bluuebunny/crossref_metadata_2025 huggingface dataset:
Back to vitruvius?
Authors: Lee James B.
Published: March 2010

There is no generally accepted theory of acoustics of concert halls based on the physics of sound as waves. Lord Rayleigh, founder of the science, remarked but little about sound in rooms. Wallace Clement Sabine made an analogy of sound in rooms to the kinetic theory of gases; although this is theoretically untenable, Sabine designed the superb concert hall which is the subject of this session. Leo Leroy Beranek published the first systematic examination of concert halls, demonstrating that subjective evaluations of acoustic quality are consistent: everyone agrees which are good and which are poor; nonetheless Beranek encountered severe difficulty in applying his experimental results. What aspects of the physics of Rayleigh explicate the data of Beranek and the design of Sabine?
Model-based signal processing approach to animal bioacoustics: A brief overview.
Authors: Candy James V.
Published: March 2010

The model-based approach to signal processing is generally founded on the fundamental concept of incorporating any a-priori knowledge of the underlying phenomenology from which the signal evolved along with measurement instrumentation and uncertainty (noise, parameters, etc.) in the form of mathematical models that are embedded in the processor. In this way, the phenomenologist, experimenter, and signal processor combine all of their possible knowledge into a scheme enabling each to think within their own comfort zones while developing a powerful approach to extract the illusive information they desire. In this overview, we present the concepts required to develop mode-based processing schemes that can be used in a wide variety of animal bioacoustics applications ranging from signal estimation, tracking, identification, detection, and classification. We discuss the development of this approach incorporating acoustic applications that can be extrapolated to animal bioacoustics problems. We can express all of these techniques in terms of a model-based framework enabling the use of such powerful estimation techniques such as Kalman filters (Gaussian case) to Bayesian particle filters (non-Gaussian case) for solution to a wide variety of problems.
Identifying delphinid whistle contours using graph search.
Authors: Roch Marie A. , Patel Bhavesh , Rankin Shannon , Barkley Yvonne , Soldevilla Melissa S. , Hildebrand John A.
Published: March 2010

The automated characterization of delphinid whistle contours can lead to insights (both potential and realized) into biological questions such as habitat use and behavior. Prior to the 1990s, most measurements of whistle contours were conducted manually by trained analysts, and even today the noisy signal environment offers significant challenges to fully automated classification systems. In this talk, we provide an overview of challenges and historical approaches to this problem. We present our recent research using graph search algorithms to characterize complex auditory scenes involving numerous animals vocalizing simultaneously. We end by discussing techniques that have the potential to further advance this area of research. [Work sponsored by ONR.]
Travel time inversion of broadband data from Shallow Water 2006 experiments.
Authors: Jiang Yong-Min , Chapman N. Ross
Published: March 2010

This paper presents geoacoustic inversions of broadband signals collected by the L-shaped array SWAMI32 during the Shallow Water 2006 Experiments. The L-shaped array was deployed in 70 m of water off the coast of New Jersey. The vertical leg of the array (VLA) has 10 even spaced sensors which expends 53.55 m in the water column, while the horizontal leg (HLA) has 20 uneven spaced bottom moored sensors that give 256.43 m of the aperture. An acoustic source was maintained at a depth of 35 m and towed along a circle around the VLA at a speed of 0.5 knots. The distance between the acoustic source and the VLA was around 190 m. Mid-frequency (1100–2900-Hz) chirps received at the VLA and HLA were analyzed for investigating the variability of the sea bottom properties around the circle. The data at the HLA were analyzed to assist the identification of the bottom layer structure while the data at VLA were employed to carry out the geoacoustic inversion. Environmental data collected in the vicinity were used in the inversion to account for the variable water column environment. [Work supported by ONR Ocean Acoustics.]
The card-house structure of mud: Energy between particles and its effect on bubble formation.
Authors: Fayton Joseph O. , Pierce Allan D. , Carey William M. , Siegmann William L.
Published: March 2010

A model of mud as a lyophobic colloid [Verwey and Overbeek (1948)] leads to a card-house structure of platelets, typically kaolinite or smectite particles. Because of isomorphous substitution, each platelet carries a distributed negative charge. The structure is immersed in water which, especially so for sea water, carries positive and negative ions, and the positive ions tend to cluster on both sides of the platelets, so that the composite platelet charge is zero, but each platelet is analogous to a sheet of longitudinal electrical quadrupoles. The charge distribution causes parallel platelets to repel each other, but which can attach so that one platelet edge can touch the face of another platelet. The energy associated with such attachments is discussed, and it is conjectured that it is associated with van der Waals and London attraction forces. Recent sound transmission experiments by Carey at Dodge Pond in Connecticut support the contention that sediment mud invariably contains vapor bubbles, and other work such as that of Boudreau et al. (2005) suggests that the bubbles are considerably flattened, with shapes that have been described as corn-flakes. Present paper conjectures as to whether these shapes are associated with the card-house structure of mud.
Tank experiments for validation of volume scattering models.
Authors: Quijano Jorge E. , Zurk Lisa M.
Published: March 2010

