensing and imaging problems. Several examples will be used to illustrate the ideas, including ones dealing with acoustic tomography.
Speech privacy in closed offices: Comparison of languages and accent
Authors: Ma Yong , Caswell Daryl J. , Goodchild Jim T. , Dai Liming
Published: October 2013

Up to now, most objective assessments for speech privacy and speech intelligibility, such as articulation index (AI), speech intelligibility index (SII), early-to-late sound ratio (Clarity), and speech transmission index (STI), are evaluated by subjective measurements primarily based on studies that incorporate only the English language. In today’s multicultural environment, it is necessary to study the impact on speech privacy of different languages and accents. In this work, subjective measurements were conducted in closed offices by using English, Mandarin Chinese (a tonal language), and accented English. Both close-set and open-set test materials, including single words, sentences, and articles were employed in the measurement. The results revealed the evaluation differences in speech privacy between two languages, as well as between native English and accented English. The subjective measurement results were also compared with the objective measurement indices AI, STI, and Clarity.
A comparison of visual and acoustic marine mammal monitoring methods
Authors: Frankel Adam S. , Vigness-Raposa Kathleen
Published: October 2013

Concern about the potential effect of increased oceanic noise on marine mammals has led to the consideration of a variety of at-sea marine mammal monitoring methods. A recent marine mammal survey utilized both visual observation and passive acoustic monitoring. Visual observations were conducted using 7×50 binoculars during the day and generation III night vision devices (NVDs) at night. Acoustic data were collected with a towed hydrophone array and analyzed with a customized, PC-based acoustic workstation. Seventy-seven visual sightings were made. Forty sightings were made at night and 37 were made in daylight. The effective range of the NVDs was estimated through observations of a target at known distances; 50% detection rating was achieved at 130 m. There were 98 acoustic detections. Of the 77 visual sightings, 42 were also detected acoustically. Six sightings were made without comparable acoustic detection, and 19 sightings were made when there was no acoustic monitoring. Conversely, 56 acoustic detections were made without visual sightings. These data suggest that, for species that commonly vocalize, a combined acoustic/visual survey will increase detection probabilities. Furthermore, night vision devices have the potential to be an effective observation tool for marine mammals. [Work sponsored by ONR.]
Interactions of Florida manatees (Trichechus manatus latirostris) with simulated fishing gear and a pinger: Implications for preventing entanglements
Authors: Bowles A. E. , Alves C. , Anderson R. A.
Published: October 2013

Nine stranded, rehabilitated and captive-born Florida manatees (Trichechus manatus latirostris) were exposed to simulated crab-pots and gillnetting to quantify interactions (70 trials). A pinger (Dukane–Seacom Netcom 1000, 300 ms ping at 4 s intervals, level ∼130 dB re 1 μPa from 10 to 80 kHz) was presented with and without the crab pot during 7 of the trials. Manatees were observed for 30 min (baseline), then exposed to the object for 30 min. During exposures, they manipulated objects extensively, with little or no evidence of neophobic avoidance. Most contacts (70%) were made with the mouth; the remainder involved the pectoral flippers, body, and paddle. Entanglements sufficient to require human intervention occurred in four trials. Manatees spent 36% more time in the test area when objects were present than during baseline trials, indicating a positive motivation to manipulate. The pinger stimulated brief startle reactions in two of four female manatees but in none of five males. Crab pots with pingers were contacted as much as the simulated crab pot alone (51% vs 41% by females). This motivation to manipulate suggests that manatees cannot be protected from fishing gear by pingers.
Characteristics of turbulence in the surf zone
Authors: Trowbridge John , Elgar Steve
Published: October 2013

Near-bottom measurements from an array of acoustic Doppler velocimeters over a sand beach produce direct estimates of turbulent shear stress, by means of a differencing procedure that rejects contributions from surface waves, and indirect estimates of dissipation, by means of an inertial-range model. Measurements of winds, waves, and currents provide a context for analysis of the turbulence measurements. The analysis focuses on an alongshore momentum equation, semiempirical relationships between turbulent shear stress and alongshore velocity, and simplified budgets for energetics. The records are dominated by three events when the instruments were in the surf zone. Near-bottom turbulent shear stress was well correlated with, but smaller than, the sum of wind and wave forcing. Vertical gradient of alongshore velocity was larger than indicated by the Prandtl–Karman law of the wall. Drag coefficient was smaller during breaking waves than during unbroken waves. Shear production of turbulent kinetic energy was approximately equal to dissipation, and both were two orders of magnitude smaller than the depth-averaged rate at which the shoaling wave field lost energy to breaking, indicating that breaking-induced turbulence did not penetrate to the seabed.
Measurements of turbulence in the wave boundary layer using high frequency acoustics
Authors: Terrill Eric , Gray Ronan , Melville Ken
Published: October 2013

