bluuebunny/crossref_metadata_2025 huggingface dataset:
Normalized recognition of speech and audio events
Authors: Hasegawa-Johnson Mark A. , Huang Jui-Ting , King Sarah , Zhou Xi
Published: October 2011

An invariant feature is a nonlinear projection whose output shows less intra-class variability than its input. In machine learning, invariant features may be given a priori, on the basis of scientific knowledge, or they may be learned using feature selection algorithms. In the task of acoustic feature extraction for automatic speech recognition, for example, a candidate for apriori invariance is provided by the theory of phonological distinctive features, which specifies that any given distinctive feature should correspond to a fixed acoustic correlate (a fixed classification boundary between positive and negative examples), regardless of context. A learned invariance might, instead, project each phoneme into a high-dimensional Gaussian mixture supervector space, and in the high-dimensional space, learn an inter-phoneme distance metric that minimizes the distances among examples of any given phoneme. Results are available for both tasks, but it is not easy to compare them: learned invariance outperforms a priori invariance for some task definitions, and underperforms for other task definitions. As future work, we propose that the a priori invariance might be used to regularize a learned invariance projection.
An automatic method for determining phonetic boundary for continuous speech utterances in an open source multi-language audio/video database
Authors: Karnjanadecha Montri , Zahorian Stephen A.
Published: October 2011

Nine hundred video clips (approximately 30 h in each of English, Mandarin, and Russian) have been collected from Internet sources such as youtube.com and rutube.ru. This multi-language audio/video database has been orthographically transcribed by human listeners with time markers at the sentence level. However, the aim is to provide this database to the public with high accuracy time markers at the phonetic level, which will greatly increase the value of the database. This paper describes an approach to achieving high accuracy automatic phonetic labeling based on a Hidden Markov Model speech recognizer. This automatic method was developed due to the great length of time and tediousness of performing this task using only human listeners. One major challenge for the automatic method was that the audio data consists of spontaneous speech with unconstrained topics and the speech was spoken under various acoustic conditions. The approach begins with a well-trained acoustic model for each language. The acoustic model is then adapted to each passage and finally the phonetic labeling of the passage is determined. Comparison of the automatically determined phone time markers with those obtained by human listeners, for a subset of the speech materials, shows the accuracy of the automatic method.
Acoustic evidence for protracted development of monosyllabic Mandarin tone production by Taiwanese children
Authors: Yu Xin , Yang Jing , Wong Puisan
Published: October 2011

The current study examines the acoustic characteristics of monosyllabic Mandarin tones produced by 3-y-old children growing up in Taiwan. Four hundred monosyllabic tone productions were collected from 11 adults and 10 children and were judged by 5 Mandarin-speaking adults to determine tone accuracy. Seven acoustic parameters strongly associated with Mandarin tone perception were measured in these productions and compared among children's and adults correct and incorrect productions. The findings indicate that children do not produce the high level tone with fundamental frequencies (f0) as high or level as adults. Children's rising, falling, and dipping tones do not reach f0 ranges as low as adults. These results are largely consistent with the findings in our previous acoustic study on the monosyllabic Mandarin tones produced by 3-y-old children growing up in the U.S. Taken together, 3-y-old Mandarin-speaking children growing up in the U.S. and Taiwan do not produce adult-like monosyllabic Mandarin tones. Even children's productions in which the tonal targets are correctly perceived by adults are acoustically different than the adult forms. Children demonstrate more difficulties producing low f0 targets. The findings provide acoustic evidence to support a much more protracted process for Mandarin lexical tone acquisition than most studies have suggested.
A three-dimension propagation model using stepwise coupled modes
Authors: Ballard Megan S.
Published: October 2011

A propagation model has been developed that is applicable to shallow-water waveguides characterized by three-dimensional inhomogeneities which induce horizontal refraction and mode coupling. A normal-mode approach is chosen for this work because the field decomposition into modal amplitudes provides insight into the effects of the environment on the acoustic field. The model is based on the stepwise coupled-mode technique implemented with the single-scatter approximation [R. B. Evans, J. Acoust. Soc. Am. 74, 188–195 (1983)]. The stepwise technique discretizes a range-dependent environment into a series of range-independent segments. The single-scatter solution is obtained by treating each pair of segments as an independent problem, thus neglecting the higher-order terms resulting from multiple scattering at other interfaces. The field is propagated using the parabolic equation in cylindrical coordinates. Thus, at each range step, horizontal refraction is accounted for in the angular direction and mode coupling is included in the radial direction. Examples illustrating the effects of horizontal refraction and mode coupling will be presented. [Work supported by ONR.]
Equation, describing temporal evolution of the sound pulse in horizontal plane in shallow water
Authors: Katsnelson Boris
Published: October 2011

