bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasound-mediated nail drug delivery system to treat fungal disorders.
Authors: Abadi Danielle , Zderic Vesna
Published: March 2010

This physiotherapy device treats nail fungal disorders by improving drug delivery to the nail bed using low frequency ultrasound to increase the permeability of the nail. Applying therapeutic ultrasound to the nail will allow pits to form on the surface through which more of the topical drug can be delivered. Transducers with corresponding matching networks are constructed in-house from 300-kHz and 1-MHz piezoelectric crystals. A software interface allows patients to select which toes to treat and at what intensity level (high, medium, or low). The highest-intensity setting supplies 1.5 W/cm2 for a duration of 30 s to prevent damage to tissue below the nail. The software interface sends information to the electrical driving system,which is composed of an amplifier for each intensity level and a signal generator. A Franz diffusion cell setup in combination with a spectrophotometer is used for experimental testing of nail permeability by measuring the amount of drug delivered through the membrane. Animal nails are used as a human nail model, and both drug-mimicking dye and Penlac (a topical prescription drug) are used for testing.
On the concept of transient directivity: Pipes and horns.
Authors: Tengelsen Daniel , Anderson Brian E. , Leishman Timothy W.
Published: March 2010

Directivity is a convenient way to represent how sound radiates from some arbitrary object in steady-state. The steady-state condition is implied when time harmonicity is assumed. Because all physical systems do not begin in steady-state, this directivity measurement is only valid after the transient portion of the solution has decayed. Transient directivity—a measure of sound radiation versus angle at a given instant in time and before the system has reached steady-state—is presented. Understanding an object’s transient and steady-state radiation characteristics may be important in understanding the sound radiation from sources that are transient in nature. Results of transient directivity will be presented for pipes and horns from both numerical models and experimental measurements.
Modeling of transducer arrays for direct digital-to-analog conversion of signals.
Authors: Amado Jose , Tkachov Nikita , Thompson Charles
Published: March 2010

A binary weighted array of speakers will be used to reconstruct a decomposed sequence of delta functions. The idea of directly converting digital signals to an analog acoustic output was first proposed by J. L. Flanagan in 1979, in which he designed, fabricated, and tested digital transducers for 4-, 5-, and 6-bit PCM signals. Flanagan found that at 6-bit resolution, the system fell short of good quality, and that condenser transducers had a limited output sound level of about 85 dB. Simulations will be used to investigate experimentally developed models for transducers and apply the direct digital-to-analog approach.
Head-tracking interface using a Wii remote.
Authors: Sunny Megha , Kalkan-Savoy Ayse , Thompson Charles
Published: March 2010

In this work, we will examine the problem of detecting the angular motion of head in effort to build a head-tracking system to control sound. The head motion occurs in X, Y, and Z linear directions and three rotation angles, namely pitch, roll, and yaw. In the past, we had difficulties to detect the rotation angles, especially yaw. Our current work focuses on the detection of rotation angles using a software interface program. The distance between sound source and head, and angular rotation data is collected by the Wii-remote’s built-in optical sensor and three-axis accelerometer. These real-time data will be used as input to our software interface. Results will be used in conjunction with head related transfer function to create the three dimensional sound source effects.
A preliminary analog circuit model of a balanced-armature transducer utilized for energy harvesting.
Authors: Smith Holly A. , Thompson Stephen C.
Published: March 2010

This research investigates a balanced-armature transducer’s potential to harvest ambient vibrational energy into electrical energy that could then be used to power small devices or recharge batteries. Such a device is desirable due to its compact size and environmentally friendly operation. An analog circuit model of a balanced-armature transducer was created in a version of SPICE. To ensure the model’s accuracy, the electrical impedance predicted by SPICE was compared to experimental measurements. The model was then adjusted for energy harvesting. [Work supported in part by the Office of Naval Research.]
Modified single crystals for high-power, broadband underwater projectors.
Authors: Sherlock Nevin P. , Meyer Richard J.
Published: March 2010

When operating high-power electromechanical devices, the performance is often limited by self-heating within the active material. This is especially true in high-power, broadband underwater projectors using the piezoelectric single crystal Pb(Mg1/3Nb2/3O3–PbTiO3 (PMN-PT). Although PMN-PT crystals show an excellent piezoelectric response (d33 > 1500 pC/N) and high-coupling coefficient (k33 > 0.90), device performance is limited by the high-mechanical losses (QM < 100) and low-temperature phase transformation (TRT = 95 °C). This work describes the material property enhancements of two compositional modifications and compares the performance of these crystals in high-power, broadband transducers. One such modification is the addition of Pb(In1/2Nb1/2O3 (PIN) or PbZrO3 (PZ) to the binary PMN-PT composition. The greater thermal stability of ternary PIN-PMN-PT and PZ-PMN-PT crystals is shown by comparing the dielectric permittivity, piezoelectric coefficient, and coupling coefficient to unmodified PMN-PT as a function of temperature. Additionally, the mechanical losses of PMN-PT have been decreased by doping with Mn3,4+ ions. Using a laser Doppler velocimeter, the losses are evaluated under increasing ac electric drive. Using these data, high-power, broadband projectors were constructed from these modified crystals, and the results are compared to a projector using unmodified PMN-PT. [Funded by ONR under N00014-07-1-0336.]
“Future faces of physics” and other initiatives to broaden participation in science.
Authors: O’Riordan Catherine , Rand Kendra
Published: March 2010