The properties of the turbulent boundary layer at the air–sea interface exhibits departures from classical wall bounded shear flows as a result of the free surface characterized by surface waves. As surface waves grow in the presence of wind, they become unstable and break, which leads to the injection of turbulence and bubbles into the water column. While an understanding of these physical processes is critical to fields of oceanography and mid-/high-frequency ocean acoustics, there remains much to be learned due in part to the difficulty of obtaining turbulence measurements at the air–sea interface as well as signal processing issues associated with separating turbulent water motions from wave orbital motions. One maturing solution to this measurement problem is the use of O(1) MHz pulse to pulse coherent Doppler sonars that allow direct wave number measurements in the inertial subrange of the turbulence. Recent field measurements of near-surface turbulence have been conducted by our group with this sonar technology both offshore Pt. Conception California and Hawaii. Measurement results will be discussed, including observations regarding the relationship between the intermittancy of the turbulent dissipation to the overlying surface wave field. [Work supported by ONR and NSF.]
Observations of turbulence in ocean wave boundary layers
Authors: Stanton Timothy P.
Published: October 2013

A bistatic geometry, coherently sampled, acoustic Doppler profiler has been developed to measure turbulent stresses in wave-forced ocean boundary layers. The profiler is typically configured to measure over-resolved profiles of three-component velocity vectors sampled in O(2 cm3) sample volumes at 20 Hz over a 60 cm range above the ocean bed. Examples of bottom boundary layer observations made at Duck, NC and Monterey, CA during two field experiments illustrate approaches to measuring Reynolds stresses and shear in thin oscillatory boundary layers over a rippled bed. During the ONR-funded Shoaling Waves Experiment (SHOWEX) the profiler was mounted on an instrumented frame at 12 m depth and continuously measured velocity profiles and changes in wave-induced bed morphology through a succession of storms over a two month period. In the second example, observations of mean currents, wave-induced velocities, and turbulence were made in the surf zone just offshore from a steep-sloping beach.
Three variations on a theme: Ultrasound permeabilization of biologically interesting membranes
Authors: Mourad Pierre D.
Published: October 2013

This presentation focuses on three applications of therapeutic ultrasound for the purpose of permeabilizing membranes, with an emphasis, where possible, on the biology as well as the physics of the processes involved. In the first instance, ultrasound successfully and transiently opens the blood-brain barrier to the flux of blood-borne chemical dyes in vivo, as documented grossly, and with light and electron microscopy. In the second example, ultrasound transiently disrupts the membrane coating of a novel biopolymer tablet in vitro in order to release insulin carried within the tablet. The membrane consists of a series of self-assembling monolayers. In the final example, ultrasound acts synergistically with a novel polymer to permeabilize model lipid bilayers. The novelty here is that the effect is pH-dependent, due to the pH-dependence of the conformation of the polymer, and, that the polymer can be both targeted to cell surfaces with appropriate receptors, and can carry drugs or DNA. [Work supported by NIH and DARPA. I would like to thank my colleagues at CIMU and the Department of Neurological Surgery for their support in this work.]
Therapeutic applications of microbubbles
Authors: Unger Evan C. , Matsunaga Terry O. , McCreery Thomas P. , Sweitzer Robert , Schumann Patricia , Quigley Rachel , Zutshi Reena
Published: October 2013