It is shown that for comparatively narrow-band pulses in shallow water sound propagation, it is possible to introduce modal pulses, corresponding to variation (or evolution) of space-time dependence of the amplitude of separate waveguide modes. In ray approximation, in the presence of perturbation depending on horizontal coordinates, these signals propagate along different trajectories in horizontal plane (space-time horizontal rays) depending on mode number and frequency. In the paper equation, describing evolution of amplitude of modal pulses as a function of time in horizontal plane outside the ray approximation is obtained. This equation can be considered as extension of well-known parabolic equation in horizontal plane. Examples of solutions for some shallow water models are shown; applicability of this equation is discussed.
Robust computation of acoustic normal modes in attenuating ocean waveguides
Authors: Hayward Thomas J. , Oba Roger M.
Published: October 2011

The normal mode representation [Jensen etal., Computational Ocean Acoustics, AIP Press, 1997] provides for the mathematical analysis and numerical computation of acoustic fields in a range-independent ocean waveguide. Existing algorithms [e.g., M. B. Porter and E. L. Reiss, J. Acoust. Soc. Am. 77, 1760] provide for efficient computation of the mode eigenvalues and eigenfunctions for narrow-band acoustic fields. However, for extensive computations involving a large set of environmental parameter values or acoustic frequencies, reliability issues, such as eigenvalues omitted in the calculation, have been noted in the case of attenuating media. In this work, a computational method is presented that computes the normal modes by approximate solution of the mode depth-dependence equation on a discrete computational grid, using a selected discrete basis. Empirical evidence of the robustness of the method is provided by comparisons with established numerical benchmarks and by examining the acoustic parameter dependence of the mode spectra over thousands of parameter values. Theoretical support for the reliability of the computation is then discussed. [Work supported by the Office of Naval Research.]
An investigation of the effects of rough seas and bubble injections on high frequency propagation using a parabolic equation method
Authors: Senne Joseph M. , Song Aijun , Smith Kevin , Badiey Mohsen
Published: October 2011

High frequency underwater acoustic transmissions (>10 kHz) are heavily influenced by scattering from both rough surfaces and bubbles. These interactions are recorded through the prevalence of micro multi-paths in observed data. To study these scattering effects, a rough-surface variant of the Monterey Miami parabolic equation model was combined with a hydrodynamic surface model that produces non-linear waves along with depth- and range-dependent bubble distributions. Parabolic equation setup parameters were taken from collected environmental data, while a wave-rider buoy was used for time-evolving sea surface generation. Bubble plume densities were calculated using surface white-cap distributions along with a bubble evolution scheme. Comparisons of the simulated results are made against collected acoustic data for calm and rough sea states [Work supported by ONR Code 322OA.]
Soundscape ecology: A worldwide network
Authors: Guastavino Catherine , Pijanowski Bryan C.
Published: October 2011

The overarching objective of our network is to bring together acousticians, cognitive psychologists, ecologists, and creative artists to integrate how they study and perceive soundscapes and use this knowledge to help shape a research agenda for the conservation of soundscapes. Many natural soundscapes are being threatened from various directions, e.g., habitat destruction, climate change, invasive species. This project aims at recording and documenting soundscapes in remote locations and identifying conceptualizations of these soundscapes across different cultures and disciplines. The network will help to (1) foster open communication between different disciplines and communities about soundscapes; (2) coordinate soundscape monitoring sites where acoustic data are being collected long-term; (3) develop a common vocabulary, long-term monitoring standards, and metadata standards for acoustic data for use by ecologists; (4) increase awareness of this new field among ecologists and social scientists; and (5) increase public awareness of the importance of their acoustic connection to nature. This project on the soundscapes of natural ecosystems is a logical complement to research underway at the European level on urban soundscapes (COST action TD0804). Together, this worldwide network of researchers will be uniquely situated to contribute decisively to a cross-cultural conservation framework for soundscapes.
The introduction of the concept of soundscape to urban design analysis
Authors: Tomalova Maria
Published: October 2011

The objective of this paper was to provide pragmatic approach through the analysis of Covent Garden Piazza's soundscape with intention to show the way of its implementation into urban design analysis, whereas analysis of soundscape is missing part of urban design analysis. So, soundscape suppose to be a new tool for designer to create more pleasant sound ambient environments not only for users who are able to perceive urban space visually but also for those who can use another senses only like aural and tactile to identify relevant quality of urban places. In this research were employed methods of subjective evaluation and spatial analysis of soundscape (entirely qualitative research). The data were collected through exploration of the soundscape preference and level of awareness of ambient sound environment within explorative single case study and thorough observation of activities on the study site and investigation of urban form. Thus, the urban uses and activities of the location and its acoustic identification are closely linked. Recent urban analyses generally take only human and technical noises into consideration, excluding the rest of noises of sonic environment and way of their perception by human beings. Acoustic dimensions must be available for design.
The care and feeding of clients with variable room acoustics systems
Authors: Logsdon Edward
Published: October 2011