Mid-frequency scattering from random media is of interest for active sonar applications and, in particular, in shallow water environments, where ocean bottom interaction may affect the performance. To estimate the contribution of volume scattering from the sea bed, models based on the wave equation have been developed and more recently, an approach based on transport theory was proposed [J. Acoust. Soc. Am. 126, 1711–1723 (2009)]. Validation of this model is difficult to achieve in field experiments due to environmental uncertainties and in many cases to the lack of ground truth revealing the structure of the random media. As an alternative, tank experiments were implemented in a controlled environment at scaled frequencies to explore the range of applicability as a function of different input parameters such as frequency of operation, scatterer size, and concentration. For this work, gel slabs containing random distributions of micron-sized glass beads were manufactured, and broadband pulses at the frequency band 200–600 kHz were utilized to characterize the scatterer contribution. Acoustic propagation through this heterogeneous media is analyzed using the proposed radiative transfer method and the results are compared to the analytical solution of the wave equation for the long-wavelength approximation.
Temporary modulation of vascular barriers with focused ultrasound and microbubbles.
Authors: McDannold Nathan
Published: March 2010

The combination of focused ultrasound and preformed microbubbles (ultrasound contrast agents) circulating in the bloodstream provides an opportunity to utilize mechanical stimulation of endothelial cells to temporarily and locally modulate transvascular transport and permeability. This stimulation may directly alter the endothelium and increase free transport of agents out of the vasculature or it may trigger a physiological response and increase active transport. This talk will review recent work in the brain and kidney utilizing low-intensity focused ultrasound bursts and microbubbles to temporarily disrupt barriers to transvascular passage. In the brain, these sonications result in a temporary disruption of the blood-brain barrier and potentially enable a means for targeted drug delivery. Recent work will be shown demonstrating that the method is sensitive to anesthesia agent, perhaps due to differences in vasoactive effects. In the kidney, we have found that these sonications result in a temporary increase in glomerular filtration rate and urine production and the ability to temporarily pass larger molecules, potentially providing a new platform for the study, and perhaps treatments, of renal disease. Overall, the interaction between ultrasound, microbubbles, and the endothelium presents a unique means to interact with blood vessels and provides opportunities to develop novel treatments.
Controllable plasma membrane poration by pulsing tandem microbubble.
Authors: Sankin Georgy , Yuan Fang , Zhong Pei
Published: March 2010

Understanding the dynamic interaction of cavitation bubbles with biological tissue is central to the effective and safe application of therapeutic ultrasound in clinical medicine. Coupled oscillation of two laser generated microbubbles (maximum radius = 28 μm) in constrained media and associated shear stresses are investigated experimentally. Bubble-bubble interaction in a microchannel of 25-μm height is observed using high-speed video cameras and μPIV technique. Two liquid micro-jets moving in opposite directions can be generated when the second bubble is produced at the maximum size of the first one. The interaction of these tandem microbubbles with single cell leads to controllable poration of adjacent cell membrane and dye uptake. Micro-PIV data are compared with cell viability at various bubble-cell distances and azimuthal orientations. This method provides a new approach for highly selective cell treatment in situ applicable to targeted microinjection of macromolecules and gene vectors in microfluidics devices. [This work was supported in part by NIH.]
A new loudspeaker design for the enhancemenet of sound image localization on flat display panels.
Authors: Pablo Nava Gabriel , Hirata Keiji , Shirai Yoshinari
Published: March 2010

In most audio-visual multimedia applications, conventional stereo loudspeakers have been used to implement auditory displays. However, a fundamental problem with this kind of displays is that only the listeners situated at the sweet spot and over the symmetrical axis of the loudspeaker array are able to accurately localize the sound images. Although a number of audio signal processing algorithms have been proposed to expand the listening area, relatively less study on new loudspeaker configurations has been explored. This paper introduces a simple, yet effective, loudspeaker design to enhance the localization of sound images over the surface of flat display panels. In contrast to previous approaches, expansion of the listening space is achieved by attachment of rigid barriers which physically modify the sound radiation pattern of the loudspeakers. Moreover, numerical simulations, experimental sound measurements, and subjective tests have been preformed to validate a prototype of the proposed loudspeaker design using a display panel of an immersive teleconferencing system. Finally, an example of an interactive application was implemented involving real-time speaker tracking with a microphone and video cameras.
The influence of matching layer material loss on radiation impedance conversion in ultrasonic transducers.
Authors: Toda Minoru
Published: March 2010

