bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding foreign-accented speech
Authors: Bradlow Ann
Published: October 2013

Why is foreign-accented speech hard to understand? In one view, foreign-accented speech intelligibility is poor due to its marked deviation from the native talker norm. An alternative view claims that if the talkers and listeners shared knowledge systems are sufficiently aligned with each other, foreign-accented speech intelligibility can be good despite its deviation from the native talker norm. Results from two studies in support of this latter alternative will be presented. Study 1 investigated whether intelligibility of Chinese-accented English could be improved for native English listeners through perceptual training. This study showed that if given exposure to multiple talkers of Chinese-accented English during training, native English listeners could achieve talker-independent adaptation to Chinese-accented English. Study 2 compared intelligibility of foreign-accented and native-accented English for non-native and native listeners. Results showed that native listeners found native-accented English more intelligible than foreign-accented English, but non-native listeners found foreign-accented English as intelligible as native-accented English. Interestingly, this pattern was obtained even for non-native listeners and talkers from different language backgrounds. Taken together, these findings demonstrate that intelligibility of foreign-accented speech varies depending on the degree of talker–listener attunement rather than on the extent of its deviation from a native talker norm per se.
Please understand me: Toward modeling of non-native speech in automatic speech recognition
Authors: Mayfield Tomokiyo Laura
Published: October 2013

Non-native speech represents a fundamental challenge for automatic speech recognition (ASR). Most major advances in ASR technology assume consistency in certain features that native speakers of a language share, such as coarticulatory patterns, control of syntax, and conventions in lexical choice. Learners of a language, however, traverse very individual, and often unstable, trajectories toward spoken competence. While ASR systems can often handle highly proficient non-native speech with little or no modification of their statistical models, recognition performance can be very poor as proficiency levels and speaker fluency fall. Interest in handling foreign-accented speech in ASR has emerged from two different directions: large-scale applications such as dictation and telephony systems, and educational applications offering tutoring and diagnostics. Developers of the former have seen the need for adaptation to non-native speech as their systems become more widely deployed in the real world. And, as speech technology has improved, it is seen as a potentially viable tool in foreign-language education. This presentation will highlight approaches to and advances in treatment of non-native speech in ASR for these two domains, examining both characteristics of learner speech and methods for improving recognizer performance.
Dynamics of bullfrog choruses studied by time-delay localization with an acoustic array
Authors: Simmons James A. , Simmons Andrea M.
Published: October 2013

Understanding the dynamics of bullfrog choruses, particularly the occurrence of acoustic interactions among the calling males, requires segregating and characterizing the sequences of vocalizations from individual frogs making up the chorus night after night for a calling season lasting almost a month. Chorusing takes place in the dark, often at ponds surrounded by vegetation, in conditions where visual observation to locate calling individuals is rarely possible. To record choruses, we used two acoustic sensor units, each consisting of four electret condenser microphones mounted on the faces of a 3-cm cube, located 5–10 m apart and aligned alongside a pond. Signals were stored on an 8-channel digital instrumentation recorder. These signals were used to estimate the horizontal directions and, from these, the locations of multiple bullfrogs (Rana catesbeiana) vocalizing at night. The array’s mixture of short and long apertures was conceived for acoustic surveying to avoid problems caused by variations in acoustic propagation due to wind and vegetation, and to avoid ambiguities caused by multiple overlapping signals detected only over long apertures. Several kinds of acoustic interactions are evident when calls are assigned to individual animals. [Work supported by DARPA, ONR, NIH.]
Location and range of calling blue and fin whales off the Western Antarctic Peninsula
Authors: \uSirović Ana , Hildebrand John A. , Wiggins Sean M. , McDonald Mark A. , Moore Sue E. , Thiele Deborah
Published: October 2013

Blue and fin whales were heavily whaled from the Southern Ocean during the 20th century and their populations today remain at extremely low levels. Both species produce loud, low-frequency calls that are well suited for long propagation. Eight acoustic recording packages (ARPs) were deployed off the Western Antarctic Peninsula, with instrument spacing from 100 to 180 km. Blue and fin whale calls were commonly heard and two different methods were used to determine locations and ranges to the calling whales. Blue whales were localized using the differences in call arrival times to three different instruments. It also was possible to calculate ranges to blue whales from multipath arrivals of their calls and verify the results obtained by the difference in arrival times method. Short detection ranges for fin whales precluded localization, but multipath arrival difference allowed range estimation. Source levels for both species were calculated using these ranges and the measured received levels.
Acoustical design of Kumamoto Health Science University
Authors: Ikeda Masahiro
Published: October 2013