The care and feeding of clients with variable room acoustics systems. Now that the Variable Room Acoustics System (VRAS) is designed and installed in the room, what do you do? An Acoustical Consultant's Perspective One of the primary educational goals for the Colorado College, Edith Kinney Gaylord Cornerstone Arts Center in Colorado Springs, CO, is to encourage collaboration between the music, drama, dance, film, and visual artists who perform and display their work in the facility. The building offers many opportunities for film/video and theater students, or music and sculptural artists to work together on multimedia presentations. We used “collaboration” to further encourage the student and faculty performers and artists to communicate their needs and priorities for use of the multipurpose main theatre early on in the design. Subjective opinions of how the room sounds, or how best to control the VRAS system, had to be carefully addressed and assessed to avoid confusion and to achieve unanimity. We will review our process of establishing an artistic vocabulary that allowed a jury of users to advise us on the types and number of room presets needed for the various uses of the theatre and the validation and approval of the system.
Acoustical design of New World Center, Miami Beach, FL
Authors: Beckmann Daniel F. , Kallas Kayo , Komoda Motoo , Toyota Yasuhisa
Published: October 2011

The New World Center opened in January 2011 after an 8-year process to design and build the $160 million facility. The Frank Gehry-designed facility for the New World Symphony, “America's Orchestral Academy,” has at its heart the 756-seat auditorium, designed in the arena style. Also in the facility are one large orchestral rehearsal room, seven medium-sized Chamber/Ensemble rehearsal rooms, and 24 individual coaching/practice rooms. Administrative offices and production spaces complement the spaces for music to bring the building to 100 641 square feet. The acoustical design of the 756-seat auditorium was performed in close collaboration with Gehry and the founder of the New World Symphony, acclaimed conductor Michael Tilson Thomas. To ensure validity of the acoustical design, a 1:24 scale model test was performed. Flexibility in rehearsal and performance was one of the prime requirements for the space as the program includes much more than just orchestral performance, which is met by a curtain system for variable acoustics, a highly flexible stage lift system, 247 retractable seats, and four alternate “Performance Platforms.” Five large “sails,” which double as projection surfaces, a proper ceiling above the stage, and a steeply raked audience area are amongst the acoustical design elements that are reported.
Acoustic monitoring of dolphin populations in the Gulf of Mexico
Authors: Frasier Kaitlin E. , Soldevilla Melissa S. , McDonald Mark A. , Merkens Karlina P. , Wiggins Sean M. , Hildebrand John A. , Roch Marie A.
Published: October 2011

High-Frequency Acoustic Recording Packages (HARPs) continuously monitored delphinids at five sites in the northeastern Gulf of Mexico during and after the Deepwater Horizon oil spill. Surface oil reached two sites, while the three unexposed sites functioned as “controls.” Presence of dolphin vocalizations (clicks, whistles, and burst pulses) was documented at exposed and unexposed sites over the course of a year following the oil spill. These sites are within the known habitat ranges of 11 species of delphinids. Broadband towed array recordings with visual identifications were used to determine species-specific vocalization characteristics, which were then compared with autonomously recorded vocalizations. Two species have distinctive vocalizations that match between towed array and autonomous recordings. At least four more unique vocalization patterns were detected autonomously, which may be species-specific. Both clicks and whistles were explored for identifying features. The data provide a comparative view of delphinid presence relative to the oil spill.
Long-term acoustic monitoring of marine mammal response to the 2010 oil spill in the Northern Gulf of Mexico
Authors: Sidorovskaia Natalia , Ackleh Azmy S. , Ma Baoling , Tiemann Christopher , Ioup George E. , Ioup Juliette W.
Published: October 2011

The 2010 deep water horizon (DWH) oil spill in the Northern Gulf of Mexico brought a need for assessing spill impact and recovery timeline for the deepwater ecosystem, including marine mammals. Passive acoustics is emerging as a viable technology to monitor short-term and long-term abundance dynamics and to assess different factors that may cause an observed response. Multi-year pre-spill and post-spill acoustic data collected at different distances from the DWH incident site by the Littoral Acoustic Demonstration Center (LADC) are used to compare first-year oil spill response by three different groups of marine mammals: sperm whales, beaked whales, and dolphins. Densities of acoustic phonations by these animals are extracted from collected data and used for point estimates of the resident population density. As an example, a regional abundance estimate shows a decrease in the number of sperm whales at the site nearest to the DWH (9 mi away) which exceeds statistical uncertainties and can be accepted as an existing trend. The use of acoustic data to extract information about environmental factors, such as anthropogenic noise level or food call densities, that may contribute to the explanation of existing trends is also discussed. [Work is partially supported by NSF.]
Synergistic interaction between stress waves and cavitation is important for successful comminution of residual stone fragments in shock wave lithotripsy
Authors: Lautz Jaclyn , Sankin Georgy , Zhong Pei
Published: October 2011