PZT based thickness mode ultrasonic transducers for both air and water/tissue typically have a quarter wavelength front matching layer with impedance Zm. It is widely known that the lower acoustic impedance ZR of the propagation medium is converted to a higher impedance at the PZT surface by the relation Zmax = Zm2/ZR (quarter wavelength conditions). In this work, the converted impedance was accurately calculated using a transmission line model incorporating the mechanical quality factor Qm of the matching layer material. In a medical transducer, it was found that the peak value is 20% or 28% lower than Zmax = Zm2/ZR for Qm = 15 or 10, respectively. For air transducers, the peak value is one to two orders lower than Zmax for the same range of Qm. These Qm values are typically observed for the filled epoxy matching layer materials used in medical transducers and also for porous or air entrained materials used for air acoustic transducers. A simple impedance conversion equation for an air transducer has been proposed, making the design of air impedance matching layers easier and suggesting that neglecting material loss leads to serious errors.
Transitory response of an acoustic levitator.
Authors: Shakir Sahir , Thompson Charles
Published: March 2010

This work will examine the transitory response of an acoustic levitator. Simulations will be used to ascertain the relationship between viscous and inertial forces on the vertical conveyance of a solid projectile. The objective is to use standing waves of strong intensity in a cavity to elevate a solid projectile. The projectile is suspended by nonlinear acoustic forces, and by rate of change in the frequency, amplitude, or cavity length, the transitory response will be determined.
An ultrasonic vibrator constructed from laminated Galfenol steel.
Authors: Porter Scott P. , Thompson Stephen C. , Meyer Richard J.
Published: March 2010

An ultrasonic vibrator has been developed to serve as the drive mechanism for an electroacoustic transducer. This design explores the unique characteristics of Galfenol, a recently invented giant magnetostrictive material. In addition to possessing competitive strain capabilities, strong mechanical properties, and a high-magnetic permeability, Galfenol does not require a prestress mechanism and can be laminated to effectively mitigate eddy current losses. Designing the vibrator required the authors to carefully engineer the magnetic circuit so that proper bias fields could be established using a permanent magnet. This step will be demonstrated with one- and two-dimensional models. Drive coil considerations will also be discussed and the fabrication and assembly of the vibrator will be shown along with in-air measurements.
What can we learn from statistics on acoustics?
Authors: Ivie Rachel
Published: March 2010

This talk will present current statistics on acoustics degrees and employment in acoustics. The data come from the National Science Foundation’s studies of degrees awarded and from the American Institute of Physics’ surveys of members of our ten Member Societies (including ASA). Because acoustics encompasses many different disciplines, these statistics will be compared to data from larger fields such as engineering, physics, and life and earth sciences. Although the numbers are very small in acoustics, data will be shown on the participation of under-represented minorities and women where possible. Finally, implications for increasing diversity in acoustics will be discussed.
Diversifying physics: Legal context, education action.
Authors: Chubin Daryl E.
Published: March 2010

Science education and career development are vital for (1) driving innovation and economic strength, (2) US leadership in producing research & development and the personnel responsible for its renewal, and (3) shaping federal investments in what universities do and K-12 schools teach. Yet the nation faces a demographic challenge: by 2042, the population will be “majority minority.” Minorities represent less than 7% of the nation’s STEM workforce and are grossly underrepresented in undergraduate and graduate degrees awarded in STEM fields. In addition, the US is flagging in STEM degree production compared to the nations of Europe and Asia. Regardless of one’s political beliefs, the nation must prepare more of its citizens for careers in science and engineering. This lecture focuses on the legal climate for increasing participation of underrepresented groups (women and minorities) in physics education and careers. Review of student- and faculty-centered programs and practices that have been “effective” in research universities face another challenged: Can they be made “legally sustainable”? How to make progress “on the ground” in the face of what the law calls—for disciplines such as physics and specialties such as acoustics—a “pipeline problem” will be discussed.
Molecular dynamics of nonlinear and nonequilibrium effects in sound propagation.
Authors: Yano Takeru
Published: March 2010

Nonlinear and nonequilibrium effects on the propagation process of large amplitude and high-frequency sound waves are studied with the method of molecular dynamics, where the whole physical phenomenon is described in the numerical solution of Newton’s equation of motion for hundreds of thousands of gas molecules. The frequency of sound studied here is so high that the wavelength should be comparable with the mean free path of gas molecules, and hence the continuum theory cannot be applied to the resulting phenomenon. The wave profiles are obtained by averaging the molecular motions, and the most conspicuous nonlinear effect in the result is the mass and energy transports by a shock-like wave, for which the origin can be attributed to a nonequilibrium effect caused by the high-frequency sound. The nonequilibrium effects are quantitatively examined with the velocity distribution function of gas molecules.
Materials science at extreme conditions.
Authors: Belak James
Published: March 2010

The response of a material to an extreme stress transient is sensitive to the loading path and the rate of loading. An extreme example is following a phase transformation, during which the microscopic structure of the material completely rebuilds itself. This microstructure, to a large degree, determines the further response of the material. Traditionally, microstructures have been measured by slicing up the pieces and looking inside with methods such as scanning electron micrsocopy and transmission electron micrsocopy. However, at extreme conditions, such as following a phase transformation, one cannot pick up the pieces and must resort to non-destructive probes such as x-ray scattering. Here, we review recent attempts to determine shocked microstructures using non-destructive diffuse and small-angle x-ray scattering and compare to large-scale molecular dynamics simulations. The talk will anticipate future experiments at emerging light sources such as the Linac Coherent Light Source. [This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.]
The influence of shock loading on material properties and dynamic damage evolution.
Authors: Cerreta Ellen K. , Gray George T. , Koller Darcie D. , Bronkhorst Curt A. , Trujillo Carl P. , Hansen Benjamin L.
Published: March 2010