Kumamoto Health Science University was built in 2002. The key of the project is how to include variety of facilities required for medical school within a limited cost. For this purpose, a large flat circle formed with folded metal plate was adopted. The circle roof covers the rooms, which is located on the ground, except a gymnasium. The prior acoustical concern was the noise caused by rain drops on the metal roof. Through two times experiments carried out in a design and a construction stage, three types of the details were utilized depending on the purposes of the rooms. The effect of inserted rubber, which is cost effective compared to laminated damping steel sheets, is 10 dB in the structure borne transmission loss. Regarding to the room acoustics, the ceilings of lecture rooms are designed to reflect frontal reflection from talkers effectively to the seating area. Acoustical panels are located at a higher wall part instead of the ceiling. Geometrical simulation showed the effect of the acoustical design. The interior of the gymnasium was acoustically designed for utilization of ceremony and assembly, while keeping a liveness suitable for a sports utilization. The highly designed campus was realized in low cost.
Speech intelligibility in real and virtual classrooms
Authors: Yang Wonyoung , Hodgson Murray
Published: October 2013

In current research by the authors, auralization is being used to identify the optimal reverberation times and signal-to-noise level differences for speech in classrooms. The work presented here was initiated to validate the auralization procedure in comparison with live listening tests in real classrooms. Reverberation and noise conditions were created in both real and virtual classrooms, and speech intelligibility tests performed. Two architecturally identical classrooms which have different amounts of sound absorption were selected for real classroom speech intelligibility tests, and their acoustical parameters were measured. Speech and noise sources were placed at the fronts and backs of the classrooms. Speech intelligibility tests were performed at three positions with normal-hearing subjects. The modified rhyme test (MRT) and the noise babble were generated by loudspeakers. The classrooms and speech intelligibility test conditions were then simulated for auralization using CATT-Acoustics, based on the real classroom measurement results. Virtual speech intelligibility tests were performed on the same subjects in the laboratory using headphones. The MRT results in the real and virtual classrooms were compared.
Insights into underwater behavior and vocalizations of blue and fin whales from attachments of acoustic recording tags
Authors: Calambokidis John , Oleson Erin M. , Burgess William C. , McDonald Mark A. , Hildebrand John A.
Published: October 2013

The underwater behavior and vocalizations of blue and fin whales in the northeast Pacific were examined using three types of electronic archival tags attached with suction cups. The bulk of the attachments were of the ‘‘Bioacoustic Probe,’’ a commercially available acoustic recording tag developed by Greeneridge Sciences under ONR support. We completed more than 30 deployments of this tag between 2002 and 2004 at multiple locations off California and in the Sea of Cortez, Mexico. Acoustic data recorded by the tags were used to investigate: (1) vocalizations made by the tagged subject whale and nearby animals; (2) anthropogenic noise to which the subject was exposed, including airguns and vessel noise; and (3) the variability of flow noise, which indicated the relative speed of the subject through the water. Results to date have revealed a number of new findings on blue whale vocalizations, including that only a small proportion of blue whales are producing regular calls, that more blue whales may be producing calls irregularly than regularly, and that callers are males. The new data have also clarified the behavioral context in which calling takes place. [Work supported by ONR, SERDP, CNO N45.]
Acousto–photonic imaging: Modulation of light by ultrasound for medical imaging
Authors: DiMarzio Charles
Published: October 2013

Dual-wave technologies hold the promise of new medical imaging techniques. One such combination is acousto–photonic imaging, in which light waves are ‘‘tagged’’ by ultrasound waves. The promise is the spectroscopic capability of optical imaging, to measure hemoglobin, with the resolution of ultrasound. A further promise is the ability to measure both optical and acoustic properties in a single measurement. The mechanisms of interaction include modulation of the optical index of refraction and modulation of the distance between optical scatterers, both resulting in phase shifts of the detected light. Because these phase shifts are random, they are difficult to detect. Detectors average over many speckles and thus do not enhance the signals. The use of a photo-refractive crystal permits large detectors to be used, and also provides resolution in the axial direction, leading to the possibility of using the ultrasound to introduce virtual sources of diffusive waves, which can be treated with processing techniques employed in diffusive optical tomography. This talk will provide an overview of the field, including various source and detector configurations, measurement techniques, and suggestions for practical implementation.
Schlieren imaging of sound at the turn of the century
Authors: Zanelli Claudio I. , Howard Sam M.
Published: October 2013

The mystery of sound fields lies largely in that, despite the complex presence of diffraction effects, at a human scale, they cannot be seen. We sample an acoustic field two points at a time, and mapping it completely, even in two dimensions, requires a constant field and a lot of patience. Vision allows capturing two-dimensional images, and even mental three-dimensional images. Yet light can only be seen when it is interfered with, and scattered into, our retinas. Like sound, we must destroy its field in order to sense it. Quite possibly, the lack of sensory perception of acoustic field maps is responsible for our slowness in understanding the nature of waves. The limitations of point-to-point mapping of fields leads many to take a few samples and then work directly with mathematical models. Schlieren is an ancient yet rediscovered, fascinating technique to generate instantaneous maps of acoustic fields based on the interaction of light and sound. Its value as a guide to intuitively connect with the underlying physics is undeniable, and new developments have turned it into a quantitative method, even where no other mapping methods are possible.
Combining acousto-optical imaging with diagnostic ultrasound: resolution, contrast and speed
Authors: Bossy Emmanuel , Sui Lei , Murray Todd W. , Roy Ronald A.
Published: October 2013