To assess the role of stress waves and cavitation in comminuting residual fragments during shock wave lithotripsy (SWL), cylindrical 4 × 4 mm BegoStone phantoms were treated in an electromagnetic lithotripter either at the focus (z = 0, p+ = ∼45 MPa) or pre-focally (z = −30 mm, p+ = ∼24 MPa). The treatment was performed with the stone immersed either in degassed water or in Butanediol, which has similar acoustic impedance to water but much higher viscosity to suppress cavitation. At the focus, the first fracture was observed after 26 ± 9 shocks, both in water and Butanediol (p = 0.7). However, when stones were moved pre-focally where comparable cavitation is produced (based on high speed imaging), the average shock number required for the initial fracture was increased to 66 ± 10 in water and 122 ± 20 in Butanediol (p = 0.002). Below −40 mm prefocally (p+ < 20 MPa), stones did not fracture in water even after 2,000 shocks, although cavitation was observed. Furthermore, stone comminution at the focus after 250 shocks was ∼35% in water compared to ∼5% in Butanediol (p < 0.001). Altogether, these findings suggest that a synergistic interaction between stress waves and cavitation is critical in producing effective stone comminution during SWL. [Work supported by NIH and NSF GRFP.]
Acoustical assessment of body water balance
Authors: Sarvazyan Armen
Published: October 2011

A new medical application of acoustics has recently emerged: assessment of body hydration status by ultrasonic measurement of muscle water content. The need for an easy-to-perform method for the detection of water imbalance is of the utmost clinical importance. Body hypohydration may cause severe health and performance problems, decreasing cognitive and physical work capabilities, while excessive hydration is a common symptom of many other diseases. The speed of longitudinal acoustic waves in muscle, as well as in other soft tissues, is defined by tissue molecular composition because both the density and bulk compressibility of tissue depend mainly on short range molecular interactions. Skeletal muscle is the largest water compartment in the body; it comprises 40% of body mass and 75% of muscle is water. The ultrasound velocity in muscle is a linear function of water content with the slope of about 3.0 m/s per 1% change in water content. We will describe the design, measurement principles, and testing results for new acoustic devices for assessment of hydration status of elderly and infants, two most vulnerable groups of population. Advantages and disadvantages of acoustical method of hydration over currently available methods are discussed.
Acoustic intensity vector probes
Authors: Elko Gary W.
Published: October 2011

Modern acoustic intensity measurement techniques began in the early 1980's with the realization that the imaginary part of the cross-spectral density was directly related to the active intensity component along the axis between two closely-spaced pressure microphones. Since acoustic intensity is a vector quantity, it was obvious that one would like to measure all three orthogonal components and to graphically represent acoustic power flow through space. Needing an interesting topic for a Ph.D. thesis at Penn State (and a way of funding it ..., thank-you US Navy), the task of investigating and developing the estimation of the acoustic intensity vector field fortunately came my way. This talk will present some of the early interesting and fun things that came out of working on in-air acoustic vector sensors. It will conclude with some more recent developments that have direct connections to the early acoustic vector probes that were built, tested, and used at Penn State.
Estimation of sea floor properties using acoustic vector sensors
Authors: Crocker Steven E. , Miller James H. , Osler John C. , Potty Gopu R. , Hines Paul C.
Published: October 2011

Information in the acoustic vector field can be used to estimate properties of the environment with which the field interacts. A study was performed to understand the value of vector field data when inverting for sea floor geoacoustic properties. The study compared results obtained with new inverse methods based on measurements of complex acoustic transfer functions and specific acoustic impedance. Acoustic field data consisted of gated continuous wave transmissions acquired with four acoustic vector sensors that spanned the water-sediment interface during the Sediment Acoustics Experiment 2004 (SAX04). Motion data provided by the buried vector sensors were affected by a suspension response that was sensitive to the sediment density and shear wave speed. The suspension response for the buried vector sensors included a resonance within the analysis band of 0.6–2.4 kHz. The response was sufficiently sensitive to the local geoacoustic properties, that it was exploited by the inverse methods developed for this study. Inversions of real and synthetic data sets indicated that information about sediment shear wave speed was carried by the suspension response of the buried sensors, as opposed to being contained inherently within the acoustic vector field. [Work supported by ONR.]
Comparing vector- and pressure-sensor arrays: The 2009 cooperative array performance experiment
Authors: Rouseff Daniel , Light Russell , Wang Zhongkang , Zhou Shihong
Published: October 2011

The 2009 cooperative array performance experiment (CAPE'09) was designed to compare performance between vector- and pressure-sensor arrays. The experiment was a joint effort of Chinese and American investigators; both arrays were designed and assembled by the Hangzhou Applied Acoustics Research Institute (HAARI), while the source systems and signal processing/recording systems were designed and assembled by Applied Physics Laboratory, University of Washington (APL-UW). The two arrays, both approximately 7 m in length, were deployed vertically off the stern of the APL-UW's R/V Robertson in Lake Washington, Seattle. Various transmitted signals in the 1.5–4 kHz band were recorded simultaneously on the two arrays at ranges between 10 m and 4 km. The signals included repeated linear frequency-modulated chirps and communications sequences. The pressure- and vector-sensor arrays had 32 and 8 uniformly spaced elements, respectively. Because each element in the vector-sensor array recorded both pressure and the three components of particle velocity, the two arrays made the same number of measurements over a similar vertical aperture. In the present talk, the design features of the vector-sensor array are emphasized. Sample results for both arrays are presented. [Work supported by ONR.]
Ares I Scale Model Acoustic Tests Instrumentation for Acoustic and Pressure Measurements
Authors: Vargas Magda B. , Counter Douglas D.
Published: October 2011