While microbubbles have been developed for diagnosis as ultrasound contrast agents, the greatest potential of these agents may lie in therapy. Microbubbles have extensive applications for treating vascular thrombosis, drug and gene delivery. Targeted microbubbles containing ligands for cell or site-specific recognition have been developed. These agents function like ‘‘smart bubbles’’ to home in on their targets. One such agent, MRX-408, a microbubble bearing targeting ligands directed to the activated receptor of platelets has undergone extensive pre-clinical testing. Recent studies comparing Sonothrombolysis with MRX-408 and nontargeted microbubbles show significantly more clot lysis with targeted as compared to nontargeted microbubbles. The targeted bubbles effectively concentrate cavitation nuclei within the clot. Additional targeted microbubbles for drug and gene delivery are also under development.
Modal analysis of steelpans: Holographic, computer, sand patterns, and microphone scannning
Authors: Hansen Uwe J. , Rossing Thomas D.
Published: October 2013

We compare several methods for modal analysis that have been applied to Caribbean steelpans. Holographic interferometry offers the best spatial resolution of operating deflection shapes, and hence of normal modes. Recording holographs on photographic film tends to be rather time consuming, however. Electronic TV holography, on the other hand, offers the opportunity to observe vibration motion nearly in real time. Striking a steelpan with an instrumented force hammer excites many modes at once, and a computer program is used to determine the normal modes by means of a curve-fitting program. In the oldest method of modal analysis (and still a useful one), a fine powder is sprinkled on the surface of a steelpan vibrating at the frequency of a given mode. The powder collects at the nodal lines, providing a Chladni pattern or map of that mode.
Determination of reference sound source sound power levels using ARI Standard 250
Authors: Lind Stephen J.
Published: October 2013

The Air Conditioning and Refrigeration Institute (ARI) Standard 250 Performance and Calibration of Reference Sound Sources was used to establish one-third octave band sound power levels of several reference sound sources (RSS). The work was carried out in an anechoic chamber that was qualified at frequencies of 100 Hz and above using ANSI S12.35. Measurements were made with circular slices around the RSS at heights from 5 cm to 195 cm in 10 cm increments using both intensity and sound pressure. A 19 point fixed array was also employed for comparison of one of the sources. Sound power levels were compared from the 50 Hz to the 10000 Hz one-third octave bands using several methods. The results are compared to the sound power levels provided by the manufacturer.
Broadband passive noise control in air/water using structural acoustic silencers
Authors: Ramamoorthy Sripriya , Cook William P. , Grosh Karl , Nawar Tony G.
Published: October 2013

The effectiveness of introducing flexible structural layers into fluid and air conveying ducts for controlling noise is investigated through theoretical and experimental means. Previous work has shown that using flexible rather than rigid walls can theoretically achieve high transmission losses. However, for hydraulic applications these relatively thin layers cannot sustain the high static pressures seen in real situations and for pneumatic applications, radiated noise from these walls (called breakout noise) is a significant issue. Designs that introduce a second duct below the flexible wall region of the main duct allows for equilibration of the static pressure and elimination of breakout noise. However, plane waves can now propagate through the duct without exciting the plate, thus reducing the effectiveness of the device. Designs suitable for hydraulic/pneumatic applications, that overcome these issues and achieve appreciable transmission loss are investigated. Results based on 2.5 D finite element simulations will be compared with experimental results. [Research funded by ONR and NSF.]
The use of parallel-plate regenerators in thermoacoustic-Stirling engines
Authors: Backhaus Scott , Swift Gregory W.
Published: October 2013

The regenerator is a key element in a thermoacoustic-Stirling engine. Typically, it is made by stacking up many layers of fine-mesh stainless-steel screen. With a high heat capacity and a typical pore size much smaller than the thermal penetration depth, it provides a nearly isothermal environment at the acoustic frequency. By almost eliminating the temperature oscillations of the gas in it, the regenerator minimizes the unwanted enthalpy flux from the hot heat exchanger to ambient heat exchanger and keeps the engine’s efficiency high. However, the small pore size also causes a significant amount of viscous dissipation, which lowers the efficiency. A regenerator made of parallel plates can be designed to provide the same heat transfer properties as a screen regenerator with much lower viscous dissipation. By replacing a screen based regenerator with a carefully constructed parallel-plate regenerator, the acoustic power output of a thermoacoustic-Stirling engine is nearly doubled, with significant increases in efficiency at high amplitudes. [Work funded by the Office of Basic Energy Sciences within the U.S. DOE.]
A method for the automatic hearing aid fitting employing speech in noise and fuzzy logic
Authors: Kostek Bozena , Czyzewski Andrzej
Published: October 2013