Many commercial and defense applications require structural metals for extreme environments. Specifically, automotive, aerospace, and infrastructure applications need materials with damage tolerance during dynamic loading. To this end, many studies have examined dynamic deformation and damage evolution. These studies have shown that kinetics of loading are critically important to damage evolution of bulk metals. Particularly, in dynamic loading environments in which a shock wave is imparted to the metal, kinetic and spatial effects based on shock wave shape play important roles in damage. These studies also show that depending on crystal structure, shock loading can alter the subsequent properties of a material significantly. However, while these phenomena are gaining acceptance in the dynamic damage community, the ability to predict these phenomena is limited. Here, the influence of dynamic loading across strain rates 103–106/s will be discussed. The role of test platforms and crystallography to examine the influence of kinetics will be tied to changes observed in deformation and damage evolution. It can be shown that isolating the influence of spatial and kinetic effects during dynamic loading is critical to understanding dynamic damage evolution and with this understanding, capabilities for predicting dynamic damage evolution can be advanced.
Acoustical shock formation in highly nonlinear fluids.
Authors: Pantea Cristian , Sinha Dipen N.
Published: March 2010

Weak shock formation is investigated for plane sound waves of finite amplitude in fluids with high-acoustical nonlinearity. The shock formation length is related to the sound speed of the fluid c and its nonlinear parameter B/A. The use of fluids with low-sound speed and high parameter of nonlinearity has the advantage that the shock formation can be achieved at much lower pressures. Also, the experiments can be done on a smaller scale because the shock formation length is relatively small. The experiments are performed using short pulsed sound beams produced by a planar transducer with a resonance frequency of 0.5–1 MHz. The propagation medium consists of either different types of fluorocarbon or methanol. Direct pressure measurements of the acoustic waves in the fluid were obtained using a high-frequency calibrated hydrophone. For comparison, a relatively smaller acoustical nonlinear material like water is also investigated. Experimental results related to second and higher harmonics generated in the fluid and their evolution in time along the propagation axis are compared with theoretical time-domain predictions of the Khokhlov–Zabolotskaya–Kuznetsov equation.
Neural substrates of spontaneous musical improvisation.
Authors: Limb Charles J.
Published: March 2010

To investigate the neural substrates that underlie spontaneous musical performance, functional MRI was used to study improvisation in professional jazz pianists. The purpose of the study was to identify the neural substrates that give rise to spontaneous musical creativity, defined as the immediate, on-line improvisation of novel melodic, harmonic, and rhythmic musical elements within a relevant musical context. It was hypothesized that spontaneous musical improvisation would be associated with discrete changes in prefrontal activity that provide a biological substrate for actions that are characterized by creative self-expression in the absence of conscious self-monitoring. By employing two paradigms that differed widely in musical complexity, it was found that improvisation (compared to production of over-learned musical sequences) was consistently characterized by a dissociated pattern of activity in the prefrontal cortex: extensive deactivation of dorsolateral prefrontal and lateral orbital regions with focal activation of the medial prefrontal (frontal polar) cortex. Such a pattern may reflect a combination of psychological processes required for spontaneous creative behaviors such as improvisation, in which internally motivated, stimulus-independent behaviors unfold in the absence of central processes that typically mediate self-monitoring.
Measuring and predicting the quality of nonlinearly distorted music and speech as perceived by hearing-impaired people.
Authors: Tan Chin-Tuan , Moore Brian C. J. , Svirsky Mario
Published: March 2010

The goals of this study were to characterize and model the perception of nonlinearly distorted speech and music by hearing-impaired listeners. Hearing-impaired listeners were asked to rate the perceived quality of speech and music that had been subjected to various forms of nonlinear distortion, some of which are inherent to certain hearing aid designs including (1) hard and soft, symmetrical and asymmetrical clipping; (2) center clipping; (3) “full-range” distortion, produced by raising the absolute magnitude of the instantaneous amplitude of the signal to a power (8800;1), while preserving the signal of the amplitude; (4) automatic gain control (AGC); (5) output limiting. Stimuli were subjected to frequency-dependent amplification as prescribed by the “Cambridge formula” before presentation via Sennheiser HD580 earphones. The pattern of the rating was reasonably consistent across subjects with only two of ten subjects not making consistent ratings. The mean ratings were not lower with increasing amount of soft or center clipping or when the compression ratios of the AGC and output limiting were increased. The deleterious effects produced by these nonlinear distortions may have been offset by the beneficial effects of improving audibility and compensating for loudness recruitment. [Work supported by Deafness Research Foundation.]
A novel physiological mechanism for pitch encoding in monkey primary auditory cortex.
Authors: Fishman Yonatan I. , Steinschneider Mitchell
Published: March 2010