Together, Hispanic-Americans and African-Americans make up over 25% of the US population, but they earn only 7% of physics bachelor’s degrees. In order to help broaden the participation of underrepresented groups in STEM fields, the American Institute of Physics has several programs to work with students as well as to reach the general public. To engage physics undergraduates on the challenging subject of diversity, the Society of Physics Students (SPS), a society of over 4000 undergraduate physics students that is part of the American Institute of Physics (AIP), has launched two new programs. SPS has developed a Physics Jeopardy-like game as part of a “Future Faces of Physics” kit that includes various materials that help engage students in conversations about diversity. These kits have been used at more than 20 regional and national meetings since 2008 with positive results. AIP has also worked with Research Corporation to launch a program that brings Nobel laureates to HBCU’s and to SPS campus or regional events that include participation by Minority Serving Institutions. Another AIP program creates short TV science news segments and distributes them free of charge in Spanish. These programs and future directions will be summarized.
What faculty say, and convey, matters: Interactions with underrepresented students in science, technology, engineering, and mathematics.
Authors: Fries-Britt Sharon
Published: March 2010

Join us for this invited presentation as we examine students perceptions of their interactions with faulty. The participants in this study were primarily undergraduate students; however, approximately one-quarter of the participants were graduate students and post-doctoral research assistants. The entire sample consisted of students from a variety of postsecondary institutions including public and private, predominantly White, historically Black and Hispanic serving institutions from across the United States. This research is part of a larger study conducted over a 5-year period (2004–2009) with the National Society of Black Physicists (NSBP) and the National Society of Hispanic Physicists (NSHP). The majority are physics majors; however, some students are pursuing dual degrees in other STEM disciplines such as math, astronomy, and engineering. The findings of this study indicate that their interactions with faculty in the classroom and in advising session are critical. When those interactions are positive students benefit tremendously; however, in many instances they are negative and the interactions can cause barriers to their engagement in learning process and in how supported students feel pursuing science. Join us as we discuss some of the challenges and opportunities that these students encounter in their interactions with faculty.
Diversity in physics: Whose problem is this? What can I do?
Authors: Hodapp Theodore W.
Published: March 2010

Physics has one of the lowest participation rates for underrepresented minorities and women of all science, technology, engineering, and mathematics (STEM) fields. Things are improving for women and, while still not representative of the population, the trends are encouraging. Underrepresented minorities, however, have not been as fortunate. I will describe the current status of participation in physics and discuss new initiatives planned to address the lack of involvement at all levels in the field. In particular, I will describe a new program by the American Physical Society (APS) that aims to significantly increase the number of minorities who receive Ph.D.’s in physics. Actions you can take within your community, university, or workplace will be discussed. I anticipate a lively discussion during the panel that follows to bring forward good ideas and possible actions we can collectively take to improve participation of all people in physics and the technical workforce. The APS has partnered with leaders in the community to address these issues, and we hope that members of the Acoustical Society will find ways to work collaboratively to attend to these problems. This is our responsibility.
Vassar College-Bronx Institute acoustics workshop for low-income, ethnic minority, urban high school students.
Authors: Bradley David T. , Kelly Angela M.
Published: March 2010

Recent studies continue to show that low percentages of women and members of underrepresented ethnic groups are pursuing careers in science, technology, engineering, and math fields. Acoustics is no exception to this trend. As national demographics change more rapidly, and globalization transforms the way we approach the scientific process, the need for diversity becomes even more essential. The inclusion of women and minorities not only changes the questions being asked but also changes how those questions are answered. For acoustics to grow as a discipline, barriers to participation and success of members from underrepresented groups must be eradicated, and we must address the leakage in the science pipeline for students and professionals at all stages in their careers. One key area of concern is the recruitment and retention of K-12 students. This presentation will detail the joint efforts of the Vassar College Physics and Astronomy Department and the Bronx Institute at Lehman College to establish a hands-on, inquiry based acoustic workshop series for urban, low-income, underrepresented ethnic minority students from a collection of high schools in the Bronx borough in New York City.
High-pressure magnetically driven compression waves in condensed matter.
Authors: Davis Jean-Paul
Published: March 2010

