bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the resonance frequency shift in parts with cracks
Authors: Zahariev Krasimir , Kin Yulian , Sutin Alexander
Published: October 2013

It is known that development of crack in various parts leads to resonance frequency variation and that phenomena can be used for crack detection and remaining lifetime prediction. We have investigated this effect on a steel specimen (25×150×6 mm). The crack was initiated at the root of preliminary machined notch and propagated under cycling loading on fatigue machine. The finite-element analysis was applied for calculation of frequency shift for three flexural modes of vibration and it was observed that the frequency shift increases with the increase of crack size. The maximum detected frequency shift was 3.8% for the crack size 23% of a sample width. The experimental measurements were conducted by measurements of sound produced by free vibration of the sample after impact excitation (impact resonance acoustic spectroscopy). The relative difference between acoustical measurements and FEA results did not exceed 1%. The conducted research provides a good basis for development of the remaining life prediction methods, for example, by Paris formulation. Parameters of the formulation for our case were determined experimentally. [Research supported by 21 Century Fund of Indiana.]
Effects of material anisotropy on the amplitudes of waves in cylindrical structures
Authors: McDaniel J. Gregory
Published: October 2013

Composite materials may be designed and configured to substantially alter the generation and propagation of elastic waves with a relatively small weight penalty. The anisotropy introduced by composite structures leads one to intuitively expect that wave amplitudes will depend strongly on the orientations of the applied force as well as the composite material. The present work investigates this effect for cylindrical structures with point forces. Using a mixture of analytic and numerical models, an understanding of the relationship between force directivity, material orientation, and wave amplitudes is developed. Results of this study lead directly to design strategies for controlling power flow to the structure. [Work supported by ONR.]
Tri-axial hybrid (passive-active) vibration isolator using single crystal piezoelectric actuators
Authors: Herdic Peter , Corsaro Robert , Houston Brian , Baden Robert
Published: October 2013

Results are presented for a laboratory study of a tri-axis hybrid (active-passive) vibration isolator. A previous report [J. Acoust. Soc. Am. 112 (2002)] described control studies performed using single-axis control. It identified the optimum physical control law by examining the placement order within the device consisting of a passive compliant spring, sensing layer, and piezoelectric actuator. Additionally, actuator materials were evaluated by examining the performance levels of three piezoelectric materials having different nonlinearity values: PZT-4, PZT-5A, and PMN-PT single crystal. The study described here extends this previous work to the required, more complicated case of three-axis control. Described are the development, design, and fabrication of a hybrid device that demonstrates stable, robust, and reproducible ‘‘local’’ vibration reductions of ∼30−−45 dB simultaneously in all three excitation axes. These results are found for both single and multiple tone tri-axis disturbances and with negligible out-of-band enhancement, where the total harmonic distortion of the system is less than 0.25%. The control approach, using base acceleration minimization, demonstrates ∼35 dB of ‘‘downstream’’ performance, which is ∼25 dB higher than that of the passive element alone. The device is sufficiently small and simple to fabrication that it offers potential for being used in practical applications.
50 years of phonetics with Peter Ladefoged
Authors: Ladefoged Jenny
Published: October 2013

Ladefoged’s many different takes on phonetics, in many countries, will be described.
The influence of Peter Ladefoged
Authors: Stevens Kenneth N.
Published: October 2013

The research and publications of Peter Ladefoged and his students have been a strong influence in elevating the field of phonetics to a science, and in bringing together phonetics and phonology. I will cite some examples of how Peter’s work and that of his colleagues has influenced the research of many of us at MIT and around the world, where attempts to develop unifying theories often need to undergo continuous revision based on the meticulous articulatory and acoustic data that he reports in his books and other publications. These include his descriptions of the involvement of the tongue root in vowel systems, the fricatives of Mandarin Chinese, the inventory of places of articulation he catalogs in the languages of the world, and the many uses of laryngeal states in providing phonological contrasts. [Supported in part by grants from NIDCD.]
Nonlinear deconvolution approaches
Authors: Frieden B. Roy
Published: October 2013

A review of past methods of digital signal restoration is given. Emphasis is upon nonlinear methods, owing to their extra precision in allowing inequalities and other forms of prior knowledge to be entered as constraints. Some specific methods of this type are maximum entropy, maximum bounded entropy, maximum shannon information, recursive median window filtering, Jansson recursion, and minimum Fisher Information. Algorithms and demonstrations will be given.
Measuring, predicting, and characterizing reflections
Authors: D’Antonio Peter , Cox Trevor J.
Published: October 2013