The Ares I Scale Model Acoustic Test (ASMAT) was a development test performed at the Marshall Space Flight Center (MSFC) East Test Area (ETA) Test Stand 116. The test article included a 5% scale Ares I vehicle model and tower mounted on the Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments located throughout the test article. There were four primary ASMAT instrument suites: ignition overpressure (IOP), lift-off acoustics (LOA), ground acoustics (GA), and spatial correlation (SC). Each instrumentation suite incorporated different sensor models which were selected based upon measurement requirements. These requirements included the type of measurement, exposure to the environment, instrumentation check-outs and data acquisition. The sensors were attached to the test article using different mounts and brackets dependent upon the location of the sensor. This presentation addresses the observed effect of the sensors and mounts on the acoustic and pressure measurements.
Effects of silent interval on human frequency-following responses to voice pitch
Authors: Jeng Fuh-Cherng , Warrington Ronny P.
Published: October 2011

Human frequency-following responses (FFRs) to voice pitch have provided valuable information on how the human brain processes speech information. Recordings of the FFR to voice pitch, however, may overlap when insufficient silent intervals are used. To determine the shortest silent interval that can be used with no overlap between adjacent response waveforms, FFRs were recorded from 12 Chinese adults using a wide range of silent intervals. The stimulus token was a Chinese monosyllable with a rising pitch of 117–166 Hz and a duration of 250 ms. A high stimulus intensity at 70 dB SPL was used to maximize overlaps in the response waveforms. A total of seven silent intervals, ranging from the full length of the stimulus duration down to approximately half period of the fundamental frequency of the stimulus token, were administered at a random order across participants. Two distinct methods (Hilbert transform and root-mean-square amplitudes) were used to delineate the envelopes and overlaps of the response waveforms. A one-way repeated measures analysis of variance was significant (p = 0.038) in defining the magnitude of overlaps for the 10 ms pre-stimulus interval. The results indicated the shortest silent interval that could be used without compromising the response is between 35 and 45 ms.
Psychoacoustics of chalkboard squeaking
Authors: Reuter Christoph , Oehler Michael
Published: October 2011

At least since 1975 the “pleasantness” of a sound is discussed from many different angles (Ely 1975; Aures 1984; Halpern etal. 1986; Vaschillo 2003; Neumann & Waters 2006; Cox 2008), but often chalkboard squeaking or scratching a chalkboard with finger nails tops the list of unpleasant sounds. The aim of the presented study is to detect specific parts of the sounds that make chalkboard squeaking particularly unpleasant. With a combination of perception experiments and electro-physiological measurements, it was analyzed to what extent the knowledge about the sounds influenced the subjects' judgments and/or the physiological reactions. Basically the study is a replication of Halpern etal. (1986), whose methods were extended by several sophisticated sound analysis and re-synthesis techniques and the measurement of some electro-physiological parameters (heart rate and skin resistance) during listening. First results show that especially the modification of the tonal parts as well as applying a filter between 2000 and 4000 Hz led to a more pleasant sound perception. Almost all stimuli were rated more unpleasant if the subjects knew about the nature of the sounds.
Structurized sound design process of electric vehicle interior sound
Authors: Kueppers Thomas , Biermann Jan-Welm , Steffens Jochen
Published: October 2011

The sound character of electric vehicles extremely differs from internal combustion engine vehicles. While the electric vehicle development is still in the beginning, there is potential to consider customer expectations very early in the development process, to have an impact on the typical desired electric vehicle sound on market launch and to generate unique selling propositions in competition between vehicle manufacturers. The current electric powertrain noise is perceived as inconvenient and nonaesthetical especially on long journeys. A complete reduction of this powertrain noise emphasizes the perception of wind and rolling noise and avoids feedback of velocity and load dependency, which decreases emotional impression. Futuristic sounds by sound design systems have to be evaluated by customers and revised in their acceptance and authenticity. Besides the improvement of the sound character, sound design systems can additionally be used to influence the informative acoustic feedback of driving and vehicle parameters. This article introduces the upcoming scenarios for interior sound development and focuses the contradiction between a great amount of freedom in design and a structurized workflow for designing electrical powertrain sounds.
When to punt on speaker comparison?
Authors: Schwartz Reva , Campbell Joseph P. , Shen Wade
Published: October 2011