The Z machine is a fast pulsed-power machine at Sandia National Laboratories designed to deliver a 100-ns rise-time, 26-MA pulse of electrical current to Z-pinch experiments for research in radiation effects and inertial confinement fusion. Since 1999, Z has also been used as a current source for magnetically driven, high-pressure, high-strain-rate experiments in condensed matter. In this mode, Z produces simultaneous planar ramp-wave loading, with rise times in the range of 300–800 ns and peak longitudinal stress in the range of 4–400 GPa, of multiple macroscopic material samples. Control of the current-pulse shape enables shockless propagation of these ramp waves through samples 1–2 mm thick to measure quasi-isentropic compression response, as well as shockless acceleration of copper flyer plates to at least 28 km/s for impact experiments to measure ultra-high-pressure (∼3000 GPa) shock compression response. This presentation will give background on the relevant physics, describe the experimental technique, and show recent results from both types of experiments. [Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract No. DE-AC04-94AL85000.]
Music on more than one note: Pitch perception and neural coding of concurrent harmonic tones.
Authors: Micheyl Christophe , Oxenham Andrew, J.
Published: March 2010

The basis of Western music lies in the combination of simultaneous (harmony) and sequential (melody) harmonic complex tones or notes. Listeners must “hear out” simultaneous pitches and “track” pitch sequences over time. Surprisingly few psychoacoustic studies have studied pitch perception under such “natural” conditions of more than one note at a time. Similarly, the neural mechanisms that support these abilities remain poorly understood. Here, we will review psychoacoustical and neurophysiological findings, which concur to suggest an important role for frequency selectivity in the ability of the auditory system to segregate concurrent notes. In particular, the ability to accurately discriminate changes in the fundamental frequency or, subjectively, pitch of a “target” harmonic complex tone in the presence of a “masker” tone occupying the same spectral region seems to covary with the limits peripheral frequency selectivity. Given that harmonic complex tones are an important class of sound for both music and speech and that frequency selectivity is usually adversely affected by cochlear damage, such results may have important implications for the current understanding of auditory scene analysis of concurrent music and speech sounds and of the listening difficulties experienced by hearing-impaired individuals. [Work supported by NIH Grant R01 DC05216.]
Imaging and inducing disorders in musical perception and production.
Authors: Loui Psyche
Published: March 2010

To perceive and produce music accurately, the brain must represent, categorize, plan, and execute pitched information in response to environmental stimuli. Convergent methods from psychophysics, neuroimaging, and noninvasive brain-stimulation with normal and tone-deaf (TD) subjects were employed to show that neural networks controlling pitch perception and production systems include bilateral frontotemporal networks. First, psychophysical data showed that the perception and production of pitch are uncorrelated in TD subjects, suggesting a disconnection between perception and production brain regions. This disconnection was extended in a diffusion tensor imaging study in TD and control subjects: tractography revealed that the arcuate fasciculus, which connects temporal and frontal lobes, is reduced in TD subjects, especially in its superior division in the right hemisphere. This disconnection highlights the importance of frontotemporal interactions in music processing. Finally, to reverse-engineer the perception-production network, transcranial direct current stimulation was applied over superior temporal and inferior frontal regions. Results showed diminished accuracy in pitch matching after stimulation compared to sham control. Taken together, results demonstrate that intact function and connectivity of a distributed cortical network, centered around bilateral superior temporal and inferior frontal regions, are required for efficient interactions with sounds in the environment. [Supported by NIDCD.]
Music through hearing aids: Perception and modeling.
Authors: Fitz Kelly , McKinney Martin F.
Published: March 2010

Historically, the primary focus of hearing aid development has been on improving speech perception for those with hearing loss. Modern-day hearing-aid wearers, however, face many different types of acoustic signals, such as music, that require different types of processing. Music signals differ from speech signals in a variety of fundamental ways, and relevant perceptual information is conveyed via different signal attributes in the two types of signals. The research described here is an effort to improve music perception in listeners with hearing impairment. First, methods have been developed to quantitatively measure deficits in music perception for impaired and aided listeners. Second, specific perceptual features have been evaluated as to their relative importance in the successful perception of music and that information has been used to guide signal processing development. Finally, the relevant perceptual features have been modeled, and the models have been used to evaluate and compare signal processing algorithms designed to improve music perception through hearing aids. An overview of our research will be presented along with key recent results.
Neural correlates of sensory consonance and dissonance in primate primary auditory cortex.
Authors: Steinschneider Mitchell , Fishman Yonatan I.
Published: March 2010