Over the past 100 years, since the founding of architectural acoustics by Sabine, there has been considerable effort devoted to studying surface absorption. Over this period, a considerable library of absorption coefficients has been tabulated, based on accepted standards of measurement, and the role of absorptive surfaces is now well understood. In contrast, scientific knowledge about how scattering surfaces should be measured and characterized and how, where, when, and why these surfaces should be used is still evolving. Over the past three decades, how to design, optimize, predict, measure, and characterize the performance of scattering surfaces has been learned. This presentation will describe the procedures developed to measure, predict, and quantify scattering surfaces. Standardized procedures for determining scattering coefficient and correlation scattering coefficient, which indicate the amount of sound scattered away from the specular direction, and the diffusion coefficient, which indicates the uniformity of scattering, will be described and examples given. Three-dimensional balloons, which display the polar distribution of scattered sound, will also be displayed. The goal is that, as these standards become more widely understood, a growing library of coefficients will develop and soon absorption, scattering, and diffusion coefficients will all find their way into architectural acoustic specifications.
Reflections in computer modeling of rooms: Current approaches and possible extensions
Authors: Svensson U. Peter
Published: October 2013

Computer modeling of rooms is most commonly done by some calculation technique that is based on decomposing the sound field into separate reflection components. In a first step, a list of possible reflection paths is found and in a second step, an impulse response is constructed from the list of reflections. Alternatively, the list of reflections is used for generating a simpler echogram, the energy decay as function of time. A number of geometrical acoustics-based methods can handle specular reflections, diffuse reflections, edge diffraction, curved surfaces, and locally/non-locally reacting surfaces to various degrees. This presentation gives an overview of how reflections are handled in the image source method and variants of the ray-tracing methods, which are dominating today in commercial software, as well as in the radiosity method and edge diffraction methods. The use of the recently standardized scattering and diffusion coefficients of surfaces is discussed. Possibilities for combining edge diffraction, surface scattering, and impedance boundaries are demonstrated for an example surface. Finally, the number of reflection paths becomes prohibitively high when all such combinations are included as demonstrated for a simple concert hall model. [Work supported by the Acoustic Research Centre through NFR, Norway.]
The problem of frequency weighting functions and standards for birds
Authors: Dooling Robert , Brittan-Powell Elizabeth , Lauer Amanda , Dent Micheal , Noirot Isabelle
Published: October 2013

Frequency weighting functions in humans are widely used as a single-figure guess to assess noise problems and aid in making decisions with regard to noise limitations when no other data exist. However, this use of frequency weightings invariably results in a loss of precision in assessing the likelihood of a sound to produce hearing damage or sound annoyance. There is a growing interest in developing frequency weighting functions in animals presumably to assist in judging the risk of hearing damage, interference with acoustic communication, or habitat suitability. Laboratory studies reveal many parallels between humans and animals on a variety of psychoacoustic measures, such as equal loudness contours. However, differences between humans and animals on specific tests argue against using standards developed for humans to gauge the effect of noise on animals. Here we review data which show this same problem exists among birds. That is, the differences in the effects of noise among bird species can be as large as the differences between humans and birds. These results suggest that whereas frequency weighting functions and acoustic standards for a specific species might be useful, generalizing across species is likely not practical.
Frequency weighting in the feature extraction process: Effects of parameter choice on generalized perceptual linear prediction coefficients
Authors: Clemins Patrick J. , Johnson Michael T.
Published: October 2013

The generalized perceptual linear prediction (gPLP) feature extraction model incorporates information about the perceptual abilities of the species under study to generate features relevant to that species. The gPLP feature extraction model is based on the source-filter model of vocalization production and quantifies the general shape of the spectral envelope. gPLP coefficients remove excitation information for vocalizations with a low fundamental frequency, but capture harmonic information for vocalizations with a higher fundamental frequency through the use of a filter bank analysis component. Frequency warping, frequency masking, and equal loudness normalization, or frequency weighting, are some of the psychophysical phenomena modeled in the gPLP model. The effects of accounting for these phenomena in the feature extraction process are explored using perceptual spectrograms, statistical tests, and classification tasks. Experiments show that using this perceptual information can provide insights during the analysis of vocalizations and improve classification accuracies. The contribution of other feature extraction parameters including the number of cepstral coefficients and number of filters in the filter bank is also examined. [Work supported by the National Science Foundation under Grant No. IIS-0326395.]
Detection sensitivity of frequency modulated (FM) and constant frequency (CF) signals in temporal masking conditions in the Mongolian gerbils
Authors: Taketani Tomofumi , Sasaki Yasunari , Riquimaroux Hiroshi
Published: October 2013

The auditory systems would be sensitive to temporal changes in frequency of sounds. We hypothesized that frequency modulation would play an important role in perception. And in this study, the difference in detection sensitivity between frequency-modulated signals (FM) and constant frequency signals (CF) in temporal masking conditions was examined in three Mongolian gerbils (Meriones unguiculatus) by GO-NOGO procedure. We focused on their detection sensitivity of three types of signals; upward FM, downward FM, and CF. The frequency range of each FM was from 4 to 7 kHz, and CF was 6 kHz. We set S+ that signals were presented between white noise bursts (BW: 0 to 17.5 kHz), and then signals were temporally masked by white noise. In contrast, we set S− in which silence was presented instead of signals. Subjects were trained to detect whether signals were presented or not. After subjects reached criterion (80%), each stimulus was presented randomly and attenuated in amplitude. We investigated their response rate to each S+. Result showed that their detection sensitivity to FM was higher than that of CF. It suggests that FM is superior to CF in recognition for subjects. [Research was supported with financial assistance from MEXT.]
Listener perception of and acoustic differences between girl and boy choristers in an English cathedral choir
Authors: Howard David , Welch Graham
Published: October 2013