Ultrasound modulation of light can be used to image optical properties in highly diffusive media such as biological tissues. In a previous study [Bossy et al., J. Acoust. Soc. Am. 115, 2523 (2004)], a commercial ultrasound scanner was combined with a photorefractive crystal (PRC)-based optical detection scheme to generate simultaneous images of acoustic and optical properties of inclusions embedded in diffusive tissue phantoms. In this paper, we quantitatively investigate the performance of the system in terms of resolution, contrast, and acquisition time. Measurements are performed on gel-based highly diffusive tissue phantoms, with embedded targets possessing optical contrast relative to the surrounding medium. The resolution of the acousto-optical images turns out to be given by the ultrasound beamwidth for the lateral resolution, and by the pulse duration for the axial resolution. Phantoms and targets with different optical contrasts are imaged to assess the feasibility using this technique to delineate tissue types in vivo. The time needed to acquire acousto-optical images depends on the desired quality of the image (signal-to-noise ratio) and ranges from 1 to 30 s per line. [Work supported by the Center for Subsurface Sensing and Imaging Systems via NSF ERC Award Number EEC-9986821.]
Design and performance of a micro-probe microphone
Authors: Daigle Gilles A. , Stinson Michael R.
Published: October 2013

It is often necessary to measure sound fields in confined spaces where minimum disturbance of the sound field is important. The B&K 4170 is a horn-coupled probe microphone for which a 1.25-mm-i.d. probe is attached to the narrow end of the horn and a 1/2-inch microphone is connected to the wide end. In applications where the confinement of the space is extreme, this probe is too large. The probe section of the B&K 4170 has been redesigned using smaller diameter probes. Simulations were made for probes having outside diameters ranging from 1.25 mm down to 0.2 mm. It was found that acceptable sensitivities could be expected from a probe with 0.2 mm o.d. (0.1 mm i.d.) if the length is less than 1 cm. The micro-probe is connected to a larger cylindrical tube with the correct o.d. for mounting on the B&K 4170 casing. Viscous resistance due to the small diameter provides an almost flat response. Several micro-probes were constructed and their performance measured and compared to the simulated results.
Harsh environment windscreen analysis and design
Authors: Hill Jeffrey , Blotter Jonathon , Leishman Timothy
Published: October 2013

This paper presents the analysis and design for a multimicrophone probe placed outdoors in relatively harsh environments including high temperature, high humidity, rain, wind, and soil particles. The windscreen was designed to minimize the insertion loss as well as maintain the phase relationship in a circular 5-probe microphone array. A numerical CFD model, which accounts for wind, soil particles, the windscreen material, and transient pressure fluctuations, will be presented. The parametric design using this numerical model will be presented and discussed, along with experimental results. The experimental testing consists of measuring the wind attenuation, the insertion loss, as well as any errors in the phase relationship. Testing is done in an anechoic chamber using two methods: a stationary microphone array, and attaching the microphone system to a rotating arm to simulate the wind. Measurement results which correlate the density and thickness of the foam with the insertion loss and the drop in wind noise level caused by the foam will be presented. Also, the insertion loss due to different weather-proof coverings is reported.
Investigation on tonal and playability qualities of didgeridoos: Correlations with physical properties
Authors: Causse Rene E.
Published: October 2013

The quality of an instrument, perceived by a player, is usually separated into two fields, tonal and given possibilities by the instrument in terms of playability. For the didgeridoo, tonal quality is first linked to the spectral content of the emitted notes, a result of the oscillation of a complex system composed of the instrument, the lips and the player’s vocal tract. Is also related to the character of spatialization of the sounds which one sometimes associates with the semantic attribute of sound width or sound envelopment. The playability is attached to the playing facility but also to the various aptitudes of the instrument. Among those one finds the aptitude for the modulations, for the rhythmic effects, for the overblowing, for vocalization, the cries, etc. The air column resistance, the sound efficiency, and the sound dynamics are also linked to the playability. The study is carried out on a series of eight instruments chosen in a corpus of around 50 instruments. The study includes tests with instrumentalits, acoustical and geometrical measurements and analysis of the emitted sounds. Some correlations between the physical properties of the same instrument, the nature of the emitted spectrum and the quality will be presented.
Additional modes in transients of a Balinese Gender dasa plate
Authors: Rolf Bader
Published: October 2013