The perception of consonance and dissonance of isolated chords (sensory consonance/dissonance) is fundamental to music appreciation. Consonant chords are composed of tones related to each other by simple frequency ratios (e.g., perfect fifth 3:2), whereas dissonant chords are composed of tones related to each other by complex ratios (e.g., minor second 256:243). Dissonance is thought to be due to the perception of beats (modulation frequencies < 20 Hz) or roughness (modulation frequencies from 20–250 Hz), which occur when two or more components of a complex sound are separated from one another in frequency by less than the width of an auditory filter (i.e., critical bandwidth). These unresolved frequency components interact in the auditory periphery to produce amplitude-modulated (AM) fluctuations in the composite waveform envelope. We demonstrate that the magnitude of neuronal phase-locking to these AM fluctuations in primary auditory cortex of awake monkeys correlates with the perceived consonance/dissonance of musical chords and parallels human perception of roughness. This correlation is displayed by population activity, as measured by auditory evoked potentials (AEPs), current source density, and multiunit activity. We further demonstrate that phase-locking of AEPs in Heschl’s gyrus of humans is similar to that seen in the monkey.
Sonar-induced strains and stresses in an absorbing solid elastic sphere.
Authors: Foote Kenneth G. , Francis David T. I. , Zampolli Mario , van Zon Tim
Published: March 2010

The interaction of harmonic plane and spherical pressure waves with an absorbing solid elastic sphere is modeled. The analytic, boundary-element-method (BEM) and finite-element-method (FEM) solutions for the internal displacement, strain, and stress fields are evaluated numerically for 50-mm-diameter solid spheres of poly(methyl methacrylate) (PMMA) and high-density polyethylene (HDPE) in an immersion medium of mass density 1000 kg/m3 and sound speed 1500 m/s. The mass density and longitudinal and transverse sound speeds of the PMMA sphere are 1191 kg/m3, 2690 m/s, and 1340 m/s, respectively. The corresponding properties of the HDPE sphere are 957 kg/m3, 2430 m/s, and 950 m/s. The two materials are assumed to have a hysteresis-type absorption, hence with constant product of absorption coefficient and wavelength. The respective values of this product for longitudinal and shear waves for PMMA are assumed to be 0.19 and 0.29 dB, and for HDPE, 0.40 and 1.20 dB. Each of two frequencies is considered, 10 and 100 kHz, for which the wavenumber-radius product is π/3 and 10π/3, respectively. Results for the three solution methods are compared. [Work partly supported by NOPP through ONR Award No. N000140710992.]
Effective mass density of a random configuration of cylinders.
Authors: Luppé Francine , Conoir Jean-Marc , Pareige Pascal
Published: March 2010

The dynamic effective mass density of a random distribution of n0 cylinders/m2 in an ideal fluid is looked for. The Fikioris and Waterman approach is used to obtain the reflection coefficient of the random half-space at the plane interface with the ideal fluid. This coefficient is expanded into powers of n0, using Linton and Martin’s expansion of the wavenumber of the coherent wave. The reflection coefficient is then compared to that obtained when a homogeneous viscous fluid replaces the random medium. When the two reflection coefficients are equal, the random fluid is acoustically equivalent to the viscous one, which is thus considered as the effective fluid. The coherent wave in the random medium is described as the acoustic mode in the effective fluid, with the shear viscosity of the latter being set to zero. Equating the two reflection coefficients provides an effective mass density that depends on frequency and on the incidence angle, except at low frequency. The angle dependence is discussed.
Perception of vocal imitations and identification of the imitated sounds.
Authors: Lemaitre Guillaume , Dessein Arnaud , Aura Karine , Susini Patrick
Published: March 2010

We report two studies investigating how vocal imitations enable the recognition of the imitated sounds. First, we asked couples of participants to listen to series of everyday sounds. One of the participants (“the speaker”) had then to describe a selected sound to the other one (the “listener”), so that he could “guess” the selected sound. The results showed that, spontaneously, the speakers used, among other para-linguistic cues, large numbers of vocal imitations. Moreover, they suggested that the identification performances were increased when vocal imitations were used, compared to only verbal descriptions. Second, we sampled 28 sounds across an experimental taxonomy of kitchen sounds and required laypersons to vocally imitate these sounds. Another group of participants was then required to categorize these vocal imitations, according to what they thought was imitated. A hierarchical cluster analysis showed that, overall, the categories of vocal imitations fitted well with the categories of imitated sound sources. By using finer analysis techniques, we also showed that some imitations inconsistently clustered. On the other hand, the consistent clusters of imitations were perfectly predicted by a few acoustical descriptors. We therefore conclude that vocal imitations of sounds contain enough information for the recognition of the imitated sounds.
Misperceptions of foreign language phonology.
Authors: Yarmolinskaya Julia , Wilson Colin , Rapp Brenda
Published: March 2010

For many years it has been assumed that when hearing familiar sounds in unfamiliar combinations, listeners will perceive the sounds accurately. In the recent years, this assumption has been challenged [Halle et al. (1998) and Berent et al. (2006)]. The present study investigates what listeners actually hear when presented with familiar consonants in unfamiliar combinations. A group of monolingual native English speakers was asked to transcribe Russian words containing only consonants attested in English but presented in a two-, three-, and four-consonant combinations (CC, CCC, and CCCC clusters) which are not legal in English. The results indicate that the accuracy of response and the nature of errors depend on the type of cluster. CC clusters (e.g., /pn/) were most often misperceived as containing a vowel between the two consonants, and perception accuracy was well-explained by phonological principles, such as sonority. On the other hand, CCC (e.g., /vzb/) and CCCC (e.g., /fstr/) cluster transcriptions contained relatively few vowel insertions, but many deletions and substitutions and their accuracy were better explained by acoustic factors, such as voicing of the consonants. These results suggest that speech perception is influenced by both phonological and acoustic factors.
Word segmentation of American English /s/ in semi-spontaneous speech.
Authors: Kim Dahee , Szostak Christine , Widmer Colin , Pitt Mark A.
Published: March 2010