Some limitations of the hearing aid fitting process are discussed. The classical procedures in this process are based on audiometric test results and/or the loudness scaling method employing artificial test signals. However, the fitting of hearing aids should be also performed on the basis of testing speech understanding in noise, because this is much closer to the real life conditions. A satisfying reliability of these tests may be achieved through the use of modern computer technology with an application of a properly calibrated sound system. A new strategy applicable to fitting prostheses was developed. It allows finding automatically characteristics of a hearing aid matching patients needs. The principles of the fitting method employing fuzzy reasoning, and some results of the experiments will be presented in the paper.
High-frequency stimulation in tinnitus treatment
Authors: Lenhardt Martin L. , Richards Douglas G. , Madsen Alan G. , Shulman Abraham , Goldstein Barbara A. , Guinta Robert
Published: October 2013

Limited but convincing evidence suggests neural plasticity plays a role in the development and maintenance of tinnitus. Tinnitus is generally pitch matched with high frequencies (<6 kHz) and is often associated with very hearing loss, although the conventional audiometric thresholds may be normal or near normal. It is hypothesized that the brain experiences high-frequency air conduction auditory deprivation and this is a causative factor in tinnitus. If the low-pass middle ear is circumvented by bone conduction stimulation, residual high-frequency receptors in the cochlea can again be activated. High-frequency bone conduction transducers were fabricated to deliver frequencies from 6 to 40 kHz. The transducers were aluminum ceramic bimorphs with circular topology which were heavily damped by mass loading to the mastoid with resonances at 9 and 39 kHz. Ten subjects with persistent tinnitus were selected to listen to proprietary high-frequency patterned stimulation for two half-hour sessions for 4 weeks. Exit questionnaires revealed satisfaction with tinnitus relief in the majority (60%) with residual inhibition lasting on the order of weeks (mean=1.5 weeks). Encouraged by these findings, more extensive trials are underway to explore the efficacy of high-frequency bone conduction treatment in central tinnitus.
Structural damping as a result of piezoelectric energy harvesting
Authors: Lesieutre George A. , Hofmann Heath , Ottman Geffrey
Published: October 2013

This paper describes an approach to harvesting electrical energy from a mechanically-excited piezoelectric element. If the piezoelectric element is attached to a vibrating structure, this energy transfer also results in structural damping. The energy harvesting approach is loosely based on the fundamental electrical engineering concept of optimal loading. The harvesting circuit consists of an ac–dc rectifier with an output capacitor, an electrochemical battery, and a switch-mode dc–dc converter that controls the energy flow into the battery. An adaptive control technique was initially used to vary the switching duty cycle so as to maximize power transfer into the battery. Experiments demonstrated that the adaptive dc–dc converter increased power transfer by over 400%, as compared to direct connection of the rectifier output to the battery. For persistent excitation above a certain level, the existence of a near-optimum duty cycle was also observed. A standalone energy harvesting system that exploited this observation was developed. This system has two modes: for low excitation, the rectifier charges the battery directly; while for higher excitation, the battery runs a fixed duty cycle dc–dc converter. This standalone system was successfully demonstrated in the laboratory. Effective damping loss factors associated with this energy harvesting scheme are also reported.
Analytical solutions for characterizing tortuosity and characteristic lengths of porous materials using acoustical measurements: Extrapolation model
Authors: Panneton Raymond , Olny Xavier , Tran Van Jerome
Published: October 2013

Following sophisticated descriptive models on sound propagation in porous media, five acoustical parameters usually describe the complexity of the porous network: porosity, static air flow resistance, tortuosity, and viscous and thermal characteristic lengths. While porosity and airflow resistance can be measured directly and accurately using simple apparatuses, simple and accurate direct measurements of the tortuosity and characteristic lengths are still an open research area. Actual researches on the characterization of these parameters use acoustical methods in the ultrasound frequency range. In this paper, a similar approach is investigated, but applying this time in the frequency range 2000–6000 Hz. The method is based on analytical solutions linking the tortuosity and characteristic lengths to measured dynamic density and compressibility. Following an extrapolation procedure to infinite frequency, the tortuosity and characteristic lengths are deduced without prior knowledge of porosity and air flow resistance. Experimental results from Kundt’s tube are compared to simulations on various materials to show the accuracy and limitations of the method.
Bilingual speech production: The case of simultaneous acquisition
Authors: Sundara Megha , Polka Linda
Published: October 2013