The initial transient of a Balinese bronze plate of a Gender dasa (metallophone) struck by the instrument’s hammer is examined in detail. The spectrum of the radiated sound as well as that of measurements by an accelerator consist of many more eigenmodes compared to the theoretical values for the bending, longitudinal, axial and torsional wave modes. It shows up that the trapezoid shape of the plate leads to these additional frequencies in the transient spectrum, which disappear in the quasi-steady state. As to each bending mode, there exist at least two additional modes. There seems to be a scattering of the initial impulse at the geometrically unsteady boundaries of the trapezoid, which define new internal borders, where new modes can arise from. The low energy of these modes results in a fast decay, while the fundamental mode is still sustained by the bamboo resonator of the Gender. Computer models show the reasoning for such additional spectra modes in principle using transient impulse simulations. These modes can occur just in the case of a hard struck as the typical playing mode of Bali music, which is known to be more lively than Japanese music and corresponds to the initial transient found here.
Place of articulation effects on the acoustic correlates of the stop voicing distinction in French
Authors: Abdelli-Beruh Nassima
Published: October 2013

This study examined the influence of place of articulation on some acoustic correlates of the voicing distinction in syllable-initial (VOT, closure duration and closure voicing) and in syllable final stops (preceding vowel duration, closure duration, closure voicing and release) embedded in different French sentence contexts (between vowels, between voiceless-fricatives). Results indicated that, as in English, VOT increases as place of articulation moves back in the mouth, labial closures are longer than alveolar and velar closures and preceding vowel durations are shorter before alveolars than before labials and velars. Finally, /b/’s are significantly more often phonated than /d/’s or /g/’s in the between voiceless-fricatives context only. The effects of place of articulation on closure and preceding vowel durations are mediated by the factors of voicing category, local phonetic context and syllable-position.
Greek fricatives: Inferring articulation from F2 at vowel onset
Authors: Lee Chao-Yang , Malandraki Georgia
Published: October 2013

Fricative consonants are produced with a narrow constriction in the vocal tract. According to the acoustic theory of speech production (Fant, 1960), fricatives are characterized by spectral prominences corresponding to the natural frequencies of the cavity anterior to the constriction. The spectral characteristics may also be modified by acoustic coupling of the noise source to the cavity behind the constriction (Stevens, 1998). In addition to the defining acoustic attributes, other articulatory gestures may be added to enhance the perceptual saliency of the fricatives (Stevens, 1989). This study examines the second formant frequency (F2) at the onset of a vowel following a fricative as an indication of tongue body position, a potential enhancing gesture for fricatives. F2 measurements were obtained from a database of 1950 tokens including all ten Greek fricatives (five places of articulation, two voicing categories) produced in five vowel contexts by 25 speakers. The results indicate highest F2 for palatals, followed by alveolars, dentals, labiodentals, and velars. Despite some variability by vowel context, the F2 values are reliably distinct among the five places of articulation. These findings are discussed in terms of the acoustic theory and the enhancement account.
An ultrasound and tagged cine MRI study of German vowels
Authors: Pouplier Marianne , Buchwald Adam , Stone Maureen
Published: October 2013

German vowels contrast along the tense–lax as well as the rounding dimension, rendering a relatively complex (front) vowel system. The difference between tense and lax vowels is often described in terms of more extreme articulator movement and greater muscular tension for tense vowels, manifest especially in tongue root displacement and tongue height. These factors are assumed to correlate in the Germanic languages. This study uses ultrasound data to investigate global tongue shape and in particular tongue root differences for German monophthongs in stressed position. Preliminary results for one speaker indicate that some vowel pairs are nearly identical in tongue height, but differ in tongue root displacement. Rounded front vowels are more retracted and lower than their unrounded counterparts. The /a: a/ pair, which has been described as contrasting in duration only, exhibits a clear qualitative difference as well. In addition, tagged cine MRI data were collected for a subset of high and mid vowels. This technique allows inferring expansion and contraction of the tongue musculature and thus can inform about differences in muscular tension between tense and lax vowels. [Supported by NIH Grant RO1-DC01758.]
A formant-to-area conversion technique based on acoustic sensitivity functions
Authors: Story Brad
Published: October 2013

A technique for transforming formant frequencies to vocal tract area functions is developed by using sum and difference combinations of acoustic sensitivity functions to perturb an initial vocal tract configuration. First, sensitivity functions [e.g., Fant and Pauli, Proc. Speech Comm. Sem., Vol. 74 (1975)] are calculated for a neutral area function, at its specific formant frequencies. The sensitivity functions are then multiplied by scaling coefficients that are determined from the difference between a desired set of formant frequencies and those supported by the current area function. Then, the scaled sensitivity functions are summed together to generate a perturbation of the area function. This produces a new area function whose associated formant frequencies are closer to the desired values than the previous one. This process is repeated iteratively until the coefficients are equal to zero or are below a threshold value. Results show that vowel area functions are generated that are comparable to those measured with imaging techniques. The performance of the technique with time-varying formant frequencies will also be discussed. [Work supported by NIH R01-DC04789.]
Abyssal monitoring of upper ocean processes
Authors: Munk Walter H. , Dzieciuch Matthew A. , Worcester Peter F.
Published: October 2013