Pitch is a fundamental perceptual attribute of hearing. While auditory cortex is implicated in pitch perception, how pitch is represented at the cortical level remains unclear. The present study examines a novel hypothesis for how the pitch of pure tones and of harmonic complex tones, with or without the fundamental frequency, is encoded in primary auditory cortex (A1): pitch is represented non-topographically by the temporal distribution of population activity in A1. Sounds of lower pitch evoke a greater proportion of sustained multiunit activity (MUA), relative to initial onset MUA, than sounds of higher pitch, such that the temporal distribution of MUA systematically varies with pitch. Pure tones and harmonic complexes with the same pitch evoke a similar proportion of sustained MUA. The temporal distribution of MUA is largely invariant to changes in stimulus parameters (e.g., level and relative phase) that leave the perceived pitch unchanged. Timing of AEP components recorded in superficial layers of A1 parallels similar pitch-related changes in AEPs recorded in humans. Coding of perceptual qualities based on the time course of neural activity has been proposed in other sensory modalities (e.g., olfaction) and offers a novel alternative to topographic representations of pitch at the cortical level.
Coherent backscattering enhancement in cavities. Highlight of the role of symmetry.
Authors: Gallot Thomas , Catheline Stefan , Roux Philippe
Published: March 2010

Through experiments and simulations, some consequences of symmetry on coherent backscattering enhancement (CBE) in cavities are reported here. First, CBE outside the source is observed (a) on a single symmetric point in a one dimensional cavity, in a tw0-dimensional (2-D) circular membrane, and in a 2-D symmetric chaotic cavity; (b) on three points in a rectangle; and (c) seven in a parallelepiped. Second, existence of enhanced intensity lines and plans in 2-D or three-dimensional cavities is demonstrated. Third, we show how antisymmetry is responsible for the existence of a coherent backscattering decrement with a dimensional dependence of (12)d law, d being the dimensionality of the cavity.
Cue weighting and variability in perception and production.
Authors: Hwang Jiwon
Published: March 2010

The Korean single liquid phoneme shows an allophonic variation: lateral [l] occurs in coda and tap [r] in onset. Intervocalically, they may appear contrastive as tap or geminate lateral [ll] ([iri] wolf vs [illi] reason), differing in duration and laterality. Kim [(2007)] demonstrated that Korean listeners identified a shortened geminate lateral as geminate /ll/ rather than tap, despite the fact that the duration of edited stimuli was matched for tap. The current study examines whether the weighting of laterality cues over duration cues for [ll] vs [r] is motivated by the native language acoustics. Korean speakers produced 24 Korean words [(C)V_V], containing [ll] or [r] in two speech modes (in a carrier sentence vs in isolation). The duration of [ll] was significantly longer than tap, but it varied greatly depending on the speech mode while tap did not. The intensity of tap was significantly lower than [ll] generally, but it showed a greater variability. However, F3 at the offset of the preceding vowel was lower for tap than for [ll] regardless of the speech mode. The consistent use of F3 in production supports the perceptual cue weighting pattern where Korean listeners rely more on spectral cues than duration for intervocalic [ll]-[r] contrast.
The discrimination, perception, and production of two German /r/ allophones by two groups of American English speakers.
Authors: Tepeli Dilara
Published: March 2010

The German /r/ sound is one of the most difficult sounds for American English (AE) speakers learning German as a foreign language. Part of this difficulty may be due to its rich phonetic variation. The standard German /r/ variant [R] and dialectal variant [R′] are achieved by varying the tongue constriction degree while keeping place of articulation constant [Schiller and Mooshammer (1995)]. The close articulatory proximity of these allophones provides an opportunity for testing the relationship between perception and production in L2 sound acquisition. The aim of this study is to investigate how well experienced AE speakers and naive AE speakers can discriminate and produce the difference between the uvular fricative [R] versus the uvular trill [R′]. Two groups of AE subjects who participated in an imitation study were prompted to produce single words beginning with either [R] or [R′]. Subjects also participated in a discrimination and categorization test. Preliminary results suggest that inexperienced AE can discriminate [R] versus [R′] well. They often perceive the sounds as /h/ and are more successful at producing [R′] than [R]. Experienced speakers also discriminate the two sounds well, perceive both sounds as the German /r/ and struggle more with producing [R′] than [R].
Auditory feedback shifts in one formant cause multi-formant responses.
Authors: Katseff Shira , Houde John F. , Johnson Keith
Published: March 2010