For centuries, boy choristers have been singing the top (treble) line in English cathedrals. Girl choristers were first admitted in 1991, and there is a long-running debate as to whether they can carry out this role appropriately. This paper will detail the results from two listening experiments designed to establish whether or not listeners can tell the difference between girl and boy choristers singing the top line in cathedral music. In the first experiment, 189 listeners took part and on average they were able to tell the difference 60% of the time; this was statistically significant over chance. The results suggested that repertoire played a significant part in this ability, and the second experiment was carried out in which the boys and girls sang the same repertoire. Nearly 170 listeners have completed this experiment and, on average, they are making guesses (correct 52% of the time). The paper will discuss the acoustic differences between the stimuli with respect to the singing of boy and girl choristers, while placing the discussion in the context of the English cathedral tradition.
Nonlinear acoustic detection of weathered, low compliance landmines
Authors: Sabatier James M. , Alberts W. C. Kirkpatrick , Korman Murray S.
Published: October 2013

Two potential impediments to acoustic landmine detection are soil weathering processes and low compliance landmines. To bury landmines, the soil within a mine diameter is removed and replaced such that bulk density, compression, and shear strength all decrease, leaving an acoustic scar detectable with the linear acoustic measurement technique. After a few soil wetting and drying cycles, this contrast is reduced. Linear acoustic mine detection measurements were made on a low impedance contrast landmine before the first rainfall on several occasions over the subsequent 5 years. During this period of time, both the spatial and frequency resolution had to be increased to maintain an on/off target velocity ratio that allowed detection. In some cases, the landmine remains undetectable. To address this, two-tone nonlinear acoustic measurements have been made on these landmines. When the landmine is detectable with linear acoustics, two tones are broadcast at the frequency where the on/off target velocity ratio is the largest. For the cases when the landmine is undetectable, a two-tone sweep is performed and the operator observes the real-time velocity FFT, noting nonlinear sidebands. Next, two-tone tests are conducted at these sidebands to determine nonlinear velocity profiles. [Work supported by U.S. Army RDECOM, NVESD.]
Effect of particle size on the vibration of plates loaded with granular material
Authors: Turner Joseph A. , Yang Liyong , Kang Wonmo
Published: October 2013

Acoustic methods of landmine detection are emerging as reliable techniques that are especially well suited for non-metallic mines. These methods rely on the vibrations of the top plate of the mine as it responds to the acoustic excitation. The plate response is complicated by the interaction with the surrounding soil. If the loading soil is granular (e.g., sand), it is expected that particle size will influence the mine response. Experimental results related to this hypothesis are presented here. The first resonant frequency of a sand-loaded plate is measured as a function of sand mass for dry sand of various sizes covering a range from hundreds of microns to a few millimeters. For low values of sand mass, the plate resonance decreases and eventually reaches a minimum. In this regime, there is no dependence on particle size. After the minimum, the frequency increases with additional mass. In this regime, a particle size effect is observed. Models are also presented to support and explain experimental results. The results are expected to impact quantitative aspects of mine detection by acoustic means. [Work supported by ARL.]
Smoothing spline analysis of variance (ANOVA) for tongue curve comparison
Authors: Davidson Lisa
Published: October 2013

Ultrasound imaging of the tongue is an increasingly common technique in speech production research. One persistent issue regarding ultrasound data is how to quantify them. Researchers often want to determine whether the tongue shape for an articulation under two different conditions (e.g., consonants in phrase-initial versus phrase-medial position) is the same or different. To address this issue, a method for comparing tongue curves using a smoothing spline ANOVA has been developed (SSANOVA) [Gu, 2002, Smoothing spline ANOVA models]. The SSANOVA is a technique for comparing curve shapes (splines) for two sets of data to determine whether there are significant differences between the curve types. Data sets contain 8–10 repetitions of each of the relevant tongue curves being compared. If the interaction term of the SSANOVA model is statistically significant, then the groups have different shapes. Since the interaction may be significant even if only a small section of the curves is different (i.e., the tongue root is the same, but the tip of one group is raised), Bayesian confidence intervals are used to determine which sections of the curves are statistically different. SSANOVAs are illustrated with some data comparing obstruents produced in word-final and word-medial coda position.
The effect of speaking rate on supersegmentals: An acoustic and perceptual analysis
Authors: Chiou Hsin-Huei , Watson Peter
Published: October 2013