The transition from the early surface-reflected to near-surface-refracted waves is associated with a triplication pattern of arrivals which is very sensitive to upper ocean processes, including mixed layer formation, spicy fronts and internal waves. The pattern is well sampled at surface-conjugate depths (3 to 5 km). Deep and relatively short vertical arrays operating in the still, uniform abyssal environment are an attractive alternative to shallow in situ measurements.
Prescription frequency-modulated signal design for the long-range ocean acoustic propagation experiment (LOAPEX)
Authors: Andrew Rex K. , Mercer James A. , Howe Bruce M.
Published: October 2013

A ‘‘prescription frequency-modulated’’ signal is a swept FM signal whose sweep rate and possibly envelope are adjusted according to some a priori prescription. An idea advanced by Birdsall and Metzger in 1994 for the ATOC long-range tomography experiment, the concept is being revisited for LOAPEX as an alternative to ‘‘m-sequences.’’ The prescription can be used to tailor the output spectrum to a preferred shape: the sweep rate is slower at frequencies where more spectral energy is needed, and faster where less is needed. The prescription can also compensate for the transducer response. In addition, the prescription can drive the envelope to predefined maximum levels at every frequency, producing a signal which is ‘‘optimal’’ with respect to drive level. This signal is in general far less stressful on transducers than standard m-sequences. Examples of prescription FMs used during the LOAPEX experiment will be presented. [Work supported by ONR.]
The long-range ocean acoustic propagation experiment (LOAPEX) observable: Modal content as a function of arrival time. Part A: Relevance
Authors: Henyey Frank S. , Wolfson Michael A.
Published: October 2013

It is well known that for gradual enough changes in the sound speed structure, the mode number is nearly constant. Thus, changes in mode number are the most direct measure of scattering by smaller structures, such as internal waves. The mode number changes can be determined from data by separating the signal by arrival time. It is shown how the separation happens in an ideal case without scattering, allowing an optimum choice of the time window. The modal content in a small time window can also be estimated from the depth dependence of the intensity in the region of the turning depths of the modes. Each mode has a rapid falloff near its turning depth, and the extension beyond that depth measures the higher mode content. The deep vertical line array at LOAPEX measured this depth dependence. In addition, for certain times, all of the arrival is in the deep array, allowing unambiguous projections onto modes, especially if the source is above the sound axis. [Work supported by the Office of Naval Research.]
Natural and urban soundscapes: The need for multi-disciplined research
Authors: Kull Robert , Schulte-Fortkamp Brigitte , Rossberg Sebastian
Published: October 2013

Characterizing soundscapes represents a broad variety of approaches (ecological, sociological, phenomenological) in a continuum from completely natural to highly urban environments. There is an urgent need for the use of innovative designs which integrate the different levels of current analyses (qualitative and quantitative; individual and aggregate levels). The criteria (beyond sound level) of a good soundscape (What is a sensitive soundscape? What are soundscape requirements for a resort area or natural quiet?), that should be protected are central to the origin of the soundscape idea. Other classical acoustics questions, such as the use of audibility intrusiveness under critical conditions and under condition of mixed sources and time pattern, should be asked differently to deepen insight and understanding. A first attempt was made to monitor acoustical changes in an Italian mountain resort: Classical indicators (L95, L5, Leq) were used to locate geographical areas of increases in intrusiveness of the soundscape and linked to the activity pattern of the area. Several projects were conducted to define and localize quiet areas for a nature conservation program. Descriptive and analytical techniques, such as participatory sound and listening walks, cognitive maps, acoustical spectrographic maps, and soundscapegraphy are new techniques to consider for multi-disciplined approaches in different environments.
On the temporal scope of boundary effects in articulation
Authors: Byrd Dani , Krivokapic Jelena , Lee Sungbok
Published: October 2013

Boundary-adjacent acoustic lengthening is well explored, and the articulatory bases for this lengthening are becoming better understood. However, the temporal scope of boundary effects has not been examined in the articulatory domain. The few acoustic studies examining the distribution of lengthening indicate that boundary effects extend from one to three syllables leftward from the boundary, and that effects diminish as distance from the boundary decreases (Cambier-Langeveld, 1997; Shattuck-Hufnagel and Turk, 1998; Turk, 1999; Berkovits 1993a,b, 1994). This diminishment is predicted by the pi-gesture model of prosodic influence (Byrd and Saltzman, 2003). We present an experiment testing the leftward and rightward scope of articulatory lengthening. One condition (CV♯C1VC2VC3V) tested the scope of effects after the boundary, and another (C3VC2VC1V♯CV) the scope preceding the boundary (where ♯ indicates an intonational phrase boundary) as compared to a no-boundary control. Movement-tracking (EMA) data allowed the evaluation of constriction formation and release duration, acceleration, and spatial magnitude. Further, FDA (functional data analysis) was used to examine continuous temporal warping properties. Results of both analyses indicate an asymmetrical distribution of boundary effects, in that leftward effects are shorter in scope than rightward effects, though effects in both directions exist around a phrase boundary. [Work supported by NIH.]
Towards standard measures of articulatory timing
Authors: Oliveira Leonardo , Yanagawa Mariko , Goldstein Louis , Chitoran Ioana
Published: October 2013