Talkers are known to compensate for experimentally-induced shifts in auditory feedback. In a typical experiment, talkers might hear their F1 feedback shifted (so that [ε] sounds like [æ], for example), and compensate by lowering F1 in their subsequent speech. Typically, compensation is assumed to directly oppose the action of the feedback shift and is measured in terms of the shifted parameter. In this study, we instead find that sensitivity to altered auditory feedback is multidimensional: subjects respond to altered F1 feedback by changing their F2 production and vice versa. In particular, subjects whose [i] is heard as [ɪ], a shift primarily in F1, compensated by producing a higher F2, while subjects whose central vowel [ʌ] was heard as [ε] or [o], a shift primarily in F2, compensated by producing a higher or lower F1. We argue that it is insufficient to consider auditory sensitivity in terms of a single formant and suggest that this method of altering auditory feedback is a practical tool for investigating the psychological reality of formants and their combinations.
The perception and acoustic features of Korean ditropic sentences.
Authors: Yang Seung-yun , Ahn Ji Sook , Van Lancker Sidtis Diana
Published: March 2010

Ditropic sentences are utterances that convey either a literal or an idiomatic meaning (e.g., It broke the ice). This study investigated listener’s ability to discriminate between literal or idiomatic meanings and examined the acoustic features contributing to this distinction. Ten ditropically ambiguous Korean sentences were audio-recorded by four native speakers of Korean. Each utterance was produced twice with either a literal or idiomatic meaning. Fifteen native Korean subjects listened to a randomized presentation of these utterances singly and in pairs without other context and identified each as literal or idiomatic. Listeners successfully discriminated the intended idiomatic or literal meanings (singletons = 70.65%, pairs = 75.67%). These results were consistent with those of Van Lancker and Canter [(1981)] for English ditropic sentences. Each utterance was acoustically analyzed in terms of means and variations in fundamental frequency, duration, and intensity. Analyses of variance revealed significantly longer durations and greater variation in syllable duration for literal than idiomatic sentences, whereas idiomatic sentences were characterized by significantly greater variation in intensity than literal sentences. Some prosodic cues for Korean differed from those found previously for English [Van Lancker et al. (1981)] and French [Abdelli-Baruh et al. (2007)]. These results further understanding of use of prosody in sentential linguistic contrasts.
Effects of listener experience with foreign accent on perception of accentedness and speaker age.
Authors: Rodrigues Paul , Nagao Kyoko
Published: March 2010

The current study examined the effects of foreign accent and listener experience on the perception of a speaker’s age and native language. Ten audio stimuli were prepared from the recording of five Arabic speakers and five English speakers (18–79 years old) from the Speech Accent Archive [Weinberger (2009)] for the perception experiment. Thirty native speakers of English participated in the perception experiment through Amazon’s Mechanical Turk website, estimated the speaker age, rated the speaker’s accentedness, and estimated the native language of the speaker. The listeners were divided into two groups based on their experience with foreign accented English (experienced and inexperienced groups). Higher correlation was found between perceived age (PA) and actual chronological age (CA) for the native (English) stimuli than for the Arabic-accented stimuli in both listener groups. The correlation between PA and CA was higher in the experienced listeners than in the inexperienced listeners. Accentedness rating suggests that the inexperienced listeners tend to rate both native and non-native speakers neutrally on the scale. The results suggest that experiences with any foreign accented speech facilitates identification of age from speech and help to form the ability to perceive differences in the degree of foreign accented speech.
Why [spa] not [psa]? On the perceptual salience of initial /s/-stop and stop-/s/ sequences.
Authors: Syrika Asimina , Edwards Jan , Fourakis Marios , Kong Eun Jong , Munson Benjamin , Beckman Mary E.
Published: March 2010

Initial /s/-stop clusters occur frequently in the world’s languages, but initial stop-/s/ clusters are relatively infrequent. Furthermore, there appear to be no languages that contain initial stop-/s/ clusters, but not /s/-stop clusters, while the reverse is not true [Morelli, (1999) and (2003)]. This study aims at uncovering a perceptual explanation for these patterns by examining the salience of initial /s/-stop and stop-/s/ clusters in Greek, where both sequences are common. Twenty naïve Greek adult listeners identified syllables beginning with /sp/, /st/, /sk/, /ps/, /ts/, or /ks/, in two vowel contexts, /a/ and /i/, in real words spoken by ten Greek adult native speakers. The syllables were mixed with parts of Greek multitalker babble using SNRs of −6, 0, and +6 dB and presented to listeners for identification. Results showed significantly poorer identification for the /ps/ and /ks/ clusters than the /ts/ and /s/-stop clusters, particularly in the −6 and 0 SNRS. There was also a significant interaction with vowel, such that /sk/ and /ts/ were identified more accurately before /a/, whereas /ks/ was identified more accurately before /i/. The implications of these findings for phonological acquisition and speech perception are considered. [Work supported by NIDCD 02932 and NSF Grant 0729140.]
Individual differences in use of English fricative perceptual cues.
Authors: Casserly Elizabeth
Published: March 2010