In forensic speaker comparison, it is crucial to decide when completion of the examination may not possible (punt). We explore the factors that make speaker comparison decisions difficult or impossible. These factors may include duration, noise, speaking style, language/dialect, mental state, number of speakers, type and quality of recording, and deception. The analyst needs criteria to decide to reject case work. We present analysis of some of these factors and their impact on automatic speaker recognition systems. We propose a methodology for setting objective thresholds by which comparison examples can be rejected. This methodology could be used by forensic analysts to decide whether or not to proceed with speaker comparisons involving these factors.
Reduction of consonants and vowels in the course of discourse
Authors: McAuliffe Michael , Babel Molly
Published: October 2011

There is a clear link between the discourse status of a word and the degree of reduction. For instance, Gregory [Dissertation (2002)] provided evidence that hearer knowledge affected reduction in production for discourse-old items. Lexical information, such as word frequency, also plays a crucial role in the degree of reduction [Fosler-Lussier and Morgan, Speech Commun. (1999)]. These previous studies either looked at short discourses or words isolated from context. Therefore, the current study investigates longer discourses, using the VIC Corpus [Pitt etal., Corpus (2007)]. The primary question is to what degree do repeated uses cause further reductions, and if the reductions are syllabically and segmentally uniform across a word. Many studies on reduction rely on the intuition that reductions occur when information load is light, such as when the word was repeated recently or has a high probability of occurrence, so the prediction is that unstressed syllables would show more reduction than stressed syllables, due to their lighter load of information. Likewise, as vowels vary more than consonants across dialects, the informational load of vowel quality may be less than that of consonant quality, so the prediction is that vowels would show greater reductions than consonants.
Automatic analysis of constriction location in singleton and geminate consonant articulation using real-time magnetic resonance imaging
Authors: Hagedorn Christina , Proctor Michael , Goldstein Louis , Narayanan Shrikanth
Published: October 2011

Research on geminate consonants has attempted to establish whether the control of their articulation differs from that of corresponding singletons in temporal parameters, spatial parameters, or both. One piece of evidence supporting spatial control in Italian geminates is EPG results revealing that the location of maximal constriction (CL) of coronal geminates along the palate exhibits small differences from the CL of singletons (Payne 2005). However, our recent work investigating Italian using real-time magnetic resonance imaging (MRI) has shown that when measuring CL dynamically, the CL of singletons and geminates are identical. Dynamic CL is defined as the region of the image that exhibits maximum intensity change during constriction formation and release. These results can be reconciled with the EPG findings if we hypothesize that differences in CL at the moment of maximal constriction are due to compression effects (in the longer geminates) involving the tongue tip sliding along the palate during the closure duration. We evaluate this hypothesis by testing whether CL differences between singletons and geminates can also be found in MRI data, when CL is measured statically (region on the palate contacted in the most constricted frame) in the same utterances in which dynamic CL is invariant. [Work supported by NIH.]
Enhancement of laryngeal features under segmental and prosodic conditioning
Authors: Dutta Indranil
Published: October 2011

Evidence in support of enhancement features (Keyser and Stevens, 2006) is presented from an acoustic study of laryngeal contrasts in Hindi. Segmental contrasts where defining features and their corresponding acoustic outcomes are attenuated are said to be made acoustically salient by enhancing gestural features (Stevens and Keyser, 2010). In this study, the four-way laryngeal contrasts in Hindi are examined under varying prosodic and segmental contexts. In segmental contexts where a defining distinctive feature (slack vocal folds) is attenuated in its acoustic manifestation, namely, closure duration (CD), an enhancing gesture (spread glottis) (Avery and Idsardi, 2001) is added to increase the saliency of contrasts between voiced aspirated stops (VAS) and voiced stops (VS). The acoustic consequence of this enhancement is f0 lowering in the following vowel. Similar results are obtained under weak prosodic conditions where both f0 lowering and increase in spectral tilt result from the enhancing gesture (spread glottis). In addition, in segmental contexts where gestural overlap compromises the feature (slack vocal folds), (spread glottis) by way of f0 lowering in the acoustic dimension enhances the laryngeal contrast between VAS and VS. These results lend support to the theory of enhancement as proposed by Stevens and Keyser (2010).
Recovery of articulatory information from acoustics using linear mixed effects models
Authors: Martin Sean
Published: October 2011

The current study attempts to establish a lower bound on the degree to which articulatory information can be recovered from the speech signal. The recovery of articulatory information is modeled with comparatively simple linear mixed-effects models using synchronized articulatory and acoustic data from the University of Wisconsin X-Ray Microbeam Speech Production Database (Westbury, 1994). The performance of this model is compared with other speech inversion models. While previous work [Mitra etal. (2010) and others] demonstrates that a more sophisticated model can perform speech inversion quite accurately, the results here show that even a strongly constrained linear model performs better than might be expected given that the well-known non-linearity of the acoustic-articulatory mapping. More detailed investigation of the results indicates that while non-linearity in the acoustic-articulatory mapping affects the recovery of articulatory information for all tongue regions, it contributes considerably more to error in recovering tongue-tip position. For the tongue body, the correlation between predicted and observed tongue body position is approximately 0.9 while the correlation for tongue tip position was approximately 0.65. A linear approximation seems to be sufficient to recover tongue body position with average error of approximately 12%, even with limited acoustic information.
Scattering from highly extended acoustical objects using multiple precision computation
Authors: Feuillade C.
Published: October 2011