To comprehend spoken language, listeners need to find words from a continuous stream of speech sounds. Little work has explored whether there are reliable acoustic cues to word boundaries in conversational speech, which is highly reduced and under-articulated, potentially creating ambiguities at word boundaries. Segmentation may be even more difficult when the same segment repeats at a word boundary, ending the preceding word and beginning the following word (e.g., gas station). Segmentation in this environment was investigated by examining the production and perception of fricative /s/ in semi-spontaneous speech. Twenty talkers produced sentences containing ambiguous two-word sequences with /s/ between the two words. All sequences are interpretable in three ways (e.g., grow snails, gross snails, and gross nails) depending on how the frication is segmented. Acoustic analyses of the production data examined whether there are acoustic cues distinguishing the three versions of the ambiguous sequences. Listening experiments using the talkers’ productions as stimuli evaluated the degree of ambiguity in the tokens and identified acoustic cues that listeners use to segment the two words. Results will be discussed in the context of theories of speech perception and word segmentation.
Perception of prosodic boundaries in spontaneous speech with and without silent pauses.
Authors: Mo Yoonsook , Cole Jennifer
Published: March 2010

In speech comprehension, listeners attend to variation in multiple acoustic parameters encoding prosodic structure. Given the multiplicity of acoustic cues, we ask whether prosody perception is dependent on any individual cue or whether acoustic redundancy encoding prosody supports robust prosody perception in the absence of an individual cue. The present paper reports on a study of boundary perception in spontaneous speech with and without silent pause as a boundary cue. Prior studies show that in read speech, silent pause is important for boundary perception, while in spontaneous speech, listeners can detect boundaries without pauses. Our study tests the role of pause in boundary perception with two versions of 36 short speech excerpts from the Buckeye Corpus: one with pauses intact and another with all pauses truncated to 20 ms. In real-time transcription tasks based only on auditory impression, boundary locations were marked by 74 subjects for the intact stimuli and by an additional 15 subjects for truncated excerpts. Inter-transcriber agreement was comparable across the intact and truncated conditions. Paired-sample t-tests show significantly higher rates of boundary perception for intact stimuli indicating that silent pause is an important but not necessary cue to boundary perception and cue redundancy allows for robust perception.
Dichotic digit listening in Mandarin and English by Mandarin-speaking adults.
Authors: Liu Shu-Yu , Liao Jia-Shiou
Published: March 2010

This study examines Mandarin speakers’ performance on Mandarin and English dichotic digit recognition tests (DDTs). The 60 right-handed subjects, whose primary language was Taiwan Mandarin, had started English as their second language no later than in seventh grade and continued with English through their freshman year in Taiwan. All the subjects were tested on their ability to pronounce and use English digits before participating in the experiments. Subjects took Mandarin one- and two-pair DDTs, and English one- and two-pair DDTs, in free-recall paradigms. In each DDT, subjects were asked to report the digits orally in any order no matter in what order they had heard the numbers in each ear. The scores were calculated from the number of digits the participants responded correctly to in each ear on one- or two-pair tests; they were then statistically analyzed. The English one- and two-pair recognition tests showed a significant right-ear advantage (REA) but not the Mandarin ones. The scores on the Mandarin one- or two-pair DDTs are higher than those on the English ones, suggesting REA or the influence of the non-native language on the subjects’ performance.
Perceptual similarity of unfamiliar regional dialects.
Authors: Tamati Terrin N.
Published: March 2010

Linguistic experience has been shown to influence the perception of regional dialect variation. Recent studies have found that the amount and type of experience with regional dialect variation affect performance in identifying or categorizing regional dialects. Experience also shapes the perceived similarity among regional varieties. To examine the effect of familiarity on the perceived similarity of regional dialects, a paired comparison perceptual similarity rating task was carried out with a group of unfamiliar regional dialects. Native speakers of American English made explicit judgments about the similarity of unfamiliar talkers from the United Kingdom and Ireland based on the regional dialect. Results show that listeners judged the regional dialects of pairs of talkers from the same dialect region as more similar than those of pairs of talkers from different dialect regions. A multidimensional scaling analysis revealed two dimensions of perceptual dialect similarity, both reflecting the geographic location of the cities of origins of the talkers (north versus south and east versus west). Thus, despite being unfamiliar with the regional dialects in the study, listeners were able to use dialect-specific differences in the acoustic signal to make judgments on the perceptual similarity of talkers based on regional dialect.
Identification of the place of articulation of trilingual postvocalic nasals and stops by native speakers of American English, Korean and Japanese.
Authors: Nozawa Takeshi , Cheon Sang Yee
Published: March 2010