This study examines individual variation as a potential explanation for contradictory and inconsistent reports of English speakers’ use of acoustic cues in identification of the voiceless sibilants [s] and [∫]. While there is widespread agreement that the spectral shape of turbulent noise is key for identification of these two categories, some studies find that formant transitions to and from the noise also influence identification [Whalen, J. Acoust. Soc. Am. 69, 275–282 (1981)], while others do not [Harris, Lang. Speech 1, 1–7 (1958)]. Similarly, the majority of studies investigating the effect of vowel context on fricative perception show that the presence of round vowels biases listeners toward perception of [s] [Kunisaki and Fujisaki, Ann. Bull. RILP 11, 85–91 (1977)], but others show precisely the opposite effect, where round vowels favor [∫] responses [Nittrouer and Studdert-Kennedy, J. Speech Hear. Res. 30, 319–329 (1987)]. In this study, 30 native English speakers participated in a labeling experiment that fully crossed all three factors—spectral noise shape, formant transitions, and vocalic context—for each subject. Every pattern of cue use found in the literature is also found in one or more of the individuals, which may explain why averaged results vary so widely across reports.
Initial acoustic-phonetic processing of competing verbal stimuli examined using dichotic verbal transformations.
Authors: Lenz Peter W. , Bashford James A. , Warren Richard M.
Published: March 2010

Initial studies with dichotic verbal transformations (VTs) of repeating words employed a cross-ear asynchrony of half the word’s duration and listeners called out the independent perceptual changes at each ear as they occurred. In contrast to monaural and diotic VTs, the dichotic “immediate response” procedure is extremely difficult and tiring, requiring concurrent monitoring while remembering the word previously heard on each side. The present study employs a much less demanding task—a cued report procedure: the listener calls out what is heard on each side when prompted by a periodic light flash. When the asynchronous stimuli were statements of the same word, the transition rates on each side were the same as when presented monaurally, in contrast with the decreased rates reported with the earlier procedure. With different words on each side, the transition rates were diminished by an amount depending on the extent of their phonetic differences—rates were not influenced by either semantic relations or differences in the neighborhood density of the competitors. It is suggested that dichotic verbal transformations provide access to aspects of the acoustic-phonetic front end of speech analysis that may be obscured by subsequent levels of processing. [Work supported by NIH.]
Bayesian approach to model-based signal processing: An overview.
Authors: Candy James V
Published: March 2010

Although available for a long time with the advent of high-speed/high-throughput computing, the development of Bayesian processing techniques has evolved recently in acoustical signal processing. Bayesian signal processing is concerned with the estimation of the underlying probability distribution of a random signal in order to perform statistical inferences such as the conditional mean estimation. Knowledge of this distribution provides all of the essential information available required for problem solution. The usual limitations of nonlinear approximations and non-gaussian processes prevalent in classical algorithms (e.g., Kalman filters) are no longer a restriction to perform Bayesian inference. This approach enables the next generation of processors called particle filters that are sequential Monte Carlo methods providing an estimate of the underlying discrete probability distribution. In this overview, Bayesian signal processing is presented from a probabilistic perspective starting with Bayes rule and evolving to the development of a bootstrap particle filter perhaps one of the most common and simplest constructs available. The relationship of Bayesian processing to the concept of maximum entropy is discussed. Maximum entropy and its applicability in Bayesian processing is also mentioned briefly.
Bayesian bounds on passive sonar accuracy from binary performance metrics.
Authors: Buck John R.
Published: March 2010

A passive sonar algorithm measures the pressure field at a sensor array then estimates the sound source location from these observations and an acoustic propagation model. Passive sonar performance is usually characterized by the mean squared error (MSE) between the estimated and true source locations. Consequently, passive sonar performance bounds typically provide lower bounds on the achievable MSE for a given array and environment. Such MSE bounds can be misleading in environments with strong sidelobes, as the optimal estimator may choose an unlikely location to balance the error among several highly likely locations. An alternative algorithm would be to partition the search space, then use the array observations to choose which block contains the source, but not its exact location in the block. The resulting binary performance metric is now the probability of choosing the incorrect block or error probability (Pe). Information theory allows us to formulate Bayesian bounds on the minimum achievable Pe for a given array, propagation environment, and search space partition. These bounds quantify the trade-off among SNR, Pe, and location estimation accuracy for passive sonar. [Work supported by ONR Code 321US.]
Recursive Bayesian state estimation for passive sonar localization.
Authors: Jemmott Colin W. , Culver R. Lee
Published: March 2010

A model-based recursive Bayesian signal processing framework is shown to localize a moving source emitting a low-frequency tonal signal in a shallow water environment. Source motion maps spatial variation in transmission loss into amplitude modulation of the signal received on a passive horizontal array. Acoustic propagation modeling predicts this variability, which is used to estimate source range, depth, range rate, and acoustic level. Uncertainty in transmission loss resulting from uncertainty in environmental parameters is predicted using Monte Carlo modal propagation modeling. Monte Carlo marginalization over environmental uncertainty provides robustness against data-model mismatch. The maximum entropy method is used to construct a probability density function (pdf) of transmission loss at each range depth location based on the Monte Carlo results. The resulting pdfs belong to the exponential family and result in an implementable recursive Bayesian processor. The physics of acoustic modeling determine the form of the processor through the transmission loss pdfs and are an intimate part of the localization technique. This processor is distinct from Bayesian matched field processing in that it neither relies on a vertical array nor computes modal amplitudes from received data. Results using SWellEx-96 will be shown. [Work supported by ONR Undersea Signal Processing.]
Seismo-acoustic propagation near low-shear speed poroelastic ocean sediments using a hybrid parabolic equation solution.
Authors: Collis Jon M.
Published: March 2010