The extended boundary condition (or “T-matrix”) technique of Waterman [J. Acoust. Soc. Am., 45, 1417-1429 (1969)] has recently been used to study scattering from highly non-spherical axisymmetric air-filled acoustical objects in water. Evaluation of the T-matrix for extended objects is frequently problematical, typically requiring the inversion of very large and highly ill-conditioned matrices. A second issue is computation of the matrix elements themselves, requiring accurate numerical quadrature of the surface integrals around the scattering object. In this work, a computational scheme was implemented using MATLAB®, and a freely downloadable software package “mptoolbox,” which enables numerical computations to be performed to arbitrary degrees of precision. Here, it was implemented with 250 bits of precision specified for the mantissa part of the number, leading to computations with about 75 decimal places of accuracy. Using a multiple precision method significantly improved the stability and accuracy of both types of operations and indicates a powerful tool for the successful implementation of many scattering and other acoustical problems demanding high precision computational schemes. [Work supported by ONR.]
Acoustic scattering by bubbles in naturally occurring mud sediments
Authors: Pierce Allan D. , Carey Willam M.
Published: October 2011

Naturally occurring sediment mud contains bubbles created by decaying vegetable matter. Work reported by Preston Wilson etal. (ca. 2007) has determined via x-ray tomography systems that mud bubbles are not spherical in shape, but resemble oblate spheroids and are “inhomogeneously distributed.” These features are explained in terms of the card-house structure of mud with an adaptation of the fracture mechanics ideas of Boudreau etal. (ca. 2002). The scattering of sound at low frequencies by such nonspherical bubbles has both monopole and dipole components. The scattered wave associated with the monopole term is proportional to the bubble volume. The dipole term involves an effective entrained mass tensor, which is found by a solution of Laplace's equation. All bubbles, regardless of shape, have a smallest resonance frequency, and the scattered radiation near the resonance frequency is monopole in character. Example solutions for the resonance frequencies and the scattering near resonance are given for oblate spheroidal bubbles, and a suggested interpolation from low frequencies to resonance frequencies is given. A discussion is also given of how one can make use of the range-evolving form of compact-source generated pulses to infer information about the bubbles near the propagation path.
Investigating sources of variability of the range and structure of the low frequency shallow convergence zone
Authors: Lynch Stephen D. , D'Spain Gerald L. , Heaney Kevin D. , Baggeroer Arthur B. , Worcester Peter , Mercer James , Murray James
Published: October 2011

During an experiment in the northern Philippine Sea in 2009, a ship towing Penn State's Five-Octave Research Array (FORA) at approximately 120 m depth drove counter-clockwise in an arc, maintaining constant range at one convergence zone (CZ) from a second ship holding station with an acoustic source deployed at 15 and 60 m. In addition, the FORA was towed at various depths in a star pattern about the station-keeping source ship, thereby sampling the first CZ in range, depth, and azimuth. Throughout the experiment, sound speed profiles were measured using expendable bathy-thermographs, expendable sound velocimeters, and conductivity/temperature versus depth sensors, and detailed bathymetric data were collected using the multibeam systems aboard these and other ships. By incorporating this extensive environmental information into numerical models, variability observed in these measurements of the range and structure and asymmetry of the distribution of received levels of the first CZ resulting from a shallow source to shallow receiver are attributed to variability in the sound speed of the upper-most water column and bathymetry (especially bathymetric features mid-way between the source and receiver). It is found that the sensitivity of the CZ to bathymetry is dependent on the sounds speed in the upper water column.
Unintended consequences of recent changes in ship traffic
Authors: McKenna Megan F. , Wiggins Sean M. , Hildebrand John A. , Ross Donald
Published: October 2011

Underwater ambient noise levels measured off the coast of southern California were correlated with regional changes in commercial shipping trade. Between 2007 and 2010, two events occurred that resulted in a decrease in ship traffic in the Santa Barbara Channel: the economic recession and a coastal air-quality improvement rule. From October 2005 to June 2010, monthly low-frequency ambient noise levels at a site 3 km from a major shipping route were compared to regional traffic levels. Two different metrics of ship traffic showed that on average a 1 dB reduction in low-frequency noise levels resulted from a decrease in traffic by one ship passage per day in a coastal basin.
Monaural and binaural aerial hearing thresholds in a California sea lion (Zalophus californianus)
Authors: Brewer Arial M. , Mulsow Jason , Finneran James J.
Published: October 2011