Many studies have investigated the relative timing (or overlap or latency) between articulatory events to make inferences about coordination in speech production or about phonetic structure. A major problem is that these studies employ different measures of relative timing. One criterion for choosing a standard measure could be the variability exhibited across repetitions and talkers for a given set of gestures in a given phonological context. If a single measure appears to be the least variable across a variety of experiments, then it is a good index of the stable, phonetically relevant properties of coordination. In this study, 33 measures were compared using coefficient of variation. In four corpora of articulatory data on consonant clusters (EMMA and x-ray microbeam), three articulatory events were defined: gesture onset, target, and release. Based on these events, coefficients of variation for the 33 measures were calculated across repetitions and speakers under a number of different linguistic conditions, i.e., stress, syllable, rate, cluster type and language (English and Georgian). Despite the very different properties of the corpora, the least-variable measures were always very similar and involve normalizing the latency between the two gestures by the constriction formation time (target to onset). [Work supported by NIH.]
Optical phonetics and visual perception of lexical and phrasal boundaries in English
Authors: Auer Edward T. , Kim Sahyang , Keating Patricia , Scarborough Rebecca A. , Alwaan Abeer , Bernstein Lynne E.
Published: October 2013

Detection of lexical and phrasal boundaries in the speech signal is crucial to successful comprehension. Several suprasegmental acoustic cues have been identified for boundary detection in speech (e.g., stress pattern, duration, and pitch). However, the corresponding optical cues have not been described in detail, and it is not known to which optical cues to boundaries speechreaders are attuned. In a production study, three male American English talkers spoke two repetitions each of eight pairs of sentences in two boundary conditions (one-word versus two-word sequences, one-phrase versus two-phrase sequences). Sentence pairs were constructed such that they differed minimally in the presence of a boundary. Audio, video, and 3D-movements of the face were recorded. Sentence pairs in both boundary conditions differed on both optical and acoustic duration measurements. A subset of the sentence pairs was also presented in a visual perception study. Pairs were chosen a priori because they differed or did not differ on the production measures. Fourteen perceivers detected boundary presence from video-alone in a forced-choice paradigm. Both lexical and phrase boundaries were reliably detectable by perceivers. The relation of visual intelligibility to the optical characteristics of production will be discussed. [Research supported by NSF IIS 9996088 and NIH DC04856.]
Comparing rhythm and melody in speech and music: The case of English and French
Authors: Patel Aniruddh D. , Iversen John R. , Rosenberg Jason C.
Published: October 2013

Does the prosody of a nation’s language leave an imprint on its music? We address this question by comparing British English and French, a stress-timed vs syllable-timed language with salient intonational differences. We previously showed that an empirical difference between speech rhythm in the two cultures is reflected in instrumental music. In this study we expand on these rhythmic measurements and provide new data on melody. We compare English and French intonation using a measure which can also be applied to musical melodies. In a database of read speech we converted the intonation contour of each sentence into a sequence of vowel pitches, using the mean fundamental frequency of each vowel to represent its pitch. We found that the size of pitch intervals between successive vowels varied more in British English than in French speech. We then examined classical instrumental music and found that pitch intervals between successive notes varied more in English than in French music. We also examined differences in the way rhythm and melody are aligned in both speech and music. Overall, we find that the prosody of a culture’s language is reflected in the structure of its instrumental music. [Supported by Neurosciences Research Foundation.]
Multi-array passive search in a littoral environment
Authors: DelBalzo Donald R. , Rike Erik R. , McNeal David N.
Published: October 2013

Acoustic barrier tactics were developed during the Cold War for deep, uniform underwater environments. Oceanographic and acoustic conditions in littoral environments are extremely complex and dynamic. The spatial and temporal variability of low-frequency signal and noise fields in these complex environments destroys the basic homogeneous assumption associated with standard tactical search concepts. Genetic algorithms (GAs) have been applied to both the signal and noise parts of this problem to produce near-optimal, nonstandard search tracks that maximize probability of detection in such inhomogeneous noise fields. In the present work, a GA was used to optimize tactics of several passive searchers by constructing optimal barriers in complex, littoral environments. The dynamic ambient noise model (DANM) was used to produce realistic, low-frequency, directional noise fields, based on discrete ship tracks. The cost function to be minimized was the probability that a target crossed the barrier undetected. Both standard and GA-derived tactics were evaluated and compared. The results show the importance of nonstandard tactics and careful consideration of environmental complexity when designing optimal passive search tactics. [Work sponsored by NAVSEA under the LCS project.]
Beamformer waveguide invariant source localization on the New Jersey shelf (USA) during winter acoustic propagation conditions—RAGS03
Authors: Turgut Altan , Pasewark Bruce H. , Orr Marshall H. , Rouseff Daniel
Published: October 2013