Rate manipulation has been used to study change in prosodic contrasts such as emphatic stress. Timing contrasts in stressed words are reduced or eliminated when speaking rate is increased. However, reports of intonation and rate change are mixed. Some studies have reported an increase of F0 movement [M. Steppling and A. Montgomery, J. Phonetics 64, 451–461 (2002)], and other reports have found that F0 movement is decreased at faster speaking rates [C. Fougeron and S. Jun, Percept. Psychophys. 26, 45–69 (1998)]. This study examined the effect of speaking rate on F0 and duration in sentences produced with emphatic stress in different sentential position and in declarative and interrogative forms. Essentially, durational contrasts were reduced at faster speaking rates and were more pronounced at slower speaking rates. Intonation, on the other hand, was more pronounced for the fast rate and somewhat reduced for the slow rate. A perceptual component will also be reported that examines a listener’s ability to recognize stressed words and mode of sentence production (declarative and interrogative) at different speaking rates.
Production of Mandarin tone contrasts by musicians and non-musicians
Authors: Gottfried Terry L. , Ouyang Grace Yin-Hwei
Published: October 2013

Previous research has shown that native speakers of American English who are musicians perform better than non-musicians when identifying and producing the four phonemic tones of Mandarin. The present study corroborates these findings and analyzes acoustic properties of non-natives’ tonal imitations. Listeners imitated Mandarin two-syllable word phrases that varied the vowel (/li/, /la/, /lu/) and tone (high-level, mid-rising, low-dipping, high-falling) of the first syllable. Four native Mandarin speakers rated the musicians, on average, to be better in their imitation of Mandarin tone 4 (high-falling) than non-musicians. There were no significant differences between groups in how they were rated on the other three tones. Acoustical analyses revealed that non-natives failed to match native speakers both in differences in initial F0 and in F0 contour (change from initial to final F0) across tones. Imitations by musicians did not show significant acoustic differences from non-musicians, except for tone 4, where musicians’ imitations showed a significant decrease in F0 from initial to final portions of the syllable; the decrease in F0 for non-musicians was smaller and not significant. Creaky voice (often present in natives’ tone 3 and 4) was observed in many non-native imitations, but was not restricted to tones 3 and 4.
Influence of prosodic factors on segment articulations and acoustics in English
Authors: Keating Patricia , Cho Taehong
Published: October 2013

This study investigated effects of three prosodic factors—prosodic boundary, lexical stress, and accent—on articulatory and acoustic realizations of two CV syllables, /nE/ and /tE/. These syllables occurred at the beginning of trisyllabic English nonwords; their position in the larger phrase (prosodic boundary conditions), and whether they were lexically stressed and/or accented (prominence conditions) were varied. Articulatory measurements included linguopalatal contact (by electropalatography) for both C and V, stop consonant seal duration, and C-to-V contact difference; acoustic measurements include nasal duration and energy for /n/; VOT, burst energy and spectral center of gravity for /t/; and F1, vowel duration and vowel amplitude for /E/. We tested whether domain-initial strengthening occurs in the C and/or the V segments independently of stress or accent conditions. We found that the effects of position and of stress/accent can be distinguished in the production and the acoustics of these syllables. One domain-initial effect (greater consonant contact domain-initially) was complementary to one stress/accent effect (greater vowel opening with stress/accent); in other cases the effects overlapped (greater vowel energy and tendency to longer consonant both domain-initially and with stress/accent); in one case they conflicted (less consonant energy domain-initially, more consonant energy with stress/accent).
Mucosal wave velocity
Authors: Berry David A. , Zhang Zhaoyan , Neubauer Juergen
Published: October 2013

Mucosal wave velocity correlates with the elastic properties of the laryngeal mucosa, and can often discriminate normal phonation from pathology. In the past, mucosal wave velocity has been measured in the laboratory using two-point measurements. However, more recent laboratory investigations using human excised hemi-larynges have yielded quantitative vibratory data along a large portion of the medial/superior surface of the vocal fold. These data will be used to probe mucosal wave velocity as a function of (1) location on the medial and surface surfaces of the vocal fold, (2) subglottal pressure, (3) elongation force, and (4) adductory force. Such data reveal significant aspects of the mucosal wave, and the impact of this wave on phonation.
Observations of the near-field structures of the glottal flow
Authors: Neubauer Juergen , Zhang Zhaoyan , Berry David
Published: October 2013

The three-dimensional glottal jet was measured downstream from a self-oscillating physical model of the vocal folds using several techniques, including grid-based hotwire anemometry, high-speed flow visualization, and particle image velocimetry. Coherent flow structures were extracted from the spatio-temporal data using principal component analysis (PCA). The glottal jet resembled planar jets through static slitlike orifices. The direction of the jet core axis oscillated in the medial-lateral direction. Also, there was a positive correlation between the dynamics of shear layers around the laminar jet core and flow structures in the transitional region. This finding was similar to the dynamics of planar jets where jet flapping was observed previously. This can be understood in terms of an antisymmetric array of large-scale vortices being convected downstream. This antisymmetric mode of coherent vortex structures acts as an acoustic dipole that could effect the dynamics of the shear layers in the laminar core region. Thus, our observations help to understand the dynamics of the acoustic near-field of the glottal oscillator and suggest a possible feedback mechanism for source-tract coupling.
Effect of intraoral air pressure on the release of an alveolar stop closure
Authors: Chen Lan
Published: October 2013