Native speakers of American English and Korean produced postvocalic nasals and stops in /CVC/ frames in which the syllable final segment was a consonant with airstream blocking, and native speakers of Japanese produced more nasal /N/ and obstruent /Q/ in /CVNCV/ and /CVQCV/ frames. In Japanese stimuli, the consonant after the nasal or the obstruent was always a stop. Their utterances were recorded and edited to be used as stimuli for the experiment. The release burst of the English stimuli and the second syllable of Japanese stimuli were deleted. Native speakers of these three languages were recruited as listeners. They identified the place of articulation of the syllable-final nasals and stops of the three languages. As predicted, Japanese listeners performed most poorly because there are no phonemic contrasts between postvocalic nasals or stops in Japanese. Korean listeners outperformed the other two groups of listeners in identifying the place of articulation. Postvocalic stops in Korean are not released, so the Korean listeners may not depend on the release burst to identify the place of articulation of a syllable final stop. However, they made more voicing errors than American listeners probably because voiced stops in Korean cannot occur in a postvocalic position.
Cross-linguistic perception of velar and alveolar obstruents: A perceptual and psychoacoustic study.
Authors: Arbisi-Kelm Timothy , Edwards Jan , Munson Benjamin
Published: March 2010

It is well-known that velar stop consonants coarticulate more with the following vowel than stops at other places of articulation. The fine phonetic detail of this coarticulation is highly language-specific. For example, /k/ in Greek is more front before front vowels and more back before back vowels relative to /k/ in English [Arbisi-Kelm et al. (2008)]. The purpose of this study was to investigate how these cross-linguistic differences in production influence perception of place of articulation for lingual stops. The stimuli were word-initial consonant-vowel (CV) sequences excised from words produced by 2- to 5-year-old children and adults. The listeners were 20 adult native English speakers (tested in Minneapolis, USA) and Greek speakers (tested in Thessaloniki, Greece) who listened to these sequences combined across ages and languages in a visual analog scaling task [Urberg-Carlson et al. (2008)]. Listeners rated how alveolar or velar each sequence was by clicking on a double-headed arrow anchored with language-specific orthographic representations of the target consonants. Results showed that the two groups of adults perceived the sounds differently, as would be expected. We will report on the relationship between listeners’ perception and psychoacoustic properties of the stop bursts. [Work supported by NIDCD 02932 and NSF BCS072914 and BCS0729277.]
Perceptual learning of talker-idiosyncratic phonetic cues.
Authors: Jesse Alexandra , Newman Rochelle S.
Published: March 2010

A number of recent studies have explored “perceptual learning,” in which listeners use lexical knowledge to learn about a talker’s idiosyncratic phoneme pronunciations and adjust their perception of other tokens from that talker accordingly. In a typical perceptual learning study, listeners might hear an item that is ambiguous between “crocotile” and “crocodile” during exposure. Since only crocodile is a word, listeners would learn (following several examples) that this talker has long VOTs, and subsequently at test show a shift in their categorization of a /d/-/t/ VOT continuum by the same talker. The present study explored perceptual learning through cues rather than through lexical knowledge. We used a phonetic contrast (s-th) in which there are both primary (spectral) and secondary (amplitude/duration) cues to phonetic identity. Listeners heard tokens of minimal s-th word pairs in which either the primary or secondary cue was ambiguous, but the alternative cue was unambiguous and thus disambiguated the phonetic identity of the word. We tested whether listeners use the unambiguous cue to learn about the speaker’s production of the ambiguous cue (even though doing so was unnecessary for lexical identification) which would then influence later perceptual identification of a series based only on that cue.
Talker-specific accent: Can speech alignment reveal idiolectic influences during the perception of accented speech?
Authors: Miller Rachel M. , Sanchez Kauyumari , Rosenblum Lawrence D. , Dias James W. , Dykmans Neal
Published: March 2010

Listeners use talker-specific (idiolectic) information to help them perceive and remember speech [e.g., Goldinger, J. Exp. Psychol. Learn. 22, 1166–1183 (1998)]. However, recent research has shown that idiolectic information is not as helpful when listeners hear accented speech [e.g., Sidaras et al., J. Acoust. Soc. Am. 125, 5 (2009)]. It could be that listeners fail to encode idiolectic information when perceiving accented speech. To examine whether idiolectic is still encoded, experiments tested if subjects would display speech alignment to specific accented models. Speech alignment is the tendency to imitate another talker and can occur when shadowing heard speech [e.g., Goldinger, Psychol. Rev. 105, 251 (1998)]. Native English subjects were asked to shadow a Chinese- or Spanish-accented model producing English words. Raters then judged whether the shadowed tokens were more similar in pronunciation to those of a shadowed model or of a different models with the same accent. In a second experiment, raters judged whether shadowed tokens were more similar in accent to those of (unshadowed) models with the same or a different accent. Preliminary results reveal that subjects align to the shadowed model, suggesting that idiolect is still encoded. Subjects also show moderate alignment to accent.
PRESTO: Perceptually robust English sentence test: Open-set—Design, philosophy, and preliminary findings.
Authors: Park Hanyong , Felty Robert , Lormore Kelly , Pisoni David B.
Published: March 2010