Horizontal and vertical beamformer (waveguide) invariants are used to robustly localize broadband noise sources (ships) using signals in the 50–200-Hz band. The localization is realized by using signatures recorded on one horizontal and three vertical arrays. In brief, waveguide invariant theory applied to beamforming by two vertical arrays provides a range ratio of the source to the receivers. Beamforming by a horizontal array provides time-evolving spectrum for a particular look direction (LOFARgram). As a result the trajectories of the striations observed in LOFARgrams can be used to estimate the speed, range and direction of a broadband source. In December 2003 the Naval Research Laboratory moored three vertical arrays and one horizontal array at ranges of 10, 20 and 30 km from two fixed acoustic sources on the New Jersey (USA) shelf. Acoustic signatures from passing merchant and research vessels were recorded on the arrays and used to demonstrate source localization. [Work supported by ONR.]
Optimal sensor placement in highly variable acoustic fields to increase detection
Authors: Rike Erik R. , DelBalzo Donald R.
Published: October 2013

Optimal placement of sensors for detection depends on spatial and temporal properties of ambient noise (AN) and transmission loss (TL). These acoustic quantities are highly variable in littoral environments and their predictions are often overly smoothed when estimating detection probabilities. This variability was characterized using the dynamic ambient noise model (DANM) and the parabolic equation (PE) model. DANM was used to produce space and time estimates of directional noise based on discrete ship tracks and the PE was used to characterize spatial variability in TL. Then, Brown’s algorithm for search planning was modified to include realistic ordered search against diffuse target distributions and used to determine the relative importance of non-homogeneous noise statistics and TL in optimizing search tactics. The new capability is COBRA (coherent optimization for Baysean resource allocation), which is efficient and accurate. The results in one littoral area show that spatial variations in TL are twice as important as those in AN for optimal search planning. This work has immediate application to design of optimal sonobuoy field patterns and future application to mobile sonar search planning. [This work was sponsored by ONR under the LADC project.]
Horizontal array gain variability measured on the New Jersey shelf during late fall and early winter propagation conditions—RAGS03
Authors: Pasewark Bruce H. , Turgut Altan , Orr Marshall H. , Schindall Jeffery A. , McCord Michael , Carey Earl
Published: October 2013

A conventional beamformer has been applied to 300 Hz CW and 300 Hz center frequency LFM acoustic signals received on a 96-channel 465 m bottomed horizontal array. The temporal history of the array gain for five subapertures (30, 60, 120, 240, 465 m) will be presented. The gain of each subaperture varied over time scales ranging from less than 1 min to 13 days. The time dependence is being correlated to sound speed variability induced by shelf slope front movement, the internal tide, nonlinear internal waves and atmospheric forcing. The longer apertures did not achieve ideal array gain. Temporal variability of the horizontal spatial coherence lengths will be discussed. The acoustic sources were moored 18 m above the bottom in 64 m of water. The propagation path was cross shelf. The receiving array was located near the New Jersey (USA) shelf break 20 km from the source. Water depth at the array location was 89 m. [Work supported by ONR.]
Noise characterization at the international station of Crozet Islands (H04)
Authors: Roueff Antoine , Piserchia Pierre-Franck , Plantet Jean-Louis , Cansi Yves , Ruzie Gerard
Published: October 2013

In the context of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), the hydroacoustic network gives the ability to state parties to check the natural and artificial activity in the oceans. To achieve this purpose, 11 hydroacoustic stations are going to be established. One of these stations has recently been launched by the CEA (France) near the Crozet Islands in the Indian Ocean. In this paper, we characterize the ambient noise of this new station. This study will enable one to estimate the detectability of the station. In this analysis, we associate the tide height with the noise level on the recorded signals. The lunar calendar perfectly matches the hydroacoustic noise variation. In addition, we will show the influence of this noise evolution on the rate of detection. In order to have a good statistic, we process a hundred days of data (recorded at 250 Hz). The tide heights supplied by ‘‘le Laboratoire de gophysique et Ocanographique de Toulouse,’’ are sampled with a 1-h step. Furthermore, the spectral characteristic of the ambient noise is also given. Finally, a comparison with other international stations, Diego Garcia (H08) and Cape Leeuwin (H01), is given.
Ultrasound-aided high-resolution biophotonic imaging
Authors: Wang Lihong V.
Published: October 2013