The effect of air pressure on the release of an alveolar stop consonant closure is simulated with a 2-D finite-element model of the front part of the midsagittal tongue in the vocal tract. Active movement of the tongue is estimated from x-ray microbeam recordings, and intraoral air pressure is also applied to the surface of the tongue as an external force. Air flow in the vocal tract is then coupled to the tongue movement by representing the upper tongue surface as part of the flow boundary. At release, the upward movement of the tongue tip due to the decrease in air pressure introduces an oscillation at the release trajectory of the supraglottal constriction. This oscillation is realized in a quasiarticulatory speech synthesizer HLsyn and causes the appearance of a plateau in the time course of the output airflow. This hesitation in tongue tip movement results in an increase in the duration of the frication noise by about 10 ms, consistent with acoustic data on the stop burst. The simulation shows how the mechanical properties of the tongue and the intraoral air pressure buildup can influence the duration of the frication noise. [Supported by Grant NIDCD DC00075 from NIH.]
Identification of final fall in subglottal pressure contours of speech utterances
Authors: Hanson Helen M. , Slifka Janet , Shattuck-Hufnagel Stefanie , Kobler James B.
Published: October 2013

Subglottal pressure (Ps) contours for speech are described as having three phases: initial rise, constant or declining working phase, and final fall. The current work is part of a project to relate characteristics of the Ps contour to prosodic events. To that end, one must identify the three phases in a Ps contour. In past work, it was found that the initial phase is relatively easy to identify, but the transition from the working phase to final fall is less clear [J. Slifka (2000)]. Confounding issues could include segmental impedance, pitch accents, and phrase and boundary tones, all of which can have local effects on Ps. In this work, it is attempted to control tones and segments at the ends of utterances in order to better identify final fall. Lung pressure is estimated from esophageal pressure (corrected for lung volume). Pilot data from one subject indicate that the beginning of final fall is easier to identify when the phrase and boundary tones are low than when they are high. Results will be presented for additional subjects and it will be attempted to relate them to the distribution of pitch accents. [NIH grant DC04331.]
Blind deconvolution and source separation in acoustics
Authors: Sibul Leon H. , Roan Michael J. , Coviello Christian M.
Published: October 2013

Blind deconvolution (BDC) and blind source separation (BSS) are active research topics with many important applications in acoustics. The goal of deconvolution is to recover original input signal from the output of a convolution filter. In blind deconvolution details of the convolution filter and input signals are not known. The fundamental assumption in BDC is that the input signal is a non-Gaussian stochastic process. A topic closely related to BDC is BSS. BSS is a process that is an inverse operation to a mixing process. In BSS it is assumed that inputs to the mixing systems are statistically independent stochastic processes, where only one input may be Gaussian, others must be non-Gaussian. Standard criterion functions for BDC and BSS are reviewed. Limitations of the second-order statistics and need for higher-order statistics (HOS) or information theoretic criteria that lead to nonlinear optimization algorithms are pointed out. Advantages of various information theoretic criteria for BDC and BSS are discussed. Because gradients of these criteria are nonlinear, resulting optimization algorithms are nonlinear. Linear and non-linear algorithms for BDC and BSS are examined. [Work supported by ONR Codes 321US and 333.]
Blind deconvolution in ocean sound channels via artificial time reversal
Authors: Dowling David R. , Sabra Karim G. , Stevenson Mark R.
Published: October 2013

A signal that travels through a sound channel is typically distorted when recorded by a remote listener because of interference arising from multiple propagation paths. If the distorted signal is recorded with a transducer array, a novel passive acoustic technique, artificial time reversal (ATR), can be used for blind deconvolution to remove sound-channel-induced distortion and recover the original signal. The technique is based on artificial backpropagation of the recorded signals using source-to-array Green’s functions synthesized directly from the recorded signals. The technique relies on separating out the contribution of a propagating mode or ray path having a phase that depends linearly on frequency. Analysis of the technique shows that it is simultaneously a matched filter and an inverse filter in the limit of high signal-to-noise ratio. Computational example’s employing a single source are presented and compared with results obtained from oceanic measurements. The temporal correlation between an ATR-compressed signal and the original signal approaches 100% in the computational examples, and commonly exceeds 90% for the oceanic data. Potential extension of this technique to source–array-range estimation, and to multiple sources emitting simultaneously in the same frequency band are also presented. [Work supported by ONR.]
MPEG-7—Standardized tools for music information retrieval
Authors: Herre Jürgen
Published: October 2013