Traditional clinical word recognition tests (e.g., SPIN and HINT) do not reflect variability in real world environments. These tests are often constructed with predictable short sentences spoken by a small number of talkers without dialect variation; thus, individual differences are difficult to uncover. To compensate for these shortcomings, PRESTO uses materials taken from the TIMIT database in order to incorporate variation in talkers, dialects, and number of words in a sentence. Familiarity and lexical frequency, syntactic structure, and semantic content are also considered. To provide normative data, normal-hearing young listeners performed an open-set identification task with the PRESTO materials in open field with six-talker babble mixed at different signal-to-noise ratios and also with no additional background noise. The HINT sentences were also used with the same listeners to assess the validity of PRESTO. Results indicate that listeners perform near ceiling for both the PRESTO and HINT materials in ideal listening conditions. However, under degraded listening conditions, the PRESTO shows much greater variability. Preliminary results from a clinical population also indicate that the more challenging PRESTO lists reveal individual differences among patients which are not apparent from scores on the HINT. [NIDCD T32-DC00012.]
Defining uncertainty with maximum entropy method.
Authors: Knobles David P. , Sagers Jason , Koch Robert
Published: March 2010

The maximum entropy (ME) method was strongly defended and advocated by E. T. Jaynes as a means to define uncertainty. Here, the ME method is applied to the estimation of ocean waveguide parameter probability distributions from measured acoustic data. An ME analysis produces a canonical distribution, well known from equilibrium statistical mechanics, which is the distribution that maximizes the entropy subject to constraints that reflect selected features of the measured data and a model. The ME method gives the most conservative distribution based only on the measured data and observed features. A Bayesian approach also has the goal of defining uncertainty, but starts from the specification of the likelihood function and the model priors. Data noise is naturally handled in the specification of the likelihood function. The discussion introduces simple examples, showing basic relationships between the constraints in ME and the maximum likelihood estimation. In special cases the form of the likelihood function used in Bayesian conditionalization can be derived from the ME approach. The form of the cost function is an important consideration in comparing ME and Bayesian methods of inferences. In general ME and Bayesian inferences lead to different results. [Work supported by ONR Code 321 OA.]
Automatic signal detection in noise using entropy.
Authors: Erbe Christine
Published: March 2010

Automatic detection of signals in noise is a common problem in many areas of acoustics. In the field of passive acoustic monitoring of marine mammals, the signals to be detected are vocalizations. The noise originates from natural (wind, waves, and rain) and man-made sources (e.g., shipping, construction, and seismic surveys). Signal characteristics vary broadly: frequency ranges from a few Hz to 200 kHz, duration from milliseconds to seconds to hours. Noise characteristics vary by similar orders of magnitude. While specific automatic detectors have been designed to successfully find specific calls in specific environments, the challenge is to find a large variety of calls in a large variety of noise. An exploitable difference between calls and noise is that most noise is a result of stochastic processes (wind, waves, rain, cavitating propellers + seismics generate gas bubbles underwater of varying size + resonance frequency), while many animal signals are a result of deterministic processes (vibrating strings & cavities of predetermined/fixed size). Shannon entropy was computed for power spectrum density functions of underwater recordings. Noise yielded high signal low entropy. Results are presented from passive acoustic surveys of marine mammals. The benefits and limitations of entropy applied to automatic signal detection are discussed.
The likelihood ratio and Bayesian signal processing.
Authors: Culver R. Lee , Jemmott Colin W.
Published: March 2010

Over the past several years, we have been developing an architecture for classifying source depth associated with passive sonar signals. The classifiers utilize the statistics of a signal parameter which are estimated using knowledge of the environment and an acoustic propagation program. We have applied the likelihood ratio (LR) test to classify source depth using signal statistics from the SWellEx-96 and 1996 Strait of Gibraltar sea tests. More recently Bissinger developed a Hellinger distance classifier, and Jemmott is developing a histogram (discrete Bayesian) filter for this purpose. In this talk, we examine the relationship between the LR test and a processor that makes use of Bayes rule. We consider some of the fundamentals. It is useful to understand the underlying assumptions of the LR, the likelihood function, and how they are related to a Bayesian processor which makes use of prior information and computes a posterior probability distribution function. Under what conditions do the two processors produce the same answer? When would the Bayesian processor be a better choice? We compare the processors and apply them to the SWellEx-96 data. [Work supported by the Office of Naval Research Undersea Signal Processing.]
Using Bayesian inference for acoustic array design.
Authors: Goggans Paul M. , Chan Chung-Yong
Published: March 2010