Despite increased interest in people learning a second language (L2) in the past decade or two, there have been few studies investigating production by bilinguals at the segmental level. In this experiment coronal stop consonants in real-word productions in French and English by bilingual French–English speakers, very fluent in both languages having learned the two languages simultaneously since birth, were recorded. Differences in the phonetics of Canadian French and English include VOT and place of articulation distinctions. Canadian French has a two-way voicing distinction between prevoiced and simultaneous release stops and uses the dental place of articulation. Canadian English, on the other hand, has a two-way voicing distinction (in syllable initial position) between simultaneous and aspirated release for stops and uses an alveolar place of articulation. Acoustic analyses of stop consonants for both VOT and place of articulation (dental versus alveolar) are reported. Productions by bilinguals will be compared with those of respective monolingual groups for similarities and differences. Results will be discussed with respect to Grosjean’s wholistic-fractionated classification of the bilingual system [F. Grosjean, Brain and Language 36, 3–15 (1989)].
Characteristics and intelligibility of Japanese-accented English
Authors: Nishi Kanae
Published: October 2013

The relationship between intelligibility and the degree of accentedness of Japanese-accented English was studied using an accentedness rating task, an identification task, and multidimensional scaling (MDS). Native speakers of American English (AE) listened to speech samples of 270 AE monosyllable words recorded by three groups of speakers (native AE, Japanese residing in the United States, and Japanese who had never lived outside Japan). The length of stay in the U.S. was positively related to native-like dimensionality in MDS solutions and the correct identification of words, but unrelated to ratings of foreign accentedness. High intelligibility was not necessarily achieved by less-accented speakers but by speakers with well-differentiated dimensional structures.
Native and non-native perception of phonemic length contrasts in Japanese
Authors: Kato Hiroaki , Tajima Keiichi , Akahane-Yamada Reiko
Published: October 2013

Segment length is distinctive in Japanese, e.g., /kado/ ‘‘corner’’ versus /ka:do/ ‘‘card,’’ unlike languages such as English. To study this property extensively and precisely, a series of perception experiments were conducted. Stimuli were pairs of unaccented 3- or 4-mora nonsense Japanese words of the basic form /ere——e/ where —— is one of /p t k m n s/. Each pair contrasted in either vowel length, e.g., /erete/ versus /ere:te/, or in consonant length, e.g., /erete/ versus /erette/. Each pair was also embedded within a carrier sentence. A synthetic continuum gradually varying in the duration of the target vowel or consonant was built for each pair using straight, a high-fidelity speech analysis, synthesis, and manipulation system [Kawahara et al., Speech Commun. 27, 187–207 (1999)]. Native Japanese and native English speakers participated in both identification and discrimination tests of each continuum. Preliminary results from stimuli containing stops indicate that the non-native discrimination scores were significantly poorer than the native scores, particularly when the continua were embedded in a sentence. The non-native identification scores, however, were similar to those of the native. Implications of these findings are discussed along with results from the fricative and nasal continua.
Brain plasticity in behavioral and neuromagnetic measures: A perceptual training study
Authors: Zhang Yang , Kuhl Patricia K. , Imada Toshiaki , Kotani Makoto , Pruitt John
Published: October 2013

The present study investigated brain plasticity in Japanese adults learning the English /l–r/ distinction. Both behavioral and brain (MEG) measures were used. Training was designed to mimic the listening experience of infants who are exposed to the exaggerated acoustic events contained in infant-directed speech (‘‘motherese’’). A multimedia software program incorporated major features conducive to perceptual learning. The program consisted of 12 1-h training sessions. Pre- and post-training measures were collected from nine subjects including two controls. The MEG experiments examined training effects in preattentive discrimination versus categorization conditions. An average improvement of 21.7% was obtained behaviorally. The training effect was significant for all factors of speaker, vowel, and syllabic context. Perceptual learning generalized to three untrained voices. No effects were observed in the two control subjects. Consistent with the behavioral results, the MEG data showed significantly improved mismatch responses in the left hemisphere. Both behavioral and brain data indicated that the learned phonetic boundary in Japanese subjects did not match that of the American listeners. This pattern of results suggests the existence of substantial neural plasticity in adulthood as well as a potential limit. [Work supported by NIH, HFSP, and the Talaris Research Institute.]
Effects of short-term exposure to a foreign language on discrimination of a non-native phonetic contrast: Convergent evidence from brain and behavioral tests
Authors: Kuhl Patricia K. , Tsao Feng-Ming , Liu Huei-Mei , Corina Sharon , Stevens Erica , Nelson Tobey , Pruitt Jessica , Padden Denise
Published: October 2013