Today, many applications in Music Information Retrieval (MIR) employ audio features which have been tailored individually by the algorithm developers. For a broader use also in commercial applications, MIR technology can benefit significantly from a ‘‘common language’’ in audio signal description that can be used to annotate any type of multimedia assets in order to facilitate search and retrieval according to a wide range of conceivable criteria in an interoperable way. The audio part of the ISO/MPEG-7 ‘‘Multimedia Content Description Interface’’ provides such a common signal description language by defining a rather comprehensive set of standardized features [called ‘‘low level descriptors’’ (LLDs)], application-centric subsets, and a unified way of exchanging this data based on XML. The talk provides an overview of the MPEG-7 Audio tool chest, including existing and forthcoming extensions. While the idea is clearly to create a universal platform for any conceivable MIR task, some of the initially conceived applications of MPEG-7 Audio are illustrated.
Distributed digital music archives and libraries
Authors: Fujinaga Ichiro
Published: October 2013

The main goal of this research program is to develop and evaluate practices, frameworks, and tools for the design and construction of worldwide distributed digital music archives and libraries. Over the last few millennia, humans have amassed an enormous amount of musical information that is scattered around the world. It is becoming abundantly clear that the optimal path for acquisition is to distribute the task of digitizing the wealth of historical and cultural heritage material that exists in analogue formats, which may include books and manuscripts related to music, music scores, photographs, videos, audio tapes, and phonograph records. In order to achieve this goal, libraries, museums, and archives throughout the world, large or small, need well-researched policies, proper guidance, and efficient tools to digitize their collections and to make them available economically. The research conducted within the program addresses unique and imminent challenges posed by the digitization and dissemination of music media. The are four major research projects in progress: development and evaluation of digitization methods for preservation of analogue recordings; optical music recognition using microfilms; design of workflow management system with automatic metadata extraction; and formulation of interlibrary communication strategies.
Speech-recognition interfaces for music information retrieval
Authors: Goto Masataka
Published: October 2013

This paper describes two hands-free music information retrieval (MIR) systems that enable a user to retrieve and play back a musical piece by saying its title or the artist’s name. Although various interfaces for MIR have been proposed, speech-recognition interfaces suitable for retrieving musical pieces have not been studied. Our MIR-based jukebox systems employ two different speech-recognition interfaces for MIR, speech completion and speech spotter, which exploit intentionally controlled nonverbal speech information in original ways. The first is a music retrieval system with the speech-completion interface that is suitable for music stores and car-driving situations. When a user only remembers part of the name of a musical piece or an artist and utters only a remembered fragment, the system helps the user recall and enter the name by completing the fragment. The second is a background-music playback system with the speech-spotter interface that can enrich human-human conversation. When a user is talking to another person, the system allows the user to enter voice commands for music playback control by spotting a special voice-command utterance in face-to-face or telephone conversations. Experimental results from use of these systems have demonstrated the effectiveness of the speech-completion and speech-spotter interfaces. (Video clips: http://staff.aist.go.jp/m.goto/MIR/speech—if.html)
The lexical accent effects on the perception of fundamental frequency peaks in Japanese
Authors: Shinya Takahito
Published: October 2013

A perceptual experiment was conducted to examine the effects of lexical accent on the perceptual prominence of fundamental frequency peaks (F0) in Japanese. Listeners judged the relative prominence of two peaks (P1 and P2) in sentences in which the peak values and accentedness were varied. When the accentedness of the two peaks did not differ [accented–accented (aa) and unaccented–unaccented (uu)], the results confirmed earlier observations that P2 needs to be lower than P1 to be perceived to be as equally prominent. Moreover, P2 in aa needs to be even lower than P2 in uu to sound equal to P1, due to the perceptual compensation for downstep. However, when accentedness of P1 and P2 differed, to sound equally prominent P2 had to be lower in au than in aa, and P2 had to be higher in ua than in uu. These patterns can be accounted for if the perceived height of an accented word is discounted. The experimental results revealed that lexical accent plays an important role in the perception of intonational prominence in Japanese, and provide evidence for hitherto unknown compensation processes involved in it: downstep compensation and accent discounting.
Allophonic reassignment in dialect adaptation
Authors: German James , Pierrehumbert Janet , Carlson Katy
Published: October 2013

This study explored speakers’ success in acquiring an unfamiliar dialect. Twenty-four speakers of American English attempted to learn Glaswegian, a dialect in which /r/ is produced as a tap. Its closest counterpart is the flap allophone of /t/. The question posed is whether an allophone of one consonant can be remapped to serve as the realization of another consonant. Subjects were trained and tested with materials in which /r/ appeared only in the last word. Each block contained 12 initial and 12 medial /r/’s. A training block was presented twice followed by a generalization block. A week after training, subjects returned for retesting on the original training and generalizations blocks, and a new generalization block. The block order was counterbalanced. Subjects were highly successful at imitating medial /r/ (71%), a striking example of fast categorical remapping in production. Success rates were lower (46%) for /r/ in initial position, where flaps do not appear in English. Generalization and retest results were only slightly worse than original training results, indicating that subjects acquired long-term general knowledge about Glaswegian pronunciation. The slight superiority on familiar materials in the retest phase points to an interaction of lexical learning with general phonological learning.
Speaker specificity in speech perception: the importance of what is and is not in the signal
Authors: Dahan Delphine , Scarborough Rebecca A.
Published: October 2013