Because inference and design are both generalized inverse problems, the tool and methods developed for Bayesian parameter estimation and model comparison can be adapted and used for the solution of design problems. As an example, this paper presents the use of the Bayesian inference framework for the automated design of linear transducer arrays [P. M. Goggans and C.-Y. Chan, “Antenna array design as inference,” AIP Conf. Proc. 1073, 294–300 (2008)]. Commonly, automated array design is cast as an optimization problem and solved using numerical optimization techniques. Here, the design of linear arrays is cast as an inference problem and solved using numerical Bayesian inference techniques. Compared to optimization-based methods, the inference-based method presented here has the advantage of being able to automatically determine the number of array elements required to satisfy design requirements and specifications. In addition, array design cast as inference can incorporate, as prior information, design requirements such as a minimum spacing between two adjacent elements, a maximum aperture width, and a necessary operating frequency bandwidth. Sample results are presented to demonstrate the application of the Bayesian inference framework in the automated design of linear arrays.
Particle filtering for sequential multipath arrival time and amplitude estimation.
Authors: Jain Rashi , Michalopoulou Zoi-Heleni
Published: March 2010

Accurately estimating arrival times from acoustic time series in the ocean is essential for successful source and array element localization and estimation of the geometry of the sound propagation environment and environmental parameters such as sound speed in the water column and sediments. We have developed a sequential Monte Carlo method that characterizes multipath arrivals as moving targets, tracking them at spatially separated receiving phones. We focus on switching models that are suitable for unknown and varying numbers of arrivals at different phones. We also present approaches that efficiently and effectively extract amplitude information from received time series; such information can be then employed for sediment characterization. Our methods are applied to Haro Strait Primer and Shallow Water 06 data; their performance is evaluated through comparisons to conventional approaches. [Work supported by ONR.]
Three-dimensional source tracking in an uncertain environment via Bayesian marginalization.
Authors: Tollefsen Dag , Dosso Stan E.
Published: March 2010

This paper develops a non-linear Bayesian marginalization approach for three-dimensional source tracking in shallow water with uncertain environmental properties, with application to horizontal line array (HLA) data. The algorithm integrates the posterior probability density via a combination of Metropolis–Hastings sampling over environmental and bearing model parameters and Gibbs sampling over source range and depth, with a priori track constraints on source velocity. Two-dimensional marginal distributions for source range/depth and range/bearing are derived. The Viterbi algorithm is applied to obtain the most probable track, with uncertainties estimated from the marginal distributions. The algorithm is applied to simulated data in continental shelf environment and to towed-source and ship-noise data recorded on a HLA deployed on the seafloor in an experiment conducted in the Barents Sea.
Improving the parabolic equation solution for problems involving poro-elastic media.
Authors: Metzler Adam M. , Siegmann William L. , Collins Michael D. , Baer Ralph N. , Collis Jon M.
Published: March 2010

Parabolic equation solutions for elastic media have undergone several modifications recently that increase their capabilities and accuracy. These include formulation in different dependent variables, approaches for handling range dependence such as coordinate rotations and single scattering, and treatment of media anisotropy. These advances are being extended to problems with heterogeneous and range-dependent poro-elastic media, which provide useful models of some shallow-water sediments. Other parabolic equation solutions for poro-elastic media [Collins et al., J. Acoust. Soc. Am. 98, 1645–1656 (1995)] are prior to recent progress. Vertical dependence is treated by applying heterogeneous depth operators from the equation of motion. Horizontal dependence is treated by incorporating single-scattering approaches. [Work supported by the ONR.]
Improving the parabolic equation solution for problems involving sloping fluid-solid interfaces.
Authors: Collins Michael D. , Siegmann William L.
Published: March 2010

Several approaches are being investigated for improving the elastic parabolic equation for problems involving sloping fluid-solid interfaces. Approaches based on single scattering and energy conservation provide accurate solutions for problems involving sloping fluid-fluid and solid-solid interfaces, but the mixed-media problem has proven to be more challenging. The energy-conservation approach has been applied previously by deriving a linear equivalent to the nonlinear expression for energy flux. One of the approaches that are currently being investigated is based on going back to the nonlinear expression. Although it would not be practical to solve the full nonlinear scattering problem, promising results have been obtained for the fluid-fluid case with this approach by correcting the amplitude at only one grid point near the interface. With this approach, the nonlinear problem reduces to the evaluation of a quadratic function. Another approach that is being investigated is based on an alternative formulation that involves the vertical displacement and a quantity that is proportional to the normal stress on a horizontal interface. In these variables, the interface conditions across a horizontal interface are first order, and this may facilitate the extension of the single-scattering solution to the mixed-media problem. [Work supported by the Office of Naval Research.]