Studies in our laboratory demonstrate that between 6 and 12 months of age infants show a significant increase in the ability to discriminate native-language phonetic contrasts and a decline in foreign-language discrimination. The increase in performance on native-language contrasts suggests a process of active learning rather than maintenance. In the present experiment, we tested whether the learning process infants engage in during the period between 6 and 12 months extends to a foreign language the infants had not previously heard. American infants at 9 months of age participated in a 12-session language play group in which they heard a native speaker of Mandarin Chinese read, play, and talk to them. A control group was exposed to American English using the same books and toys. Both groups were subsequently tested on a Mandarin Chinese contrast using both behavioral and brain measures. The results demonstrate that infants exposed to Mandarin over a 4-week period show significant discrimination of the Mandarin contrast measured both behaviorally and with event-related potentials (ERP). The data, demonstrating that short-term exposure to language results in significant increases in performance, suggest a powerful learning process in language acquisition. [Research supported by NIH, HFSP, and the Talaris Research Institute.]
Word segmentation in a foreign language: Further evidence for crosslinguistic strategies
Authors: Hoehle Barbara , Giesecke Dorothee , Jusczyk Peter W.
Published: October 2013

We report further evidence that early word segmentation is triggered by rhythmic properties of the language. Our study used the head turn preference paradigm to compare the skills of English and German 9-month-olds to extract bisyllabic trochaic German words from German text passages. Both English and German are stress-timed languages and have trochaic feet as their dominant stress pattern in bisyllabic words. Consequently, no differences in the segmentation strategies used by infants from these two language groups were expected. In line with our predictions, even though the stimulus material contained phonemes that do not belong to the English phoneme inventory and violations of English phonotactics, English-learners were as successful in detecting the words as German infants. These findings replicate those of Houston et al. (2000) with Dutch and English. Thus, our findings provide further evidence that children can exploit processing strategies developed in their own language to process another language. Furthermore, the data suggest that, at least initially, word segmentation in infancy relies on acoustical information in a pure bottom-up fashion without the support of existing knowledge about the language to be processed.
Eye movements and the activation of native words in non-native spoken-word recognition
Authors: Weber Andrea
Published: October 2013

Using the eye-tracking paradigm, this study explored the recognition of non-native spoken words. In particular, it focused on whether listeners activate native candidate words during the recognition of non-native words. Dutch participants followed spoken instructions in English to click on pictures using a computer mouse, while their eye movements were monitored. A target picture (e.g., the picture of a desk) was presented along with distractor pictures. The Dutch name of a distractor picture was either phonologically related to the English name of the target picture (e.g., English target desk /dEsk/ and Dutch competitor deksel, ‘‘lid,’’ /dEks@l/) or it was phonologically unrelated (e.g., bloem, ‘‘flower’’ or schommel, ‘‘swing’’). Eye movements to a picture were interpreted as evidence for activation of the lexical representation associated with this picture. As the English target word unfolded over time, participants fixated distractor pictures with phonologically related Dutch names more than distractor pictures with phonologically unrelated names. The results demonstrate that listeners consider candidate words of the native language for recognition of a non-native word. Listeners are not able to deactivate the native mental lexicon even when they are in a monolingual non-native situation where the native language is irrelevant and possibly even misleading. [Work supported by MPI for Psycholinguistics.]
Chemical sound absorption in the ocean
Authors: Fisher Frederick H.
Published: October 2013