Accurate and efficient parabolic equation solutions exist for complex propagation environments featuring elastic and porous elastic sediment types. An area of concern has been low-shear wave speed sediments that become singular as their shear modulus tends toward zero. A historic approach for treating sediments of this type has been to assume that it is a fluid, and effects due to elasticity are negligible. This approach is limited in accuracy unless shear is accounted for. In this presentation, the ocean bottom sediment interface layer is treated as a porous elastic layer in which poroelastic momentum equations are solved and combined with an existing elastic parabolic equation implementation. Appropriate boundary conditions are enforced at the fluid-poroelastic and poroelastic-elastic interfaces. The new solution is tested on problems with a low-shear ocean bottom interface layer.
Experimental studies of underwater acoustic communication in Trondheim fjord.
Authors: Zhang Guosong , Dong Hefeng , Hovem Jens M.
Published: March 2010

Direct-sequence spread-spectrum signal was used for communication tests over underwater channels in Trondheim fjord. Differential binary phase shift keying was utilized between two adjacent symbols. To the receiver, a method uses a time updated channel impulse response estimation to recover differential phase modulated information, and it takes the estimation from the previous symbol as the match filter. The effectiveness of this method is ensured by the coherence between two consecutive symbols over time varying channels. This method is insensitive to multipath patterns, and it does not require time synchronization as precise as the convention de-spread method does. In our experiments, good performance was achieved, even in low SNR tests. The performance loss at high SNR in the experiments was caused by long time delay spread. Late-arriving paths from the previous symbol were buried in the current symbol during time-windowing process, and the late-arriving paths might decrease the magnitude of the differential phase information. In this situation, it is prone to cause errors.
But how does it look?
Authors: Britton Deb
Published: March 2010

As acousticians and audio professionals, we are constantly striving for the “optimum sound solution.” Quite often our optimum solution is at odds with the room’s architecture or the desired aesthetic. This paper will present some examples of spaces where high-quality sound, even coverage, speech intelligibility and visual aesthetics were all achieved.
Recognition of killer whale individuals from multiple stereotyped call types.
Authors: Nichols Nicole , Atlas Les , Bowles Ann , Roch Marie
Published: March 2010

Recognition of marine mammal individuals will be an essential tool for obtaining demographic information of populations as habitat monitoring is increasingly being conducted with passive acoustics. Our previous research established the potential to identify killer whale individuals with passive acoustic recordings with up to 78% accuracy. The data for this result consisted of 75 vocalizations from four adult (two male, two female) killer whales of Icelandic origin in residence at SeaWorld San Diego. The stereotyped vocalizations used were all SD1a or SD1b, and caller identification was known to a high degree of certainty allowing for quantifiable validation. Classification was performed with 12 mel-frequency cepstral coefficients, and 12 delta and 12 delta-delta cepstral coefficients as inputs to a Gaussian mixture model. We initially chose to use one call type as the SD1 call was frequently produced by all four individuals and it eliminated potential ambiguity from identifying call type instead of individual. In the research we now present, we extend our prior methods to be used with multiple call types. Because individuals in the wild will not have a known frequency of call type usage, we propose a normalization method for training a classifier that is unbiased with respect to call-type frequency.
Echolocation behavior of pairs of flying Eptesicus fuscus recorded with a Telemike microphone.
Authors: Bates Mary E. , Watanabe Yu , Furusawa Yuto , Fujioka Emyo , Hiryu Shizuko , Riquimaroux Hiroshi , Knowles Jeffrey M. , Simmons James A.
Published: March 2010

Four big brown bats (Eptesicus fuscus) were flown singly and in pairs in a room containing a sparse array of vertically hanging plastic chains as obstacles. Each bat carried a lightweight radio telemetry microphone (Telemike) that recorded their emitted echolocation sounds without artifacts from Doppler shifts, directional effects, and atmospheric attenuation. The broadcasts of both bats were also recorded with two stationary ultrasonic microphones located at the far end of the flight room. The echolocation broadcasts of bats flying singly were compared to those emitted when the bats were flown together. The principal change was shifting of harmonic frequencies very slightly (<5 kHz) away from each other and from frequencies used when flying alone. In contrast, the duration of emissions was more stable between single and double bat flights. Changes in ending frequency have been associated with a jamming avoidance response in big brown bats and could indicate attempts to avoid interference while flying with conspecifics in an enclosed space. [Work supported by ONR and NSF.]