In some American English dialects, /ae/ before /g/ (but not before /k/) raises to a vowel approaching [E], in effect reducing phonetic overlap between (e.g.) ‘‘bag’’ and ‘‘back.’’ Here, participants saw four written words on a computer screen (e.g., ‘‘bag,’’ ‘‘back,’’ ‘‘dog,’’ ‘‘dock’’) and heard a spoken word. Their task was to indicate which word they heard. Participants’ eye movements to the written words were recorded. Participants in the ‘‘ae-raising’’ group heard identity-spliced ‘‘bag’’-like words containing the raised vowel [E]; participants in the ‘‘control’’ group heard cross-spliced ‘‘bag’’-like words containing standard [ae]. Acoustically identical ‘‘back’’-like words were subsequently presented to both groups. The ae-raising-group participants identified ‘‘back’’-like words faster and more accurately, and made fewer fixations to the competitor ‘‘bag,’’ than control-group participants did. Thus, exposure to ae-raised realizations of ‘‘bag’’ facilitated the identification of ‘‘back’’ because of the reduced fit between the input and the altered representation of the competing hypothesis ‘‘bag.’’ This demonstrates that listeners evaluate the spoken input with respect to what is, but also what is not, in the signal, and that this evaluation involves speaker-specific representations. [Work supported by NSF Human and Social Dynamics 0433567.]
Reduction of flaps: Speech style, phonological environment, and variability
Authors: Warner Natasha L.
Published: October 2013

Normal connected speech contains a tremendous amount of variability in how a given sound is realized. The current work examines American English /t/ and /d/ in flapping environments. Flaps can be reduced to an approximant or even deleted in connected speech, and this study compares reduction of flaps to reduction of other stops (/p, b, k, g/) in the same environments. The effects of segmental environment (target followed by /l/, syllabic /r/, /∂/, word boundary, etc.), stress (target following stressed syllable versus between two unstressed syllables), and speech style (casual conversation, reading connected text, and word list reading) are analyzed. Target segments are analyzed for presence/absence of a burst and of formants during closure, for duration of the segment and of closure voicing, and for amplitude during the closure or constriction. This project documents the degree of variability in reduction both within and across speakers. Preliminary results show that flaps are reduced to approximants surprisingly often, even in the most careful speech style. The results also suggest that flaps are far more likely to reduce than /p/ or /k/, suggesting that there is a categorical, phonological process at work as well as gradient variability.
Unsupervised segmentation of broad classes from waveforms: Towards a model of early phonological acquisition
Authors: Lin Ying
Published: October 2013

It is commonly held that an important aspect of early phonological acquisition is the ability to learn sound distributions, or statistical learning. Yet significant differences in lexical representations are often observed in studies of infant speech perception, suggesting a protracted process of phonological development. The goal of the current project is to develop a model that links holistic and segmental representation of spoken words, using tools from contemporary speech recognition. In the present stage, the model focuses on the pre-lexical level of phonological development, and tries to identify segmental representations from acoustic signals of isolated words. The segmental representations are based on units that correspond to acoustic phonetic classes, and learning involves updating the unit models in parallel with updating phonotactics. Starting from acoustic segmentations, the model iteratively updates knowledge of the units and phonotactics, and renews segmentation hypotheses regarding each word until convergence. The results of running this algorithm on TIMIT and infant-directed speech data suggest that the model approximately identifies segment-sized broad classes in an unsupervised manner. This statistical approach also provides a different perspective on the role of lexicon in phonological development.
Effects of rhythmic precursors on perception of stress/syllabicity
Authors: Stilp Christian E. , Kluender Keith R.
Published: October 2013

Rhythmic structure is a common property of many environmental sounds including speech. Here, perceptual effects of preceding rhythmic context are assessed in experiments employing edited words for which perceived stress/syllabicity are assessed. A series of edited naturally spoken words varying perceptually from ‘‘polite’’ to ‘‘plight,’’ was created by deleting initial-vowel glottal pulses from a recording of ‘‘polite.’’ Words were identified following nonspeech precursor sequences having either trochaic (strong–weak) or iambic (weak–strong) rhythmic patterns. Precursors consisted of a harmonic spectrum (−6-dB/octave slope) filtered by four sinusoidally modulated single-pole filters. Trochaic (strong–weak) and iambic (weak–strong) rhythmic patterns were created by varying amplitude, pitch, and duration in successive segments (akin to beats) of the precursors. Precursors were comprised of two to six repetitions of these patterns. Following trochaic precursors, listeners were more likely to report hearing ‘‘polite’’ (iambic). This pattern of results indicates that perception did not assimilate to precursor pattern, consistent with rhythmic expectancy. Instead, perception shifted in a way that contrasts with precursor temporal pattern. Additional results with precursors that are more and less like speech are being conducted to further understand how auditory perception adjusts for temporal and spectral regularities. [Work supported by NIDCD.]
Effects of sea surface on underwater communication
Authors: Luo Jing , Badiey Mohsen
Published: October 2013