Two salts cause significant sound absorption in the ocean, small concentrations of magnesium sulfate ion pairs and boric acid. Below 100 kHz, MgSO4 produces sound absorption ∼30 times greater than that of pure water. For boric acid below 1 kHz, the excess absorption in the Atlantic over pure water is ∼300 times and in the Pacific ∼150 times, the difference being lower pH at the sound axis in the Pacific than in the Atlantic (7.7 vs 8), the borate concentration being the same. For MgSO4, a four state dissociation model of Eigen and Tamm provides an explanation of sound absorption at 1 ATM from 10 kHz to 300 MHz. Remarkably, at 1000 ATM, this same model accounts for the observed large decrease in sound absorption (−66%) and the small increase in electrical conductance (+10%). For boric acid, Simmons explained absorption in terms of a three state ion pair model involving a configurational change of the B(OH)4 ion from a tetrahedral to a planar trigonal structure B(OH)3 involving a large volume change of 36 cm/mole. The discovery, some history and the current status of these once ‘‘anomalous’’ absorptions will be discussed. [Work supported by ONR and NSF.]
Using signal processing in real-time trumpet performance
Authors: Plsek Thomas J. , Brantigan Daniel
Published: October 2013

The real time use of signal processing for trumpet instrument performance provides an opportunity, as well as challenges, to create a type of hyper-instrument quite unlike most conceptions of the term. These include the expansion of the available sound palette, the problem of real-time parameter control, microphone techniques, and repertoire considerations. The various types of processing used includes reverb, pitch change, delays—short time and longer looping types, distortions, and combinations of the above. Normally, the processed signal is layered onto the acoustical output of the instrument, but by using such devices as the Yamaha Silent Brass one can diminish the presence of the acoustical signal of the instrument in the final output. By creatively managing the acoustic instrument and the electronic equipment, a vast array of musical resources become available to the performer enabling him/her to enhance existing performance environments, as well as find and develop new ones.
History of acoustical oceanography
Authors: Spindel Robert C.
Published: October 2013

This lecture traces the history of acoustical oceanography from its beginnings during WWII (although it was not called Acoustical Oceanography at the time) to the present. We describe how during the Cold War the U.S. and Soviet Navy’s efforts to improve the performance of their torpedoes and sonars revealed unknown ocean features and processes. We discuss the prominent role of the U.S. Navy’s Office of Naval Research in bringing underwater acoustics and oceanography together, and fostering the science upon which Acoustical Oceanography is based. We show how the two fields eventually fused into a new discipline called Acoustical Oceanography, and how that combination has resulted in today’s acoustic methods for observing the ocean on micro, regional, and global scales.
Diffracting open-ended duct of finite length: flow effects
Authors: Martinez R.
Published: October 2013

Dr. Junger once addressed the problem of diffraction by ducts of finite length using a variational approach that supplied an approximate solution (personal communication, ca. 1986). His medium was quiescent. The speaker later tackled the problem numerically and more rigously [J. Acoust. Soc. Am. 87, 523–531 (1990)], and provided an a posteriori check on that new solution via number of power-related quantities. The current presentation extends our earlier analysis to include the effects of a freestream on the acoustics of a free-flooded unbaffled duct, which in this context becomes a ring wing insonified from within. The theory’s physical content includes the ring wing’s shed and trailed vorticity systems, which are formally coupled to the acoustic field over the duct’s surface. The presence of vorticity makes the standard boundary-element approach numerically unstable for reduced frequencies of O(10) (reduced frequency being Strouhal number based on the ring wing’s half-length). Our solution technique restores numerical stability through a reformulation of unsteady lifting-surface theory to be a Fredholm integral equal of the second kind. The presentation concludes with general remarks on diffraction theory for thin two-sided objects, particularly on the use of reciprocity in the calculation of diffracted nearfields for soft screens.
The evolution of test instrumentation: From rack and stack to plug and play
Authors: Alexander Martin
Published: October 2013

Electronic test instrumentation for acoustics and vibration measurement has seen radical changes during the final decade of the 20th century. From analog to digital to PC based, the performance, flexibility and ease of use have risen while the price per performance has declined. Taking advantage of the rapid developments in PC operating systems, mass marketed microprocessors, and the professional audio industry, todays instrumentation frequently has more in common with both the recording studio and the home computer than with the physics laboratory. The future promises even more as this evolution continues. Two examples, vehicle vibration analysis and electroacoustic testing, are used as examples to follow the development of test platforms. The advantages (and disadvantages) of software-based testing are discussed, and some insights of what the new decade might offer are provided.
Sound absorption in titanium at 25 kHz
Authors: Fisher F. H. , Hsu C. C.
Published: October 2013