Though studies have focused on some aspects of binaural hearing in otariid pinnipeds, none have directly measured monaural hearing thresholds. Recent auditory evoked potential (AEP) testing with a young male California sea lion suggested that hearing threshold differences potentially existed between the subject's two ears. To further investigate these findings, aerial psychophysical audiograms were collected for this sea lion. Using headphones to deliver stimuli, monaural and binaural thresholds were measured at seven frequencies from 0.5 to 32 kHz in one-octave steps. The binaural and two monaural (left and right ears) psychophysical audiograms were all similar in that they had the typical mammalian U-shape, with peak sensitivity from 8 to 16 kHz. The right ear showed generally elevated psychophysical thresholds when compared to the left, although all differences were less than 7 dB. The psychophysical and AEP audiograms were similar in terms of shape; however, the directions of monaural threshold differences determined with AEP methods were not always consistent with those obtained using psychophysical methods. [Work supported by ONR.]
Vuvuzelas and their impact
Authors: Cunefare Kenneth A. , Ruhala Richard , Ruhala Laura , Ortkiese Tina
Published: October 2011

Vuvuzelas are inexpensive plastic horns that became a part of the American vocabulary during the 2010 World Cup held in South Africa, though horns of the style have been employed for decades in the States. During the World Cup, spectators played these horns through the games, causing noise complaints from athletes and spectators alike, including television listeners. The vuvuzelas and similar small, plastic horns are sold in the U.S. and other countries, and there is concern that they will create a related noise problem at future sporting events. This work presents the sound pressure levels, spectra, and directivity measured in a hemianechoic chamber produced by several different vuvuzelas, one at a time. Furthermore, a model is developed to predict noise levels within the stands and on the playing field assuming type- and temporal-mixes of the horns.
Discriminating language and talker using non-linguistic measures of rhythm, spectral energy and f0
Authors: Carbonell Kathy M. , Lansford Kaitlin , Utianski Rene , Liss Julie , Lotto Andrew
Published: October 2011

Recent studies have shown that rhythm metrics calculated from amplitude envelopes extracted from octave bands across the spectrum (the envelope modulation spectrum or EMS) can reliably discriminate between spoken Spanish and English even when produced by the same speakers [Carbonell et al., J. Acoust. Soc. Am. 129, 2680]. Additionally, bilingual speakers could be discriminated fairly seven females and five males well on EMS variables even across sentences spoken in the different languages. In the current study, EMS, a general acoustic measure with no reference to phoneme/linguistic entities, was supplemented with measures of the mean and variance of spectral energy in each octave band as well as the mean and variance of fundamental frequency. Using stepwise discriminant analysis and the set of bilingual productions of Spanish and English, it was determined that language discrimination was excellent using both EMS and spectral measures, whereas spectral and f0 measures were most informative for speaker discrimination. The results demonstrate that this suite of easily-calculated acoustic measures provides abundant information about differences between languages as well as inherent differences in speakers that are independent of language spoken. [Work supported by NIH-NIDCD.]
Temporal regularity in speech perception: Is regularity beneficial or deleterious?
Authors: Geiser Eveline , Shattuck-Hufnagel Stefanie , Gabrieli John D. E.
Published: October 2011

Speech rhythm is of crucial importance for correct speech perception and language learning; for example, the specific rhythm is among the first things infants learn about their native language (Ramus, 2000). This study aimed to investigate the importance of speech rhythm in second language learning. German pseudosentences were presented to subjects in two conditions: spoken with a normal conversational speech rhythm versus with a speech rhythm containing a temporally regular beat. Nine native English speakers with 3.5±1.6 years of German training repeated each sentence after hearing it once over headphones. Responses were transcribed using to the IPA and analyzed for the number of correct, false, and missing consonants, as well as for consonant intrusions. The over-all number of correct reproductions of consonants did not differ between the two experimental conditions. However, the experimental condition comprising a normal conversational speech rhythm resulted in significantly fewer consonant intrusions than the condition containing a beat. These results highlight the importance of speech rhythm in language perception/production and suggest, in particular, that second language learning may be facilitated by language-specific temporal grouping. [During the preparation of this work E. G. was supported by the Swiss National Science Foundation (SNF;PBZHP1-123304).]
Stability of compensatory behavior for real-time perturbations of vowel formants
Authors: Mitsuya Takashi , MacDonald Ewen N. , Munhall Kevin G.
Published: October 2011

While we talk, not only do we listen to the speech sounds other people make but also we listen to our own voice in order to control the phonetic/phonological details of the sounds. One example of this relationship is demonstrated by real-time formant perturbation studies which show that talkers automatically change their formant production when auditory feedback does not match with the vowel they intend to produce. The reported results are consistent across studies, yet the variability between talkers is usually quite large, with some talkers showing a large magnitude compensation while others compensate modestly. To date, the degree to which talkers compensate has been assumed to be stable, but this has never been directly examined. The current study tested the stability of compensatory behavior for perturbed formant shifted feedback by repeatedly testing a group of talkers over the course of a few weeks to measure the variance in formant values and compensation across experimental sessions. The results will be discussed in terms of sensorimotor adjustment and speech production models.