During High Frequency Experiment in 2003 (HFX-03) various ocean parameters such as the surface wave spectrum, salinity, and temperature profiles were recorded simultaneously with the broadband acoustic signals. Including broadband probe chirps as well as several other communication sequences. Received data are collected and analyzed from different receiver arrays. The statistics of arrival rays and the performances of communication system are studied in two periods of calm and rough sea conditions. Surface reflected rays show variable coherence during different sea surface conditions. This has large influence on the structure of the received signals. Strong dependence between sea surface condition and the performance of communication system is observed. Two types of receiver structures are used and their performances are compared: (1) single channel receiver with decision feedback equalizer, (2) multichannel receiver with signal combining scheme. Similar trends of dependence are found on both receivers. [Work supported by ONR-321OA.]
On shallow-water bottom reverberation angular dependence
Authors: Cable P. G. , Dorfman Y. , Dillow B. , Goldsmith M.
Published: October 2013

Low-frequency monostatic reverberation data obtained during East China Sea ASIAEX in 2001 using Institute of Ocean Acoustics (Beijing) explosive sources and vertical line-receiving array on ShiYan-3 were analyzed in octave bands from 100–800 Hz to determine bottom-scattering strength dependence on bottom-scattering angle. Several methods for estimating the reverberation directionality spectrum were applied and results compared, employing previously described techniques to estimate transmission loss in the extraction of integrated bottom-scattering strength from reverberation [P. G. Cable et al., J. Acoust. Soc. Am. 112, 2362 (2002)]. In the two higher octave bands, scattering angle dependence for grazing angles below critical was found to be approximately proportional to first power of the sine of scattering angle, while estimation bias errors associated with limited angular resolution obscured the behavior in the lowest octave band. [Work supported by ONR under ASIAEX program.]
A numerical adjoint parabolic equation (PE) method for tomography and geoacoustic inversion in shallow water
Authors: Hermand Jean-Pierre , Berrada Mohamed , Meyer Matthias , Asch Mark
Published: October 2013

Recently, an analytic adjoint-based method of optimal nonlocal boundary control has been proposed for inversion of a waveguide acoustic field using the wide-angle parabolic equation [Meyer and Hermand, J. Acoust. Soc. Am. 117, 2937–2948 (2005)]. In this paper a numerical extension of this approach is presented that allows the direct inversion for the geoacoustic parameters which are embedded in a spectral integral representation of the nonlocal boundary condition. The adjoint model is generated numerically and the inversion is carried out jointly across multiple frequencies. The paper further discusses the application of the numerical adjoint PE method for ocean acoustic tomography. To show the effectiveness of the implemented numerical adjoint, preliminary inversion results of water sound-speed profile and bottom acoustic properties will be shown for the YELLOW SHARK ’94 experimental conditions.
Broadband shallow-water reverberation statistics
Authors: Reeves Jon C. , Ferlez Robert J. , Babich Gregory A. , Morella Gary L. , Cuetzo Anthony J.
Published: October 2013

Utilizing a wideband transmitting/receiving system, at-sea experimental results for broadband reverberation have been acquired for both harsh as well as moderate ocean acoustic environments. The principal contributor to the backscattered reverberation is bottom features at the shallow-water ocean sites. Replica correlation (so-called match filter) processing of linear FM (LFM) pulse codes is employed to study the degree of reverberation coherence, as measured by the replica correlation coefficient. The database covers several octaves of bandwidth. The corresponding reverberation coherence is computed in terms of the variance of the cross correlation coefficient (cc) as a function of time–bandwidth product. Of particular interest is the possible departure from Rayleigh statistics as signal bandwidth increases. Several bandwidths are compared, using the Kolmogoroff–Smirnof test as a measure of departure from Rayleigh. [This work was sponsored by A. Nucci, ONR 333.]
Non-Rayleigh reverberation prediction for shallow-water waveguides
Authors: LePage Kevin D.
Published: October 2013

In a previous paper the second moment of monostatic reverberation intensity was derived for rough surfaces in range-independent waveguides with χ21 scatterer amplitude statistics and Gaussian spatial correlation functions [J. Acoust. Soc. Am. 117, 2611 (2005)]. Here, these results are expanded to bistatic geometries and the implications for the degree of non-Rayleighness of the resulting reverberation pressure envelope statistics are discussed. [Work supported by ONR.]