Using non-ionizing electromagnetic and ultrasonic waves, we develop novel biophotonic imaging for early-cancer detection, a grand challenge in cancer research. Unlike ionizing x-ray, non-ionizing electromagnetic waves such as optical waves are safe for biomedical applications and reveal new contrast mechanisms and functional information. For example, our spectroscopic oblique-incidence reflectometry can detect skin cancers based on functional hemoglobin parameters and cell nuclear size accurately. Unfortunately, electromagnetic waves in the non-ionizing spectral region do not penetrate biological tissue in straight paths as x rays do. Consequently, high-resolution tomography based on non-ionizing electromagnetic waves alone is limited to superficial tissue imaging as demonstrated by confocal, two-photon, and optical-coherence microscopic technologies. Ultrasonic imaging, on the contrary, furnishes good imaging resolution but has poor contrast in early-stage tumors and in addition has strong speckle artifacts. We developed ultrasound-mediated imaging modalities by combining electromagnetic and ultrasonic waves synergistically. The hybrid modalities yield speckle-free electromagnetic-contrast at ultrasonic resolution in relatively large biological tissue, where the spatial resolution is scalable with the ultrasonic frequency. In ultrasound-modulated optical tomography, a focused ultrasonic wave encodes diffuse laser light in scattering biological tissue. In photo-acoustic (thermo-acoustic) tomography, a low-energy laser (rf) pulse induces ultrasonic waves in biological tissue due to thermoelastic expansion.
Comparison of auditory localization performance with various loudspeaker rendering systems
Authors: Henderson Paul D. , Pieleanu Ioana N. , Way Evelyn , Torres Rendell R.
Published: October 2013

Sound-field rendering systems based on multiple loudspeakers provide significant benefits as auditory displays for many applications in virtual audio, multimedia, teleconferencing, and auralization. In contrast to headphone-based binaural reproduction, the performance of loudspeaker rendering systems is independent of the HRTFs of the listener, and the listener is physically decoupled from the rendering system. In addition, many rendering techniques such as wave-field synthesis (WFS) are capable of simultaneously presenting an accurate perceptual experience to multiple listeners. However, the sound-field rendering technique, loudspeaker configuration, and number of sources play an important role in both the physical behavior of the rendering system and the associated localization performance of listeners. In this study, we examine the in situ localization performance of listeners exposed to various loudspeaker rendering systems using virtual sources. Specific reproduction methods investigated are WFS, first- and second-order Ambisonics (including a periphonic implementation), and stereophonic rendering techniques. In addition to virtual sources in the simulated free field, the effect of adding spatialized reverberation is also reviewed. The results are compared with a study of baseline auditory-system localization performance with real sources. [Work supported by the National Science Foundation and Rensselaer Polytechnic Institute.]
Nonlinear acoustic experiments involving landmine detection: Connections with mesoscopic elasticity and slow dynamics in geomaterials
Authors: Korman Murray S. , Fenneman Douglas J. , Sabatier James M.
Published: October 2013

The vibration interaction between the top-plate of a buried VS 1.6 plastic, anti-tank landmine and the soil above it appears to exhibit similar characteristics to the nonlinear mesoscopic/nanoscale effects that are observed in geomaterials like rocks or granular materials. In nonlinear detection schemes, airborne sound at two primary frequencies f1 and f2 (chosen several Hz apart on either side of resonance) undergo acoustic-to-seismic coupling. Interactions with the compliant mine and soil generate combination frequencies that, through scattering, can effect the vibration velocity at the surface. Profiles at f1, f2, f1−(f2−f1) and f2+(f2−f1) exhibit a single peak while profiles at 2f1−(f2−f1), f1+f2 and 2f2+(f2−f1) are attributed to higher order mode shapes. Near resonance (∼125 Hz for a mine buried 3.6 cm deep), the bending (softening) of a family of increasing amplitude tuning curves (involving the surface vibration over the landmine) exhibits a linear relationship between the peak particle velocity and corresponding frequency. Subsequent decreasing amplitude tuning curves exhibit hysteresis effects. Slow dynamics explains the amplitude difference in tuning curves for first sweeping upward and then downward through resonance, provided the soil modulus drops after periods of high strain. [Work supported by U.S. Army RDECOM, CERDEC, NVESD, Fort Belvoir, VA.]
Coupled mode theory for sound propagation through random internal wave fields
Authors: Colosi John
Published: October 2013

In the late 1970’s Dozier and Tappert were able to formulate a theory for the range evolution of deep-water acoustic normal-mode energies utilizing (1) a perturbation method up to second-order mode transitions; (2) a phase-randomized internal wave field; (3) the Markov approximation; and (4) zero cross-mode coherence. Since 1989, vertical receiver array observations of broadband signals at 75 and 250 Hz have shown distinct time-resolved wavefronts at multimegameter ranges, thereby invalidating the zero cross-mode coherence assumption. In this work, the theory is modified to remove the zero cross-mode coherence assumption, thereby yielding range evolution equations for both the mode energies and the cross-mode coherences. Using a Lorentzian internal wave spectrum which fits the Garrett–Munk spectrum very well, analytic expressions for the coefficients of the evolution equations are obtained. Predictions using the theory agree with Monte Carlo numerical simulations at 75 Hz at roughly the 1–2-dB level. It is found that cross-mode coherences decay very slowly with range, and that the modal energy equations nearly decouple from the cross-mode coherence equations. The theory may offer a means to acoustically measure internal wave spectra.