In the process of studying sound absorption in magnesium sulfate solutions as a function of pressure, a 100 L titanium sphere (a spare ballast tank for the WHOI researc submarine ALVIN) was used up to 300 atm. In calibrating the losses due to the sphere with pure water, Hsu found a resonant mode at 25 kHz (using a HP microHz synthesizer) with a very long decay at 1 atm and 25°C; a straight line 50 dB decay of 70 s. This means that ultrasonic absorption in the titanium sphere (4 Al, 6 Va alloy) filled with water is 5.5exp(−7) N/cm. This is four times greater than that of water at 25 kHz. Therefore, subtracting the absorption of water yields an upper limit for absorption in titanium of 4.1exp(−7) N/cm. The 0.9 m sphere was suspended from two loops of piano wire in a steel vacuum chamber. The resonance (Q=955000) required considerable attention to insuring pressure, temperature, and frequency control, as well as the usual degassing of the liquid. Discussion of results and details will be presented. [Research supported by ONR.]
Propagation of acoustic waves through finite solid superlattices
Authors: Manzanares-Martinez Betsabe , Ramos-Mendieta Felipe
Published: October 2013

The transmission of longitudinal waves through solid superlattices is studied. The waves income from a fluid or a solid and the transmission medium is a fluid. It is found that the transmission spectrum is closely related to the free-stress surface vibrational modes in the superlattice slab. The correspondence of the transmission peaks with these modes is better when the impedance contrast between the external medium and the superlattice is high. Results for normal and oblique waves in a superlattice of Al/W embedded in Hg, water, or air are presented. As the impedance of the external medium changes it is found new minigaps for the wave transmission inside the allowed frequency region for bulk propagation. Additional structure to the transmission spectrum is produced by localized excitations. Transmission with frequencies in the gap is assisted by the occurrence of surface waves and enhanced transmission is observed inside the frequency bands due to the presence of surface resonances. Theoretical results for a Pt/W superlattice are presented. B.M-M. is grateful to CONACyT Mexico, for a doctorate scholarship. [Work supported by CONACyT Mexico, Grant No. 35541-E.]
Infants use of visual information in speech segmentation
Authors: Hollich George J. , Jusczyk Peter W. , Newman Rochelle S.
Published: October 2013

What are infants abilities to segment the running stream of speech in a noisy environment? Infants often find themselves in situations far louder and more complex than the acoustic isolation chambers and minimalist rooms of traditional infant testing. The current series of studies used the headturn preference procedure (with video familiarization) to examine 7.5-month-old infants abilities to use visual/auditory correlations to reliably segment a given speech stream in the face of a distracting voice. Results indicated that infants gained a 10-dB advantage when the visual display matched the acoustic passage. That is, when two blended voices were of equal loudness, infants could use visual correspondences to reliably recognize words presented in the matching video. In contrast, in cases where the target voice was 5 dB softer than the distracting voice or a static picture of the face was presented, infants did not show an ability to segment the speech stream.
Coarticulation in dysarthria
Authors: Tjaden Kris , Kozak Alexa , Kleinhaut Jessica
Published: October 2013

The dysarthrias are a group of speech disorders resulting from impairment to nervous system structures important for the motor execution of speech. Numerous studies have examined how dysarthria impacts articulatory movements and the resulting changes in vocal tract shape. Few studies of dysarthria, however, consider that articulatory events and their acoustic consequences overlap or are coarticulated in connected speech, although coarticulation has been studied extensively in neurologically normal speakers and figures prominently in normal speech production theories. In so far as coarticulation presumably would have a similar status in a speech production theory of dysarthria, further investigation of coarticulatory patterns in dysarthria appears warranted. The current study will examine intersyllabic, anticipatory vowel-to-vowel coarticulation in normal speakers, and speakers with Multiple Sclerosis, a disease characterized by plaques in the white matter of the CNS. The speech sample consists of 3 repetitions of 16 target words in the phrase ‘‘It’s a____________again.’’ Phrases were produced in normal, loud, and slow speaking conditions. The effect of target word vowels on /ə/ in the word ‘‘a’’ will be inferred from F2 measures. Within conditions, coarticulatory differences will be compared for MS and Control speakers. Coarticulatory differences across speaking conditions also will be examined.